git.oblomov.eu Git - git/blob - 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
  13 struct patch_util {
  14         /* For the search for an exact match */
  15         struct hashmap_entry e;
  16         const char *diff, *patch;
  17
  18         int i, shown;
  19         int diffsize;
  20         size_t diff_offset;
  21         /* the index of the matching item in the other branch, or -1 */
  22         int matching;
  23         struct object_id oid;
  24 };
  25
  26 /*
  27  * Reads the patches into a string list, with the `util` field being populated
  28  * as struct object_id (will need to be free()d).
  29  */
  30 static int read_patches(const char *range, struct string_list *list)
  31 {
  32         struct child_process cp = CHILD_PROCESS_INIT;
  33         FILE *in;
  34         struct strbuf buf = STRBUF_INIT, line = STRBUF_INIT;
  35         struct patch_util *util = NULL;
  36         int in_header = 1;
  37
  38         argv_array_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
  39                         "--reverse", "--date-order", "--decorate=no",
  40                         "--no-abbrev-commit", range,
  41                         NULL);
  42         cp.out = -1;
  43         cp.no_stdin = 1;
  44         cp.git_cmd = 1;
  45
  46         if (start_command(&cp))
  47                 return error_errno(_("could not start `log`"));
  48         in = fdopen(cp.out, "r");
  49         if (!in) {
  50                 error_errno(_("could not read `log` output"));
  51                 finish_command(&cp);
  52                 return -1;
  53         }
  54
  55         while (strbuf_getline(&line, in) != EOF) {
  56                 const char *p;
  57
  58                 if (skip_prefix(line.buf, "commit ", &p)) {
  59                         if (util) {
  60                                 string_list_append(list, buf.buf)->util = util;
  61                                 strbuf_reset(&buf);
  62                         }
  63                         util = xcalloc(sizeof(*util), 1);
  64                         if (get_oid(p, &util->oid)) {
  65                                 error(_("could not parse commit '%s'"), p);
  66                                 free(util);
  67                                 string_list_clear(list, 1);
  68                                 strbuf_release(&buf);
  69                                 strbuf_release(&line);
  70                                 fclose(in);
  71                                 finish_command(&cp);
  72                                 return -1;
  73                         }
  74                         util->matching = -1;
  75                         in_header = 1;
  76                         continue;
  77                 }
  78
  79                 if (starts_with(line.buf, "diff --git")) {
  80                         in_header = 0;
  81                         strbuf_addch(&buf, '\n');
  82                         if (!util->diff_offset)
  83                                 util->diff_offset = buf.len;
  84                         strbuf_addbuf(&buf, &line);
  85                 } else if (in_header) {
  86                         if (starts_with(line.buf, "Author: ")) {
  87                                 strbuf_addbuf(&buf, &line);
  88                                 strbuf_addstr(&buf, "\n\n");
  89                         } else if (starts_with(line.buf, "    ")) {
  90                                 strbuf_rtrim(&line);
  91                                 strbuf_addbuf(&buf, &line);
  92                                 strbuf_addch(&buf, '\n');
  93                         }
  94                         continue;
  95                 } else if (starts_with(line.buf, "@@ "))
  96                         strbuf_addstr(&buf, "@@");
  97                 else if (!line.buf[0] || starts_with(line.buf, "index "))
  98                         /*
  99                          * A completely blank (not ' \n', which is context)
 100                          * line is not valid in a diff.  We skip it
 101                          * silently, because this neatly handles the blank
 102                          * separator line between commits in git-log
 103                          * output.
 104                          *
 105                          * We also want to ignore the diff's `index` lines
 106                          * because they contain exact blob hashes in which
 107                          * we are not interested.
 108                          */
 109                         continue;
 110                 else
 111                         strbuf_addbuf(&buf, &line);
 112
 113                 strbuf_addch(&buf, '\n');
 114                 util->diffsize++;
 115         }
 116         fclose(in);
 117         strbuf_release(&line);
 118
 119         if (util)
 120                 string_list_append(list, buf.buf)->util = util;
 121         strbuf_release(&buf);
 122
 123         if (finish_command(&cp))
 124                 return -1;
 125
 126         return 0;
 127 }
 128
 129 static int patch_util_cmp(const void *dummy, const struct patch_util *a,
 130                      const struct patch_util *b, const char *keydata)
 131 {
 132         return strcmp(a->diff, keydata ? keydata : b->diff);
 133 }
 134
 135 static void find_exact_matches(struct string_list *a, struct string_list *b)
 136 {
 137         struct hashmap map;
 138         int i;
 139
 140         hashmap_init(&map, (hashmap_cmp_fn)patch_util_cmp, NULL, 0);
 141
 142         /* First, add the patches of a to a hash map */
 143         for (i = 0; i < a->nr; i++) {
 144                 struct patch_util *util = a->items[i].util;
 145
 146                 util->i = i;
 147                 util->patch = a->items[i].string;
 148                 util->diff = util->patch + util->diff_offset;
 149                 hashmap_entry_init(util, strhash(util->diff));
 150                 hashmap_add(&map, util);
 151         }
 152
 153         /* Now try to find exact matches in b */
 154         for (i = 0; i < b->nr; i++) {
 155                 struct patch_util *util = b->items[i].util, *other;
 156
 157                 util->i = i;
 158                 util->patch = b->items[i].string;
 159                 util->diff = util->patch + util->diff_offset;
 160                 hashmap_entry_init(util, strhash(util->diff));
 161                 other = hashmap_remove(&map, util, NULL);
 162                 if (other) {
 163                         if (other->matching >= 0)
 164                                 BUG("already assigned!");
 165
 166                         other->matching = i;
 167                         util->matching = other->i;
 168                 }
 169         }
 170
 171         hashmap_free(&map, 0);
 172 }
 173
 174 static void diffsize_consume(void *data, char *line, unsigned long len)
 175 {
 176         (*(int *)data)++;
 177 }
 178
 179 static int diffsize(const char *a, const char *b)
 180 {
 181         xpparam_t pp = { 0 };
 182         xdemitconf_t cfg = { 0 };
 183         mmfile_t mf1, mf2;
 184         int count = 0;
 185
 186         mf1.ptr = (char *)a;
 187         mf1.size = strlen(a);
 188         mf2.ptr = (char *)b;
 189         mf2.size = strlen(b);
 190
 191         cfg.ctxlen = 3;
 192         if (!xdi_diff_outf(&mf1, &mf2, diffsize_consume, &count, &pp, &cfg))
 193                 return count;
 194
 195         error(_("failed to generate diff"));
 196         return COST_MAX;
 197 }
 198
 199 static void get_correspondences(struct string_list *a, struct string_list *b,
 200                                 int creation_factor)
 201 {
 202         int n = a->nr + b->nr;
 203         int *cost, c, *a2b, *b2a;
 204         int i, j;
 205
 206         ALLOC_ARRAY(cost, st_mult(n, n));
 207         ALLOC_ARRAY(a2b, n);
 208         ALLOC_ARRAY(b2a, n);
 209
 210         for (i = 0; i < a->nr; i++) {
 211                 struct patch_util *a_util = a->items[i].util;
 212
 213                 for (j = 0; j < b->nr; j++) {
 214                         struct patch_util *b_util = b->items[j].util;
 215
 216                         if (a_util->matching == j)
 217                                 c = 0;
 218                         else if (a_util->matching < 0 && b_util->matching < 0)
 219                                 c = diffsize(a_util->diff, b_util->diff);
 220                         else
 221                                 c = COST_MAX;
 222                         cost[i + n * j] = c;
 223                 }
 224
 225                 c = a_util->matching < 0 ?
 226                         a_util->diffsize * creation_factor / 100 : COST_MAX;
 227                 for (j = b->nr; j < n; j++)
 228                         cost[i + n * j] = c;
 229         }
 230
 231         for (j = 0; j < b->nr; j++) {
 232                 struct patch_util *util = b->items[j].util;
 233
 234                 c = util->matching < 0 ?
 235                         util->diffsize * creation_factor / 100 : COST_MAX;
 236                 for (i = a->nr; i < n; i++)
 237                         cost[i + n * j] = c;
 238         }
 239
 240         for (i = a->nr; i < n; i++)
 241                 for (j = b->nr; j < n; j++)
 242                         cost[i + n * j] = 0;
 243
 244         compute_assignment(n, n, cost, a2b, b2a);
 245
 246         for (i = 0; i < a->nr; i++)
 247                 if (a2b[i] >= 0 && a2b[i] < b->nr) {
 248                         struct patch_util *a_util = a->items[i].util;
 249                         struct patch_util *b_util = b->items[a2b[i]].util;
 250
 251                         a_util->matching = a2b[i];
 252                         b_util->matching = i;
 253                 }
 254
 255         free(cost);
 256         free(a2b);
 257         free(b2a);
 258 }
 259
 260 static void output_pair_header(struct strbuf *buf,
 261                                struct strbuf *dashes,
 262                                struct patch_util *a_util,
 263                                struct patch_util *b_util)
 264 {
 265         struct object_id *oid = a_util ? &a_util->oid : &b_util->oid;
 266         struct commit *commit;
 267
 268         if (!dashes->len)
 269                 strbuf_addchars(dashes, '-',
 270                                 strlen(find_unique_abbrev(oid,
 271                                                           DEFAULT_ABBREV)));
 272
 273         strbuf_reset(buf);
 274         if (!a_util)
 275                 strbuf_addf(buf, "-:  %s ", dashes->buf);
 276         else
 277                 strbuf_addf(buf, "%d:  %s ", a_util->i + 1,
 278                             find_unique_abbrev(&a_util->oid, DEFAULT_ABBREV));
 279
 280         if (!a_util)
 281                 strbuf_addch(buf, '>');
 282         else if (!b_util)
 283                 strbuf_addch(buf, '<');
 284         else if (strcmp(a_util->patch, b_util->patch))
 285                 strbuf_addch(buf, '!');
 286         else
 287                 strbuf_addch(buf, '=');
 288
 289         if (!b_util)
 290                 strbuf_addf(buf, " -:  %s", dashes->buf);
 291         else
 292                 strbuf_addf(buf, " %d:  %s", b_util->i + 1,
 293                             find_unique_abbrev(&b_util->oid, DEFAULT_ABBREV));
 294
 295         commit = lookup_commit_reference(the_repository, oid);
 296         if (commit) {
 297                 strbuf_addch(buf, ' ');
 298                 pp_commit_easy(CMIT_FMT_ONELINE, commit, buf);
 299         }
 300         strbuf_addch(buf, '\n');
 301
 302         fwrite(buf->buf, buf->len, 1, stdout);
 303 }
 304
 305 static struct diff_filespec *get_filespec(const char *name, const char *p)
 306 {
 307         struct diff_filespec *spec = alloc_filespec(name);
 308
 309         fill_filespec(spec, &null_oid, 0, 0644);
 310         spec->data = (char *)p;
 311         spec->size = strlen(p);
 312         spec->should_munmap = 0;
 313         spec->is_stdin = 1;
 314
 315         return spec;
 316 }
 317
 318 static void patch_diff(const char *a, const char *b,
 319                               struct diff_options *diffopt)
 320 {
 321         diff_queue(&diff_queued_diff,
 322                    get_filespec("a", a), get_filespec("b", b));
 323
 324         diffcore_std(diffopt);
 325         diff_flush(diffopt);
 326 }
 327
 328 static void output(struct string_list *a, struct string_list *b,
 329                    struct diff_options *diffopt)
 330 {
 331         struct strbuf buf = STRBUF_INIT, dashes = STRBUF_INIT;
 332         int i = 0, j = 0;
 333
 334         /*
 335          * We assume the user is really more interested in the second argument
 336          * ("newer" version). To that end, we print the output in the order of
 337          * the RHS (the `b` parameter). To put the LHS (the `a` parameter)
 338          * commits that are no longer in the RHS into a good place, we place
 339          * them once we have shown all of their predecessors in the LHS.
 340          */
 341
 342         while (i < a->nr || j < b->nr) {
 343                 struct patch_util *a_util, *b_util;
 344                 a_util = i < a->nr ? a->items[i].util : NULL;
 345                 b_util = j < b->nr ? b->items[j].util : NULL;
 346
 347                 /* Skip all the already-shown commits from the LHS. */
 348                 while (i < a->nr && a_util->shown)
 349                         a_util = ++i < a->nr ? a->items[i].util : NULL;
 350
 351                 /* Show unmatched LHS commit whose predecessors were shown. */
 352                 if (i < a->nr && a_util->matching < 0) {
 353                         output_pair_header(&buf, &dashes, a_util, NULL);
 354                         i++;
 355                         continue;
 356                 }
 357
 358                 /* Show unmatched RHS commits. */
 359                 while (j < b->nr && b_util->matching < 0) {
 360                         output_pair_header(&buf, &dashes, NULL, b_util);
 361                         b_util = ++j < b->nr ? b->items[j].util : NULL;
 362                 }
 363
 364                 /* Show matching LHS/RHS pair. */
 365                 if (j < b->nr) {
 366                         a_util = a->items[b_util->matching].util;
 367                         output_pair_header(&buf, &dashes, a_util, b_util);
 368                         if (!(diffopt->output_format & DIFF_FORMAT_NO_OUTPUT))
 369                                 patch_diff(a->items[b_util->matching].string,
 370                                            b->items[j].string, diffopt);
 371                         a_util->shown = 1;
 372                         j++;
 373                 }
 374         }
 375         strbuf_release(&buf);
 376         strbuf_release(&dashes);
 377 }
 378
 379 int show_range_diff(const char *range1, const char *range2,
 380                     int creation_factor, struct diff_options *diffopt)
 381 {
 382         int res = 0;
 383
 384         struct string_list branch1 = STRING_LIST_INIT_DUP;
 385         struct string_list branch2 = STRING_LIST_INIT_DUP;
 386
 387         if (read_patches(range1, &branch1))
 388                 res = error(_("could not parse log for '%s'"), range1);
 389         if (!res && read_patches(range2, &branch2))
 390                 res = error(_("could not parse log for '%s'"), range2);
 391
 392         if (!res) {
 393                 find_exact_matches(&branch1, &branch2);
 394                 get_correspondences(&branch1, &branch2, creation_factor);
 395                 output(&branch1, &branch2, diffopt);
 396         }
 397
 398         string_list_clear(&branch1, 1);
 399         string_list_clear(&branch2, 1);
 400
 401         return res;
 402 }