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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 "config.h" | |
9 | #include "attr.h" | |
10 | #include "xdiff-interface.h" | |
11 | #include "run-command.h" | |
12 | #include "ll-merge.h" | |
13 | #include "quote.h" | |
14 | ||
15 | struct ll_merge_driver; | |
16 | ||
17 | typedef int (*ll_merge_fn)(const struct ll_merge_driver *, | |
18 | mmbuffer_t *result, | |
19 | const char *path, | |
20 | mmfile_t *orig, const char *orig_name, | |
21 | mmfile_t *src1, const char *name1, | |
22 | mmfile_t *src2, const char *name2, | |
23 | const struct ll_merge_options *opts, | |
24 | int marker_size); | |
25 | ||
26 | struct ll_merge_driver { | |
27 | const char *name; | |
28 | const char *description; | |
29 | ll_merge_fn fn; | |
30 | const char *recursive; | |
31 | struct ll_merge_driver *next; | |
32 | char *cmdline; | |
33 | }; | |
34 | ||
35 | static struct attr_check *merge_attributes; | |
36 | static struct attr_check *load_merge_attributes(void) | |
37 | { | |
38 | if (!merge_attributes) | |
39 | merge_attributes = attr_check_initl("merge", "conflict-marker-size", NULL); | |
40 | return merge_attributes; | |
41 | } | |
42 | ||
43 | void reset_merge_attributes(void) | |
44 | { | |
45 | attr_check_free(merge_attributes); | |
46 | merge_attributes = NULL; | |
47 | } | |
48 | ||
49 | /* | |
50 | * Built-in low-levels | |
51 | */ | |
52 | static int ll_binary_merge(const struct ll_merge_driver *drv_unused, | |
53 | mmbuffer_t *result, | |
54 | const char *path, | |
55 | mmfile_t *orig, const char *orig_name, | |
56 | mmfile_t *src1, const char *name1, | |
57 | mmfile_t *src2, const char *name2, | |
58 | const struct ll_merge_options *opts, | |
59 | int marker_size) | |
60 | { | |
61 | mmfile_t *stolen; | |
62 | assert(opts); | |
63 | ||
64 | /* | |
65 | * The tentative merge result is the common ancestor for an | |
66 | * internal merge. For the final merge, it is "ours" by | |
67 | * default but -Xours/-Xtheirs can tweak the choice. | |
68 | */ | |
69 | if (opts->virtual_ancestor) { | |
70 | stolen = orig; | |
71 | } else { | |
72 | switch (opts->variant) { | |
73 | default: | |
74 | warning("Cannot merge binary files: %s (%s vs. %s)", | |
75 | path, name1, name2); | |
76 | /* fallthru */ | |
77 | case XDL_MERGE_FAVOR_OURS: | |
78 | stolen = src1; | |
79 | break; | |
80 | case XDL_MERGE_FAVOR_THEIRS: | |
81 | stolen = src2; | |
82 | break; | |
83 | } | |
84 | } | |
85 | ||
86 | result->ptr = stolen->ptr; | |
87 | result->size = stolen->size; | |
88 | stolen->ptr = NULL; | |
89 | ||
90 | /* | |
91 | * With -Xtheirs or -Xours, we have cleanly merged; | |
92 | * otherwise we got a conflict. | |
93 | */ | |
94 | return (opts->variant ? 0 : 1); | |
95 | } | |
96 | ||
97 | static int ll_xdl_merge(const struct ll_merge_driver *drv_unused, | |
98 | mmbuffer_t *result, | |
99 | const char *path, | |
100 | mmfile_t *orig, const char *orig_name, | |
101 | mmfile_t *src1, const char *name1, | |
102 | mmfile_t *src2, const char *name2, | |
103 | const struct ll_merge_options *opts, | |
104 | int marker_size) | |
105 | { | |
106 | xmparam_t xmp; | |
107 | assert(opts); | |
108 | ||
109 | if (orig->size > MAX_XDIFF_SIZE || | |
110 | src1->size > MAX_XDIFF_SIZE || | |
111 | src2->size > MAX_XDIFF_SIZE || | |
112 | buffer_is_binary(orig->ptr, orig->size) || | |
113 | buffer_is_binary(src1->ptr, src1->size) || | |
114 | buffer_is_binary(src2->ptr, src2->size)) { | |
115 | return ll_binary_merge(drv_unused, result, | |
116 | path, | |
117 | orig, orig_name, | |
118 | src1, name1, | |
119 | src2, name2, | |
120 | opts, marker_size); | |
121 | } | |
122 | ||
123 | memset(&xmp, 0, sizeof(xmp)); | |
124 | xmp.level = XDL_MERGE_ZEALOUS; | |
125 | xmp.favor = opts->variant; | |
126 | xmp.xpp.flags = opts->xdl_opts; | |
127 | if (git_xmerge_style >= 0) | |
128 | xmp.style = git_xmerge_style; | |
129 | if (marker_size > 0) | |
130 | xmp.marker_size = marker_size; | |
131 | xmp.ancestor = orig_name; | |
132 | xmp.file1 = name1; | |
133 | xmp.file2 = name2; | |
134 | return xdl_merge(orig, src1, src2, &xmp, result); | |
135 | } | |
136 | ||
137 | static int ll_union_merge(const struct ll_merge_driver *drv_unused, | |
138 | mmbuffer_t *result, | |
139 | const char *path_unused, | |
140 | mmfile_t *orig, const char *orig_name, | |
141 | mmfile_t *src1, const char *name1, | |
142 | mmfile_t *src2, const char *name2, | |
143 | const struct ll_merge_options *opts, | |
144 | int marker_size) | |
145 | { | |
146 | /* Use union favor */ | |
147 | struct ll_merge_options o; | |
148 | assert(opts); | |
149 | o = *opts; | |
150 | o.variant = XDL_MERGE_FAVOR_UNION; | |
151 | return ll_xdl_merge(drv_unused, result, path_unused, | |
152 | orig, NULL, src1, NULL, src2, NULL, | |
153 | &o, marker_size); | |
154 | } | |
155 | ||
156 | #define LL_BINARY_MERGE 0 | |
157 | #define LL_TEXT_MERGE 1 | |
158 | #define LL_UNION_MERGE 2 | |
159 | static struct ll_merge_driver ll_merge_drv[] = { | |
160 | { "binary", "built-in binary merge", ll_binary_merge }, | |
161 | { "text", "built-in 3-way text merge", ll_xdl_merge }, | |
162 | { "union", "built-in union merge", ll_union_merge }, | |
163 | }; | |
164 | ||
165 | static void create_temp(mmfile_t *src, char *path, size_t len) | |
166 | { | |
167 | int fd; | |
168 | ||
169 | xsnprintf(path, len, ".merge_file_XXXXXX"); | |
170 | fd = xmkstemp(path); | |
171 | if (write_in_full(fd, src->ptr, src->size) < 0) | |
172 | die_errno("unable to write temp-file"); | |
173 | close(fd); | |
174 | } | |
175 | ||
176 | /* | |
177 | * User defined low-level merge driver support. | |
178 | */ | |
179 | static int ll_ext_merge(const struct ll_merge_driver *fn, | |
180 | mmbuffer_t *result, | |
181 | const char *path, | |
182 | mmfile_t *orig, const char *orig_name, | |
183 | mmfile_t *src1, const char *name1, | |
184 | mmfile_t *src2, const char *name2, | |
185 | const struct ll_merge_options *opts, | |
186 | int marker_size) | |
187 | { | |
188 | char temp[4][50]; | |
189 | struct strbuf cmd = STRBUF_INIT; | |
190 | struct strbuf_expand_dict_entry dict[6]; | |
191 | struct strbuf path_sq = STRBUF_INIT; | |
192 | const char *args[] = { NULL, NULL }; | |
193 | int status, fd, i; | |
194 | struct stat st; | |
195 | assert(opts); | |
196 | ||
197 | sq_quote_buf(&path_sq, path); | |
198 | dict[0].placeholder = "O"; dict[0].value = temp[0]; | |
199 | dict[1].placeholder = "A"; dict[1].value = temp[1]; | |
200 | dict[2].placeholder = "B"; dict[2].value = temp[2]; | |
201 | dict[3].placeholder = "L"; dict[3].value = temp[3]; | |
202 | dict[4].placeholder = "P"; dict[4].value = path_sq.buf; | |
203 | dict[5].placeholder = NULL; dict[5].value = NULL; | |
204 | ||
205 | if (fn->cmdline == NULL) | |
206 | die("custom merge driver %s lacks command line.", fn->name); | |
207 | ||
208 | result->ptr = NULL; | |
209 | result->size = 0; | |
210 | create_temp(orig, temp[0], sizeof(temp[0])); | |
211 | create_temp(src1, temp[1], sizeof(temp[1])); | |
212 | create_temp(src2, temp[2], sizeof(temp[2])); | |
213 | xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size); | |
214 | ||
215 | strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict); | |
216 | ||
217 | args[0] = cmd.buf; | |
218 | status = run_command_v_opt(args, RUN_USING_SHELL); | |
219 | fd = open(temp[1], O_RDONLY); | |
220 | if (fd < 0) | |
221 | goto bad; | |
222 | if (fstat(fd, &st)) | |
223 | goto close_bad; | |
224 | result->size = st.st_size; | |
225 | result->ptr = xmallocz(result->size); | |
226 | if (read_in_full(fd, result->ptr, result->size) != result->size) { | |
227 | FREE_AND_NULL(result->ptr); | |
228 | result->size = 0; | |
229 | } | |
230 | close_bad: | |
231 | close(fd); | |
232 | bad: | |
233 | for (i = 0; i < 3; i++) | |
234 | unlink_or_warn(temp[i]); | |
235 | strbuf_release(&cmd); | |
236 | strbuf_release(&path_sq); | |
237 | return status; | |
238 | } | |
239 | ||
240 | /* | |
241 | * merge.default and merge.driver configuration items | |
242 | */ | |
243 | static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail; | |
244 | static const char *default_ll_merge; | |
245 | ||
246 | static int read_merge_config(const char *var, const char *value, void *cb) | |
247 | { | |
248 | struct ll_merge_driver *fn; | |
249 | const char *key, *name; | |
250 | int namelen; | |
251 | ||
252 | if (!strcmp(var, "merge.default")) | |
253 | return git_config_string(&default_ll_merge, var, value); | |
254 | ||
255 | /* | |
256 | * We are not interested in anything but "merge.<name>.variable"; | |
257 | * especially, we do not want to look at variables such as | |
258 | * "merge.summary", "merge.tool", and "merge.verbosity". | |
259 | */ | |
260 | if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name) | |
261 | return 0; | |
262 | ||
263 | /* | |
264 | * Find existing one as we might be processing merge.<name>.var2 | |
265 | * after seeing merge.<name>.var1. | |
266 | */ | |
267 | for (fn = ll_user_merge; fn; fn = fn->next) | |
268 | if (!strncmp(fn->name, name, namelen) && !fn->name[namelen]) | |
269 | break; | |
270 | if (!fn) { | |
271 | fn = xcalloc(1, sizeof(struct ll_merge_driver)); | |
272 | fn->name = xmemdupz(name, namelen); | |
273 | fn->fn = ll_ext_merge; | |
274 | *ll_user_merge_tail = fn; | |
275 | ll_user_merge_tail = &(fn->next); | |
276 | } | |
277 | ||
278 | if (!strcmp("name", key)) | |
279 | return git_config_string(&fn->description, var, value); | |
280 | ||
281 | if (!strcmp("driver", key)) { | |
282 | if (!value) | |
283 | return error("%s: lacks value", var); | |
284 | /* | |
285 | * merge.<name>.driver specifies the command line: | |
286 | * | |
287 | * command-line | |
288 | * | |
289 | * The command-line will be interpolated with the following | |
290 | * tokens and is given to the shell: | |
291 | * | |
292 | * %O - temporary file name for the merge base. | |
293 | * %A - temporary file name for our version. | |
294 | * %B - temporary file name for the other branches' version. | |
295 | * %L - conflict marker length | |
296 | * %P - the original path (safely quoted for the shell) | |
297 | * | |
298 | * The external merge driver should write the results in the | |
299 | * file named by %A, and signal that it has done with zero exit | |
300 | * status. | |
301 | */ | |
302 | fn->cmdline = xstrdup(value); | |
303 | return 0; | |
304 | } | |
305 | ||
306 | if (!strcmp("recursive", key)) | |
307 | return git_config_string(&fn->recursive, var, value); | |
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; | |
317 | git_config(read_merge_config, NULL); | |
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 void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate) | |
354 | { | |
355 | struct strbuf strbuf = STRBUF_INIT; | |
356 | if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) { | |
357 | free(mm->ptr); | |
358 | mm->size = strbuf.len; | |
359 | mm->ptr = strbuf_detach(&strbuf, NULL); | |
360 | } | |
361 | } | |
362 | ||
363 | int ll_merge(mmbuffer_t *result_buf, | |
364 | const char *path, | |
365 | mmfile_t *ancestor, const char *ancestor_label, | |
366 | mmfile_t *ours, const char *our_label, | |
367 | mmfile_t *theirs, const char *their_label, | |
368 | struct index_state *istate, | |
369 | const struct ll_merge_options *opts) | |
370 | { | |
371 | struct attr_check *check = load_merge_attributes(); | |
372 | static const struct ll_merge_options default_opts; | |
373 | const char *ll_driver_name = NULL; | |
374 | int marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
375 | const struct ll_merge_driver *driver; | |
376 | ||
377 | if (!opts) | |
378 | opts = &default_opts; | |
379 | ||
380 | if (opts->renormalize) { | |
381 | normalize_file(ancestor, path, istate); | |
382 | normalize_file(ours, path, istate); | |
383 | normalize_file(theirs, path, istate); | |
384 | } | |
385 | ||
386 | git_check_attr(istate, path, check); | |
387 | ll_driver_name = check->items[0].value; | |
388 | if (check->items[1].value) { | |
389 | marker_size = atoi(check->items[1].value); | |
390 | if (marker_size <= 0) | |
391 | marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
392 | } | |
393 | driver = find_ll_merge_driver(ll_driver_name); | |
394 | ||
395 | if (opts->virtual_ancestor) { | |
396 | if (driver->recursive) | |
397 | driver = find_ll_merge_driver(driver->recursive); | |
398 | } | |
399 | if (opts->extra_marker_size) { | |
400 | marker_size += opts->extra_marker_size; | |
401 | } | |
402 | return driver->fn(driver, result_buf, path, ancestor, ancestor_label, | |
403 | ours, our_label, theirs, their_label, | |
404 | opts, marker_size); | |
405 | } | |
406 | ||
407 | int ll_merge_marker_size(struct index_state *istate, const char *path) | |
408 | { | |
409 | static struct attr_check *check; | |
410 | int marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
411 | ||
412 | if (!check) | |
413 | check = attr_check_initl("conflict-marker-size", NULL); | |
414 | git_check_attr(istate, path, check); | |
415 | if (check->items[0].value) { | |
416 | marker_size = atoi(check->items[0].value); | |
417 | if (marker_size <= 0) | |
418 | marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
419 | } | |
420 | return marker_size; | |
421 | } |