packages/yew/src/html/component/lifecycle.rs

//! Component lifecycle module

use std::any::Any;
use std::rc::Rc;

#[cfg(feature = "csr")]
use web_sys::Element;

use super::scope::{AnyScope, Scope};
use super::BaseComponent;
#[cfg(feature = "hydration")]
use crate::dom_bundle::Fragment;
#[cfg(feature = "csr")]
use crate::dom_bundle::{BSubtree, Bundle};
#[cfg(feature = "csr")]
use crate::html::NodeRef;
#[cfg(feature = "hydration")]
use crate::html::RenderMode;
use crate::html::{Html, RenderError};
use crate::scheduler::{self, Runnable, Shared};
use crate::suspense::{BaseSuspense, Suspension};
use crate::{Callback, Context, HtmlResult};

pub(crate) enum ComponentRenderState {
    #[cfg(feature = "csr")]
    Render {
        bundle: Bundle,
        root: BSubtree,
        parent: Element,
        next_sibling: NodeRef,
        node_ref: NodeRef,
    },
    #[cfg(feature = "hydration")]
    Hydration {
        parent: Element,
        next_sibling: NodeRef,
        node_ref: NodeRef,
        root: BSubtree,
        fragment: Fragment,
    },

    #[cfg(feature = "ssr")]
    Ssr {
        sender: Option<futures::channel::oneshot::Sender<Html>>,
    },
}

impl std::fmt::Debug for ComponentRenderState {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            #[cfg(feature = "csr")]
            Self::Render {
                ref bundle,
                root,
                ref parent,
                ref next_sibling,
                ref node_ref,
            } => f
                .debug_struct("ComponentRenderState::Render")
                .field("bundle", bundle)
                .field("root", root)
                .field("parent", parent)
                .field("next_sibling", next_sibling)
                .field("node_ref", node_ref)
                .finish(),

            #[cfg(feature = "hydration")]
            Self::Hydration {
                ref fragment,
                ref parent,
                ref next_sibling,
                ref node_ref,
                ref root,
            } => f
                .debug_struct("ComponentRenderState::Hydration")
                .field("fragment", fragment)
                .field("root", root)
                .field("parent", parent)
                .field("next_sibling", next_sibling)
                .field("node_ref", node_ref)
                .finish(),

            #[cfg(feature = "ssr")]
            Self::Ssr { ref sender } => {
                let sender_repr = match sender {
                    Some(_) => "Some(_)",
                    None => "None",
                };

                f.debug_struct("ComponentRenderState::Ssr")
                    .field("sender", &sender_repr)
                    .finish()
            }
        }
    }
}

#[cfg(feature = "csr")]
impl ComponentRenderState {
    pub(crate) fn shift(&mut self, next_parent: Element, next_next_sibling: NodeRef) {
        match self {
            #[cfg(feature = "csr")]
            Self::Render {
                bundle,
                parent,
                next_sibling,
                ..
            } => {
                bundle.shift(&next_parent, next_next_sibling.clone());

                *parent = next_parent;
                *next_sibling = next_next_sibling;
            }
            #[cfg(feature = "hydration")]
            Self::Hydration {
                fragment,
                parent,
                next_sibling,
                ..
            } => {
                fragment.shift(&next_parent, next_next_sibling.clone());

                *parent = next_parent;
                *next_sibling = next_next_sibling;
            }

            #[cfg(feature = "ssr")]
            Self::Ssr { .. } => {
                #[cfg(debug_assertions)]
                panic!("shifting is not possible during SSR");
            }
        }
    }
}

struct CompStateInner<COMP>
where
    COMP: BaseComponent,
{
    pub(crate) component: COMP,
    pub(crate) context: Context<COMP>,
}

/// A trait to provide common,
/// generic free behaviour across all components to reduce code size.
///
/// Mostly a thin wrapper that passes the context to a component's lifecycle
/// methods.
pub(crate) trait Stateful {
    fn view(&self) -> HtmlResult;
    fn rendered(&mut self, first_render: bool);
    fn destroy(&mut self);

    fn any_scope(&self) -> AnyScope;

    fn flush_messages(&mut self) -> bool;
    fn props_changed(&mut self, props: Rc<dyn Any>) -> bool;

    fn as_any(&self) -> &dyn Any;
    fn as_any_mut(&mut self) -> &mut dyn Any;
}

impl<COMP> Stateful for CompStateInner<COMP>
where
    COMP: BaseComponent,
{
    fn view(&self) -> HtmlResult {
        self.component.view(&self.context)
    }

    fn rendered(&mut self, first_render: bool) {
        self.component.rendered(&self.context, first_render)
    }

    fn destroy(&mut self) {
        self.component.destroy(&self.context);
    }

    fn any_scope(&self) -> AnyScope {
        self.context.link().clone().into()
    }

    fn flush_messages(&mut self) -> bool {
        self.context
            .link()
            .pending_messages
            .drain()
            .into_iter()
            .fold(false, |acc, msg| {
                self.component.update(&self.context, msg) || acc
            })
    }

    fn props_changed(&mut self, props: Rc<dyn Any>) -> bool {
        let props = match Rc::downcast::<COMP::Properties>(props) {
            Ok(m) => m,
            _ => return false,
        };

        if self.context.props != props {
            self.context.props = props;
            self.component.changed(&self.context)
        } else {
            false
        }
    }

    fn as_any(&self) -> &dyn Any {
        self
    }

    fn as_any_mut(&mut self) -> &mut dyn Any {
        self
    }
}

pub(crate) struct ComponentState {
    pub(super) inner: Box<dyn Stateful>,

    pub(super) render_state: ComponentRenderState,

    #[cfg(feature = "csr")]
    has_rendered: bool,
    #[cfg(feature = "csr")]
    pending_props: Option<Rc<dyn Any>>,

    suspension: Option<Suspension>,

    pub(crate) comp_id: usize,
}

impl ComponentState {
    pub(crate) fn new<COMP: BaseComponent>(
        initial_render_state: ComponentRenderState,
        scope: Scope<COMP>,
        props: Rc<COMP::Properties>,
    ) -> Self {
        let comp_id = scope.id;
        #[cfg(feature = "hydration")]
        let mode = {
            match initial_render_state {
                ComponentRenderState::Render { .. } => RenderMode::Render,
                ComponentRenderState::Hydration { .. } => RenderMode::Hydration,
                #[cfg(feature = "ssr")]
                ComponentRenderState::Ssr { .. } => RenderMode::Ssr,
            }
        };

        let context = Context {
            scope,
            props,
            #[cfg(feature = "hydration")]
            mode,
        };

        let inner = Box::new(CompStateInner {
            component: COMP::create(&context),
            context,
        });

        Self {
            inner,
            render_state: initial_render_state,
            suspension: None,

            #[cfg(feature = "csr")]
            has_rendered: false,
            #[cfg(feature = "csr")]
            pending_props: None,

            comp_id,
        }
    }

    pub(crate) fn downcast_comp_ref<COMP>(&self) -> Option<&COMP>
    where
        COMP: BaseComponent + 'static,
    {
        self.inner
            .as_any()
            .downcast_ref::<CompStateInner<COMP>>()
            .map(|m| &m.component)
    }
}

pub(crate) struct CreateRunner<COMP: BaseComponent> {
    pub initial_render_state: ComponentRenderState,
    pub props: Rc<COMP::Properties>,
    pub scope: Scope<COMP>,
}

impl<COMP: BaseComponent> Runnable for CreateRunner<COMP> {
    fn run(self: Box<Self>) {
        let mut current_state = self.scope.state.borrow_mut();
        if current_state.is_none() {
            #[cfg(debug_assertions)]
            super::log_event(self.scope.id, "create");

            *current_state = Some(ComponentState::new(
                self.initial_render_state,
                self.scope.clone(),
                self.props,
            ));
        }
    }
}

#[cfg(feature = "csr")]
pub(crate) struct PropsUpdateRunner {
    pub props: Rc<dyn Any>,
    pub state: Shared<Option<ComponentState>>,
    pub next_sibling: Option<NodeRef>,
}

#[cfg(feature = "csr")]
impl Runnable for PropsUpdateRunner {
    fn run(self: Box<Self>) {
        let Self {
            next_sibling,
            props,
            state: shared_state,
        } = *self;

        if let Some(state) = shared_state.borrow_mut().as_mut() {
            let next_sibling_changed = match next_sibling {
                Some(next_sibling) => {
                    match state.render_state {
                        #[cfg(feature = "csr")]
                        ComponentRenderState::Render {
                            next_sibling: ref mut current_next_sibling,
                            ..
                        } => {
                            let changed = current_next_sibling.get() != next_sibling.get();
                            // When components are updated, their siblings were likely also updated
                            *current_next_sibling = next_sibling;

                            changed
                        }

                        #[cfg(feature = "hydration")]
                        ComponentRenderState::Hydration {
                            next_sibling: ref mut current_next_sibling,
                            ..
                        } => {
                            let changed = current_next_sibling.get() != next_sibling.get();

                            // When components are updated, their siblings were likely also updated
                            *current_next_sibling = next_sibling;

                            changed
                        }

                        #[cfg(feature = "ssr")]
                        ComponentRenderState::Ssr { .. } => {
                            #[cfg(debug_assertions)]
                            panic!("properties do not change during SSR");

                            #[cfg(not(debug_assertions))]
                            false
                        }
                    }
                }
                None => false,
            };

            // Only trigger changed if props were changed / next sibling has changed.
            let schedule_render = if state.has_rendered {
                state.inner.props_changed(props) || next_sibling_changed
            } else {
                state.pending_props = Some(props);
                next_sibling_changed
            };

            #[cfg(debug_assertions)]
            super::log_event(
                state.comp_id,
                format!(
                    "props_update(has_rendered={} schedule_render={})",
                    state.has_rendered, schedule_render
                ),
            );

            if schedule_render {
                scheduler::push_component_render(
                    state.comp_id,
                    Box::new(RenderRunner {
                        state: shared_state.clone(),
                    }),
                );
                // Only run from the scheduler, so no need to call `scheduler::start()`
            }
        };
    }
}

pub(crate) struct UpdateRunner {
    pub state: Shared<Option<ComponentState>>,
}

impl Runnable for UpdateRunner {
    fn run(self: Box<Self>) {
        if let Some(state) = self.state.borrow_mut().as_mut() {
            let schedule_render = state.inner.flush_messages();

            #[cfg(debug_assertions)]
            super::log_event(
                state.comp_id,
                format!("update(schedule_render={})", schedule_render),
            );

            if schedule_render {
                scheduler::push_component_render(
                    state.comp_id,
                    Box::new(RenderRunner {
                        state: self.state.clone(),
                    }),
                );
                // Only run from the scheduler, so no need to call `scheduler::start()`
            }
        }
    }
}

pub(crate) struct DestroyRunner {
    pub state: Shared<Option<ComponentState>>,

    #[cfg(feature = "csr")]
    pub parent_to_detach: bool,
}

impl Runnable for DestroyRunner {
    fn run(self: Box<Self>) {
        if let Some(mut state) = self.state.borrow_mut().take() {
            #[cfg(debug_assertions)]
            super::log_event(state.comp_id, "destroy");

            state.inner.destroy();

            match state.render_state {
                #[cfg(feature = "csr")]
                ComponentRenderState::Render {
                    bundle,
                    ref parent,
                    ref node_ref,
                    ref root,
                    ..
                } => {
                    bundle.detach(root, parent, self.parent_to_detach);

                    node_ref.set(None);
                }
                // We need to detach the hydrate fragment if the component is not hydrated.
                #[cfg(feature = "hydration")]
                ComponentRenderState::Hydration {
                    ref root,
                    fragment,
                    ref parent,
                    ref node_ref,
                    ..
                } => {
                    fragment.detach(root, parent, self.parent_to_detach);

                    node_ref.set(None);
                }

                #[cfg(feature = "ssr")]
                ComponentRenderState::Ssr { .. } => {}
            }
        }
    }
}

pub(crate) struct RenderRunner {
    pub state: Shared<Option<ComponentState>>,
}

impl Runnable for RenderRunner {
    fn run(self: Box<Self>) {
        if let Some(state) = self.state.borrow_mut().as_mut() {
            #[cfg(debug_assertions)]
            super::log_event(state.comp_id, "render");

            match state.inner.view() {
                Ok(m) => self.render(state, m),
                Err(RenderError::Suspended(m)) => self.suspend(state, m),
            };
        }
    }
}

impl RenderRunner {
    fn suspend(&self, state: &mut ComponentState, suspension: Suspension) {
        // Currently suspended, we re-use previous root node and send
        // suspension to parent element.
        let shared_state = self.state.clone();

        let comp_id = state.comp_id;

        if suspension.resumed() {
            // schedule a render immediately if suspension is resumed.
            scheduler::push_component_render(
                comp_id,
                Box::new(RenderRunner {
                    state: shared_state,
                }),
            );
        } else {
            // We schedule a render after current suspension is resumed.
            let comp_scope = state.inner.any_scope();

            let suspense_scope = comp_scope
                .find_parent_scope::<BaseSuspense>()
                .expect("To suspend rendering, a <Suspense /> component is required.");
            let suspense = suspense_scope.get_component().unwrap();

            suspension.listen(Callback::from(move |_| {
                scheduler::push_component_render(
                    comp_id,
                    Box::new(RenderRunner {
                        state: shared_state.clone(),
                    }),
                );
                scheduler::start();
            }));

            if let Some(ref last_suspension) = state.suspension {
                if &suspension != last_suspension {
                    // We remove previous suspension from the suspense.
                    suspense.resume(last_suspension.clone());
                }
            }
            state.suspension = Some(suspension.clone());

            suspense.suspend(suspension);
        }
    }

    fn render(&self, state: &mut ComponentState, new_root: Html) {
        // Currently not suspended, we remove any previous suspension and update
        // normally.
        if let Some(m) = state.suspension.take() {
            let comp_scope = state.inner.any_scope();

            let suspense_scope = comp_scope.find_parent_scope::<BaseSuspense>().unwrap();
            let suspense = suspense_scope.get_component().unwrap();

            suspense.resume(m);
        }

        match state.render_state {
            #[cfg(feature = "csr")]
            ComponentRenderState::Render {
                ref mut bundle,
                ref parent,
                ref root,
                ref next_sibling,
                ref node_ref,
                ..
            } => {
                let scope = state.inner.any_scope();

                let new_node_ref =
                    bundle.reconcile(root, &scope, parent, next_sibling.clone(), new_root);
                node_ref.link(new_node_ref);

                let first_render = !state.has_rendered;
                state.has_rendered = true;

                scheduler::push_component_rendered(
                    state.comp_id,
                    Box::new(RenderedRunner {
                        state: self.state.clone(),
                        first_render,
                    }),
                    first_render,
                );
            }

            #[cfg(feature = "hydration")]
            ComponentRenderState::Hydration {
                ref mut fragment,
                ref parent,
                ref node_ref,
                ref next_sibling,
                ref root,
            } => {
                // We schedule a "first" render to run immediately after hydration,
                // to fix NodeRefs (first_node and next_sibling).
                scheduler::push_component_priority_render(
                    state.comp_id,
                    Box::new(RenderRunner {
                        state: self.state.clone(),
                    }),
                );

                let scope = state.inner.any_scope();

                // This first node is not guaranteed to be correct here.
                // As it may be a comment node that is removed afterwards.
                // but we link it anyways.
                let (node, bundle) = Bundle::hydrate(root, &scope, parent, fragment, new_root);

                // We trim all text nodes before checking as it's likely these are whitespaces.
                fragment.trim_start_text_nodes(parent);

                assert!(fragment.is_empty(), "expected end of component, found node");

                node_ref.link(node);

                state.render_state = ComponentRenderState::Render {
                    root: root.clone(),
                    bundle,
                    parent: parent.clone(),
                    node_ref: node_ref.clone(),
                    next_sibling: next_sibling.clone(),
                };
            }

            #[cfg(feature = "ssr")]
            ComponentRenderState::Ssr { ref mut sender } => {
                if let Some(tx) = sender.take() {
                    tx.send(new_root).unwrap();
                }
            }
        };
    }
}

#[cfg(feature = "csr")]
mod feat_csr {
    use super::*;

    pub(crate) struct RenderedRunner {
        pub state: Shared<Option<ComponentState>>,
        pub first_render: bool,
    }

    impl Runnable for RenderedRunner {
        fn run(self: Box<Self>) {
            if let Some(state) = self.state.borrow_mut().as_mut() {
                #[cfg(debug_assertions)]
                super::super::log_event(state.comp_id, "rendered");

                if state.suspension.is_none() {
                    state.inner.rendered(self.first_render);
                }

                if let Some(m) = state.pending_props.take() {
                    scheduler::push_component_props_update(Box::new(PropsUpdateRunner {
                        props: m,
                        state: self.state.clone(),
                        next_sibling: None,
                    }));
                }
            }
        }
    }
}

#[cfg(feature = "csr")]
use feat_csr::*;

#[cfg(feature = "wasm_test")]
#[cfg(test)]
mod tests {
    extern crate self as yew;

    use std::cell::RefCell;
    use std::ops::Deref;
    use std::rc::Rc;

    use wasm_bindgen_test::{wasm_bindgen_test as test, wasm_bindgen_test_configure};

    use super::*;
    use crate::dom_bundle::BSubtree;
    use crate::html::*;
    use crate::{html, Properties};

    wasm_bindgen_test_configure!(run_in_browser);

    #[derive(Clone, Properties, Default, PartialEq)]
    struct ChildProps {
        lifecycle: Rc<RefCell<Vec<String>>>,
    }

    struct Child {}

    impl Component for Child {
        type Message = ();
        type Properties = ChildProps;

        fn create(_ctx: &Context<Self>) -> Self {
            Child {}
        }

        fn rendered(&mut self, ctx: &Context<Self>, _first_render: bool) {
            ctx.props()
                .lifecycle
                .borrow_mut()
                .push("child rendered".into());
        }

        fn update(&mut self, _ctx: &Context<Self>, _: Self::Message) -> bool {
            false
        }

        fn changed(&mut self, _ctx: &Context<Self>) -> bool {
            false
        }

        fn view(&self, _ctx: &Context<Self>) -> Html {
            html! {}
        }
    }

    #[derive(Clone, Properties, Default, PartialEq)]
    struct Props {
        lifecycle: Rc<RefCell<Vec<String>>>,
        #[allow(dead_code)]
        #[cfg(feature = "wasm_test")]
        create_message: Option<bool>,
        update_message: RefCell<Option<bool>>,
        view_message: RefCell<Option<bool>>,
        rendered_message: RefCell<Option<bool>>,
    }

    struct Comp {
        lifecycle: Rc<RefCell<Vec<String>>>,
    }

    impl Component for Comp {
        type Message = bool;
        type Properties = Props;

        fn create(ctx: &Context<Self>) -> Self {
            ctx.props().lifecycle.borrow_mut().push("create".into());
            #[cfg(feature = "wasm_test")]
            if let Some(msg) = ctx.props().create_message {
                ctx.link().send_message(msg);
            }
            Comp {
                lifecycle: Rc::clone(&ctx.props().lifecycle),
            }
        }

        fn rendered(&mut self, ctx: &Context<Self>, first_render: bool) {
            if let Some(msg) = ctx.props().rendered_message.borrow_mut().take() {
                ctx.link().send_message(msg);
            }
            ctx.props()
                .lifecycle
                .borrow_mut()
                .push(format!("rendered({})", first_render));
        }

        fn update(&mut self, ctx: &Context<Self>, msg: Self::Message) -> bool {
            if let Some(msg) = ctx.props().update_message.borrow_mut().take() {
                ctx.link().send_message(msg);
            }
            ctx.props()
                .lifecycle
                .borrow_mut()
                .push(format!("update({})", msg));
            msg
        }

        fn changed(&mut self, ctx: &Context<Self>) -> bool {
            self.lifecycle = Rc::clone(&ctx.props().lifecycle);
            self.lifecycle.borrow_mut().push("change".into());
            false
        }

        fn view(&self, ctx: &Context<Self>) -> Html {
            if let Some(msg) = ctx.props().view_message.borrow_mut().take() {
                ctx.link().send_message(msg);
            }
            self.lifecycle.borrow_mut().push("view".into());
            html! { <Child lifecycle={self.lifecycle.clone()} /> }
        }
    }

    impl Drop for Comp {
        fn drop(&mut self) {
            self.lifecycle.borrow_mut().push("drop".into());
        }
    }

    fn test_lifecycle(props: Props, expected: &[&str]) {
        let document = gloo_utils::document();
        let scope = Scope::<Comp>::new(None);
        let parent = document.create_element("div").unwrap();
        let root = BSubtree::create_root(&parent);

        let lifecycle = props.lifecycle.clone();

        lifecycle.borrow_mut().clear();
        scope.mount_in_place(
            root,
            parent,
            NodeRef::default(),
            NodeRef::default(),
            Rc::new(props),
        );
        crate::scheduler::start_now();

        assert_eq!(&lifecycle.borrow_mut().deref()[..], expected);
    }

    #[test]
    fn lifecycle_tests() {
        let lifecycle: Rc<RefCell<Vec<String>>> = Rc::default();

        test_lifecycle(
            Props {
                lifecycle: lifecycle.clone(),
                ..Props::default()
            },
            &["create", "view", "child rendered", "rendered(true)"],
        );

        test_lifecycle(
            Props {
                lifecycle: lifecycle.clone(),
                #[cfg(feature = "wasm_test")]
                create_message: Some(false),
                ..Props::default()
            },
            &[
                "create",
                "view",
                "child rendered",
                "rendered(true)",
                "update(false)",
            ],
        );

        test_lifecycle(
            Props {
                lifecycle: lifecycle.clone(),
                view_message: RefCell::new(Some(true)),
                ..Props::default()
            },
            &[
                "create",
                "view",
                "child rendered",
                "rendered(true)",
                "update(true)",
                "view",
                "rendered(false)",
            ],
        );

        test_lifecycle(
            Props {
                lifecycle: lifecycle.clone(),
                view_message: RefCell::new(Some(false)),
                ..Props::default()
            },
            &[
                "create",
                "view",
                "child rendered",
                "rendered(true)",
                "update(false)",
            ],
        );

        test_lifecycle(
            Props {
                lifecycle: lifecycle.clone(),
                rendered_message: RefCell::new(Some(false)),
                ..Props::default()
            },
            &[
                "create",
                "view",
                "child rendered",
                "rendered(true)",
                "update(false)",
            ],
        );

        test_lifecycle(
            Props {
                lifecycle: lifecycle.clone(),
                rendered_message: RefCell::new(Some(true)),
                ..Props::default()
            },
            &[
                "create",
                "view",
                "child rendered",
                "rendered(true)",
                "update(true)",
                "view",
                "rendered(false)",
            ],
        );

        // This also tests render deduplication after the first render
        test_lifecycle(
            Props {
                lifecycle,
                #[cfg(feature = "wasm_test")]
                create_message: Some(true),
                update_message: RefCell::new(Some(true)),
                ..Props::default()
            },
            &[
                "create",
                "view",
                "child rendered",
                "rendered(true)",
                "update(true)",
                "update(true)",
                "view",
                "rendered(false)",
            ],
        );
    }
}