Merge branch 'pk/subsub-fetch-fix-take-2' into maint
[git] / range-diff.c
1 #include "cache.h"
2 #include "range-diff.h"
3 #include "string-list.h"
4 #include "run-command.h"
5 #include "strvec.h"
6 #include "hashmap.h"
7 #include "xdiff-interface.h"
8 #include "linear-assignment.h"
9 #include "diffcore.h"
10 #include "commit.h"
11 #include "pretty.h"
12 #include "userdiff.h"
13 #include "apply.h"
14
15 struct patch_util {
16         /* For the search for an exact match */
17         struct hashmap_entry e;
18         const char *diff, *patch;
19
20         int i, shown;
21         int diffsize;
22         size_t diff_offset;
23         /* the index of the matching item in the other branch, or -1 */
24         int matching;
25         struct object_id oid;
26 };
27
28 static size_t find_end_of_line(char *buffer, unsigned long size)
29 {
30         char *eol = memchr(buffer, '\n', size);
31
32         if (!eol)
33                 return size;
34
35         *eol = '\0';
36         return eol + 1 - buffer;
37 }
38
39 /*
40  * Reads the patches into a string list, with the `util` field being populated
41  * as struct object_id (will need to be free()d).
42  */
43 static int read_patches(const char *range, struct string_list *list,
44                         const struct strvec *other_arg)
45 {
46         struct child_process cp = CHILD_PROCESS_INIT;
47         struct strbuf buf = STRBUF_INIT, contents = STRBUF_INIT;
48         struct patch_util *util = NULL;
49         int in_header = 1;
50         char *line, *current_filename = NULL;
51         int offset, len;
52         size_t size;
53
54         strvec_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
55                      "--reverse", "--date-order", "--decorate=no",
56                      "--no-prefix",
57                      /*
58                       * Choose indicators that are not used anywhere
59                       * else in diffs, but still look reasonable
60                       * (e.g. will not be confusing when debugging)
61                       */
62                      "--output-indicator-new=>",
63                      "--output-indicator-old=<",
64                      "--output-indicator-context=#",
65                      "--no-abbrev-commit",
66                      "--pretty=medium",
67                      "--notes",
68                      NULL);
69         if (other_arg)
70                 strvec_pushv(&cp.args, other_arg->v);
71         strvec_push(&cp.args, range);
72         cp.out = -1;
73         cp.no_stdin = 1;
74         cp.git_cmd = 1;
75
76         if (start_command(&cp))
77                 return error_errno(_("could not start `log`"));
78         if (strbuf_read(&contents, cp.out, 0) < 0) {
79                 error_errno(_("could not read `log` output"));
80                 finish_command(&cp);
81                 return -1;
82         }
83
84         line = contents.buf;
85         size = contents.len;
86         for (offset = 0; size > 0; offset += len, size -= len, line += len) {
87                 const char *p;
88
89                 len = find_end_of_line(line, size);
90                 line[len - 1] = '\0';
91                 if (skip_prefix(line, "commit ", &p)) {
92                         if (util) {
93                                 string_list_append(list, buf.buf)->util = util;
94                                 strbuf_reset(&buf);
95                         }
96                         util = xcalloc(sizeof(*util), 1);
97                         if (get_oid(p, &util->oid)) {
98                                 error(_("could not parse commit '%s'"), p);
99                                 free(util);
100                                 string_list_clear(list, 1);
101                                 strbuf_release(&buf);
102                                 strbuf_release(&contents);
103                                 finish_command(&cp);
104                                 return -1;
105                         }
106                         util->matching = -1;
107                         in_header = 1;
108                         continue;
109                 }
110
111                 if (!util) {
112                         error(_("could not parse first line of `log` output: "
113                                 "did not start with 'commit ': '%s'"),
114                               line);
115                         string_list_clear(list, 1);
116                         strbuf_release(&buf);
117                         strbuf_release(&contents);
118                         finish_command(&cp);
119                         return -1;
120                 }
121
122                 if (starts_with(line, "diff --git")) {
123                         struct patch patch = { 0 };
124                         struct strbuf root = STRBUF_INIT;
125                         int linenr = 0;
126                         int orig_len;
127
128                         in_header = 0;
129                         strbuf_addch(&buf, '\n');
130                         if (!util->diff_offset)
131                                 util->diff_offset = buf.len;
132                         line[len - 1] = '\n';
133                         orig_len = len;
134                         len = parse_git_diff_header(&root, &linenr, 0, line,
135                                                     len, size, &patch);
136                         if (len < 0)
137                                 die(_("could not parse git header '%.*s'"),
138                                     orig_len, line);
139                         strbuf_addstr(&buf, " ## ");
140                         if (patch.is_new > 0)
141                                 strbuf_addf(&buf, "%s (new)", patch.new_name);
142                         else if (patch.is_delete > 0)
143                                 strbuf_addf(&buf, "%s (deleted)", patch.old_name);
144                         else if (patch.is_rename)
145                                 strbuf_addf(&buf, "%s => %s", patch.old_name, patch.new_name);
146                         else
147                                 strbuf_addstr(&buf, patch.new_name);
148
149                         free(current_filename);
150                         if (patch.is_delete > 0)
151                                 current_filename = xstrdup(patch.old_name);
152                         else
153                                 current_filename = xstrdup(patch.new_name);
154
155                         if (patch.new_mode && patch.old_mode &&
156                             patch.old_mode != patch.new_mode)
157                                 strbuf_addf(&buf, " (mode change %06o => %06o)",
158                                             patch.old_mode, patch.new_mode);
159
160                         strbuf_addstr(&buf, " ##");
161                 } else if (in_header) {
162                         if (starts_with(line, "Author: ")) {
163                                 strbuf_addstr(&buf, " ## Metadata ##\n");
164                                 strbuf_addstr(&buf, line);
165                                 strbuf_addstr(&buf, "\n\n");
166                                 strbuf_addstr(&buf, " ## Commit message ##\n");
167                         } else if (starts_with(line, "Notes") &&
168                                    line[strlen(line) - 1] == ':') {
169                                 strbuf_addstr(&buf, "\n\n");
170                                 /* strip the trailing colon */
171                                 strbuf_addf(&buf, " ## %.*s ##\n",
172                                             (int)(strlen(line) - 1), line);
173                         } else if (starts_with(line, "    ")) {
174                                 p = line + len - 2;
175                                 while (isspace(*p) && p >= line)
176                                         p--;
177                                 strbuf_add(&buf, line, p - line + 1);
178                                 strbuf_addch(&buf, '\n');
179                         }
180                         continue;
181                 } else if (skip_prefix(line, "@@ ", &p)) {
182                         p = strstr(p, "@@");
183                         strbuf_addstr(&buf, "@@");
184                         if (current_filename && p[2])
185                                 strbuf_addf(&buf, " %s:", current_filename);
186                         if (p)
187                                 strbuf_addstr(&buf, p + 2);
188                 } else if (!line[0])
189                         /*
190                          * A completely blank (not ' \n', which is context)
191                          * line is not valid in a diff.  We skip it
192                          * silently, because this neatly handles the blank
193                          * separator line between commits in git-log
194                          * output.
195                          */
196                         continue;
197                 else if (line[0] == '>') {
198                         strbuf_addch(&buf, '+');
199                         strbuf_addstr(&buf, line + 1);
200                 } else if (line[0] == '<') {
201                         strbuf_addch(&buf, '-');
202                         strbuf_addstr(&buf, line + 1);
203                 } else if (line[0] == '#') {
204                         strbuf_addch(&buf, ' ');
205                         strbuf_addstr(&buf, line + 1);
206                 } else {
207                         strbuf_addch(&buf, ' ');
208                         strbuf_addstr(&buf, line);
209                 }
210
211                 strbuf_addch(&buf, '\n');
212                 util->diffsize++;
213         }
214         strbuf_release(&contents);
215
216         if (util)
217                 string_list_append(list, buf.buf)->util = util;
218         strbuf_release(&buf);
219         free(current_filename);
220
221         if (finish_command(&cp))
222                 return -1;
223
224         return 0;
225 }
226
227 static int patch_util_cmp(const void *dummy, const struct patch_util *a,
228                           const struct patch_util *b, const char *keydata)
229 {
230         return strcmp(a->diff, keydata ? keydata : b->diff);
231 }
232
233 static void find_exact_matches(struct string_list *a, struct string_list *b)
234 {
235         struct hashmap map = HASHMAP_INIT((hashmap_cmp_fn)patch_util_cmp, NULL);
236         int i;
237
238         /* First, add the patches of a to a hash map */
239         for (i = 0; i < a->nr; i++) {
240                 struct patch_util *util = a->items[i].util;
241
242                 util->i = i;
243                 util->patch = a->items[i].string;
244                 util->diff = util->patch + util->diff_offset;
245                 hashmap_entry_init(&util->e, strhash(util->diff));
246                 hashmap_add(&map, &util->e);
247         }
248
249         /* Now try to find exact matches in b */
250         for (i = 0; i < b->nr; i++) {
251                 struct patch_util *util = b->items[i].util, *other;
252
253                 util->i = i;
254                 util->patch = b->items[i].string;
255                 util->diff = util->patch + util->diff_offset;
256                 hashmap_entry_init(&util->e, strhash(util->diff));
257                 other = hashmap_remove_entry(&map, util, e, NULL);
258                 if (other) {
259                         if (other->matching >= 0)
260                                 BUG("already assigned!");
261
262                         other->matching = i;
263                         util->matching = other->i;
264                 }
265         }
266
267         hashmap_clear(&map);
268 }
269
270 static void diffsize_consume(void *data, char *line, unsigned long len)
271 {
272         (*(int *)data)++;
273 }
274
275 static void diffsize_hunk(void *data, long ob, long on, long nb, long nn,
276                           const char *funcline, long funclen)
277 {
278         diffsize_consume(data, NULL, 0);
279 }
280
281 static int diffsize(const char *a, const char *b)
282 {
283         xpparam_t pp = { 0 };
284         xdemitconf_t cfg = { 0 };
285         mmfile_t mf1, mf2;
286         int count = 0;
287
288         mf1.ptr = (char *)a;
289         mf1.size = strlen(a);
290         mf2.ptr = (char *)b;
291         mf2.size = strlen(b);
292
293         cfg.ctxlen = 3;
294         if (!xdi_diff_outf(&mf1, &mf2,
295                            diffsize_hunk, diffsize_consume, &count,
296                            &pp, &cfg))
297                 return count;
298
299         error(_("failed to generate diff"));
300         return COST_MAX;
301 }
302
303 static void get_correspondences(struct string_list *a, struct string_list *b,
304                                 int creation_factor)
305 {
306         int n = a->nr + b->nr;
307         int *cost, c, *a2b, *b2a;
308         int i, j;
309
310         ALLOC_ARRAY(cost, st_mult(n, n));
311         ALLOC_ARRAY(a2b, n);
312         ALLOC_ARRAY(b2a, n);
313
314         for (i = 0; i < a->nr; i++) {
315                 struct patch_util *a_util = a->items[i].util;
316
317                 for (j = 0; j < b->nr; j++) {
318                         struct patch_util *b_util = b->items[j].util;
319
320                         if (a_util->matching == j)
321                                 c = 0;
322                         else if (a_util->matching < 0 && b_util->matching < 0)
323                                 c = diffsize(a_util->diff, b_util->diff);
324                         else
325                                 c = COST_MAX;
326                         cost[i + n * j] = c;
327                 }
328
329                 c = a_util->matching < 0 ?
330                         a_util->diffsize * creation_factor / 100 : COST_MAX;
331                 for (j = b->nr; j < n; j++)
332                         cost[i + n * j] = c;
333         }
334
335         for (j = 0; j < b->nr; j++) {
336                 struct patch_util *util = b->items[j].util;
337
338                 c = util->matching < 0 ?
339                         util->diffsize * creation_factor / 100 : COST_MAX;
340                 for (i = a->nr; i < n; i++)
341                         cost[i + n * j] = c;
342         }
343
344         for (i = a->nr; i < n; i++)
345                 for (j = b->nr; j < n; j++)
346                         cost[i + n * j] = 0;
347
348         compute_assignment(n, n, cost, a2b, b2a);
349
350         for (i = 0; i < a->nr; i++)
351                 if (a2b[i] >= 0 && a2b[i] < b->nr) {
352                         struct patch_util *a_util = a->items[i].util;
353                         struct patch_util *b_util = b->items[a2b[i]].util;
354
355                         a_util->matching = a2b[i];
356                         b_util->matching = i;
357                 }
358
359         free(cost);
360         free(a2b);
361         free(b2a);
362 }
363
364 static void output_pair_header(struct diff_options *diffopt,
365                                int patch_no_width,
366                                struct strbuf *buf,
367                                struct strbuf *dashes,
368                                struct patch_util *a_util,
369                                struct patch_util *b_util)
370 {
371         struct object_id *oid = a_util ? &a_util->oid : &b_util->oid;
372         struct commit *commit;
373         char status;
374         const char *color_reset = diff_get_color_opt(diffopt, DIFF_RESET);
375         const char *color_old = diff_get_color_opt(diffopt, DIFF_FILE_OLD);
376         const char *color_new = diff_get_color_opt(diffopt, DIFF_FILE_NEW);
377         const char *color_commit = diff_get_color_opt(diffopt, DIFF_COMMIT);
378         const char *color;
379
380         if (!dashes->len)
381                 strbuf_addchars(dashes, '-',
382                                 strlen(find_unique_abbrev(oid,
383                                                           DEFAULT_ABBREV)));
384
385         if (!b_util) {
386                 color = color_old;
387                 status = '<';
388         } else if (!a_util) {
389                 color = color_new;
390                 status = '>';
391         } else if (strcmp(a_util->patch, b_util->patch)) {
392                 color = color_commit;
393                 status = '!';
394         } else {
395                 color = color_commit;
396                 status = '=';
397         }
398
399         strbuf_reset(buf);
400         strbuf_addstr(buf, status == '!' ? color_old : color);
401         if (!a_util)
402                 strbuf_addf(buf, "%*s:  %s ", patch_no_width, "-", dashes->buf);
403         else
404                 strbuf_addf(buf, "%*d:  %s ", patch_no_width, a_util->i + 1,
405                             find_unique_abbrev(&a_util->oid, DEFAULT_ABBREV));
406
407         if (status == '!')
408                 strbuf_addf(buf, "%s%s", color_reset, color);
409         strbuf_addch(buf, status);
410         if (status == '!')
411                 strbuf_addf(buf, "%s%s", color_reset, color_new);
412
413         if (!b_util)
414                 strbuf_addf(buf, " %*s:  %s", patch_no_width, "-", dashes->buf);
415         else
416                 strbuf_addf(buf, " %*d:  %s", patch_no_width, b_util->i + 1,
417                             find_unique_abbrev(&b_util->oid, DEFAULT_ABBREV));
418
419         commit = lookup_commit_reference(the_repository, oid);
420         if (commit) {
421                 if (status == '!')
422                         strbuf_addf(buf, "%s%s", color_reset, color);
423
424                 strbuf_addch(buf, ' ');
425                 pp_commit_easy(CMIT_FMT_ONELINE, commit, buf);
426         }
427         strbuf_addf(buf, "%s\n", color_reset);
428
429         fwrite(buf->buf, buf->len, 1, diffopt->file);
430 }
431
432 static struct userdiff_driver section_headers = {
433         .funcname = { "^ ## (.*) ##$\n"
434                       "^.?@@ (.*)$", REG_EXTENDED }
435 };
436
437 static struct diff_filespec *get_filespec(const char *name, const char *p)
438 {
439         struct diff_filespec *spec = alloc_filespec(name);
440
441         fill_filespec(spec, &null_oid, 0, 0100644);
442         spec->data = (char *)p;
443         spec->size = strlen(p);
444         spec->should_munmap = 0;
445         spec->is_stdin = 1;
446         spec->driver = &section_headers;
447
448         return spec;
449 }
450
451 static void patch_diff(const char *a, const char *b,
452                        struct diff_options *diffopt)
453 {
454         diff_queue(&diff_queued_diff,
455                    get_filespec("a", a), get_filespec("b", b));
456
457         diffcore_std(diffopt);
458         diff_flush(diffopt);
459 }
460
461 static void output(struct string_list *a, struct string_list *b,
462                    struct diff_options *diffopt)
463 {
464         struct strbuf buf = STRBUF_INIT, dashes = STRBUF_INIT;
465         int patch_no_width = decimal_width(1 + (a->nr > b->nr ? a->nr : b->nr));
466         int i = 0, j = 0;
467
468         /*
469          * We assume the user is really more interested in the second argument
470          * ("newer" version). To that end, we print the output in the order of
471          * the RHS (the `b` parameter). To put the LHS (the `a` parameter)
472          * commits that are no longer in the RHS into a good place, we place
473          * them once we have shown all of their predecessors in the LHS.
474          */
475
476         while (i < a->nr || j < b->nr) {
477                 struct patch_util *a_util, *b_util;
478                 a_util = i < a->nr ? a->items[i].util : NULL;
479                 b_util = j < b->nr ? b->items[j].util : NULL;
480
481                 /* Skip all the already-shown commits from the LHS. */
482                 while (i < a->nr && a_util->shown)
483                         a_util = ++i < a->nr ? a->items[i].util : NULL;
484
485                 /* Show unmatched LHS commit whose predecessors were shown. */
486                 if (i < a->nr && a_util->matching < 0) {
487                         output_pair_header(diffopt, patch_no_width,
488                                            &buf, &dashes, a_util, NULL);
489                         i++;
490                         continue;
491                 }
492
493                 /* Show unmatched RHS commits. */
494                 while (j < b->nr && b_util->matching < 0) {
495                         output_pair_header(diffopt, patch_no_width,
496                                            &buf, &dashes, NULL, b_util);
497                         b_util = ++j < b->nr ? b->items[j].util : NULL;
498                 }
499
500                 /* Show matching LHS/RHS pair. */
501                 if (j < b->nr) {
502                         a_util = a->items[b_util->matching].util;
503                         output_pair_header(diffopt, patch_no_width,
504                                            &buf, &dashes, a_util, b_util);
505                         if (!(diffopt->output_format & DIFF_FORMAT_NO_OUTPUT))
506                                 patch_diff(a->items[b_util->matching].string,
507                                            b->items[j].string, diffopt);
508                         a_util->shown = 1;
509                         j++;
510                 }
511         }
512         strbuf_release(&buf);
513         strbuf_release(&dashes);
514 }
515
516 static struct strbuf *output_prefix_cb(struct diff_options *opt, void *data)
517 {
518         return data;
519 }
520
521 int show_range_diff(const char *range1, const char *range2,
522                     int creation_factor, int dual_color,
523                     const struct diff_options *diffopt,
524                     const struct strvec *other_arg)
525 {
526         int res = 0;
527
528         struct string_list branch1 = STRING_LIST_INIT_DUP;
529         struct string_list branch2 = STRING_LIST_INIT_DUP;
530
531         if (read_patches(range1, &branch1, other_arg))
532                 res = error(_("could not parse log for '%s'"), range1);
533         if (!res && read_patches(range2, &branch2, other_arg))
534                 res = error(_("could not parse log for '%s'"), range2);
535
536         if (!res) {
537                 struct diff_options opts;
538                 struct strbuf indent = STRBUF_INIT;
539
540                 if (diffopt)
541                         memcpy(&opts, diffopt, sizeof(opts));
542                 else
543                         diff_setup(&opts);
544
545                 if (!opts.output_format)
546                         opts.output_format = DIFF_FORMAT_PATCH;
547                 opts.flags.suppress_diff_headers = 1;
548                 opts.flags.dual_color_diffed_diffs = dual_color;
549                 opts.flags.suppress_hunk_header_line_count = 1;
550                 opts.output_prefix = output_prefix_cb;
551                 strbuf_addstr(&indent, "    ");
552                 opts.output_prefix_data = &indent;
553                 diff_setup_done(&opts);
554
555                 find_exact_matches(&branch1, &branch2);
556                 get_correspondences(&branch1, &branch2, creation_factor);
557                 output(&branch1, &branch2, &opts);
558
559                 strbuf_release(&indent);
560         }
561
562         string_list_clear(&branch1, 1);
563         string_list_clear(&branch2, 1);
564
565         return res;
566 }