Merge pull request #1025 from mcuadros/eoie
plumbing: format/index: support for EOIE extension
diff --git a/plumbing/format/index/decoder.go b/plumbing/format/index/decoder.go
index df25530..ac57d08 100644
--- a/plumbing/format/index/decoder.go
+++ b/plumbing/format/index/decoder.go
@@ -261,6 +261,17 @@
if err := d.Decode(idx.ResolveUndo); err != nil {
return err
}
+ case bytes.Equal(header, endOfIndexEntryExtSignature):
+ r, err := d.getExtensionReader()
+ if err != nil {
+ return err
+ }
+
+ idx.EndOfIndexEntry = &EndOfIndexEntry{}
+ d := &endOfIndexEntryDecoder{r}
+ if err := d.Decode(idx.EndOfIndexEntry); err != nil {
+ return err
+ }
default:
return errUnknownExtension
}
@@ -449,3 +460,17 @@
return nil
}
+
+type endOfIndexEntryDecoder struct {
+ r io.Reader
+}
+
+func (d *endOfIndexEntryDecoder) Decode(e *EndOfIndexEntry) error {
+ var err error
+ e.Offset, err = binary.ReadUint32(d.r)
+ if err != nil {
+ return err
+ }
+
+ return binary.Read(d.r, &e.Hash)
+}
diff --git a/plumbing/format/index/decoder_test.go b/plumbing/format/index/decoder_test.go
index b612ebb..7468ad0 100644
--- a/plumbing/format/index/decoder_test.go
+++ b/plumbing/format/index/decoder_test.go
@@ -202,3 +202,19 @@
c.Assert(idx.Entries[6].IntentToAdd, Equals, true)
c.Assert(idx.Entries[6].SkipWorktree, Equals, false)
}
+
+func (s *IndexSuite) TestDecodeEndOfIndexEntry(c *C) {
+ f, err := fixtures.Basic().ByTag("end-of-index-entry").One().DotGit().Open("index")
+ c.Assert(err, IsNil)
+ defer func() { c.Assert(f.Close(), IsNil) }()
+
+ idx := &Index{}
+ d := NewDecoder(f)
+ err = d.Decode(idx)
+ c.Assert(err, IsNil)
+
+ c.Assert(idx.Version, Equals, uint32(2))
+ c.Assert(idx.EndOfIndexEntry, NotNil)
+ c.Assert(idx.EndOfIndexEntry.Offset, Equals, uint32(716))
+ c.Assert(idx.EndOfIndexEntry.Hash.String(), Equals, "922e89d9ffd7cefce93a211615b2053c0f42bd78")
+}
diff --git a/plumbing/format/index/doc.go b/plumbing/format/index/doc.go
index d1e7b33..f2b3d76 100644
--- a/plumbing/format/index/doc.go
+++ b/plumbing/format/index/doc.go
@@ -297,5 +297,64 @@
// in the previous ewah bitmap.
//
// - One NUL.
-// Source https://www.kernel.org/pub/software/scm/git/docs/technical/index-format.txt
+//
+// == File System Monitor cache
+//
+// The file system monitor cache tracks files for which the core.fsmonitor
+// hook has told us about changes. The signature for this extension is
+// { 'F', 'S', 'M', 'N' }.
+//
+// The extension starts with
+//
+// - 32-bit version number: the current supported version is 1.
+//
+// - 64-bit time: the extension data reflects all changes through the given
+// time which is stored as the nanoseconds elapsed since midnight,
+// January 1, 1970.
+//
+// - 32-bit bitmap size: the size of the CE_FSMONITOR_VALID bitmap.
+//
+// - An ewah bitmap, the n-th bit indicates whether the n-th index entry
+// is not CE_FSMONITOR_VALID.
+//
+// == End of Index Entry
+//
+// The End of Index Entry (EOIE) is used to locate the end of the variable
+// length index entries and the begining of the extensions. Code can take
+// advantage of this to quickly locate the index extensions without having
+// to parse through all of the index entries.
+//
+// Because it must be able to be loaded before the variable length cache
+// entries and other index extensions, this extension must be written last.
+// The signature for this extension is { 'E', 'O', 'I', 'E' }.
+//
+// The extension consists of:
+//
+// - 32-bit offset to the end of the index entries
+//
+// - 160-bit SHA-1 over the extension types and their sizes (but not
+// their contents). E.g. if we have "TREE" extension that is N-bytes
+// long, "REUC" extension that is M-bytes long, followed by "EOIE",
+// then the hash would be:
+//
+// SHA-1("TREE" + <binary representation of N> +
+// "REUC" + <binary representation of M>)
+//
+// == Index Entry Offset Table
+//
+// The Index Entry Offset Table (IEOT) is used to help address the CPU
+// cost of loading the index by enabling multi-threading the process of
+// converting cache entries from the on-disk format to the in-memory format.
+// The signature for this extension is { 'I', 'E', 'O', 'T' }.
+//
+// The extension consists of:
+//
+// - 32-bit version (currently 1)
+//
+// - A number of index offset entries each consisting of:
+//
+// - 32-bit offset from the begining of the file to the first cache entry
+// in this block of entries.
+//
+// - 32-bit count of cache entries in this blockpackage index
package index
diff --git a/plumbing/format/index/index.go b/plumbing/format/index/index.go
index fc7b8cd..6c4b7ca 100644
--- a/plumbing/format/index/index.go
+++ b/plumbing/format/index/index.go
@@ -18,9 +18,10 @@
// ErrEntryNotFound is returned by Index.Entry, if an entry is not found.
ErrEntryNotFound = errors.New("entry not found")
- indexSignature = []byte{'D', 'I', 'R', 'C'}
- treeExtSignature = []byte{'T', 'R', 'E', 'E'}
- resolveUndoExtSignature = []byte{'R', 'E', 'U', 'C'}
+ indexSignature = []byte{'D', 'I', 'R', 'C'}
+ treeExtSignature = []byte{'T', 'R', 'E', 'E'}
+ resolveUndoExtSignature = []byte{'R', 'E', 'U', 'C'}
+ endOfIndexEntryExtSignature = []byte{'E', 'O', 'I', 'E'}
)
// Stage during merge
@@ -50,6 +51,8 @@
Cache *Tree
// ResolveUndo represents the 'Resolve undo' extension
ResolveUndo *ResolveUndo
+ // EndOfIndexEntry represents the 'End of Index Entry' extension
+ EndOfIndexEntry *EndOfIndexEntry
}
// Add creates a new Entry and returns it. The caller should first check that
@@ -193,3 +196,18 @@
Path string
Stages map[Stage]plumbing.Hash
}
+
+// EndOfIndexEntry is the End of Index Entry (EOIE) is used to locate the end of
+// the variable length index entries and the begining of the extensions. Code
+// can take advantage of this to quickly locate the index extensions without
+// having to parse through all of the index entries.
+//
+// Because it must be able to be loaded before the variable length cache
+// entries and other index extensions, this extension must be written last.
+type EndOfIndexEntry struct {
+ // Offset to the end of the index entries
+ Offset uint32
+ // Hash is a SHA-1 over the extension types and their sizes (but not
+ // their contents).
+ Hash plumbing.Hash
+}
