From 7cd3e3f2f301f6b99b0b93119cfcc3d2a2238902 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Thu, 19 May 2022 17:36:25 -0700
Subject: [PATCH 01/37] Preliminary changes

---
 crates/bevy_ecs/src/archetype.rs        | 14 +----
 crates/bevy_ecs/src/storage/mod.rs      |  3 +
 crates/bevy_ecs/src/storage/resource.rs | 36 ++++++++++++
 crates/bevy_ecs/src/world/mod.rs        | 74 ++++++++++---------------
 4 files changed, 70 insertions(+), 57 deletions(-)
 create mode 100644 crates/bevy_ecs/src/storage/resource.rs

diff --git a/crates/bevy_ecs/src/archetype.rs b/crates/bevy_ecs/src/archetype.rs
index ab33119a93be6..82883e683547d 100644
--- a/crates/bevy_ecs/src/archetype.rs
+++ b/crates/bevy_ecs/src/archetype.rs
@@ -5,7 +5,7 @@ use crate::{
     bundle::BundleId,
     component::{ComponentId, StorageType},
     entity::{Entity, EntityLocation},
-    storage::{Column, SparseArray, SparseSet, SparseSetIndex, TableId},
+    storage::{SparseArray, SparseSet, SparseSetIndex, TableId},
 };
 use std::{
     collections::HashMap,
@@ -122,7 +122,6 @@ pub struct Archetype {
     table_info: TableInfo,
     table_components: Box<[ComponentId]>,
     sparse_set_components: Box<[ComponentId]>,
-    pub(crate) unique_components: SparseSet<ComponentId, Column>,
     pub(crate) components: SparseSet<ComponentId, ArchetypeComponentInfo>,
 }
 
@@ -170,7 +169,6 @@ impl Archetype {
             components,
             table_components,
             sparse_set_components,
-            unique_components: SparseSet::new(),
             entities: Default::default(),
             edges: Default::default(),
         }
@@ -206,16 +204,6 @@ impl Archetype {
         &self.sparse_set_components
     }
 
-    #[inline]
-    pub fn unique_components(&self) -> &SparseSet<ComponentId, Column> {
-        &self.unique_components
-    }
-
-    #[inline]
-    pub fn unique_components_mut(&mut self) -> &mut SparseSet<ComponentId, Column> {
-        &mut self.unique_components
-    }
-
     #[inline]
     pub fn components(&self) -> impl Iterator<Item = ComponentId> + '_ {
         self.components.indices()
diff --git a/crates/bevy_ecs/src/storage/mod.rs b/crates/bevy_ecs/src/storage/mod.rs
index f54a2275bfe07..8a43f499f8c6a 100644
--- a/crates/bevy_ecs/src/storage/mod.rs
+++ b/crates/bevy_ecs/src/storage/mod.rs
@@ -3,9 +3,11 @@
 mod blob_vec;
 mod sparse_set;
 mod table;
+mod resource;
 
 pub use blob_vec::*;
 pub use sparse_set::*;
+pub use resource::*;
 pub use table::*;
 
 /// The raw data stores of a [World](crate::world::World)
@@ -13,4 +15,5 @@ pub use table::*;
 pub struct Storages {
     pub sparse_sets: SparseSets,
     pub tables: Tables,
+    pub resources: Resources,
 }
diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
new file mode 100644
index 0000000000000..3f7894c910275
--- /dev/null
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -0,0 +1,36 @@
+use crate::component::ComponentId;
+use crate::archetype::ArchetypeComponentInfo;
+use crate::storage::{SparseSet, Column};
+
+#[derive(Default)]
+pub struct Resources {
+    resources: SparseSet<ComponentId, Column>,
+    components: SparseSet<ComponentId, ArchetypeComponentInfo>,
+}
+
+impl Resources {
+    #[inline]
+    pub(crate) fn columns_mut(&mut self) -> impl Iterator<Item = &mut Column>  {
+        self.resources.values_mut()
+    }
+
+    #[inline]
+    pub(crate) fn components_mut(&mut self) -> &mut SparseSet<ComponentId, ArchetypeComponentInfo>  {
+        &mut self.components
+    }
+
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.resources.len()
+    }
+
+    #[inline]
+    pub(crate) fn get(&self, component: ComponentId) -> Option<&Column>  {
+        self.resources.get(component)
+    }
+
+    #[inline]
+    pub(crate) fn get_mut(&mut self, component: ComponentId) -> Option<&mut Column>  {
+        self.resources.get_mut(component)
+    }
+}
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 71ee4c7a3716b..ebc60459e0bab 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -681,9 +681,7 @@ impl World {
     #[allow(unused_unsafe)]
     pub unsafe fn remove_resource_unchecked<R: 'static>(&mut self) -> Option<R> {
         let component_id = self.components.get_resource_id(TypeId::of::<R>())?;
-        let resource_archetype = self.archetypes.resource_mut();
-        let unique_components = resource_archetype.unique_components_mut();
-        let column = unique_components.get_mut(component_id)?;
+        let column = self.storages.resources.get_mut(component_id)?;
         if column.is_empty() {
             return None;
         }
@@ -755,8 +753,8 @@ impl World {
         match self.get_resource() {
             Some(x) => x,
             None => panic!(
-                "Requested resource {} does not exist in the `World`. 
-                Did you forget to add it using `app.add_resource` / `app.init_resource`? 
+                "Requested resource {} does not exist in the `World`.
+                Did you forget to add it using `app.add_resource` / `app.init_resource`?
                 Resources are also implicitly added via `app.add_event`,
                 and can be added by plugins.",
                 std::any::type_name::<R>()
@@ -779,8 +777,8 @@ impl World {
         match self.get_resource_mut() {
             Some(x) => x,
             None => panic!(
-                "Requested resource {} does not exist in the `World`. 
-                Did you forget to add it using `app.add_resource` / `app.init_resource`? 
+                "Requested resource {} does not exist in the `World`.
+                Did you forget to add it using `app.add_resource` / `app.init_resource`?
                 Resources are also implicitly added via `app.add_event`,
                 and can be added by plugins.",
                 std::any::type_name::<R>()
@@ -841,8 +839,8 @@ impl World {
         match self.get_non_send_resource() {
             Some(x) => x,
             None => panic!(
-                "Requested non-send resource {} does not exist in the `World`. 
-                Did you forget to add it using `app.add_non_send_resource` / `app.init_non_send_resource`? 
+                "Requested non-send resource {} does not exist in the `World`.
+                Did you forget to add it using `app.add_non_send_resource` / `app.init_non_send_resource`?
                 Non-send resources can also be be added by plugins.",
                 std::any::type_name::<R>()
             ),
@@ -861,8 +859,8 @@ impl World {
         match self.get_non_send_resource_mut() {
             Some(x) => x,
             None => panic!(
-                "Requested non-send resource {} does not exist in the `World`. 
-                Did you forget to add it using `app.add_non_send_resource` / `app.init_non_send_resource`? 
+                "Requested non-send resource {} does not exist in the `World`.
+                Did you forget to add it using `app.add_non_send_resource` / `app.init_non_send_resource`?
                 Non-send resources can also be be added by plugins.",
                 std::any::type_name::<R>()
             ),
@@ -1053,9 +1051,7 @@ impl World {
             .get_resource_id(TypeId::of::<R>())
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
         let (ptr, mut ticks) = {
-            let resource_archetype = self.archetypes.resource_mut();
-            let unique_components = resource_archetype.unique_components_mut();
-            let column = unique_components.get_mut(component_id).unwrap_or_else(|| {
+            let column = self.storages.resources.get_mut(component_id).unwrap_or_else(|| {
                 panic!("resource does not exist: {}", std::any::type_name::<R>())
             });
             assert!(
@@ -1081,9 +1077,7 @@ impl World {
         let result = f(self, value_mut);
         assert!(!self.contains_resource::<R>());
 
-        let resource_archetype = self.archetypes.resource_mut();
-        let unique_components = resource_archetype.unique_components_mut();
-        let column = unique_components
+        let column = self.storages.resources
             .get_mut(component_id)
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
 
@@ -1207,29 +1201,24 @@ impl World {
     #[inline]
     unsafe fn initialize_resource_internal(&mut self, component_id: ComponentId) -> &mut Column {
         // SAFE: resource archetype always exists
-        let resource_archetype = self
-            .archetypes
-            .archetypes
-            .get_unchecked_mut(ArchetypeId::RESOURCE.index());
-        let resource_archetype_components = &mut resource_archetype.components;
+        let resources = &mut self.storages.resources;
+        let resources_components = resources.components_mut();
         let archetype_component_count = &mut self.archetypes.archetype_component_count;
         let components = &self.components;
-        resource_archetype
-            .unique_components
-            .get_or_insert_with(component_id, || {
-                resource_archetype_components.insert(
-                    component_id,
-                    ArchetypeComponentInfo {
-                        archetype_component_id: ArchetypeComponentId::new(
-                            *archetype_component_count,
-                        ),
-                        storage_type: StorageType::Table,
-                    },
-                );
-                *archetype_component_count += 1;
-                let component_info = components.get_info_unchecked(component_id);
-                Column::with_capacity(component_info, 1)
-            })
+        resources.get_or_insert_with(component_id, || {
+            resource_archetype_components.insert(
+                component_id,
+                ArchetypeComponentInfo {
+                    archetype_component_id: ArchetypeComponentId::new(
+                        *archetype_component_count,
+                    ),
+                    storage_type: StorageType::Table,
+                },
+            );
+            *archetype_component_count += 1;
+            let component_info = components.get_info_unchecked(component_id);
+            Column::with_capacity(component_info, 1)
+        })
     }
 
     pub(crate) fn initialize_resource<R: Resource>(&mut self) -> ComponentId {
@@ -1251,9 +1240,7 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<&Column> {
-        let resource_archetype = self.archetypes.resource();
-        let unique_components = resource_archetype.unique_components();
-        unique_components.get(component_id).and_then(|column| {
+        self.storages.resources.get(component_id).and_then(|column| {
             if column.is_empty() {
                 None
             } else {
@@ -1321,8 +1308,7 @@ impl World {
         let change_tick = self.change_tick();
         self.storages.tables.check_change_ticks(change_tick);
         self.storages.sparse_sets.check_change_ticks(change_tick);
-        let resource_archetype = self.archetypes.resource_mut();
-        for column in resource_archetype.unique_components.values_mut() {
+        for column in self.storages.resources.columns_mut() {
             column.check_change_ticks(change_tick);
         }
     }
@@ -1458,7 +1444,7 @@ impl fmt::Debug for World {
             .field("component_count", &self.components.len())
             .field(
                 "resource_count",
-                &self.archetypes.resource().unique_components.len(),
+                &self.storages.resources.len(),
             )
             .finish()
     }

From 76ede2f6d85db02a13d5a87376ebd98b2fed9762 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Thu, 19 May 2022 22:57:15 -0700
Subject: [PATCH 02/37] Fix compilation

---
 crates/bevy_ecs/src/archetype.rs           | 29 +-------------
 crates/bevy_ecs/src/lib.rs                 |  8 ++--
 crates/bevy_ecs/src/storage/mod.rs         |  4 +-
 crates/bevy_ecs/src/storage/resource.rs    | 29 +++++++++-----
 crates/bevy_ecs/src/system/system_param.rs | 20 ++++++----
 crates/bevy_ecs/src/world/mod.rs           | 45 ++++++++++++----------
 crates/bevy_ecs/src/world/world_cell.rs    | 35 +++++++++++------
 7 files changed, 88 insertions(+), 82 deletions(-)

diff --git a/crates/bevy_ecs/src/archetype.rs b/crates/bevy_ecs/src/archetype.rs
index 82883e683547d..d7c5aed46a099 100644
--- a/crates/bevy_ecs/src/archetype.rs
+++ b/crates/bevy_ecs/src/archetype.rs
@@ -18,7 +18,6 @@ pub struct ArchetypeId(usize);
 
 impl ArchetypeId {
     pub const EMPTY: ArchetypeId = ArchetypeId(0);
-    pub const RESOURCE: ArchetypeId = ArchetypeId(1);
     pub const INVALID: ArchetypeId = ArchetypeId(usize::MAX);
 
     #[inline]
@@ -122,7 +121,7 @@ pub struct Archetype {
     table_info: TableInfo,
     table_components: Box<[ComponentId]>,
     sparse_set_components: Box<[ComponentId]>,
-    pub(crate) components: SparseSet<ComponentId, ArchetypeComponentInfo>,
+    components: SparseSet<ComponentId, ArchetypeComponentInfo>,
 }
 
 impl Archetype {
@@ -362,17 +361,6 @@ impl Default for Archetypes {
             archetype_component_count: 0,
         };
         archetypes.get_id_or_insert(TableId::empty(), Vec::new(), Vec::new());
-
-        // adds the resource archetype. it is "special" in that it is inaccessible via a "hash",
-        // which prevents entities from being added to it
-        archetypes.archetypes.push(Archetype::new(
-            ArchetypeId::RESOURCE,
-            TableId::empty(),
-            Box::new([]),
-            Box::new([]),
-            Vec::new(),
-            Vec::new(),
-        ));
         archetypes
     }
 }
@@ -403,21 +391,6 @@ impl Archetypes {
         }
     }
 
-    #[inline]
-    pub fn resource(&self) -> &Archetype {
-        // SAFE: resource archetype always exists
-        unsafe { self.archetypes.get_unchecked(ArchetypeId::RESOURCE.index()) }
-    }
-
-    #[inline]
-    pub fn resource_mut(&mut self) -> &mut Archetype {
-        // SAFE: resource archetype always exists
-        unsafe {
-            self.archetypes
-                .get_unchecked_mut(ArchetypeId::RESOURCE.index())
-        }
-    }
-
     #[inline]
     pub fn is_empty(&self) -> bool {
         self.archetypes.is_empty()
diff --git a/crates/bevy_ecs/src/lib.rs b/crates/bevy_ecs/src/lib.rs
index 56ac5db9acd94..db1b27f0598f8 100644
--- a/crates/bevy_ecs/src/lib.rs
+++ b/crates/bevy_ecs/src/lib.rs
@@ -1014,8 +1014,8 @@ mod tests {
             .get_resource_id(TypeId::of::<i32>())
             .unwrap();
         let archetype_component_id = world
-            .archetypes()
-            .resource()
+            .storages()
+            .resources
             .get_archetype_component_id(resource_id)
             .unwrap();
 
@@ -1081,8 +1081,8 @@ mod tests {
         );
 
         let current_archetype_component_id = world
-            .archetypes()
-            .resource()
+            .storages()
+            .resources
             .get_archetype_component_id(current_resource_id)
             .unwrap();
 
diff --git a/crates/bevy_ecs/src/storage/mod.rs b/crates/bevy_ecs/src/storage/mod.rs
index 8a43f499f8c6a..0764ad6046433 100644
--- a/crates/bevy_ecs/src/storage/mod.rs
+++ b/crates/bevy_ecs/src/storage/mod.rs
@@ -1,13 +1,13 @@
 //! Storage layouts for ECS data.
 
 mod blob_vec;
+mod resource;
 mod sparse_set;
 mod table;
-mod resource;
 
 pub use blob_vec::*;
-pub use sparse_set::*;
 pub use resource::*;
+pub use sparse_set::*;
 pub use table::*;
 
 /// The raw data stores of a [World](crate::world::World)
diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 3f7894c910275..2b2fbbdebdedc 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -1,22 +1,28 @@
-use crate::component::ComponentId;
+use crate::archetype::ArchetypeComponentId;
 use crate::archetype::ArchetypeComponentInfo;
-use crate::storage::{SparseSet, Column};
+use crate::component::ComponentId;
+use crate::storage::{Column, SparseSet};
 
 #[derive(Default)]
 pub struct Resources {
-    resources: SparseSet<ComponentId, Column>,
-    components: SparseSet<ComponentId, ArchetypeComponentInfo>,
+    pub(crate) resources: SparseSet<ComponentId, Column>,
+    pub(crate) components: SparseSet<ComponentId, ArchetypeComponentInfo>,
 }
 
 impl Resources {
     #[inline]
-    pub(crate) fn columns_mut(&mut self) -> impl Iterator<Item = &mut Column>  {
+    pub(crate) fn columns_mut(&mut self) -> impl Iterator<Item = &mut Column> {
         self.resources.values_mut()
     }
 
     #[inline]
-    pub(crate) fn components_mut(&mut self) -> &mut SparseSet<ComponentId, ArchetypeComponentInfo>  {
-        &mut self.components
+    pub fn get_archetype_component_id(
+        &self,
+        component_id: ComponentId,
+    ) -> Option<ArchetypeComponentId> {
+        self.components
+            .get(component_id)
+            .map(|info| info.archetype_component_id)
     }
 
     #[inline]
@@ -25,12 +31,17 @@ impl Resources {
     }
 
     #[inline]
-    pub(crate) fn get(&self, component: ComponentId) -> Option<&Column>  {
+    pub fn is_empty(&self) -> bool {
+        self.resources.is_empty()
+    }
+
+    #[inline]
+    pub(crate) fn get(&self, component: ComponentId) -> Option<&Column> {
         self.resources.get(component)
     }
 
     #[inline]
-    pub(crate) fn get_mut(&mut self, component: ComponentId) -> Option<&mut Column>  {
+    pub(crate) fn get_mut(&mut self, component: ComponentId) -> Option<&mut Column> {
         self.resources.get_mut(component)
     }
 }
diff --git a/crates/bevy_ecs/src/system/system_param.rs b/crates/bevy_ecs/src/system/system_param.rs
index 60c9c56ac7717..f9787c6db210b 100644
--- a/crates/bevy_ecs/src/system/system_param.rs
+++ b/crates/bevy_ecs/src/system/system_param.rs
@@ -323,8 +323,9 @@ unsafe impl<T: Resource> SystemParamState for ResState<T> {
         );
         combined_access.add_read(component_id);
 
-        let resource_archetype = world.archetypes.resource();
-        let archetype_component_id = resource_archetype
+        let archetype_component_id = world
+            .storages
+            .resources
             .get_archetype_component_id(component_id)
             .unwrap();
         system_meta
@@ -432,8 +433,9 @@ unsafe impl<T: Resource> SystemParamState for ResMutState<T> {
         }
         combined_access.add_write(component_id);
 
-        let resource_archetype = world.archetypes.resource();
-        let archetype_component_id = resource_archetype
+        let archetype_component_id = world
+            .storages
+            .resources
             .get_archetype_component_id(component_id)
             .unwrap();
         system_meta
@@ -877,8 +879,9 @@ unsafe impl<T: 'static> SystemParamState for NonSendState<T> {
         );
         combined_access.add_read(component_id);
 
-        let resource_archetype = world.archetypes.resource();
-        let archetype_component_id = resource_archetype
+        let archetype_component_id = world
+            .storages
+            .resources
             .get_archetype_component_id(component_id)
             .unwrap();
         system_meta
@@ -991,8 +994,9 @@ unsafe impl<T: 'static> SystemParamState for NonSendMutState<T> {
         }
         combined_access.add_write(component_id);
 
-        let resource_archetype = world.archetypes.resource();
-        let archetype_component_id = resource_archetype
+        let archetype_component_id = world
+            .storages
+            .resources
             .get_archetype_component_id(component_id)
             .unwrap();
         system_meta
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index ebc60459e0bab..2f66f483b6ef6 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -1051,9 +1051,13 @@ impl World {
             .get_resource_id(TypeId::of::<R>())
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
         let (ptr, mut ticks) = {
-            let column = self.storages.resources.get_mut(component_id).unwrap_or_else(|| {
-                panic!("resource does not exist: {}", std::any::type_name::<R>())
-            });
+            let column = self
+                .storages
+                .resources
+                .get_mut(component_id)
+                .unwrap_or_else(|| {
+                    panic!("resource does not exist: {}", std::any::type_name::<R>())
+                });
             assert!(
                 !column.is_empty(),
                 "resource does not exist: {}",
@@ -1077,7 +1081,9 @@ impl World {
         let result = f(self, value_mut);
         assert!(!self.contains_resource::<R>());
 
-        let column = self.storages.resources
+        let column = self
+            .storages
+            .resources
             .get_mut(component_id)
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
 
@@ -1202,16 +1208,15 @@ impl World {
     unsafe fn initialize_resource_internal(&mut self, component_id: ComponentId) -> &mut Column {
         // SAFE: resource archetype always exists
         let resources = &mut self.storages.resources;
-        let resources_components = resources.components_mut();
+        let resource_components = &mut resources.components;
+        let resources = &mut resources.resources;
         let archetype_component_count = &mut self.archetypes.archetype_component_count;
         let components = &self.components;
         resources.get_or_insert_with(component_id, || {
-            resource_archetype_components.insert(
+            resource_components.insert(
                 component_id,
                 ArchetypeComponentInfo {
-                    archetype_component_id: ArchetypeComponentId::new(
-                        *archetype_component_count,
-                    ),
+                    archetype_component_id: ArchetypeComponentId::new(*archetype_component_count),
                     storage_type: StorageType::Table,
                 },
             );
@@ -1240,13 +1245,16 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<&Column> {
-        self.storages.resources.get(component_id).and_then(|column| {
-            if column.is_empty() {
-                None
-            } else {
-                Some(column)
-            }
-        })
+        self.storages
+            .resources
+            .get(component_id)
+            .and_then(|column| {
+                if column.is_empty() {
+                    None
+                } else {
+                    Some(column)
+                }
+            })
     }
 
     pub(crate) fn validate_non_send_access<T: 'static>(&self) {
@@ -1442,10 +1450,7 @@ impl fmt::Debug for World {
             .field("entity_count", &self.entities.len())
             .field("archetype_count", &self.archetypes.len())
             .field("component_count", &self.components.len())
-            .field(
-                "resource_count",
-                &self.storages.resources.len(),
-            )
+            .field("resource_count", &self.storages.resources.len())
             .finish()
     }
 }
diff --git a/crates/bevy_ecs/src/world/world_cell.rs b/crates/bevy_ecs/src/world/world_cell.rs
index 5a1fff6cdf9a2..3a6bd6e4eefc2 100644
--- a/crates/bevy_ecs/src/world/world_cell.rs
+++ b/crates/bevy_ecs/src/world/world_cell.rs
@@ -183,8 +183,11 @@ impl<'w> WorldCell<'w> {
     /// Gets a reference to the resource of the given type
     pub fn get_resource<T: Resource>(&self) -> Option<WorldBorrow<'_, T>> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
-        let resource_archetype = self.world.archetypes.resource();
-        let archetype_component_id = resource_archetype.get_archetype_component_id(component_id)?;
+        let archetype_component_id = self
+            .world
+            .storages
+            .resources
+            .get_archetype_component_id(component_id)?;
         Some(WorldBorrow::new(
             // SAFE: ComponentId matches TypeId
             unsafe { self.world.get_resource_with_id(component_id)? },
@@ -215,8 +218,11 @@ impl<'w> WorldCell<'w> {
     /// Gets a mutable reference to the resource of the given type
     pub fn get_resource_mut<T: Resource>(&self) -> Option<WorldBorrowMut<'_, T>> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
-        let resource_archetype = self.world.archetypes.resource();
-        let archetype_component_id = resource_archetype.get_archetype_component_id(component_id)?;
+        let archetype_component_id = self
+            .world
+            .storages
+            .resources
+            .get_archetype_component_id(component_id)?;
         Some(WorldBorrowMut::new(
             // SAFE: ComponentId matches TypeId and access is checked by WorldBorrowMut
             unsafe {
@@ -250,8 +256,11 @@ impl<'w> WorldCell<'w> {
     /// Gets an immutable reference to the non-send resource of the given type, if it exists.
     pub fn get_non_send_resource<T: 'static>(&self) -> Option<WorldBorrow<'_, T>> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
-        let resource_archetype = self.world.archetypes.resource();
-        let archetype_component_id = resource_archetype.get_archetype_component_id(component_id)?;
+        let archetype_component_id = self
+            .world
+            .storages
+            .resources
+            .get_archetype_component_id(component_id)?;
         Some(WorldBorrow::new(
             // SAFE: ComponentId matches TypeId
             unsafe { self.world.get_non_send_with_id(component_id)? },
@@ -282,8 +291,11 @@ impl<'w> WorldCell<'w> {
     /// Gets a mutable reference to the non-send resource of the given type, if it exists.
     pub fn get_non_send_resource_mut<T: 'static>(&self) -> Option<WorldBorrowMut<'_, T>> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
-        let resource_archetype = self.world.archetypes.resource();
-        let archetype_component_id = resource_archetype.get_archetype_component_id(component_id)?;
+        let archetype_component_id = self
+            .world
+            .storages
+            .resources
+            .get_archetype_component_id(component_id)?;
         Some(WorldBorrowMut::new(
             // SAFE: ComponentId matches TypeId and access is checked by WorldBorrowMut
             unsafe {
@@ -318,7 +330,7 @@ impl<'w> WorldCell<'w> {
 #[cfg(test)]
 mod tests {
     use super::BASE_ACCESS;
-    use crate::{archetype::ArchetypeId, world::World};
+    use crate::world::World;
     use std::any::TypeId;
 
     #[test]
@@ -374,8 +386,9 @@ mod tests {
             .components
             .get_resource_id(TypeId::of::<u32>())
             .unwrap();
-        let resource_archetype = world.archetypes.get(ArchetypeId::RESOURCE).unwrap();
-        let u32_archetype_component_id = resource_archetype
+        let u32_archetype_component_id = world
+            .storages
+            .resources
             .get_archetype_component_id(u32_component_id)
             .unwrap();
         assert_eq!(world.archetype_component_access.access.len(), 1);

From b7b16be34ef0027b408a149eecd779f26061200c Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 30 May 2022 19:28:29 -0700
Subject: [PATCH 03/37] Provide internal helper function

---
 crates/bevy_ecs/src/system/system_param.rs | 16 ++++------------
 crates/bevy_ecs/src/world/mod.rs           | 11 +++++++++++
 crates/bevy_ecs/src/world/world_cell.rs    | 20 +++++---------------
 3 files changed, 20 insertions(+), 27 deletions(-)

diff --git a/crates/bevy_ecs/src/system/system_param.rs b/crates/bevy_ecs/src/system/system_param.rs
index f9787c6db210b..49bac5469c1b7 100644
--- a/crates/bevy_ecs/src/system/system_param.rs
+++ b/crates/bevy_ecs/src/system/system_param.rs
@@ -324,9 +324,7 @@ unsafe impl<T: Resource> SystemParamState for ResState<T> {
         combined_access.add_read(component_id);
 
         let archetype_component_id = world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)
+            .get_resource_archetype_component_id(component_id)
             .unwrap();
         system_meta
             .archetype_component_access
@@ -434,9 +432,7 @@ unsafe impl<T: Resource> SystemParamState for ResMutState<T> {
         combined_access.add_write(component_id);
 
         let archetype_component_id = world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)
+            .get_resource_archetype_component_id(component_id)
             .unwrap();
         system_meta
             .archetype_component_access
@@ -880,9 +876,7 @@ unsafe impl<T: 'static> SystemParamState for NonSendState<T> {
         combined_access.add_read(component_id);
 
         let archetype_component_id = world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)
+            .get_resource_archetype_component_id(component_id)
             .unwrap();
         system_meta
             .archetype_component_access
@@ -995,9 +989,7 @@ unsafe impl<T: 'static> SystemParamState for NonSendMutState<T> {
         combined_access.add_write(component_id);
 
         let archetype_component_id = world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)
+            .get_resource_archetype_component_id(component_id)
             .unwrap();
         system_meta
             .archetype_component_access
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 2f66f483b6ef6..5e63e6dbc4460 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -896,6 +896,17 @@ impl World {
         self.get_non_send_unchecked_mut_with_id(component_id)
     }
 
+    // Shorthand helper function for getting the [`ArchetypeComponentId`] for a resource.
+    #[inline]
+    pub(crate) fn get_resource_archetype_component_id(
+        &self,
+        component_id: ComponentId,
+    ) -> Option<ArchetypeComponentId> {
+        self.storages
+            .resources
+            .get_archetype_component_id(component_id)
+    }
+
     /// For a given batch of ([Entity], [Bundle]) pairs, either spawns each [Entity] with the given
     /// bundle (if the entity does not exist), or inserts the [Bundle] (if the entity already exists).
     /// This is faster than doing equivalent operations one-by-one.
diff --git a/crates/bevy_ecs/src/world/world_cell.rs b/crates/bevy_ecs/src/world/world_cell.rs
index 3a6bd6e4eefc2..dfdaf27143b0b 100644
--- a/crates/bevy_ecs/src/world/world_cell.rs
+++ b/crates/bevy_ecs/src/world/world_cell.rs
@@ -185,9 +185,7 @@ impl<'w> WorldCell<'w> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
         let archetype_component_id = self
             .world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)?;
+            .get_resource_archetype_component_id(component_id)?;
         Some(WorldBorrow::new(
             // SAFE: ComponentId matches TypeId
             unsafe { self.world.get_resource_with_id(component_id)? },
@@ -220,9 +218,7 @@ impl<'w> WorldCell<'w> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
         let archetype_component_id = self
             .world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)?;
+            .get_resource_archetype_component_id(component_id)?;
         Some(WorldBorrowMut::new(
             // SAFE: ComponentId matches TypeId and access is checked by WorldBorrowMut
             unsafe {
@@ -258,9 +254,7 @@ impl<'w> WorldCell<'w> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
         let archetype_component_id = self
             .world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)?;
+            .get_resource_archetype_component_id(component_id)?;
         Some(WorldBorrow::new(
             // SAFE: ComponentId matches TypeId
             unsafe { self.world.get_non_send_with_id(component_id)? },
@@ -293,9 +287,7 @@ impl<'w> WorldCell<'w> {
         let component_id = self.world.components.get_resource_id(TypeId::of::<T>())?;
         let archetype_component_id = self
             .world
-            .storages
-            .resources
-            .get_archetype_component_id(component_id)?;
+            .get_resource_archetype_component_id(component_id)?;
         Some(WorldBorrowMut::new(
             // SAFE: ComponentId matches TypeId and access is checked by WorldBorrowMut
             unsafe {
@@ -387,9 +379,7 @@ mod tests {
             .get_resource_id(TypeId::of::<u32>())
             .unwrap();
         let u32_archetype_component_id = world
-            .storages
-            .resources
-            .get_archetype_component_id(u32_component_id)
+            .get_resource_archetype_component_id(u32_component_id)
             .unwrap();
         assert_eq!(world.archetype_component_access.access.len(), 1);
         assert_eq!(

From 5464d47f8244648b12e65fb75c4c1de82f8d453f Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 30 May 2022 22:32:55 -0700
Subject: [PATCH 04/37] More complete Resources impl

---
 crates/bevy_ecs/src/storage/resource.rs    |  93 ++++++++++++--
 crates/bevy_ecs/src/system/system_param.rs |  60 +++++----
 crates/bevy_ecs/src/world/mod.rs           | 134 +++++++--------------
 3 files changed, 161 insertions(+), 126 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 2b2fbbdebdedc..1c0094bd76223 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -1,8 +1,14 @@
 use crate::archetype::ArchetypeComponentId;
 use crate::archetype::ArchetypeComponentInfo;
-use crate::component::ComponentId;
+use crate::component::{ComponentId, ComponentTicks};
 use crate::storage::{Column, SparseSet};
+use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
+use std::cell::UnsafeCell;
 
+/// The backing store for all [`Resource`]s stored in the [`World`].
+///
+/// [`Resource`]: crate::system::system_param::Resource
+/// [`World`]: crate::world::World
 #[derive(Default)]
 pub struct Resources {
     pub(crate) resources: SparseSet<ComponentId, Column>,
@@ -10,11 +16,7 @@ pub struct Resources {
 }
 
 impl Resources {
-    #[inline]
-    pub(crate) fn columns_mut(&mut self) -> impl Iterator<Item = &mut Column> {
-        self.resources.values_mut()
-    }
-
+    /// Gets the [`ArchetypeComponentId`] for a given resoruce.
     #[inline]
     pub fn get_archetype_component_id(
         &self,
@@ -25,23 +27,94 @@ impl Resources {
             .map(|info| info.archetype_component_id)
     }
 
+    /// The total number of resoruces stored in the [`World`]
+    ///
+    /// [`World`]: crate::world::World
     #[inline]
     pub fn len(&self) -> usize {
         self.resources.len()
     }
 
+    /// Returns true if there are no resources stored in the [`World`],
+    /// false otherwise.
+    ///
+    /// [`World`]: crate::world::World
     #[inline]
     pub fn is_empty(&self) -> bool {
         self.resources.is_empty()
     }
 
     #[inline]
-    pub(crate) fn get(&self, component: ComponentId) -> Option<&Column> {
-        self.resources.get(component)
+    pub fn get(&self, component_id: ComponentId) -> Option<Ptr<'_>> {
+        let column = self.resources.get(component_id)?;
+        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
+        // ptr value / drop is called when R is dropped
+        (!column.is_empty()).then(|| unsafe { column.get_data_unchecked(0) })
+    }
+
+    #[inline]
+    pub fn get_mut(&mut self, component_id: ComponentId) -> Option<PtrMut<'_>> {
+        let column = self.resources.get_mut(component_id)?;
+        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
+        // ptr value / drop is called when R is dropped
+        (!column.is_empty()).then(|| unsafe { column.get_data_unchecked_mut(0) })
+    }
+
+    #[inline]
+    pub fn get_ticks(&self, component_id: ComponentId) -> Option<&ComponentTicks> {
+        let column = self.resources.get(component_id)?;
+        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
+        // ptr value / drop is called when R is dropped
+        (!column.is_empty()).then(|| unsafe { column.get_ticks_unchecked(0).deref() })
+    }
+
+    #[inline]
+    pub fn contains(&self, component_id: ComponentId) -> bool {
+        self.resources.contains(component_id)
     }
 
     #[inline]
-    pub(crate) fn get_mut(&mut self, component: ComponentId) -> Option<&mut Column> {
-        self.resources.get_mut(component)
+    pub(crate) fn get_with_ticks_unchecked(
+        &self,
+        component_id: ComponentId,
+    ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
+        let column = self.resources.get(component_id)?;
+        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
+        // ptr value / drop is called when R is dropped
+        (!column.is_empty())
+            .then(|| unsafe { (column.get_data_unchecked(0), column.get_ticks_unchecked(0)) })
+    }
+
+    // # Safety
+    // - ptr must point to valid data of this column's component type
+    #[inline]
+    pub unsafe fn insert(
+        &mut self,
+        component_id: ComponentId,
+        data: OwningPtr<'_>,
+        ticks: ComponentTicks,
+    ) -> Option<()> {
+        let column = self.resources.get_mut(component_id)?;
+        debug_assert!(column.is_empty());
+        column.push(data, ticks);
+        Some(())
+    }
+
+    #[inline]
+    #[must_use = "The returned pointer to the removed component should be used or dropped"]
+    pub fn remove(&mut self, component_id: ComponentId) -> Option<(OwningPtr<'_>, ComponentTicks)> {
+        let column = self.resources.get_mut(component_id)?;
+        if column.is_empty() {
+            return None;
+        }
+        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
+        // ptr value / drop is called when R is dropped
+        unsafe { Some(column.swap_remove_and_forget_unchecked(0)) }
+    }
+
+    pub fn check_change_ticks(&mut self, change_tick: u32) {
+        for column in self.storages.resources.columns_mut() {
+            column.check_change_ticks(change_tick);
+        }
     }
 }
diff --git a/crates/bevy_ecs/src/system/system_param.rs b/crates/bevy_ecs/src/system/system_param.rs
index 49bac5469c1b7..04f5bc61caf77 100644
--- a/crates/bevy_ecs/src/system/system_param.rs
+++ b/crates/bevy_ecs/src/system/system_param.rs
@@ -346,8 +346,10 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for ResState<T> {
         world: &'w World,
         change_tick: u32,
     ) -> Self::Item {
-        let column = world
-            .get_populated_resource_column(state.component_id)
+        let (ptr, ticks) = world
+            .storages()
+            .resources
+            .get_with_ticks_unchecked(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Resource requested by {} does not exist: {}",
@@ -356,8 +358,8 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for ResState<T> {
                 )
             });
         Res {
-            value: column.get_data_ptr().deref::<T>(),
-            ticks: column.get_ticks_unchecked(0).deref(),
+            value: ptr.deref(),
+            ticks: ticks.deref(),
             last_change_tick: system_meta.last_change_tick,
             change_tick,
         }
@@ -393,10 +395,12 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for OptionResState<T> {
         change_tick: u32,
     ) -> Self::Item {
         world
-            .get_populated_resource_column(state.0.component_id)
-            .map(|column| Res {
-                value: column.get_data_ptr().deref::<T>(),
-                ticks: column.get_ticks_unchecked(0).deref(),
+            .storages()
+            .resources
+            .get_with_ticks_unchecked(state.0.component_id)
+            .map(|(ptr, ticks)| Res {
+                value: ptr.deref(),
+                ticks: ticks.deref(),
                 last_change_tick: system_meta.last_change_tick,
                 change_tick,
             })
@@ -899,8 +903,10 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendState<T> {
         change_tick: u32,
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
-        let column = world
-            .get_populated_resource_column(state.component_id)
+        let (ptr, ticks) = world
+            .storages()
+            .resources
+            .get_with_ticks_unchecked(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Non-send resource requested by {} does not exist: {}",
@@ -910,8 +916,8 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendState<T> {
             });
 
         NonSend {
-            value: column.get_data_ptr().deref::<T>(),
-            ticks: column.get_ticks_unchecked(0).read(),
+            value: ptr.deref(),
+            ticks: ticks.read(),
             last_change_tick: system_meta.last_change_tick,
             change_tick,
         }
@@ -948,10 +954,12 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for OptionNonSendState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         world
-            .get_populated_resource_column(state.0.component_id)
-            .map(|column| NonSend {
-                value: column.get_data_ptr().deref::<T>(),
-                ticks: column.get_ticks_unchecked(0).read(),
+            .storages()
+            .resources
+            .get_with_ticks_unchecked(state.0.component_id)
+            .map(|(ptr, ticks)| NonSend {
+                value: ptr.deref(),
+                ticks: ticks.read(),
                 last_change_tick: system_meta.last_change_tick,
                 change_tick,
             })
@@ -1012,8 +1020,10 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendMutState<T> {
         change_tick: u32,
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
-        let column = world
-            .get_populated_resource_column(state.component_id)
+        let (ptr, ticks) = world
+            .storages()
+            .resources
+            .get_with_ticks_unchecked(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Non-send resource requested by {} does not exist: {}",
@@ -1022,9 +1032,9 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendMutState<T> {
                 )
             });
         NonSendMut {
-            value: column.get_data_ptr().assert_unique().deref_mut::<T>(),
+            value: ptr.assert_unique().deref_mut(),
             ticks: Ticks {
-                component_ticks: column.get_ticks_unchecked(0).deref_mut(),
+                component_ticks: ticks.deref_mut(),
                 last_change_tick: system_meta.last_change_tick,
                 change_tick,
             },
@@ -1059,11 +1069,13 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for OptionNonSendMutState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         world
-            .get_populated_resource_column(state.0.component_id)
-            .map(|column| NonSendMut {
-                value: column.get_data_ptr().assert_unique().deref_mut::<T>(),
+            .storages()
+            .resources
+            .get_with_ticks_unchecked(state.0.component_id)
+            .map(|(ptr, ticks)| NonSendMut {
+                value: ptr.assert_unique().deref_mut(),
                 ticks: Ticks {
-                    component_ticks: column.get_ticks_unchecked(0).deref_mut(),
+                    component_ticks: ticks.deref_mut(),
                     last_change_tick: system_meta.last_change_tick,
                     change_tick,
                 },
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 5e63e6dbc4460..47664d10a51da 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -681,61 +681,37 @@ impl World {
     #[allow(unused_unsafe)]
     pub unsafe fn remove_resource_unchecked<R: 'static>(&mut self) -> Option<R> {
         let component_id = self.components.get_resource_id(TypeId::of::<R>())?;
-        let column = self.storages.resources.get_mut(component_id)?;
-        if column.is_empty() {
-            return None;
+        // SAFE: the resource is of type R and the value is returned back to the caller.
+        // The access here must not be used on non-send types.
+        unsafe {
+            let (ptr, _) = self.storages.resources.remove(component_id)?;
+            Some(ptr.read::<R>())
         }
-        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
-        // ptr value / drop is called when R is dropped
-        let (ptr, _) = unsafe { column.swap_remove_and_forget_unchecked(0) };
-        // SAFE: column is of type R
-        Some(unsafe { ptr.read::<R>() })
     }
 
     /// Returns `true` if a resource of type `R` exists. Otherwise returns `false`.
     #[inline]
     pub fn contains_resource<R: 'static>(&self) -> bool {
-        let component_id =
-            if let Some(component_id) = self.components.get_resource_id(TypeId::of::<R>()) {
-                component_id
-            } else {
-                return false;
-            };
-        self.get_populated_resource_column(component_id).is_some()
+        self.components
+            .get_resource_id(TypeId::of::<R>())
+            .map(|component_id| self.storages.resources.contains(component_id))
+            .unwrap_or(false)
     }
 
     pub fn is_resource_added<R: Resource>(&self) -> bool {
-        let component_id =
-            if let Some(component_id) = self.components.get_resource_id(TypeId::of::<R>()) {
-                component_id
-            } else {
-                return false;
-            };
-        let column = if let Some(column) = self.get_populated_resource_column(component_id) {
-            column
-        } else {
-            return false;
-        };
-        // SAFE: resources table always have row 0
-        let ticks = unsafe { column.get_ticks_unchecked(0).deref() };
-        ticks.is_added(self.last_change_tick(), self.read_change_tick())
+        self.components
+            .get_resource_id(TypeId::of::<R>())
+            .and_then(|component_id| self.storages.resources.get_ticks(component_id))
+            .map(|ticks| ticks.is_added(self.last_change_tick(), self.read_change_tick()))
+            .unwrap_or(false)
     }
 
     pub fn is_resource_changed<R: Resource>(&self) -> bool {
-        let component_id =
-            if let Some(component_id) = self.components.get_resource_id(TypeId::of::<R>()) {
-                component_id
-            } else {
-                return false;
-            };
-        let column = if let Some(column) = self.get_populated_resource_column(component_id) {
-            column
-        } else {
-            return false;
-        };
-        // SAFE: resources table always have row 0
-        let ticks = unsafe { column.get_ticks_unchecked(0).deref() };
-        ticks.is_changed(self.last_change_tick(), self.read_change_tick())
+        self.components
+            .get_resource_id(TypeId::of::<R>())
+            .and_then(|component_id| self.storages.resources.get_ticks(component_id))
+            .map(|ticks| ticks.is_changed(self.last_change_tick(), self.read_change_tick()))
+            .unwrap_or(false)
     }
 
     /// Gets a reference to the resource of the given type
@@ -1061,23 +1037,11 @@ impl World {
             .components
             .get_resource_id(TypeId::of::<R>())
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
-        let (ptr, mut ticks) = {
-            let column = self
-                .storages
-                .resources
-                .get_mut(component_id)
-                .unwrap_or_else(|| {
-                    panic!("resource does not exist: {}", std::any::type_name::<R>())
-                });
-            assert!(
-                !column.is_empty(),
-                "resource does not exist: {}",
-                std::any::type_name::<R>()
-            );
-            // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of
-            // the ptr value / drop is called when R is dropped
-            unsafe { column.swap_remove_and_forget_unchecked(0) }
-        };
+        let (ptr, mut ticks) = self
+            .storages
+            .resources
+            .remove(component_id)
+            .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
         // SAFE: pointer is of type R
         // Read the value onto the stack to avoid potential mut aliasing.
         let mut value = unsafe { ptr.read::<R>() };
@@ -1092,18 +1056,18 @@ impl World {
         let result = f(self, value_mut);
         assert!(!self.contains_resource::<R>());
 
-        let column = self
-            .storages
-            .resources
-            .get_mut(component_id)
-            .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
-
         OwningPtr::make(value, |ptr| {
             unsafe {
                 // SAFE: pointer is of type R
-                column.push(ptr, ticks);
+                self.storages
+                    .resources
+                    .insert(component_id, ptr, ticks)
+                    .unwrap_or_else(|| {
+                        panic!("resource does not exist: {}", std::any::type_name::<R>())
+                    });
             }
         });
+
         result
     }
 
@@ -1114,8 +1078,10 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<&R> {
-        let column = self.get_populated_resource_column(component_id)?;
-        Some(column.get_data_ptr().deref::<R>())
+        self.storages
+            .resources
+            .get(component_id)
+            .map(|ptr| ptr.deref())
     }
 
     /// # Safety
@@ -1126,11 +1092,14 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<Mut<'_, R>> {
-        let column = self.get_populated_resource_column(component_id)?;
+        let (ptr, ticks) = self
+            .storages
+            .resources
+            .get_with_ticks_unchecked(component_id)?;
         Some(Mut {
-            value: column.get_data_ptr().assert_unique().deref_mut(),
+            value: ptr.assert_unique().deref_mut(),
             ticks: Ticks {
-                component_ticks: column.get_ticks_unchecked(0).deref_mut(),
+                component_ticks: ticks.deref_mut(),
                 last_change_tick: self.last_change_tick(),
                 change_tick: self.read_change_tick(),
             },
@@ -1251,23 +1220,6 @@ impl World {
         component_id
     }
 
-    /// returns the resource column if the requested resource exists
-    pub(crate) fn get_populated_resource_column(
-        &self,
-        component_id: ComponentId,
-    ) -> Option<&Column> {
-        self.storages
-            .resources
-            .get(component_id)
-            .and_then(|column| {
-                if column.is_empty() {
-                    None
-                } else {
-                    Some(column)
-                }
-            })
-    }
-
     pub(crate) fn validate_non_send_access<T: 'static>(&self) {
         assert!(
             self.main_thread_validator.is_main_thread(),
@@ -1327,9 +1279,7 @@ impl World {
         let change_tick = self.change_tick();
         self.storages.tables.check_change_ticks(change_tick);
         self.storages.sparse_sets.check_change_ticks(change_tick);
-        for column in self.storages.resources.columns_mut() {
-            column.check_change_ticks(change_tick);
-        }
+        self.storages.resources.check_change_ticks(change_tick);
     }
 
     pub fn clear_entities(&mut self) {

From 32c5456859ee2f69cbd19e66f98175d818018f38 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 30 May 2022 22:45:25 -0700
Subject: [PATCH 05/37] Fix build

---
 crates/bevy_ecs/src/storage/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 1c0094bd76223..3a4a53620e709 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -113,7 +113,7 @@ impl Resources {
     }
 
     pub fn check_change_ticks(&mut self, change_tick: u32) {
-        for column in self.storages.resources.columns_mut() {
+        for column in self.resources.values_mut() {
             column.check_change_ticks(change_tick);
         }
     }

From bb9a49fc70d7ad3df1e3f2196b2cc588574136a5 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 30 May 2022 22:52:05 -0700
Subject: [PATCH 06/37] Cleanup

---
 crates/bevy_ecs/src/system/system_param.rs | 24 ++++++----------------
 crates/bevy_ecs/src/world/mod.rs           | 16 +++++++++++----
 2 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/crates/bevy_ecs/src/system/system_param.rs b/crates/bevy_ecs/src/system/system_param.rs
index 04f5bc61caf77..2049837b1aaed 100644
--- a/crates/bevy_ecs/src/system/system_param.rs
+++ b/crates/bevy_ecs/src/system/system_param.rs
@@ -347,9 +347,7 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for ResState<T> {
         change_tick: u32,
     ) -> Self::Item {
         let (ptr, ticks) = world
-            .storages()
-            .resources
-            .get_with_ticks_unchecked(state.component_id)
+            .get_resource_with_ticks_unchecked(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Resource requested by {} does not exist: {}",
@@ -395,9 +393,7 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for OptionResState<T> {
         change_tick: u32,
     ) -> Self::Item {
         world
-            .storages()
-            .resources
-            .get_with_ticks_unchecked(state.0.component_id)
+            .get_resource_with_ticks_unchecked(state.0.component_id)
             .map(|(ptr, ticks)| Res {
                 value: ptr.deref(),
                 ticks: ticks.deref(),
@@ -904,9 +900,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         let (ptr, ticks) = world
-            .storages()
-            .resources
-            .get_with_ticks_unchecked(state.component_id)
+            .get_resource_with_ticks_unchecked(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Non-send resource requested by {} does not exist: {}",
@@ -954,9 +948,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for OptionNonSendState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         world
-            .storages()
-            .resources
-            .get_with_ticks_unchecked(state.0.component_id)
+            .get_resource_with_ticks_unchecked(state.0.component_id)
             .map(|(ptr, ticks)| NonSend {
                 value: ptr.deref(),
                 ticks: ticks.read(),
@@ -1021,9 +1013,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendMutState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         let (ptr, ticks) = world
-            .storages()
-            .resources
-            .get_with_ticks_unchecked(state.component_id)
+            .get_resource_with_ticks_unchecked(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Non-send resource requested by {} does not exist: {}",
@@ -1069,9 +1059,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for OptionNonSendMutState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         world
-            .storages()
-            .resources
-            .get_with_ticks_unchecked(state.0.component_id)
+            .get_resource_with_ticks_unchecked(state.0.component_id)
             .map(|(ptr, ticks)| NonSendMut {
                 value: ptr.assert_unique().deref_mut(),
                 ticks: Ticks {
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 47664d10a51da..342fd8316c893 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -872,6 +872,17 @@ impl World {
         self.get_non_send_unchecked_mut_with_id(component_id)
     }
 
+    // Shorthand helper function for getting the data and change ticks for a resource.
+    #[inline]
+    pub(crate) fn get_resource_with_ticks_unchecked(
+        &self,
+        component_id: ComponentId,
+    ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
+        self.storages
+            .resources
+            .get_with_ticks_unchecked(component_id)
+    }
+
     // Shorthand helper function for getting the [`ArchetypeComponentId`] for a resource.
     #[inline]
     pub(crate) fn get_resource_archetype_component_id(
@@ -1092,10 +1103,7 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<Mut<'_, R>> {
-        let (ptr, ticks) = self
-            .storages
-            .resources
-            .get_with_ticks_unchecked(component_id)?;
+        let (ptr, ticks) = self.get_resource_with_ticks_unchecked(component_id)?;
         Some(Mut {
             value: ptr.assert_unique().deref_mut(),
             ticks: Ticks {

From b719c1bbd4313a818cccccefef64a34cd8bb07f6 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 30 May 2022 23:13:59 -0700
Subject: [PATCH 07/37] Fix CI

---
 crates/bevy_ecs/src/storage/resource.rs | 11 +++++++----
 crates/bevy_ecs/src/world/mod.rs        |  1 +
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 3a4a53620e709..4679ff84db23a 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -7,7 +7,7 @@ use std::cell::UnsafeCell;
 
 /// The backing store for all [`Resource`]s stored in the [`World`].
 ///
-/// [`Resource`]: crate::system::system_param::Resource
+/// [`Resource`]: crate::system::Resource
 /// [`World`]: crate::world::World
 #[derive(Default)]
 pub struct Resources {
@@ -70,7 +70,10 @@ impl Resources {
 
     #[inline]
     pub fn contains(&self, component_id: ComponentId) -> bool {
-        self.resources.contains(component_id)
+        self.resources
+            .get(component_id)
+            .map(|column| !column.is_empty())
+            .unwrap_or(false)
     }
 
     #[inline]
@@ -85,8 +88,8 @@ impl Resources {
             .then(|| unsafe { (column.get_data_unchecked(0), column.get_ticks_unchecked(0)) })
     }
 
-    // # Safety
-    // - ptr must point to valid data of this column's component type
+    /// # Safety
+    /// - ptr must point to valid data of this column's component type
     #[inline]
     pub unsafe fn insert(
         &mut self,
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 342fd8316c893..a5da40825d93e 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -23,6 +23,7 @@ use bevy_ptr::{OwningPtr, Ptr, UnsafeCellDeref};
 use bevy_utils::tracing::debug;
 use std::{
     any::TypeId,
+    cell::UnsafeCell,
     fmt,
     sync::atomic::{AtomicU32, Ordering},
 };

From 99f14d703d001fe257f56b8f2af28a984c61c65d Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Tue, 7 Jun 2022 01:47:25 -0700
Subject: [PATCH 08/37] Fix CI

---
 crates/bevy_ecs/src/storage/resource.rs    | 16 +++++++++-
 crates/bevy_ecs/src/system/system_param.rs | 12 ++++----
 crates/bevy_ecs/src/world/mod.rs           | 36 ++++++----------------
 3 files changed, 31 insertions(+), 33 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 4679ff84db23a..ebf98aef63497 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -77,7 +77,7 @@ impl Resources {
     }
 
     #[inline]
-    pub(crate) fn get_with_ticks_unchecked(
+    pub(crate) fn get_with_ticks(
         &self,
         component_id: ComponentId,
     ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
@@ -115,6 +115,20 @@ impl Resources {
         unsafe { Some(column.swap_remove_and_forget_unchecked(0)) }
     }
 
+    #[inline]
+    pub(crate) fn remove_and_drop(&mut self, component_id: ComponentId) -> Option<()> {
+        let column = self.resources.get_mut(component_id)?;
+        if column.is_empty() {
+            return None;
+        }
+        // SAFE: if a resource column exists, row 0 exists as well. The removed value is dropped
+        // immediately.
+        unsafe {
+            column.swap_remove_unchecked(0);
+            Some(())
+        }
+    }
+
     pub fn check_change_ticks(&mut self, change_tick: u32) {
         for column in self.resources.values_mut() {
             column.check_change_ticks(change_tick);
diff --git a/crates/bevy_ecs/src/system/system_param.rs b/crates/bevy_ecs/src/system/system_param.rs
index 2049837b1aaed..5b46dafe55aaa 100644
--- a/crates/bevy_ecs/src/system/system_param.rs
+++ b/crates/bevy_ecs/src/system/system_param.rs
@@ -347,7 +347,7 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for ResState<T> {
         change_tick: u32,
     ) -> Self::Item {
         let (ptr, ticks) = world
-            .get_resource_with_ticks_unchecked(state.component_id)
+            .get_resource_with_ticks(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Resource requested by {} does not exist: {}",
@@ -393,7 +393,7 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for OptionResState<T> {
         change_tick: u32,
     ) -> Self::Item {
         world
-            .get_resource_with_ticks_unchecked(state.0.component_id)
+            .get_resource_with_ticks(state.0.component_id)
             .map(|(ptr, ticks)| Res {
                 value: ptr.deref(),
                 ticks: ticks.deref(),
@@ -900,7 +900,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         let (ptr, ticks) = world
-            .get_resource_with_ticks_unchecked(state.component_id)
+            .get_resource_with_ticks(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Non-send resource requested by {} does not exist: {}",
@@ -948,7 +948,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for OptionNonSendState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         world
-            .get_resource_with_ticks_unchecked(state.0.component_id)
+            .get_resource_with_ticks(state.0.component_id)
             .map(|(ptr, ticks)| NonSend {
                 value: ptr.deref(),
                 ticks: ticks.read(),
@@ -1013,7 +1013,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendMutState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         let (ptr, ticks) = world
-            .get_resource_with_ticks_unchecked(state.component_id)
+            .get_resource_with_ticks(state.component_id)
             .unwrap_or_else(|| {
                 panic!(
                     "Non-send resource requested by {} does not exist: {}",
@@ -1059,7 +1059,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for OptionNonSendMutState<T> {
     ) -> Self::Item {
         world.validate_non_send_access::<T>();
         world
-            .get_resource_with_ticks_unchecked(state.0.component_id)
+            .get_resource_with_ticks(state.0.component_id)
             .map(|(ptr, ticks)| NonSendMut {
                 value: ptr.assert_unique().deref_mut(),
                 ticks: Ticks {
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index a5da40825d93e..fdbf8211a1253 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -875,13 +875,11 @@ impl World {
 
     // Shorthand helper function for getting the data and change ticks for a resource.
     #[inline]
-    pub(crate) fn get_resource_with_ticks_unchecked(
+    pub(crate) fn get_resource_with_ticks(
         &self,
         component_id: ComponentId,
     ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
-        self.storages
-            .resources
-            .get_with_ticks_unchecked(component_id)
+        self.storages.resources.get_with_ticks(component_id)
     }
 
     // Shorthand helper function for getting the [`ArchetypeComponentId`] for a resource.
@@ -1104,7 +1102,7 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<Mut<'_, R>> {
-        let (ptr, ticks) = self.get_resource_with_ticks_unchecked(component_id)?;
+        let (ptr, ticks) = self.get_resource_with_ticks(component_id)?;
         Some(Mut {
             value: ptr.assert_unique().deref_mut(),
             ticks: Ticks {
@@ -1312,9 +1310,7 @@ impl World {
         if !info.is_send_and_sync() {
             self.validate_non_send_access_untyped(info.name());
         }
-
-        let column = self.get_populated_resource_column(component_id)?;
-        Some(column.get_data_ptr())
+        self.storages.resources.get(component_id)
     }
 
     /// Gets a resource to the resource with the id [`ComponentId`] if it exists.
@@ -1330,20 +1326,18 @@ impl World {
             self.validate_non_send_access_untyped(info.name());
         }
 
-        let column = self.get_populated_resource_column(component_id)?;
+        let (ptr, ticks) = self.get_resource_with_ticks(component_id)?;
 
-        // SAFE: get_data_ptr requires that the mutability rules are not violated, and the caller promises
-        // to only modify the resource while the mutable borrow of the world is valid
+        // SAFE: This funtion xclusive access to the world. The ptr must have unique access.
         let ticks = Ticks {
-            // - index is in-bounds because the column is initialized and non-empty
-            // - no other reference to the ticks of the same row can exist at the same time
-            component_ticks: unsafe { &mut *column.get_ticks_unchecked(0).get() },
+            component_ticks: unsafe { ticks.deref_mut() },
             last_change_tick: self.last_change_tick(),
             change_tick: self.read_change_tick(),
         };
 
         Some(MutUntyped {
-            value: unsafe { column.get_data_ptr().assert_unique() },
+            // SAFE: This funtion xclusive access to the world. The ptr must have unique access.
+            value: unsafe { ptr.assert_unique() },
             ticks,
         })
     }
@@ -1357,17 +1351,7 @@ impl World {
         if !info.is_send_and_sync() {
             self.validate_non_send_access_untyped(info.name());
         }
-
-        let resource_archetype = self.archetypes.resource_mut();
-        let unique_components = resource_archetype.unique_components_mut();
-        let column = unique_components.get_mut(component_id)?;
-        if column.is_empty() {
-            return None;
-        }
-        // SAFE: if a resource column exists, row 0 exists as well
-        unsafe { column.swap_remove_unchecked(0) };
-
-        Some(())
+        self.storages.resources.remove_and_drop(component_id)
     }
 
     /// Retrieves a mutable untyped reference to the given `entity`'s [Component] of the given [`ComponentId`].

From 4918e10c35410618752c0babd954752cf18a909c Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Tue, 7 Jun 2022 02:10:05 -0700
Subject: [PATCH 09/37] Shrink Resources

---
 crates/bevy_ecs/src/storage/resource.rs | 46 +++++++++++++++++--------
 crates/bevy_ecs/src/world/mod.rs        | 31 +++++++++--------
 2 files changed, 48 insertions(+), 29 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index ebf98aef63497..4a1603b1e01f3 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -5,14 +5,18 @@ use crate::storage::{Column, SparseSet};
 use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
 use std::cell::UnsafeCell;
 
+pub(crate) struct ResourceInfo {
+    pub data: Column,
+    pub component_info: ArchetypeComponentInfo,
+}
+
 /// The backing store for all [`Resource`]s stored in the [`World`].
 ///
 /// [`Resource`]: crate::system::Resource
 /// [`World`]: crate::world::World
 #[derive(Default)]
 pub struct Resources {
-    pub(crate) resources: SparseSet<ComponentId, Column>,
-    pub(crate) components: SparseSet<ComponentId, ArchetypeComponentInfo>,
+    pub(crate) resources: SparseSet<ComponentId, ResourceInfo>,
 }
 
 impl Resources {
@@ -22,9 +26,9 @@ impl Resources {
         &self,
         component_id: ComponentId,
     ) -> Option<ArchetypeComponentId> {
-        self.components
+        self.resources
             .get(component_id)
-            .map(|info| info.archetype_component_id)
+            .map(|info| info.component_info.archetype_component_id)
     }
 
     /// The total number of resoruces stored in the [`World`]
@@ -44,35 +48,39 @@ impl Resources {
         self.resources.is_empty()
     }
 
+    /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
     pub fn get(&self, component_id: ComponentId) -> Option<Ptr<'_>> {
-        let column = self.resources.get(component_id)?;
+        let column = &self.resources.get(component_id)?.data;
         // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
         // ptr value / drop is called when R is dropped
         (!column.is_empty()).then(|| unsafe { column.get_data_unchecked(0) })
     }
 
+    /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
     pub fn get_mut(&mut self, component_id: ComponentId) -> Option<PtrMut<'_>> {
-        let column = self.resources.get_mut(component_id)?;
+        let column = &mut self.resources.get_mut(component_id)?.data;
         // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
         // ptr value / drop is called when R is dropped
         (!column.is_empty()).then(|| unsafe { column.get_data_unchecked_mut(0) })
     }
 
+    /// Gets the [`ComponentTicks`] to a resource, if available.
     #[inline]
     pub fn get_ticks(&self, component_id: ComponentId) -> Option<&ComponentTicks> {
-        let column = self.resources.get(component_id)?;
+        let column = &self.resources.get(component_id)?.data;
         // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
         // ptr value / drop is called when R is dropped
         (!column.is_empty()).then(|| unsafe { column.get_ticks_unchecked(0).deref() })
     }
 
+    /// Checks if the a resource is currently stored with a given ID.
     #[inline]
     pub fn contains(&self, component_id: ComponentId) -> bool {
         self.resources
             .get(component_id)
-            .map(|column| !column.is_empty())
+            .map(|info| !info.data.is_empty())
             .unwrap_or(false)
     }
 
@@ -81,15 +89,18 @@ impl Resources {
         &self,
         component_id: ComponentId,
     ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
-        let column = self.resources.get(component_id)?;
+        let column = &self.resources.get(component_id)?.data;
         // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
         // ptr value / drop is called when R is dropped
         (!column.is_empty())
             .then(|| unsafe { (column.get_data_unchecked(0), column.get_ticks_unchecked(0)) })
     }
 
+    /// Inserts a resource into the world.
+    ///
     /// # Safety
-    /// - ptr must point to valid data of this column's component type
+    /// ptr must point to valid data of this column's component type which
+    /// must correspond to the provided ID.
     #[inline]
     pub unsafe fn insert(
         &mut self,
@@ -97,16 +108,21 @@ impl Resources {
         data: OwningPtr<'_>,
         ticks: ComponentTicks,
     ) -> Option<()> {
-        let column = self.resources.get_mut(component_id)?;
+        let column = &mut self.resources.get_mut(component_id)?.data;
         debug_assert!(column.is_empty());
         column.push(data, ticks);
         Some(())
     }
 
+    /// Removes a resource from the world.
+    ///
+    /// # Safety
+    /// ptr must point to valid data of this column's component type which
+    /// must correspond to the provided ID.
     #[inline]
     #[must_use = "The returned pointer to the removed component should be used or dropped"]
     pub fn remove(&mut self, component_id: ComponentId) -> Option<(OwningPtr<'_>, ComponentTicks)> {
-        let column = self.resources.get_mut(component_id)?;
+        let column = &mut self.resources.get_mut(component_id)?.data;
         if column.is_empty() {
             return None;
         }
@@ -117,7 +133,7 @@ impl Resources {
 
     #[inline]
     pub(crate) fn remove_and_drop(&mut self, component_id: ComponentId) -> Option<()> {
-        let column = self.resources.get_mut(component_id)?;
+        let column = &mut self.resources.get_mut(component_id)?.data;
         if column.is_empty() {
             return None;
         }
@@ -130,8 +146,8 @@ impl Resources {
     }
 
     pub fn check_change_ticks(&mut self, change_tick: u32) {
-        for column in self.resources.values_mut() {
-            column.check_change_ticks(change_tick);
+        for info in self.resources.values_mut() {
+            info.data.check_change_ticks(change_tick);
         }
     }
 }
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index fdbf8211a1253..1f1c3541e1add 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -16,7 +16,7 @@ use crate::{
     },
     entity::{AllocAtWithoutReplacement, Entities, Entity},
     query::{QueryState, WorldQuery},
-    storage::{Column, SparseSet, Storages},
+    storage::{Column, ResourceInfo, SparseSet, Storages},
     system::Resource,
 };
 use bevy_ptr::{OwningPtr, Ptr, UnsafeCellDeref};
@@ -1195,22 +1195,25 @@ impl World {
     unsafe fn initialize_resource_internal(&mut self, component_id: ComponentId) -> &mut Column {
         // SAFE: resource archetype always exists
         let resources = &mut self.storages.resources;
-        let resource_components = &mut resources.components;
         let resources = &mut resources.resources;
         let archetype_component_count = &mut self.archetypes.archetype_component_count;
         let components = &self.components;
-        resources.get_or_insert_with(component_id, || {
-            resource_components.insert(
-                component_id,
-                ArchetypeComponentInfo {
-                    archetype_component_id: ArchetypeComponentId::new(*archetype_component_count),
-                    storage_type: StorageType::Table,
-                },
-            );
-            *archetype_component_count += 1;
-            let component_info = components.get_info_unchecked(component_id);
-            Column::with_capacity(component_info, 1)
-        })
+        &mut resources
+            .get_or_insert_with(component_id, || {
+                let component_info = components.get_info_unchecked(component_id);
+                let info = ResourceInfo {
+                    data: Column::with_capacity(component_info, 1),
+                    component_info: ArchetypeComponentInfo {
+                        archetype_component_id: ArchetypeComponentId::new(
+                            *archetype_component_count,
+                        ),
+                        storage_type: StorageType::Table,
+                    },
+                };
+                *archetype_component_count += 1;
+                info
+            })
+            .data
     }
 
     pub(crate) fn initialize_resource<R: Resource>(&mut self) -> ComponentId {

From 2b24bac19634d943fc099f696f9529bef3e389f3 Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Sat, 11 Jun 2022 15:54:06 -0700
Subject: [PATCH 10/37] Less jank way of fetching ticks.

Co-authored-by: Boxy <supbscripter@gmail.com>
---
 crates/bevy_ecs/src/storage/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 4a1603b1e01f3..9c56056629302 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -72,7 +72,7 @@ impl Resources {
         let column = &self.resources.get(component_id)?.data;
         // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
         // ptr value / drop is called when R is dropped
-        (!column.is_empty()).then(|| unsafe { column.get_ticks_unchecked(0).deref() })
+        column.get_ticks_slice().get(0).map(|ticks| unsafe { ticks.deref() })
     }
 
     /// Checks if the a resource is currently stored with a given ID.

From ab675d1e3bf64742d218b7b7d25328c244c93763 Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Sat, 11 Jun 2022 15:55:27 -0700
Subject: [PATCH 11/37] Better safety comment.

Co-authored-by: Boxy <supbscripter@gmail.com>
---
 crates/bevy_ecs/src/world/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 1f1c3541e1add..974cfcd367e47 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -1331,7 +1331,7 @@ impl World {
 
         let (ptr, ticks) = self.get_resource_with_ticks(component_id)?;
 
-        // SAFE: This funtion xclusive access to the world. The ptr must have unique access.
+        // SAFE: This function has exclusive access to the world so nothing aliases `ticks`.
         let ticks = Ticks {
             component_ticks: unsafe { ticks.deref_mut() },
             last_change_tick: self.last_change_tick(),

From bd25ccc4c90ad642be9fd85a02acfb2966a965b4 Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Sat, 11 Jun 2022 15:55:35 -0700
Subject: [PATCH 12/37] Better safety comment.

Co-authored-by: Boxy <supbscripter@gmail.com>
---
 crates/bevy_ecs/src/world/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 974cfcd367e47..ecb9659fd3b7b 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -1339,7 +1339,7 @@ impl World {
         };
 
         Some(MutUntyped {
-            // SAFE: This funtion xclusive access to the world. The ptr must have unique access.
+            // SAFE: This function has exclusive access to the world so nothing aliases `ptr`.
             value: unsafe { ptr.assert_unique() },
             ticks,
         })

From 70578fe6806f7b4a5d24a85638adc00ddbd1d28e Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Sat, 11 Jun 2022 15:56:24 -0700
Subject: [PATCH 13/37] Correct safety comment pointing to the right parameter.

Co-authored-by: Boxy <supbscripter@gmail.com>
---
 crates/bevy_ecs/src/storage/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 9c56056629302..6e026e3405525 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -99,7 +99,7 @@ impl Resources {
     /// Inserts a resource into the world.
     ///
     /// # Safety
-    /// ptr must point to valid data of this column's component type which
+    /// `data` must point to valid data of this column's component type which
     /// must correspond to the provided ID.
     #[inline]
     pub unsafe fn insert(

From 27ce1a361d8a175378c3cac4767f99954eae2ed3 Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Sat, 11 Jun 2022 15:56:56 -0700
Subject: [PATCH 14/37] Much simpler remove impl.

Co-authored-by: Boxy <supbscripter@gmail.com>
---
 crates/bevy_ecs/src/storage/resource.rs | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 6e026e3405525..f55447efb39d5 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -134,15 +134,7 @@ impl Resources {
     #[inline]
     pub(crate) fn remove_and_drop(&mut self, component_id: ComponentId) -> Option<()> {
         let column = &mut self.resources.get_mut(component_id)?.data;
-        if column.is_empty() {
-            return None;
-        }
-        // SAFE: if a resource column exists, row 0 exists as well. The removed value is dropped
-        // immediately.
-        unsafe {
-            column.swap_remove_unchecked(0);
-            Some(())
-        }
+        (column.len() > 0).then(|| column.clear())
     }
 
     pub fn check_change_ticks(&mut self, change_tick: u32) {

From 520fd3062586298e76c2a46d72001da74f2a20e9 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Wed, 15 Jun 2022 03:22:19 -0700
Subject: [PATCH 15/37] Update safety comments

---
 crates/bevy_ecs/src/storage/resource.rs | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index f55447efb39d5..7731bceadf3b8 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -52,8 +52,7 @@ impl Resources {
     #[inline]
     pub fn get(&self, component_id: ComponentId) -> Option<Ptr<'_>> {
         let column = &self.resources.get(component_id)?.data;
-        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
-        // ptr value / drop is called when R is dropped
+        // SAFE: This checks that the column is not empty, so row 0 must exist.
         (!column.is_empty()).then(|| unsafe { column.get_data_unchecked(0) })
     }
 
@@ -61,8 +60,7 @@ impl Resources {
     #[inline]
     pub fn get_mut(&mut self, component_id: ComponentId) -> Option<PtrMut<'_>> {
         let column = &mut self.resources.get_mut(component_id)?.data;
-        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
-        // ptr value / drop is called when R is dropped
+        // SAFE: This checks that the column is not empty, so row 0 must exist.
         (!column.is_empty()).then(|| unsafe { column.get_data_unchecked_mut(0) })
     }
 
@@ -70,8 +68,7 @@ impl Resources {
     #[inline]
     pub fn get_ticks(&self, component_id: ComponentId) -> Option<&ComponentTicks> {
         let column = &self.resources.get(component_id)?.data;
-        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
-        // ptr value / drop is called when R is dropped
+        // SAFE: If row 0exists, it's ComponentTicks must be valid as well.
         column.get_ticks_slice().get(0).map(|ticks| unsafe { ticks.deref() })
     }
 
@@ -90,8 +87,7 @@ impl Resources {
         component_id: ComponentId,
     ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
         let column = &self.resources.get(component_id)?.data;
-        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
-        // ptr value / drop is called when R is dropped
+        // SAFE: This checks that the column is not empty, so row 0 must exist.
         (!column.is_empty())
             .then(|| unsafe { (column.get_data_unchecked(0), column.get_ticks_unchecked(0)) })
     }
@@ -126,8 +122,8 @@ impl Resources {
         if column.is_empty() {
             return None;
         }
-        // SAFE: if a resource column exists, row 0 exists as well. caller takes ownership of the
-        // ptr value / drop is called when R is dropped
+        // SAFE: This checks that the column is not empty, so row 0 must exist. caller takes ownership 
+        // of the ptr value / drop is called when R is dropped
         unsafe { Some(column.swap_remove_and_forget_unchecked(0)) }
     }
 

From 7737705486613a5412a5bdf65101d07f6d819ad8 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Wed, 15 Jun 2022 03:31:18 -0700
Subject: [PATCH 16/37] Move the unsafe into Column

---
 crates/bevy_ecs/src/storage/resource.rs | 13 ++++---------
 crates/bevy_ecs/src/storage/table.rs    | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 7731bceadf3b8..9651aafc9e5a6 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -51,25 +51,20 @@ impl Resources {
     /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
     pub fn get(&self, component_id: ComponentId) -> Option<Ptr<'_>> {
-        let column = &self.resources.get(component_id)?.data;
-        // SAFE: This checks that the column is not empty, so row 0 must exist.
-        (!column.is_empty()).then(|| unsafe { column.get_data_unchecked(0) })
+        self.resources.get(component_id)?.data.get_data(0)
     }
 
     /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
     pub fn get_mut(&mut self, component_id: ComponentId) -> Option<PtrMut<'_>> {
-        let column = &mut self.resources.get_mut(component_id)?.data;
-        // SAFE: This checks that the column is not empty, so row 0 must exist.
-        (!column.is_empty()).then(|| unsafe { column.get_data_unchecked_mut(0) })
+        self.resources.get_mut(component_id)?.data.get_data_mut(0)
     }
 
     /// Gets the [`ComponentTicks`] to a resource, if available.
     #[inline]
     pub fn get_ticks(&self, component_id: ComponentId) -> Option<&ComponentTicks> {
-        let column = &self.resources.get(component_id)?.data;
-        // SAFE: If row 0exists, it's ComponentTicks must be valid as well.
-        column.get_ticks_slice().get(0).map(|ticks| unsafe { ticks.deref() })
+        // SAFE: If row 0 exists, it's ComponentTicks must be valid as well.
+        self.resources.get(component_id)?.data.get_ticks(0).map(|ticks| unsafe { ticks.deref() })
     }
 
     /// Checks if the a resource is currently stored with a given ID.
diff --git a/crates/bevy_ecs/src/storage/table.rs b/crates/bevy_ecs/src/storage/table.rs
index a571a631d66c2..e365fdb071c2e 100644
--- a/crates/bevy_ecs/src/storage/table.rs
+++ b/crates/bevy_ecs/src/storage/table.rs
@@ -147,6 +147,13 @@ impl Column {
         &self.ticks
     }
 
+    #[inline]
+    pub fn get_data(&self, row: usize) -> Option<Ptr<'_>> {
+        // SAFETY: The row is length checked before fetching the pointer. This is being
+        // accessed through a read-only reference to the column.
+        (row < self.data.len()).then(|| unsafe { self.data.get_unchecked(row)})
+    }
+
     /// # Safety
     /// - index must be in-bounds
     /// - no other reference to the data of the same row can exist at the same time
@@ -156,6 +163,13 @@ impl Column {
         self.data.get_unchecked(row)
     }
 
+    #[inline]
+    pub fn get_data_mut(&mut self, row: usize) -> Option<PtrMut<'_>> {
+        // SAFETY: The row is length checked before fetching the pointer. This is being
+        // accessed through an exclusive reference to the column.
+        (row < self.data.len()).then(|| unsafe { self.data.get_unchecked_mut(row)})
+    }
+
     /// # Safety
     /// - index must be in-bounds
     /// - no other reference to the data of the same row can exist at the same time
@@ -165,6 +179,11 @@ impl Column {
         self.data.get_unchecked_mut(row)
     }
 
+    #[inline]
+    pub fn get_ticks(&self, row: usize) -> Option<&UnsafeCell<ComponentTicks>> {
+        self.ticks.get(row)
+    }
+
     /// # Safety
     /// index must be in-bounds
     #[inline]

From a6b5e4bdd54caeefeeb457273052c3335e0557eb Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Wed, 15 Jun 2022 03:35:10 -0700
Subject: [PATCH 17/37] Column::get

---
 crates/bevy_ecs/src/storage/resource.rs |  5 +----
 crates/bevy_ecs/src/storage/table.rs    | 13 +++++++++++++
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 9651aafc9e5a6..efaca8050fe52 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -81,10 +81,7 @@ impl Resources {
         &self,
         component_id: ComponentId,
     ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
-        let column = &self.resources.get(component_id)?.data;
-        // SAFE: This checks that the column is not empty, so row 0 must exist.
-        (!column.is_empty())
-            .then(|| unsafe { (column.get_data_unchecked(0), column.get_ticks_unchecked(0)) })
+        self.resources.get(component_id)?.data.get(0)
     }
 
     /// Inserts a resource into the world.
diff --git a/crates/bevy_ecs/src/storage/table.rs b/crates/bevy_ecs/src/storage/table.rs
index e365fdb071c2e..f7a43029aba77 100644
--- a/crates/bevy_ecs/src/storage/table.rs
+++ b/crates/bevy_ecs/src/storage/table.rs
@@ -147,6 +147,19 @@ impl Column {
         &self.ticks
     }
 
+    #[inline]
+    pub fn get(&self, row: usize) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
+        // SAFETY: The row is length checked before fetching the pointer. This is being
+        // accessed through a read-only reference to the column.
+        (row < self.data.len()).then(|| unsafe { 
+            (
+                self.data.get_unchecked(row),
+                self.ticks.get_unchecked(row)
+            )
+        })
+    }
+
+
     #[inline]
     pub fn get_data(&self, row: usize) -> Option<Ptr<'_>> {
         // SAFETY: The row is length checked before fetching the pointer. This is being

From 610c617543b0b3122064c756d9e1224c78a4686c Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Wed, 15 Jun 2022 03:43:29 -0700
Subject: [PATCH 18/37] Formatting

---
 crates/bevy_ecs/src/storage/resource.rs | 17 ++++++++-------
 crates/bevy_ecs/src/storage/table.rs    | 29 +++++++++++++++++--------
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index efaca8050fe52..095631c7094f7 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -64,7 +64,11 @@ impl Resources {
     #[inline]
     pub fn get_ticks(&self, component_id: ComponentId) -> Option<&ComponentTicks> {
         // SAFE: If row 0 exists, it's ComponentTicks must be valid as well.
-        self.resources.get(component_id)?.data.get_ticks(0).map(|ticks| unsafe { ticks.deref() })
+        self.resources
+            .get(component_id)?
+            .data
+            .get_ticks(0)
+            .map(|ticks| unsafe { ticks.deref() })
     }
 
     /// Checks if the a resource is currently stored with a given ID.
@@ -110,13 +114,10 @@ impl Resources {
     #[inline]
     #[must_use = "The returned pointer to the removed component should be used or dropped"]
     pub fn remove(&mut self, component_id: ComponentId) -> Option<(OwningPtr<'_>, ComponentTicks)> {
-        let column = &mut self.resources.get_mut(component_id)?.data;
-        if column.is_empty() {
-            return None;
-        }
-        // SAFE: This checks that the column is not empty, so row 0 must exist. caller takes ownership 
-        // of the ptr value / drop is called when R is dropped
-        unsafe { Some(column.swap_remove_and_forget_unchecked(0)) }
+        self.resources
+            .get_mut(component_id)?
+            .data
+            .swap_remove_and_forget(0)
     }
 
     #[inline]
diff --git a/crates/bevy_ecs/src/storage/table.rs b/crates/bevy_ecs/src/storage/table.rs
index f7a43029aba77..965874e4e6df1 100644
--- a/crates/bevy_ecs/src/storage/table.rs
+++ b/crates/bevy_ecs/src/storage/table.rs
@@ -107,6 +107,22 @@ impl Column {
         self.ticks.swap_remove(row);
     }
 
+    #[inline]
+    #[must_use = "The returned pointer should be used to dropped the removed component"]
+    pub(crate) fn swap_remove_and_forget(
+        &mut self,
+        row: usize,
+    ) -> Option<(OwningPtr<'_>, ComponentTicks)> {
+        (row > self.data.len()).then(|| {
+            // SAFETY: The row was length checked before this.
+            let data = unsafe { self.data.swap_remove_and_forget_unchecked(row) };
+            let ticks = self.ticks.swap_remove(row).into_inner();
+            (data, ticks)
+        })
+    }
+
+    /// # Safety
+    /// index must be in-bounds
     #[inline]
     #[must_use = "The returned pointer should be used to dropped the removed component"]
     pub(crate) unsafe fn swap_remove_and_forget_unchecked(
@@ -151,20 +167,15 @@ impl Column {
     pub fn get(&self, row: usize) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
         // SAFETY: The row is length checked before fetching the pointer. This is being
         // accessed through a read-only reference to the column.
-        (row < self.data.len()).then(|| unsafe { 
-            (
-                self.data.get_unchecked(row),
-                self.ticks.get_unchecked(row)
-            )
-        })
+        (row < self.data.len())
+            .then(|| unsafe { (self.data.get_unchecked(row), self.ticks.get_unchecked(row)) })
     }
 
-
     #[inline]
     pub fn get_data(&self, row: usize) -> Option<Ptr<'_>> {
         // SAFETY: The row is length checked before fetching the pointer. This is being
         // accessed through a read-only reference to the column.
-        (row < self.data.len()).then(|| unsafe { self.data.get_unchecked(row)})
+        (row < self.data.len()).then(|| unsafe { self.data.get_unchecked(row) })
     }
 
     /// # Safety
@@ -180,7 +191,7 @@ impl Column {
     pub fn get_data_mut(&mut self, row: usize) -> Option<PtrMut<'_>> {
         // SAFETY: The row is length checked before fetching the pointer. This is being
         // accessed through an exclusive reference to the column.
-        (row < self.data.len()).then(|| unsafe { self.data.get_unchecked_mut(row)})
+        (row < self.data.len()).then(|| unsafe { self.data.get_unchecked_mut(row) })
     }
 
     /// # Safety

From e32ec9e8a0f2eae1640e7211ef24e9fadc7428cd Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Wed, 15 Jun 2022 03:47:42 -0700
Subject: [PATCH 19/37] Address World review comments

---
 crates/bevy_ecs/src/world/mod.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index ecb9659fd3b7b..0e0a241868c92 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -683,7 +683,6 @@ impl World {
     pub unsafe fn remove_resource_unchecked<R: 'static>(&mut self) -> Option<R> {
         let component_id = self.components.get_resource_id(TypeId::of::<R>())?;
         // SAFE: the resource is of type R and the value is returned back to the caller.
-        // The access here must not be used on non-send types.
         unsafe {
             let (ptr, _) = self.storages.resources.remove(component_id)?;
             Some(ptr.read::<R>())
@@ -1194,8 +1193,7 @@ impl World {
     #[inline]
     unsafe fn initialize_resource_internal(&mut self, component_id: ComponentId) -> &mut Column {
         // SAFE: resource archetype always exists
-        let resources = &mut self.storages.resources;
-        let resources = &mut resources.resources;
+        let resources = &mut self.storages.resources.resources;
         let archetype_component_count = &mut self.archetypes.archetype_component_count;
         let components = &self.components;
         &mut resources

From 515e2b3ae9c145a3ed1e8185affce5ac1f929f3e Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Wed, 15 Jun 2022 05:09:30 -0700
Subject: [PATCH 20/37] Make storage APIs a bit more externally friendly

---
 crates/bevy_ecs/src/storage/resource.rs | 194 ++++++++++++++----------
 crates/bevy_ecs/src/storage/table.rs    |  12 ++
 crates/bevy_ecs/src/world/mod.rs        |  96 +++++-------
 3 files changed, 167 insertions(+), 135 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 095631c7094f7..31515871e2067 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -1,13 +1,99 @@
 use crate::archetype::ArchetypeComponentId;
 use crate::archetype::ArchetypeComponentInfo;
-use crate::component::{ComponentId, ComponentTicks};
+use crate::component::{ComponentId, ComponentTicks, Components, StorageType};
 use crate::storage::{Column, SparseSet};
 use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
 use std::cell::UnsafeCell;
 
-pub(crate) struct ResourceInfo {
-    pub data: Column,
-    pub component_info: ArchetypeComponentInfo,
+pub struct ResourceInfo {
+    column: Column,
+    component_info: ArchetypeComponentInfo,
+}
+
+impl ResourceInfo {
+    /// Returns true if the resource is populated.
+    #[inline]
+    pub fn is_present(&self) -> bool {
+        !self.column.is_empty()
+    }
+
+    #[inline]
+    pub(crate) fn component_info(&self) -> &ArchetypeComponentInfo {
+        &self.component_info
+    }
+
+    /// Gets a read-only pointer to the underlying resource, if available.
+    #[inline]
+    pub fn get_data(&self) -> Option<Ptr<'_>> {
+        self.column.get_data(0)
+    }
+
+    /// Gets a mutable pointer to the underlying resource, if available.
+    #[inline]
+    pub fn get_data_mut(&mut self) -> Option<PtrMut<'_>> {
+        self.column.get_data_mut(0)
+    }
+
+    /// Gets a read-only reference to the change ticks of the underlying resource, if available.
+    #[inline]
+    pub fn get_ticks(&self) -> Option<&ComponentTicks> {
+        self.column
+            .get_ticks(0)
+            .map(|ticks| unsafe { ticks.deref() })
+    }
+
+    /// Gets a mutable reference to the change ticks of the underlying resource, if available.
+    #[inline]
+    pub fn get_ticks_mut(&mut self) -> Option<&mut ComponentTicks> {
+        self.column
+            .get_ticks(0)
+            .map(|ticks| unsafe { ticks.deref_mut() })
+    }
+
+    #[inline]
+    pub(crate) fn get_with_ticks(&self) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
+        self.column.get(0)
+    }
+
+    /// Inserts a value into the resource. If a value is already present
+    /// it will be replaced.
+    ///
+    /// # Safety
+    /// `value` must be valid for the underlying type for the resource.
+    #[inline]
+    pub unsafe fn insert(&mut self, value: OwningPtr<'_>, change_tick: u32) {
+        if self.is_present() {
+            self.column.replace(0, value, change_tick);
+        } else {
+            self.column.push(value, ComponentTicks::new(change_tick));
+        }
+    }
+
+    #[inline]
+    pub(crate) unsafe fn insert_with_ticks(
+        &mut self,
+        value: OwningPtr<'_>,
+        change_ticks: ComponentTicks,
+    ) {
+        if self.is_present() {
+            self.column.replace_untracked(0, value);
+            *self.column.get_ticks_unchecked_mut(0) = change_ticks;
+        } else {
+            self.column.push(value, change_ticks);
+        }
+    }
+
+    /// Removes a value from the resource, if present.
+    #[inline]
+    #[must_use = "The returned pointer to the removed component should be used or dropped"]
+    pub fn remove(&mut self) -> Option<(OwningPtr<'_>, ComponentTicks)> {
+        self.column.swap_remove_and_forget(0)
+    }
+
+    #[inline]
+    pub(crate) fn remove_and_drop(&mut self) {
+        self.column.clear();
+    }
 }
 
 /// The backing store for all [`Resource`]s stored in the [`World`].
@@ -16,21 +102,10 @@ pub(crate) struct ResourceInfo {
 /// [`World`]: crate::world::World
 #[derive(Default)]
 pub struct Resources {
-    pub(crate) resources: SparseSet<ComponentId, ResourceInfo>,
+    resources: SparseSet<ComponentId, ResourceInfo>,
 }
 
 impl Resources {
-    /// Gets the [`ArchetypeComponentId`] for a given resoruce.
-    #[inline]
-    pub fn get_archetype_component_id(
-        &self,
-        component_id: ComponentId,
-    ) -> Option<ArchetypeComponentId> {
-        self.resources
-            .get(component_id)
-            .map(|info| info.component_info.archetype_component_id)
-    }
-
     /// The total number of resoruces stored in the [`World`]
     ///
     /// [`World`]: crate::world::World
@@ -50,85 +125,52 @@ impl Resources {
 
     /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
-    pub fn get(&self, component_id: ComponentId) -> Option<Ptr<'_>> {
-        self.resources.get(component_id)?.data.get_data(0)
+    pub fn get(&self, component_id: ComponentId) -> Option<&ResourceInfo> {
+        self.resources.get(component_id)
     }
 
     /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
-    pub fn get_mut(&mut self, component_id: ComponentId) -> Option<PtrMut<'_>> {
-        self.resources.get_mut(component_id)?.data.get_data_mut(0)
-    }
-
-    /// Gets the [`ComponentTicks`] to a resource, if available.
-    #[inline]
-    pub fn get_ticks(&self, component_id: ComponentId) -> Option<&ComponentTicks> {
-        // SAFE: If row 0 exists, it's ComponentTicks must be valid as well.
-        self.resources
-            .get(component_id)?
-            .data
-            .get_ticks(0)
-            .map(|ticks| unsafe { ticks.deref() })
+    pub fn get_mut(&mut self, component_id: ComponentId) -> Option<&mut ResourceInfo> {
+        self.resources.get_mut(component_id)
     }
 
     /// Checks if the a resource is currently stored with a given ID.
     #[inline]
     pub fn contains(&self, component_id: ComponentId) -> bool {
-        self.resources
-            .get(component_id)
-            .map(|info| !info.data.is_empty())
+        self.get(component_id)
+            .map(|info| info.is_present())
             .unwrap_or(false)
     }
 
-    #[inline]
-    pub(crate) fn get_with_ticks(
-        &self,
-        component_id: ComponentId,
-    ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
-        self.resources.get(component_id)?.data.get(0)
-    }
-
-    /// Inserts a resource into the world.
+    /// Fetches or initializes a new resource and returns back it's underlying column.
     ///
-    /// # Safety
-    /// `data` must point to valid data of this column's component type which
-    /// must correspond to the provided ID.
-    #[inline]
-    pub unsafe fn insert(
+    /// # Panics
+    /// Will panic if `component_id` is not valid for the provided `components`
+    pub fn initialize_with<F>(
         &mut self,
         component_id: ComponentId,
-        data: OwningPtr<'_>,
-        ticks: ComponentTicks,
-    ) -> Option<()> {
-        let column = &mut self.resources.get_mut(component_id)?.data;
-        debug_assert!(column.is_empty());
-        column.push(data, ticks);
-        Some(())
-    }
-
-    /// Removes a resource from the world.
-    ///
-    /// # Safety
-    /// ptr must point to valid data of this column's component type which
-    /// must correspond to the provided ID.
-    #[inline]
-    #[must_use = "The returned pointer to the removed component should be used or dropped"]
-    pub fn remove(&mut self, component_id: ComponentId) -> Option<(OwningPtr<'_>, ComponentTicks)> {
-        self.resources
-            .get_mut(component_id)?
-            .data
-            .swap_remove_and_forget(0)
-    }
-
-    #[inline]
-    pub(crate) fn remove_and_drop(&mut self, component_id: ComponentId) -> Option<()> {
-        let column = &mut self.resources.get_mut(component_id)?.data;
-        (column.len() > 0).then(|| column.clear())
+        components: &Components,
+        f: F,
+    ) -> &mut ResourceInfo
+    where
+        F: FnOnce() -> ArchetypeComponentId,
+    {
+        self.resources.get_or_insert_with(component_id, || {
+            let component_info = components.get_info(component_id).unwrap();
+            ResourceInfo {
+                column: Column::with_capacity(component_info, 1),
+                component_info: ArchetypeComponentInfo {
+                    archetype_component_id: f(),
+                    storage_type: StorageType::Table,
+                },
+            }
+        })
     }
 
     pub fn check_change_ticks(&mut self, change_tick: u32) {
         for info in self.resources.values_mut() {
-            info.data.check_change_ticks(change_tick);
+            info.column.check_change_ticks(change_tick);
         }
     }
 }
diff --git a/crates/bevy_ecs/src/storage/table.rs b/crates/bevy_ecs/src/storage/table.rs
index 965874e4e6df1..480feb038e182 100644
--- a/crates/bevy_ecs/src/storage/table.rs
+++ b/crates/bevy_ecs/src/storage/table.rs
@@ -73,6 +73,18 @@ impl Column {
             .set_changed(change_tick);
     }
 
+    /// Writes component data to the column at given row.
+    /// Assumes the slot is initialized, calls drop.
+    /// Does not update the Component's ticks.
+    ///
+    /// # Safety
+    /// Assumes data has already been allocated for the given row.
+    #[inline]
+    pub(crate) unsafe fn replace_untracked(&mut self, row: usize, data: OwningPtr<'_>) {
+        debug_assert!(row < self.len());
+        self.data.replace_unchecked(row, data);
+    }
+
     /// # Safety
     /// Assumes data has already been allocated for the given row.
     #[inline]
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 0e0a241868c92..d557473579cb2 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -8,15 +8,13 @@ pub use spawn_batch::*;
 pub use world_cell::*;
 
 use crate::{
-    archetype::{ArchetypeComponentId, ArchetypeComponentInfo, ArchetypeId, Archetypes},
+    archetype::{ArchetypeComponentId, ArchetypeId, Archetypes},
     bundle::{Bundle, BundleInserter, BundleSpawner, Bundles},
     change_detection::{MutUntyped, Ticks},
-    component::{
-        Component, ComponentDescriptor, ComponentId, ComponentTicks, Components, StorageType,
-    },
+    component::{Component, ComponentDescriptor, ComponentId, ComponentTicks, Components},
     entity::{AllocAtWithoutReplacement, Entities, Entity},
     query::{QueryState, WorldQuery},
-    storage::{Column, ResourceInfo, SparseSet, Storages},
+    storage::{ResourceInfo, SparseSet, Storages},
     system::Resource,
 };
 use bevy_ptr::{OwningPtr, Ptr, UnsafeCellDeref};
@@ -684,7 +682,7 @@ impl World {
         let component_id = self.components.get_resource_id(TypeId::of::<R>())?;
         // SAFE: the resource is of type R and the value is returned back to the caller.
         unsafe {
-            let (ptr, _) = self.storages.resources.remove(component_id)?;
+            let (ptr, _) = self.storages.resources.get_mut(component_id)?.remove()?;
             Some(ptr.read::<R>())
         }
     }
@@ -701,7 +699,7 @@ impl World {
     pub fn is_resource_added<R: Resource>(&self) -> bool {
         self.components
             .get_resource_id(TypeId::of::<R>())
-            .and_then(|component_id| self.storages.resources.get_ticks(component_id))
+            .and_then(|component_id| self.storages.resources.get(component_id)?.get_ticks())
             .map(|ticks| ticks.is_added(self.last_change_tick(), self.read_change_tick()))
             .unwrap_or(false)
     }
@@ -709,7 +707,7 @@ impl World {
     pub fn is_resource_changed<R: Resource>(&self) -> bool {
         self.components
             .get_resource_id(TypeId::of::<R>())
-            .and_then(|component_id| self.storages.resources.get_ticks(component_id))
+            .and_then(|component_id| self.storages.resources.get(component_id)?.get_ticks())
             .map(|ticks| ticks.is_changed(self.last_change_tick(), self.read_change_tick()))
             .unwrap_or(false)
     }
@@ -878,7 +876,7 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
-        self.storages.resources.get_with_ticks(component_id)
+        self.storages.resources.get(component_id)?.get_with_ticks()
     }
 
     // Shorthand helper function for getting the [`ArchetypeComponentId`] for a resource.
@@ -887,9 +885,8 @@ impl World {
         &self,
         component_id: ComponentId,
     ) -> Option<ArchetypeComponentId> {
-        self.storages
-            .resources
-            .get_archetype_component_id(component_id)
+        let resource = self.storages.resources.get(component_id)?;
+        Some(resource.component_info().archetype_component_id)
     }
 
     /// For a given batch of ([Entity], [Bundle]) pairs, either spawns each [Entity] with the given
@@ -1049,7 +1046,8 @@ impl World {
         let (ptr, mut ticks) = self
             .storages
             .resources
-            .remove(component_id)
+            .get_mut(component_id)
+            .and_then(|info| info.remove())
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
         // SAFE: pointer is of type R
         // Read the value onto the stack to avoid potential mut aliasing.
@@ -1070,7 +1068,8 @@ impl World {
                 // SAFE: pointer is of type R
                 self.storages
                     .resources
-                    .insert(component_id, ptr, ticks)
+                    .get_mut(component_id)
+                    .map(|info| info.insert_with_ticks(ptr, ticks))
                     .unwrap_or_else(|| {
                         panic!("resource does not exist: {}", std::any::type_name::<R>())
                     });
@@ -1089,7 +1088,8 @@ impl World {
     ) -> Option<&R> {
         self.storages
             .resources
-            .get(component_id)
+            .get(component_id)?
+            .get_data()
             .map(|ptr| ptr.deref())
     }
 
@@ -1140,17 +1140,11 @@ impl World {
     #[inline]
     unsafe fn insert_resource_with_id<R>(&mut self, component_id: ComponentId, value: R) {
         let change_tick = self.change_tick();
-        let column = self.initialize_resource_internal(component_id);
-        if column.is_empty() {
-            // SAFE: column is of type R and has been allocated above
-            OwningPtr::make(value, |ptr| {
-                column.push(ptr, ComponentTicks::new(change_tick));
-            });
-        } else {
-            // SAFE: column is of type R and has already been allocated
-            *column.get_data_unchecked_mut(0).deref_mut::<R>() = value;
-            column.get_ticks_unchecked_mut(0).set_changed(change_tick);
-        }
+        // SAFE: column is of type R and has been allocated above
+        OwningPtr::make(value, |ptr| {
+            self.initialize_resource_internal(component_id)
+                .insert(ptr, change_tick);
+        });
     }
 
     /// Inserts a new resource with the given `value`. Will replace the value if it already existed.
@@ -1173,45 +1167,25 @@ impl World {
             )
         });
         // SAFE: component_id is valid, checked by the lines above
-        let column = self.initialize_resource_internal(component_id);
-        if column.is_empty() {
-            // SAFE: column is of type R and has been allocated above
-            column.push(value, ComponentTicks::new(change_tick));
-        } else {
-            let ptr = column.get_data_unchecked_mut(0);
-            std::ptr::copy_nonoverlapping::<u8>(
-                value.as_ptr(),
-                ptr.as_ptr(),
-                column.data.layout().size(),
-            );
-            column.get_ticks_unchecked_mut(0).set_changed(change_tick);
-        }
+        self.initialize_resource_internal(component_id)
+            .insert(value, change_tick);
     }
 
     /// # Safety
     /// `component_id` must be valid for this world
     #[inline]
-    unsafe fn initialize_resource_internal(&mut self, component_id: ComponentId) -> &mut Column {
-        // SAFE: resource archetype always exists
-        let resources = &mut self.storages.resources.resources;
+    unsafe fn initialize_resource_internal(
+        &mut self,
+        component_id: ComponentId,
+    ) -> &mut ResourceInfo {
         let archetype_component_count = &mut self.archetypes.archetype_component_count;
-        let components = &self.components;
-        &mut resources
-            .get_or_insert_with(component_id, || {
-                let component_info = components.get_info_unchecked(component_id);
-                let info = ResourceInfo {
-                    data: Column::with_capacity(component_info, 1),
-                    component_info: ArchetypeComponentInfo {
-                        archetype_component_id: ArchetypeComponentId::new(
-                            *archetype_component_count,
-                        ),
-                        storage_type: StorageType::Table,
-                    },
-                };
+        self.storages
+            .resources
+            .initialize_with(component_id, &self.components, || {
+                let id = ArchetypeComponentId::new(*archetype_component_count);
                 *archetype_component_count += 1;
-                info
+                id
             })
-            .data
     }
 
     pub(crate) fn initialize_resource<R: Resource>(&mut self) -> ComponentId {
@@ -1311,7 +1285,7 @@ impl World {
         if !info.is_send_and_sync() {
             self.validate_non_send_access_untyped(info.name());
         }
-        self.storages.resources.get(component_id)
+        self.storages.resources.get(component_id)?.get_data()
     }
 
     /// Gets a resource to the resource with the id [`ComponentId`] if it exists.
@@ -1352,7 +1326,11 @@ impl World {
         if !info.is_send_and_sync() {
             self.validate_non_send_access_untyped(info.name());
         }
-        self.storages.resources.remove_and_drop(component_id)
+        self.storages
+            .resources
+            .get_mut(component_id)?
+            .remove_and_drop();
+        Some(())
     }
 
     /// Retrieves a mutable untyped reference to the given `entity`'s [Component] of the given [`ComponentId`].

From c1f1133453e1f817c2cde84e84856f744ba8711e Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Wed, 15 Jun 2022 05:17:35 -0700
Subject: [PATCH 21/37] Remove contains

---
 crates/bevy_ecs/src/storage/resource.rs | 8 --------
 crates/bevy_ecs/src/world/mod.rs        | 3 ++-
 2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 31515871e2067..c56a6f3a45835 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -135,14 +135,6 @@ impl Resources {
         self.resources.get_mut(component_id)
     }
 
-    /// Checks if the a resource is currently stored with a given ID.
-    #[inline]
-    pub fn contains(&self, component_id: ComponentId) -> bool {
-        self.get(component_id)
-            .map(|info| info.is_present())
-            .unwrap_or(false)
-    }
-
     /// Fetches or initializes a new resource and returns back it's underlying column.
     ///
     /// # Panics
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index d557473579cb2..ceae72646e6f5 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -692,7 +692,8 @@ impl World {
     pub fn contains_resource<R: 'static>(&self) -> bool {
         self.components
             .get_resource_id(TypeId::of::<R>())
-            .map(|component_id| self.storages.resources.contains(component_id))
+            .and_then(|component_id| self.storages.resources.get(component_id))
+            .map(|info| info.is_present())
             .unwrap_or(false)
     }
 

From f4123b9db9f0c53a4b5173058cde16ce30667c0e Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Sat, 2 Jul 2022 16:42:06 -0700
Subject: [PATCH 22/37] Fix test compilation

---
 crates/bevy_ecs/src/lib.rs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/crates/bevy_ecs/src/lib.rs b/crates/bevy_ecs/src/lib.rs
index 3acbb4bb96350..6c3f189884042 100644
--- a/crates/bevy_ecs/src/lib.rs
+++ b/crates/bevy_ecs/src/lib.rs
@@ -1016,8 +1016,10 @@ mod tests {
         let archetype_component_id = world
             .storages()
             .resources
-            .get_archetype_component_id(resource_id)
-            .unwrap();
+            .get(resource_id)
+            .unwrap()
+            .component_info()
+            .archetype_component_id;
 
         assert_eq!(*world.resource::<i32>(), 123);
         assert!(world.contains_resource::<i32>());
@@ -1083,8 +1085,10 @@ mod tests {
         let current_archetype_component_id = world
             .storages()
             .resources
-            .get_archetype_component_id(current_resource_id)
-            .unwrap();
+            .get(resource_id)
+            .unwrap()
+            .component_info()
+            .archetype_component_id;
 
         assert_eq!(
             archetype_component_id, current_archetype_component_id,

From bb38531187f62d059e10a3d5bb4b8acaa201b797 Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Thu, 13 Oct 2022 14:05:54 -0700
Subject: [PATCH 23/37] Fix must_use typo

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
---
 crates/bevy_ecs/src/storage/table.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/table.rs b/crates/bevy_ecs/src/storage/table.rs
index a709284a8e5ae..124dca6a85ca2 100644
--- a/crates/bevy_ecs/src/storage/table.rs
+++ b/crates/bevy_ecs/src/storage/table.rs
@@ -125,7 +125,7 @@ impl Column {
     }
 
     #[inline]
-    #[must_use = "The returned pointer should be used to dropped the removed component"]
+    #[must_use = "The returned pointer should be used to drop the removed component"]
     pub(crate) fn swap_remove_and_forget(
         &mut self,
         row: usize,

From bb59857cd9b59b987086219df31924c4b323f615 Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Thu, 13 Oct 2022 14:06:15 -0700
Subject: [PATCH 24/37] Change panic message.

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
---
 crates/bevy_ecs/src/world/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 83019a167b4d5..25b9a8afd1728 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -1133,7 +1133,7 @@ impl World {
                     .get_mut(component_id)
                     .map(|info| info.insert_with_ticks(ptr, ticks))
                     .unwrap_or_else(|| {
-                        panic!("resource does not exist: {}", std::any::type_name::<R>())
+                        panic!("No resource of type {} exists in the World.", std::any::type_name::<R>())
                     });
             }
         });

From 3556580c59fb5036cb7b0e49280e815168af0402 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Thu, 13 Oct 2022 14:26:43 -0700
Subject: [PATCH 25/37] ResourceInfo -> ResourceData

---
 crates/bevy_ecs/src/storage/resource.rs | 14 +++++++-------
 crates/bevy_ecs/src/world/mod.rs        |  4 ++--
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index c56a6f3a45835..1db2ac0b10a6e 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -5,12 +5,12 @@ use crate::storage::{Column, SparseSet};
 use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
 use std::cell::UnsafeCell;
 
-pub struct ResourceInfo {
+pub struct ResourceData {
     column: Column,
     component_info: ArchetypeComponentInfo,
 }
 
-impl ResourceInfo {
+impl ResourceData {
     /// Returns true if the resource is populated.
     #[inline]
     pub fn is_present(&self) -> bool {
@@ -102,7 +102,7 @@ impl ResourceInfo {
 /// [`World`]: crate::world::World
 #[derive(Default)]
 pub struct Resources {
-    resources: SparseSet<ComponentId, ResourceInfo>,
+    resources: SparseSet<ComponentId, ResourceData>,
 }
 
 impl Resources {
@@ -125,13 +125,13 @@ impl Resources {
 
     /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
-    pub fn get(&self, component_id: ComponentId) -> Option<&ResourceInfo> {
+    pub fn get(&self, component_id: ComponentId) -> Option<&ResourceData> {
         self.resources.get(component_id)
     }
 
     /// Gets a read-only [`Ptr`] to a resource, if available.
     #[inline]
-    pub fn get_mut(&mut self, component_id: ComponentId) -> Option<&mut ResourceInfo> {
+    pub fn get_mut(&mut self, component_id: ComponentId) -> Option<&mut ResourceData> {
         self.resources.get_mut(component_id)
     }
 
@@ -144,13 +144,13 @@ impl Resources {
         component_id: ComponentId,
         components: &Components,
         f: F,
-    ) -> &mut ResourceInfo
+    ) -> &mut ResourceData
     where
         F: FnOnce() -> ArchetypeComponentId,
     {
         self.resources.get_or_insert_with(component_id, || {
             let component_info = components.get_info(component_id).unwrap();
-            ResourceInfo {
+            ResourceData {
                 column: Column::with_capacity(component_info, 1),
                 component_info: ArchetypeComponentInfo {
                     archetype_component_id: f(),
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 25b9a8afd1728..ce958ea5e3707 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -16,7 +16,7 @@ use crate::{
     },
     entity::{AllocAtWithoutReplacement, Entities, Entity},
     query::{QueryState, WorldQuery},
-    storage::{ResourceInfo, SparseSet, Storages},
+    storage::{ResourceData, SparseSet, Storages},
     system::Resource,
 };
 use bevy_ptr::{OwningPtr, Ptr, UnsafeCellDeref};
@@ -1239,7 +1239,7 @@ impl World {
     unsafe fn initialize_resource_internal(
         &mut self,
         component_id: ComponentId,
-    ) -> &mut ResourceInfo {
+    ) -> &mut ResourceData {
         let archetype_component_count = &mut self.archetypes.archetype_component_count;
         self.storages
             .resources

From 734584d386fa40c7f5769eede3a9b3b892851f13 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Thu, 13 Oct 2022 14:27:52 -0700
Subject: [PATCH 26/37] Type doc comment for ResourceData

---
 crates/bevy_ecs/src/storage/resource.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 1db2ac0b10a6e..2a0305c71134f 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -5,6 +5,7 @@ use crate::storage::{Column, SparseSet};
 use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
 use std::cell::UnsafeCell;
 
+/// The type-erased backing storage and metadata for a single resource within a [`World`].
 pub struct ResourceData {
     column: Column,
     component_info: ArchetypeComponentInfo,

From 58027c4bbe4cf968e83262ac1979613bdafa7669 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Sat, 15 Oct 2022 22:19:06 -0700
Subject: [PATCH 27/37] Fix CI

---
 crates/bevy_ecs/src/storage/resource.rs | 5 +++++
 crates/bevy_ecs/src/storage/table.rs    | 6 +++---
 crates/bevy_ecs/src/world/mod.rs        | 6 +++---
 crates/bevy_ecs/src/world/world_cell.rs | 5 +----
 4 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 21bc70e8f956e..44f178c8c14f6 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -6,6 +6,8 @@ use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
 use std::cell::UnsafeCell;
 
 /// The type-erased backing storage and metadata for a single resource within a [`World`].
+///
+/// [`World`]: crate::world::World
 pub struct ResourceData {
     column: Column,
     component_info: ArchetypeComponentInfo,
@@ -40,6 +42,7 @@ impl ResourceData {
     pub fn get_ticks(&self) -> Option<&ComponentTicks> {
         self.column
             .get_ticks(0)
+            // SAFETY: If the first row exists, a valid ticks value has been written.
             .map(|ticks| unsafe { ticks.deref() })
     }
 
@@ -48,6 +51,8 @@ impl ResourceData {
     pub fn get_ticks_mut(&mut self) -> Option<&mut ComponentTicks> {
         self.column
             .get_ticks(0)
+            // SAFETY: If the first row exists, a valid ticks value has been written.
+            // This function has exclusvie access to the underlying column.
             .map(|ticks| unsafe { ticks.deref_mut() })
     }
 
diff --git a/crates/bevy_ecs/src/storage/table.rs b/crates/bevy_ecs/src/storage/table.rs
index 00fe5931c638b..d826b1c306575 100644
--- a/crates/bevy_ecs/src/storage/table.rs
+++ b/crates/bevy_ecs/src/storage/table.rs
@@ -122,7 +122,7 @@ impl Column {
         &mut self,
         row: usize,
     ) -> Option<(OwningPtr<'_>, ComponentTicks)> {
-        (row > self.data.len()).then(|| {
+        (row < self.data.len()).then(|| {
             // SAFETY: The row was length checked before this.
             let data = unsafe { self.data.swap_remove_and_forget_unchecked(row) };
             let ticks = self.ticks.swap_remove(row).into_inner();
@@ -198,9 +198,9 @@ impl Column {
 
     #[inline]
     pub fn get(&self, row: usize) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
-        // SAFETY: The row is length checked before fetching the pointer. This is being
-        // accessed through a read-only reference to the column.
         (row < self.data.len())
+            // SAFETY: The row is length checked before fetching the pointer. This is being
+            // accessed through a read-only reference to the column.
             .then(|| unsafe { (self.data.get_unchecked(row), self.ticks.get_unchecked(row)) })
     }
 
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 2120048bfc5bc..5ee25dc319580 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -786,7 +786,7 @@ impl World {
     #[allow(unused_unsafe)]
     pub unsafe fn remove_resource_unchecked<R: 'static>(&mut self) -> Option<R> {
         let component_id = self.components.get_resource_id(TypeId::of::<R>())?;
-        // SAFE: the resource is of type R and the value is returned back to the caller.
+        // SAFETY: the resource is of type R and the value is returned back to the caller.
         unsafe {
             let (ptr, _) = self.storages.resources.get_mut(component_id)?.remove()?;
             Some(ptr.read::<R>())
@@ -1169,7 +1169,7 @@ impl World {
             .and_then(|info| info.remove())
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
         // Read the value onto the stack to avoid potential mut aliasing.
-        // SAFE: pointer is of type R
+        // SAFETY: pointer is of type R
         let mut value = unsafe { ptr.read::<R>() };
         let value_mut = Mut {
             value: &mut value,
@@ -1448,7 +1448,7 @@ impl World {
         };
 
         Some(MutUntyped {
-            // SAFE: This function has exclusive access to the world so nothing aliases `ptr`.
+            // SAFETY: This function has exclusive access to the world so nothing aliases `ptr`.
             value: unsafe { ptr.assert_unique() },
             ticks,
         })
diff --git a/crates/bevy_ecs/src/world/world_cell.rs b/crates/bevy_ecs/src/world/world_cell.rs
index 0d4ccbf677a39..71c8216b24939 100644
--- a/crates/bevy_ecs/src/world/world_cell.rs
+++ b/crates/bevy_ecs/src/world/world_cell.rs
@@ -381,10 +381,7 @@ mod tests {
             }
         }
 
-        let u32_component_id = world
-            .components
-            .get_resource_id(TypeId::of::<u32>())
-            .unwrap();
+        let u32_component_id = world.components.get_resource_id(TypeId::of::<A>()).unwrap();
         let u32_archetype_component_id = world
             .get_resource_archetype_component_id(u32_component_id)
             .unwrap();

From d3d846aa0ae0b27376c8a64173ecfbb628d5ba8f Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Sun, 16 Oct 2022 16:11:57 -0700
Subject: [PATCH 28/37] Update get's doc comment.

Co-authored-by: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
---
 crates/bevy_ecs/src/storage/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 44f178c8c14f6..68355d456c6c4 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -129,7 +129,7 @@ impl Resources {
         self.resources.is_empty()
     }
 
-    /// Gets a read-only [`Ptr`] to a resource, if available.
+    /// Gets read-only access to a resource, if it exists.
     #[inline]
     pub fn get(&self, component_id: ComponentId) -> Option<&ResourceData> {
         self.resources.get(component_id)

From 40afd474408172062bd52eaacd8803283214799d Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Sun, 16 Oct 2022 16:12:12 -0700
Subject: [PATCH 29/37] Update get_mut's doc comment.

Co-authored-by: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
---
 crates/bevy_ecs/src/storage/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 68355d456c6c4..92592ac5a3d4f 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -135,7 +135,7 @@ impl Resources {
         self.resources.get(component_id)
     }
 
-    /// Gets a read-only [`Ptr`] to a resource, if available.
+    /// Gets mutable access to a resource, if it exists.
     #[inline]
     pub fn get_mut(&mut self, component_id: ComponentId) -> Option<&mut ResourceData> {
         self.resources.get_mut(component_id)

From 7b9fbf0e85d6f33fa9abf05f031fea3a5f580bea Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 09:09:52 -0700
Subject: [PATCH 30/37] Fix docs typo

Co-authored-by: Boxy <supbscripter@gmail.com>
---
 crates/bevy_ecs/src/storage/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 92592ac5a3d4f..01b37c1594919 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -112,7 +112,7 @@ pub struct Resources {
 }
 
 impl Resources {
-    /// The total number of resoruces stored in the [`World`]
+    /// The total number of resources stored in the [`World`]
     ///
     /// [`World`]: crate::world::World
     #[inline]

From a6c897708a223d788ba7ea56dc87f6b3e225aa8b Mon Sep 17 00:00:00 2001
From: James Liu <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 09:11:14 -0700
Subject: [PATCH 31/37] Use an impl param instead of a bound

Co-authored-by: Boxy <supbscripter@gmail.com>
---
 crates/bevy_ecs/src/storage/resource.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 01b37c1594919..570ef468f1279 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -149,10 +149,8 @@ impl Resources {
         &mut self,
         component_id: ComponentId,
         components: &Components,
-        f: F,
-    ) -> &mut ResourceData
-    where
-        F: FnOnce() -> ArchetypeComponentId,
+        f: impl FnOnce() -> ArchetypeComponentId,
+    ) -> &mut ResourceData,
     {
         self.resources.get_or_insert_with(component_id, || {
             let component_info = components.get_info(component_id).unwrap();

From 39be822b961c480b40b47c86011afad58ceae57f Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 16:46:06 -0700
Subject: [PATCH 32/37] ArchetypeComponentInfo -> Id

---
 crates/bevy_ecs/src/storage/resource.rs | 15 ++++++---------
 crates/bevy_ecs/src/world/mod.rs        |  2 +-
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 570ef468f1279..d13a431941dc2 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -1,6 +1,5 @@
 use crate::archetype::ArchetypeComponentId;
-use crate::archetype::ArchetypeComponentInfo;
-use crate::component::{ComponentId, ComponentTicks, Components, StorageType};
+use crate::component::{ComponentId, ComponentTicks, Components};
 use crate::storage::{Column, SparseSet};
 use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
 use std::cell::UnsafeCell;
@@ -10,7 +9,7 @@ use std::cell::UnsafeCell;
 /// [`World`]: crate::world::World
 pub struct ResourceData {
     column: Column,
-    component_info: ArchetypeComponentInfo,
+    id: ArchetypeComponentId,
 }
 
 impl ResourceData {
@@ -20,9 +19,10 @@ impl ResourceData {
         !self.column.is_empty()
     }
 
+    /// Gets the [`ArchetypeComponentId`] for the resource.
     #[inline]
-    pub(crate) fn component_info(&self) -> &ArchetypeComponentInfo {
-        &self.component_info
+    pub fn id(&self) -> ArchetypeComponentId {
+        self.id
     }
 
     /// Gets a read-only pointer to the underlying resource, if available.
@@ -156,10 +156,7 @@ impl Resources {
             let component_info = components.get_info(component_id).unwrap();
             ResourceData {
                 column: Column::with_capacity(component_info, 1),
-                component_info: ArchetypeComponentInfo {
-                    archetype_component_id: f(),
-                    storage_type: StorageType::Table,
-                },
+                id: f(),
             }
         })
     }
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index 5ee25dc319580..e4778b3ca51ae 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -993,7 +993,7 @@ impl World {
         component_id: ComponentId,
     ) -> Option<ArchetypeComponentId> {
         let resource = self.storages.resources.get(component_id)?;
-        Some(resource.component_info().archetype_component_id)
+        Some(resource.id())
     }
 
     /// For a given batch of ([Entity], [Bundle]) pairs, either spawns each [Entity] with the given

From efd51137dd89596d9eb2c0f2c856e20118e89641 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 19:14:11 -0700
Subject: [PATCH 33/37] Remove public access to data methods

---
 crates/bevy_ecs/src/storage/resource.rs | 31 ++++++-------------------
 1 file changed, 7 insertions(+), 24 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index d13a431941dc2..a4da1c8419458 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -1,7 +1,7 @@
 use crate::archetype::ArchetypeComponentId;
 use crate::component::{ComponentId, ComponentTicks, Components};
 use crate::storage::{Column, SparseSet};
-use bevy_ptr::{OwningPtr, Ptr, PtrMut, UnsafeCellDeref};
+use bevy_ptr::{OwningPtr, Ptr, UnsafeCellDeref};
 use std::cell::UnsafeCell;
 
 /// The type-erased backing storage and metadata for a single resource within a [`World`].
@@ -31,12 +31,6 @@ impl ResourceData {
         self.column.get_data(0)
     }
 
-    /// Gets a mutable pointer to the underlying resource, if available.
-    #[inline]
-    pub fn get_data_mut(&mut self) -> Option<PtrMut<'_>> {
-        self.column.get_data_mut(0)
-    }
-
     /// Gets a read-only reference to the change ticks of the underlying resource, if available.
     #[inline]
     pub fn get_ticks(&self) -> Option<&ComponentTicks> {
@@ -46,16 +40,6 @@ impl ResourceData {
             .map(|ticks| unsafe { ticks.deref() })
     }
 
-    /// Gets a mutable reference to the change ticks of the underlying resource, if available.
-    #[inline]
-    pub fn get_ticks_mut(&mut self) -> Option<&mut ComponentTicks> {
-        self.column
-            .get_ticks(0)
-            // SAFETY: If the first row exists, a valid ticks value has been written.
-            // This function has exclusvie access to the underlying column.
-            .map(|ticks| unsafe { ticks.deref_mut() })
-    }
-
     #[inline]
     pub(crate) fn get_with_ticks(&self) -> Option<(Ptr<'_>, &UnsafeCell<ComponentTicks>)> {
         self.column.get(0)
@@ -67,7 +51,7 @@ impl ResourceData {
     /// # Safety
     /// `value` must be valid for the underlying type for the resource.
     #[inline]
-    pub unsafe fn insert(&mut self, value: OwningPtr<'_>, change_tick: u32) {
+    pub(crate) unsafe fn insert(&mut self, value: OwningPtr<'_>, change_tick: u32) {
         if self.is_present() {
             self.column.replace(0, value, change_tick);
         } else {
@@ -92,7 +76,7 @@ impl ResourceData {
     /// Removes a value from the resource, if present.
     #[inline]
     #[must_use = "The returned pointer to the removed component should be used or dropped"]
-    pub fn remove(&mut self) -> Option<(OwningPtr<'_>, ComponentTicks)> {
+    pub(crate) fn remove(&mut self) -> Option<(OwningPtr<'_>, ComponentTicks)> {
         self.column.swap_remove_and_forget(0)
     }
 
@@ -137,7 +121,7 @@ impl Resources {
 
     /// Gets mutable access to a resource, if it exists.
     #[inline]
-    pub fn get_mut(&mut self, component_id: ComponentId) -> Option<&mut ResourceData> {
+    pub(crate) fn get_mut(&mut self, component_id: ComponentId) -> Option<&mut ResourceData> {
         self.resources.get_mut(component_id)
     }
 
@@ -145,13 +129,12 @@ impl Resources {
     ///
     /// # Panics
     /// Will panic if `component_id` is not valid for the provided `components`
-    pub fn initialize_with<F>(
+    pub(crate) fn initialize_with(
         &mut self,
         component_id: ComponentId,
         components: &Components,
         f: impl FnOnce() -> ArchetypeComponentId,
-    ) -> &mut ResourceData,
-    {
+    ) -> &mut ResourceData {
         self.resources.get_or_insert_with(component_id, || {
             let component_info = components.get_info(component_id).unwrap();
             ResourceData {
@@ -161,7 +144,7 @@ impl Resources {
         })
     }
 
-    pub fn check_change_ticks(&mut self, change_tick: u32) {
+    pub(crate) fn check_change_ticks(&mut self, change_tick: u32) {
         for info in self.resources.values_mut() {
             info.column.check_change_ticks(change_tick);
         }

From 535bc9f565898f41735877027e871152fdb7a112 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 19:25:44 -0700
Subject: [PATCH 34/37] Update safety comments on mutative resource APIs

---
 crates/bevy_ecs/src/storage/resource.rs | 26 +++++++++++++++++++++++--
 crates/bevy_ecs/src/world/mod.rs        | 14 ++++++++-----
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index a4da1c8419458..8f11a772dc27e 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -50,6 +50,9 @@ impl ResourceData {
     ///
     /// # Safety
     /// `value` must be valid for the underlying type for the resource.
+    ///
+    /// The underlying type must be [`Send`] or be inserted from the main thread.
+    /// This can be validated with [`World::validate_non_send_access_untyped`].
     #[inline]
     pub(crate) unsafe fn insert(&mut self, value: OwningPtr<'_>, change_tick: u32) {
         if self.is_present() {
@@ -59,6 +62,14 @@ impl ResourceData {
         }
     }
 
+    /// Inserts a value into the resource with a pre-existing change tick. If a
+    /// value is already present it will be replaced.
+    ///
+    /// # Safety
+    /// `value` must be valid for the underlying type for the resource.
+    ///
+    /// The underlying type must be [`Send`] or be inserted from the main thread.
+    /// This can be validated with [`World::validate_non_send_access_untyped`].
     #[inline]
     pub(crate) unsafe fn insert_with_ticks(
         &mut self,
@@ -74,14 +85,25 @@ impl ResourceData {
     }
 
     /// Removes a value from the resource, if present.
+    ///
+    /// # Safety
+    /// The underlying type must be [`Send`] or be removed from the main thread.
+    /// This can be validated with [`World::validate_non_send_access_untyped`].
+    ///
+    /// The removed value must be used or dropped.
     #[inline]
     #[must_use = "The returned pointer to the removed component should be used or dropped"]
-    pub(crate) fn remove(&mut self) -> Option<(OwningPtr<'_>, ComponentTicks)> {
+    pub(crate) unsafe fn remove(&mut self) -> Option<(OwningPtr<'_>, ComponentTicks)> {
         self.column.swap_remove_and_forget(0)
     }
 
+    /// Removes a value from the resource, if present, and drops it.
+    ///
+    /// # Safety
+    /// The underlying type must be [`Send`] or be removed from the main thread.
+    /// This can be validated with [`World::validate_non_send_access_untyped`].
     #[inline]
-    pub(crate) fn remove_and_drop(&mut self) {
+    pub(crate) unsafe fn remove_and_drop(&mut self) {
         self.column.clear();
     }
 }
diff --git a/crates/bevy_ecs/src/world/mod.rs b/crates/bevy_ecs/src/world/mod.rs
index e4778b3ca51ae..6ae591d355001 100644
--- a/crates/bevy_ecs/src/world/mod.rs
+++ b/crates/bevy_ecs/src/world/mod.rs
@@ -1166,7 +1166,8 @@ impl World {
             .storages
             .resources
             .get_mut(component_id)
-            .and_then(|info| info.remove())
+            // SAFETY: The type R is Send and Sync or we've already validated that we're on the main thread.
+            .and_then(|info| unsafe { info.remove() })
             .unwrap_or_else(|| panic!("resource does not exist: {}", std::any::type_name::<R>()));
         // Read the value onto the stack to avoid potential mut aliasing.
         // SAFETY: pointer is of type R
@@ -1463,10 +1464,13 @@ impl World {
         if !info.is_send_and_sync() {
             self.validate_non_send_access_untyped(info.name());
         }
-        self.storages
-            .resources
-            .get_mut(component_id)?
-            .remove_and_drop();
+        // SAFETY: The underlying type is Send and Sync or we've already validated we're on the main thread
+        unsafe {
+            self.storages
+                .resources
+                .get_mut(component_id)?
+                .remove_and_drop();
+        }
         Some(())
     }
 

From 7932fa8d4d013f45ff69173ec2340236267f0895 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 19:49:24 -0700
Subject: [PATCH 35/37] Fix CI

---
 crates/bevy_ecs/src/lib.rs              | 17 +++--------------
 crates/bevy_ecs/src/storage/resource.rs |  8 ++++++++
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/crates/bevy_ecs/src/lib.rs b/crates/bevy_ecs/src/lib.rs
index ac23368390e8e..8dd9a7bf5e1c7 100644
--- a/crates/bevy_ecs/src/lib.rs
+++ b/crates/bevy_ecs/src/lib.rs
@@ -956,13 +956,7 @@ mod tests {
             .components()
             .get_resource_id(TypeId::of::<Num>())
             .unwrap();
-        let archetype_component_id = world
-            .storages()
-            .resources
-            .get(resource_id)
-            .unwrap()
-            .component_info()
-            .archetype_component_id;
+        let archetype_component_id = world.storages().resources.get(resource_id).unwrap().id();
 
         assert_eq!(world.resource::<Num>().0, 123);
         assert!(world.contains_resource::<Num>());
@@ -1025,13 +1019,8 @@ mod tests {
             "resource id does not change after removing / re-adding"
         );
 
-        let current_archetype_component_id = world
-            .storages()
-            .resources
-            .get(resource_id)
-            .unwrap()
-            .component_info()
-            .archetype_component_id;
+        let current_archetype_component_id =
+            world.storages().resources.get(resource_id).unwrap().id();
 
         assert_eq!(
             archetype_component_id, current_archetype_component_id,
diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 8f11a772dc27e..4fdad1dbfbba3 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -53,6 +53,8 @@ impl ResourceData {
     ///
     /// The underlying type must be [`Send`] or be inserted from the main thread.
     /// This can be validated with [`World::validate_non_send_access_untyped`].
+    ///
+    /// [`World::validate_non_send_access_untyped`]: crate::world::World::validate_non_send_access_untyped
     #[inline]
     pub(crate) unsafe fn insert(&mut self, value: OwningPtr<'_>, change_tick: u32) {
         if self.is_present() {
@@ -70,6 +72,8 @@ impl ResourceData {
     ///
     /// The underlying type must be [`Send`] or be inserted from the main thread.
     /// This can be validated with [`World::validate_non_send_access_untyped`].
+    ///
+    /// [`World::validate_non_send_access_untyped`]: crate::world::World::validate_non_send_access_untyped
     #[inline]
     pub(crate) unsafe fn insert_with_ticks(
         &mut self,
@@ -91,6 +95,8 @@ impl ResourceData {
     /// This can be validated with [`World::validate_non_send_access_untyped`].
     ///
     /// The removed value must be used or dropped.
+    ///
+    /// [`World::validate_non_send_access_untyped`]: crate::world::World::validate_non_send_access_untyped
     #[inline]
     #[must_use = "The returned pointer to the removed component should be used or dropped"]
     pub(crate) unsafe fn remove(&mut self) -> Option<(OwningPtr<'_>, ComponentTicks)> {
@@ -102,6 +108,8 @@ impl ResourceData {
     /// # Safety
     /// The underlying type must be [`Send`] or be removed from the main thread.
     /// This can be validated with [`World::validate_non_send_access_untyped`].
+    ///
+    /// [`World::validate_non_send_access_untyped`]: crate::world::World::validate_non_send_access_untyped
     #[inline]
     pub(crate) unsafe fn remove_and_drop(&mut self) {
         self.column.clear();

From c2476ed9976654a9d1957e617b11aad561655b00 Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 19:53:34 -0700
Subject: [PATCH 36/37] Update safety docs on get_ticks

---
 crates/bevy_ecs/src/storage/resource.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index 4fdad1dbfbba3..f981eb188e10e 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -36,7 +36,10 @@ impl ResourceData {
     pub fn get_ticks(&self) -> Option<&ComponentTicks> {
         self.column
             .get_ticks(0)
-            // SAFETY: If the first row exists, a valid ticks value has been written.
+            // SAFETY: 
+            //  - This borrow's lifetime is bounded by the lifetime on self.
+            //  - A read-only borrow on self can only exist while a mutable borrow doesn't 
+            //    exist.
             .map(|ticks| unsafe { ticks.deref() })
     }
 

From 31cd2b401c52ac8b4e2cf012691a3b63d84fd1ed Mon Sep 17 00:00:00 2001
From: james7132 <contact@jamessliu.com>
Date: Mon, 17 Oct 2022 20:08:24 -0700
Subject: [PATCH 37/37] Formatting

---
 crates/bevy_ecs/src/storage/resource.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/bevy_ecs/src/storage/resource.rs b/crates/bevy_ecs/src/storage/resource.rs
index f981eb188e10e..edfa51e12857a 100644
--- a/crates/bevy_ecs/src/storage/resource.rs
+++ b/crates/bevy_ecs/src/storage/resource.rs
@@ -36,9 +36,9 @@ impl ResourceData {
     pub fn get_ticks(&self) -> Option<&ComponentTicks> {
         self.column
             .get_ticks(0)
-            // SAFETY: 
+            // SAFETY:
             //  - This borrow's lifetime is bounded by the lifetime on self.
-            //  - A read-only borrow on self can only exist while a mutable borrow doesn't 
+            //  - A read-only borrow on self can only exist while a mutable borrow doesn't
             //    exist.
             .map(|ticks| unsafe { ticks.deref() })
     }