5c73274b133dc03282d77ccbbd71978164a2edce
1/*
2 * Low level 3-way in-core file merge.
3 *
4 * Copyright (c) 2007 Junio C Hamano
5 */
6#include "cache.h"
8#include "attr.h"
9#include "xdiff-interface.h"
10#include "run-command.h"
11#include "ll-merge.h"
12struct ll_merge_driver;
14typedef 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 const struct ll_merge_options *opts,
22 int marker_size);
23struct 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/*
34 * Built-in low-levels
35 */
36static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
37 mmbuffer_t *result,
38 const char *path,
39 mmfile_t *orig, const char *orig_name,
40 mmfile_t *src1, const char *name1,
41 mmfile_t *src2, const char *name2,
42 const struct ll_merge_options *opts,
43 int marker_size)
44{
45 mmfile_t *stolen;
46 assert(opts);
47 /*
49 * The tentative merge result is the common ancestor for an
50 * internal merge. For the final merge, it is "ours" by
51 * default but -Xours/-Xtheirs can tweak the choice.
52 */
53 if (opts->virtual_ancestor) {
54 stolen = orig;
55 } else {
56 switch (opts->variant) {
57 default:
58 warning("Cannot merge binary files: %s (%s vs. %s)",
59 path, name1, name2);
60 /* fallthru */
61 case XDL_MERGE_FAVOR_OURS:
62 stolen = src1;
63 break;
64 case XDL_MERGE_FAVOR_THEIRS:
65 stolen = src2;
66 break;
67 }
68 }
69 result->ptr = stolen->ptr;
71 result->size = stolen->size;
72 stolen->ptr = NULL;
73 /*
75 * With -Xtheirs or -Xours, we have cleanly merged;
76 * otherwise we got a conflict.
77 */
78 return (opts->variant ? 0 : 1);
79}
80static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
82 mmbuffer_t *result,
83 const char *path,
84 mmfile_t *orig, const char *orig_name,
85 mmfile_t *src1, const char *name1,
86 mmfile_t *src2, const char *name2,
87 const struct ll_merge_options *opts,
88 int marker_size)
89{
90 xmparam_t xmp;
91 assert(opts);
92 if (buffer_is_binary(orig->ptr, orig->size) ||
94 buffer_is_binary(src1->ptr, src1->size) ||
95 buffer_is_binary(src2->ptr, src2->size)) {
96 return ll_binary_merge(drv_unused, result,
97 path,
98 orig, orig_name,
99 src1, name1,
100 src2, name2,
101 opts, marker_size);
102 }
103 memset(&xmp, 0, sizeof(xmp));
105 xmp.level = XDL_MERGE_ZEALOUS;
106 xmp.favor = opts->variant;
107 xmp.xpp.flags = opts->xdl_opts;
108 if (git_xmerge_style >= 0)
109 xmp.style = git_xmerge_style;
110 if (marker_size > 0)
111 xmp.marker_size = marker_size;
112 xmp.ancestor = orig_name;
113 xmp.file1 = name1;
114 xmp.file2 = name2;
115 return xdl_merge(orig, src1, src2, &xmp, result);
116}
117static int ll_union_merge(const struct ll_merge_driver *drv_unused,
119 mmbuffer_t *result,
120 const char *path_unused,
121 mmfile_t *orig, const char *orig_name,
122 mmfile_t *src1, const char *name1,
123 mmfile_t *src2, const char *name2,
124 const struct ll_merge_options *opts,
125 int marker_size)
126{
127 /* Use union favor */
128 struct ll_merge_options o;
129 assert(opts);
130 o = *opts;
131 o.variant = XDL_MERGE_FAVOR_UNION;
132 return ll_xdl_merge(drv_unused, result, path_unused,
133 orig, NULL, src1, NULL, src2, NULL,
134 &o, marker_size);
135}
136#define LL_BINARY_MERGE 0
138#define LL_TEXT_MERGE 1
139#define LL_UNION_MERGE 2
140static struct ll_merge_driver ll_merge_drv[] = {
141 { "binary", "built-in binary merge", ll_binary_merge },
142 { "text", "built-in 3-way text merge", ll_xdl_merge },
143 { "union", "built-in union merge", ll_union_merge },
144};
145static void create_temp(mmfile_t *src, char *path)
147{
148 int fd;
149 strcpy(path, ".merge_file_XXXXXX");
151 fd = xmkstemp(path);
152 if (write_in_full(fd, src->ptr, src->size) != src->size)
153 die_errno("unable to write temp-file");
154 close(fd);
155}
156/*
158 * User defined low-level merge driver support.
159 */
160static int ll_ext_merge(const struct ll_merge_driver *fn,
161 mmbuffer_t *result,
162 const char *path,
163 mmfile_t *orig, const char *orig_name,
164 mmfile_t *src1, const char *name1,
165 mmfile_t *src2, const char *name2,
166 const struct ll_merge_options *opts,
167 int marker_size)
168{
169 char temp[4][50];
170 struct strbuf cmd = STRBUF_INIT;
171 struct strbuf_expand_dict_entry dict[5];
172 const char *args[] = { NULL, NULL };
173 int status, fd, i;
174 struct stat st;
175 assert(opts);
176 dict[0].placeholder = "O"; dict[0].value = temp[0];
178 dict[1].placeholder = "A"; dict[1].value = temp[1];
179 dict[2].placeholder = "B"; dict[2].value = temp[2];
180 dict[3].placeholder = "L"; dict[3].value = temp[3];
181 dict[4].placeholder = NULL; dict[4].value = NULL;
182 if (fn->cmdline == NULL)
184 die("custom merge driver %s lacks command line.", fn->name);
185 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 sprintf(temp[3], "%d", marker_size);
192 strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
194 args[0] = cmd.buf;
196 status = run_command_v_opt(args, RUN_USING_SHELL);
197 fd = open(temp[1], O_RDONLY);
198 if (fd < 0)
199 goto bad;
200 if (fstat(fd, &st))
201 goto close_bad;
202 result->size = st.st_size;
203 result->ptr = xmalloc(result->size + 1);
204 if (read_in_full(fd, result->ptr, result->size) != result->size) {
205 free(result->ptr);
206 result->ptr = NULL;
207 result->size = 0;
208 }
209 close_bad:
210 close(fd);
211 bad:
212 for (i = 0; i < 3; i++)
213 unlink_or_warn(temp[i]);
214 strbuf_release(&cmd);
215 return status;
216}
217/*
219 * merge.default and merge.driver configuration items
220 */
221static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
222static const char *default_ll_merge;
223static int read_merge_config(const char *var, const char *value, void *cb)
225{
226 struct ll_merge_driver *fn;
227 const char *key, *name;
228 int namelen;
229 if (!strcmp(var, "merge.default"))
231 return git_config_string(&default_ll_merge, var, value);
232 /*
234 * We are not interested in anything but "merge.<name>.variable";
235 * especially, we do not want to look at variables such as
236 * "merge.summary", "merge.tool", and "merge.verbosity".
237 */
238 if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
239 return 0;
240 /*
242 * Find existing one as we might be processing merge.<name>.var2
243 * after seeing merge.<name>.var1.
244 */
245 for (fn = ll_user_merge; fn; fn = fn->next)
246 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
247 break;
248 if (!fn) {
249 fn = xcalloc(1, sizeof(struct ll_merge_driver));
250 fn->name = xmemdupz(name, namelen);
251 fn->fn = ll_ext_merge;
252 *ll_user_merge_tail = fn;
253 ll_user_merge_tail = &(fn->next);
254 }
255 if (!strcmp("name", key))
257 return git_config_string(&fn->description, var, value);
258 if (!strcmp("driver", key)) {
260 if (!value)
261 return error("%s: lacks value", var);
262 /*
263 * merge.<name>.driver specifies the command line:
264 *
265 * command-line
266 *
267 * The command-line will be interpolated with the following
268 * tokens and is given to the shell:
269 *
270 * %O - temporary file name for the merge base.
271 * %A - temporary file name for our version.
272 * %B - temporary file name for the other branches' version.
273 * %L - conflict marker length
274 *
275 * The external merge driver should write the results in the
276 * file named by %A, and signal that it has done with zero exit
277 * status.
278 */
279 fn->cmdline = xstrdup(value);
280 return 0;
281 }
282 if (!strcmp("recursive", key))
284 return git_config_string(&fn->recursive, var, value);
285 return 0;
287}
288static void initialize_ll_merge(void)
290{
291 if (ll_user_merge_tail)
292 return;
293 ll_user_merge_tail = &ll_user_merge;
294 git_config(read_merge_config, NULL);
295}
296static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
298{
299 struct ll_merge_driver *fn;
300 const char *name;
301 int i;
302 initialize_ll_merge();
304 if (ATTR_TRUE(merge_attr))
306 return &ll_merge_drv[LL_TEXT_MERGE];
307 else if (ATTR_FALSE(merge_attr))
308 return &ll_merge_drv[LL_BINARY_MERGE];
309 else if (ATTR_UNSET(merge_attr)) {
310 if (!default_ll_merge)
311 return &ll_merge_drv[LL_TEXT_MERGE];
312 else
313 name = default_ll_merge;
314 }
315 else
316 name = merge_attr;
317 for (fn = ll_user_merge; fn; fn = fn->next)
319 if (!strcmp(fn->name, name))
320 return fn;
321 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
323 if (!strcmp(ll_merge_drv[i].name, name))
324 return &ll_merge_drv[i];
325 /* default to the 3-way */
327 return &ll_merge_drv[LL_TEXT_MERGE];
328}
329static int git_path_check_merge(const char *path, struct git_attr_check check[2])
331{
332 if (!check[0].attr) {
333 check[0].attr = git_attr("merge");
334 check[1].attr = git_attr("conflict-marker-size");
335 }
336 return git_check_attr(path, 2, check);
337}
338static void normalize_file(mmfile_t *mm, const char *path)
340{
341 struct strbuf strbuf = STRBUF_INIT;
342 if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
343 free(mm->ptr);
344 mm->size = strbuf.len;
345 mm->ptr = strbuf_detach(&strbuf, NULL);
346 }
347}
348int 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 const struct ll_merge_options *opts)
355{
356 static struct git_attr_check check[2];
357 static const struct ll_merge_options default_opts;
358 const char *ll_driver_name = NULL;
359 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
360 const struct ll_merge_driver *driver;
361 if (!opts)
363 opts = &default_opts;
364 if (opts->renormalize) {
366 normalize_file(ancestor, path);
367 normalize_file(ours, path);
368 normalize_file(theirs, path);
369 }
370 if (!git_path_check_merge(path, check)) {
371 ll_driver_name = check[0].value;
372 if (check[1].value) {
373 marker_size = atoi(check[1].value);
374 if (marker_size <= 0)
375 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
376 }
377 }
378 driver = find_ll_merge_driver(ll_driver_name);
379 if (opts->virtual_ancestor && driver->recursive)
380 driver = find_ll_merge_driver(driver->recursive);
381 return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
382 ours, our_label, theirs, their_label,
383 opts, marker_size);
384}
385int ll_merge_marker_size(const char *path)
387{
388 static struct git_attr_check check;
389 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
390 if (!check.attr)
392 check.attr = git_attr("conflict-marker-size");
393 if (!git_check_attr(path, 1, &check) && check.value) {
394 marker_size = atoi(check.value);
395 if (marker_size <= 0)
396 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
397 }
398 return marker_size;
399}