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 "config.h"
9#include "attr.h"
10#include "xdiff-interface.h"
11#include "run-command.h"
12#include "ll-merge.h"
13#include "quote.h"
14struct ll_merge_driver;
16typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
18 mmbuffer_t *result,
19 const char *path,
20 mmfile_t *orig, const char *orig_name,
21 mmfile_t *src1, const char *name1,
22 mmfile_t *src2, const char *name2,
23 const struct ll_merge_options *opts,
24 int marker_size);
25struct 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/*
36 * Built-in low-levels
37 */
38static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
39 mmbuffer_t *result,
40 const char *path,
41 mmfile_t *orig, const char *orig_name,
42 mmfile_t *src1, const char *name1,
43 mmfile_t *src2, const char *name2,
44 const struct ll_merge_options *opts,
45 int marker_size)
46{
47 mmfile_t *stolen;
48 assert(opts);
49 /*
51 * The tentative merge result is the common ancestor for an
52 * internal merge. For the final merge, it is "ours" by
53 * default but -Xours/-Xtheirs can tweak the choice.
54 */
55 if (opts->virtual_ancestor) {
56 stolen = orig;
57 } else {
58 switch (opts->variant) {
59 default:
60 warning("Cannot merge binary files: %s (%s vs. %s)",
61 path, name1, name2);
62 /* fallthru */
63 case XDL_MERGE_FAVOR_OURS:
64 stolen = src1;
65 break;
66 case XDL_MERGE_FAVOR_THEIRS:
67 stolen = src2;
68 break;
69 }
70 }
71 result->ptr = stolen->ptr;
73 result->size = stolen->size;
74 stolen->ptr = NULL;
75 /*
77 * With -Xtheirs or -Xours, we have cleanly merged;
78 * otherwise we got a conflict.
79 */
80 return (opts->variant ? 0 : 1);
81}
82static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
84 mmbuffer_t *result,
85 const char *path,
86 mmfile_t *orig, const char *orig_name,
87 mmfile_t *src1, const char *name1,
88 mmfile_t *src2, const char *name2,
89 const struct ll_merge_options *opts,
90 int marker_size)
91{
92 xmparam_t xmp;
93 assert(opts);
94 if (orig->size > MAX_XDIFF_SIZE ||
96 src1->size > MAX_XDIFF_SIZE ||
97 src2->size > MAX_XDIFF_SIZE ||
98 buffer_is_binary(orig->ptr, orig->size) ||
99 buffer_is_binary(src1->ptr, src1->size) ||
100 buffer_is_binary(src2->ptr, src2->size)) {
101 return ll_binary_merge(drv_unused, result,
102 path,
103 orig, orig_name,
104 src1, name1,
105 src2, name2,
106 opts, marker_size);
107 }
108 memset(&xmp, 0, sizeof(xmp));
110 xmp.level = XDL_MERGE_ZEALOUS;
111 xmp.favor = opts->variant;
112 xmp.xpp.flags = opts->xdl_opts;
113 if (git_xmerge_style >= 0)
114 xmp.style = git_xmerge_style;
115 if (marker_size > 0)
116 xmp.marker_size = marker_size;
117 xmp.ancestor = orig_name;
118 xmp.file1 = name1;
119 xmp.file2 = name2;
120 return xdl_merge(orig, src1, src2, &xmp, result);
121}
122static int ll_union_merge(const struct ll_merge_driver *drv_unused,
124 mmbuffer_t *result,
125 const char *path_unused,
126 mmfile_t *orig, const char *orig_name,
127 mmfile_t *src1, const char *name1,
128 mmfile_t *src2, const char *name2,
129 const struct ll_merge_options *opts,
130 int marker_size)
131{
132 /* Use union favor */
133 struct ll_merge_options o;
134 assert(opts);
135 o = *opts;
136 o.variant = XDL_MERGE_FAVOR_UNION;
137 return ll_xdl_merge(drv_unused, result, path_unused,
138 orig, NULL, src1, NULL, src2, NULL,
139 &o, marker_size);
140}
141#define LL_BINARY_MERGE 0
143#define LL_TEXT_MERGE 1
144#define LL_UNION_MERGE 2
145static struct ll_merge_driver ll_merge_drv[] = {
146 { "binary", "built-in binary merge", ll_binary_merge },
147 { "text", "built-in 3-way text merge", ll_xdl_merge },
148 { "union", "built-in union merge", ll_union_merge },
149};
150static void create_temp(mmfile_t *src, char *path, size_t len)
152{
153 int fd;
154 xsnprintf(path, len, ".merge_file_XXXXXX");
156 fd = xmkstemp(path);
157 if (write_in_full(fd, src->ptr, src->size) < 0)
158 die_errno("unable to write temp-file");
159 close(fd);
160}
161/*
163 * User defined low-level merge driver support.
164 */
165static int ll_ext_merge(const struct ll_merge_driver *fn,
166 mmbuffer_t *result,
167 const char *path,
168 mmfile_t *orig, const char *orig_name,
169 mmfile_t *src1, const char *name1,
170 mmfile_t *src2, const char *name2,
171 const struct ll_merge_options *opts,
172 int marker_size)
173{
174 char temp[4][50];
175 struct strbuf cmd = STRBUF_INIT;
176 struct strbuf_expand_dict_entry dict[6];
177 struct strbuf path_sq = STRBUF_INIT;
178 const char *args[] = { NULL, NULL };
179 int status, fd, i;
180 struct stat st;
181 assert(opts);
182 sq_quote_buf(&path_sq, path);
184 dict[0].placeholder = "O"; dict[0].value = temp[0];
185 dict[1].placeholder = "A"; dict[1].value = temp[1];
186 dict[2].placeholder = "B"; dict[2].value = temp[2];
187 dict[3].placeholder = "L"; dict[3].value = temp[3];
188 dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
189 dict[5].placeholder = NULL; dict[5].value = NULL;
190 if (fn->cmdline == NULL)
192 die("custom merge driver %s lacks command line.", fn->name);
193 result->ptr = NULL;
195 result->size = 0;
196 create_temp(orig, temp[0], sizeof(temp[0]));
197 create_temp(src1, temp[1], sizeof(temp[1]));
198 create_temp(src2, temp[2], sizeof(temp[2]));
199 xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
200 strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
202 args[0] = cmd.buf;
204 status = run_command_v_opt(args, RUN_USING_SHELL);
205 fd = open(temp[1], O_RDONLY);
206 if (fd < 0)
207 goto bad;
208 if (fstat(fd, &st))
209 goto close_bad;
210 result->size = st.st_size;
211 result->ptr = xmallocz(result->size);
212 if (read_in_full(fd, result->ptr, result->size) != result->size) {
213 FREE_AND_NULL(result->ptr);
214 result->size = 0;
215 }
216 close_bad:
217 close(fd);
218 bad:
219 for (i = 0; i < 3; i++)
220 unlink_or_warn(temp[i]);
221 strbuf_release(&cmd);
222 strbuf_release(&path_sq);
223 return status;
224}
225/*
227 * merge.default and merge.driver configuration items
228 */
229static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
230static const char *default_ll_merge;
231static int read_merge_config(const char *var, const char *value, void *cb)
233{
234 struct ll_merge_driver *fn;
235 const char *key, *name;
236 int namelen;
237 if (!strcmp(var, "merge.default"))
239 return git_config_string(&default_ll_merge, var, value);
240 /*
242 * We are not interested in anything but "merge.<name>.variable";
243 * especially, we do not want to look at variables such as
244 * "merge.summary", "merge.tool", and "merge.verbosity".
245 */
246 if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
247 return 0;
248 /*
250 * Find existing one as we might be processing merge.<name>.var2
251 * after seeing merge.<name>.var1.
252 */
253 for (fn = ll_user_merge; fn; fn = fn->next)
254 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
255 break;
256 if (!fn) {
257 fn = xcalloc(1, sizeof(struct ll_merge_driver));
258 fn->name = xmemdupz(name, namelen);
259 fn->fn = ll_ext_merge;
260 *ll_user_merge_tail = fn;
261 ll_user_merge_tail = &(fn->next);
262 }
263 if (!strcmp("name", key))
265 return git_config_string(&fn->description, var, value);
266 if (!strcmp("driver", key)) {
268 if (!value)
269 return error("%s: lacks value", var);
270 /*
271 * merge.<name>.driver specifies the command line:
272 *
273 * command-line
274 *
275 * The command-line will be interpolated with the following
276 * tokens and is given to the shell:
277 *
278 * %O - temporary file name for the merge base.
279 * %A - temporary file name for our version.
280 * %B - temporary file name for the other branches' version.
281 * %L - conflict marker length
282 * %P - the original path (safely quoted for the shell)
283 *
284 * The external merge driver should write the results in the
285 * file named by %A, and signal that it has done with zero exit
286 * status.
287 */
288 fn->cmdline = xstrdup(value);
289 return 0;
290 }
291 if (!strcmp("recursive", key))
293 return git_config_string(&fn->recursive, var, value);
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 void normalize_file(mmfile_t *mm, const char *path, struct index_state *istate)
340{
341 struct strbuf strbuf = STRBUF_INIT;
342 if (renormalize_buffer(istate, path, mm->ptr, mm->size, &strbuf)) {
343 free(mm->ptr);
344 mm->size = strbuf.len;
345 mm->ptr = strbuf_detach(&strbuf, NULL);
346 }
347}
348int ll_merge(mmbuffer_t *result_buf,
350 const char *path,
351 mmfile_t *ancestor, const char *ancestor_label,
352 mmfile_t *ours, const char *our_label,
353 mmfile_t *theirs, const char *their_label,
354 struct index_state *istate,
355 const struct ll_merge_options *opts)
356{
357 static struct attr_check *check;
358 static const struct ll_merge_options default_opts;
359 const char *ll_driver_name = NULL;
360 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
361 const struct ll_merge_driver *driver;
362 if (!opts)
364 opts = &default_opts;
365 if (opts->renormalize) {
367 normalize_file(ancestor, path, istate);
368 normalize_file(ours, path, istate);
369 normalize_file(theirs, path, istate);
370 }
371 if (!check)
373 check = attr_check_initl("merge", "conflict-marker-size", NULL);
374 git_check_attr(istate, path, check);
376 ll_driver_name = check->items[0].value;
377 if (check->items[1].value) {
378 marker_size = atoi(check->items[1].value);
379 if (marker_size <= 0)
380 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
381 }
382 driver = find_ll_merge_driver(ll_driver_name);
383 if (opts->virtual_ancestor) {
385 if (driver->recursive)
386 driver = find_ll_merge_driver(driver->recursive);
387 }
388 if (opts->extra_marker_size) {
389 marker_size += opts->extra_marker_size;
390 }
391 return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
392 ours, our_label, theirs, their_label,
393 opts, marker_size);
394}
395int ll_merge_marker_size(struct index_state *istate, const char *path)
397{
398 static struct attr_check *check;
399 int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
400 if (!check)
402 check = attr_check_initl("conflict-marker-size", NULL);
403 git_check_attr(istate, path, check);
404 if (check->items[0].value) {
405 marker_size = atoi(check->items[0].value);
406 if (marker_size <= 0)
407 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
408 }
409 return marker_size;
410}