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 return git_config_string(&default_ll_merge, var, value);
230 /*
232 * We are not interested in anything but "merge.<name>.variable";
233 * especially, we do not want to look at variables such as
234 * "merge.summary", "merge.tool", and "merge.verbosity".
235 */
236 if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
237 return 0;
238 /*
240 * Find existing one as we might be processing merge.<name>.var2
241 * after seeing merge.<name>.var1.
242 */
243 for (fn = ll_user_merge; fn; fn = fn->next)
244 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
245 break;
246 if (!fn) {
247 fn = xcalloc(1, sizeof(struct ll_merge_driver));
248 fn->name = xmemdupz(name, namelen);
249 fn->fn = ll_ext_merge;
250 *ll_user_merge_tail = fn;
251 ll_user_merge_tail = &(fn->next);
252 }
253 if (!strcmp("name", key))
255 return git_config_string(&fn->description, var, value);
256 if (!strcmp("driver", key)) {
258 if (!value)
259 return error("%s: lacks value", var);
260 /*
261 * merge.<name>.driver specifies the command line:
262 *
263 * command-line
264 *
265 * The command-line will be interpolated with the following
266 * tokens and is given to the shell:
267 *
268 * %O - temporary file name for the merge base.
269 * %A - temporary file name for our version.
270 * %B - temporary file name for the other branches' version.
271 * %L - conflict marker length
272 *
273 * The external merge driver should write the results in the
274 * file named by %A, and signal that it has done with zero exit
275 * status.
276 */
277 fn->cmdline = xstrdup(value);
278 return 0;
279 }
280 if (!strcmp("recursive", key))
282 return git_config_string(&fn->recursive, var, value);
283 return 0;
285}
286static void initialize_ll_merge(void)
288{
289 if (ll_user_merge_tail)
290 return;
291 ll_user_merge_tail = &ll_user_merge;
292 git_config(read_merge_config, NULL);
293}
294static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
296{
297 struct ll_merge_driver *fn;
298 const char *name;
299 int i;
300 initialize_ll_merge();
302 if (ATTR_TRUE(merge_attr))
304 return &ll_merge_drv[LL_TEXT_MERGE];
305 else if (ATTR_FALSE(merge_attr))
306 return &ll_merge_drv[LL_BINARY_MERGE];
307 else if (ATTR_UNSET(merge_attr)) {
308 if (!default_ll_merge)
309 return &ll_merge_drv[LL_TEXT_MERGE];
310 else
311 name = default_ll_merge;
312 }
313 else
314 name = merge_attr;
315 for (fn = ll_user_merge; fn; fn = fn->next)
317 if (!strcmp(fn->name, name))
318 return fn;
319 for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
321 if (!strcmp(ll_merge_drv[i].name, name))
322 return &ll_merge_drv[i];
323 /* default to the 3-way */
325 return &ll_merge_drv[LL_TEXT_MERGE];
326}
327static int git_path_check_merge(const char *path, struct git_attr_check check[2])
329{
330 if (!check[0].attr) {
331 check[0].attr = git_attr("merge");
332 check[1].attr = git_attr("conflict-marker-size");
333 }
334 return git_check_attr(path, 2, check);
335}
336static void normalize_file(mmfile_t *mm, const char *path)
338{
339 struct strbuf strbuf = STRBUF_INIT;
340 if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
341 free(mm->ptr);
342 mm->size = strbuf.len;
343 mm->ptr = strbuf_detach(&strbuf, NULL);
344 }
345}
346int ll_merge(mmbuffer_t *result_buf,
348 const char *path,
349 mmfile_t *ancestor, const char *ancestor_label,
350 mmfile_t *ours, const char *our_label,
351 mmfile_t *theirs, const char *their_label,
352 const struct ll_merge_options *opts)
353{
354 static struct git_attr_check check[2];
355 static const struct ll_merge_options default_opts;
356 const char *ll_driver_name = NULL;
357 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
358 const struct ll_merge_driver *driver;
359 if (!opts)
361 opts = &default_opts;
362 if (opts->renormalize) {
364 normalize_file(ancestor, path);
365 normalize_file(ours, path);
366 normalize_file(theirs, path);
367 }
368 if (!git_path_check_merge(path, check)) {
369 ll_driver_name = check[0].value;
370 if (check[1].value) {
371 marker_size = atoi(check[1].value);
372 if (marker_size <= 0)
373 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
374 }
375 }
376 driver = find_ll_merge_driver(ll_driver_name);
377 if (opts->virtual_ancestor && driver->recursive)
378 driver = find_ll_merge_driver(driver->recursive);
379 return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
380 ours, our_label, theirs, their_label,
381 opts, marker_size);
382}
383int ll_merge_marker_size(const char *path)
385{
386 static struct git_attr_check check;
387 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
388 if (!check.attr)
390 check.attr = git_attr("conflict-marker-size");
391 if (!git_check_attr(path, 1, &check) && check.value) {
392 marker_size = atoi(check.value);
393 if (marker_size <= 0)
394 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
395 }
396 return marker_size;
397}