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_unused,
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 "ours" for the final round,
50 * or common ancestor for an internal merge. Still return
51 * "conflicted merge" status.
52 */
53 stolen = opts->virtual_ancestor ? orig : src1;
54 result->ptr = stolen->ptr;
56 result->size = stolen->size;
57 stolen->ptr = NULL;
58 return 1;
59}
60static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
62 mmbuffer_t *result,
63 const char *path,
64 mmfile_t *orig, const char *orig_name,
65 mmfile_t *src1, const char *name1,
66 mmfile_t *src2, const char *name2,
67 const struct ll_merge_options *opts,
68 int marker_size)
69{
70 xmparam_t xmp;
71 assert(opts);
72 if (buffer_is_binary(orig->ptr, orig->size) ||
74 buffer_is_binary(src1->ptr, src1->size) ||
75 buffer_is_binary(src2->ptr, src2->size)) {
76 warning("Cannot merge binary files: %s (%s vs. %s)\n",
77 path, name1, name2);
78 return ll_binary_merge(drv_unused, result,
79 path,
80 orig, orig_name,
81 src1, name1,
82 src2, name2,
83 opts, marker_size);
84 }
85 memset(&xmp, 0, sizeof(xmp));
87 xmp.level = XDL_MERGE_ZEALOUS;
88 xmp.favor = opts->variant;
89 xmp.xpp.flags = opts->xdl_opts;
90 if (git_xmerge_style >= 0)
91 xmp.style = git_xmerge_style;
92 if (marker_size > 0)
93 xmp.marker_size = marker_size;
94 xmp.ancestor = orig_name;
95 xmp.file1 = name1;
96 xmp.file2 = name2;
97 return xdl_merge(orig, src1, src2, &xmp, result);
98}
99static int ll_union_merge(const struct ll_merge_driver *drv_unused,
101 mmbuffer_t *result,
102 const char *path_unused,
103 mmfile_t *orig, const char *orig_name,
104 mmfile_t *src1, const char *name1,
105 mmfile_t *src2, const char *name2,
106 const struct ll_merge_options *opts,
107 int marker_size)
108{
109 /* Use union favor */
110 struct ll_merge_options o;
111 assert(opts);
112 o = *opts;
113 o.variant = XDL_MERGE_FAVOR_UNION;
114 return ll_xdl_merge(drv_unused, result, path_unused,
115 orig, NULL, src1, NULL, src2, NULL,
116 &o, marker_size);
117}
118#define LL_BINARY_MERGE 0
120#define LL_TEXT_MERGE 1
121#define LL_UNION_MERGE 2
122static struct ll_merge_driver ll_merge_drv[] = {
123 { "binary", "built-in binary merge", ll_binary_merge },
124 { "text", "built-in 3-way text merge", ll_xdl_merge },
125 { "union", "built-in union merge", ll_union_merge },
126};
127static void create_temp(mmfile_t *src, char *path)
129{
130 int fd;
131 strcpy(path, ".merge_file_XXXXXX");
133 fd = xmkstemp(path);
134 if (write_in_full(fd, src->ptr, src->size) != src->size)
135 die_errno("unable to write temp-file");
136 close(fd);
137}
138/*
140 * User defined low-level merge driver support.
141 */
142static int ll_ext_merge(const struct ll_merge_driver *fn,
143 mmbuffer_t *result,
144 const char *path,
145 mmfile_t *orig, const char *orig_name,
146 mmfile_t *src1, const char *name1,
147 mmfile_t *src2, const char *name2,
148 const struct ll_merge_options *opts,
149 int marker_size)
150{
151 char temp[4][50];
152 struct strbuf cmd = STRBUF_INIT;
153 struct strbuf_expand_dict_entry dict[5];
154 const char *args[] = { NULL, NULL };
155 int status, fd, i;
156 struct stat st;
157 assert(opts);
158 dict[0].placeholder = "O"; dict[0].value = temp[0];
160 dict[1].placeholder = "A"; dict[1].value = temp[1];
161 dict[2].placeholder = "B"; dict[2].value = temp[2];
162 dict[3].placeholder = "L"; dict[3].value = temp[3];
163 dict[4].placeholder = NULL; dict[4].value = NULL;
164 if (fn->cmdline == NULL)
166 die("custom merge driver %s lacks command line.", fn->name);
167 result->ptr = NULL;
169 result->size = 0;
170 create_temp(orig, temp[0]);
171 create_temp(src1, temp[1]);
172 create_temp(src2, temp[2]);
173 sprintf(temp[3], "%d", marker_size);
174 strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
176 args[0] = cmd.buf;
178 status = run_command_v_opt(args, RUN_USING_SHELL);
179 fd = open(temp[1], O_RDONLY);
180 if (fd < 0)
181 goto bad;
182 if (fstat(fd, &st))
183 goto close_bad;
184 result->size = st.st_size;
185 result->ptr = xmalloc(result->size + 1);
186 if (read_in_full(fd, result->ptr, result->size) != result->size) {
187 free(result->ptr);
188 result->ptr = NULL;
189 result->size = 0;
190 }
191 close_bad:
192 close(fd);
193 bad:
194 for (i = 0; i < 3; i++)
195 unlink_or_warn(temp[i]);
196 strbuf_release(&cmd);
197 return status;
198}
199/*
201 * merge.default and merge.driver configuration items
202 */
203static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
204static const char *default_ll_merge;
205static int read_merge_config(const char *var, const char *value, void *cb)
207{
208 struct ll_merge_driver *fn;
209 const char *ep, *name;
210 int namelen;
211 if (!strcmp(var, "merge.default")) {
213 if (value)
214 default_ll_merge = xstrdup(value);
215 return 0;
216 }
217 /*
219 * We are not interested in anything but "merge.<name>.variable";
220 * especially, we do not want to look at variables such as
221 * "merge.summary", "merge.tool", and "merge.verbosity".
222 */
223 if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
224 return 0;
225 /*
227 * Find existing one as we might be processing merge.<name>.var2
228 * after seeing merge.<name>.var1.
229 */
230 name = var + 6;
231 namelen = ep - name;
232 for (fn = ll_user_merge; fn; fn = fn->next)
233 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
234 break;
235 if (!fn) {
236 fn = xcalloc(1, sizeof(struct ll_merge_driver));
237 fn->name = xmemdupz(name, namelen);
238 fn->fn = ll_ext_merge;
239 *ll_user_merge_tail = fn;
240 ll_user_merge_tail = &(fn->next);
241 }
242 ep++;
244 if (!strcmp("name", ep)) {
246 if (!value)
247 return error("%s: lacks value", var);
248 fn->description = xstrdup(value);
249 return 0;
250 }
251 if (!strcmp("driver", ep)) {
253 if (!value)
254 return error("%s: lacks value", var);
255 /*
256 * merge.<name>.driver specifies the command line:
257 *
258 * command-line
259 *
260 * The command-line will be interpolated with the following
261 * tokens and is given to the shell:
262 *
263 * %O - temporary file name for the merge base.
264 * %A - temporary file name for our version.
265 * %B - temporary file name for the other branches' version.
266 * %L - conflict marker length
267 *
268 * The external merge driver should write the results in the
269 * file named by %A, and signal that it has done with zero exit
270 * status.
271 */
272 fn->cmdline = xstrdup(value);
273 return 0;
274 }
275 if (!strcmp("recursive", ep)) {
277 if (!value)
278 return error("%s: lacks value", var);
279 fn->recursive = xstrdup(value);
280 return 0;
281 }
282 return 0;
284}
285static void initialize_ll_merge(void)
287{
288 if (ll_user_merge_tail)
289 return;
290 ll_user_merge_tail = &ll_user_merge;
291 git_config(read_merge_config, NULL);
292}
293static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
295{
296 struct ll_merge_driver *fn;
297 const char *name;
298 int i;
299 initialize_ll_merge();
301 if (ATTR_TRUE(merge_attr))
303 return &ll_merge_drv[LL_TEXT_MERGE];
304 else if (ATTR_FALSE(merge_attr))
305 return &ll_merge_drv[LL_BINARY_MERGE];
306 else if (ATTR_UNSET(merge_attr)) {
307 if (!default_ll_merge)
308 return &ll_merge_drv[LL_TEXT_MERGE];
309 else
310 name = default_ll_merge;
311 }
312 else
313 name = merge_attr;
314 for (fn = ll_user_merge; fn; fn = fn->next)
316 if (!strcmp(fn->name, name))
317 return fn;
318 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
320 if (!strcmp(ll_merge_drv[i].name, name))
321 return &ll_merge_drv[i];
322 /* default to the 3-way */
324 return &ll_merge_drv[LL_TEXT_MERGE];
325}
326static int git_path_check_merge(const char *path, struct git_attr_check check[2])
328{
329 if (!check[0].attr) {
330 check[0].attr = git_attr("merge");
331 check[1].attr = git_attr("conflict-marker-size");
332 }
333 return git_checkattr(path, 2, check);
334}
335static void normalize_file(mmfile_t *mm, const char *path)
337{
338 struct strbuf strbuf = STRBUF_INIT;
339 if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
340 free(mm->ptr);
341 mm->size = strbuf.len;
342 mm->ptr = strbuf_detach(&strbuf, NULL);
343 }
344}
345int ll_merge(mmbuffer_t *result_buf,
347 const char *path,
348 mmfile_t *ancestor, const char *ancestor_label,
349 mmfile_t *ours, const char *our_label,
350 mmfile_t *theirs, const char *their_label,
351 const struct ll_merge_options *opts)
352{
353 static struct git_attr_check check[2];
354 const char *ll_driver_name = NULL;
355 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
356 const struct ll_merge_driver *driver;
357 if (!opts) {
359 struct ll_merge_options default_opts = {0};
360 return ll_merge(result_buf, path, ancestor, ancestor_label,
361 ours, our_label, theirs, their_label,
362 &default_opts);
363 }
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_checkattr(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}