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 #define CHUNKSIZE (8192)
26 static void *read_patch_file(int fd, unsigned long *sizep)
28 unsigned long size = 0, alloc = CHUNKSIZE;
29 void *buffer = xmalloc(alloc);
32 int nr = alloc - size;
35 buffer = xrealloc(buffer, alloc);
38 nr = read(fd, buffer + size, nr);
44 die("git-apply: read returned %s", strerror(errno));
52 static unsigned long linelen(char *buffer, unsigned long size)
54 unsigned long len = 0;
57 if (*buffer++ == '\n')
63 static int match_word(const char *line, const char *match)
75 /* Verify that we recognize the lines following a git header */
76 static int parse_git_header(char *line, unsigned int size)
78 unsigned long offset, len;
80 for (offset = 0 ; size > 0 ; offset += len, size -= len, line += len) {
81 len = linelen(line, size);
84 if (line[len-1] != '\n')
88 if (!memcmp(line, "@@ -", 4))
90 if (match_word(line, "new file mode"))
92 if (match_word(line, "deleted file mode"))
94 if (match_word(line, "copy"))
96 if (match_word(line, "rename"))
98 if (match_word(line, "similarity index"))
103 /* We want either a patch _or_ something real */
107 static int find_header(char *line, unsigned long size, int *hdrsize)
109 unsigned long offset, len;
111 for (offset = 0; size > 0; offset += len, size -= len, line += len) {
112 unsigned long nextlen;
114 len = linelen(line, size);
118 /* Testing this early allows us to take a few shortcuts.. */
125 * Git patch? It might not have a real patch, just a rename
126 * or mode change, so we handle that specially
128 if (!memcmp("diff --git ", line, 11)) {
129 int git_hdr_len = parse_git_header(line + len, size - len);
133 *hdrsize = len + git_hdr_len;
137 /** --- followed by +++ ? */
138 if (memcmp("--- ", line, 4) || memcmp("+++ ", line + len, 4))
142 * We only accept unified patches, so we want it to
143 * at least have "@@ -a,b +c,d @@\n", which is 14 chars
146 nextlen = linelen(line + len, size - len);
147 if (size < nextlen + 14 || memcmp("@@ -", line + len + nextlen, 4))
150 /* Ok, we'll consider it a patch */
151 *hdrsize = len + nextlen;
157 static int parse_num(const char *line, int len, int offset, const char *expect, unsigned long *p)
162 if (offset < 0 || offset >= len)
169 *p = strtoul(line, &ptr, 10);
180 if (memcmp(line, expect, ex))
187 * Parse a unified diff. Note that this really needs
188 * to parse each fragment separately, since the only
189 * way to know the difference between a "---" that is
190 * part of a patch, and a "---" that starts the next
191 * patch is to look at the line counts..
193 static int apply_fragment(char *line, unsigned long size)
195 int len = linelen(line, size), offset;
196 unsigned long oldpos, oldlines, newpos, newlines;
198 if (!len || line[len-1] != '\n')
201 /* Figure out the number of lines in a fragment */
202 offset = parse_num(line, len, 4, ",", &oldpos);
203 offset = parse_num(line, len, offset, " +", &oldlines);
204 offset = parse_num(line, len, offset, ",", &newpos);
205 offset = parse_num(line, len, offset, " @@", &newlines);
209 /* Parse the thing.. */
212 for (offset = len; size > 0; offset += len, size -= len, line += len) {
213 if (!oldlines && !newlines)
215 len = linelen(line, size);
216 if (!len || line[len-1] != '\n')
236 static int apply_single_patch(char *line, unsigned long size)
238 unsigned long offset = 0;
240 while (size > 4 && !memcmp(line, "@@ -", 4)) {
241 int len = apply_fragment(line, size);
245 printf("applying fragment:\n%.*s\n\n", len, line);
254 static int apply_chunk(char *buffer, unsigned long size)
256 int hdrsize, patchsize;
257 int offset = find_header(buffer, size, &hdrsize);
258 char *header, *patch;
262 header = buffer + offset;
264 printf("Found header:\n%.*s\n\n", hdrsize, header);
266 patch = header + hdrsize;
267 patchsize = apply_single_patch(patch, size - offset - hdrsize);
269 return offset + hdrsize + patchsize;
272 static int apply_patch(int fd)
274 unsigned long offset, size;
275 char *buffer = read_patch_file(fd, &size);
281 int nr = apply_chunk(buffer + offset, size);
291 int main(int argc, char **argv)
295 if (read_cache() < 0)
296 die("unable to read index file");
298 for (i = 1; i < argc; i++) {
299 const char *arg = argv[i];
302 if (!strcmp(arg, "-")) {
306 if (!strcmp(arg, "--no-merge")) {
310 fd = open(arg, O_RDONLY);