refactor

gix/src/repository/config/branch.rs

@@ -0,0 +1,213 @@
+use std::{borrow::Cow, collections::BTreeSet, convert::TryInto};
+
+use gix_ref::{FullName, FullNameRef};
+
+use crate::bstr::BStr;
+use crate::config::cache::util::ApplyLeniencyDefault;
+use crate::config::tree::{Branch, Push, Section};
+use crate::repository::{branch_remote_ref_name, branch_remote_tracking_ref_name};
+use crate::{push, remote};
+
+/// Query configuration related to branches.
+impl crate::Repository {
+    /// Return a set of unique short branch names for which custom configuration exists in the configuration,
+    /// if we deem them [trustworthy][crate::open::Options::filter_config_section()].
+    ///
+    /// ### Note
+    ///
+    /// Branch names that have illformed UTF-8 will silently be skipped.
+    pub fn branch_names(&self) -> BTreeSet<&str> {
+        self.subsection_str_names_of("branch")
+    }
+
+    /// Returns the validated reference on the remote associated with the given `name`,
+    /// which will be used when *merging*.
+    /// The returned value corresponds to the `branch.<short_branch_name>.merge` configuration key.
+    ///
+    /// Returns `None` if there is no value at the given key, or if no remote or remote ref is configured.
+    /// May return an error if the reference name to be returned is invalid.
+    ///
+    /// ### Note
+    ///
+    /// This name refers to what Git calls upstream branch (as opposed to upstream *tracking* branch).
+    /// The value is also fast to retrieve compared to its tracking branch.
+    /// Also note that a [remote::Direction] isn't used here as Git only supports (and requires) configuring
+    /// the remote to fetch from, not the one to push to.
+    ///
+    /// See also [`Reference::remote_ref_name()`](crate::Reference::remote_ref_name()).
+    #[doc(alias = "branch_upstream_name", alias = "git2")]
+    pub fn branch_remote_ref_name(
+        &self,
+        name: &FullNameRef,
+        direction: remote::Direction,
+    ) -> Option<Result<Cow<'_, FullNameRef>, branch_remote_ref_name::Error>> {
+        match direction {
+            remote::Direction::Fetch => {
+                let short_name = name.shorten();
+                self.config
+                    .resolved
+                    .string("branch", Some(short_name), Branch::MERGE.name)
+                    .map(|name| crate::config::tree::branch::Merge::try_into_fullrefname(name).map_err(Into::into))
+            }
+            remote::Direction::Push => {
+                let remote = match self.branch_remote(name.shorten(), direction)? {
+                    Ok(r) => r,
+                    Err(err) => return Some(Err(err.into())),
+                };
+                if remote.push_specs.is_empty() {
+                    let push_default = match self
+                        .config
+                        .resolved
+                        .string(Push.name(), None, Push::DEFAULT.name)
+                        .map_or(Ok(Default::default()), |v| {
+                            Push::DEFAULT
+                                .try_into_default(v)
+                                .with_lenient_default(self.config.lenient_config)
+                        }) {
+                        Ok(v) => v,
+                        Err(err) => return Some(Err(err.into())),
+                    };
+                    match push_default {
+                        push::Default::Nothing => None,
+                        push::Default::Current | push::Default::Matching => Some(Ok(Cow::Owned(name.to_owned()))),
+                        push::Default::Upstream => self.branch_remote_ref_name(name, remote::Direction::Fetch),
+                        push::Default::Simple => match self.branch_remote_ref_name(name, remote::Direction::Fetch)? {
+                            Ok(fetch_ref) if fetch_ref.as_ref() == name => Some(Ok(fetch_ref)),
+                            Err(err) => Some(Err(err)),
+                            Ok(_different_fetch_ref) => None,
+                        },
+                    }
+                } else {
+                    matching_remote(name, remote.push_specs.iter(), self.object_hash())
+                        .map(|res| res.map_err(Into::into))
+                }
+            }
+        }
+    }
+
+    /// Return the validated name of the reference that tracks the corresponding reference of `name` on the remote for
+    /// `direction`. Note that a branch with that name might not actually exist.
+    ///
+    /// * with `remote` being [remote::Direction::Fetch], we return the tracking branch that is on the destination
+    ///   side of a `src:dest` refspec. For instance, with `name` being `main` and the default refspec
+    ///   `refs/heads/*:refs/remotes/origin/*`, `refs/heads/main` would match and produce `refs/remotes/origin/main`.
+    /// * with `remote` being [remote::Direction::Push], we return the tracking branch that corresponds to the remote
+    ///   branch that we would push to. For instance, with `name` being `main` and no setup at all, we
+    ///   would push to `refs/heads/main` on the remote. And that one would be fetched matching the
+    ///   `refs/heads/*:refs/remotes/origin/*` fetch refspec, hence `refs/remotes/origin/main` is returned.
+    ///   Note that `push` refspecs can be used to map `main` to `other` (using a push refspec `refs/heads/main:refs/heads/other`),
+    ///   which would then lead to `refs/remotes/origin/other` to be returned instead.
+    ///
+    /// Note that if there is an ambiguity, that is if `name` maps to multiple tracking branches, the first matching mapping
+    /// is returned, according to the order in which the fetch or push refspecs occour in the configuration file.
+    ///
+    /// See also [`Reference::remote_tracking_ref_name()`](crate::Reference::remote_tracking_ref_name()).
+    #[doc(alias = "branch_upstream_name", alias = "git2")]
+    pub fn branch_remote_tracking_ref_name(
+        &self,
+        name: &FullNameRef,
+        direction: remote::Direction,
+    ) -> Option<Result<Cow<'_, FullNameRef>, branch_remote_tracking_ref_name::Error>> {
+        let remote_ref = match self.branch_remote_ref_name(name, direction)? {
+            Ok(r) => r,
+            Err(err) => return Some(Err(err.into())),
+        };
+        let remote = match self.branch_remote(name.shorten(), direction)? {
+            Ok(r) => r,
+            Err(err) => return Some(Err(err.into())),
+        };
+
+        if remote.fetch_specs.is_empty() {
+            return None;
+        }
+        matching_remote(remote_ref.as_ref(), remote.fetch_specs.iter(), self.object_hash())
+            .map(|res| res.map_err(Into::into))
+    }
+
+    /// Returns the unvalidated name of the remote associated with the given `short_branch_name`,
+    /// typically `main` instead of `refs/heads/main`.
+    /// In some cases, the returned name will be an URL.
+    /// Returns `None` if the remote was not found or if the name contained illformed UTF-8.
+    ///
+    /// * if `direction` is [remote::Direction::Fetch], we will query the `branch.<short_name>.remote` configuration.
+    /// * if `direction` is [remote::Direction::Push], the push remote will be queried by means of `branch.<short_name>.pushRemote`
+    ///   or `remote.pushDefault` as fallback.
+    ///
+    /// See also [`Reference::remote_name()`](crate::Reference::remote_name()) for a more typesafe version
+    /// to be used when a `Reference` is available.
+    ///
+    /// `short_branch_name` can typically be obtained by [shortening a full branch name](FullNameRef::shorten()).
+    #[doc(alias = "branch_upstream_remote", alias = "git2")]
+    pub fn branch_remote_name<'a>(
+        &self,
+        short_branch_name: impl Into<&'a BStr>,
+        direction: remote::Direction,
+    ) -> Option<remote::Name<'_>> {
+        let name = short_branch_name.into();
+        let config = &self.config.resolved;
+        (direction == remote::Direction::Push)
+            .then(|| {
+                config
+                    .string("branch", Some(name), Branch::PUSH_REMOTE.name)
+                    .or_else(|| config.string("remote", None, crate::config::tree::Remote::PUSH_DEFAULT.name))
+            })
+            .flatten()
+            .or_else(|| config.string("branch", Some(name), Branch::REMOTE.name))
+            .and_then(|name| name.try_into().ok())
+    }
+
+    /// Like [`branch_remote_name(…)`](Self::branch_remote_name()), but returns a [Remote](crate::Remote).
+    /// `short_branch_name` is the name to use for looking up `branch.<short_branch_name>.*` values in the
+    /// configuration.
+    ///
+    /// See also [`Reference::remote()`](crate::Reference::remote()).
+    pub fn branch_remote<'a>(
+        &self,
+        short_branch_name: impl Into<&'a BStr>,
+        direction: remote::Direction,
+    ) -> Option<Result<crate::Remote<'_>, remote::find::existing::Error>> {
+        let name = self.branch_remote_name(short_branch_name, direction)?;
+        self.try_find_remote(name.as_bstr())
+            .map(|res| res.map_err(Into::into))
+            .or_else(|| match name {
+                remote::Name::Url(url) => gix_url::parse(url.as_ref())
+                    .map_err(Into::into)
+                    .and_then(|url| {
+                        self.remote_at(url)
+                            .map_err(|err| remote::find::existing::Error::Find(remote::find::Error::Init(err)))
+                    })
+                    .into(),
+                remote::Name::Symbol(_) => None,
+            })
+    }
+}
+
+fn matching_remote<'a>(
+    lhs: &FullNameRef,
+    specs: impl IntoIterator<Item = &'a gix_refspec::RefSpec>,
+    object_hash: gix_hash::Kind,
+) -> Option<Result<Cow<'static, FullNameRef>, gix_validate::reference::name::Error>> {
+    let search = gix_refspec::MatchGroup {
+        specs: specs
+            .into_iter()
+            .map(gix_refspec::RefSpec::to_ref)
+            .filter(|spec| spec.source().is_some() && spec.destination().is_some())
+            .collect(),
+    };
+    let null_id = object_hash.null();
+    let out = search.match_remotes(
+        Some(gix_refspec::match_group::Item {
+            full_ref_name: lhs.as_bstr(),
+            target: &null_id,
+            object: None,
+        })
+        .into_iter(),
+    );
+    out.mappings.into_iter().next().and_then(|m| {
+        m.rhs.map(|name| {
+            FullName::try_from(name.into_owned())
+                .map(Cow::Owned)
+                .map_err(Into::into)
+        })
+    })
+}