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1 // Copyright 2016 The LUCI Authors. All rights reserved. | |
2 // Use of this source code is governed under the Apache License, Version 2.0 | |
3 // that can be found in the LICENSE file. | |
4 | |
5 // Write an ar archive file with BSD style filenames. | |
6 | |
7 package ar | |
8 | |
9 import ( | |
10 "errors" | |
11 "fmt" | |
12 "io" | |
13 "log" | |
14 "os" | |
15 ) | |
16 | |
17 const DEFAULT_MODTIME = 1447140471 | |
18 const DEFAULT_USER = 1000 | |
19 const DEFAULT_GROUP = 1000 | |
20 const DEFAULT_MODE = 0100640 // 100640 -- Octal | |
21 | |
22 type writerStage uint | |
23 | |
24 const ( | |
25 WRITE_HEADER writerStage = iota | |
M-A Ruel
2016/06/10 17:51:11
Use golang style; https://github.com/golang/go/wik
mithro
2016/06/14 10:57:52
Done.
| |
26 WRITE_BODY | |
27 WRITE_CLOSED | |
28 ) | |
29 | |
30 type Writer struct { | |
31 w io.Writer | |
32 stage writerStage | |
M-A Ruel
2016/06/10 17:51:11
make it a bool, unless you want to delay the "!<ar
mithro
2016/06/14 10:57:53
Done.
| |
33 | |
34 bytesrequired int64 | |
35 needspadding bool | |
36 } | |
37 | |
38 func NewWriter(w io.Writer) *Writer { | |
39 io.WriteString(w, "!<arch>\n") | |
M-A Ruel
2016/06/10 17:51:11
do not ignore the error here
or lazy write the hea
mithro
2016/06/14 10:57:52
Done.
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40 return &Writer{w: w, stage: WRITE_HEADER} | |
41 } | |
42 | |
43 func (aw *Writer) Close() error { | |
44 switch aw.stage { | |
M-A Ruel
2016/06/10 17:51:11
same comment as reader, just flush the file correc
mithro
2016/06/14 10:57:52
Most things report an error on a double Close() (a
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45 case WRITE_HEADER: | |
46 // Good | |
47 case WRITE_BODY: | |
48 return errors.New("usage error, writing a file") | |
49 case WRITE_CLOSED: | |
50 return errors.New("usage error, archive already closed") | |
51 default: | |
52 log.Fatalf("unknown writer mode: %d", aw.stage) | |
53 } | |
54 aw.stage = WRITE_CLOSED | |
55 aw.w = nil | |
56 return nil | |
57 } | |
58 | |
59 func (aw *Writer) wroteBytes(numbytes int64) error { | |
60 if numbytes > aw.bytesrequired { | |
61 log.Fatalf("to much data written, needed %d, got %d", aw.bytesre quired, numbytes) | |
62 } | |
63 | |
64 aw.bytesrequired -= numbytes | |
65 if aw.bytesrequired != 0 { | |
66 return nil | |
67 } | |
68 | |
69 // Padding to 16bit boundary | |
70 if aw.needspadding { | |
71 io.WriteString(aw.w, "\n") | |
72 aw.needspadding = false | |
73 } | |
74 aw.stage = WRITE_HEADER | |
75 return nil | |
76 } | |
77 | |
78 // Check you can write bytes to the ar at this moment. | |
M-A Ruel
2016/06/10 17:51:11
// canWriteContent returns nil if the stream is in
mithro
2016/06/14 10:57:53
Done.
| |
79 func (aw *Writer) checkWrite() error { | |
80 switch aw.stage { | |
M-A Ruel
2016/06/10 17:51:11
if a.r == nil {
return errors.New(...
}
if a.inH
mithro
2016/06/14 10:57:52
I still don't like this change, I personally think
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81 case WRITE_HEADER: | |
82 return errors.New("usage error, need to write header first") | |
83 // Good | |
84 case WRITE_BODY: | |
85 return nil | |
86 case WRITE_CLOSED: | |
87 return errors.New("usage error, archive closed") | |
88 default: | |
89 log.Fatalf("unknown writer mode: %d", aw.stage) | |
90 } | |
91 return nil | |
92 } | |
93 | |
94 // Check we have finished writing bytes | |
95 func (aw *Writer) checkFinished() { | |
96 if aw.bytesrequired != 0 { | |
97 log.Fatalf("didn't write enough bytes %d still needed, archive c orrupted", aw.bytesrequired) | |
M-A Ruel
2016/06/10 17:51:11
return errors.New()
then have the call sites retu
mithro
2016/06/14 10:57:52
Kinda done - see my comment previously.
| |
98 } | |
99 } | |
100 | |
101 func (aw *Writer) writePartial(data []byte) error { | |
102 err := aw.checkWrite() | |
M-A Ruel
2016/06/10 17:51:11
similar to reader, inline here and at other places
mithro
2016/06/14 10:57:52
Done.
| |
103 if err != nil { | |
104 return err | |
105 } | |
106 | |
107 datalen := int64(len(data)) | |
108 if datalen > aw.bytesrequired { | |
109 return fmt.Errorf("to much data, needed %d, got %d", aw.bytesreq uired, datalen) | |
110 } | |
111 | |
112 aw.w.Write(data) | |
113 aw.wroteBytes(datalen) | |
114 return nil | |
115 } | |
116 | |
117 func (aw *Writer) WriteReader(data io.Reader) error { | |
M-A Ruel
2016/06/10 17:51:11
https://golang.org/pkg/io/#ReaderFrom would probab
mithro
2016/06/14 10:57:52
I agree that interface looks like what this should
| |
118 err := aw.checkWrite() | |
119 if err != nil { | |
120 return err | |
121 } | |
122 | |
123 count, err := io.Copy(aw.w, data) | |
124 if err != nil { | |
125 log.Fatalf("error while copying (%s), archive is probably corrup ted", err) | |
126 } | |
127 aw.wroteBytes(count) | |
128 aw.checkFinished() | |
129 | |
130 return nil | |
131 } | |
132 | |
133 func (aw *Writer) WriteBytes(data []byte) error { | |
M-A Ruel
2016/06/10 17:51:11
https://golang.org/pkg/io/#ReaderFrom would probab
mithro
2016/06/14 10:57:53
io.Copy() seems to use this function under the hoo
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134 err := aw.checkWrite() | |
135 if err != nil { | |
136 return err | |
137 } | |
138 | |
139 datalen := int64(len(data)) | |
140 if datalen != aw.bytesrequired { | |
141 return fmt.Errorf("wrong amount of data, needed %d, got %d", aw. bytesrequired, datalen) | |
142 } | |
143 | |
144 aw.writePartial(data) | |
M-A Ruel
2016/06/10 17:51:11
return value is ignored
mithro
2016/06/14 10:57:53
Fixed.
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145 aw.checkFinished() | |
146 return nil | |
147 } | |
148 | |
149 func (aw *Writer) writeHeaderBytes(name string, size int64, modtime uint64, owne rid uint, groupid uint, filemod uint) error { | |
M-A Ruel
2016/06/10 17:51:11
writeHeaderInt
or something like that?
mithro
2016/06/14 10:57:52
Went with writeHeaderInternal
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150 switch aw.stage { | |
151 case WRITE_HEADER: | |
152 // Good | |
153 case WRITE_BODY: | |
154 return errors.New("usage error, already writing a file.") | |
155 case WRITE_CLOSED: | |
156 return errors.New("usage error, archive closed.") | |
157 default: | |
158 log.Fatalf("unknown writer mode: %d", aw.stage) | |
159 } | |
160 | |
161 // File name length prefixed with '#1/' (BSD variant), 16 bytes | |
162 fmt.Fprintf(aw.w, "#1/%-13d", len(name)) | |
M-A Ruel
2016/06/10 17:51:11
do not ignore the return value
mithro
2016/06/14 10:57:52
Done.
| |
163 | |
164 // Modtime, 12 bytes | |
165 fmt.Fprintf(aw.w, "%-12d", modtime) | |
166 | |
167 // Owner ID, 6 bytes | |
168 fmt.Fprintf(aw.w, "%-6d", ownerid) | |
169 | |
170 // Group ID, 6 bytes | |
171 fmt.Fprintf(aw.w, "%-6d", groupid) | |
172 | |
173 // File mode, 8 bytes | |
174 fmt.Fprintf(aw.w, "%-8o", filemod) | |
175 | |
176 // In BSD variant, file size includes the filename length | |
177 aw.bytesrequired = int64(len(name)) + size | |
178 | |
179 // File size, 10 bytes | |
180 fmt.Fprintf(aw.w, "%-10d", aw.bytesrequired) | |
181 | |
182 // File magic, 2 bytes | |
183 io.WriteString(aw.w, "\x60\n") | |
184 | |
185 aw.stage = WRITE_BODY | |
186 aw.needspadding = (aw.bytesrequired%2 != 0) | |
187 | |
188 // Filename - BSD variant | |
189 return aw.writePartial([]byte(name)) | |
190 } | |
191 | |
192 func (aw *Writer) WriteHeaderDefault(name string, size int64) error { | |
193 return aw.writeHeaderBytes(name, size, 1447140471, DEFAULT_USER, DEFAULT _GROUP, DEFAULT_MODE) | |
194 } | |
195 | |
196 func (aw *Writer) WriteHeader(stat os.FileInfo) error { | |
197 if stat.IsDir() { | |
198 return errors.New("only work with files, not directories") | |
199 } | |
200 | |
201 mode := stat.Mode() | |
202 if mode&os.ModeSymlink == os.ModeSymlink { | |
203 return errors.New("only work with files, not symlinks") | |
204 } | |
205 | |
206 /* FIXME: Should we also exclude other "special" files? | |
207 if (stat.Mode().ModeType != 0) { | |
208 return &argError{stat, "Only work with plain files."} | |
209 } | |
210 */ | |
211 | |
212 // FIXME: Where do we get user/group from - they don't appear to be in G o's Mode() object? | |
M-A Ruel
2016/06/10 17:51:11
Don't bother, I'd prefer you to not claim to suppo
mithro
2016/06/14 10:57:53
Done.
| |
213 return aw.writeHeaderBytes(stat.Name(), stat.Size(), uint64(stat.ModTime ().Unix()), DEFAULT_USER, DEFAULT_GROUP, uint(mode&os.ModePerm)) | |
214 } | |
215 | |
216 func (aw *Writer) Add(name string, data []byte) error { | |
217 err := aw.WriteHeaderDefault(name, int64(len(data))) | |
218 if err != nil { | |
219 return err | |
220 } | |
221 | |
222 return aw.WriteBytes(data) | |
223 } | |
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