diff options
author | Andrew Thornton <art27@cantab.net> | 2023-09-30 11:41:23 +0100 |
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committer | Andrew Thornton <art27@cantab.net> | 2023-10-08 09:38:00 +0100 |
commit | 946bb8183643bdda90810fc48e450a008894b244 (patch) | |
tree | ee2718e1ac621c88716068842e4ae38ed69862e8 /plumbing/format/commitgraph/v2/chain.go | |
parent | 19fe126d8889134e6224717a756745eed9985e22 (diff) | |
download | go-git-946bb8183643bdda90810fc48e450a008894b244.tar.gz |
plumbing: commitgraph, fix types and handle commit-graph-chains
Unfortunately the original variant makes some incorrect typing
assumptions about commit-graphs which make handling graph chains
difficult to do correctly. This creates a new subpackage and deprecates
the old one. It then adds support commit graph chains.
Signed-off-by: Andrew Thornton <art27@cantab.net>
Diffstat (limited to 'plumbing/format/commitgraph/v2/chain.go')
-rw-r--r-- | plumbing/format/commitgraph/v2/chain.go | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/plumbing/format/commitgraph/v2/chain.go b/plumbing/format/commitgraph/v2/chain.go new file mode 100644 index 0000000..8da60d0 --- /dev/null +++ b/plumbing/format/commitgraph/v2/chain.go @@ -0,0 +1,100 @@ +package v2 + +import ( + "bufio" + "io" + "path" + + "github.com/go-git/go-billy/v5" + "github.com/go-git/go-git/v5/plumbing" +) + +// OpenChainFile reads a commit chain file and returns a slice of the hashes within it +// +// Commit-Graph chains are described at https://git-scm.com/docs/commit-graph +// and are new line separated list of graph file hashes, oldest to newest. +// +// This function simply reads the file and returns the hashes as a slice. +func OpenChainFile(r io.Reader) ([]string, error) { + if r == nil { + return nil, io.ErrUnexpectedEOF + } + bufRd := bufio.NewReader(r) + chain := make([]string, 0, 8) + for { + line, err := bufRd.ReadSlice('\n') + if err != nil { + if err == io.EOF { + break + } + return nil, err + } + + hashStr := string(line[:len(line)-1]) + if !plumbing.IsHash(hashStr) { + return nil, ErrMalformedCommitGraphFile + } + chain = append(chain, hashStr) + } + return chain, nil +} + +// OpenChainOrFileIndex expects a billy.Filesystem representing a .git directory. +// It will first attempt to read a commit-graph index file, before trying to read a +// commit-graph chain file and its index files. If neither are present, an error is returned. +// Otherwise an Index will be returned. +// +// See: https://git-scm.com/docs/commit-graph +func OpenChainOrFileIndex(fs billy.Filesystem) (Index, error) { + file, err := fs.Open(path.Join("objects", "info", "commit-graph")) + if err != nil { + // try to open a chain file + return OpenChainIndex(fs) + } + + index, err := OpenFileIndex(file) + if err != nil { + // Ignore any file closing errors and return the error from OpenFileIndex instead + _ = file.Close() + return nil, err + } + return index, nil +} + +// OpenChainIndex expects a billy.Filesystem representing a .git directory. +// It will read a commit-graph chain file and return a coalesced index. +// If the chain file or a graph in that chain is not present, an error is returned. +// +// See: https://git-scm.com/docs/commit-graph +func OpenChainIndex(fs billy.Filesystem) (Index, error) { + chainFile, err := fs.Open(path.Join("objects", "info", "commit-graphs", "commit-graph-chain")) + if err != nil { + return nil, err + } + + chain, err := OpenChainFile(chainFile) + _ = chainFile.Close() + if err != nil { + return nil, err + } + + var index Index + for _, hash := range chain { + + file, err := fs.Open(path.Join("objects", "info", "commit-graphs", "graph-"+hash+".graph")) + if err != nil { + // Ignore all other file closing errors and return the error from opening the last file in the graph + _ = index.Close() + return nil, err + } + + index, err = OpenFileIndexWithParent(file, index) + if err != nil { + // Ignore file closing errors and return the error from OpenFileIndex instead + _ = index.Close() + return nil, err + } + } + + return index, nil +} |