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author | Filip Navara <filip.navara@gmail.com> | 2018-11-28 01:29:41 +0100 |
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committer | Máximo Cuadros <mcuadros@gmail.com> | 2018-11-28 01:29:41 +0100 |
commit | 8f52c5099e7fe4a2519920a7bbf5a9bb52ff9cec (patch) | |
tree | 6b08348c45ad42e1979d35b43908d5077d99cf78 /plumbing/format/packfile/scanner.go | |
parent | 3dbfb89e0f5bce0008724e547b999fe3af9f60db (diff) | |
download | go-git-8f52c5099e7fe4a2519920a7bbf5a9bb52ff9cec.tar.gz |
plumbing: format/packfile, performance optimizations for reading large commit histories (#963)
Signed-off-by: Filip Navara <navara@emclient.com>
Diffstat (limited to 'plumbing/format/packfile/scanner.go')
-rw-r--r-- | plumbing/format/packfile/scanner.go | 46 |
1 files changed, 42 insertions, 4 deletions
diff --git a/plumbing/format/packfile/scanner.go b/plumbing/format/packfile/scanner.go index 6fc183b..614b0d1 100644 --- a/plumbing/format/packfile/scanner.go +++ b/plumbing/format/packfile/scanner.go @@ -138,14 +138,52 @@ func (s *Scanner) readCount() (uint32, error) { return binary.ReadUint32(s.r) } +// SeekObjectHeader seeks to specified offset and returns the ObjectHeader +// for the next object in the reader +func (s *Scanner) SeekObjectHeader(offset int64) (*ObjectHeader, error) { + // if seeking we assume that you are not interested in the header + if s.version == 0 { + s.version = VersionSupported + } + + if _, err := s.r.Seek(offset, io.SeekStart); err != nil { + return nil, err + } + + h, err := s.nextObjectHeader() + if err != nil { + return nil, err + } + + h.Offset = offset + return h, nil +} + // NextObjectHeader returns the ObjectHeader for the next object in the reader func (s *Scanner) NextObjectHeader() (*ObjectHeader, error) { - defer s.Flush() - if err := s.doPending(); err != nil { return nil, err } + offset, err := s.r.Seek(0, io.SeekCurrent) + if err != nil { + return nil, err + } + + h, err := s.nextObjectHeader() + if err != nil { + return nil, err + } + + h.Offset = offset + return h, nil +} + +// nextObjectHeader returns the ObjectHeader for the next object in the reader +// without the Offset field +func (s *Scanner) nextObjectHeader() (*ObjectHeader, error) { + defer s.Flush() + s.crc.Reset() h := &ObjectHeader{} @@ -308,7 +346,7 @@ var byteSlicePool = sync.Pool{ // SeekFromStart sets a new offset from start, returns the old position before // the change. func (s *Scanner) SeekFromStart(offset int64) (previous int64, err error) { - // if seeking we assume that you are not interested on the header + // if seeking we assume that you are not interested in the header if s.version == 0 { s.version = VersionSupported } @@ -385,7 +423,7 @@ type bufferedSeeker struct { } func (r *bufferedSeeker) Seek(offset int64, whence int) (int64, error) { - if whence == io.SeekCurrent { + if whence == io.SeekCurrent && offset == 0 { current, err := r.r.Seek(offset, whence) if err != nil { return current, err |