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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 Mode, dataref string, path 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
}
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