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