builtin / diff.con commit Merge branch 'jc/doc-git-updates' (ac26684)
   1/*
   2 * Builtin "git diff"
   3 *
   4 * Copyright (c) 2006 Junio C Hamano
   5 */
   6#include "cache.h"
   7#include "color.h"
   8#include "commit.h"
   9#include "blob.h"
  10#include "tag.h"
  11#include "diff.h"
  12#include "diffcore.h"
  13#include "revision.h"
  14#include "log-tree.h"
  15#include "builtin.h"
  16#include "submodule.h"
  17#include "sha1-array.h"
  18
  19struct blobinfo {
  20        unsigned char sha1[20];
  21        const char *name;
  22        unsigned mode;
  23};
  24
  25static const char builtin_diff_usage[] =
  26"git diff [<options>] [<commit> [<commit>]] [--] [<path>...]";
  27
  28static void stuff_change(struct diff_options *opt,
  29                         unsigned old_mode, unsigned new_mode,
  30                         const unsigned char *old_sha1,
  31                         const unsigned char *new_sha1,
  32                         const char *old_name,
  33                         const char *new_name)
  34{
  35        struct diff_filespec *one, *two;
  36
  37        if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
  38            !hashcmp(old_sha1, new_sha1) && (old_mode == new_mode))
  39                return;
  40
  41        if (DIFF_OPT_TST(opt, REVERSE_DIFF)) {
  42                unsigned tmp;
  43                const unsigned char *tmp_u;
  44                const char *tmp_c;
  45                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
  46                tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
  47                tmp_c = old_name; old_name = new_name; new_name = tmp_c;
  48        }
  49
  50        if (opt->prefix &&
  51            (strncmp(old_name, opt->prefix, opt->prefix_length) ||
  52             strncmp(new_name, opt->prefix, opt->prefix_length)))
  53                return;
  54
  55        one = alloc_filespec(old_name);
  56        two = alloc_filespec(new_name);
  57        fill_filespec(one, old_sha1, old_mode);
  58        fill_filespec(two, new_sha1, new_mode);
  59
  60        diff_queue(&diff_queued_diff, one, two);
  61}
  62
  63static int builtin_diff_b_f(struct rev_info *revs,
  64                            int argc, const char **argv,
  65                            struct blobinfo *blob,
  66                            const char *path)
  67{
  68        /* Blob vs file in the working tree*/
  69        struct stat st;
  70
  71        if (argc > 1)
  72                usage(builtin_diff_usage);
  73
  74        if (lstat(path, &st))
  75                die_errno(_("failed to stat '%s'"), path);
  76        if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
  77                die(_("'%s': not a regular file or symlink"), path);
  78
  79        diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
  80
  81        if (blob[0].mode == S_IFINVALID)
  82                blob[0].mode = canon_mode(st.st_mode);
  83
  84        stuff_change(&revs->diffopt,
  85                     blob[0].mode, canon_mode(st.st_mode),
  86                     blob[0].sha1, null_sha1,
  87                     path, path);
  88        diffcore_std(&revs->diffopt);
  89        diff_flush(&revs->diffopt);
  90        return 0;
  91}
  92
  93static int builtin_diff_blobs(struct rev_info *revs,
  94                              int argc, const char **argv,
  95                              struct blobinfo *blob)
  96{
  97        unsigned mode = canon_mode(S_IFREG | 0644);
  98
  99        if (argc > 1)
 100                usage(builtin_diff_usage);
 101
 102        if (blob[0].mode == S_IFINVALID)
 103                blob[0].mode = mode;
 104
 105        if (blob[1].mode == S_IFINVALID)
 106                blob[1].mode = mode;
 107
 108        stuff_change(&revs->diffopt,
 109                     blob[0].mode, blob[1].mode,
 110                     blob[0].sha1, blob[1].sha1,
 111                     blob[0].name, blob[1].name);
 112        diffcore_std(&revs->diffopt);
 113        diff_flush(&revs->diffopt);
 114        return 0;
 115}
 116
 117static int builtin_diff_index(struct rev_info *revs,
 118                              int argc, const char **argv)
 119{
 120        int cached = 0;
 121        while (1 < argc) {
 122                const char *arg = argv[1];
 123                if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
 124                        cached = 1;
 125                else
 126                        usage(builtin_diff_usage);
 127                argv++; argc--;
 128        }
 129        if (!cached)
 130                setup_work_tree();
 131        /*
 132         * Make sure there is one revision (i.e. pending object),
 133         * and there is no revision filtering parameters.
 134         */
 135        if (revs->pending.nr != 1 ||
 136            revs->max_count != -1 || revs->min_age != -1 ||
 137            revs->max_age != -1)
 138                usage(builtin_diff_usage);
 139        if (read_cache_preload(revs->diffopt.pathspec.raw) < 0) {
 140                perror("read_cache_preload");
 141                return -1;
 142        }
 143        return run_diff_index(revs, cached);
 144}
 145
 146static int builtin_diff_tree(struct rev_info *revs,
 147                             int argc, const char **argv,
 148                             struct object_array_entry *ent)
 149{
 150        const unsigned char *(sha1[2]);
 151        int swap = 0;
 152
 153        if (argc > 1)
 154                usage(builtin_diff_usage);
 155
 156        /* We saw two trees, ent[0] and ent[1].
 157         * if ent[1] is uninteresting, they are swapped
 158         */
 159        if (ent[1].item->flags & UNINTERESTING)
 160                swap = 1;
 161        sha1[swap] = ent[0].item->sha1;
 162        sha1[1-swap] = ent[1].item->sha1;
 163        diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
 164        log_tree_diff_flush(revs);
 165        return 0;
 166}
 167
 168static int builtin_diff_combined(struct rev_info *revs,
 169                                 int argc, const char **argv,
 170                                 struct object_array_entry *ent,
 171                                 int ents)
 172{
 173        struct sha1_array parents = SHA1_ARRAY_INIT;
 174        int i;
 175
 176        if (argc > 1)
 177                usage(builtin_diff_usage);
 178
 179        if (!revs->dense_combined_merges && !revs->combine_merges)
 180                revs->dense_combined_merges = revs->combine_merges = 1;
 181        for (i = 1; i < ents; i++)
 182                sha1_array_append(&parents, ent[i].item->sha1);
 183        diff_tree_combined(ent[0].item->sha1, &parents,
 184                           revs->dense_combined_merges, revs);
 185        sha1_array_clear(&parents);
 186        return 0;
 187}
 188
 189static void refresh_index_quietly(void)
 190{
 191        struct lock_file *lock_file;
 192        int fd;
 193
 194        lock_file = xcalloc(1, sizeof(struct lock_file));
 195        fd = hold_locked_index(lock_file, 0);
 196        if (fd < 0)
 197                return;
 198        discard_cache();
 199        read_cache();
 200        refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
 201        update_index_if_able(&the_index, lock_file);
 202}
 203
 204static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
 205{
 206        unsigned int options = 0;
 207
 208        while (1 < argc && argv[1][0] == '-') {
 209                if (!strcmp(argv[1], "--base"))
 210                        revs->max_count = 1;
 211                else if (!strcmp(argv[1], "--ours"))
 212                        revs->max_count = 2;
 213                else if (!strcmp(argv[1], "--theirs"))
 214                        revs->max_count = 3;
 215                else if (!strcmp(argv[1], "-q"))
 216                        options |= DIFF_SILENT_ON_REMOVED;
 217                else if (!strcmp(argv[1], "-h"))
 218                        usage(builtin_diff_usage);
 219                else
 220                        return error(_("invalid option: %s"), argv[1]);
 221                argv++; argc--;
 222        }
 223
 224        /*
 225         * "diff --base" should not combine merges because it was not
 226         * asked to.  "diff -c" should not densify (if the user wants
 227         * dense one, --cc can be explicitly asked for, or just rely
 228         * on the default).
 229         */
 230        if (revs->max_count == -1 && !revs->combine_merges &&
 231            (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 232                revs->combine_merges = revs->dense_combined_merges = 1;
 233
 234        setup_work_tree();
 235        if (read_cache_preload(revs->diffopt.pathspec.raw) < 0) {
 236                perror("read_cache_preload");
 237                return -1;
 238        }
 239        return run_diff_files(revs, options);
 240}
 241
 242int cmd_diff(int argc, const char **argv, const char *prefix)
 243{
 244        int i;
 245        struct rev_info rev;
 246        struct object_array_entry ent[100];
 247        int ents = 0, blobs = 0, paths = 0;
 248        const char *path = NULL;
 249        struct blobinfo blob[2];
 250        int nongit;
 251        int result = 0;
 252
 253        /*
 254         * We could get N tree-ish in the rev.pending_objects list.
 255         * Also there could be M blobs there, and P pathspecs.
 256         *
 257         * N=0, M=0:
 258         *      cache vs files (diff-files)
 259         * N=0, M=2:
 260         *      compare two random blobs.  P must be zero.
 261         * N=0, M=1, P=1:
 262         *      compare a blob with a working tree file.
 263         *
 264         * N=1, M=0:
 265         *      tree vs cache (diff-index --cached)
 266         *
 267         * N=2, M=0:
 268         *      tree vs tree (diff-tree)
 269         *
 270         * N=0, M=0, P=2:
 271         *      compare two filesystem entities (aka --no-index).
 272         *
 273         * Other cases are errors.
 274         */
 275
 276        prefix = setup_git_directory_gently(&nongit);
 277        gitmodules_config();
 278        git_config(git_diff_ui_config, NULL);
 279
 280        init_revisions(&rev, prefix);
 281
 282        /* If this is a no-index diff, just run it and exit there. */
 283        diff_no_index(&rev, argc, argv, nongit, prefix);
 284
 285        /* Otherwise, we are doing the usual "git" diff */
 286        rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 287
 288        /* Scale to real terminal size and respect statGraphWidth config */
 289        rev.diffopt.stat_width = -1;
 290        rev.diffopt.stat_graph_width = -1;
 291
 292        /* Default to let external and textconv be used */
 293        DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
 294        DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
 295
 296        if (nongit)
 297                die(_("Not a git repository"));
 298        argc = setup_revisions(argc, argv, &rev, NULL);
 299        if (!rev.diffopt.output_format) {
 300                rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 301                diff_setup_done(&rev.diffopt);
 302        }
 303
 304        DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
 305
 306        setup_diff_pager(&rev.diffopt);
 307
 308        /*
 309         * Do we have --cached and not have a pending object, then
 310         * default to HEAD by hand.  Eek.
 311         */
 312        if (!rev.pending.nr) {
 313                int i;
 314                for (i = 1; i < argc; i++) {
 315                        const char *arg = argv[i];
 316                        if (!strcmp(arg, "--"))
 317                                break;
 318                        else if (!strcmp(arg, "--cached") ||
 319                                 !strcmp(arg, "--staged")) {
 320                                add_head_to_pending(&rev);
 321                                if (!rev.pending.nr) {
 322                                        struct tree *tree;
 323                                        tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
 324                                        add_pending_object(&rev, &tree->object, "HEAD");
 325                                }
 326                                break;
 327                        }
 328                }
 329        }
 330
 331        for (i = 0; i < rev.pending.nr; i++) {
 332                struct object_array_entry *list = rev.pending.objects+i;
 333                struct object *obj = list->item;
 334                const char *name = list->name;
 335                int flags = (obj->flags & UNINTERESTING);
 336                if (!obj->parsed)
 337                        obj = parse_object(obj->sha1);
 338                obj = deref_tag(obj, NULL, 0);
 339                if (!obj)
 340                        die(_("invalid object '%s' given."), name);
 341                if (obj->type == OBJ_COMMIT)
 342                        obj = &((struct commit *)obj)->tree->object;
 343                if (obj->type == OBJ_TREE) {
 344                        if (ARRAY_SIZE(ent) <= ents)
 345                                die(_("more than %d trees given: '%s'"),
 346                                    (int) ARRAY_SIZE(ent), name);
 347                        obj->flags |= flags;
 348                        ent[ents].item = obj;
 349                        ent[ents].name = name;
 350                        ents++;
 351                        continue;
 352                }
 353                if (obj->type == OBJ_BLOB) {
 354                        if (2 <= blobs)
 355                                die(_("more than two blobs given: '%s'"), name);
 356                        hashcpy(blob[blobs].sha1, obj->sha1);
 357                        blob[blobs].name = name;
 358                        blob[blobs].mode = list->mode;
 359                        blobs++;
 360                        continue;
 361
 362                }
 363                die(_("unhandled object '%s' given."), name);
 364        }
 365        if (rev.prune_data.nr) {
 366                if (!path)
 367                        path = rev.prune_data.items[0].match;
 368                paths += rev.prune_data.nr;
 369        }
 370
 371        /*
 372         * Now, do the arguments look reasonable?
 373         */
 374        if (!ents) {
 375                switch (blobs) {
 376                case 0:
 377                        result = builtin_diff_files(&rev, argc, argv);
 378                        break;
 379                case 1:
 380                        if (paths != 1)
 381                                usage(builtin_diff_usage);
 382                        result = builtin_diff_b_f(&rev, argc, argv, blob, path);
 383                        break;
 384                case 2:
 385                        if (paths)
 386                                usage(builtin_diff_usage);
 387                        result = builtin_diff_blobs(&rev, argc, argv, blob);
 388                        break;
 389                default:
 390                        usage(builtin_diff_usage);
 391                }
 392        }
 393        else if (blobs)
 394                usage(builtin_diff_usage);
 395        else if (ents == 1)
 396                result = builtin_diff_index(&rev, argc, argv);
 397        else if (ents == 2)
 398                result = builtin_diff_tree(&rev, argc, argv, ent);
 399        else if (ent[0].item->flags & UNINTERESTING) {
 400                /*
 401                 * diff A...B where there is at least one merge base
 402                 * between A and B.  We have ent[0] == merge-base,
 403                 * ent[ents-2] == A, and ent[ents-1] == B.  Show diff
 404                 * between the base and B.  Note that we pick one
 405                 * merge base at random if there are more than one.
 406                 */
 407                ent[1] = ent[ents-1];
 408                result = builtin_diff_tree(&rev, argc, argv, ent);
 409        } else
 410                result = builtin_diff_combined(&rev, argc, argv,
 411                                               ent, ents);
 412        result = diff_result_code(&rev.diffopt, result);
 413        if (1 < rev.diffopt.skip_stat_unmatch)
 414                refresh_index_quietly();
 415        return result;
 416}
 417
 418void setup_diff_pager(struct diff_options *opt)
 419{
 420        /*
 421         * If the user asked for our exit code, then either they want --quiet
 422         * or --exit-code. We should definitely not bother with a pager in the
 423         * former case, as we will generate no output. Since we still properly
 424         * report our exit code even when a pager is run, we _could_ run a
 425         * pager with --exit-code. But since we have not done so historically,
 426         * and because it is easy to find people oneline advising "git diff
 427         * --exit-code" in hooks and other scripts, we do not do so.
 428         */
 429        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
 430            check_pager_config("diff") != 0)
 431                setup_pager();
 432}