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package libfastimport
import (
"bufio"
"fmt"
"io"
"strconv"
"strings"
"git.lukeshu.com/go/libfastimport/textproto"
)
type UnsupportedCommand string
func (e UnsupportedCommand) Error() string {
return "Unsupported command: " + string(e)
}
// A Frontend is something that produces a fast-import stream; the
// Frontend object provides methods for reading from it.
type Frontend struct {
fir *textproto.FIReader
cbw *textproto.CatBlobWriter
w *bufio.Writer
cmd chan Cmd
err error
}
func NewFrontend(fastImport io.Reader, catBlob io.Writer) *Frontend {
ret := &Frontend{}
ret.fir = textproto.NewFIReader(fastImport)
if catBlob != nil {
ret.w = bufio.NewWriter(catBlob)
ret.cbw = textproto.NewCatBlobWriter(ret.w)
}
ret.cmd = make(chan Cmd)
go func() {
ret.err = ret.parse()
close(ret.cmd)
}()
return ret
}
func (f *Frontend) nextLine() (line string, err error) {
for {
line, err = f.fir.ReadLine()
if err != nil {
return
}
switch {
case strings.HasPrefix(line, "#"):
f.cmd <- CmdComment{Comment: line[1:]}
case strings.HasPrefix(line, "cat-blob "):
// 'cat-blob' SP <dataref> LF
dataref := strings.TrimSuffix(strings.TrimPrefix(line, "cat-blob "), "\n")
f.cmd <- CmdCatBlob{DataRef: dataref}
case strings.HasPrefix(line, "get-mark :"):
// 'get-mark' SP ':' <idnum> LF
strIdnum := strings.TrimSuffix(strings.TrimPrefix(line, "get-mark :"), "\n")
var nIdnum int
nIdnum, err = strconv.Atoi(strIdnum)
if err != nil {
line = ""
err = fmt.Errorf("get-mark: %v", err)
return
}
f.cmd <- CmdGetMark{Mark: nIdnum}
default:
return
}
}
}
func parse_data(line string) (data string, err error) {
nl := strings.IndexByte(line, '\n')
if nl < 0 {
return "", fmt.Errorf("data: expected newline: %v", data)
}
head := line[:nl]
rest := line[nl+1:]
if !strings.HasPrefix(head, "data ") {
return "", fmt.Errorf("data: could not parse: %v", data)
}
if strings.HasPrefix(head, "data <<") {
// Delimited format
delim := strings.TrimPrefix(head, "data <<")
suffix := "\n" + delim + "\n"
if !strings.HasSuffix(rest, suffix) {
return "", fmt.Errorf("data: did not find suffix: %v", suffix)
}
data = strings.TrimSuffix(rest, suffix)
} else {
// Exact byte count format
strN := strings.TrimSuffix(head, "data ")
intN, err := strconv.Atoi(strN)
if err != nil {
return "", err
}
if intN != len(rest) {
panic("FIReader should not have let this happen")
}
data = rest
}
return
}
func (f *Frontend) parse() error {
line, err := f.nextLine()
if err != nil {
return err
}
for {
switch {
case line == "blob\n":
// 'blob' LF
// mark?
// data
c := CmdBlob{}
line, err = f.nextLine()
if err != nil {
return err
}
if strings.HasPrefix(line, "mark :") {
str := strings.TrimSuffix(strings.TrimPrefix(line, "mark :"), "\n")
c.Mark, err = strconv.Atoi(str)
if err != nil {
return err
}
line, err = f.nextLine()
if err != nil {
return err
}
}
if !strings.HasPrefix(line, "data ") {
return fmt.Errorf("Unexpected command in blob: %q", line)
}
c.Data, err = parse_data(line)
if err != nil {
return err
}
f.cmd <- c
case line == "checkpoint\n":
f.cmd <- CmdCheckpoint{}
case line == "done\n":
f.cmd <- CmdDone{}
case strings.HasPrefix(line, "commit "):
// 'commit' SP <ref> LF
// mark?
// ('author' (SP <name>)? SP LT <email> GT SP <when> LF)?
// 'committer' (SP <name>)? SP LT <email> GT SP <when> LF
// data
// ('from' SP <commit-ish> LF)?
// ('merge' SP <commit-ish> LF)*
// (filemodify | filedelete | filecopy | filerename | filedeleteall | notemodify)*
// TODO
case strings.HasPrefix(line, "feature "):
// 'feature' SP <feature> ('=' <argument>)? LF
// TODO
case strings.HasPrefix(line, "ls "):
// 'ls' SP <dataref> SP <path> LF
// TODO
case strings.HasPrefix(line, "option "):
// 'option' SP <option> LF
// TODO
case strings.HasPrefix(line, "progress "):
// 'progress' SP <any> LF
str := strings.TrimSuffix(strings.TrimPrefix(line, "progress "), "\n")
f.cmd <- CmdProgress{Str: str}
case strings.HasPrefix(line, "reset "):
// 'reset' SP <ref> LF
// ('from' SP <commit-ish> LF)?
// TODO
case strings.HasPrefix(line, "tag "):
// 'tag' SP <name> LF
// 'from' SP <commit-ish> LF
// 'tagger' (SP <name>)? SP LT <email> GT SP <when> LF
// data
// TODO
default:
return UnsupportedCommand(line)
}
line, err = f.nextLine()
if err != nil {
return err
}
}
}
func (f *Frontend) ReadCmd() (Cmd, error) {
cmd, ok := <-f.cmd
if ok {
return cmd, nil
}
return nil, f.err
}
func (f *Frontend) RespondGetMark(sha1 string) error {
// TODO
return f.w.Flush()
}
func (f *Frontend) RespondCatBlob(sha1 string, data string) error {
// TODO
return f.w.Flush()
}
func (f *Frontend) RespondLs(mode textproto.Mode, dataref string, path textproto.Path) error {
// TODO
return f.w.Flush()
}
|
