From 9c9c8c331b6bdb8fd5710c433e0dfd42f756d119 Mon Sep 17 00:00:00 2001 From: Andrew Thornton Date: Sat, 30 Sep 2023 09:09:10 +0100 Subject: plumbing: commitgraph, allow SHA256 commit-graphs Since the build-tag sha256 was introduced the commit graph code should be switched to use hash.Size and only use a graph if it has the correct hash version for the version of go-git that is built. Signed-off-by: Andrew Thornton --- plumbing/format/commitgraph/encoder.go | 9 +++++++-- plumbing/format/commitgraph/file.go | 35 +++++++++++++++++++++++----------- 2 files changed, 31 insertions(+), 13 deletions(-) diff --git a/plumbing/format/commitgraph/encoder.go b/plumbing/format/commitgraph/encoder.go index f61025b..674f52e 100644 --- a/plumbing/format/commitgraph/encoder.go +++ b/plumbing/format/commitgraph/encoder.go @@ -1,6 +1,7 @@ package commitgraph import ( + "crypto" "io" "github.com/go-git/go-git/v5/plumbing" @@ -30,7 +31,7 @@ func (e *Encoder) Encode(idx Index) error { hashToIndex, fanout, extraEdgesCount := e.prepare(idx, hashes) chunkSignatures := [][]byte{oidFanoutSignature, oidLookupSignature, commitDataSignature} - chunkSizes := []uint64{4 * 256, uint64(len(hashes)) * hash.Size, uint64(len(hashes)) * 36} + chunkSizes := []uint64{4 * 256, uint64(len(hashes)) * hash.Size, uint64(len(hashes)) * (hash.Size + commitDataSize)} if extraEdgesCount > 0 { chunkSignatures = append(chunkSignatures, extraEdgeListSignature) chunkSizes = append(chunkSizes, uint64(extraEdgesCount)*4) @@ -88,7 +89,11 @@ func (e *Encoder) prepare(idx Index, hashes []plumbing.Hash) (hashToIndex map[pl func (e *Encoder) encodeFileHeader(chunkCount int) (err error) { if _, err = e.Write(commitFileSignature); err == nil { - _, err = e.Write([]byte{1, 1, byte(chunkCount), 0}) + version := byte(1) + if hash.CryptoType == crypto.SHA256 { + version = byte(2) + } + _, err = e.Write([]byte{1, version, byte(chunkCount), 0}) } return } diff --git a/plumbing/format/commitgraph/file.go b/plumbing/format/commitgraph/file.go index 1d25238..17c1c5d 100644 --- a/plumbing/format/commitgraph/file.go +++ b/plumbing/format/commitgraph/file.go @@ -2,12 +2,14 @@ package commitgraph import ( "bytes" + "crypto" encbin "encoding/binary" "errors" "io" "time" "github.com/go-git/go-git/v5/plumbing" + "github.com/go-git/go-git/v5/plumbing/hash" "github.com/go-git/go-git/v5/utils/binary" ) @@ -36,6 +38,8 @@ var ( parentLast = uint32(0x80000000) ) +const commitDataSize = 16 + type fileIndex struct { reader io.ReaderAt fanout [256]int @@ -65,7 +69,7 @@ func OpenFileIndex(reader io.ReaderAt) (Index, error) { func (fi *fileIndex) verifyFileHeader() error { // Verify file signature - var signature = make([]byte, 4) + signature := make([]byte, 4) if _, err := fi.reader.ReadAt(signature, 0); err != nil { return err } @@ -74,22 +78,31 @@ func (fi *fileIndex) verifyFileHeader() error { } // Read and verify the file header - var header = make([]byte, 4) + header := make([]byte, 4) if _, err := fi.reader.ReadAt(header, 4); err != nil { return err } if header[0] != 1 { return ErrUnsupportedVersion } - if header[1] != 1 { - return ErrUnsupportedHash + if hash.CryptoType == crypto.SHA1 { + if header[1] != 1 { + return ErrUnsupportedVersion + } + } else if hash.CryptoType == crypto.SHA256 { + if header[1] != 2 { + return ErrUnsupportedVersion + } + } else { + // Unknown hash type + return ErrUnsupportedVersion } return nil } func (fi *fileIndex) readChunkHeaders() error { - var chunkID = make([]byte, 4) + chunkID := make([]byte, 4) for i := 0; ; i++ { chunkHeader := io.NewSectionReader(fi.reader, 8+(int64(i)*12), 12) if _, err := io.ReadAtLeast(chunkHeader, chunkID, 4); err != nil { @@ -148,7 +161,7 @@ func (fi *fileIndex) GetIndexByHash(h plumbing.Hash) (int, error) { high := fi.fanout[h[0]] for low < high { mid := (low + high) >> 1 - offset := fi.oidLookupOffset + int64(mid)*20 + offset := fi.oidLookupOffset + int64(mid)*hash.Size if _, err := fi.reader.ReadAt(oid[:], offset); err != nil { return 0, err } @@ -170,8 +183,8 @@ func (fi *fileIndex) GetCommitDataByIndex(idx int) (*CommitData, error) { return nil, plumbing.ErrObjectNotFound } - offset := fi.commitDataOffset + int64(idx)*36 - commitDataReader := io.NewSectionReader(fi.reader, offset, 36) + offset := fi.commitDataOffset + int64(idx)*(hash.Size+commitDataSize) + commitDataReader := io.NewSectionReader(fi.reader, offset, hash.Size+commitDataSize) treeHash, err := binary.ReadHash(commitDataReader) if err != nil { @@ -237,7 +250,7 @@ func (fi *fileIndex) getHashesFromIndexes(indexes []int) ([]plumbing.Hash, error return nil, ErrMalformedCommitGraphFile } - offset := fi.oidLookupOffset + int64(idx)*20 + offset := fi.oidLookupOffset + int64(idx)*hash.Size if _, err := fi.reader.ReadAt(hashes[i][:], offset); err != nil { return nil, err } @@ -250,8 +263,8 @@ func (fi *fileIndex) getHashesFromIndexes(indexes []int) ([]plumbing.Hash, error func (fi *fileIndex) Hashes() []plumbing.Hash { hashes := make([]plumbing.Hash, fi.fanout[0xff]) for i := 0; i < fi.fanout[0xff]; i++ { - offset := fi.oidLookupOffset + int64(i)*20 - if n, err := fi.reader.ReadAt(hashes[i][:], offset); err != nil || n < 20 { + offset := fi.oidLookupOffset + int64(i)*hash.Size + if n, err := fi.reader.ReadAt(hashes[i][:], offset); err != nil || n < hash.Size { return nil } } -- cgit