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"
12#include "quote.h"
13struct ll_merge_driver;
15typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
17 mmbuffer_t *result,
18 const char *path,
19 mmfile_t *orig, const char *orig_name,
20 mmfile_t *src1, const char *name1,
21 mmfile_t *src2, const char *name2,
22 const struct ll_merge_options *opts,
23 int marker_size);
24struct ll_merge_driver {
26 const char *name;
27 const char *description;
28 ll_merge_fn fn;
29 const char *recursive;
30 struct ll_merge_driver *next;
31 char *cmdline;
32};
33/*
35 * Built-in low-levels
36 */
37static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
38 mmbuffer_t *result,
39 const char *path,
40 mmfile_t *orig, const char *orig_name,
41 mmfile_t *src1, const char *name1,
42 mmfile_t *src2, const char *name2,
43 const struct ll_merge_options *opts,
44 int marker_size)
45{
46 mmfile_t *stolen;
47 assert(opts);
48 /*
50 * The tentative merge result is the or common ancestor for an internal merge.
51 */
52 if (opts->virtual_ancestor) {
53 stolen = orig;
54 } else {
55 switch (opts->variant) {
56 default:
57 warning("Cannot merge binary files: %s (%s vs. %s)",
58 path, name1, name2);
59 /* fallthru */
60 case XDL_MERGE_FAVOR_OURS:
61 stolen = src1;
62 break;
63 case XDL_MERGE_FAVOR_THEIRS:
64 stolen = src2;
65 break;
66 }
67 }
68 result->ptr = stolen->ptr;
70 result->size = stolen->size;
71 stolen->ptr = NULL;
72 /*
74 * With -Xtheirs or -Xours, we have cleanly merged;
75 * otherwise we got a conflict.
76 */
77 return (opts->variant ? 0 : 1);
78}
79static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
81 mmbuffer_t *result,
82 const char *path,
83 mmfile_t *orig, const char *orig_name,
84 mmfile_t *src1, const char *name1,
85 mmfile_t *src2, const char *name2,
86 const struct ll_merge_options *opts,
87 int marker_size)
88{
89 xmparam_t xmp;
90 assert(opts);
91 if (orig->size > MAX_XDIFF_SIZE ||
93 src1->size > MAX_XDIFF_SIZE ||
94 src2->size > MAX_XDIFF_SIZE ||
95 buffer_is_binary(orig->ptr, orig->size) ||
96 buffer_is_binary(src1->ptr, src1->size) ||
97 buffer_is_binary(src2->ptr, src2->size)) {
98 return ll_binary_merge(drv_unused, result,
99 path,
100 orig, orig_name,
101 src1, name1,
102 src2, name2,
103 opts, marker_size);
104 }
105 memset(&xmp, 0, sizeof(xmp));
107 xmp.level = XDL_MERGE_ZEALOUS;
108 xmp.favor = opts->variant;
109 xmp.xpp.flags = opts->xdl_opts;
110 if (git_xmerge_style >= 0)
111 xmp.style = git_xmerge_style;
112 if (marker_size > 0)
113 xmp.marker_size = marker_size;
114 xmp.ancestor = orig_name;
115 xmp.file1 = name1;
116 xmp.file2 = name2;
117 return xdl_merge(orig, src1, src2, &xmp, result);
118}
119static int ll_union_merge(const struct ll_merge_driver *drv_unused,
121 mmbuffer_t *result,
122 const char *path_unused,
123 mmfile_t *orig, const char *orig_name,
124 mmfile_t *src1, const char *name1,
125 mmfile_t *src2, const char *name2,
126 const struct ll_merge_options *opts,
127 int marker_size)
128{
129 /* Use union favor */
130 struct ll_merge_options o;
131 assert(opts);
132 o = *opts;
133 o.variant = XDL_MERGE_FAVOR_UNION;
134 return ll_xdl_merge(drv_unused, result, path_unused,
135 orig, NULL, src1, NULL, src2, NULL,
136 &o, marker_size);
137}
138#define LL_BINARY_MERGE 0
140#define LL_TEXT_MERGE 1
141#define LL_UNION_MERGE 2
142static struct ll_merge_driver ll_merge_drv[] = {
143 { "binary", "built-in binary merge", ll_binary_merge },
144 { "text", "built-in 3-way text merge", ll_xdl_merge },
145 { "union", "built-in union merge", ll_union_merge },
146};
147static void create_temp(mmfile_t *src, char *path, size_t len)
149{
150 int fd;
151 xsnprintf(path, len, ".merge_file_XXXXXX");
153 fd = xmkstemp(path);
154 if (write_in_full(fd, src->ptr, src->size) != src->size)
155 die_errno("unable to write temp-file");
156 close(fd);
157}
158/*
160 * User defined low-level merge driver support.
161 */
162static int ll_ext_merge(const struct ll_merge_driver *fn,
163 mmbuffer_t *result,
164 const char *path,
165 mmfile_t *orig, const char *orig_name,
166 mmfile_t *src1, const char *name1,
167 mmfile_t *src2, const char *name2,
168 const struct ll_merge_options *opts,
169 int marker_size)
170{
171 char temp[4][50];
172 struct strbuf cmd = STRBUF_INIT;
173 struct strbuf_expand_dict_entry dict[6];
174 struct strbuf path_sq = STRBUF_INIT;
175 const char *args[] = { NULL, NULL };
176 int status, fd, i;
177 struct stat st;
178 assert(opts);
179 sq_quote_buf(&path_sq, path);
181 dict[0].placeholder = "O"; dict[0].value = temp[0];
182 dict[1].placeholder = "A"; dict[1].value = temp[1];
183 dict[2].placeholder = "B"; dict[2].value = temp[2];
184 dict[3].placeholder = "L"; dict[3].value = temp[3];
185 dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
186 dict[5].placeholder = NULL; dict[5].value = NULL;
187 if (fn->cmdline == NULL)
189 die("custom merge driver %s lacks command line.", fn->name);
190 result->ptr = NULL;
192 result->size = 0;
193 create_temp(orig, temp[0], sizeof(temp[0]));
194 create_temp(src1, temp[1], sizeof(temp[1]));
195 create_temp(src2, temp[2], sizeof(temp[2]));
196 xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
197 strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
199 args[0] = cmd.buf;
201 status = run_command_v_opt(args, RUN_USING_SHELL);
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_or_warn(temp[i]);
219 strbuf_release(&cmd);
220 strbuf_release(&path_sq);
221 return status;
222}
223/*
225 * merge.default and merge.driver configuration items
226 */
227static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
228static const char *default_ll_merge;
229static int read_merge_config(const char *var, const char *value, void *cb)
231{
232 struct ll_merge_driver *fn;
233 const char *key, *name;
234 int namelen;
235 if (!strcmp(var, "merge.default"))
237 return git_config_string(&default_ll_merge, var, value);
238 /*
240 * We are not interested in anything but "merge.<name>.variable";
241 * especially, we do not want to look at variables such as
242 * "merge.summary", "merge.tool", and "merge.verbosity".
243 */
244 if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
245 return 0;
246 /*
248 * Find existing one as we might be processing merge.<name>.var2
249 * after seeing merge.<name>.var1.
250 */
251 for (fn = ll_user_merge; fn; fn = fn->next)
252 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
253 break;
254 if (!fn) {
255 fn = xcalloc(1, sizeof(struct ll_merge_driver));
256 fn->name = xmemdupz(name, namelen);
257 fn->fn = ll_ext_merge;
258 *ll_user_merge_tail = fn;
259 ll_user_merge_tail = &(fn->next);
260 }
261 if (!strcmp("name", key))
263 return git_config_string(&fn->description, var, value);
264 if (!strcmp("driver", key)) {
266 if (!value)
267 return error("%s: lacks value", var);
268 /*
269 * merge.<name>.driver specifies the command line:
270 *
271 * command-line
272 *
273 * The command-line will be interpolated with the following
274 * tokens and is given to the shell:
275 *
276 * %O - temporary file name for the merge base.
277 * %A - temporary file name for our version.
278 * %B - temporary file name for the other branches' version.
279 * %L - conflict marker length
280 * %P - the original path (safely quoted for the shell)
281 *
282 * The external merge driver should write the results in the
283 * file named by %A, and signal that it has done with zero exit
284 * status.
285 */
286 fn->cmdline = xstrdup(value);
287 return 0;
288 }
289 if (!strcmp("recursive", key))
291 return git_config_string(&fn->recursive, var, value);
292 return 0;
294}
295static void initialize_ll_merge(void)
297{
298 if (ll_user_merge_tail)
299 return;
300 ll_user_merge_tail = &ll_user_merge;
301 git_config(read_merge_config, NULL);
302}
303static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
305{
306 struct ll_merge_driver *fn;
307 const char *name;
308 int i;
309 initialize_ll_merge();
311 if (ATTR_TRUE(merge_attr))
313 return &ll_merge_drv[LL_TEXT_MERGE];
314 else if (ATTR_FALSE(merge_attr))
315 return &ll_merge_drv[LL_BINARY_MERGE];
316 else if (ATTR_UNSET(merge_attr)) {
317 if (!default_ll_merge)
318 return &ll_merge_drv[LL_TEXT_MERGE];
319 else
320 name = default_ll_merge;
321 }
322 else
323 name = merge_attr;
324 for (fn = ll_user_merge; fn; fn = fn->next)
326 if (!strcmp(fn->name, name))
327 return fn;
328 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
330 if (!strcmp(ll_merge_drv[i].name, name))
331 return &ll_merge_drv[i];
332 /* default to the 3-way */
334 return &ll_merge_drv[LL_TEXT_MERGE];
335}
336static int git_path_check_merge(const char *path, struct git_attr_check check[2])
338{
339 if (!check[0].attr) {
340 check[0].attr = git_attr("merge");
341 check[1].attr = git_attr("conflict-marker-size");
342 }
343 return git_check_attr(path, 2, check);
344}
345static void normalize_file(mmfile_t *mm, const char *path)
347{
348 struct strbuf strbuf = STRBUF_INIT;
349 if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
350 free(mm->ptr);
351 mm->size = strbuf.len;
352 mm->ptr = strbuf_detach(&strbuf, NULL);
353 }
354}
355int ll_merge(mmbuffer_t *result_buf,
357 const char *path,
358 mmfile_t *ancestor, const char *ancestor_label,
359 mmfile_t *ours, const char *our_label,
360 mmfile_t *theirs, const char *their_label,
361 const struct ll_merge_options *opts)
362{
363 static struct git_attr_check check[2];
364 static const struct ll_merge_options default_opts;
365 const char *ll_driver_name = NULL;
366 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
367 const struct ll_merge_driver *driver;
368 if (!opts)
370 opts = &default_opts;
371 if (opts->renormalize) {
373 normalize_file(ancestor, path);
374 normalize_file(ours, path);
375 normalize_file(theirs, path);
376 }
377 if (!git_path_check_merge(path, check)) {
378 ll_driver_name = check[0].value;
379 if (check[1].value) {
380 marker_size = atoi(check[1].value);
381 if (marker_size <= 0)
382 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
383 }
384 }
385 driver = find_ll_merge_driver(ll_driver_name);
386 if (opts->virtual_ancestor && driver->recursive)
387 driver = find_ll_merge_driver(driver->recursive);
388 return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
389 ours, our_label, theirs, their_label,
390 opts, marker_size);
391}
392int ll_merge_marker_size(const char *path)
394{
395 static struct git_attr_check check;
396 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
397 if (!check.attr)
399 check.attr = git_attr("conflict-marker-size");
400 if (!git_check_attr(path, 1, &check) && check.value) {
401 marker_size = atoi(check.value);
402 if (marker_size <= 0)
403 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
404 }
405 return marker_size;
406}