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 or common ancestor for an internal merge.
50 */
51 if (opts->virtual_ancestor) {
52 stolen = orig;
53 } else {
54 switch (opts->variant) {
55 default:
56 warning("Cannot merge binary files: %s (%s vs. %s)",
57 path, name1, name2);
58 /* fallthru */
59 case XDL_MERGE_FAVOR_OURS:
60 stolen = src1;
61 break;
62 case XDL_MERGE_FAVOR_THEIRS:
63 stolen = src2;
64 break;
65 }
66 }
67 result->ptr = stolen->ptr;
69 result->size = stolen->size;
70 stolen->ptr = NULL;
71 /*
73 * With -Xtheirs or -Xours, we have cleanly merged;
74 * otherwise we got a conflict.
75 */
76 return (opts->variant ? 0 : 1);
77}
78static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
80 mmbuffer_t *result,
81 const char *path,
82 mmfile_t *orig, const char *orig_name,
83 mmfile_t *src1, const char *name1,
84 mmfile_t *src2, const char *name2,
85 const struct ll_merge_options *opts,
86 int marker_size)
87{
88 xmparam_t xmp;
89 assert(opts);
90 if (buffer_is_binary(orig->ptr, orig->size) ||
92 buffer_is_binary(src1->ptr, src1->size) ||
93 buffer_is_binary(src2->ptr, src2->size)) {
94 return ll_binary_merge(drv_unused, result,
95 path,
96 orig, orig_name,
97 src1, name1,
98 src2, name2,
99 opts, marker_size);
100 }
101 memset(&xmp, 0, sizeof(xmp));
103 xmp.level = XDL_MERGE_ZEALOUS;
104 xmp.favor = opts->variant;
105 xmp.xpp.flags = opts->xdl_opts;
106 if (git_xmerge_style >= 0)
107 xmp.style = git_xmerge_style;
108 if (marker_size > 0)
109 xmp.marker_size = marker_size;
110 xmp.ancestor = orig_name;
111 xmp.file1 = name1;
112 xmp.file2 = name2;
113 return xdl_merge(orig, src1, src2, &xmp, result);
114}
115static int ll_union_merge(const struct ll_merge_driver *drv_unused,
117 mmbuffer_t *result,
118 const char *path_unused,
119 mmfile_t *orig, const char *orig_name,
120 mmfile_t *src1, const char *name1,
121 mmfile_t *src2, const char *name2,
122 const struct ll_merge_options *opts,
123 int marker_size)
124{
125 /* Use union favor */
126 struct ll_merge_options o;
127 assert(opts);
128 o = *opts;
129 o.variant = XDL_MERGE_FAVOR_UNION;
130 return ll_xdl_merge(drv_unused, result, path_unused,
131 orig, NULL, src1, NULL, src2, NULL,
132 &o, marker_size);
133}
134#define LL_BINARY_MERGE 0
136#define LL_TEXT_MERGE 1
137#define LL_UNION_MERGE 2
138static struct ll_merge_driver ll_merge_drv[] = {
139 { "binary", "built-in binary merge", ll_binary_merge },
140 { "text", "built-in 3-way text merge", ll_xdl_merge },
141 { "union", "built-in union merge", ll_union_merge },
142};
143static void create_temp(mmfile_t *src, char *path)
145{
146 int fd;
147 strcpy(path, ".merge_file_XXXXXX");
149 fd = xmkstemp(path);
150 if (write_in_full(fd, src->ptr, src->size) != src->size)
151 die_errno("unable to write temp-file");
152 close(fd);
153}
154/*
156 * User defined low-level merge driver support.
157 */
158static int ll_ext_merge(const struct ll_merge_driver *fn,
159 mmbuffer_t *result,
160 const char *path,
161 mmfile_t *orig, const char *orig_name,
162 mmfile_t *src1, const char *name1,
163 mmfile_t *src2, const char *name2,
164 const struct ll_merge_options *opts,
165 int marker_size)
166{
167 char temp[4][50];
168 struct strbuf cmd = STRBUF_INIT;
169 struct strbuf_expand_dict_entry dict[5];
170 const char *args[] = { NULL, NULL };
171 int status, fd, i;
172 struct stat st;
173 assert(opts);
174 dict[0].placeholder = "O"; dict[0].value = temp[0];
176 dict[1].placeholder = "A"; dict[1].value = temp[1];
177 dict[2].placeholder = "B"; dict[2].value = temp[2];
178 dict[3].placeholder = "L"; dict[3].value = temp[3];
179 dict[4].placeholder = NULL; dict[4].value = NULL;
180 if (fn->cmdline == NULL)
182 die("custom merge driver %s lacks command line.", fn->name);
183 result->ptr = NULL;
185 result->size = 0;
186 create_temp(orig, temp[0]);
187 create_temp(src1, temp[1]);
188 create_temp(src2, temp[2]);
189 sprintf(temp[3], "%d", marker_size);
190 strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
192 args[0] = cmd.buf;
194 status = run_command_v_opt(args, RUN_USING_SHELL);
195 fd = open(temp[1], O_RDONLY);
196 if (fd < 0)
197 goto bad;
198 if (fstat(fd, &st))
199 goto close_bad;
200 result->size = st.st_size;
201 result->ptr = xmalloc(result->size + 1);
202 if (read_in_full(fd, result->ptr, result->size) != result->size) {
203 free(result->ptr);
204 result->ptr = NULL;
205 result->size = 0;
206 }
207 close_bad:
208 close(fd);
209 bad:
210 for (i = 0; i < 3; i++)
211 unlink_or_warn(temp[i]);
212 strbuf_release(&cmd);
213 return status;
214}
215/*
217 * merge.default and merge.driver configuration items
218 */
219static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
220static const char *default_ll_merge;
221static int read_merge_config(const char *var, const char *value, void *cb)
223{
224 struct ll_merge_driver *fn;
225 const char *key, *name;
226 int namelen;
227 if (!strcmp(var, "merge.default")) {
229 if (value)
230 default_ll_merge = xstrdup(value);
231 return 0;
232 }
233 /*
235 * We are not interested in anything but "merge.<name>.variable";
236 * especially, we do not want to look at variables such as
237 * "merge.summary", "merge.tool", and "merge.verbosity".
238 */
239 if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
240 return 0;
241 /*
243 * Find existing one as we might be processing merge.<name>.var2
244 * after seeing merge.<name>.var1.
245 */
246 for (fn = ll_user_merge; fn; fn = fn->next)
247 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
248 break;
249 if (!fn) {
250 fn = xcalloc(1, sizeof(struct ll_merge_driver));
251 fn->name = xmemdupz(name, namelen);
252 fn->fn = ll_ext_merge;
253 *ll_user_merge_tail = fn;
254 ll_user_merge_tail = &(fn->next);
255 }
256 if (!strcmp("name", key)) {
258 if (!value)
259 return error("%s: lacks value", var);
260 fn->description = xstrdup(value);
261 return 0;
262 }
263 if (!strcmp("driver", key)) {
265 if (!value)
266 return error("%s: lacks value", var);
267 /*
268 * merge.<name>.driver specifies the command line:
269 *
270 * command-line
271 *
272 * The command-line will be interpolated with the following
273 * tokens and is given to the shell:
274 *
275 * %O - temporary file name for the merge base.
276 * %A - temporary file name for our version.
277 * %B - temporary file name for the other branches' version.
278 * %L - conflict marker length
279 *
280 * The external merge driver should write the results in the
281 * file named by %A, and signal that it has done with zero exit
282 * status.
283 */
284 fn->cmdline = xstrdup(value);
285 return 0;
286 }
287 if (!strcmp("recursive", key)) {
289 if (!value)
290 return error("%s: lacks value", var);
291 fn->recursive = xstrdup(value);
292 return 0;
293 }
294 return 0;
296}
297static void initialize_ll_merge(void)
299{
300 if (ll_user_merge_tail)
301 return;
302 ll_user_merge_tail = &ll_user_merge;
303 git_config(read_merge_config, NULL);
304}
305static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
307{
308 struct ll_merge_driver *fn;
309 const char *name;
310 int i;
311 initialize_ll_merge();
313 if (ATTR_TRUE(merge_attr))
315 return &ll_merge_drv[LL_TEXT_MERGE];
316 else if (ATTR_FALSE(merge_attr))
317 return &ll_merge_drv[LL_BINARY_MERGE];
318 else if (ATTR_UNSET(merge_attr)) {
319 if (!default_ll_merge)
320 return &ll_merge_drv[LL_TEXT_MERGE];
321 else
322 name = default_ll_merge;
323 }
324 else
325 name = merge_attr;
326 for (fn = ll_user_merge; fn; fn = fn->next)
328 if (!strcmp(fn->name, name))
329 return fn;
330 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
332 if (!strcmp(ll_merge_drv[i].name, name))
333 return &ll_merge_drv[i];
334 /* default to the 3-way */
336 return &ll_merge_drv[LL_TEXT_MERGE];
337}
338static int git_path_check_merge(const char *path, struct git_attr_check check[2])
340{
341 if (!check[0].attr) {
342 check[0].attr = git_attr("merge");
343 check[1].attr = git_attr("conflict-marker-size");
344 }
345 return git_check_attr(path, 2, check);
346}
347static void normalize_file(mmfile_t *mm, const char *path)
349{
350 struct strbuf strbuf = STRBUF_INIT;
351 if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
352 free(mm->ptr);
353 mm->size = strbuf.len;
354 mm->ptr = strbuf_detach(&strbuf, NULL);
355 }
356}
357int ll_merge(mmbuffer_t *result_buf,
359 const char *path,
360 mmfile_t *ancestor, const char *ancestor_label,
361 mmfile_t *ours, const char *our_label,
362 mmfile_t *theirs, const char *their_label,
363 const struct ll_merge_options *opts)
364{
365 static struct git_attr_check check[2];
366 static const struct ll_merge_options default_opts;
367 const char *ll_driver_name = NULL;
368 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
369 const struct ll_merge_driver *driver;
370 if (!opts)
372 opts = &default_opts;
373 if (opts->renormalize) {
375 normalize_file(ancestor, path);
376 normalize_file(ours, path);
377 normalize_file(theirs, path);
378 }
379 if (!git_path_check_merge(path, check)) {
380 ll_driver_name = check[0].value;
381 if (check[1].value) {
382 marker_size = atoi(check[1].value);
383 if (marker_size <= 0)
384 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
385 }
386 }
387 driver = find_ll_merge_driver(ll_driver_name);
388 if (opts->virtual_ancestor && driver->recursive)
389 driver = find_ll_merge_driver(driver->recursive);
390 return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
391 ours, our_label, theirs, their_label,
392 opts, marker_size);
393}
394int ll_merge_marker_size(const char *path)
396{
397 static struct git_attr_check check;
398 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
399 if (!check.attr)
401 check.attr = git_attr("conflict-marker-size");
402 if (!git_check_attr(path, 1, &check) && check.value) {
403 marker_size = atoi(check.value);
404 if (marker_size <= 0)
405 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
406 }
407 return marker_size;
408}