tree-diff.con commit Fix multi-glob assertion in git-svn (b47ddef)
   1/*
   2 * Helper functions for tree diff generation
   3 */
   4#include "cache.h"
   5#include "diff.h"
   6#include "diffcore.h"
   7#include "tree.h"
   8
   9static char *malloc_base(const char *base, int baselen, const char *path, int pathlen)
  10{
  11        char *newbase = xmalloc(baselen + pathlen + 2);
  12        memcpy(newbase, base, baselen);
  13        memcpy(newbase + baselen, path, pathlen);
  14        memcpy(newbase + baselen + pathlen, "/", 2);
  15        return newbase;
  16}
  17
  18static char *malloc_fullname(const char *base, int baselen, const char *path, int pathlen)
  19{
  20        char *fullname = xmalloc(baselen + pathlen + 1);
  21        memcpy(fullname, base, baselen);
  22        memcpy(fullname + baselen, path, pathlen);
  23        fullname[baselen + pathlen] = 0;
  24        return fullname;
  25}
  26
  27static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
  28                       const char *base, int baselen);
  29
  30static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
  31{
  32        unsigned mode1, mode2;
  33        const char *path1, *path2;
  34        const unsigned char *sha1, *sha2;
  35        int cmp, pathlen1, pathlen2;
  36        char *fullname;
  37
  38        sha1 = tree_entry_extract(t1, &path1, &mode1);
  39        sha2 = tree_entry_extract(t2, &path2, &mode2);
  40
  41        pathlen1 = tree_entry_len(path1, sha1);
  42        pathlen2 = tree_entry_len(path2, sha2);
  43        cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
  44        if (cmp < 0) {
  45                show_entry(opt, "-", t1, base, baselen);
  46                return -1;
  47        }
  48        if (cmp > 0) {
  49                show_entry(opt, "+", t2, base, baselen);
  50                return 1;
  51        }
  52        if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
  53                return 0;
  54
  55        /*
  56         * If the filemode has changed to/from a directory from/to a regular
  57         * file, we need to consider it a remove and an add.
  58         */
  59        if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
  60                show_entry(opt, "-", t1, base, baselen);
  61                show_entry(opt, "+", t2, base, baselen);
  62                return 0;
  63        }
  64
  65        if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
  66                int retval;
  67                char *newbase = malloc_base(base, baselen, path1, pathlen1);
  68                if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
  69                        newbase[baselen + pathlen1] = 0;
  70                        opt->change(opt, mode1, mode2,
  71                                    sha1, sha2, newbase);
  72                        newbase[baselen + pathlen1] = '/';
  73                }
  74                retval = diff_tree_sha1(sha1, sha2, newbase, opt);
  75                free(newbase);
  76                return retval;
  77        }
  78
  79        fullname = malloc_fullname(base, baselen, path1, pathlen1);
  80        opt->change(opt, mode1, mode2, sha1, sha2, fullname);
  81        free(fullname);
  82        return 0;
  83}
  84
  85/*
  86 * Is a tree entry interesting given the pathspec we have?
  87 *
  88 * Return:
  89 *  - 2 for "yes, and all subsequent entries will be"
  90 *  - 1 for yes
  91 *  - zero for no
  92 *  - negative for "no, and no subsequent entries will be either"
  93 */
  94static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
  95{
  96        const char *path;
  97        const unsigned char *sha1;
  98        unsigned mode;
  99        int i;
 100        int pathlen;
 101        int never_interesting = -1;
 102
 103        if (!opt->nr_paths)
 104                return 1;
 105
 106        sha1 = tree_entry_extract(desc, &path, &mode);
 107
 108        pathlen = tree_entry_len(path, sha1);
 109
 110        for (i = 0; i < opt->nr_paths; i++) {
 111                const char *match = opt->paths[i];
 112                int matchlen = opt->pathlens[i];
 113                int m = -1; /* signals that we haven't called strncmp() */
 114
 115                if (baselen >= matchlen) {
 116                        /* If it doesn't match, move along... */
 117                        if (strncmp(base, match, matchlen))
 118                                continue;
 119
 120                        /*
 121                         * The base is a subdirectory of a path which
 122                         * was specified, so all of them are interesting.
 123                         */
 124                        return 2;
 125                }
 126
 127                /* Does the base match? */
 128                if (strncmp(base, match, baselen))
 129                        continue;
 130
 131                match += baselen;
 132                matchlen -= baselen;
 133
 134                if (never_interesting) {
 135                        /*
 136                         * We have not seen any match that sorts later
 137                         * than the current path.
 138                         */
 139
 140                        /*
 141                         * Does match sort strictly earlier than path
 142                         * with their common parts?
 143                         */
 144                        m = strncmp(match, path,
 145                                    (matchlen < pathlen) ? matchlen : pathlen);
 146                        if (m < 0)
 147                                continue;
 148
 149                        /*
 150                         * If we come here even once, that means there is at
 151                         * least one pathspec that would sort equal to or
 152                         * later than the path we are currently looking at.
 153                         * In other words, if we have never reached this point
 154                         * after iterating all pathspecs, it means all
 155                         * pathspecs are either outside of base, or inside the
 156                         * base but sorts strictly earlier than the current
 157                         * one.  In either case, they will never match the
 158                         * subsequent entries.  In such a case, we initialized
 159                         * the variable to -1 and that is what will be
 160                         * returned, allowing the caller to terminate early.
 161                         */
 162                        never_interesting = 0;
 163                }
 164
 165                if (pathlen > matchlen)
 166                        continue;
 167
 168                if (matchlen > pathlen) {
 169                        if (match[pathlen] != '/')
 170                                continue;
 171                        if (!S_ISDIR(mode))
 172                                continue;
 173                }
 174
 175                if (m == -1)
 176                        /*
 177                         * we cheated and did not do strncmp(), so we do
 178                         * that here.
 179                         */
 180                        m = strncmp(match, path, pathlen);
 181
 182                /*
 183                 * If common part matched earlier then it is a hit,
 184                 * because we rejected the case where path is not a
 185                 * leading directory and is shorter than match.
 186                 */
 187                if (!m)
 188                        return 1;
 189        }
 190        return never_interesting; /* No matches */
 191}
 192
 193/* A whole sub-tree went away or appeared */
 194static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
 195{
 196        int all_interesting = 0;
 197        while (desc->size) {
 198                int show;
 199
 200                if (all_interesting)
 201                        show = 1;
 202                else {
 203                        show = tree_entry_interesting(desc, base, baselen,
 204                                                      opt);
 205                        if (show == 2)
 206                                all_interesting = 1;
 207                }
 208                if (show < 0)
 209                        break;
 210                if (show)
 211                        show_entry(opt, prefix, desc, base, baselen);
 212                update_tree_entry(desc);
 213        }
 214}
 215
 216/* A file entry went away or appeared */
 217static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
 218                       const char *base, int baselen)
 219{
 220        unsigned mode;
 221        const char *path;
 222        const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
 223        int pathlen = tree_entry_len(path, sha1);
 224
 225        if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
 226                enum object_type type;
 227                char *newbase = malloc_base(base, baselen, path, pathlen);
 228                struct tree_desc inner;
 229                void *tree;
 230                unsigned long size;
 231
 232                tree = read_sha1_file(sha1, &type, &size);
 233                if (!tree || type != OBJ_TREE)
 234                        die("corrupt tree sha %s", sha1_to_hex(sha1));
 235
 236                init_tree_desc(&inner, tree, size);
 237                show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
 238
 239                free(tree);
 240                free(newbase);
 241        } else {
 242                char *fullname = malloc_fullname(base, baselen, path, pathlen);
 243                opt->add_remove(opt, prefix[0], mode, sha1, fullname);
 244                free(fullname);
 245        }
 246}
 247
 248static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
 249{
 250        int all_interesting = 0;
 251        while (t->size) {
 252                int show;
 253
 254                if (all_interesting)
 255                        show = 1;
 256                else {
 257                        show = tree_entry_interesting(t, base, baselen, opt);
 258                        if (show == 2)
 259                                all_interesting = 1;
 260                }
 261                if (!show) {
 262                        update_tree_entry(t);
 263                        continue;
 264                }
 265                /* Skip it all? */
 266                if (show < 0)
 267                        t->size = 0;
 268                return;
 269        }
 270}
 271
 272int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 273{
 274        int baselen = strlen(base);
 275
 276        for (;;) {
 277                if (DIFF_OPT_TST(opt, QUIET) && DIFF_OPT_TST(opt, HAS_CHANGES))
 278                        break;
 279                if (opt->nr_paths) {
 280                        skip_uninteresting(t1, base, baselen, opt);
 281                        skip_uninteresting(t2, base, baselen, opt);
 282                }
 283                if (!t1->size) {
 284                        if (!t2->size)
 285                                break;
 286                        show_entry(opt, "+", t2, base, baselen);
 287                        update_tree_entry(t2);
 288                        continue;
 289                }
 290                if (!t2->size) {
 291                        show_entry(opt, "-", t1, base, baselen);
 292                        update_tree_entry(t1);
 293                        continue;
 294                }
 295                switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
 296                case -1:
 297                        update_tree_entry(t1);
 298                        continue;
 299                case 0:
 300                        update_tree_entry(t1);
 301                        /* Fallthrough */
 302                case 1:
 303                        update_tree_entry(t2);
 304                        continue;
 305                }
 306                die("git-diff-tree: internal error");
 307        }
 308        return 0;
 309}
 310
 311/*
 312 * Does it look like the resulting diff might be due to a rename?
 313 *  - single entry
 314 *  - not a valid previous file
 315 */
 316static inline int diff_might_be_rename(void)
 317{
 318        return diff_queued_diff.nr == 1 &&
 319                !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
 320}
 321
 322static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 323{
 324        struct diff_options diff_opts;
 325        struct diff_queue_struct *q = &diff_queued_diff;
 326        struct diff_filepair *choice;
 327        const char *paths[1];
 328        int i;
 329
 330        /* Remove the file creation entry from the diff queue, and remember it */
 331        choice = q->queue[0];
 332        q->nr = 0;
 333
 334        diff_setup(&diff_opts);
 335        DIFF_OPT_SET(&diff_opts, RECURSIVE);
 336        diff_opts.detect_rename = DIFF_DETECT_RENAME;
 337        diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 338        diff_opts.single_follow = opt->paths[0];
 339        diff_opts.break_opt = opt->break_opt;
 340        paths[0] = NULL;
 341        diff_tree_setup_paths(paths, &diff_opts);
 342        if (diff_setup_done(&diff_opts) < 0)
 343                die("unable to set up diff options to follow renames");
 344        diff_tree(t1, t2, base, &diff_opts);
 345        diffcore_std(&diff_opts);
 346        diff_tree_release_paths(&diff_opts);
 347
 348        /* Go through the new set of filepairing, and see if we find a more interesting one */
 349        for (i = 0; i < q->nr; i++) {
 350                struct diff_filepair *p = q->queue[i];
 351
 352                /*
 353                 * Found a source? Not only do we use that for the new
 354                 * diff_queued_diff, we will also use that as the path in
 355                 * the future!
 356                 */
 357                if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) {
 358                        /* Switch the file-pairs around */
 359                        q->queue[i] = choice;
 360                        choice = p;
 361
 362                        /* Update the path we use from now on.. */
 363                        diff_tree_release_paths(opt);
 364                        opt->paths[0] = xstrdup(p->one->path);
 365                        diff_tree_setup_paths(opt->paths, opt);
 366                        break;
 367                }
 368        }
 369
 370        /*
 371         * Then, discard all the non-relevane file pairs...
 372         */
 373        for (i = 0; i < q->nr; i++) {
 374                struct diff_filepair *p = q->queue[i];
 375                diff_free_filepair(p);
 376        }
 377
 378        /*
 379         * .. and re-instate the one we want (which might be either the
 380         * original one, or the rename/copy we found)
 381         */
 382        q->queue[0] = choice;
 383        q->nr = 1;
 384}
 385
 386int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
 387{
 388        void *tree1, *tree2;
 389        struct tree_desc t1, t2;
 390        unsigned long size1, size2;
 391        int retval;
 392
 393        tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
 394        if (!tree1)
 395                die("unable to read source tree (%s)", sha1_to_hex(old));
 396        tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
 397        if (!tree2)
 398                die("unable to read destination tree (%s)", sha1_to_hex(new));
 399        init_tree_desc(&t1, tree1, size1);
 400        init_tree_desc(&t2, tree2, size2);
 401        retval = diff_tree(&t1, &t2, base, opt);
 402        if (DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
 403                init_tree_desc(&t1, tree1, size1);
 404                init_tree_desc(&t2, tree2, size2);
 405                try_to_follow_renames(&t1, &t2, base, opt);
 406        }
 407        free(tree1);
 408        free(tree2);
 409        return retval;
 410}
 411
 412int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
 413{
 414        int retval;
 415        void *tree;
 416        unsigned long size;
 417        struct tree_desc empty, real;
 418
 419        tree = read_object_with_reference(new, tree_type, &size, NULL);
 420        if (!tree)
 421                die("unable to read root tree (%s)", sha1_to_hex(new));
 422        init_tree_desc(&real, tree, size);
 423
 424        init_tree_desc(&empty, "", 0);
 425        retval = diff_tree(&empty, &real, base, opt);
 426        free(tree);
 427        return retval;
 428}
 429
 430static int count_paths(const char **paths)
 431{
 432        int i = 0;
 433        while (*paths++)
 434                i++;
 435        return i;
 436}
 437
 438void diff_tree_release_paths(struct diff_options *opt)
 439{
 440        free(opt->pathlens);
 441}
 442
 443void diff_tree_setup_paths(const char **p, struct diff_options *opt)
 444{
 445        opt->nr_paths = 0;
 446        opt->pathlens = NULL;
 447        opt->paths = NULL;
 448
 449        if (p) {
 450                int i;
 451
 452                opt->paths = p;
 453                opt->nr_paths = count_paths(p);
 454                if (opt->nr_paths == 0) {
 455                        opt->pathlens = NULL;
 456                        return;
 457                }
 458                opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
 459                for (i=0; i < opt->nr_paths; i++)
 460                        opt->pathlens[i] = strlen(p[i]);
 461        }
 462}