package index import ( "fmt" "io" "gopkg.in/src-d/go-git.v4/core" "gopkg.in/src-d/go-git.v4/formats/idxfile" "gopkg.in/src-d/go-git.v4/formats/packfile" ) // Index is a database of objects and their offset in a packfile. // Objects are identified by their hash. type Index map[core.Hash]int64 // NewFromIdx returns a new index from an idx file reader. func NewFromIdx(r io.Reader) (Index, error) { d := idxfile.NewDecoder(r) idx := &idxfile.Idxfile{} err := d.Decode(idx) if err != nil { return nil, err } ind := make(Index) for _, e := range idx.Entries { if _, ok := ind[e.Hash]; ok { return nil, fmt.Errorf("duplicated hash: %s", e.Hash) } ind[e.Hash] = int64(e.Offset) } return ind, nil } // NewFrompackfile returns a new index from a packfile reader. func NewFromPackfile(rs io.ReadSeeker) (Index, error) { index := make(Index) r := packfile.NewSeekable(rs) p := packfile.NewParser(r) count, err := p.ReadHeader() if err != nil { return nil, err } for i := 0; i < int(count); i++ { offset, err := r.Offset() if err != nil { return nil, err } obj := &core.MemoryObject{} if err := p.FillObject(obj); err != nil { return nil, err } err = r.Remember(offset, obj) if err != nil { return nil, err } err = index.Set(obj.Hash(), offset) if err != nil { return nil, err } } return index, nil } // Get returns the offset that an object has the packfile. func (i Index) Get(h core.Hash) (int64, error) { o, ok := i[h] if !ok { return 0, core.ErrObjectNotFound } return o, nil } // Set adds a new hash-offset pair to the index, or substitutes an existing one. func (i Index) Set(h core.Hash, o int64) error { if _, ok := i[h]; ok { return fmt.Errorf("index.Set failed: duplicated key: %s", h) } i[h] = o return nil }