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