diff-lib.con commit Provide some linguistic guidance for the documentation. (42e0fae)
   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        int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
  91        unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
  92                              ? CE_MATCH_RACY_IS_DIRTY : 0);
  93
  94        diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
  95
  96        if (diff_unmerged_stage < 0)
  97                diff_unmerged_stage = 2;
  98        entries = active_nr;
  99        for (i = 0; i < entries; i++) {
 100                struct stat st;
 101                unsigned int oldmode, newmode;
 102                struct cache_entry *ce = active_cache[i];
 103                int changed;
 104                unsigned dirty_submodule = 0;
 105
 106                if (diff_can_quit_early(&revs->diffopt))
 107                        break;
 108
 109                if (!ce_path_match(ce, &revs->prune_data))
 110                        continue;
 111
 112                if (ce_stage(ce)) {
 113                        struct combine_diff_path *dpath;
 114                        struct diff_filepair *pair;
 115                        unsigned int wt_mode = 0;
 116                        int num_compare_stages = 0;
 117                        size_t path_len;
 118
 119                        path_len = ce_namelen(ce);
 120
 121                        dpath = xmalloc(combine_diff_path_size(5, path_len));
 122                        dpath->path = (char *) &(dpath->parent[5]);
 123
 124                        dpath->next = NULL;
 125                        dpath->len = path_len;
 126                        memcpy(dpath->path, ce->name, path_len);
 127                        dpath->path[path_len] = '\0';
 128                        hashclr(dpath->sha1);
 129                        memset(&(dpath->parent[0]), 0,
 130                               sizeof(struct combine_diff_parent)*5);
 131
 132                        changed = check_removed(ce, &st);
 133                        if (!changed)
 134                                wt_mode = ce_mode_from_stat(ce, st.st_mode);
 135                        else {
 136                                if (changed < 0) {
 137                                        perror(ce->name);
 138                                        continue;
 139                                }
 140                                if (silent_on_removed)
 141                                        continue;
 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                        if (silent_on_removed)
 208                                continue;
 209                        diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 210                                       ce->sha1, !is_null_sha1(ce->sha1),
 211                                       ce->name, 0);
 212                        continue;
 213                }
 214                changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
 215                                                    ce_option, &dirty_submodule);
 216                if (!changed && !dirty_submodule) {
 217                        ce_mark_uptodate(ce);
 218                        if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 219                                continue;
 220                }
 221                oldmode = ce->ce_mode;
 222                newmode = ce_mode_from_stat(ce, st.st_mode);
 223                diff_change(&revs->diffopt, oldmode, newmode,
 224                            ce->sha1, (changed ? null_sha1 : ce->sha1),
 225                            !is_null_sha1(ce->sha1), (changed ? 0 : !is_null_sha1(ce->sha1)),
 226                            ce->name, 0, dirty_submodule);
 227
 228        }
 229        diffcore_std(&revs->diffopt);
 230        diff_flush(&revs->diffopt);
 231        return 0;
 232}
 233
 234/*
 235 * diff-index
 236 */
 237
 238/* A file entry went away or appeared */
 239static void diff_index_show_file(struct rev_info *revs,
 240                                 const char *prefix,
 241                                 const struct cache_entry *ce,
 242                                 const unsigned char *sha1, int sha1_valid,
 243                                 unsigned int mode,
 244                                 unsigned dirty_submodule)
 245{
 246        diff_addremove(&revs->diffopt, prefix[0], mode,
 247                       sha1, sha1_valid, ce->name, dirty_submodule);
 248}
 249
 250static int get_stat_data(const struct cache_entry *ce,
 251                         const unsigned char **sha1p,
 252                         unsigned int *modep,
 253                         int cached, int match_missing,
 254                         unsigned *dirty_submodule, struct diff_options *diffopt)
 255{
 256        const unsigned char *sha1 = ce->sha1;
 257        unsigned int mode = ce->ce_mode;
 258
 259        if (!cached && !ce_uptodate(ce)) {
 260                int changed;
 261                struct stat st;
 262                changed = check_removed(ce, &st);
 263                if (changed < 0)
 264                        return -1;
 265                else if (changed) {
 266                        if (match_missing) {
 267                                *sha1p = sha1;
 268                                *modep = mode;
 269                                return 0;
 270                        }
 271                        return -1;
 272                }
 273                changed = match_stat_with_submodule(diffopt, ce, &st,
 274                                                    0, dirty_submodule);
 275                if (changed) {
 276                        mode = ce_mode_from_stat(ce, st.st_mode);
 277                        sha1 = null_sha1;
 278                }
 279        }
 280
 281        *sha1p = sha1;
 282        *modep = mode;
 283        return 0;
 284}
 285
 286static void show_new_file(struct rev_info *revs,
 287                          const struct cache_entry *new,
 288                          int cached, int match_missing)
 289{
 290        const unsigned char *sha1;
 291        unsigned int mode;
 292        unsigned dirty_submodule = 0;
 293
 294        /*
 295         * New file in the index: it might actually be different in
 296         * the working tree.
 297         */
 298        if (get_stat_data(new, &sha1, &mode, cached, match_missing,
 299            &dirty_submodule, &revs->diffopt) < 0)
 300                return;
 301
 302        diff_index_show_file(revs, "+", new, sha1, !is_null_sha1(sha1), mode, dirty_submodule);
 303}
 304
 305static int show_modified(struct rev_info *revs,
 306                         const struct cache_entry *old,
 307                         const struct cache_entry *new,
 308                         int report_missing,
 309                         int cached, int match_missing)
 310{
 311        unsigned int mode, oldmode;
 312        const unsigned char *sha1;
 313        unsigned dirty_submodule = 0;
 314
 315        if (get_stat_data(new, &sha1, &mode, cached, match_missing,
 316                          &dirty_submodule, &revs->diffopt) < 0) {
 317                if (report_missing)
 318                        diff_index_show_file(revs, "-", old,
 319                                             old->sha1, 1, old->ce_mode, 0);
 320                return -1;
 321        }
 322
 323        if (revs->combine_merges && !cached &&
 324            (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 325                struct combine_diff_path *p;
 326                int pathlen = ce_namelen(new);
 327
 328                p = xmalloc(combine_diff_path_size(2, pathlen));
 329                p->path = (char *) &p->parent[2];
 330                p->next = NULL;
 331                p->len = pathlen;
 332                memcpy(p->path, new->name, pathlen);
 333                p->path[pathlen] = 0;
 334                p->mode = mode;
 335                hashclr(p->sha1);
 336                memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 337                p->parent[0].status = DIFF_STATUS_MODIFIED;
 338                p->parent[0].mode = new->ce_mode;
 339                hashcpy(p->parent[0].sha1, new->sha1);
 340                p->parent[1].status = DIFF_STATUS_MODIFIED;
 341                p->parent[1].mode = old->ce_mode;
 342                hashcpy(p->parent[1].sha1, old->sha1);
 343                show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 344                free(p);
 345                return 0;
 346        }
 347
 348        oldmode = old->ce_mode;
 349        if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
 350            !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 351                return 0;
 352
 353        diff_change(&revs->diffopt, oldmode, mode,
 354                    old->sha1, sha1, 1, !is_null_sha1(sha1),
 355                    old->name, 0, dirty_submodule);
 356        return 0;
 357}
 358
 359/*
 360 * This gets a mix of an existing index and a tree, one pathname entry
 361 * at a time. The index entry may be a single stage-0 one, but it could
 362 * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 363 * give you the position and number of entries in the index).
 364 */
 365static void do_oneway_diff(struct unpack_trees_options *o,
 366                           const struct cache_entry *idx,
 367                           const struct cache_entry *tree)
 368{
 369        struct rev_info *revs = o->unpack_data;
 370        int match_missing, cached;
 371
 372        /* if the entry is not checked out, don't examine work tree */
 373        cached = o->index_only ||
 374                (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 375        /*
 376         * Backward compatibility wart - "diff-index -m" does
 377         * not mean "do not ignore merges", but "match_missing".
 378         *
 379         * But with the revision flag parsing, that's found in
 380         * "!revs->ignore_merges".
 381         */
 382        match_missing = !revs->ignore_merges;
 383
 384        if (cached && idx && ce_stage(idx)) {
 385                struct diff_filepair *pair;
 386                pair = diff_unmerge(&revs->diffopt, idx->name);
 387                if (tree)
 388                        fill_filespec(pair->one, tree->sha1, 1, tree->ce_mode);
 389                return;
 390        }
 391
 392        /*
 393         * Something added to the tree?
 394         */
 395        if (!tree) {
 396                show_new_file(revs, idx, cached, match_missing);
 397                return;
 398        }
 399
 400        /*
 401         * Something removed from the tree?
 402         */
 403        if (!idx) {
 404                diff_index_show_file(revs, "-", tree, tree->sha1, 1, tree->ce_mode, 0);
 405                return;
 406        }
 407
 408        /* Show difference between old and new */
 409        show_modified(revs, tree, idx, 1, cached, match_missing);
 410}
 411
 412/*
 413 * The unpack_trees() interface is designed for merging, so
 414 * the different source entries are designed primarily for
 415 * the source trees, with the old index being really mainly
 416 * used for being replaced by the result.
 417 *
 418 * For diffing, the index is more important, and we only have a
 419 * single tree.
 420 *
 421 * We're supposed to advance o->pos to skip what we have already processed.
 422 *
 423 * This wrapper makes it all more readable, and takes care of all
 424 * the fairly complex unpack_trees() semantic requirements, including
 425 * the skipping, the path matching, the type conflict cases etc.
 426 */
 427static int oneway_diff(const struct cache_entry * const *src,
 428                       struct unpack_trees_options *o)
 429{
 430        const struct cache_entry *idx = src[0];
 431        const struct cache_entry *tree = src[1];
 432        struct rev_info *revs = o->unpack_data;
 433
 434        /*
 435         * Unpack-trees generates a DF/conflict entry if
 436         * there was a directory in the index and a tree
 437         * in the tree. From a diff standpoint, that's a
 438         * delete of the tree and a create of the file.
 439         */
 440        if (tree == o->df_conflict_entry)
 441                tree = NULL;
 442
 443        if (ce_path_match(idx ? idx : tree, &revs->prune_data)) {
 444                do_oneway_diff(o, idx, tree);
 445                if (diff_can_quit_early(&revs->diffopt)) {
 446                        o->exiting_early = 1;
 447                        return -1;
 448                }
 449        }
 450
 451        return 0;
 452}
 453
 454static int diff_cache(struct rev_info *revs,
 455                      const unsigned char *tree_sha1,
 456                      const char *tree_name,
 457                      int cached)
 458{
 459        struct tree *tree;
 460        struct tree_desc t;
 461        struct unpack_trees_options opts;
 462
 463        tree = parse_tree_indirect(tree_sha1);
 464        if (!tree)
 465                return error("bad tree object %s",
 466                             tree_name ? tree_name : sha1_to_hex(tree_sha1));
 467        memset(&opts, 0, sizeof(opts));
 468        opts.head_idx = 1;
 469        opts.index_only = cached;
 470        opts.diff_index_cached = (cached &&
 471                                  !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
 472        opts.merge = 1;
 473        opts.fn = oneway_diff;
 474        opts.unpack_data = revs;
 475        opts.src_index = &the_index;
 476        opts.dst_index = NULL;
 477        opts.pathspec = &revs->diffopt.pathspec;
 478        opts.pathspec->recursive = 1;
 479        opts.pathspec->max_depth = -1;
 480
 481        init_tree_desc(&t, tree->buffer, tree->size);
 482        return unpack_trees(1, &t, &opts);
 483}
 484
 485int run_diff_index(struct rev_info *revs, int cached)
 486{
 487        struct object_array_entry *ent;
 488
 489        ent = revs->pending.objects;
 490        if (diff_cache(revs, ent->item->sha1, ent->name, cached))
 491                exit(128);
 492
 493        diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 494        diffcore_fix_diff_index(&revs->diffopt);
 495        diffcore_std(&revs->diffopt);
 496        diff_flush(&revs->diffopt);
 497        return 0;
 498}
 499
 500int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 501{
 502        struct rev_info revs;
 503
 504        init_revisions(&revs, NULL);
 505        init_pathspec(&revs.prune_data, opt->pathspec.raw);
 506        revs.diffopt = *opt;
 507
 508        if (diff_cache(&revs, tree_sha1, NULL, 1))
 509                exit(128);
 510        return 0;
 511}
 512
 513int index_differs_from(const char *def, int diff_flags)
 514{
 515        struct rev_info rev;
 516        struct setup_revision_opt opt;
 517
 518        init_revisions(&rev, NULL);
 519        memset(&opt, 0, sizeof(opt));
 520        opt.def = def;
 521        setup_revisions(0, NULL, &rev, &opt);
 522        DIFF_OPT_SET(&rev.diffopt, QUICK);
 523        DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 524        rev.diffopt.flags |= diff_flags;
 525        run_diff_index(&rev, 1);
 526        if (rev.pending.alloc)
 527                free(rev.pending.objects);
 528        return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
 529}