1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
|
// 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.
package git
import (
"bufio"
"bytes"
"context"
"fmt"
"io"
"math"
"runtime"
"strconv"
"strings"
"code.gitea.io/gitea/modules/log"
"github.com/djherbis/buffer"
"github.com/djherbis/nio/v3"
)
// WriteCloserError wraps an io.WriteCloser with an additional CloseWithError function
type WriteCloserError interface {
io.WriteCloser
CloseWithError(err error) error
}
// EnsureValidGitRepository runs git rev-parse in the repository path - thus ensuring that the repository is a valid repository.
// Run before opening git cat-file.
// This is needed otherwise the git cat-file will hang for invalid repositories.
func EnsureValidGitRepository(ctx context.Context, repoPath string) error {
stderr := strings.Builder{}
err := NewCommand(ctx, "rev-parse").
SetDescription(fmt.Sprintf("%s rev-parse [repo_path: %s]", GitExecutable, repoPath)).
RunWithContext(&RunContext{
Timeout: -1,
Dir: repoPath,
Stderr: &stderr,
})
if err != nil {
return ConcatenateError(err, (&stderr).String())
}
return nil
}
// CatFileBatchCheck opens git cat-file --batch-check in the provided repo and returns a stdin pipe, a stdout reader and cancel function
func CatFileBatchCheck(ctx context.Context, repoPath string) (WriteCloserError, *bufio.Reader, func()) {
batchStdinReader, batchStdinWriter := io.Pipe()
batchStdoutReader, batchStdoutWriter := io.Pipe()
ctx, ctxCancel := context.WithCancel(ctx)
closed := make(chan struct{})
cancel := func() {
ctxCancel()
_ = batchStdoutReader.Close()
_ = batchStdinWriter.Close()
<-closed
}
_, filename, line, _ := runtime.Caller(2)
filename = strings.TrimPrefix(filename, callerPrefix)
go func() {
stderr := strings.Builder{}
err := NewCommand(ctx, "cat-file", "--batch-check").
SetDescription(fmt.Sprintf("%s cat-file --batch-check [repo_path: %s] (%s:%d)", GitExecutable, repoPath, filename, line)).
RunWithContext(&RunContext{
Timeout: -1,
Dir: repoPath,
Stdin: batchStdinReader,
Stdout: batchStdoutWriter,
Stderr: &stderr,
})
if err != nil {
_ = batchStdoutWriter.CloseWithError(ConcatenateError(err, (&stderr).String()))
_ = batchStdinReader.CloseWithError(ConcatenateError(err, (&stderr).String()))
} else {
_ = batchStdoutWriter.Close()
_ = batchStdinReader.Close()
}
close(closed)
}()
// For simplicities sake we'll use a buffered reader to read from the cat-file --batch-check
batchReader := bufio.NewReader(batchStdoutReader)
return batchStdinWriter, batchReader, cancel
}
// CatFileBatch opens git cat-file --batch in the provided repo and returns a stdin pipe, a stdout reader and cancel function
func CatFileBatch(ctx context.Context, repoPath string) (WriteCloserError, *bufio.Reader, func()) {
// We often want to feed the commits in order into cat-file --batch, followed by their trees and sub trees as necessary.
// so let's create a batch stdin and stdout
batchStdinReader, batchStdinWriter := io.Pipe()
batchStdoutReader, batchStdoutWriter := nio.Pipe(buffer.New(32 * 1024))
ctx, ctxCancel := context.WithCancel(ctx)
closed := make(chan struct{})
cancel := func() {
ctxCancel()
_ = batchStdinWriter.Close()
_ = batchStdoutReader.Close()
<-closed
}
_, filename, line, _ := runtime.Caller(2)
filename = strings.TrimPrefix(filename, callerPrefix)
go func() {
stderr := strings.Builder{}
err := NewCommand(ctx, "cat-file", "--batch").
SetDescription(fmt.Sprintf("%s cat-file --batch [repo_path: %s] (%s:%d)", GitExecutable, repoPath, filename, line)).
RunWithContext(&RunContext{
Timeout: -1,
Dir: repoPath,
Stdin: batchStdinReader,
Stdout: batchStdoutWriter,
Stderr: &stderr,
})
if err != nil {
_ = batchStdoutWriter.CloseWithError(ConcatenateError(err, (&stderr).String()))
_ = batchStdinReader.CloseWithError(ConcatenateError(err, (&stderr).String()))
} else {
_ = batchStdoutWriter.Close()
_ = batchStdinReader.Close()
}
close(closed)
}()
// For simplicities sake we'll us a buffered reader to read from the cat-file --batch
batchReader := bufio.NewReaderSize(batchStdoutReader, 32*1024)
return batchStdinWriter, batchReader, cancel
}
// ReadBatchLine reads the header line from cat-file --batch
// We expect:
// <sha> SP <type> SP <size> LF
// sha is a 40byte not 20byte here
func ReadBatchLine(rd *bufio.Reader) (sha []byte, typ string, size int64, err error) {
typ, err = rd.ReadString('\n')
if err != nil {
return
}
if len(typ) == 1 {
typ, err = rd.ReadString('\n')
if err != nil {
return
}
}
idx := strings.IndexByte(typ, ' ')
if idx < 0 {
log.Debug("missing space typ: %s", typ)
err = ErrNotExist{ID: string(sha)}
return
}
sha = []byte(typ[:idx])
typ = typ[idx+1:]
idx = strings.IndexByte(typ, ' ')
if idx < 0 {
err = ErrNotExist{ID: string(sha)}
return
}
sizeStr := typ[idx+1 : len(typ)-1]
typ = typ[:idx]
size, err = strconv.ParseInt(sizeStr, 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 + 1
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 + 1
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 into a 40-byte sha. Input and output can be the
// same 40 byte slice to support in place conversion without allocations.
// This is at least 100x quicker that hex.EncodeToString
// NB This requires that out is a 40-byte slice
func To40ByteSHA(sha, out []byte) []byte {
for i := 19; i >= 0; i-- {
v := sha[i]
vhi, vlo := v>>4, v&0x0f
shi, slo := hextable[vhi], hextable[vlo]
out[i*2], out[i*2+1] = shi, slo
}
return out
}
// 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 & fname
readBytes, err = rd.ReadSlice('\x00')
if err != nil {
return
}
idx := bytes.IndexByte(readBytes, ' ')
if idx < 0 {
log.Debug("missing space in readBytes ParseTreeLine: %s", readBytes)
err = &ErrNotExist{}
return
}
n += idx + 1
copy(modeBuf, readBytes[:idx])
if len(modeBuf) >= idx {
modeBuf = modeBuf[:idx]
} else {
modeBuf = append(modeBuf, readBytes[len(modeBuf):idx]...)
}
mode = modeBuf
readBytes = readBytes[idx+1:]
// Deal with the fname
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
}
var callerPrefix string
func init() {
_, filename, _, _ := runtime.Caller(0)
callerPrefix = strings.TrimSuffix(filename, "modules/git/batch_reader.go")
}
|