diff-lib.con commit t/README: justify why "! grep foo" is sufficient (53de742)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "commit.h"
   7#include "diff.h"
   8#include "diffcore.h"
   9#include "revision.h"
  10#include "cache-tree.h"
  11#include "unpack-trees.h"
  12#include "refs.h"
  13#include "submodule.h"
  14
  15/*
  16 * diff-files
  17 */
  18
  19/*
  20 * Has the work tree entity been removed?
  21 *
  22 * Return 1 if it was removed from the work tree, 0 if an entity to be
  23 * compared with the cache entry ce still exists (the latter includes
  24 * the case where a directory that is not a submodule repository
  25 * exists for ce that is a submodule -- it is a submodule that is not
  26 * checked out).  Return negative for an error.
  27 */
  28static int check_removed(const struct cache_entry *ce, struct stat *st)
  29{
  30        if (lstat(ce->name, st) < 0) {
  31                if (errno != ENOENT && errno != ENOTDIR)
  32                        return -1;
  33                return 1;
  34        }
  35        if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
  36                return 1;
  37        if (S_ISDIR(st->st_mode)) {
  38                unsigned char sub[20];
  39
  40                /*
  41                 * If ce is already a gitlink, we can have a plain
  42                 * directory (i.e. the submodule is not checked out),
  43                 * or a checked out submodule.  Either case this is not
  44                 * a case where something was removed from the work tree,
  45                 * so we will return 0.
  46                 *
  47                 * Otherwise, if the directory is not a submodule
  48                 * repository, that means ce which was a blob turned into
  49                 * a directory --- the blob was removed!
  50                 */
  51                if (!S_ISGITLINK(ce->ce_mode) &&
  52                    resolve_gitlink_ref(ce->name, "HEAD", sub))
  53                        return 1;
  54        }
  55        return 0;
  56}
  57
  58/*
  59 * Has a file changed or has a submodule new commits or a dirty work tree?
  60 *
  61 * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
  62 * option is set, the caller does not only want to know if a submodule is
  63 * modified at all but wants to know all the conditions that are met (new
  64 * commits, untracked content and/or modified content).
  65 */
  66static int match_stat_with_submodule(struct diff_options *diffopt,
  67                                     const struct cache_entry *ce,
  68                                     struct stat *st, unsigned ce_option,
  69                                     unsigned *dirty_submodule)
  70{
  71        int changed = ce_match_stat(ce, st, ce_option);
  72        if (S_ISGITLINK(ce->ce_mode)) {
  73                unsigned orig_flags = diffopt->flags;
  74                if (!DIFF_OPT_TST(diffopt, OVERRIDE_SUBMODULE_CONFIG))
  75                        set_diffopt_flags_from_submodule_config(diffopt, ce->name);
  76                if (DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES))
  77                        changed = 0;
  78                else if (!DIFF_OPT_TST(diffopt, IGNORE_DIRTY_SUBMODULES)
  79                    && (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES)))
  80                        *dirty_submodule = is_submodule_modified(ce->name, DIFF_OPT_TST(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES));
  81                diffopt->flags = orig_flags;
  82        }
  83        return changed;
  84}
  85
  86int run_diff_files(struct rev_info *revs, unsigned int option)
  87{
  88        int entries, i;
  89        int diff_unmerged_stage = revs->max_count;
  90        unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
  91                              ? CE_MATCH_RACY_IS_DIRTY : 0);
  92
  93        if (option & DIFF_SILENT_ON_REMOVED)
  94                handle_deprecated_show_diff_q(&revs->diffopt);
  95
  96        diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
  97
  98        if (diff_unmerged_stage < 0)
  99                diff_unmerged_stage = 2;
 100        entries = active_nr;
 101        for (i = 0; i < entries; i++) {
 102                struct stat st;
 103                unsigned int oldmode, newmode;
 104                struct cache_entry *ce = active_cache[i];
 105                int changed;
 106                unsigned dirty_submodule = 0;
 107
 108                if (diff_can_quit_early(&revs->diffopt))
 109                        break;
 110
 111                if (!ce_path_match(ce, &revs->prune_data))
 112                        continue;
 113
 114                if (ce_stage(ce)) {
 115                        struct combine_diff_path *dpath;
 116                        struct diff_filepair *pair;
 117                        unsigned int wt_mode = 0;
 118                        int num_compare_stages = 0;
 119                        size_t path_len;
 120
 121                        path_len = ce_namelen(ce);
 122
 123                        dpath = xmalloc(combine_diff_path_size(5, path_len));
 124                        dpath->path = (char *) &(dpath->parent[5]);
 125
 126                        dpath->next = NULL;
 127                        dpath->len = path_len;
 128                        memcpy(dpath->path, ce->name, path_len);
 129                        dpath->path[path_len] = '\0';
 130                        hashclr(dpath->sha1);
 131                        memset(&(dpath->parent[0]), 0,
 132                               sizeof(struct combine_diff_parent)*5);
 133
 134                        changed = check_removed(ce, &st);
 135                        if (!changed)
 136                                wt_mode = ce_mode_from_stat(ce, st.st_mode);
 137                        else {
 138                                if (changed < 0) {
 139                                        perror(ce->name);
 140                                        continue;
 141                                }
 142                                wt_mode = 0;
 143                        }
 144                        dpath->mode = wt_mode;
 145
 146                        while (i < entries) {
 147                                struct cache_entry *nce = active_cache[i];
 148                                int stage;
 149
 150                                if (strcmp(ce->name, nce->name))
 151                                        break;
 152
 153                                /* Stage #2 (ours) is the first parent,
 154                                 * stage #3 (theirs) is the second.
 155                                 */
 156                                stage = ce_stage(nce);
 157                                if (2 <= stage) {
 158                                        int mode = nce->ce_mode;
 159                                        num_compare_stages++;
 160                                        hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 161                                        dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 162                                        dpath->parent[stage-2].status =
 163                                                DIFF_STATUS_MODIFIED;
 164                                }
 165
 166                                /* diff against the proper unmerged stage */
 167                                if (stage == diff_unmerged_stage)
 168                                        ce = nce;
 169                                i++;
 170                        }
 171                        /*
 172                         * Compensate for loop update
 173                         */
 174                        i--;
 175
 176                        if (revs->combine_merges && num_compare_stages == 2) {
 177                                show_combined_diff(dpath, 2,
 178                                                   revs->dense_combined_merges,
 179                                                   revs);
 180                                free(dpath);
 181                                continue;
 182                        }
 183                        free(dpath);
 184                        dpath = NULL;
 185
 186                        /*
 187                         * Show the diff for the 'ce' if we found the one
 188                         * from the desired stage.
 189                         */
 190                        pair = diff_unmerge(&revs->diffopt, ce->name);
 191                        if (wt_mode)
 192                                pair->two->mode = wt_mode;
 193                        if (ce_stage(ce) != diff_unmerged_stage)
 194                                continue;
 195                }
 196
 197                if (ce_uptodate(ce) || ce_skip_worktree(ce))
 198                        continue;
 199
 200                /* If CE_VALID is set, don't look at workdir for file removal */
 201                changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
 202                if (changed) {
 203                        if (changed < 0) {
 204                                perror(ce->name);
 205                                continue;
 206                        }
 207                        diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 208                                       ce->sha1, !is_null_sha1(ce->sha1),
 209                                       ce->name, 0);
 210                        continue;
 211                }
 212                changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
 213                                                    ce_option, &dirty_submodule);
 214                if (!changed && !dirty_submodule) {
 215                        ce_mark_uptodate(ce);
 216                        if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 217                                continue;
 218                }
 219                oldmode = ce->ce_mode;
 220                newmode = ce_mode_from_stat(ce, st.st_mode);
 221                diff_change(&revs->diffopt, oldmode, newmode,
 222                            ce->sha1, (changed ? null_sha1 : ce->sha1),
 223                            !is_null_sha1(ce->sha1), (changed ? 0 : !is_null_sha1(ce->sha1)),
 224                            ce->name, 0, dirty_submodule);
 225
 226        }
 227        diffcore_std(&revs->diffopt);
 228        diff_flush(&revs->diffopt);
 229        return 0;
 230}
 231
 232/*
 233 * diff-index
 234 */
 235
 236/* A file entry went away or appeared */
 237static void diff_index_show_file(struct rev_info *revs,
 238                                 const char *prefix,
 239                                 const struct cache_entry *ce,
 240                                 const unsigned char *sha1, int sha1_valid,
 241                                 unsigned int mode,
 242                                 unsigned dirty_submodule)
 243{
 244        diff_addremove(&revs->diffopt, prefix[0], mode,
 245                       sha1, sha1_valid, ce->name, dirty_submodule);
 246}
 247
 248static int get_stat_data(const struct cache_entry *ce,
 249                         const unsigned char **sha1p,
 250                         unsigned int *modep,
 251                         int cached, int match_missing,
 252                         unsigned *dirty_submodule, struct diff_options *diffopt)
 253{
 254        const unsigned char *sha1 = ce->sha1;
 255        unsigned int mode = ce->ce_mode;
 256
 257        if (!cached && !ce_uptodate(ce)) {
 258                int changed;
 259                struct stat st;
 260                changed = check_removed(ce, &st);
 261                if (changed < 0)
 262                        return -1;
 263                else if (changed) {
 264                        if (match_missing) {
 265                                *sha1p = sha1;
 266                                *modep = mode;
 267                                return 0;
 268                        }
 269                        return -1;
 270                }
 271                changed = match_stat_with_submodule(diffopt, ce, &st,
 272                                                    0, dirty_submodule);
 273                if (changed) {
 274                        mode = ce_mode_from_stat(ce, st.st_mode);
 275                        sha1 = null_sha1;
 276                }
 277        }
 278
 279        *sha1p = sha1;
 280        *modep = mode;
 281        return 0;
 282}
 283
 284static void show_new_file(struct rev_info *revs,
 285                          const struct cache_entry *new,
 286                          int cached, int match_missing)
 287{
 288        const unsigned char *sha1;
 289        unsigned int mode;
 290        unsigned dirty_submodule = 0;
 291
 292        /*
 293         * New file in the index: it might actually be different in
 294         * the working tree.
 295         */
 296        if (get_stat_data(new, &sha1, &mode, cached, match_missing,
 297            &dirty_submodule, &revs->diffopt) < 0)
 298                return;
 299
 300        diff_index_show_file(revs, "+", new, sha1, !is_null_sha1(sha1), mode, dirty_submodule);
 301}
 302
 303static int show_modified(struct rev_info *revs,
 304                         const struct cache_entry *old,
 305                         const struct cache_entry *new,
 306                         int report_missing,
 307                         int cached, int match_missing)
 308{
 309        unsigned int mode, oldmode;
 310        const unsigned char *sha1;
 311        unsigned dirty_submodule = 0;
 312
 313        if (get_stat_data(new, &sha1, &mode, cached, match_missing,
 314                          &dirty_submodule, &revs->diffopt) < 0) {
 315                if (report_missing)
 316                        diff_index_show_file(revs, "-", old,
 317                                             old->sha1, 1, old->ce_mode, 0);
 318                return -1;
 319        }
 320
 321        if (revs->combine_merges && !cached &&
 322            (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 323                struct combine_diff_path *p;
 324                int pathlen = ce_namelen(new);
 325
 326                p = xmalloc(combine_diff_path_size(2, pathlen));
 327                p->path = (char *) &p->parent[2];
 328                p->next = NULL;
 329                p->len = pathlen;
 330                memcpy(p->path, new->name, pathlen);
 331                p->path[pathlen] = 0;
 332                p->mode = mode;
 333                hashclr(p->sha1);
 334                memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 335                p->parent[0].status = DIFF_STATUS_MODIFIED;
 336                p->parent[0].mode = new->ce_mode;
 337                hashcpy(p->parent[0].sha1, new->sha1);
 338                p->parent[1].status = DIFF_STATUS_MODIFIED;
 339                p->parent[1].mode = old->ce_mode;
 340                hashcpy(p->parent[1].sha1, old->sha1);
 341                show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 342                free(p);
 343                return 0;
 344        }
 345
 346        oldmode = old->ce_mode;
 347        if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
 348            !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 349                return 0;
 350
 351        diff_change(&revs->diffopt, oldmode, mode,
 352                    old->sha1, sha1, 1, !is_null_sha1(sha1),
 353                    old->name, 0, dirty_submodule);
 354        return 0;
 355}
 356
 357/*
 358 * This gets a mix of an existing index and a tree, one pathname entry
 359 * at a time. The index entry may be a single stage-0 one, but it could
 360 * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 361 * give you the position and number of entries in the index).
 362 */
 363static void do_oneway_diff(struct unpack_trees_options *o,
 364                           const struct cache_entry *idx,
 365                           const struct cache_entry *tree)
 366{
 367        struct rev_info *revs = o->unpack_data;
 368        int match_missing, cached;
 369
 370        /* if the entry is not checked out, don't examine work tree */
 371        cached = o->index_only ||
 372                (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 373        /*
 374         * Backward compatibility wart - "diff-index -m" does
 375         * not mean "do not ignore merges", but "match_missing".
 376         *
 377         * But with the revision flag parsing, that's found in
 378         * "!revs->ignore_merges".
 379         */
 380        match_missing = !revs->ignore_merges;
 381
 382        if (cached && idx && ce_stage(idx)) {
 383                struct diff_filepair *pair;
 384                pair = diff_unmerge(&revs->diffopt, idx->name);
 385                if (tree)
 386                        fill_filespec(pair->one, tree->sha1, 1, tree->ce_mode);
 387                return;
 388        }
 389
 390        /*
 391         * Something added to the tree?
 392         */
 393        if (!tree) {
 394                show_new_file(revs, idx, cached, match_missing);
 395                return;
 396        }
 397
 398        /*
 399         * Something removed from the tree?
 400         */
 401        if (!idx) {
 402                diff_index_show_file(revs, "-", tree, tree->sha1, 1, tree->ce_mode, 0);
 403                return;
 404        }
 405
 406        /* Show difference between old and new */
 407        show_modified(revs, tree, idx, 1, cached, match_missing);
 408}
 409
 410/*
 411 * The unpack_trees() interface is designed for merging, so
 412 * the different source entries are designed primarily for
 413 * the source trees, with the old index being really mainly
 414 * used for being replaced by the result.
 415 *
 416 * For diffing, the index is more important, and we only have a
 417 * single tree.
 418 *
 419 * We're supposed to advance o->pos to skip what we have already processed.
 420 *
 421 * This wrapper makes it all more readable, and takes care of all
 422 * the fairly complex unpack_trees() semantic requirements, including
 423 * the skipping, the path matching, the type conflict cases etc.
 424 */
 425static int oneway_diff(const struct cache_entry * const *src,
 426                       struct unpack_trees_options *o)
 427{
 428        const struct cache_entry *idx = src[0];
 429        const struct cache_entry *tree = src[1];
 430        struct rev_info *revs = o->unpack_data;
 431
 432        /*
 433         * Unpack-trees generates a DF/conflict entry if
 434         * there was a directory in the index and a tree
 435         * in the tree. From a diff standpoint, that's a
 436         * delete of the tree and a create of the file.
 437         */
 438        if (tree == o->df_conflict_entry)
 439                tree = NULL;
 440
 441        if (ce_path_match(idx ? idx : tree, &revs->prune_data)) {
 442                do_oneway_diff(o, idx, tree);
 443                if (diff_can_quit_early(&revs->diffopt)) {
 444                        o->exiting_early = 1;
 445                        return -1;
 446                }
 447        }
 448
 449        return 0;
 450}
 451
 452static int diff_cache(struct rev_info *revs,
 453                      const unsigned char *tree_sha1,
 454                      const char *tree_name,
 455                      int cached)
 456{
 457        struct tree *tree;
 458        struct tree_desc t;
 459        struct unpack_trees_options opts;
 460
 461        tree = parse_tree_indirect(tree_sha1);
 462        if (!tree)
 463                return error("bad tree object %s",
 464                             tree_name ? tree_name : sha1_to_hex(tree_sha1));
 465        memset(&opts, 0, sizeof(opts));
 466        opts.head_idx = 1;
 467        opts.index_only = cached;
 468        opts.diff_index_cached = (cached &&
 469                                  !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
 470        opts.merge = 1;
 471        opts.fn = oneway_diff;
 472        opts.unpack_data = revs;
 473        opts.src_index = &the_index;
 474        opts.dst_index = NULL;
 475        opts.pathspec = &revs->diffopt.pathspec;
 476        opts.pathspec->recursive = 1;
 477
 478        init_tree_desc(&t, tree->buffer, tree->size);
 479        return unpack_trees(1, &t, &opts);
 480}
 481
 482int run_diff_index(struct rev_info *revs, int cached)
 483{
 484        struct object_array_entry *ent;
 485
 486        ent = revs->pending.objects;
 487        if (diff_cache(revs, ent->item->sha1, ent->name, cached))
 488                exit(128);
 489
 490        diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 491        diffcore_fix_diff_index(&revs->diffopt);
 492        diffcore_std(&revs->diffopt);
 493        diff_flush(&revs->diffopt);
 494        return 0;
 495}
 496
 497int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 498{
 499        struct rev_info revs;
 500
 501        init_revisions(&revs, NULL);
 502        copy_pathspec(&revs.prune_data, &opt->pathspec);
 503        revs.diffopt = *opt;
 504
 505        if (diff_cache(&revs, tree_sha1, NULL, 1))
 506                exit(128);
 507        return 0;
 508}
 509
 510int index_differs_from(const char *def, int diff_flags)
 511{
 512        struct rev_info rev;
 513        struct setup_revision_opt opt;
 514
 515        init_revisions(&rev, NULL);
 516        memset(&opt, 0, sizeof(opt));
 517        opt.def = def;
 518        setup_revisions(0, NULL, &rev, &opt);
 519        DIFF_OPT_SET(&rev.diffopt, QUICK);
 520        DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 521        rev.diffopt.flags |= diff_flags;
 522        run_diff_index(&rev, 1);
 523        if (rev.pending.alloc)
 524                free(rev.pending.objects);
 525        return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
 526}