combine-diff.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "diff.h"
   4 #include "diffcore.h"
   5 #include "quote.h"
   6
   7 struct path_list {
   8         struct path_list *next;
   9         int len;
  10         char *path;
  11         unsigned char sha1[20];
  12         unsigned char parent_sha1[FLEX_ARRAY][20];
  13 };
  14
  15 static int uninteresting(struct diff_filepair *p)
  16 {
  17         if (diff_unmodified_pair(p))
  18                 return 1;
  19         if (!S_ISREG(p->one->mode) || !S_ISREG(p->two->mode))
  20                 return 1;
  21         return 0;
  22 }
  23
  24 static struct path_list *intersect_paths(struct path_list *curr,
  25                                          int n, int num_parent)
  26 {
  27         struct diff_queue_struct *q = &diff_queued_diff;
  28         struct path_list *p;
  29         int i;
  30
  31         if (!n) {
  32                 struct path_list *list = NULL, *tail = NULL;
  33                 for (i = 0; i < q->nr; i++) {
  34                         int len;
  35                         const char *path;
  36                         if (uninteresting(q->queue[i]))
  37                                 continue;
  38                         path = q->queue[i]->two->path;
  39                         len = strlen(path);
  40
  41                         p = xmalloc(sizeof(*p) + len + 1 + num_parent * 20);
  42                         p->path = (char*) &(p->parent_sha1[num_parent][0]);
  43                         memcpy(p->path, path, len);
  44                         p->path[len] = 0;
  45                         p->len = len;
  46                         p->next = NULL;
  47                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  48                         memcpy(p->parent_sha1[n], q->queue[i]->one->sha1, 20);
  49                         if (!tail)
  50                                 list = tail = p;
  51                         else {
  52                                 tail->next = p;
  53                                 p = tail;
  54                         }
  55                 }
  56                 return list;
  57         }
  58
  59         for (p = curr; p; p = p->next) {
  60                 int found = 0;
  61                 if (!p->len)
  62                         continue;
  63                 for (i = 0; i < q->nr; i++) {
  64                         const char *path;
  65                         int len;
  66
  67                         if (uninteresting(q->queue[i]))
  68                                 continue;
  69                         path = q->queue[i]->two->path;
  70                         len = strlen(path);
  71                         if (len == p->len && !memcmp(path, p->path, len)) {
  72                                 found = 1;
  73                                 memcpy(p->parent_sha1[n],
  74                                        q->queue[i]->one->sha1, 20);
  75                                 break;
  76                         }
  77                 }
  78                 if (!found)
  79                         p->len = 0;
  80         }
  81         return curr;
  82 }
  83
  84 struct lline {
  85         struct lline *next;
  86         int len;
  87         unsigned long parent_map;
  88         char line[FLEX_ARRAY];
  89 };
  90
  91 struct sline {
  92         struct lline *lost_head, **lost_tail;
  93         char *bol;
  94         int len;
  95         unsigned long flag;
  96 };
  97
  98 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
  99 {
 100         char *blob;
 101         char type[20];
 102         if (!memcmp(sha1, null_sha1, 20)) {
 103                 /* deleted blob */
 104                 *size = 0;
 105                 return xcalloc(1, 1);
 106         }
 107         blob = read_sha1_file(sha1, type, size);
 108         if (strcmp(type, "blob"))
 109                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 110         return blob;
 111 }
 112
 113 #define TMPPATHLEN 50
 114 #define MAXLINELEN 10240
 115
 116 static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
 117 {
 118         int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
 119         if (fd < 0)
 120                 die("unable to create temp-file");
 121         if (write(fd, blob, size) != size)
 122                 die("unable to write temp-file");
 123         close(fd);
 124 }
 125
 126 static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
 127 {
 128         unsigned long size;
 129         void *blob;
 130         blob = grab_blob(sha1, &size);
 131         write_to_temp_file(tmpfile, blob, size);
 132         free(blob);
 133 }
 134
 135 static int parse_num(char **cp_p, unsigned int *num_p)
 136 {
 137         char *cp = *cp_p;
 138         unsigned int num = 0;
 139         int read_some;
 140
 141         while ('0' <= *cp && *cp <= '9')
 142                 num = num * 10 + *cp++ - '0';
 143         if (!(read_some = cp - *cp_p))
 144                 return -1;
 145         *cp_p = cp;
 146         *num_p = num;
 147         return 0;
 148 }
 149
 150 static int parse_hunk_header(char *line, int len,
 151                              unsigned int *ob, unsigned int *on,
 152                              unsigned int *nb, unsigned int *nn)
 153 {
 154         char *cp;
 155         cp = line + 4;
 156         if (parse_num(&cp, ob)) {
 157         bad_line:
 158                 return error("malformed diff output: %s", line);
 159         }
 160         if (*cp == ',') {
 161                 cp++;
 162                 if (parse_num(&cp, on))
 163                         goto bad_line;
 164         }
 165         else
 166                 *on = 1;
 167         if (*cp++ != ' ' || *cp++ != '+')
 168                 goto bad_line;
 169         if (parse_num(&cp, nb))
 170                 goto bad_line;
 171         if (*cp == ',') {
 172                 cp++;
 173                 if (parse_num(&cp, nn))
 174                         goto bad_line;
 175         }
 176         else
 177                 *nn = 1;
 178         return -!!memcmp(cp, " @@", 3);
 179 }
 180
 181 static void append_lost(struct sline *sline, int n, const char *line)
 182 {
 183         struct lline *lline;
 184         int len = strlen(line);
 185         unsigned long this_mask = (1UL<<n);
 186         if (line[len-1] == '\n')
 187                 len--;
 188
 189         /* Check to see if we can squash things */
 190         if (sline->lost_head) {
 191                 struct lline *last_one = NULL;
 192                 /* We cannot squash it with earlier one */
 193                 for (lline = sline->lost_head;
 194                      lline;
 195                      lline = lline->next)
 196                         if (lline->parent_map & this_mask)
 197                                 last_one = lline;
 198                 lline = last_one ? last_one->next : sline->lost_head;
 199                 while (lline) {
 200                         if (lline->len == len &&
 201                             !memcmp(lline->line, line, len)) {
 202                                 lline->parent_map |= this_mask;
 203                                 return;
 204                         }
 205                         lline = lline->next;
 206                 }
 207         }
 208
 209         lline = xmalloc(sizeof(*lline) + len + 1);
 210         lline->len = len;
 211         lline->next = NULL;
 212         lline->parent_map = this_mask;
 213         memcpy(lline->line, line, len);
 214         lline->line[len] = 0;
 215         if (sline->lost_head)
 216                 *(sline->lost_tail) = lline;
 217         else
 218                 sline->lost_head = lline;
 219         sline->lost_tail = &lline->next;
 220 }
 221
 222 static void combine_diff(const unsigned char *parent, const char *ourtmp,
 223                          struct sline *sline, int cnt, int n)
 224 {
 225         FILE *in;
 226         char parent_tmp[TMPPATHLEN];
 227         char cmd[TMPPATHLEN * 2 + 1024];
 228         char line[MAXLINELEN];
 229         unsigned int lno, ob, on, nb, nn;
 230         unsigned long pmask = ~(1UL << n);
 231         struct sline *lost_bucket = NULL;
 232
 233         write_temp_blob(parent_tmp, parent);
 234         sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
 235                 parent_tmp, ourtmp);
 236         in = popen(cmd, "r");
 237         if (!in)
 238                 return;
 239
 240         lno = 1;
 241         while (fgets(line, sizeof(line), in) != NULL) {
 242                 int len = strlen(line);
 243                 if (5 < len && !memcmp("@@ -", line, 4)) {
 244                         if (parse_hunk_header(line, len,
 245                                               &ob, &on, &nb, &nn))
 246                                 break;
 247                         lno = nb;
 248                         if (!nb) {
 249                                 /* @@ -1,2 +0,0 @@ to remove the
 250                                  * first two lines...
 251                                  */
 252                                 nb = 1;
 253                         }
 254                         lost_bucket = &sline[nb-1]; /* sline is 0 based */
 255                         continue;
 256                 }
 257                 if (!lost_bucket)
 258                         continue;
 259                 switch (line[0]) {
 260                 case '-':
 261                         append_lost(lost_bucket, n, line+1);
 262                         break;
 263                 case '+':
 264                         sline[lno-1].flag &= pmask;
 265                         lno++;
 266                         break;
 267                 }
 268         }
 269         fclose(in);
 270         unlink(parent_tmp);
 271 }
 272
 273 static unsigned long context = 3;
 274 static char combine_marker = '@';
 275
 276 static int interesting(struct sline *sline, unsigned long all_mask)
 277 {
 278         return ((sline->flag & all_mask) != all_mask || sline->lost_head);
 279 }
 280
 281 static unsigned long line_diff_parents(struct sline *sline, unsigned long all_mask)
 282 {
 283         /*
 284          * Look at the line and see from which parents we have difference.
 285          * Lower bits of sline->flag records if the parent had this line,
 286          * so XOR with all_mask gives us on-bits for parents we have
 287          * differences with.
 288          */
 289         unsigned long parents = (sline->flag ^ all_mask);
 290         if (sline->lost_head) {
 291                 struct lline *ll;
 292                 for (ll = sline->lost_head; ll; ll = ll->next)
 293                         parents |= ll->parent_map;
 294         }
 295         return parents & all_mask;
 296 }
 297
 298 static void make_hunks(struct sline *sline, unsigned long cnt,
 299                        int num_parent, int dense)
 300 {
 301         unsigned long all_mask = (1UL<<num_parent) - 1;
 302         unsigned long mark = (1UL<<num_parent);
 303         unsigned long i;
 304
 305         i = 0;
 306         while (i < cnt) {
 307                 if (interesting(&sline[i], all_mask)) {
 308                         unsigned long j = (context < i) ? i - context : 0;
 309                         while (j <= i)
 310                                 sline[j++].flag |= mark;
 311                         while (++i < cnt) {
 312                                 if (!interesting(&sline[i], all_mask))
 313                                         break;
 314                                 sline[i].flag |= mark;
 315                         }
 316                         j = (i + context < cnt) ? i + context : cnt;
 317                         while (i < j)
 318                                 sline[i++].flag |= mark;
 319                         continue;
 320                 }
 321                 i++;
 322         }
 323         if (!dense)
 324                 return;
 325
 326         /* Look at each hunk, and if it contains changes from only
 327          * one parent, mark that uninteresting.
 328          */
 329         i = 0;
 330         while (i < cnt) {
 331                 int j, hunk_end, diffs;
 332                 unsigned long parents;
 333                 while (i < cnt && !(sline[i].flag & mark))
 334                         i++;
 335                 if (cnt <= i)
 336                         break; /* No more interesting hunks */
 337                 for (hunk_end = i + 1; hunk_end < cnt; hunk_end++)
 338                         if (!(sline[hunk_end].flag & mark))
 339                                 break;
 340                 /* [i..hunk_end) are interesting.  Now is it from
 341                  * only one parent?
 342                  * If lost lines are only from one parent and
 343                  * remaining lines existed in parents other than
 344                  * that parent, then the hunk is not that interesting.
 345                  */
 346                 parents = 0;
 347                 diffs = 0;
 348                 for (j = i; j < hunk_end; j++)
 349                         parents |= line_diff_parents(sline + j, all_mask);
 350                 /* Now, how many bits from [0..num_parent) are on? */
 351                 for (j = 0; j < num_parent; j++) {
 352                         if (parents & (1UL<<j))
 353                                 diffs++;
 354                 }
 355                 if (diffs < 2) {
 356                         /* This hunk is not that interesting after all */
 357                         for (j = i; j < hunk_end; j++)
 358                                 sline[j].flag &= ~mark;
 359                 }
 360                 i = hunk_end;
 361         }
 362 }
 363
 364 static void dump_sline(struct sline *sline, int cnt, int num_parent)
 365 {
 366         unsigned long mark = (1UL<<num_parent);
 367         int i;
 368         int lno = 0;
 369
 370         while (1) {
 371                 struct sline *sl = &sline[lno];
 372                 int hunk_end;
 373                 while (lno < cnt && !(sline[lno].flag & mark))
 374                         lno++;
 375                 if (cnt <= lno)
 376                         break;
 377                 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
 378                         if (!(sline[hunk_end].flag & mark))
 379                                 break;
 380                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 381                 printf(" +%d,%d ", lno+1, hunk_end-lno);
 382                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 383                 putchar('\n');
 384                 while (lno < hunk_end) {
 385                         struct lline *ll;
 386                         int j;
 387                         sl = &sline[lno++];
 388                         ll = sl->lost_head;
 389                         while (ll) {
 390                                 for (j = 0; j < num_parent; j++) {
 391                                         if (ll->parent_map & (1UL<<j))
 392                                                 putchar('-');
 393                                         else
 394                                                 putchar(' ');
 395                                 }
 396                                 putchar(' ');
 397                                 puts(ll->line);
 398                                 ll = ll->next;
 399                         }
 400                         for (j = 0; j < num_parent; j++) {
 401                                 if ((1UL<<j) & sl->flag)
 402                                         putchar(' ');
 403                                 else
 404                                         putchar('+');
 405                         }
 406                         printf(" %.*s\n", sl->len, sl->bol);
 407                 }
 408         }
 409 }
 410
 411 static void show_combined_diff(struct path_list *elem, int num_parent,
 412                                int dense)
 413 {
 414         unsigned long size, cnt, lno;
 415         char *result, *cp, *ep;
 416         struct sline *sline; /* survived lines */
 417         int i;
 418         char ourtmp[TMPPATHLEN];
 419
 420         /* Read the result of merge first */
 421         result = grab_blob(elem->sha1, &size);
 422         write_to_temp_file(ourtmp, result, size);
 423
 424         for (cnt = 0, cp = result; cp - result < size; cp++) {
 425                 if (*cp == '\n')
 426                         cnt++;
 427         }
 428         if (result[size-1] != '\n')
 429                 cnt++; /* incomplete line */
 430
 431         sline = xcalloc(cnt, sizeof(*sline));
 432         ep = result;
 433         sline[0].bol = result;
 434         for (lno = 0, cp = result; cp - result < size; cp++) {
 435                 if (*cp == '\n') {
 436                         sline[lno].len = cp - sline[lno].bol;
 437                         sline[lno].flag = (1UL<<num_parent) - 1;
 438                         lno++;
 439                         if (lno < cnt)
 440                                 sline[lno].bol = cp + 1;
 441                 }
 442         }
 443         if (result[size-1] != '\n') {
 444                 sline[cnt-1].len = size - (sline[cnt-1].bol - result);
 445                 sline[cnt-1].flag = (1UL<<num_parent) - 1;
 446         }
 447
 448         for (i = 0; i < num_parent; i++)
 449                 combine_diff(elem->parent_sha1[i], ourtmp, sline, cnt, i);
 450
 451         make_hunks(sline, cnt, num_parent, dense);
 452
 453         dump_sline(sline, cnt, num_parent);
 454         unlink(ourtmp);
 455         free(result);
 456
 457         for (i = 0; i < cnt; i++) {
 458                 if (sline[i].lost_head) {
 459                         struct lline *ll = sline[i].lost_head;
 460                         while (ll) {
 461                                 struct lline *tmp = ll;
 462                                 ll = ll->next;
 463                                 free(tmp);
 464                         }
 465                 }
 466         }
 467         free(sline);
 468 }
 469
 470 int diff_tree_combined_merge(const unsigned char *sha1,
 471                              const char *header,
 472                              int show_empty_merge, int dense)
 473 {
 474         struct commit *commit = lookup_commit(sha1);
 475         struct diff_options diffopts;
 476         struct commit_list *parents;
 477         struct path_list *p, *paths = NULL;
 478         int num_parent, i, num_paths;
 479
 480         diff_setup(&diffopts);
 481         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 482         diffopts.recursive = 1;
 483
 484         /* count parents */
 485         for (parents = commit->parents, num_parent = 0;
 486              parents;
 487              parents = parents->next, num_parent++)
 488                 ; /* nothing */
 489
 490         /* find set of paths that everybody touches */
 491         for (parents = commit->parents, i = 0;
 492              parents;
 493              parents = parents->next, i++) {
 494                 struct commit *parent = parents->item;
 495                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 496                                &diffopts);
 497                 paths = intersect_paths(paths, i, num_parent);
 498                 diff_flush(&diffopts);
 499         }
 500
 501         /* find out surviving paths */
 502         for (num_paths = 0, p = paths; p; p = p->next) {
 503                 if (p->len)
 504                         num_paths++;
 505         }
 506         if (num_paths || show_empty_merge) {
 507                 puts(header);
 508                 for (p = paths; p; p = p->next) {
 509                         if (!p->len)
 510                                 continue;
 511                         printf("diff --combined ");
 512                         if (quote_c_style(p->path, NULL, NULL, 0))
 513                                 quote_c_style(p->path, NULL, stdout, 0);
 514                         else
 515                                 printf("%s", p->path);
 516                         putchar('\n');
 517                         show_combined_diff(p, num_parent, dense);
 518                 }
 519         }
 520
 521         /* Clean things up */
 522         while (paths) {
 523                 struct path_list *tmp = paths;
 524                 paths = paths->next;
 525                 free(tmp);
 526         }
 527         return 0;
 528 }