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git.ipfire.org Git - thirdparty/git.git/blob - apply.c
4 * Copyright (C) Linus Torvalds, 2005
6 * This applies patches on top of some (arbitrary) version of the SCM.
8 * NOTE! It does all its work in the index file, and only cares about
9 * the files in the working directory if you tell it to "merge" the
12 * Even when merging it always takes the source from the index, and
13 * uses the working tree as a "branch" for a 3-way merge.
19 // We default to the merge behaviour, since that's what most people would
21 static int merge_patch
= 1;
22 static const char apply_usage
[] = "git-apply <patch>";
24 static int linenr
= 1;
26 #define CHUNKSIZE (8192)
28 static void *read_patch_file(int fd
, unsigned long *sizep
)
30 unsigned long size
= 0, alloc
= CHUNKSIZE
;
31 void *buffer
= xmalloc(alloc
);
34 int nr
= alloc
- size
;
37 buffer
= xrealloc(buffer
, alloc
);
40 nr
= read(fd
, buffer
+ size
, nr
);
46 die("git-apply: read returned %s", strerror(errno
));
54 static unsigned long linelen(char *buffer
, unsigned long size
)
56 unsigned long len
= 0;
59 if (*buffer
++ == '\n')
65 static int match_word(const char *line
, const char *match
)
77 /* Verify that we recognize the lines following a git header */
78 static int parse_git_header(char *line
, unsigned int size
)
80 unsigned long offset
, len
;
82 for (offset
= 0 ; size
> 0 ; offset
+= len
, size
-= len
, line
+= len
, linenr
++) {
83 len
= linelen(line
, size
);
86 if (line
[len
-1] != '\n')
90 if (!memcmp(line
, "@@ -", 4))
92 if (match_word(line
, "new file mode"))
94 if (match_word(line
, "deleted file mode"))
96 if (match_word(line
, "copy"))
98 if (match_word(line
, "rename"))
100 if (match_word(line
, "similarity index"))
105 /* We want either a patch _or_ something real */
109 static int parse_num(const char *line
, int len
, int offset
, const char *expect
, unsigned long *p
)
114 if (offset
< 0 || offset
>= len
)
121 *p
= strtoul(line
, &ptr
, 10);
132 if (memcmp(line
, expect
, ex
))
139 * Parse a unified diff fragment header of the
140 * form "@@ -a,b +c,d @@"
142 static int parse_fragment_header(char *line
, int len
, unsigned long *pos
)
146 if (!len
|| line
[len
-1] != '\n')
149 /* Figure out the number of lines in a fragment */
150 offset
= parse_num(line
, len
, 4, ",", pos
);
151 offset
= parse_num(line
, len
, offset
, " +", pos
+1);
152 offset
= parse_num(line
, len
, offset
, ",", pos
+2);
153 offset
= parse_num(line
, len
, offset
, " @@", pos
+3);
158 static int find_header(char *line
, unsigned long size
, int *hdrsize
)
160 unsigned long offset
, len
;
162 for (offset
= 0; size
> 0; offset
+= len
, size
-= len
, line
+= len
, linenr
++) {
163 unsigned long nextlen
;
165 len
= linelen(line
, size
);
169 /* Testing this early allows us to take a few shortcuts.. */
174 * Make sure we don't find any unconnected patch fragmants.
175 * That's a sign that we didn't find a header, and that a
176 * patch has become corrupted/broken up.
178 if (!memcmp("@@ -", line
, 4)) {
179 unsigned long pos
[4];
180 if (parse_fragment_header(line
, len
, pos
) < 0)
182 error("patch fragment without header at line %d: %.*s", linenr
, len
-1, line
);
189 * Git patch? It might not have a real patch, just a rename
190 * or mode change, so we handle that specially
192 if (!memcmp("diff --git ", line
, 11)) {
193 int git_hdr_len
= parse_git_header(line
+ len
, size
- len
);
197 *hdrsize
= len
+ git_hdr_len
;
201 /** --- followed by +++ ? */
202 if (memcmp("--- ", line
, 4) || memcmp("+++ ", line
+ len
, 4))
206 * We only accept unified patches, so we want it to
207 * at least have "@@ -a,b +c,d @@\n", which is 14 chars
210 nextlen
= linelen(line
+ len
, size
- len
);
211 if (size
< nextlen
+ 14 || memcmp("@@ -", line
+ len
+ nextlen
, 4))
214 /* Ok, we'll consider it a patch */
215 *hdrsize
= len
+ nextlen
;
223 * Parse a unified diff. Note that this really needs
224 * to parse each fragment separately, since the only
225 * way to know the difference between a "---" that is
226 * part of a patch, and a "---" that starts the next
227 * patch is to look at the line counts..
229 static int apply_fragment(char *line
, unsigned long size
)
231 int len
= linelen(line
, size
), offset
;
232 unsigned long pos
[4], oldlines
, newlines
;
234 offset
= parse_fragment_header(line
, len
, pos
);
240 /* Parse the thing.. */
244 for (offset
= len
; size
> 0; offset
+= len
, size
-= len
, line
+= len
, linenr
++) {
245 if (!oldlines
&& !newlines
)
247 len
= linelen(line
, size
);
248 if (!len
|| line
[len
-1] != '\n')
268 static int apply_single_patch(char *line
, unsigned long size
)
270 unsigned long offset
= 0;
272 while (size
> 4 && !memcmp(line
, "@@ -", 4)) {
273 int len
= apply_fragment(line
, size
);
275 die("corrupt patch at line %d", linenr
);
277 printf("applying fragment:\n%.*s\n\n", len
, line
);
286 static int apply_chunk(char *buffer
, unsigned long size
)
288 int hdrsize
, patchsize
;
289 int offset
= find_header(buffer
, size
, &hdrsize
);
290 char *header
, *patch
;
294 header
= buffer
+ offset
;
296 printf("Found header:\n%.*s\n\n", hdrsize
, header
);
298 patch
= header
+ hdrsize
;
299 patchsize
= apply_single_patch(patch
, size
- offset
- hdrsize
);
301 return offset
+ hdrsize
+ patchsize
;
304 static int apply_patch(int fd
)
306 unsigned long offset
, size
;
307 char *buffer
= read_patch_file(fd
, &size
);
313 int nr
= apply_chunk(buffer
+ offset
, size
);
323 int main(int argc
, char **argv
)
327 if (read_cache() < 0)
328 die("unable to read index file");
330 for (i
= 1; i
< argc
; i
++) {
331 const char *arg
= argv
[i
];
334 if (!strcmp(arg
, "-")) {
338 if (!strcmp(arg
, "--no-merge")) {
342 fd
= open(arg
, O_RDONLY
);