feat: refs support pseudo refs

Author: orthros

gix-ref/src/store/file/loose/iter.rs

@@ -11,20 +11,31 @@ pub(in crate::store_impl::file) struct SortedLoosePaths {
     pub(crate) base: PathBuf,
     /// An prefix like `refs/heads/foo/` or `refs/heads/prefix` that a returned reference must match against..
     prefix: Option<BString>,
+    /// A suffix like `HEAD` that a returned reference must match against..
+    suffix: Option<BString>,
     file_walk: Option<DirEntryIter>,
 }
 
 impl SortedLoosePaths {
-    pub fn at(path: &Path, base: PathBuf, prefix: Option<BString>, precompose_unicode: bool) -> Self {
+    pub fn at(
+        path: &Path,
+        base: PathBuf,
+        prefix: Option<BString>,
+        suffix: Option<BString>,
+        root_only: bool,
+        precompose_unicode: bool,
+    ) -> Self {
+        let depth = if root_only { 1 } else { usize::MAX };
         SortedLoosePaths {
             base,
             prefix,
+            suffix,
             file_walk: path.is_dir().then(|| {
                 // serial iteration as we expect most refs in packed-refs anyway.
                 gix_features::fs::walkdir_sorted_new(
                     path,
                     gix_features::fs::walkdir::Parallelism::Serial,
-                    usize::MAX,
+                    depth,
                     precompose_unicode,
                 )
                 .into_iter()
@@ -57,6 +68,11 @@ impl Iterator for SortedLoosePaths {
                             continue;
                         }
                     }
+                    if let Some(suffix) = &self.suffix {
+                        if !full_name.ends_with(suffix) {
+                            continue;
+                        }
+                    }
                     if gix_validate::reference::name_partial(full_name.as_bstr()).is_ok() {
                         let name = FullName(full_name);
                         return Some(Ok((full_path, name)));

gix-ref/src/store/file/overlay_iter.rs

@@ -10,7 +10,7 @@ use gix_object::bstr::ByteSlice;
 use gix_path::RelativePath;
 
 use crate::{
-    file::{loose, loose::iter::SortedLoosePaths},
+    file::loose::{self, iter::SortedLoosePaths},
     store_impl::{file, packed},
     BStr, FullName, Namespace, Reference,
 };
@@ -85,36 +85,48 @@ impl<'p> LooseThenPacked<'p, '_> {
     }
 
     fn convert_loose(&mut self, res: std::io::Result<(PathBuf, FullName)>) -> Result<Reference, Error> {
-        let (refpath, name) = res.map_err(Error::Traversal)?;
-        std::fs::File::open(&refpath)
-            .and_then(|mut f| {
-                self.buf.clear();
-                f.read_to_end(&mut self.buf)
-            })
-            .map_err(|err| Error::ReadFileContents {
-                source: err,
-                path: refpath.to_owned(),
-            })?;
-        loose::Reference::try_from_path(name, &self.buf)
-            .map_err(|err| {
-                let relative_path = refpath
-                    .strip_prefix(self.git_dir)
-                    .ok()
-                    .or_else(|| {
-                        self.common_dir
-                            .and_then(|common_dir| refpath.strip_prefix(common_dir).ok())
-                    })
-                    .expect("one of our bases contains the path");
-                Error::ReferenceCreation {
-                    source: err,
-                    relative_path: relative_path.into(),
-                }
-            })
-            .map(Into::into)
-            .map(|r| self.strip_namespace(r))
+        convert_loose(&mut self.buf, self.git_dir, self.common_dir, self.namespace, res)
     }
 }
 
+pub(crate) fn convert_loose(
+    buf: &mut Vec<u8>,
+    git_dir: &Path,
+    common_dir: Option<&Path>,
+    namespace: Option<&Namespace>,
+    res: std::io::Result<(PathBuf, FullName)>,
+) -> Result<Reference, Error> {
+    let (refpath, name) = res.map_err(Error::Traversal)?;
+    std::fs::File::open(&refpath)
+        .and_then(|mut f| {
+            buf.clear();
+            f.read_to_end(buf)
+        })
+        .map_err(|err| Error::ReadFileContents {
+            source: err,
+            path: refpath.to_owned(),
+        })?;
+    loose::Reference::try_from_path(name, buf)
+        .map_err(|err| {
+            let relative_path = refpath
+                .strip_prefix(git_dir)
+                .ok()
+                .or_else(|| common_dir.and_then(|common_dir| refpath.strip_prefix(common_dir).ok()))
+                .expect("one of our bases contains the path");
+            Error::ReferenceCreation {
+                source: err,
+                relative_path: relative_path.into(),
+            }
+        })
+        .map(Into::into)
+        .map(|mut r: Reference| {
+            if let Some(namespace) = namespace {
+                r.strip_namespace(namespace);
+            }
+            r
+        })
+}
+
 impl Iterator for LooseThenPacked<'_, '_> {
     type Item = Result<Reference, Error>;
 
@@ -210,6 +222,11 @@ impl Platform<'_> {
         self.store
             .iter_prefixed_packed(prefix, self.packed.as_ref().map(|b| &***b))
     }
+
+    /// Return an iterator over the pseudo references
+    pub fn psuedo_refs(&self) -> std::io::Result<LooseThenPacked<'_, '_>> {
+        self.store.iter_pseudo_refs()
+    }
 }
 
 impl file::Store {
@@ -254,6 +271,10 @@ pub(crate) enum IterInfo<'a> {
         /// If `true`, we will convert decomposed into precomposed unicode.
         precompose_unicode: bool,
     },
+    PseudoRefs {
+        base: &'a Path,
+        precompose_unicode: bool,
+    },
 }
 
 impl<'a> IterInfo<'a> {
@@ -263,6 +284,7 @@ impl<'a> IterInfo<'a> {
             IterInfo::PrefixAndBase { prefix, .. } => Some(gix_path::into_bstr(*prefix)),
             IterInfo::BaseAndIterRoot { prefix, .. } => Some(gix_path::into_bstr(prefix.clone())),
             IterInfo::ComputedIterationRoot { prefix, .. } => Some(prefix.clone()),
+            IterInfo::PseudoRefs { .. } => None,
         }
     }
 
@@ -271,24 +293,35 @@ impl<'a> IterInfo<'a> {
             IterInfo::Base {
                 base,
                 precompose_unicode,
-            } => SortedLoosePaths::at(&base.join("refs"), base.into(), None, precompose_unicode),
+            } => SortedLoosePaths::at(&base.join("refs"), base.into(), None, None, false, precompose_unicode),
             IterInfo::BaseAndIterRoot {
                 base,
                 iter_root,
                 prefix: _,
                 precompose_unicode,
-            } => SortedLoosePaths::at(&iter_root, base.into(), None, precompose_unicode),
+            } => SortedLoosePaths::at(&iter_root, base.into(), None, None, false, precompose_unicode),
             IterInfo::PrefixAndBase {
                 base,
                 prefix,
                 precompose_unicode,
-            } => SortedLoosePaths::at(&base.join(prefix), base.into(), None, precompose_unicode),
+            } => SortedLoosePaths::at(&base.join(prefix), base.into(), None, None, false, precompose_unicode),
             IterInfo::ComputedIterationRoot {
                 iter_root,
                 base,
                 prefix,
                 precompose_unicode,
-            } => SortedLoosePaths::at(&iter_root, base.into(), Some(prefix.into_owned()), precompose_unicode),
+            } => SortedLoosePaths::at(
+                &iter_root,
+                base.into(),
+                Some(prefix.into_owned()),
+                None,
+                false,
+                precompose_unicode,
+            ),
+            IterInfo::PseudoRefs {
+                base,
+                precompose_unicode,
+            } => SortedLoosePaths::at(base, base.into(), None, Some("HEAD".into()), true, precompose_unicode),
         }
         .peekable()
     }
@@ -354,6 +387,20 @@ impl file::Store {
         }
     }
 
+    /// Return an iterator over all pseudo references, loose or `packed`, sorted by their name.
+    ///
+    /// Errors are returned similarly to what would happen when loose and packed refs where iterated by themselves.
+    pub fn iter_pseudo_refs<'p>(&'_ self) -> std::io::Result<LooseThenPacked<'p, '_>> {
+        self.iter_from_info(
+            IterInfo::PseudoRefs {
+                base: self.git_dir(),
+                precompose_unicode: self.precompose_unicode,
+            },
+            None,
+            None,
+        )
+    }
+
     /// As [`iter(…)`](file::Store::iter()), but filters by `prefix`, i.e. `refs/heads/` or
     /// `refs/heads/feature-`.
     /// Note that if a prefix isn't using a trailing `/`, like in `refs/heads/foo`, it will effectively

gix-ref/tests/fixtures/generated-archives/make_pref_repository.tar

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+set -eu -o pipefail
+
+git init -q
+
+git checkout -q -b main
+git commit -q --allow-empty -m c1
+git branch dt1
+git branch d1
+git branch A
+
+mkdir -p .git/refs/remotes/origin
+mkdir -p .git/refs/prefix/feature/sub/dir
+
+cp .git/refs/heads/main .git/refs/remotes/origin/
+cp .git/refs/heads/main .git/refs/d1
+cp .git/refs/heads/main .git/refs/prefix/feature-suffix
+cp .git/refs/heads/main .git/refs/prefix/feature/sub/dir/algo
+
+echo "ref: refs/remotes/origin/main" > .git/refs/remotes/origin/HEAD
+echo "notahexsha" > .git/refs/broken
+
+git rev-parse HEAD > .git/JIRI_HEAD
+touch .git/SOME_ALL_CAPS_FILE
+touch .git/refs/SHOULD_BE_EXCLUDED_HEAD
+
+cat <<EOF >> .git/FETCH_HEAD
+9064ea31fae4dc59a56bdd3a06c0ddc990ee689e		branch 'main' of https://github.com/Byron/gitoxide
+1b8d9e6a408e480ae1912e919c37a26e5c46639d	not-for-merge	branch 'faster-discovery' of https://github.com/Byron/gitoxide
+43f695a9607f1f85f859f2ef944b785b5b6dd238	not-for-merge	branch 'fix-823' of https://github.com/Byron/gitoxide
+96267708958ead2646aae8766a50fa060739003c	not-for-merge	branch 'fix-bare-with-index' of https://github.com/Byron/gitoxide
+1397e19375bb98522f951b8a452b08c1b35ffbac	not-for-merge	branch 'gix-archive' of https://github.com/Byron/gitoxide
+db71ec8b7c7f2730c47dde3bb662ab56ae89ae7d	not-for-merge	branch 'index-from-files' of https://github.com/Byron/gitoxide
+9f0c71917e57653d2e7121eae65d9385a188a8df	not-for-merge	branch 'moonwalk' of https://github.com/Byron/gitoxide
+44d2b67de5639d4ea3d08ab030ecfe4bdfc8cbfb	not-for-merge	branch 'release-gix' of https://github.com/Byron/gitoxide
+37c3d073b15dafcb52b2040e4b92a413c69a726d	not-for-merge	branch 'smart-release-without-git2' of https://github.com/Byron/gitoxide
+af3608ad397784795c3758a1ac99ec6a367de9be	not-for-merge	branch 'walk-with-commitgraph' of https://github.com/Byron/gitoxide
+EOF
+
+git tag t1
+git tag -m "tag object" dt1

gix-ref/tests/fixtures/make_pref_repository.sh

@@ -39,6 +39,7 @@ mod partialname {
 }
 mod namespace;
 mod packed;
+mod pseudo_refs;
 mod reference;
 mod store;
 mod transaction;

gix-ref/tests/refs/main.rs

@@ -0,0 +1,21 @@
+use crate::file::store_at;
+
+#[test]
+fn pseudo_refs_iterate_valid_pseudorefs() -> crate::Result {
+    let store = store_at("make_pref_repository.sh")?;
+
+    let prefs = store
+        .iter_pseudo_refs()?
+        .map(Result::unwrap)
+        .map(|r: gix_ref::Reference| r.name)
+        .collect::<Vec<_>>();
+
+    let expected_prefs = vec!["FETCH_HEAD", "HEAD", "JIRI_HEAD"];
+
+    assert_eq!(
+        prefs.iter().map(gix_ref::FullName::as_bstr).collect::<Vec<_>>(),
+        expected_prefs
+    );
+
+    Ok(())
+}