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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 | /* | |
36 | * Built-in low-levels | |
37 | */ | |
38 | static int ll_binary_merge(const struct ll_merge_driver *drv_unused, | |
39 | mmbuffer_t *result, | |
40 | const char *path, | |
41 | mmfile_t *orig, const char *orig_name, | |
42 | mmfile_t *src1, const char *name1, | |
43 | mmfile_t *src2, const char *name2, | |
44 | const struct ll_merge_options *opts, | |
45 | int marker_size) | |
46 | { | |
47 | mmfile_t *stolen; | |
48 | assert(opts); | |
49 | ||
50 | /* | |
51 | * The tentative merge result is the common ancestor for an | |
52 | * internal merge. For the final merge, it is "ours" by | |
53 | * default but -Xours/-Xtheirs can tweak the choice. | |
54 | */ | |
55 | if (opts->virtual_ancestor) { | |
56 | stolen = orig; | |
57 | } else { | |
58 | switch (opts->variant) { | |
59 | default: | |
60 | warning("Cannot merge binary files: %s (%s vs. %s)", | |
61 | path, name1, name2); | |
62 | /* fallthru */ | |
63 | case XDL_MERGE_FAVOR_OURS: | |
64 | stolen = src1; | |
65 | break; | |
66 | case XDL_MERGE_FAVOR_THEIRS: | |
67 | stolen = src2; | |
68 | break; | |
69 | } | |
70 | } | |
71 | ||
72 | result->ptr = stolen->ptr; | |
73 | result->size = stolen->size; | |
74 | stolen->ptr = NULL; | |
75 | ||
76 | /* | |
77 | * With -Xtheirs or -Xours, we have cleanly merged; | |
78 | * otherwise we got a conflict. | |
79 | */ | |
80 | return (opts->variant ? 0 : 1); | |
81 | } | |
82 | ||
83 | static int ll_xdl_merge(const struct ll_merge_driver *drv_unused, | |
84 | mmbuffer_t *result, | |
85 | const char *path, | |
86 | mmfile_t *orig, const char *orig_name, | |
87 | mmfile_t *src1, const char *name1, | |
88 | mmfile_t *src2, const char *name2, | |
89 | const struct ll_merge_options *opts, | |
90 | int marker_size) | |
91 | { | |
92 | xmparam_t xmp; | |
93 | assert(opts); | |
94 | ||
95 | if (orig->size > MAX_XDIFF_SIZE || | |
96 | src1->size > MAX_XDIFF_SIZE || | |
97 | src2->size > MAX_XDIFF_SIZE || | |
98 | buffer_is_binary(orig->ptr, orig->size) || | |
99 | buffer_is_binary(src1->ptr, src1->size) || | |
100 | buffer_is_binary(src2->ptr, src2->size)) { | |
101 | return ll_binary_merge(drv_unused, result, | |
102 | path, | |
103 | orig, orig_name, | |
104 | src1, name1, | |
105 | src2, name2, | |
106 | opts, marker_size); | |
107 | } | |
108 | ||
109 | memset(&xmp, 0, sizeof(xmp)); | |
110 | xmp.level = XDL_MERGE_ZEALOUS; | |
111 | xmp.favor = opts->variant; | |
112 | xmp.xpp.flags = opts->xdl_opts; | |
113 | if (git_xmerge_style >= 0) | |
114 | xmp.style = git_xmerge_style; | |
115 | if (marker_size > 0) | |
116 | xmp.marker_size = marker_size; | |
117 | xmp.ancestor = orig_name; | |
118 | xmp.file1 = name1; | |
119 | xmp.file2 = name2; | |
120 | return xdl_merge(orig, src1, src2, &xmp, result); | |
121 | } | |
122 | ||
123 | static int ll_union_merge(const struct ll_merge_driver *drv_unused, | |
124 | mmbuffer_t *result, | |
125 | const char *path_unused, | |
126 | mmfile_t *orig, const char *orig_name, | |
127 | mmfile_t *src1, const char *name1, | |
128 | mmfile_t *src2, const char *name2, | |
129 | const struct ll_merge_options *opts, | |
130 | int marker_size) | |
131 | { | |
132 | /* Use union favor */ | |
133 | struct ll_merge_options o; | |
134 | assert(opts); | |
135 | o = *opts; | |
136 | o.variant = XDL_MERGE_FAVOR_UNION; | |
137 | return ll_xdl_merge(drv_unused, result, path_unused, | |
138 | orig, NULL, src1, NULL, src2, NULL, | |
139 | &o, marker_size); | |
140 | } | |
141 | ||
142 | #define LL_BINARY_MERGE 0 | |
143 | #define LL_TEXT_MERGE 1 | |
144 | #define LL_UNION_MERGE 2 | |
145 | static struct ll_merge_driver ll_merge_drv[] = { | |
146 | { "binary", "built-in binary merge", ll_binary_merge }, | |
147 | { "text", "built-in 3-way text merge", ll_xdl_merge }, | |
148 | { "union", "built-in union merge", ll_union_merge }, | |
149 | }; | |
150 | ||
151 | static void create_temp(mmfile_t *src, char *path, size_t len) | |
152 | { | |
153 | int fd; | |
154 | ||
155 | xsnprintf(path, len, ".merge_file_XXXXXX"); | |
156 | fd = xmkstemp(path); | |
157 | if (write_in_full(fd, src->ptr, src->size) < 0) | |
158 | die_errno("unable to write temp-file"); | |
159 | close(fd); | |
160 | } | |
161 | ||
162 | /* | |
163 | * User defined low-level merge driver support. | |
164 | */ | |
165 | static int ll_ext_merge(const struct ll_merge_driver *fn, | |
166 | mmbuffer_t *result, | |
167 | const char *path, | |
168 | mmfile_t *orig, const char *orig_name, | |
169 | mmfile_t *src1, const char *name1, | |
170 | mmfile_t *src2, const char *name2, | |
171 | const struct ll_merge_options *opts, | |
172 | int marker_size) | |
173 | { | |
174 | char temp[4][50]; | |
175 | struct strbuf cmd = STRBUF_INIT; | |
176 | struct strbuf_expand_dict_entry dict[6]; | |
177 | struct strbuf path_sq = STRBUF_INIT; | |
178 | const char *args[] = { NULL, NULL }; | |
179 | int status, fd, i; | |
180 | struct stat st; | |
181 | assert(opts); | |
182 | ||
183 | sq_quote_buf(&path_sq, path); | |
184 | dict[0].placeholder = "O"; dict[0].value = temp[0]; | |
185 | dict[1].placeholder = "A"; dict[1].value = temp[1]; | |
186 | dict[2].placeholder = "B"; dict[2].value = temp[2]; | |
187 | dict[3].placeholder = "L"; dict[3].value = temp[3]; | |
188 | dict[4].placeholder = "P"; dict[4].value = path_sq.buf; | |
189 | dict[5].placeholder = NULL; dict[5].value = NULL; | |
190 | ||
191 | if (fn->cmdline == NULL) | |
192 | die("custom merge driver %s lacks command line.", fn->name); | |
193 | ||
194 | result->ptr = NULL; | |
195 | result->size = 0; | |
196 | create_temp(orig, temp[0], sizeof(temp[0])); | |
197 | create_temp(src1, temp[1], sizeof(temp[1])); | |
198 | create_temp(src2, temp[2], sizeof(temp[2])); | |
199 | xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size); | |
200 | ||
201 | strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict); | |
202 | ||
203 | args[0] = cmd.buf; | |
204 | status = run_command_v_opt(args, RUN_USING_SHELL); | |
205 | fd = open(temp[1], O_RDONLY); | |
206 | if (fd < 0) | |
207 | goto bad; | |
208 | if (fstat(fd, &st)) | |
209 | goto close_bad; | |
210 | result->size = st.st_size; | |
211 | result->ptr = xmallocz(result->size); | |
212 | if (read_in_full(fd, result->ptr, result->size) != result->size) { | |
213 | FREE_AND_NULL(result->ptr); | |
214 | result->size = 0; | |
215 | } | |
216 | close_bad: | |
217 | close(fd); | |
218 | bad: | |
219 | for (i = 0; i < 3; i++) | |
220 | unlink_or_warn(temp[i]); | |
221 | strbuf_release(&cmd); | |
222 | strbuf_release(&path_sq); | |
223 | return status; | |
224 | } | |
225 | ||
226 | /* | |
227 | * merge.default and merge.driver configuration items | |
228 | */ | |
229 | static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail; | |
230 | static const char *default_ll_merge; | |
231 | ||
232 | static int read_merge_config(const char *var, const char *value, void *cb) | |
233 | { | |
234 | struct ll_merge_driver *fn; | |
235 | const char *key, *name; | |
236 | int namelen; | |
237 | ||
238 | if (!strcmp(var, "merge.default")) | |
239 | return git_config_string(&default_ll_merge, var, value); | |
240 | ||
241 | /* | |
242 | * We are not interested in anything but "merge.<name>.variable"; | |
243 | * especially, we do not want to look at variables such as | |
244 | * "merge.summary", "merge.tool", and "merge.verbosity". | |
245 | */ | |
246 | if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name) | |
247 | return 0; | |
248 | ||
249 | /* | |
250 | * Find existing one as we might be processing merge.<name>.var2 | |
251 | * after seeing merge.<name>.var1. | |
252 | */ | |
253 | for (fn = ll_user_merge; fn; fn = fn->next) | |
254 | if (!strncmp(fn->name, name, namelen) && !fn->name[namelen]) | |
255 | break; | |
256 | if (!fn) { | |
257 | fn = xcalloc(1, sizeof(struct ll_merge_driver)); | |
258 | fn->name = xmemdupz(name, namelen); | |
259 | fn->fn = ll_ext_merge; | |
260 | *ll_user_merge_tail = fn; | |
261 | ll_user_merge_tail = &(fn->next); | |
262 | } | |
263 | ||
264 | if (!strcmp("name", key)) | |
265 | return git_config_string(&fn->description, var, value); | |
266 | ||
267 | if (!strcmp("driver", key)) { | |
268 | if (!value) | |
269 | return error("%s: lacks value", var); | |
270 | /* | |
271 | * merge.<name>.driver specifies the command line: | |
272 | * | |
273 | * command-line | |
274 | * | |
275 | * The command-line will be interpolated with the following | |
276 | * tokens and is given to the shell: | |
277 | * | |
278 | * %O - temporary file name for the merge base. | |
279 | * %A - temporary file name for our version. | |
280 | * %B - temporary file name for the other branches' version. | |
281 | * %L - conflict marker length | |
282 | * %P - the original path (safely quoted for the shell) | |
283 | * | |
284 | * The external merge driver should write the results in the | |
285 | * file named by %A, and signal that it has done with zero exit | |
286 | * status. | |
287 | */ | |
288 | fn->cmdline = xstrdup(value); | |
289 | return 0; | |
290 | } | |
291 | ||
292 | if (!strcmp("recursive", key)) | |
293 | return git_config_string(&fn->recursive, var, value); | |
294 | ||
295 | return 0; | |
296 | } | |
297 | ||
298 | static void initialize_ll_merge(void) | |
299 | { | |
300 | if (ll_user_merge_tail) | |
301 | return; | |
302 | ll_user_merge_tail = &ll_user_merge; | |
303 | git_config(read_merge_config, NULL); | |
304 | } | |
305 | ||
306 | static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr) | |
307 | { | |
308 | struct ll_merge_driver *fn; | |
309 | const char *name; | |
310 | int i; | |
311 | ||
312 | initialize_ll_merge(); | |
313 | ||
314 | if (ATTR_TRUE(merge_attr)) | |
315 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
316 | else if (ATTR_FALSE(merge_attr)) | |
317 | return &ll_merge_drv[LL_BINARY_MERGE]; | |
318 | else if (ATTR_UNSET(merge_attr)) { | |
319 | if (!default_ll_merge) | |
320 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
321 | else | |
322 | name = default_ll_merge; | |
323 | } | |
324 | else | |
325 | name = merge_attr; | |
326 | ||
327 | for (fn = ll_user_merge; fn; fn = fn->next) | |
328 | if (!strcmp(fn->name, name)) | |
329 | return fn; | |
330 | ||
331 | for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++) | |
332 | if (!strcmp(ll_merge_drv[i].name, name)) | |
333 | return &ll_merge_drv[i]; | |
334 | ||
335 | /* default to the 3-way */ | |
336 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
337 | } | |
338 | ||
339 | static void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate) | |
340 | { | |
341 | struct strbuf strbuf = STRBUF_INIT; | |
342 | if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) { | |
343 | free(mm->ptr); | |
344 | mm->size = strbuf.len; | |
345 | mm->ptr = strbuf_detach(&strbuf, NULL); | |
346 | } | |
347 | } | |
348 | ||
349 | int ll_merge(mmbuffer_t *result_buf, | |
350 | const char *path, | |
351 | mmfile_t *ancestor, const char *ancestor_label, | |
352 | mmfile_t *ours, const char *our_label, | |
353 | mmfile_t *theirs, const char *their_label, | |
354 | struct index_state *istate, | |
355 | const struct ll_merge_options *opts) | |
356 | { | |
357 | static struct attr_check *check; | |
358 | static const struct ll_merge_options default_opts; | |
359 | const char *ll_driver_name = NULL; | |
360 | int marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
361 | const struct ll_merge_driver *driver; | |
362 | ||
363 | if (!opts) | |
364 | opts = &default_opts; | |
365 | ||
366 | if (opts->renormalize) { | |
367 | normalize_file(ancestor, path, istate); | |
368 | normalize_file(ours, path, istate); | |
369 | normalize_file(theirs, path, istate); | |
370 | } | |
371 | ||
372 | if (!check) | |
373 | check = attr_check_initl("merge", "conflict-marker-size", NULL); | |
374 | ||
375 | git_check_attr(istate, path, check); | |
376 | ll_driver_name = check->items[0].value; | |
377 | if (check->items[1].value) { | |
378 | marker_size = atoi(check->items[1].value); | |
379 | if (marker_size <= 0) | |
380 | marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
381 | } | |
382 | driver = find_ll_merge_driver(ll_driver_name); | |
383 | ||
384 | if (opts->virtual_ancestor) { | |
385 | if (driver->recursive) | |
386 | driver = find_ll_merge_driver(driver->recursive); | |
387 | } | |
388 | if (opts->extra_marker_size) { | |
389 | marker_size += opts->extra_marker_size; | |
390 | } | |
391 | return driver->fn(driver, result_buf, path, ancestor, ancestor_label, | |
392 | ours, our_label, theirs, their_label, | |
393 | opts, marker_size); | |
394 | } | |
395 | ||
396 | int ll_merge_marker_size(struct index_state *istate, const char *path) | |
397 | { | |
398 | static struct attr_check *check; | |
399 | int marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
400 | ||
401 | if (!check) | |
402 | check = attr_check_initl("conflict-marker-size", NULL); | |
403 | git_check_attr(istate, path, check); | |
404 | if (check->items[0].value) { | |
405 | marker_size = atoi(check->items[0].value); | |
406 | if (marker_size <= 0) | |
407 | marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
408 | } | |
409 | return marker_size; | |
410 | } |