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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" | |
11 | #include "interpolate.h" | |
12 | #include "ll-merge.h" | |
13 | ||
14 | struct ll_merge_driver; | |
15 | ||
16 | typedef int (*ll_merge_fn)(const struct ll_merge_driver *, | |
17 | mmbuffer_t *result, | |
18 | const char *path, | |
19 | mmfile_t *orig, | |
20 | mmfile_t *src1, const char *name1, | |
21 | mmfile_t *src2, const char *name2, | |
22 | int virtual_ancestor); | |
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, | |
40 | mmfile_t *src1, const char *name1, | |
41 | mmfile_t *src2, const char *name2, | |
42 | int virtual_ancestor) | |
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 = virtual_ancestor ? 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_unused, | |
60 | mmfile_t *orig, | |
61 | mmfile_t *src1, const char *name1, | |
62 | mmfile_t *src2, const char *name2, | |
63 | int virtual_ancestor) | |
64 | { | |
65 | xpparam_t xpp; | |
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)); | |
80 | return xdl_merge(orig, | |
81 | src1, name1, | |
82 | src2, name2, | |
83 | &xpp, XDL_MERGE_ZEALOUS, | |
84 | result); | |
85 | } | |
86 | ||
87 | static int ll_union_merge(const struct ll_merge_driver *drv_unused, | |
88 | mmbuffer_t *result, | |
89 | const char *path_unused, | |
90 | mmfile_t *orig, | |
91 | mmfile_t *src1, const char *name1, | |
92 | mmfile_t *src2, const char *name2, | |
93 | int virtual_ancestor) | |
94 | { | |
95 | char *src, *dst; | |
96 | long size; | |
97 | const int marker_size = 7; | |
98 | ||
99 | int status = ll_xdl_merge(drv_unused, result, path_unused, | |
100 | orig, src1, NULL, src2, NULL, | |
101 | virtual_ancestor); | |
102 | if (status <= 0) | |
103 | return status; | |
104 | size = result->size; | |
105 | src = dst = result->ptr; | |
106 | while (size) { | |
107 | char ch; | |
108 | if ((marker_size < size) && | |
109 | (*src == '<' || *src == '=' || *src == '>')) { | |
110 | int i; | |
111 | ch = *src; | |
112 | for (i = 0; i < marker_size; i++) | |
113 | if (src[i] != ch) | |
114 | goto not_a_marker; | |
115 | if (src[marker_size] != '\n') | |
116 | goto not_a_marker; | |
117 | src += marker_size + 1; | |
118 | size -= marker_size + 1; | |
119 | continue; | |
120 | } | |
121 | not_a_marker: | |
122 | do { | |
123 | ch = *src++; | |
124 | *dst++ = ch; | |
125 | size--; | |
126 | } while (ch != '\n' && size); | |
127 | } | |
128 | result->size = dst - result->ptr; | |
129 | return 0; | |
130 | } | |
131 | ||
132 | #define LL_BINARY_MERGE 0 | |
133 | #define LL_TEXT_MERGE 1 | |
134 | #define LL_UNION_MERGE 2 | |
135 | static struct ll_merge_driver ll_merge_drv[] = { | |
136 | { "binary", "built-in binary merge", ll_binary_merge }, | |
137 | { "text", "built-in 3-way text merge", ll_xdl_merge }, | |
138 | { "union", "built-in union merge", ll_union_merge }, | |
139 | }; | |
140 | ||
141 | static void create_temp(mmfile_t *src, char *path) | |
142 | { | |
143 | int fd; | |
144 | ||
145 | strcpy(path, ".merge_file_XXXXXX"); | |
146 | fd = xmkstemp(path); | |
147 | if (write_in_full(fd, src->ptr, src->size) != src->size) | |
148 | die("unable to write temp-file"); | |
149 | close(fd); | |
150 | } | |
151 | ||
152 | /* | |
153 | * User defined low-level merge driver support. | |
154 | */ | |
155 | static int ll_ext_merge(const struct ll_merge_driver *fn, | |
156 | mmbuffer_t *result, | |
157 | const char *path, | |
158 | mmfile_t *orig, | |
159 | mmfile_t *src1, const char *name1, | |
160 | mmfile_t *src2, const char *name2, | |
161 | int virtual_ancestor) | |
162 | { | |
163 | char temp[3][50]; | |
164 | char cmdbuf[2048]; | |
165 | struct interp table[] = { | |
166 | { "%O" }, | |
167 | { "%A" }, | |
168 | { "%B" }, | |
169 | }; | |
170 | struct child_process child; | |
171 | const char *args[20]; | |
172 | int status, fd, i; | |
173 | struct stat st; | |
174 | ||
175 | if (fn->cmdline == NULL) | |
176 | die("custom merge driver %s lacks command line.", fn->name); | |
177 | ||
178 | result->ptr = NULL; | |
179 | result->size = 0; | |
180 | create_temp(orig, temp[0]); | |
181 | create_temp(src1, temp[1]); | |
182 | create_temp(src2, temp[2]); | |
183 | ||
184 | interp_set_entry(table, 0, temp[0]); | |
185 | interp_set_entry(table, 1, temp[1]); | |
186 | interp_set_entry(table, 2, temp[2]); | |
187 | ||
188 | interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3); | |
189 | ||
190 | memset(&child, 0, sizeof(child)); | |
191 | child.argv = args; | |
192 | args[0] = "sh"; | |
193 | args[1] = "-c"; | |
194 | args[2] = cmdbuf; | |
195 | args[3] = NULL; | |
196 | ||
197 | status = run_command(&child); | |
198 | if (status < -ERR_RUN_COMMAND_FORK) | |
199 | ; /* failure in run-command */ | |
200 | else | |
201 | status = -status; | |
202 | fd = open(temp[1], O_RDONLY); | |
203 | if (fd < 0) | |
204 | goto bad; | |
205 | if (fstat(fd, &st)) | |
206 | goto close_bad; | |
207 | result->size = st.st_size; | |
208 | result->ptr = xmalloc(result->size + 1); | |
209 | if (read_in_full(fd, result->ptr, result->size) != result->size) { | |
210 | free(result->ptr); | |
211 | result->ptr = NULL; | |
212 | result->size = 0; | |
213 | } | |
214 | close_bad: | |
215 | close(fd); | |
216 | bad: | |
217 | for (i = 0; i < 3; i++) | |
218 | unlink(temp[i]); | |
219 | return status; | |
220 | } | |
221 | ||
222 | /* | |
223 | * merge.default and merge.driver configuration items | |
224 | */ | |
225 | static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail; | |
226 | static const char *default_ll_merge; | |
227 | ||
ef90d6d4 | 228 | static int read_merge_config(const char *var, const char *value, void *cb) |
525ab639 JH |
229 | { |
230 | struct ll_merge_driver *fn; | |
231 | const char *ep, *name; | |
232 | int namelen; | |
233 | ||
234 | if (!strcmp(var, "merge.default")) { | |
235 | if (value) | |
236 | default_ll_merge = strdup(value); | |
237 | return 0; | |
238 | } | |
239 | ||
240 | /* | |
241 | * We are not interested in anything but "merge.<name>.variable"; | |
242 | * especially, we do not want to look at variables such as | |
243 | * "merge.summary", "merge.tool", and "merge.verbosity". | |
244 | */ | |
245 | if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5) | |
246 | return 0; | |
247 | ||
248 | /* | |
249 | * Find existing one as we might be processing merge.<name>.var2 | |
250 | * after seeing merge.<name>.var1. | |
251 | */ | |
252 | name = var + 6; | |
253 | namelen = ep - name; | |
254 | for (fn = ll_user_merge; fn; fn = fn->next) | |
255 | if (!strncmp(fn->name, name, namelen) && !fn->name[namelen]) | |
256 | break; | |
257 | if (!fn) { | |
258 | fn = xcalloc(1, sizeof(struct ll_merge_driver)); | |
259 | fn->name = xmemdupz(name, namelen); | |
260 | fn->fn = ll_ext_merge; | |
261 | *ll_user_merge_tail = fn; | |
262 | ll_user_merge_tail = &(fn->next); | |
263 | } | |
264 | ||
265 | ep++; | |
266 | ||
267 | if (!strcmp("name", ep)) { | |
268 | if (!value) | |
269 | return error("%s: lacks value", var); | |
270 | fn->description = strdup(value); | |
271 | return 0; | |
272 | } | |
273 | ||
274 | if (!strcmp("driver", ep)) { | |
275 | if (!value) | |
276 | return error("%s: lacks value", var); | |
277 | /* | |
278 | * merge.<name>.driver specifies the command line: | |
279 | * | |
280 | * command-line | |
281 | * | |
282 | * The command-line will be interpolated with the following | |
283 | * tokens and is given to the shell: | |
284 | * | |
285 | * %O - temporary file name for the merge base. | |
286 | * %A - temporary file name for our version. | |
287 | * %B - temporary file name for the other branches' version. | |
288 | * | |
289 | * The external merge driver should write the results in the | |
290 | * file named by %A, and signal that it has done with zero exit | |
291 | * status. | |
292 | */ | |
293 | fn->cmdline = strdup(value); | |
294 | return 0; | |
295 | } | |
296 | ||
297 | if (!strcmp("recursive", ep)) { | |
298 | if (!value) | |
299 | return error("%s: lacks value", var); | |
300 | fn->recursive = strdup(value); | |
301 | return 0; | |
302 | } | |
303 | ||
304 | return 0; | |
305 | } | |
306 | ||
307 | static void initialize_ll_merge(void) | |
308 | { | |
309 | if (ll_user_merge_tail) | |
310 | return; | |
311 | ll_user_merge_tail = &ll_user_merge; | |
ef90d6d4 | 312 | git_config(read_merge_config, NULL); |
525ab639 JH |
313 | } |
314 | ||
315 | static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr) | |
316 | { | |
317 | struct ll_merge_driver *fn; | |
318 | const char *name; | |
319 | int i; | |
320 | ||
321 | initialize_ll_merge(); | |
322 | ||
323 | if (ATTR_TRUE(merge_attr)) | |
324 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
325 | else if (ATTR_FALSE(merge_attr)) | |
326 | return &ll_merge_drv[LL_BINARY_MERGE]; | |
327 | else if (ATTR_UNSET(merge_attr)) { | |
328 | if (!default_ll_merge) | |
329 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
330 | else | |
331 | name = default_ll_merge; | |
332 | } | |
333 | else | |
334 | name = merge_attr; | |
335 | ||
336 | for (fn = ll_user_merge; fn; fn = fn->next) | |
337 | if (!strcmp(fn->name, name)) | |
338 | return fn; | |
339 | ||
340 | for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++) | |
341 | if (!strcmp(ll_merge_drv[i].name, name)) | |
342 | return &ll_merge_drv[i]; | |
343 | ||
344 | /* default to the 3-way */ | |
345 | return &ll_merge_drv[LL_TEXT_MERGE]; | |
346 | } | |
347 | ||
348 | static const char *git_path_check_merge(const char *path) | |
349 | { | |
350 | static struct git_attr_check attr_merge_check; | |
351 | ||
352 | if (!attr_merge_check.attr) | |
353 | attr_merge_check.attr = git_attr("merge", 5); | |
354 | ||
355 | if (git_checkattr(path, 1, &attr_merge_check)) | |
356 | return NULL; | |
357 | return attr_merge_check.value; | |
358 | } | |
359 | ||
360 | int ll_merge(mmbuffer_t *result_buf, | |
361 | const char *path, | |
362 | mmfile_t *ancestor, | |
363 | mmfile_t *ours, const char *our_label, | |
364 | mmfile_t *theirs, const char *their_label, | |
365 | int virtual_ancestor) | |
366 | { | |
367 | const char *ll_driver_name; | |
368 | const struct ll_merge_driver *driver; | |
369 | ||
370 | ll_driver_name = git_path_check_merge(path); | |
371 | driver = find_ll_merge_driver(ll_driver_name); | |
372 | ||
373 | if (virtual_ancestor && driver->recursive) | |
374 | driver = find_ll_merge_driver(driver->recursive); | |
375 | return driver->fn(driver, result_buf, path, | |
376 | ancestor, | |
377 | ours, our_label, | |
378 | theirs, their_label, virtual_ancestor); | |
379 | } |