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