mirror of
https://github.com/go-gitea/gitea
synced 2024-08-18 13:20:51 +02:00
244 lines
6.2 KiB
Go
244 lines
6.2 KiB
Go
|
// Copyright 2020 The Gitea Authors. All rights reserved.
|
||
|
// Use of this source code is governed by a MIT-style
|
||
|
// license that can be found in the LICENSE file.
|
||
|
|
||
|
// +build !gogit
|
||
|
|
||
|
package git
|
||
|
|
||
|
import (
|
||
|
"bufio"
|
||
|
"bytes"
|
||
|
"math"
|
||
|
"strconv"
|
||
|
)
|
||
|
|
||
|
// ReadBatchLine reads the header line from cat-file --batch
|
||
|
// We expect:
|
||
|
// <sha> SP <type> SP <size> LF
|
||
|
func ReadBatchLine(rd *bufio.Reader) (sha []byte, typ string, size int64, err error) {
|
||
|
sha, err = rd.ReadBytes(' ')
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
sha = sha[:len(sha)-1]
|
||
|
|
||
|
typ, err = rd.ReadString(' ')
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
typ = typ[:len(typ)-1]
|
||
|
|
||
|
var sizeStr string
|
||
|
sizeStr, err = rd.ReadString('\n')
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
|
||
|
size, err = strconv.ParseInt(sizeStr[:len(sizeStr)-1], 10, 64)
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// ReadTagObjectID reads a tag object ID hash from a cat-file --batch stream, throwing away the rest of the stream.
|
||
|
func ReadTagObjectID(rd *bufio.Reader, size int64) (string, error) {
|
||
|
id := ""
|
||
|
var n int64
|
||
|
headerLoop:
|
||
|
for {
|
||
|
line, err := rd.ReadBytes('\n')
|
||
|
if err != nil {
|
||
|
return "", err
|
||
|
}
|
||
|
n += int64(len(line))
|
||
|
idx := bytes.Index(line, []byte{' '})
|
||
|
if idx < 0 {
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
if string(line[:idx]) == "object" {
|
||
|
id = string(line[idx+1 : len(line)-1])
|
||
|
break headerLoop
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Discard the rest of the tag
|
||
|
discard := size - n
|
||
|
for discard > math.MaxInt32 {
|
||
|
_, err := rd.Discard(math.MaxInt32)
|
||
|
if err != nil {
|
||
|
return id, err
|
||
|
}
|
||
|
discard -= math.MaxInt32
|
||
|
}
|
||
|
_, err := rd.Discard(int(discard))
|
||
|
return id, err
|
||
|
}
|
||
|
|
||
|
// ReadTreeID reads a tree ID from a cat-file --batch stream, throwing away the rest of the stream.
|
||
|
func ReadTreeID(rd *bufio.Reader, size int64) (string, error) {
|
||
|
id := ""
|
||
|
var n int64
|
||
|
headerLoop:
|
||
|
for {
|
||
|
line, err := rd.ReadBytes('\n')
|
||
|
if err != nil {
|
||
|
return "", err
|
||
|
}
|
||
|
n += int64(len(line))
|
||
|
idx := bytes.Index(line, []byte{' '})
|
||
|
if idx < 0 {
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
if string(line[:idx]) == "tree" {
|
||
|
id = string(line[idx+1 : len(line)-1])
|
||
|
break headerLoop
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Discard the rest of the commit
|
||
|
discard := size - n
|
||
|
for discard > math.MaxInt32 {
|
||
|
_, err := rd.Discard(math.MaxInt32)
|
||
|
if err != nil {
|
||
|
return id, err
|
||
|
}
|
||
|
discard -= math.MaxInt32
|
||
|
}
|
||
|
_, err := rd.Discard(int(discard))
|
||
|
return id, err
|
||
|
}
|
||
|
|
||
|
// git tree files are a list:
|
||
|
// <mode-in-ascii> SP <fname> NUL <20-byte SHA>
|
||
|
//
|
||
|
// Unfortunately this 20-byte notation is somewhat in conflict to all other git tools
|
||
|
// Therefore we need some method to convert these 20-byte SHAs to a 40-byte SHA
|
||
|
|
||
|
// constant hextable to help quickly convert between 20byte and 40byte hashes
|
||
|
const hextable = "0123456789abcdef"
|
||
|
|
||
|
// to40ByteSHA converts a 20-byte SHA in a 40-byte slice into a 40-byte sha in place
|
||
|
// without allocations. This is at least 100x quicker that hex.EncodeToString
|
||
|
// NB This requires that sha is a 40-byte slice
|
||
|
func to40ByteSHA(sha []byte) []byte {
|
||
|
for i := 19; i >= 0; i-- {
|
||
|
v := sha[i]
|
||
|
vhi, vlo := v>>4, v&0x0f
|
||
|
shi, slo := hextable[vhi], hextable[vlo]
|
||
|
sha[i*2], sha[i*2+1] = shi, slo
|
||
|
}
|
||
|
return sha
|
||
|
}
|
||
|
|
||
|
// ParseTreeLineSkipMode reads an entry from a tree in a cat-file --batch stream
|
||
|
// This simply skips the mode - saving a substantial amount of time and carefully avoids allocations - except where fnameBuf is too small.
|
||
|
// It is recommended therefore to pass in an fnameBuf large enough to avoid almost all allocations
|
||
|
//
|
||
|
// Each line is composed of:
|
||
|
// <mode-in-ascii-dropping-initial-zeros> SP <fname> NUL <20-byte SHA>
|
||
|
//
|
||
|
// We don't attempt to convert the 20-byte SHA to 40-byte SHA to save a lot of time
|
||
|
func ParseTreeLineSkipMode(rd *bufio.Reader, fnameBuf, shaBuf []byte) (fname, sha []byte, n int, err error) {
|
||
|
var readBytes []byte
|
||
|
// Skip the Mode
|
||
|
readBytes, err = rd.ReadSlice(' ') // NB: DOES NOT ALLOCATE SIMPLY RETURNS SLICE WITHIN READER BUFFER
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
n += len(readBytes)
|
||
|
|
||
|
// Deal with the fname
|
||
|
readBytes, err = rd.ReadSlice('\x00')
|
||
|
copy(fnameBuf, readBytes)
|
||
|
if len(fnameBuf) > len(readBytes) {
|
||
|
fnameBuf = fnameBuf[:len(readBytes)] // cut the buf the correct size
|
||
|
} else {
|
||
|
fnameBuf = append(fnameBuf, readBytes[len(fnameBuf):]...) // extend the buf and copy in the missing bits
|
||
|
}
|
||
|
for err == bufio.ErrBufferFull { // Then we need to read more
|
||
|
readBytes, err = rd.ReadSlice('\x00')
|
||
|
fnameBuf = append(fnameBuf, readBytes...) // there is little point attempting to avoid allocations here so just extend
|
||
|
}
|
||
|
n += len(fnameBuf)
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
fnameBuf = fnameBuf[:len(fnameBuf)-1] // Drop the terminal NUL
|
||
|
fname = fnameBuf // set the returnable fname to the slice
|
||
|
|
||
|
// Now deal with the 20-byte SHA
|
||
|
idx := 0
|
||
|
for idx < 20 {
|
||
|
read := 0
|
||
|
read, err = rd.Read(shaBuf[idx:20])
|
||
|
n += read
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
idx += read
|
||
|
}
|
||
|
sha = shaBuf
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// ParseTreeLine reads an entry from a tree in a cat-file --batch stream
|
||
|
// This carefully avoids allocations - except where fnameBuf is too small.
|
||
|
// It is recommended therefore to pass in an fnameBuf large enough to avoid almost all allocations
|
||
|
//
|
||
|
// Each line is composed of:
|
||
|
// <mode-in-ascii-dropping-initial-zeros> SP <fname> NUL <20-byte SHA>
|
||
|
//
|
||
|
// We don't attempt to convert the 20-byte SHA to 40-byte SHA to save a lot of time
|
||
|
func ParseTreeLine(rd *bufio.Reader, modeBuf, fnameBuf, shaBuf []byte) (mode, fname, sha []byte, n int, err error) {
|
||
|
var readBytes []byte
|
||
|
|
||
|
// Read the Mode
|
||
|
readBytes, err = rd.ReadSlice(' ')
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
n += len(readBytes)
|
||
|
copy(modeBuf, readBytes)
|
||
|
if len(modeBuf) > len(readBytes) {
|
||
|
modeBuf = modeBuf[:len(readBytes)]
|
||
|
} else {
|
||
|
modeBuf = append(modeBuf, readBytes[len(modeBuf):]...)
|
||
|
|
||
|
}
|
||
|
mode = modeBuf[:len(modeBuf)-1] // Drop the SP
|
||
|
|
||
|
// Deal with the fname
|
||
|
readBytes, err = rd.ReadSlice('\x00')
|
||
|
copy(fnameBuf, readBytes)
|
||
|
if len(fnameBuf) > len(readBytes) {
|
||
|
fnameBuf = fnameBuf[:len(readBytes)]
|
||
|
} else {
|
||
|
fnameBuf = append(fnameBuf, readBytes[len(fnameBuf):]...)
|
||
|
}
|
||
|
for err == bufio.ErrBufferFull {
|
||
|
readBytes, err = rd.ReadSlice('\x00')
|
||
|
fnameBuf = append(fnameBuf, readBytes...)
|
||
|
}
|
||
|
n += len(fnameBuf)
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
fnameBuf = fnameBuf[:len(fnameBuf)-1]
|
||
|
fname = fnameBuf
|
||
|
|
||
|
// Deal with the 20-byte SHA
|
||
|
idx := 0
|
||
|
for idx < 20 {
|
||
|
read := 0
|
||
|
read, err = rd.Read(shaBuf[idx:20])
|
||
|
n += read
|
||
|
if err != nil {
|
||
|
return
|
||
|
}
|
||
|
idx += read
|
||
|
}
|
||
|
sha = shaBuf
|
||
|
return
|
||
|
}
|