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