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525ab639
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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"
b2141fc1 8#include "config.h"
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9#include "attr.h"
10#include "xdiff-interface.h"
11#include "run-command.h"
525ab639 12#include "ll-merge.h"
ef45bb1f 13#include "quote.h"
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14
15struct ll_merge_driver;
16
17typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
18 mmbuffer_t *result,
19 const char *path,
f01de62e 20 mmfile_t *orig, const char *orig_name,
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21 mmfile_t *src1, const char *name1,
22 mmfile_t *src2, const char *name2,
712516bc 23 const struct ll_merge_options *opts,
23a64c9e 24 int marker_size);
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25
26struct 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
2c65d90f 35static struct attr_check *merge_attributes;
36static 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
43void reset_merge_attributes(void)
44{
45 attr_check_free(merge_attributes);
46 merge_attributes = NULL;
47}
48
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49/*
50 * Built-in low-levels
51 */
52static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
53 mmbuffer_t *result,
e0e2065f 54 const char *path,
f01de62e 55 mmfile_t *orig, const char *orig_name,
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56 mmfile_t *src1, const char *name1,
57 mmfile_t *src2, const char *name2,
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58 const struct ll_merge_options *opts,
59 int marker_size)
525ab639 60{
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61 mmfile_t *stolen;
62 assert(opts);
63
525ab639 64 /*
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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.
525ab639 68 */
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69 if (opts->virtual_ancestor) {
70 stolen = orig;
71 } else {
72 switch (opts->variant) {
73 default:
e6d29a4b 74 warning("Cannot merge binary files: %s (%s vs. %s)",
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75 path, name1, name2);
76 /* fallthru */
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77 case XDL_MERGE_FAVOR_OURS:
78 stolen = src1;
79 break;
80 case XDL_MERGE_FAVOR_THEIRS:
81 stolen = src2;
82 break;
83 }
84 }
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85
86 result->ptr = stolen->ptr;
87 result->size = stolen->size;
88 stolen->ptr = NULL;
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89
90 /*
91 * With -Xtheirs or -Xours, we have cleanly merged;
92 * otherwise we got a conflict.
93 */
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94 return opts->variant == XDL_MERGE_FAVOR_OURS ||
95 opts->variant == XDL_MERGE_FAVOR_THEIRS ?
96 0 : 1;
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97}
98
99static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
100 mmbuffer_t *result,
606475f3 101 const char *path,
f01de62e 102 mmfile_t *orig, const char *orig_name,
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103 mmfile_t *src1, const char *name1,
104 mmfile_t *src2, const char *name2,
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105 const struct ll_merge_options *opts,
106 int marker_size)
525ab639 107{
00f8f97d 108 xmparam_t xmp;
712516bc 109 assert(opts);
525ab639 110
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111 if (orig->size > MAX_XDIFF_SIZE ||
112 src1->size > MAX_XDIFF_SIZE ||
113 src2->size > MAX_XDIFF_SIZE ||
114 buffer_is_binary(orig->ptr, orig->size) ||
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115 buffer_is_binary(src1->ptr, src1->size) ||
116 buffer_is_binary(src2->ptr, src2->size)) {
525ab639 117 return ll_binary_merge(drv_unused, result,
606475f3 118 path,
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119 orig, orig_name,
120 src1, name1,
525ab639 121 src2, name2,
712516bc 122 opts, marker_size);
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123 }
124
00f8f97d 125 memset(&xmp, 0, sizeof(xmp));
560119b9 126 xmp.level = XDL_MERGE_ZEALOUS;
712516bc 127 xmp.favor = opts->variant;
58a1ece4 128 xmp.xpp.flags = opts->xdl_opts;
c236bcd0 129 if (git_xmerge_style >= 0)
560119b9 130 xmp.style = git_xmerge_style;
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131 if (marker_size > 0)
132 xmp.marker_size = marker_size;
f01de62e 133 xmp.ancestor = orig_name;
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134 xmp.file1 = name1;
135 xmp.file2 = name2;
136 return xdl_merge(orig, src1, src2, &xmp, result);
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137}
138
139static int ll_union_merge(const struct ll_merge_driver *drv_unused,
140 mmbuffer_t *result,
382b601a 141 const char *path,
f01de62e 142 mmfile_t *orig, const char *orig_name,
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143 mmfile_t *src1, const char *name1,
144 mmfile_t *src2, const char *name2,
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145 const struct ll_merge_options *opts,
146 int marker_size)
525ab639 147{
cd1d61c4 148 /* Use union favor */
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149 struct ll_merge_options o;
150 assert(opts);
151 o = *opts;
152 o.variant = XDL_MERGE_FAVOR_UNION;
382b601a 153 return ll_xdl_merge(drv_unused, result, path,
7f53f78b 154 orig, orig_name, src1, name1, src2, name2,
712516bc 155 &o, marker_size);
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156}
157
158#define LL_BINARY_MERGE 0
159#define LL_TEXT_MERGE 1
160#define LL_UNION_MERGE 2
161static struct ll_merge_driver ll_merge_drv[] = {
162 { "binary", "built-in binary merge", ll_binary_merge },
163 { "text", "built-in 3-way text merge", ll_xdl_merge },
164 { "union", "built-in union merge", ll_union_merge },
165};
166
5096d490 167static void create_temp(mmfile_t *src, char *path, size_t len)
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168{
169 int fd;
170
5096d490 171 xsnprintf(path, len, ".merge_file_XXXXXX");
525ab639 172 fd = xmkstemp(path);
06f46f23 173 if (write_in_full(fd, src->ptr, src->size) < 0)
0721c314 174 die_errno("unable to write temp-file");
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175 close(fd);
176}
177
178/*
179 * User defined low-level merge driver support.
180 */
181static int ll_ext_merge(const struct ll_merge_driver *fn,
182 mmbuffer_t *result,
183 const char *path,
f01de62e 184 mmfile_t *orig, const char *orig_name,
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185 mmfile_t *src1, const char *name1,
186 mmfile_t *src2, const char *name2,
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187 const struct ll_merge_options *opts,
188 int marker_size)
525ab639 189{
23a64c9e 190 char temp[4][50];
ced621b2 191 struct strbuf cmd = STRBUF_INIT;
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192 struct strbuf_expand_dict_entry dict[6];
193 struct strbuf path_sq = STRBUF_INIT;
ac0ba18d 194 const char *args[] = { NULL, NULL };
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195 int status, fd, i;
196 struct stat st;
712516bc 197 assert(opts);
525ab639 198
ef45bb1f 199 sq_quote_buf(&path_sq, path);
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200 dict[0].placeholder = "O"; dict[0].value = temp[0];
201 dict[1].placeholder = "A"; dict[1].value = temp[1];
202 dict[2].placeholder = "B"; dict[2].value = temp[2];
203 dict[3].placeholder = "L"; dict[3].value = temp[3];
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204 dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
205 dict[5].placeholder = NULL; dict[5].value = NULL;
66dbfd55 206
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207 if (fn->cmdline == NULL)
208 die("custom merge driver %s lacks command line.", fn->name);
209
210 result->ptr = NULL;
211 result->size = 0;
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212 create_temp(orig, temp[0], sizeof(temp[0]));
213 create_temp(src1, temp[1], sizeof(temp[1]));
214 create_temp(src2, temp[2], sizeof(temp[2]));
215 xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
525ab639 216
ced621b2 217 strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
525ab639 218
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219 args[0] = cmd.buf;
220 status = run_command_v_opt(args, RUN_USING_SHELL);
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221 fd = open(temp[1], O_RDONLY);
222 if (fd < 0)
223 goto bad;
224 if (fstat(fd, &st))
225 goto close_bad;
226 result->size = st.st_size;
3733e694 227 result->ptr = xmallocz(result->size);
525ab639 228 if (read_in_full(fd, result->ptr, result->size) != result->size) {
e140f7af 229 FREE_AND_NULL(result->ptr);
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230 result->size = 0;
231 }
232 close_bad:
233 close(fd);
234 bad:
235 for (i = 0; i < 3; i++)
691f1a28 236 unlink_or_warn(temp[i]);
ced621b2 237 strbuf_release(&cmd);
ef45bb1f 238 strbuf_release(&path_sq);
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239 return status;
240}
241
242/*
243 * merge.default and merge.driver configuration items
244 */
245static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
246static const char *default_ll_merge;
247
ef90d6d4 248static int read_merge_config(const char *var, const char *value, void *cb)
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249{
250 struct ll_merge_driver *fn;
d731f0ad 251 const char *key, *name;
f5914f4b 252 size_t namelen;
525ab639 253
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TA
254 if (!strcmp(var, "merge.default"))
255 return git_config_string(&default_ll_merge, var, value);
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256
257 /*
258 * We are not interested in anything but "merge.<name>.variable";
259 * especially, we do not want to look at variables such as
260 * "merge.summary", "merge.tool", and "merge.verbosity".
261 */
d731f0ad 262 if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
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263 return 0;
264
265 /*
266 * Find existing one as we might be processing merge.<name>.var2
267 * after seeing merge.<name>.var1.
268 */
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269 for (fn = ll_user_merge; fn; fn = fn->next)
270 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
271 break;
272 if (!fn) {
ca56dadb 273 CALLOC_ARRAY(fn, 1);
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274 fn->name = xmemdupz(name, namelen);
275 fn->fn = ll_ext_merge;
276 *ll_user_merge_tail = fn;
277 ll_user_merge_tail = &(fn->next);
278 }
279
6ea358f7
TA
280 if (!strcmp("name", key))
281 return git_config_string(&fn->description, var, value);
525ab639 282
d731f0ad 283 if (!strcmp("driver", key)) {
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284 if (!value)
285 return error("%s: lacks value", var);
286 /*
287 * merge.<name>.driver specifies the command line:
288 *
289 * command-line
290 *
291 * The command-line will be interpolated with the following
292 * tokens and is given to the shell:
293 *
294 * %O - temporary file name for the merge base.
295 * %A - temporary file name for our version.
296 * %B - temporary file name for the other branches' version.
23a64c9e 297 * %L - conflict marker length
ef45bb1f 298 * %P - the original path (safely quoted for the shell)
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299 *
300 * The external merge driver should write the results in the
301 * file named by %A, and signal that it has done with zero exit
302 * status.
303 */
90dce515 304 fn->cmdline = xstrdup(value);
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305 return 0;
306 }
307
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TA
308 if (!strcmp("recursive", key))
309 return git_config_string(&fn->recursive, var, value);
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310
311 return 0;
312}
313
314static void initialize_ll_merge(void)
315{
316 if (ll_user_merge_tail)
317 return;
318 ll_user_merge_tail = &ll_user_merge;
ef90d6d4 319 git_config(read_merge_config, NULL);
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320}
321
322static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
323{
324 struct ll_merge_driver *fn;
325 const char *name;
326 int i;
327
328 initialize_ll_merge();
329
330 if (ATTR_TRUE(merge_attr))
331 return &ll_merge_drv[LL_TEXT_MERGE];
332 else if (ATTR_FALSE(merge_attr))
333 return &ll_merge_drv[LL_BINARY_MERGE];
334 else if (ATTR_UNSET(merge_attr)) {
335 if (!default_ll_merge)
336 return &ll_merge_drv[LL_TEXT_MERGE];
337 else
338 name = default_ll_merge;
339 }
340 else
341 name = merge_attr;
342
343 for (fn = ll_user_merge; fn; fn = fn->next)
344 if (!strcmp(fn->name, name))
345 return fn;
346
347 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
348 if (!strcmp(ll_merge_drv[i].name, name))
349 return &ll_merge_drv[i];
350
351 /* default to the 3-way */
352 return &ll_merge_drv[LL_TEXT_MERGE];
353}
354
32eaa468 355static void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate)
f217f0e8
EB
356{
357 struct strbuf strbuf = STRBUF_INIT;
32eaa468 358 if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
f217f0e8
EB
359 free(mm->ptr);
360 mm->size = strbuf.len;
361 mm->ptr = strbuf_detach(&strbuf, NULL);
362 }
363}
364
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365int ll_merge(mmbuffer_t *result_buf,
366 const char *path,
f01de62e 367 mmfile_t *ancestor, const char *ancestor_label,
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368 mmfile_t *ours, const char *our_label,
369 mmfile_t *theirs, const char *their_label,
32eaa468 370 struct index_state *istate,
712516bc 371 const struct ll_merge_options *opts)
525ab639 372{
2c65d90f 373 struct attr_check *check = load_merge_attributes();
4fb40c2b 374 static const struct ll_merge_options default_opts;
23a64c9e
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375 const char *ll_driver_name = NULL;
376 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
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377 const struct ll_merge_driver *driver;
378
4fb40c2b
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379 if (!opts)
380 opts = &default_opts;
712516bc
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381
382 if (opts->renormalize) {
32eaa468
NTND
383 normalize_file(ancestor, path, istate);
384 normalize_file(ours, path, istate);
385 normalize_file(theirs, path, istate);
f217f0e8 386 }
2aef63d3 387
11877b9e 388 git_check_attr(istate, path, check);
d64324cb
TB
389 ll_driver_name = check->items[0].value;
390 if (check->items[1].value) {
391 marker_size = atoi(check->items[1].value);
392 if (marker_size <= 0)
393 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
23a64c9e 394 }
525ab639 395 driver = find_ll_merge_driver(ll_driver_name);
d694a179
JH
396
397 if (opts->virtual_ancestor) {
398 if (driver->recursive)
399 driver = find_ll_merge_driver(driver->recursive);
b2a7942b
EN
400 }
401 if (opts->extra_marker_size) {
402 marker_size += opts->extra_marker_size;
d694a179 403 }
f01de62e 404 return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
23a64c9e 405 ours, our_label, theirs, their_label,
712516bc 406 opts, marker_size);
525ab639 407}
8588567c 408
32eaa468 409int ll_merge_marker_size(struct index_state *istate, const char *path)
8588567c 410{
2aef63d3 411 static struct attr_check *check;
8588567c
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412 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
413
2aef63d3
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414 if (!check)
415 check = attr_check_initl("conflict-marker-size", NULL);
11877b9e 416 git_check_attr(istate, path, check);
d64324cb 417 if (check->items[0].value) {
2aef63d3 418 marker_size = atoi(check->items[0].value);
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JH
419 if (marker_size <= 0)
420 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
421 }
422 return marker_size;
525ab639 423}