package libfastimport import ( "bufio" "fmt" "io" "git.lukeshu.com/go/libfastimport/textproto" ) // A Backend is something that consumes a fast-import stream; the // Backend object provides methods for writing to it. type Backend struct { fastImportClose io.Closer fastImportFlush *bufio.Writer fastImportWrite *textproto.FIWriter catBlob *textproto.CatBlobReader inCommit bool err error onErr func(error) error } func NewBackend(fastImport io.WriteCloser, catBlob io.Reader, onErr func(error) error) *Backend { ret := &Backend{} ret.fastImportClose = fastImport ret.fastImportFlush = bufio.NewWriter(fastImport) ret.fastImportWrite = textproto.NewFIWriter(ret.fastImportFlush) if catBlob != nil { ret.catBlob = textproto.NewCatBlobReader(catBlob) } ret.onErr = func(err error) error { ret.err = err // Close the underlying writer, but don't let the // error mask the previous error. err = ret.fastImportClose.Close() if ret.err == nil { ret.err = err } if onErr != nil { ret.err = onErr(ret.err) } return ret.err } return ret } // will panic if Cmd is a type that may only be used in a commit but // we aren't in a commit. func (b *Backend) Do(cmd Cmd) error { if b.err == nil { return b.err } switch cmd.fiCmdClass() { case cmdClassCommand: _, b.inCommit = cmd.(CmdCommit) case cmdClassCommit: if !b.inCommit { panic(fmt.Errorf("Cannot issue commit sub-command outside of a commit: %[1]T(%#[1]v)", cmd)) } case cmdClassComment: /* do nothing */ default: panic(fmt.Errorf("invalid cmdClass: %d", cmd.fiCmdClass())) } err := cmd.fiCmdWrite(b.fastImportWrite) if err != nil { return b.onErr(err) } err = b.fastImportFlush.Flush() if err != nil { return b.onErr(err) } if _, isDone := cmd.(CmdDone); isDone { return b.onErr(nil) } return nil } func (b *Backend) GetMark(cmd CmdGetMark) (sha1 string, err error) { err = b.Do(cmd) if err != nil { return } line, err := b.catBlob.ReadLine() if err != nil { err = b.onErr(err) return } sha1, err = cbpGetMark(line) if err != nil { err = b.onErr(err) } return } func (b *Backend) CatBlob(cmd CmdCatBlob) (sha1 string, data string, err error) { err = b.Do(cmd) if err != nil { return } line, err := b.catBlob.ReadLine() if err != nil { err = b.onErr(err) return } sha1, data, err = cbpCatBlob(line) if err != nil { err = b.onErr(err) } return } func (b *Backend) Ls(cmd CmdLs) (mode textproto.Mode, dataref string, path textproto.Path, err error) { err = b.Do(cmd) if err != nil { return } line, err := b.catBlob.ReadLine() if err != nil { err = b.onErr(err) return } mode, dataref, path, err = cbpLs(line) if err != nil { err = b.onErr(err) } return }