diff options
Diffstat (limited to 'plumbing/format/commitgraph')
| -rw-r--r-- | plumbing/format/commitgraph/encoder.go | 2 | ||||
| -rw-r--r-- | plumbing/format/commitgraph/file.go | 81 |
2 files changed, 51 insertions, 32 deletions
diff --git a/plumbing/format/commitgraph/encoder.go b/plumbing/format/commitgraph/encoder.go index a4c5ad3..b4a6978 100644 --- a/plumbing/format/commitgraph/encoder.go +++ b/plumbing/format/commitgraph/encoder.go @@ -107,7 +107,7 @@ func (e *Encoder) encodeChunkHeaders(chunkSignatures [][]byte, chunkSizes []uint }
offset += chunkSizes[i]
}
- if _, err = e.Write([]byte{0, 0, 0, 0}); err == nil {
+ if _, err = e.Write(lastSignature); err == nil {
err = binary.WriteUint64(e, offset)
}
return
diff --git a/plumbing/format/commitgraph/file.go b/plumbing/format/commitgraph/file.go index fd173ff..dce6243 100644 --- a/plumbing/format/commitgraph/file.go +++ b/plumbing/format/commitgraph/file.go @@ -28,6 +28,7 @@ var ( oidLookupSignature = []byte{'O', 'I', 'D', 'L'}
commitDataSignature = []byte{'C', 'D', 'A', 'T'}
largeEdgeListSignature = []byte{'E', 'D', 'G', 'E'}
+ lastSignature = []byte{0, 0, 0, 0}
parentNone = uint32(0x70000000)
parentOctopusUsed = uint32(0x80000000)
@@ -38,6 +39,7 @@ var ( type fileIndex struct {
reader io.ReaderAt
fanout [256]int
+ oidFanoutOffset int64
oidLookupOffset int64
commitDataOffset int64
largeEdgeListOffset int64
@@ -46,74 +48,91 @@ type fileIndex struct { // OpenFileIndex opens a serialized commit graph file in the format described at
// https://github.com/git/git/blob/master/Documentation/technical/commit-graph-format.txt
func OpenFileIndex(reader io.ReaderAt) (Index, error) {
+ fi := &fileIndex{reader: reader}
+
+ if err := fi.verifyFileHeader(); err != nil {
+ return nil, err
+ }
+ if err := fi.readChunkHeaders(); err != nil {
+ return nil, err
+ }
+ if err := fi.readFanout(); err != nil {
+ return nil, err
+ }
+
+ return fi, nil
+}
+
+func (fi *fileIndex) verifyFileHeader() error {
// Verify file signature
var signature = make([]byte, 4)
- if _, err := reader.ReadAt(signature, 0); err != nil {
- return nil, err
+ if _, err := fi.reader.ReadAt(signature, 0); err != nil {
+ return err
}
if !bytes.Equal(signature, commitFileSignature) {
- return nil, ErrMalformedCommitGraphFile
+ return ErrMalformedCommitGraphFile
}
// Read and verify the file header
var header = make([]byte, 4)
- if _, err := reader.ReadAt(header, 4); err != nil {
- return nil, err
+ if _, err := fi.reader.ReadAt(header, 4); err != nil {
+ return err
}
if header[0] != 1 {
- return nil, ErrUnsupportedVersion
+ return ErrUnsupportedVersion
}
if header[1] != 1 {
- return nil, ErrUnsupportedHash
+ return ErrUnsupportedHash
}
- // Read chunk headers
+ return nil
+}
+
+func (fi *fileIndex) readChunkHeaders() error {
var chunkID = make([]byte, 4)
- var oidFanoutOffset int64
- var oidLookupOffset int64
- var commitDataOffset int64
- var largeEdgeListOffset int64
- chunkCount := int(header[2])
- for i := 0; i < chunkCount; i++ {
- chunkHeader := io.NewSectionReader(reader, 8+(int64(i)*12), 12)
+ for i := 0; ; i++ {
+ chunkHeader := io.NewSectionReader(fi.reader, 8+(int64(i)*12), 12)
if _, err := io.ReadAtLeast(chunkHeader, chunkID, 4); err != nil {
- return nil, err
+ return err
}
chunkOffset, err := binary.ReadUint64(chunkHeader)
if err != nil {
- return nil, err
+ return err
}
if bytes.Equal(chunkID, oidFanoutSignature) {
- oidFanoutOffset = int64(chunkOffset)
+ fi.oidFanoutOffset = int64(chunkOffset)
} else if bytes.Equal(chunkID, oidLookupSignature) {
- oidLookupOffset = int64(chunkOffset)
+ fi.oidLookupOffset = int64(chunkOffset)
} else if bytes.Equal(chunkID, commitDataSignature) {
- commitDataOffset = int64(chunkOffset)
+ fi.commitDataOffset = int64(chunkOffset)
} else if bytes.Equal(chunkID, largeEdgeListSignature) {
- largeEdgeListOffset = int64(chunkOffset)
+ fi.largeEdgeListOffset = int64(chunkOffset)
+ } else if bytes.Equal(chunkID, lastSignature) {
+ break
}
}
- if oidFanoutOffset <= 0 || oidLookupOffset <= 0 || commitDataOffset <= 0 {
- return nil, ErrMalformedCommitGraphFile
+ if fi.oidFanoutOffset <= 0 || fi.oidLookupOffset <= 0 || fi.commitDataOffset <= 0 {
+ return ErrMalformedCommitGraphFile
}
- // Read fanout table and calculate the file offsets into the lookup table
- fanoutReader := io.NewSectionReader(reader, oidFanoutOffset, 256*4)
- var fanout [256]int
+ return nil
+}
+
+func (fi *fileIndex) readFanout() error {
+ fanoutReader := io.NewSectionReader(fi.reader, fi.oidFanoutOffset, 256*4)
for i := 0; i < 256; i++ {
fanoutValue, err := binary.ReadUint32(fanoutReader)
if err != nil {
- return nil, err
+ return err
}
if fanoutValue > 0x7fffffff {
- return nil, ErrMalformedCommitGraphFile
+ return ErrMalformedCommitGraphFile
}
- fanout[i] = int(fanoutValue)
+ fi.fanout[i] = int(fanoutValue)
}
-
- return &fileIndex{reader, fanout, oidLookupOffset, commitDataOffset, largeEdgeListOffset}, nil
+ return nil
}
func (fi *fileIndex) GetIndexByHash(h plumbing.Hash) (int, error) {
|