git-send-email.perl: Add --to-cmd
[git] / ll-merge.c
1 /*
2  * Low level 3-way in-core file merge.
3  *
4  * Copyright (c) 2007 Junio C Hamano
5  */
6
7 #include "cache.h"
8 #include "attr.h"
9 #include "xdiff-interface.h"
10 #include "run-command.h"
11 #include "ll-merge.h"
12
13 struct ll_merge_driver;
14
15 typedef 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                            int flag,
22                            int marker_size);
23
24 struct 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
33 /*
34  * Built-in low-levels
35  */
36 static 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                            int flag, int marker_size)
43 {
44         /*
45          * The tentative merge result is "ours" for the final round,
46          * or common ancestor for an internal merge.  Still return
47          * "conflicted merge" status.
48          */
49         mmfile_t *stolen = (flag & LL_OPT_VIRTUAL_ANCESTOR) ? orig : src1;
50
51         result->ptr = stolen->ptr;
52         result->size = stolen->size;
53         stolen->ptr = NULL;
54         return 1;
55 }
56
57 static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
58                         mmbuffer_t *result,
59                         const char *path,
60                         mmfile_t *orig, const char *orig_name,
61                         mmfile_t *src1, const char *name1,
62                         mmfile_t *src2, const char *name2,
63                         int flag, int marker_size)
64 {
65         xmparam_t xmp;
66
67         if (buffer_is_binary(orig->ptr, orig->size) ||
68             buffer_is_binary(src1->ptr, src1->size) ||
69             buffer_is_binary(src2->ptr, src2->size)) {
70                 warning("Cannot merge binary files: %s (%s vs. %s)\n",
71                         path, name1, name2);
72                 return ll_binary_merge(drv_unused, result,
73                                        path,
74                                        orig, orig_name,
75                                        src1, name1,
76                                        src2, name2,
77                                        flag, marker_size);
78         }
79
80         memset(&xmp, 0, sizeof(xmp));
81         xmp.level = XDL_MERGE_ZEALOUS;
82         xmp.favor = ll_opt_favor(flag);
83         if (git_xmerge_style >= 0)
84                 xmp.style = git_xmerge_style;
85         if (marker_size > 0)
86                 xmp.marker_size = marker_size;
87         xmp.ancestor = orig_name;
88         xmp.file1 = name1;
89         xmp.file2 = name2;
90         return xdl_merge(orig, src1, src2, &xmp, result);
91 }
92
93 static int ll_union_merge(const struct ll_merge_driver *drv_unused,
94                           mmbuffer_t *result,
95                           const char *path_unused,
96                           mmfile_t *orig, const char *orig_name,
97                           mmfile_t *src1, const char *name1,
98                           mmfile_t *src2, const char *name2,
99                           int flag, int marker_size)
100 {
101         /* Use union favor */
102         flag &= ~LL_OPT_FAVOR_MASK;
103         flag |= create_ll_flag(XDL_MERGE_FAVOR_UNION);
104         return ll_xdl_merge(drv_unused, result, path_unused,
105                             orig, NULL, src1, NULL, src2, NULL,
106                             flag, marker_size);
107         return 0;
108 }
109
110 #define LL_BINARY_MERGE 0
111 #define LL_TEXT_MERGE 1
112 #define LL_UNION_MERGE 2
113 static struct ll_merge_driver ll_merge_drv[] = {
114         { "binary", "built-in binary merge", ll_binary_merge },
115         { "text", "built-in 3-way text merge", ll_xdl_merge },
116         { "union", "built-in union merge", ll_union_merge },
117 };
118
119 static void create_temp(mmfile_t *src, char *path)
120 {
121         int fd;
122
123         strcpy(path, ".merge_file_XXXXXX");
124         fd = xmkstemp(path);
125         if (write_in_full(fd, src->ptr, src->size) != src->size)
126                 die_errno("unable to write temp-file");
127         close(fd);
128 }
129
130 /*
131  * User defined low-level merge driver support.
132  */
133 static int ll_ext_merge(const struct ll_merge_driver *fn,
134                         mmbuffer_t *result,
135                         const char *path,
136                         mmfile_t *orig, const char *orig_name,
137                         mmfile_t *src1, const char *name1,
138                         mmfile_t *src2, const char *name2,
139                         int flag, int marker_size)
140 {
141         char temp[4][50];
142         struct strbuf cmd = STRBUF_INIT;
143         struct strbuf_expand_dict_entry dict[5];
144         const char *args[] = { NULL, NULL };
145         int status, fd, i;
146         struct stat st;
147
148         dict[0].placeholder = "O"; dict[0].value = temp[0];
149         dict[1].placeholder = "A"; dict[1].value = temp[1];
150         dict[2].placeholder = "B"; dict[2].value = temp[2];
151         dict[3].placeholder = "L"; dict[3].value = temp[3];
152         dict[4].placeholder = NULL; dict[4].value = NULL;
153
154         if (fn->cmdline == NULL)
155                 die("custom merge driver %s lacks command line.", fn->name);
156
157         result->ptr = NULL;
158         result->size = 0;
159         create_temp(orig, temp[0]);
160         create_temp(src1, temp[1]);
161         create_temp(src2, temp[2]);
162         sprintf(temp[3], "%d", marker_size);
163
164         strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
165
166         args[0] = cmd.buf;
167         status = run_command_v_opt(args, RUN_USING_SHELL);
168         fd = open(temp[1], O_RDONLY);
169         if (fd < 0)
170                 goto bad;
171         if (fstat(fd, &st))
172                 goto close_bad;
173         result->size = st.st_size;
174         result->ptr = xmalloc(result->size + 1);
175         if (read_in_full(fd, result->ptr, result->size) != result->size) {
176                 free(result->ptr);
177                 result->ptr = NULL;
178                 result->size = 0;
179         }
180  close_bad:
181         close(fd);
182  bad:
183         for (i = 0; i < 3; i++)
184                 unlink_or_warn(temp[i]);
185         strbuf_release(&cmd);
186         return status;
187 }
188
189 /*
190  * merge.default and merge.driver configuration items
191  */
192 static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
193 static const char *default_ll_merge;
194
195 static int read_merge_config(const char *var, const char *value, void *cb)
196 {
197         struct ll_merge_driver *fn;
198         const char *ep, *name;
199         int namelen;
200
201         if (!strcmp(var, "merge.default")) {
202                 if (value)
203                         default_ll_merge = xstrdup(value);
204                 return 0;
205         }
206
207         /*
208          * We are not interested in anything but "merge.<name>.variable";
209          * especially, we do not want to look at variables such as
210          * "merge.summary", "merge.tool", and "merge.verbosity".
211          */
212         if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
213                 return 0;
214
215         /*
216          * Find existing one as we might be processing merge.<name>.var2
217          * after seeing merge.<name>.var1.
218          */
219         name = var + 6;
220         namelen = ep - name;
221         for (fn = ll_user_merge; fn; fn = fn->next)
222                 if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
223                         break;
224         if (!fn) {
225                 fn = xcalloc(1, sizeof(struct ll_merge_driver));
226                 fn->name = xmemdupz(name, namelen);
227                 fn->fn = ll_ext_merge;
228                 *ll_user_merge_tail = fn;
229                 ll_user_merge_tail = &(fn->next);
230         }
231
232         ep++;
233
234         if (!strcmp("name", ep)) {
235                 if (!value)
236                         return error("%s: lacks value", var);
237                 fn->description = xstrdup(value);
238                 return 0;
239         }
240
241         if (!strcmp("driver", ep)) {
242                 if (!value)
243                         return error("%s: lacks value", var);
244                 /*
245                  * merge.<name>.driver specifies the command line:
246                  *
247                  *      command-line
248                  *
249                  * The command-line will be interpolated with the following
250                  * tokens and is given to the shell:
251                  *
252                  *    %O - temporary file name for the merge base.
253                  *    %A - temporary file name for our version.
254                  *    %B - temporary file name for the other branches' version.
255                  *    %L - conflict marker length
256                  *
257                  * The external merge driver should write the results in the
258                  * file named by %A, and signal that it has done with zero exit
259                  * status.
260                  */
261                 fn->cmdline = xstrdup(value);
262                 return 0;
263         }
264
265         if (!strcmp("recursive", ep)) {
266                 if (!value)
267                         return error("%s: lacks value", var);
268                 fn->recursive = xstrdup(value);
269                 return 0;
270         }
271
272         return 0;
273 }
274
275 static void initialize_ll_merge(void)
276 {
277         if (ll_user_merge_tail)
278                 return;
279         ll_user_merge_tail = &ll_user_merge;
280         git_config(read_merge_config, NULL);
281 }
282
283 static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
284 {
285         struct ll_merge_driver *fn;
286         const char *name;
287         int i;
288
289         initialize_ll_merge();
290
291         if (ATTR_TRUE(merge_attr))
292                 return &ll_merge_drv[LL_TEXT_MERGE];
293         else if (ATTR_FALSE(merge_attr))
294                 return &ll_merge_drv[LL_BINARY_MERGE];
295         else if (ATTR_UNSET(merge_attr)) {
296                 if (!default_ll_merge)
297                         return &ll_merge_drv[LL_TEXT_MERGE];
298                 else
299                         name = default_ll_merge;
300         }
301         else
302                 name = merge_attr;
303
304         for (fn = ll_user_merge; fn; fn = fn->next)
305                 if (!strcmp(fn->name, name))
306                         return fn;
307
308         for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
309                 if (!strcmp(ll_merge_drv[i].name, name))
310                         return &ll_merge_drv[i];
311
312         /* default to the 3-way */
313         return &ll_merge_drv[LL_TEXT_MERGE];
314 }
315
316 static int git_path_check_merge(const char *path, struct git_attr_check check[2])
317 {
318         if (!check[0].attr) {
319                 check[0].attr = git_attr("merge");
320                 check[1].attr = git_attr("conflict-marker-size");
321         }
322         return git_checkattr(path, 2, check);
323 }
324
325 static void normalize_file(mmfile_t *mm, const char *path)
326 {
327         struct strbuf strbuf = STRBUF_INIT;
328         if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
329                 free(mm->ptr);
330                 mm->size = strbuf.len;
331                 mm->ptr = strbuf_detach(&strbuf, NULL);
332         }
333 }
334
335 int ll_merge(mmbuffer_t *result_buf,
336              const char *path,
337              mmfile_t *ancestor, const char *ancestor_label,
338              mmfile_t *ours, const char *our_label,
339              mmfile_t *theirs, const char *their_label,
340              int flag)
341 {
342         static struct git_attr_check check[2];
343         const char *ll_driver_name = NULL;
344         int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
345         const struct ll_merge_driver *driver;
346         int virtual_ancestor = flag & LL_OPT_VIRTUAL_ANCESTOR;
347
348         if (flag & LL_OPT_RENORMALIZE) {
349                 normalize_file(ancestor, path);
350                 normalize_file(ours, path);
351                 normalize_file(theirs, path);
352         }
353         if (!git_path_check_merge(path, check)) {
354                 ll_driver_name = check[0].value;
355                 if (check[1].value) {
356                         marker_size = atoi(check[1].value);
357                         if (marker_size <= 0)
358                                 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
359                 }
360         }
361         driver = find_ll_merge_driver(ll_driver_name);
362         if (virtual_ancestor && driver->recursive)
363                 driver = find_ll_merge_driver(driver->recursive);
364         return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
365                           ours, our_label, theirs, their_label,
366                           flag, marker_size);
367 }
368
369 int ll_merge_marker_size(const char *path)
370 {
371         static struct git_attr_check check;
372         int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
373
374         if (!check.attr)
375                 check.attr = git_attr("conflict-marker-size");
376         if (!git_checkattr(path, 1, &check) && check.value) {
377                 marker_size = atoi(check.value);
378                 if (marker_size <= 0)
379                         marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
380         }
381         return marker_size;
382 }