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525ab639 JH |
1 | /* |
2 | * Low level 3-way in-core file merge. | |
3 | * | |
4 | * Copyright (c) 2007 Junio C Hamano | |
5 | */ | |
6 | ||
7 | #include "cache.h" | |
8 | #include "attr.h" | |
9 | #include "xdiff-interface.h" | |
10 | #include "run-command.h" | |
525ab639 JH |
11 | #include "ll-merge.h" |
12 | ||
13 | struct ll_merge_driver; | |
14 | ||
15 | typedef int (*ll_merge_fn)(const struct ll_merge_driver *, | |
16 | mmbuffer_t *result, | |
17 | const char *path, | |
18 | mmfile_t *orig, | |
19 | mmfile_t *src1, const char *name1, | |
20 | mmfile_t *src2, const char *name2, | |
21 | int virtual_ancestor); | |
22 | ||
23 | struct ll_merge_driver { | |
24 | const char *name; | |
25 | const char *description; | |
26 | ll_merge_fn fn; | |
27 | const char *recursive; | |
28 | struct ll_merge_driver *next; | |
29 | char *cmdline; | |
30 | }; | |
31 | ||
32 | /* | |
33 | * Built-in low-levels | |
34 | */ | |
35 | static int ll_binary_merge(const struct ll_merge_driver *drv_unused, | |
36 | mmbuffer_t *result, | |
37 | const char *path_unused, | |
38 | mmfile_t *orig, | |
39 | mmfile_t *src1, const char *name1, | |
40 | mmfile_t *src2, const char *name2, | |
41 | int virtual_ancestor) | |
42 | { | |
43 | /* | |
44 | * The tentative merge result is "ours" for the final round, | |
45 | * or common ancestor for an internal merge. Still return | |
46 | * "conflicted merge" status. | |
47 | */ | |
48 | mmfile_t *stolen = virtual_ancestor ? orig : src1; | |
49 | ||
50 | result->ptr = stolen->ptr; | |
51 | result->size = stolen->size; | |
52 | stolen->ptr = NULL; | |
53 | return 1; | |
54 | } | |
55 | ||
56 | static int ll_xdl_merge(const struct ll_merge_driver *drv_unused, | |
57 | mmbuffer_t *result, | |
58 | const char *path_unused, | |
59 | mmfile_t *orig, | |
60 | mmfile_t *src1, const char *name1, | |
61 | mmfile_t *src2, const char *name2, | |
62 | int virtual_ancestor) | |
63 | { | |
64 | xpparam_t xpp; | |
c236bcd0 | 65 | int style = 0; |
525ab639 JH |
66 | |
67 | if (buffer_is_binary(orig->ptr, orig->size) || | |
68 | buffer_is_binary(src1->ptr, src1->size) || | |
69 | buffer_is_binary(src2->ptr, src2->size)) { | |
70 | warning("Cannot merge binary files: %s vs. %s\n", | |
71 | name1, name2); | |
72 | return ll_binary_merge(drv_unused, result, | |
73 | path_unused, | |
74 | orig, src1, name1, | |
75 | src2, name2, | |
76 | virtual_ancestor); | |
77 | } | |
78 | ||
79 | memset(&xpp, 0, sizeof(xpp)); | |
c236bcd0 JH |
80 | if (git_xmerge_style >= 0) |
81 | style = git_xmerge_style; | |
525ab639 JH |
82 | return xdl_merge(orig, |
83 | src1, name1, | |
84 | src2, name2, | |
c236bcd0 | 85 | &xpp, XDL_MERGE_ZEALOUS | style, |
525ab639 JH |
86 | result); |
87 | } | |
88 | ||
89 | static int ll_union_merge(const struct ll_merge_driver *drv_unused, | |
90 | mmbuffer_t *result, | |
91 | const char *path_unused, | |
92 | mmfile_t *orig, | |
93 | mmfile_t *src1, const char *name1, | |
94 | mmfile_t *src2, const char *name2, | |
95 | int virtual_ancestor) | |
96 | { | |
97 | char *src, *dst; | |
98 | long size; | |
99 | const int marker_size = 7; | |
c236bcd0 | 100 | int status, saved_style; |
525ab639 | 101 | |
c236bcd0 JH |
102 | /* We have to force the RCS "merge" style */ |
103 | saved_style = git_xmerge_style; | |
104 | git_xmerge_style = 0; | |
105 | status = ll_xdl_merge(drv_unused, result, path_unused, | |
106 | orig, src1, NULL, src2, NULL, | |
107 | virtual_ancestor); | |
108 | git_xmerge_style = saved_style; | |
525ab639 JH |
109 | if (status <= 0) |
110 | return status; | |
111 | size = result->size; | |
112 | src = dst = result->ptr; | |
113 | while (size) { | |
114 | char ch; | |
115 | if ((marker_size < size) && | |
116 | (*src == '<' || *src == '=' || *src == '>')) { | |
117 | int i; | |
118 | ch = *src; | |
119 | for (i = 0; i < marker_size; i++) | |
120 | if (src[i] != ch) | |
121 | goto not_a_marker; | |
122 | if (src[marker_size] != '\n') | |
123 | goto not_a_marker; | |
124 | src += marker_size + 1; | |
125 | size -= marker_size + 1; | |
126 | continue; | |
127 | } | |
128 | not_a_marker: | |
129 | do { | |
130 | ch = *src++; | |
131 | *dst++ = ch; | |
132 | size--; | |
133 | } while (ch != '\n' && size); | |
134 | } | |
135 | result->size = dst - result->ptr; | |
136 | return 0; | |
137 | } | |
138 | ||
139 | #define LL_BINARY_MERGE 0 | |
140 | #define LL_TEXT_MERGE 1 | |
141 | #define LL_UNION_MERGE 2 | |
142 | static struct ll_merge_driver ll_merge_drv[] = { | |
143 | { "binary", "built-in binary merge", ll_binary_merge }, | |
144 | { "text", "built-in 3-way text merge", ll_xdl_merge }, | |
145 | { "union", "built-in union merge", ll_union_merge }, | |
146 | }; | |
147 | ||
148 | static void create_temp(mmfile_t *src, char *path) | |
149 | { | |
150 | int fd; | |
151 | ||
152 | strcpy(path, ".merge_file_XXXXXX"); | |
153 | fd = xmkstemp(path); | |
154 | if (write_in_full(fd, src->ptr, src->size) != src->size) | |
155 | die("unable to write temp-file"); | |
156 | close(fd); | |
157 | } | |
158 | ||
159 | /* | |
160 | * User defined low-level merge driver support. | |
161 | */ | |
162 | static int ll_ext_merge(const struct ll_merge_driver *fn, | |
163 | mmbuffer_t *result, | |
164 | const char *path, | |
165 | mmfile_t *orig, | |
166 | mmfile_t *src1, const char *name1, | |
167 | mmfile_t *src2, const char *name2, | |
168 | int virtual_ancestor) | |
169 | { | |
170 | char temp[3][50]; | |
ced621b2 RS |
171 | struct strbuf cmd = STRBUF_INIT; |
172 | struct strbuf_expand_dict_entry dict[] = { | |
173 | { "O", temp[0] }, | |
174 | { "A", temp[1] }, | |
175 | { "B", temp[2] }, | |
176 | { NULL } | |
525ab639 JH |
177 | }; |
178 | struct child_process child; | |
179 | const char *args[20]; | |
180 | int status, fd, i; | |
181 | struct stat st; | |
182 | ||
183 | if (fn->cmdline == NULL) | |
184 | die("custom merge driver %s lacks command line.", fn->name); | |
185 | ||
186 | result->ptr = NULL; | |
187 | result->size = 0; | |
188 | create_temp(orig, temp[0]); | |
189 | create_temp(src1, temp[1]); | |
190 | create_temp(src2, temp[2]); | |
191 | ||
ced621b2 | 192 | strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict); |
525ab639 JH |
193 | |
194 | memset(&child, 0, sizeof(child)); | |
195 | child.argv = args; | |
196 | args[0] = "sh"; | |
197 | args[1] = "-c"; | |
ced621b2 | 198 | args[2] = cmd.buf; |
525ab639 JH |
199 | args[3] = NULL; |
200 | ||
201 | status = run_command(&child); | |
202 | if (status < -ERR_RUN_COMMAND_FORK) | |
203 | ; /* failure in run-command */ | |
204 | else | |
205 | status = -status; | |
206 | fd = open(temp[1], O_RDONLY); | |
207 | if (fd < 0) | |
208 | goto bad; | |
209 | if (fstat(fd, &st)) | |
210 | goto close_bad; | |
211 | result->size = st.st_size; | |
212 | result->ptr = xmalloc(result->size + 1); | |
213 | if (read_in_full(fd, result->ptr, result->size) != result->size) { | |
214 | free(result->ptr); | |
215 | result->ptr = NULL; | |
216 | result->size = 0; | |
217 | } | |
218 | close_bad: | |
219 | close(fd); | |
220 | bad: | |
221 | for (i = 0; i < 3; i++) | |
691f1a28 | 222 | unlink_or_warn(temp[i]); |
ced621b2 | 223 | strbuf_release(&cmd); |
525ab639 JH |
224 | return status; |
225 | } | |
226 | ||
227 | /* | |
228 | * merge.default and merge.driver configuration items | |
229 | */ | |
230 | static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail; | |
231 | static const char *default_ll_merge; | |
232 | ||
ef90d6d4 | 233 | static int read_merge_config(const char *var, const char *value, void *cb) |
525ab639 JH |
234 | { |
235 | struct ll_merge_driver *fn; | |
236 | const char *ep, *name; | |
237 | int namelen; | |
238 | ||
239 | if (!strcmp(var, "merge.default")) { | |
240 | if (value) | |
241 | default_ll_merge = strdup(value); | |
242 | return 0; | |
243 | } | |
244 | ||
245 | /* | |
246 | * We are not interested in anything but "merge.<name>.variable"; | |
247 | * especially, we do not want to look at variables such as | |
248 | * "merge.summary", "merge.tool", and "merge.verbosity". | |
249 | */ | |
250 | if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5) | |
251 | return 0; | |
252 | ||
253 | /* | |
254 | * Find existing one as we might be processing merge.<name>.var2 | |
255 | * after seeing merge.<name>.var1. | |
256 | */ | |
257 | name = var + 6; | |
258 | namelen = ep - name; | |
259 | for (fn = ll_user_merge; fn; fn = fn->next) | |
260 | if (!strncmp(fn->name, name, namelen) && !fn->name[namelen]) | |
261 | break; | |
262 | if (!fn) { | |
263 | fn = xcalloc(1, sizeof(struct ll_merge_driver)); | |
264 | fn->name = xmemdupz(name, namelen); | |
265 | fn->fn = ll_ext_merge; | |
266 | *ll_user_merge_tail = fn; | |
267 | ll_user_merge_tail = &(fn->next); | |
268 | } | |
269 | ||
270 | ep++; | |
271 | ||
272 | if (!strcmp("name", ep)) { | |
273 | if (!value) | |
274 | return error("%s: lacks value", var); | |
275 | fn->description = strdup(value); | |
276 | return 0; | |
277 | } | |
278 | ||
279 | if (!strcmp("driver", ep)) { | |
280 | if (!value) | |
281 | return error("%s: lacks value", var); | |
282 | /* | |
283 | * merge.<name>.driver specifies the command line: | |
284 | * | |
285 | * command-line | |
286 | * | |
287 | * The command-line will be interpolated with the following | |
288 | * tokens and is given to the shell: | |
289 | * | |
290 | * %O - temporary file name for the merge base. | |
291 | * %A - temporary file name for our version. | |
292 | * %B - temporary file name for the other branches' version. | |
293 | * | |
294 | * The external merge driver should write the results in the | |
295 | * file named by %A, and signal that it has done with zero exit | |
296 | * status. | |
297 | */ | |
298 | fn->cmdline = strdup(value); | |
299 | return 0; | |
300 | } | |
301 | ||
302 | if (!strcmp("recursive", ep)) { | |
303 | if (!value) | |
304 | return error("%s: lacks value", var); | |
305 | fn->recursive = strdup(value); | |
306 | return 0; | |
307 | } | |
308 | ||
309 | return 0; | |
310 | } | |
311 | ||
312 | static void initialize_ll_merge(void) | |
313 | { | |
314 | if (ll_user_merge_tail) | |
315 | return; | |
316 | ll_user_merge_tail = &ll_user_merge; | |
ef90d6d4 | 317 | git_config(read_merge_config, NULL); |
525ab639 JH |
318 | } |
319 | ||
320 | static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr) | |
321 | { | |
322 | struct ll_merge_driver *fn; | |
323 | const char *name; | |
324 | int i; | |
325 | ||
326 | initialize_ll_merge(); | |
327 | ||
328 | if (ATTR_TRUE(merge_attr)) | |
329 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
330 | else if (ATTR_FALSE(merge_attr)) | |
331 | return &ll_merge_drv[LL_BINARY_MERGE]; | |
332 | else if (ATTR_UNSET(merge_attr)) { | |
333 | if (!default_ll_merge) | |
334 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
335 | else | |
336 | name = default_ll_merge; | |
337 | } | |
338 | else | |
339 | name = merge_attr; | |
340 | ||
341 | for (fn = ll_user_merge; fn; fn = fn->next) | |
342 | if (!strcmp(fn->name, name)) | |
343 | return fn; | |
344 | ||
345 | for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++) | |
346 | if (!strcmp(ll_merge_drv[i].name, name)) | |
347 | return &ll_merge_drv[i]; | |
348 | ||
349 | /* default to the 3-way */ | |
350 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
351 | } | |
352 | ||
353 | static const char *git_path_check_merge(const char *path) | |
354 | { | |
355 | static struct git_attr_check attr_merge_check; | |
356 | ||
357 | if (!attr_merge_check.attr) | |
358 | attr_merge_check.attr = git_attr("merge", 5); | |
359 | ||
360 | if (git_checkattr(path, 1, &attr_merge_check)) | |
361 | return NULL; | |
362 | return attr_merge_check.value; | |
363 | } | |
364 | ||
365 | int ll_merge(mmbuffer_t *result_buf, | |
366 | const char *path, | |
367 | mmfile_t *ancestor, | |
368 | mmfile_t *ours, const char *our_label, | |
369 | mmfile_t *theirs, const char *their_label, | |
370 | int virtual_ancestor) | |
371 | { | |
372 | const char *ll_driver_name; | |
373 | const struct ll_merge_driver *driver; | |
374 | ||
375 | ll_driver_name = git_path_check_merge(path); | |
376 | driver = find_ll_merge_driver(ll_driver_name); | |
377 | ||
378 | if (virtual_ancestor && driver->recursive) | |
379 | driver = find_ll_merge_driver(driver->recursive); | |
380 | return driver->fn(driver, result_buf, path, | |
381 | ancestor, | |
382 | ours, our_label, | |
383 | theirs, their_label, virtual_ancestor); | |
384 | } |