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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 "attr.h" | |
9 | #include "xdiff-interface.h" | |
10 | #include "run-command.h" | |
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, const char *orig_name, | |
19 | mmfile_t *src1, const char *name1, | |
20 | mmfile_t *src2, const char *name2, | |
21 | int flag, | |
22 | int marker_size); | |
23 | ||
24 | struct ll_merge_driver { | |
25 | const char *name; | |
26 | const char *description; | |
27 | ll_merge_fn fn; | |
28 | const char *recursive; | |
29 | struct ll_merge_driver *next; | |
30 | char *cmdline; | |
31 | }; | |
32 | ||
33 | /* | |
34 | * Built-in low-levels | |
35 | */ | |
36 | static int ll_binary_merge(const struct ll_merge_driver *drv_unused, | |
37 | mmbuffer_t *result, | |
38 | const char *path_unused, | |
39 | mmfile_t *orig, const char *orig_name, | |
40 | mmfile_t *src1, const char *name1, | |
41 | mmfile_t *src2, const char *name2, | |
42 | int flag, int marker_size) | |
43 | { | |
44 | /* | |
45 | * The tentative merge result is "ours" for the final round, | |
46 | * or common ancestor for an internal merge. Still return | |
47 | * "conflicted merge" status. | |
48 | */ | |
49 | mmfile_t *stolen = (flag & 01) ? orig : src1; | |
50 | ||
51 | result->ptr = stolen->ptr; | |
52 | result->size = stolen->size; | |
53 | stolen->ptr = NULL; | |
54 | return 1; | |
55 | } | |
56 | ||
57 | static int ll_xdl_merge(const struct ll_merge_driver *drv_unused, | |
58 | mmbuffer_t *result, | |
59 | const char *path, | |
60 | mmfile_t *orig, const char *orig_name, | |
61 | mmfile_t *src1, const char *name1, | |
62 | mmfile_t *src2, const char *name2, | |
63 | int flag, int marker_size) | |
64 | { | |
65 | xmparam_t xmp; | |
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 (%s vs. %s)\n", | |
71 | path, name1, name2); | |
72 | return ll_binary_merge(drv_unused, result, | |
73 | path, | |
74 | orig, orig_name, | |
75 | src1, name1, | |
76 | src2, name2, | |
77 | flag, marker_size); | |
78 | } | |
79 | ||
80 | memset(&xmp, 0, sizeof(xmp)); | |
81 | xmp.level = XDL_MERGE_ZEALOUS; | |
82 | xmp.favor= (flag >> 1) & 03; | |
83 | if (git_xmerge_style >= 0) | |
84 | xmp.style = git_xmerge_style; | |
85 | if (marker_size > 0) | |
86 | xmp.marker_size = marker_size; | |
87 | xmp.ancestor = orig_name; | |
88 | xmp.file1 = name1; | |
89 | xmp.file2 = name2; | |
90 | return xdl_merge(orig, src1, src2, &xmp, result); | |
91 | } | |
92 | ||
93 | static int ll_union_merge(const struct ll_merge_driver *drv_unused, | |
94 | mmbuffer_t *result, | |
95 | const char *path_unused, | |
96 | mmfile_t *orig, const char *orig_name, | |
97 | mmfile_t *src1, const char *name1, | |
98 | mmfile_t *src2, const char *name2, | |
99 | int flag, int marker_size) | |
100 | { | |
101 | /* Use union favor */ | |
102 | flag = (flag & 1) | (XDL_MERGE_FAVOR_UNION << 1); | |
103 | return ll_xdl_merge(drv_unused, result, path_unused, | |
104 | orig, NULL, src1, NULL, src2, NULL, | |
105 | flag, marker_size); | |
106 | return 0; | |
107 | } | |
108 | ||
109 | #define LL_BINARY_MERGE 0 | |
110 | #define LL_TEXT_MERGE 1 | |
111 | #define LL_UNION_MERGE 2 | |
112 | static struct ll_merge_driver ll_merge_drv[] = { | |
113 | { "binary", "built-in binary merge", ll_binary_merge }, | |
114 | { "text", "built-in 3-way text merge", ll_xdl_merge }, | |
115 | { "union", "built-in union merge", ll_union_merge }, | |
116 | }; | |
117 | ||
118 | static void create_temp(mmfile_t *src, char *path) | |
119 | { | |
120 | int fd; | |
121 | ||
122 | strcpy(path, ".merge_file_XXXXXX"); | |
123 | fd = xmkstemp(path); | |
124 | if (write_in_full(fd, src->ptr, src->size) != src->size) | |
125 | die_errno("unable to write temp-file"); | |
126 | close(fd); | |
127 | } | |
128 | ||
129 | /* | |
130 | * User defined low-level merge driver support. | |
131 | */ | |
132 | static int ll_ext_merge(const struct ll_merge_driver *fn, | |
133 | mmbuffer_t *result, | |
134 | const char *path, | |
135 | mmfile_t *orig, const char *orig_name, | |
136 | mmfile_t *src1, const char *name1, | |
137 | mmfile_t *src2, const char *name2, | |
138 | int flag, int marker_size) | |
139 | { | |
140 | char temp[4][50]; | |
141 | struct strbuf cmd = STRBUF_INIT; | |
142 | struct strbuf_expand_dict_entry dict[5]; | |
143 | const char *args[] = { NULL, NULL }; | |
144 | int status, fd, i; | |
145 | struct stat st; | |
146 | ||
147 | dict[0].placeholder = "O"; dict[0].value = temp[0]; | |
148 | dict[1].placeholder = "A"; dict[1].value = temp[1]; | |
149 | dict[2].placeholder = "B"; dict[2].value = temp[2]; | |
150 | dict[3].placeholder = "L"; dict[3].value = temp[3]; | |
151 | dict[4].placeholder = NULL; dict[4].value = NULL; | |
152 | ||
153 | if (fn->cmdline == NULL) | |
154 | die("custom merge driver %s lacks command line.", fn->name); | |
155 | ||
156 | result->ptr = NULL; | |
157 | result->size = 0; | |
158 | create_temp(orig, temp[0]); | |
159 | create_temp(src1, temp[1]); | |
160 | create_temp(src2, temp[2]); | |
161 | sprintf(temp[3], "%d", marker_size); | |
162 | ||
163 | strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict); | |
164 | ||
165 | args[0] = cmd.buf; | |
166 | status = run_command_v_opt(args, RUN_USING_SHELL); | |
167 | fd = open(temp[1], O_RDONLY); | |
168 | if (fd < 0) | |
169 | goto bad; | |
170 | if (fstat(fd, &st)) | |
171 | goto close_bad; | |
172 | result->size = st.st_size; | |
173 | result->ptr = xmalloc(result->size + 1); | |
174 | if (read_in_full(fd, result->ptr, result->size) != result->size) { | |
175 | free(result->ptr); | |
176 | result->ptr = NULL; | |
177 | result->size = 0; | |
178 | } | |
179 | close_bad: | |
180 | close(fd); | |
181 | bad: | |
182 | for (i = 0; i < 3; i++) | |
183 | unlink_or_warn(temp[i]); | |
184 | strbuf_release(&cmd); | |
185 | return status; | |
186 | } | |
187 | ||
188 | /* | |
189 | * merge.default and merge.driver configuration items | |
190 | */ | |
191 | static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail; | |
192 | static const char *default_ll_merge; | |
193 | ||
194 | static int read_merge_config(const char *var, const char *value, void *cb) | |
195 | { | |
196 | struct ll_merge_driver *fn; | |
197 | const char *ep, *name; | |
198 | int namelen; | |
199 | ||
200 | if (!strcmp(var, "merge.default")) { | |
201 | if (value) | |
202 | default_ll_merge = xstrdup(value); | |
203 | return 0; | |
204 | } | |
205 | ||
206 | /* | |
207 | * We are not interested in anything but "merge.<name>.variable"; | |
208 | * especially, we do not want to look at variables such as | |
209 | * "merge.summary", "merge.tool", and "merge.verbosity". | |
210 | */ | |
211 | if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5) | |
212 | return 0; | |
213 | ||
214 | /* | |
215 | * Find existing one as we might be processing merge.<name>.var2 | |
216 | * after seeing merge.<name>.var1. | |
217 | */ | |
218 | name = var + 6; | |
219 | namelen = ep - name; | |
220 | for (fn = ll_user_merge; fn; fn = fn->next) | |
221 | if (!strncmp(fn->name, name, namelen) && !fn->name[namelen]) | |
222 | break; | |
223 | if (!fn) { | |
224 | fn = xcalloc(1, sizeof(struct ll_merge_driver)); | |
225 | fn->name = xmemdupz(name, namelen); | |
226 | fn->fn = ll_ext_merge; | |
227 | *ll_user_merge_tail = fn; | |
228 | ll_user_merge_tail = &(fn->next); | |
229 | } | |
230 | ||
231 | ep++; | |
232 | ||
233 | if (!strcmp("name", ep)) { | |
234 | if (!value) | |
235 | return error("%s: lacks value", var); | |
236 | fn->description = xstrdup(value); | |
237 | return 0; | |
238 | } | |
239 | ||
240 | if (!strcmp("driver", ep)) { | |
241 | if (!value) | |
242 | return error("%s: lacks value", var); | |
243 | /* | |
244 | * merge.<name>.driver specifies the command line: | |
245 | * | |
246 | * command-line | |
247 | * | |
248 | * The command-line will be interpolated with the following | |
249 | * tokens and is given to the shell: | |
250 | * | |
251 | * %O - temporary file name for the merge base. | |
252 | * %A - temporary file name for our version. | |
253 | * %B - temporary file name for the other branches' version. | |
254 | * %L - conflict marker length | |
255 | * | |
256 | * The external merge driver should write the results in the | |
257 | * file named by %A, and signal that it has done with zero exit | |
258 | * status. | |
259 | */ | |
260 | fn->cmdline = xstrdup(value); | |
261 | return 0; | |
262 | } | |
263 | ||
264 | if (!strcmp("recursive", ep)) { | |
265 | if (!value) | |
266 | return error("%s: lacks value", var); | |
267 | fn->recursive = xstrdup(value); | |
268 | return 0; | |
269 | } | |
270 | ||
271 | return 0; | |
272 | } | |
273 | ||
274 | static void initialize_ll_merge(void) | |
275 | { | |
276 | if (ll_user_merge_tail) | |
277 | return; | |
278 | ll_user_merge_tail = &ll_user_merge; | |
279 | git_config(read_merge_config, NULL); | |
280 | } | |
281 | ||
282 | static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr) | |
283 | { | |
284 | struct ll_merge_driver *fn; | |
285 | const char *name; | |
286 | int i; | |
287 | ||
288 | initialize_ll_merge(); | |
289 | ||
290 | if (ATTR_TRUE(merge_attr)) | |
291 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
292 | else if (ATTR_FALSE(merge_attr)) | |
293 | return &ll_merge_drv[LL_BINARY_MERGE]; | |
294 | else if (ATTR_UNSET(merge_attr)) { | |
295 | if (!default_ll_merge) | |
296 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
297 | else | |
298 | name = default_ll_merge; | |
299 | } | |
300 | else | |
301 | name = merge_attr; | |
302 | ||
303 | for (fn = ll_user_merge; fn; fn = fn->next) | |
304 | if (!strcmp(fn->name, name)) | |
305 | return fn; | |
306 | ||
307 | for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++) | |
308 | if (!strcmp(ll_merge_drv[i].name, name)) | |
309 | return &ll_merge_drv[i]; | |
310 | ||
311 | /* default to the 3-way */ | |
312 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
313 | } | |
314 | ||
315 | static int git_path_check_merge(const char *path, struct git_attr_check check[2]) | |
316 | { | |
317 | if (!check[0].attr) { | |
318 | check[0].attr = git_attr("merge"); | |
319 | check[1].attr = git_attr("conflict-marker-size"); | |
320 | } | |
321 | return git_checkattr(path, 2, check); | |
322 | } | |
323 | ||
324 | int ll_merge(mmbuffer_t *result_buf, | |
325 | const char *path, | |
326 | mmfile_t *ancestor, const char *ancestor_label, | |
327 | mmfile_t *ours, const char *our_label, | |
328 | mmfile_t *theirs, const char *their_label, | |
329 | int flag) | |
330 | { | |
331 | static struct git_attr_check check[2]; | |
332 | const char *ll_driver_name = NULL; | |
333 | int marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
334 | const struct ll_merge_driver *driver; | |
335 | int virtual_ancestor = flag & 01; | |
336 | ||
337 | if (!git_path_check_merge(path, check)) { | |
338 | ll_driver_name = check[0].value; | |
339 | if (check[1].value) { | |
340 | marker_size = atoi(check[1].value); | |
341 | if (marker_size <= 0) | |
342 | marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
343 | } | |
344 | } | |
345 | driver = find_ll_merge_driver(ll_driver_name); | |
346 | if (virtual_ancestor && driver->recursive) | |
347 | driver = find_ll_merge_driver(driver->recursive); | |
348 | return driver->fn(driver, result_buf, path, ancestor, ancestor_label, | |
349 | ours, our_label, theirs, their_label, | |
350 | flag, marker_size); | |
351 | } | |
352 | ||
353 | int ll_merge_marker_size(const char *path) | |
354 | { | |
355 | static struct git_attr_check check; | |
356 | int marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
357 | ||
358 | if (!check.attr) | |
359 | check.attr = git_attr("conflict-marker-size"); | |
360 | if (!git_checkattr(path, 1, &check) && check.value) { | |
361 | marker_size = atoi(check.value); | |
362 | if (marker_size <= 0) | |
363 | marker_size = DEFAULT_CONFLICT_MARKER_SIZE; | |
364 | } | |
365 | return marker_size; | |
366 | } |