2 * Copyright (C) 2005 Junio C Hamano
11 static const char *diff_opts = "-pu";
13 static const char *external_diff(void)
15 static const char *external_diff_cmd = NULL;
16 static int done_preparing = 0;
19 return external_diff_cmd;
22 * Default values above are meant to match the
23 * Linux kernel development style. Examples of
24 * alternative styles you can specify via environment
29 if (gitenv("GIT_EXTERNAL_DIFF"))
30 external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
32 /* In case external diff fails... */
33 diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
36 return external_diff_cmd;
39 /* Help to copy the thing properly quoted for the shell safety.
40 * any single quote is replaced with '\'', and the caller is
41 * expected to enclose the result within a single quote pair.
44 * original sq_expand result
45 * name ==> name ==> 'name'
46 * a b ==> a b ==> 'a b'
47 * a'b ==> a'\''b ==> 'a'\''b'
49 static char *sq_expand(const char *src)
51 static char *buf = NULL;
56 /* count bytes needed to store the quoted string. */
57 for (cnt = 1, cp = src; *cp; cnt++, cp++)
63 while ((c = *src++)) {
67 bp = strcpy(bp, "'\\''");
75 static struct diff_tempfile {
82 static void builtin_diff(const char *name,
83 struct diff_tempfile *temp)
86 const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
87 const char *diff_arg = "'%s' '%s'||:"; /* "||:" is to return 0 */
88 const char *input_name_sq[2];
91 const char *name_sq = sq_expand(name);
94 /* diff_cmd and diff_arg have 6 %s in total which makes
95 * the sum of these strings 12 bytes larger than required.
96 * we use 2 spaces around diff-opts, and we need to count
97 * terminating NUL, so we subtract 9 here.
99 int cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
100 strlen(diff_arg) - 9);
101 for (i = 0; i < 2; i++) {
102 input_name_sq[i] = sq_expand(temp[i].name);
103 if (!strcmp(temp[i].name, "/dev/null")) {
104 path0[i] = "/dev/null";
107 path0[i] = i ? "b/" : "a/";
110 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
111 strlen(input_name_sq[i]));
114 cmd = xmalloc(cmd_size);
117 next_at += snprintf(cmd+next_at, cmd_size-next_at,
119 path0[0], path1[0], path0[1], path1[1]);
120 next_at += snprintf(cmd+next_at, cmd_size-next_at,
122 next_at += snprintf(cmd+next_at, cmd_size-next_at,
123 diff_arg, input_name_sq[0], input_name_sq[1]);
126 printf("Created: %s (mode:%s)\n", name, temp[1].mode);
127 else if (!path1[1][0])
128 printf("Deleted: %s\n", name);
129 else if (strcmp(temp[0].mode, temp[1].mode)) {
130 printf("Mode changed: %s (%s->%s)\n", name,
131 temp[0].mode, temp[1].mode);
132 /* Be careful. We do not want to diff between
133 * symlink and a file.
135 if (strncmp(temp[0].mode, "120", 3) !=
136 strncmp(temp[1].mode, "120", 3))
140 execlp("/bin/sh","sh", "-c", cmd, NULL);
144 * Given a name and sha1 pair, if the dircache tells us the file in
145 * the work tree has that object contents, return true, so that
146 * prepare_temp_file() does not have to inflate and extract.
148 static int work_tree_matches(const char *name, const unsigned char *sha1)
150 struct cache_entry *ce;
154 /* We do not read the cache ourselves here, because the
155 * benchmark with my previous version that always reads cache
156 * shows that it makes things worse for diff-tree comparing
157 * two linux-2.6 kernel trees in an already checked out work
158 * tree. This is because most diff-tree comparison deals with
159 * only a small number of files, while reading the cache is
160 * expensive for a large project, and its cost outweighs the
161 * savings we get by not inflating the object to a temporary
162 * file. Practically, this code only helps when we are used
163 * by diff-cache --cached, which does read the cache before
170 pos = cache_name_pos(name, len);
173 ce = active_cache[pos];
174 if ((lstat(name, &st) < 0) ||
175 !S_ISREG(st.st_mode) ||
176 cache_match_stat(ce, &st) ||
177 memcmp(sha1, ce->sha1, 20))
182 static void prep_temp_blob(struct diff_tempfile *temp,
190 strcpy(temp->tmp_path, ".diff_XXXXXX");
191 fd = mkstemp(temp->tmp_path);
193 die("unable to create temp-file");
194 if (write(fd, blob, size) != size)
195 die("unable to write temp-file");
197 temp->name = temp->tmp_path;
198 strcpy(temp->hex, sha1_to_hex(sha1));
200 sprintf(temp->mode, "%06o", mode);
203 static void prepare_temp_file(const char *name,
204 struct diff_tempfile *temp,
205 struct diff_spec *one)
207 static unsigned char null_sha1[20] = { 0, };
208 int use_work_tree = 0;
210 if (!one->file_valid) {
212 /* A '-' entry produces this for file-2, and
213 * a '+' entry produces this for file-1.
215 temp->name = "/dev/null";
216 strcpy(temp->hex, ".");
217 strcpy(temp->mode, ".");
221 if (one->sha1_valid &&
222 (!memcmp(one->blob_sha1, null_sha1, sizeof(null_sha1)) ||
223 work_tree_matches(name, one->blob_sha1)))
226 if (!one->sha1_valid || use_work_tree) {
229 if (lstat(temp->name, &st) < 0) {
231 goto not_a_valid_file;
232 die("stat(%s): %s", temp->name, strerror(errno));
234 if (S_ISLNK(st.st_mode)) {
236 char *buf, buf_[1024];
237 buf = ((sizeof(buf_) < st.st_size) ?
238 xmalloc(st.st_size) : buf_);
239 ret = readlink(name, buf, st.st_size);
241 die("readlink(%s)", name);
242 prep_temp_blob(temp, buf, st.st_size,
244 one->blob_sha1 : null_sha1),
246 one->mode : S_IFLNK));
249 if (!one->sha1_valid)
250 strcpy(temp->hex, sha1_to_hex(null_sha1));
252 strcpy(temp->hex, sha1_to_hex(one->blob_sha1));
253 sprintf(temp->mode, "%06o",
254 S_IFREG |ce_permissions(st.st_mode));
263 blob = read_sha1_file(one->blob_sha1, type, &size);
264 if (!blob || strcmp(type, "blob"))
265 die("unable to read blob object for %s (%s)",
266 name, sha1_to_hex(one->blob_sha1));
267 prep_temp_blob(temp, blob, size, one->blob_sha1, one->mode);
272 static void remove_tempfile(void)
276 for (i = 0; i < 2; i++)
277 if (diff_temp[i].name == diff_temp[i].tmp_path) {
278 unlink(diff_temp[i].name);
279 diff_temp[i].name = NULL;
283 static void remove_tempfile_on_signal(int signo)
288 /* An external diff command takes:
290 * diff-cmd name infile1 infile1-sha1 infile1-mode \
291 * infile2 infile2-sha1 infile2-mode.
294 void run_external_diff(const char *name,
295 struct diff_spec *one,
296 struct diff_spec *two)
298 struct diff_tempfile *temp = diff_temp;
301 static int atexit_asked = 0;
304 prepare_temp_file(name, &temp[0], one);
305 prepare_temp_file(name, &temp[1], two);
306 if (! atexit_asked &&
307 (temp[0].name == temp[0].tmp_path ||
308 temp[1].name == temp[1].tmp_path)) {
310 atexit(remove_tempfile);
312 signal(SIGINT, remove_tempfile_on_signal);
318 die("unable to fork");
320 const char *pgm = external_diff();
325 temp[0].name, temp[0].hex, temp[0].mode,
326 temp[1].name, temp[1].hex, temp[1].mode,
329 execlp(pgm, pgm, name, NULL);
332 * otherwise we use the built-in one.
335 builtin_diff(name, temp);
337 printf("* Unmerged path %s\n", name);
340 if (waitpid(pid, &status, 0) < 0 ||
341 !WIFEXITED(status) || WEXITSTATUS(status)) {
342 /* Earlier we did not check the exit status because
343 * diff exits non-zero if files are different, and
344 * we are not interested in knowing that. It was a
345 * mistake which made it harder to quit a diff-*
346 * session that uses the git-apply-patch-script as
347 * the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
348 * should also exit non-zero only when it wants to
349 * abort the entire diff-* session.
352 fprintf(stderr, "external diff died, stopping at %s.\n", name);
358 void diff_addremove(int addremove, unsigned mode,
359 const unsigned char *sha1,
360 const char *base, const char *path)
362 char concatpath[PATH_MAX];
363 struct diff_spec spec[2], *one, *two;
365 memcpy(spec[0].blob_sha1, sha1, 20);
367 spec[0].sha1_valid = spec[0].file_valid = 1;
368 spec[1].file_valid = 0;
370 if (addremove == '+') {
371 one = spec + 1; two = spec;
373 one = spec; two = one + 1;
377 strcpy(concatpath, base);
378 strcat(concatpath, path);
380 run_external_diff(path ? concatpath : base, one, two);
383 void diff_change(unsigned old_mode, unsigned new_mode,
384 const unsigned char *old_sha1,
385 const unsigned char *new_sha1,
386 const char *base, const char *path) {
387 char concatpath[PATH_MAX];
388 struct diff_spec spec[2];
390 memcpy(spec[0].blob_sha1, old_sha1, 20);
391 spec[0].mode = old_mode;
392 memcpy(spec[1].blob_sha1, new_sha1, 20);
393 spec[1].mode = new_mode;
394 spec[0].sha1_valid = spec[0].file_valid = 1;
395 spec[1].sha1_valid = spec[1].file_valid = 1;
398 strcpy(concatpath, base);
399 strcat(concatpath, path);
401 run_external_diff(path ? concatpath : base, &spec[0], &spec[1]);
404 void diff_unmerge(const char *path)
406 run_external_diff(path, NULL, NULL);