Andrew's git - gitweb.git/blob - builtin/difftool.c

   1/*
   2 * "git difftool" builtin command
   3 *
   4 * This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
   5 * git-difftool--helper script.
   6 *
   7 * This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
   8 * The GIT_DIFF* variables are exported for use by git-difftool--helper.
   9 *
  10 * Any arguments that are unknown to this script are forwarded to 'git diff'.
  11 *
  12 * Copyright (C) 2016 Johannes Schindelin
  13 */
  14#include "cache.h"
  15#include "config.h"
  16#include "builtin.h"
  17#include "run-command.h"
  18#include "exec-cmd.h"
  19#include "parse-options.h"
  20#include "argv-array.h"
  21#include "strbuf.h"
  22#include "lockfile.h"
  23#include "dir.h"
  24
  25static char *diff_gui_tool;
  26static int trust_exit_code;
  27
  28static const char *const builtin_difftool_usage[] = {
  29        N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
  30        NULL
  31};
  32
  33static int difftool_config(const char *var, const char *value, void *cb)
  34{
  35        if (!strcmp(var, "diff.guitool")) {
  36                diff_gui_tool = xstrdup(value);
  37                return 0;
  38        }
  39
  40        if (!strcmp(var, "difftool.trustexitcode")) {
  41                trust_exit_code = git_config_bool(var, value);
  42                return 0;
  43        }
  44
  45        return git_default_config(var, value, cb);
  46}
  47
  48static int print_tool_help(void)
  49{
  50        const char *argv[] = { "mergetool", "--tool-help=diff", NULL };
  51        return run_command_v_opt(argv, RUN_GIT_CMD);
  52}
  53
  54static int parse_index_info(char *p, int *mode1, int *mode2,
  55                            struct object_id *oid1, struct object_id *oid2,
  56                            char *status)
  57{
  58        if (*p != ':')
  59                return error("expected ':', got '%c'", *p);
  60        *mode1 = (int)strtol(p + 1, &p, 8);
  61        if (*p != ' ')
  62                return error("expected ' ', got '%c'", *p);
  63        *mode2 = (int)strtol(p + 1, &p, 8);
  64        if (*p != ' ')
  65                return error("expected ' ', got '%c'", *p);
  66        if (get_oid_hex(++p, oid1))
  67                return error("expected object ID, got '%s'", p + 1);
  68        p += GIT_SHA1_HEXSZ;
  69        if (*p != ' ')
  70                return error("expected ' ', got '%c'", *p);
  71        if (get_oid_hex(++p, oid2))
  72                return error("expected object ID, got '%s'", p + 1);
  73        p += GIT_SHA1_HEXSZ;
  74        if (*p != ' ')
  75                return error("expected ' ', got '%c'", *p);
  76        *status = *++p;
  77        if (!*status)
  78                return error("missing status");
  79        if (p[1] && !isdigit(p[1]))
  80                return error("unexpected trailer: '%s'", p + 1);
  81        return 0;
  82}
  83
  84/*
  85 * Remove any trailing slash from $workdir
  86 * before starting to avoid double slashes in symlink targets.
  87 */
  88static void add_path(struct strbuf *buf, size_t base_len, const char *path)
  89{
  90        strbuf_setlen(buf, base_len);
  91        if (buf->len && buf->buf[buf->len - 1] != '/')
  92                strbuf_addch(buf, '/');
  93        strbuf_addstr(buf, path);
  94}
  95
  96/*
  97 * Determine whether we can simply reuse the file in the worktree.
  98 */
  99static int use_wt_file(const char *workdir, const char *name,
 100                       struct object_id *oid)
 101{
 102        struct strbuf buf = STRBUF_INIT;
 103        struct stat st;
 104        int use = 0;
 105
 106        strbuf_addstr(&buf, workdir);
 107        add_path(&buf, buf.len, name);
 108
 109        if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
 110                struct object_id wt_oid;
 111                int fd = open(buf.buf, O_RDONLY);
 112
 113                if (fd >= 0 &&
 114                    !index_fd(&wt_oid, fd, &st, OBJ_BLOB, name, 0)) {
 115                        if (is_null_oid(oid)) {
 116                                oidcpy(oid, &wt_oid);
 117                                use = 1;
 118                        } else if (!oidcmp(oid, &wt_oid))
 119                                use = 1;
 120                }
 121        }
 122
 123        strbuf_release(&buf);
 124
 125        return use;
 126}
 127
 128struct working_tree_entry {
 129        struct hashmap_entry entry;
 130        char path[FLEX_ARRAY];
 131};
 132
 133static int working_tree_entry_cmp(const void *unused_cmp_data,
 134                                  const void *entry,
 135                                  const void *entry_or_key,
 136                                  const void *unused_keydata)
 137{
 138        const struct working_tree_entry *a = entry;
 139        const struct working_tree_entry *b = entry_or_key;
 140        return strcmp(a->path, b->path);
 141}
 142
 143/*
 144 * The `left` and `right` entries hold paths for the symlinks hashmap,
 145 * and a SHA-1 surrounded by brief text for submodules.
 146 */
 147struct pair_entry {
 148        struct hashmap_entry entry;
 149        char left[PATH_MAX], right[PATH_MAX];
 150        const char path[FLEX_ARRAY];
 151};
 152
 153static int pair_cmp(const void *unused_cmp_data,
 154                    const void *entry,
 155                    const void *entry_or_key,
 156                    const void *unused_keydata)
 157{
 158        const struct pair_entry *a = entry;
 159        const struct pair_entry *b = entry_or_key;
 160
 161        return strcmp(a->path, b->path);
 162}
 163
 164static void add_left_or_right(struct hashmap *map, const char *path,
 165                              const char *content, int is_right)
 166{
 167        struct pair_entry *e, *existing;
 168
 169        FLEX_ALLOC_STR(e, path, path);
 170        hashmap_entry_init(e, strhash(path));
 171        existing = hashmap_get(map, e, NULL);
 172        if (existing) {
 173                free(e);
 174                e = existing;
 175        } else {
 176                e->left[0] = e->right[0] = '\0';
 177                hashmap_add(map, e);
 178        }
 179        strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
 180}
 181
 182struct path_entry {
 183        struct hashmap_entry entry;
 184        char path[FLEX_ARRAY];
 185};
 186
 187static int path_entry_cmp(const void *unused_cmp_data,
 188                          const void *entry,
 189                          const void *entry_or_key,
 190                          const void *key)
 191{
 192        const struct path_entry *a = entry;
 193        const struct path_entry *b = entry_or_key;
 194
 195        return strcmp(a->path, key ? key : b->path);
 196}
 197
 198static void changed_files(struct hashmap *result, const char *index_path,
 199                          const char *workdir)
 200{
 201        struct child_process update_index = CHILD_PROCESS_INIT;
 202        struct child_process diff_files = CHILD_PROCESS_INIT;
 203        struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT;
 204        const char *git_dir = absolute_path(get_git_dir()), *env[] = {
 205                NULL, NULL
 206        };
 207        FILE *fp;
 208
 209        strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path);
 210        env[0] = index_env.buf;
 211
 212        argv_array_pushl(&update_index.args,
 213                         "--git-dir", git_dir, "--work-tree", workdir,
 214                         "update-index", "--really-refresh", "-q",
 215                         "--unmerged", NULL);
 216        update_index.no_stdin = 1;
 217        update_index.no_stdout = 1;
 218        update_index.no_stderr = 1;
 219        update_index.git_cmd = 1;
 220        update_index.use_shell = 0;
 221        update_index.clean_on_exit = 1;
 222        update_index.dir = workdir;
 223        update_index.env = env;
 224        /* Ignore any errors of update-index */
 225        run_command(&update_index);
 226
 227        argv_array_pushl(&diff_files.args,
 228                         "--git-dir", git_dir, "--work-tree", workdir,
 229                         "diff-files", "--name-only", "-z", NULL);
 230        diff_files.no_stdin = 1;
 231        diff_files.git_cmd = 1;
 232        diff_files.use_shell = 0;
 233        diff_files.clean_on_exit = 1;
 234        diff_files.out = -1;
 235        diff_files.dir = workdir;
 236        diff_files.env = env;
 237        if (start_command(&diff_files))
 238                die("could not obtain raw diff");
 239        fp = xfdopen(diff_files.out, "r");
 240        while (!strbuf_getline_nul(&buf, fp)) {
 241                struct path_entry *entry;
 242                FLEX_ALLOC_STR(entry, path, buf.buf);
 243                hashmap_entry_init(entry, strhash(buf.buf));
 244                hashmap_add(result, entry);
 245        }
 246        fclose(fp);
 247        if (finish_command(&diff_files))
 248                die("diff-files did not exit properly");
 249        strbuf_release(&index_env);
 250        strbuf_release(&buf);
 251}
 252
 253static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
 254{
 255        struct strbuf buf = STRBUF_INIT;
 256        strbuf_addstr(&buf, tmpdir);
 257        remove_dir_recursively(&buf, 0);
 258        if (exit_code)
 259                warning(_("failed: %d"), exit_code);
 260        exit(exit_code);
 261}
 262
 263static int ensure_leading_directories(char *path)
 264{
 265        switch (safe_create_leading_directories(path)) {
 266                case SCLD_OK:
 267                case SCLD_EXISTS:
 268                        return 0;
 269                default:
 270                        return error(_("could not create leading directories "
 271                                       "of '%s'"), path);
 272        }
 273}
 274
 275/*
 276 * Unconditional writing of a plain regular file is what
 277 * "git difftool --dir-diff" wants to do for symlinks.  We are preparing two
 278 * temporary directories to be fed to a Git-unaware tool that knows how to
 279 * show a diff of two directories (e.g. "diff -r A B").
 280 *
 281 * Because the tool is Git-unaware, if a symbolic link appears in either of
 282 * these temporary directories, it will try to dereference and show the
 283 * difference of the target of the symbolic link, which is not what we want,
 284 * as the goal of the dir-diff mode is to produce an output that is logically
 285 * equivalent to what "git diff" produces.
 286 *
 287 * Most importantly, we want to get textual comparison of the result of the
 288 * readlink(2).  get_symlink() provides that---it returns the contents of
 289 * the symlink that gets written to a regular file to force the external tool
 290 * to compare the readlink(2) result as text, even on a filesystem that is
 291 * capable of doing a symbolic link.
 292 */
 293static char *get_symlink(const struct object_id *oid, const char *path)
 294{
 295        char *data;
 296        if (is_null_oid(oid)) {
 297                /* The symlink is unknown to Git so read from the filesystem */
 298                struct strbuf link = STRBUF_INIT;
 299                if (has_symlinks) {
 300                        if (strbuf_readlink(&link, path, strlen(path)))
 301                                die(_("could not read symlink %s"), path);
 302                } else if (strbuf_read_file(&link, path, 128))
 303                        die(_("could not read symlink file %s"), path);
 304
 305                data = strbuf_detach(&link, NULL);
 306        } else {
 307                enum object_type type;
 308                unsigned long size;
 309                data = read_object_file(oid, &type, &size);
 310                if (!data)
 311                        die(_("could not read object %s for symlink %s"),
 312                                oid_to_hex(oid), path);
 313        }
 314
 315        return data;
 316}
 317
 318static int checkout_path(unsigned mode, struct object_id *oid,
 319                         const char *path, const struct checkout *state)
 320{
 321        struct cache_entry *ce;
 322        int ret;
 323
 324        ce = make_cache_entry(mode, oid->hash, path, 0, 0);
 325        ret = checkout_entry(ce, state, NULL);
 326
 327        free(ce);
 328        return ret;
 329}
 330
 331static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 332                        int argc, const char **argv)
 333{
 334        char tmpdir[PATH_MAX];
 335        struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
 336        struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
 337        struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
 338        struct strbuf wtdir = STRBUF_INIT;
 339        char *lbase_dir, *rbase_dir;
 340        size_t ldir_len, rdir_len, wtdir_len;
 341        const char *workdir, *tmp;
 342        int ret = 0, i;
 343        FILE *fp;
 344        struct hashmap working_tree_dups, submodules, symlinks2;
 345        struct hashmap_iter iter;
 346        struct pair_entry *entry;
 347        struct index_state wtindex;
 348        struct checkout lstate, rstate;
 349        int rc, flags = RUN_GIT_CMD, err = 0;
 350        struct child_process child = CHILD_PROCESS_INIT;
 351        const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
 352        struct hashmap wt_modified, tmp_modified;
 353        int indices_loaded = 0;
 354
 355        workdir = get_git_work_tree();
 356
 357        /* Setup temp directories */
 358        tmp = getenv("TMPDIR");
 359        xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
 360        if (!mkdtemp(tmpdir))
 361                return error("could not create '%s'", tmpdir);
 362        strbuf_addf(&ldir, "%s/left/", tmpdir);
 363        strbuf_addf(&rdir, "%s/right/", tmpdir);
 364        strbuf_addstr(&wtdir, workdir);
 365        if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
 366                strbuf_addch(&wtdir, '/');
 367        mkdir(ldir.buf, 0700);
 368        mkdir(rdir.buf, 0700);
 369
 370        memset(&wtindex, 0, sizeof(wtindex));
 371
 372        memset(&lstate, 0, sizeof(lstate));
 373        lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
 374        lstate.base_dir_len = ldir.len;
 375        lstate.force = 1;
 376        memset(&rstate, 0, sizeof(rstate));
 377        rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
 378        rstate.base_dir_len = rdir.len;
 379        rstate.force = 1;
 380
 381        ldir_len = ldir.len;
 382        rdir_len = rdir.len;
 383        wtdir_len = wtdir.len;
 384
 385        hashmap_init(&working_tree_dups, working_tree_entry_cmp, NULL, 0);
 386        hashmap_init(&submodules, pair_cmp, NULL, 0);
 387        hashmap_init(&symlinks2, pair_cmp, NULL, 0);
 388
 389        child.no_stdin = 1;
 390        child.git_cmd = 1;
 391        child.use_shell = 0;
 392        child.clean_on_exit = 1;
 393        child.dir = prefix;
 394        child.out = -1;
 395        argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
 396                         NULL);
 397        for (i = 0; i < argc; i++)
 398                argv_array_push(&child.args, argv[i]);
 399        if (start_command(&child))
 400                die("could not obtain raw diff");
 401        fp = xfdopen(child.out, "r");
 402
 403        /* Build index info for left and right sides of the diff */
 404        i = 0;
 405        while (!strbuf_getline_nul(&info, fp)) {
 406                int lmode, rmode;
 407                struct object_id loid, roid;
 408                char status;
 409                const char *src_path, *dst_path;
 410
 411                if (starts_with(info.buf, "::"))
 412                        die(N_("combined diff formats('-c' and '--cc') are "
 413                               "not supported in\n"
 414                               "directory diff mode('-d' and '--dir-diff')."));
 415
 416                if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
 417                                     &status))
 418                        break;
 419                if (strbuf_getline_nul(&lpath, fp))
 420                        break;
 421                src_path = lpath.buf;
 422
 423                i++;
 424                if (status != 'C' && status != 'R') {
 425                        dst_path = src_path;
 426                } else {
 427                        if (strbuf_getline_nul(&rpath, fp))
 428                                break;
 429                        dst_path = rpath.buf;
 430                }
 431
 432                if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
 433                        strbuf_reset(&buf);
 434                        strbuf_addf(&buf, "Subproject commit %s",
 435                                    oid_to_hex(&loid));
 436                        add_left_or_right(&submodules, src_path, buf.buf, 0);
 437                        strbuf_reset(&buf);
 438                        strbuf_addf(&buf, "Subproject commit %s",
 439                                    oid_to_hex(&roid));
 440                        if (!oidcmp(&loid, &roid))
 441                                strbuf_addstr(&buf, "-dirty");
 442                        add_left_or_right(&submodules, dst_path, buf.buf, 1);
 443                        continue;
 444                }
 445
 446                if (S_ISLNK(lmode)) {
 447                        char *content = get_symlink(&loid, src_path);
 448                        add_left_or_right(&symlinks2, src_path, content, 0);
 449                        free(content);
 450                }
 451
 452                if (S_ISLNK(rmode)) {
 453                        char *content = get_symlink(&roid, dst_path);
 454                        add_left_or_right(&symlinks2, dst_path, content, 1);
 455                        free(content);
 456                }
 457
 458                if (lmode && status != 'C') {
 459                        if (checkout_path(lmode, &loid, src_path, &lstate)) {
 460                                ret = error("could not write '%s'", src_path);
 461                                goto finish;
 462                        }
 463                }
 464
 465                if (rmode && !S_ISLNK(rmode)) {
 466                        struct working_tree_entry *entry;
 467
 468                        /* Avoid duplicate working_tree entries */
 469                        FLEX_ALLOC_STR(entry, path, dst_path);
 470                        hashmap_entry_init(entry, strhash(dst_path));
 471                        if (hashmap_get(&working_tree_dups, entry, NULL)) {
 472                                free(entry);
 473                                continue;
 474                        }
 475                        hashmap_add(&working_tree_dups, entry);
 476
 477                        if (!use_wt_file(workdir, dst_path, &roid)) {
 478                                if (checkout_path(rmode, &roid, dst_path,
 479                                                  &rstate)) {
 480                                        ret = error("could not write '%s'",
 481                                                    dst_path);
 482                                        goto finish;
 483                                }
 484                        } else if (!is_null_oid(&roid)) {
 485                                /*
 486                                 * Changes in the working tree need special
 487                                 * treatment since they are not part of the
 488                                 * index.
 489                                 */
 490                                struct cache_entry *ce2 =
 491                                        make_cache_entry(rmode, roid.hash,
 492                                                         dst_path, 0, 0);
 493
 494                                add_index_entry(&wtindex, ce2,
 495                                                ADD_CACHE_JUST_APPEND);
 496
 497                                add_path(&rdir, rdir_len, dst_path);
 498                                if (ensure_leading_directories(rdir.buf)) {
 499                                        ret = error("could not create "
 500                                                    "directory for '%s'",
 501                                                    dst_path);
 502                                        goto finish;
 503                                }
 504                                add_path(&wtdir, wtdir_len, dst_path);
 505                                if (symlinks) {
 506                                        if (symlink(wtdir.buf, rdir.buf)) {
 507                                                ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
 508                                                goto finish;
 509                                        }
 510                                } else {
 511                                        struct stat st;
 512                                        if (stat(wtdir.buf, &st))
 513                                                st.st_mode = 0644;
 514                                        if (copy_file(rdir.buf, wtdir.buf,
 515                                                      st.st_mode)) {
 516                                                ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
 517                                                goto finish;
 518                                        }
 519                                }
 520                        }
 521                }
 522        }
 523
 524        fclose(fp);
 525        fp = NULL;
 526        if (finish_command(&child)) {
 527                ret = error("error occurred running diff --raw");
 528                goto finish;
 529        }
 530
 531        if (!i)
 532                goto finish;
 533
 534        /*
 535         * Changes to submodules require special treatment.This loop writes a
 536         * temporary file to both the left and right directories to show the
 537         * change in the recorded SHA1 for the submodule.
 538         */
 539        hashmap_iter_init(&submodules, &iter);
 540        while ((entry = hashmap_iter_next(&iter))) {
 541                if (*entry->left) {
 542                        add_path(&ldir, ldir_len, entry->path);
 543                        ensure_leading_directories(ldir.buf);
 544                        write_file(ldir.buf, "%s", entry->left);
 545                }
 546                if (*entry->right) {
 547                        add_path(&rdir, rdir_len, entry->path);
 548                        ensure_leading_directories(rdir.buf);
 549                        write_file(rdir.buf, "%s", entry->right);
 550                }
 551        }
 552
 553        /*
 554         * Symbolic links require special treatment.The standard "git diff"
 555         * shows only the link itself, not the contents of the link target.
 556         * This loop replicates that behavior.
 557         */
 558        hashmap_iter_init(&symlinks2, &iter);
 559        while ((entry = hashmap_iter_next(&iter))) {
 560                if (*entry->left) {
 561                        add_path(&ldir, ldir_len, entry->path);
 562                        ensure_leading_directories(ldir.buf);
 563                        write_file(ldir.buf, "%s", entry->left);
 564                }
 565                if (*entry->right) {
 566                        add_path(&rdir, rdir_len, entry->path);
 567                        ensure_leading_directories(rdir.buf);
 568                        write_file(rdir.buf, "%s", entry->right);
 569                }
 570        }
 571
 572        strbuf_release(&buf);
 573
 574        strbuf_setlen(&ldir, ldir_len);
 575        helper_argv[1] = ldir.buf;
 576        strbuf_setlen(&rdir, rdir_len);
 577        helper_argv[2] = rdir.buf;
 578
 579        if (extcmd) {
 580                helper_argv[0] = extcmd;
 581                flags = 0;
 582        } else
 583                setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
 584        rc = run_command_v_opt(helper_argv, flags);
 585
 586        /*
 587         * If the diff includes working copy files and those
 588         * files were modified during the diff, then the changes
 589         * should be copied back to the working tree.
 590         * Do not copy back files when symlinks are used and the
 591         * external tool did not replace the original link with a file.
 592         *
 593         * These hashes are loaded lazily since they aren't needed
 594         * in the common case of --symlinks and the difftool updating
 595         * files through the symlink.
 596         */
 597        hashmap_init(&wt_modified, path_entry_cmp, NULL, wtindex.cache_nr);
 598        hashmap_init(&tmp_modified, path_entry_cmp, NULL, wtindex.cache_nr);
 599
 600        for (i = 0; i < wtindex.cache_nr; i++) {
 601                struct hashmap_entry dummy;
 602                const char *name = wtindex.cache[i]->name;
 603                struct stat st;
 604
 605                add_path(&rdir, rdir_len, name);
 606                if (lstat(rdir.buf, &st))
 607                        continue;
 608
 609                if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
 610                        continue;
 611
 612                if (!indices_loaded) {
 613                        static struct lock_file lock;
 614                        strbuf_reset(&buf);
 615                        strbuf_addf(&buf, "%s/wtindex", tmpdir);
 616                        if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
 617                            write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
 618                                ret = error("could not write %s", buf.buf);
 619                                goto finish;
 620                        }
 621                        changed_files(&wt_modified, buf.buf, workdir);
 622                        strbuf_setlen(&rdir, rdir_len);
 623                        changed_files(&tmp_modified, buf.buf, rdir.buf);
 624                        add_path(&rdir, rdir_len, name);
 625                        indices_loaded = 1;
 626                }
 627
 628                hashmap_entry_init(&dummy, strhash(name));
 629                if (hashmap_get(&tmp_modified, &dummy, name)) {
 630                        add_path(&wtdir, wtdir_len, name);
 631                        if (hashmap_get(&wt_modified, &dummy, name)) {
 632                                warning(_("both files modified: '%s' and '%s'."),
 633                                        wtdir.buf, rdir.buf);
 634                                warning(_("working tree file has been left."));
 635                                warning("%s", "");
 636                                err = 1;
 637                        } else if (unlink(wtdir.buf) ||
 638                                   copy_file(wtdir.buf, rdir.buf, st.st_mode))
 639                                warning_errno(_("could not copy '%s' to '%s'"),
 640                                              rdir.buf, wtdir.buf);
 641                }
 642        }
 643
 644        if (err) {
 645                warning(_("temporary files exist in '%s'."), tmpdir);
 646                warning(_("you may want to cleanup or recover these."));
 647                exit(1);
 648        } else
 649                exit_cleanup(tmpdir, rc);
 650
 651finish:
 652        if (fp)
 653                fclose(fp);
 654
 655        free(lbase_dir);
 656        free(rbase_dir);
 657        strbuf_release(&ldir);
 658        strbuf_release(&rdir);
 659        strbuf_release(&wtdir);
 660        strbuf_release(&buf);
 661
 662        return ret;
 663}
 664
 665static int run_file_diff(int prompt, const char *prefix,
 666                         int argc, const char **argv)
 667{
 668        struct argv_array args = ARGV_ARRAY_INIT;
 669        const char *env[] = {
 670                "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
 671                NULL
 672        };
 673        int ret = 0, i;
 674
 675        if (prompt > 0)
 676                env[2] = "GIT_DIFFTOOL_PROMPT=true";
 677        else if (!prompt)
 678                env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
 679
 680
 681        argv_array_push(&args, "diff");
 682        for (i = 0; i < argc; i++)
 683                argv_array_push(&args, argv[i]);
 684        ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env);
 685        exit(ret);
 686}
 687
 688int cmd_difftool(int argc, const char **argv, const char *prefix)
 689{
 690        int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
 691            tool_help = 0;
 692        static char *difftool_cmd = NULL, *extcmd = NULL;
 693        struct option builtin_difftool_options[] = {
 694                OPT_BOOL('g', "gui", &use_gui_tool,
 695                         N_("use `diff.guitool` instead of `diff.tool`")),
 696                OPT_BOOL('d', "dir-diff", &dir_diff,
 697                         N_("perform a full-directory diff")),
 698                { OPTION_SET_INT, 'y', "no-prompt", &prompt, NULL,
 699                        N_("do not prompt before launching a diff tool"),
 700                        PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
 701                { OPTION_SET_INT, 0, "prompt", &prompt, NULL, NULL,
 702                        PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN,
 703                        NULL, 1 },
 704                OPT_BOOL(0, "symlinks", &symlinks,
 705                         N_("use symlinks in dir-diff mode")),
 706                OPT_STRING('t', "tool", &difftool_cmd, N_("<tool>"),
 707                           N_("use the specified diff tool")),
 708                OPT_BOOL(0, "tool-help", &tool_help,
 709                         N_("print a list of diff tools that may be used with "
 710                            "`--tool`")),
 711                OPT_BOOL(0, "trust-exit-code", &trust_exit_code,
 712                         N_("make 'git-difftool' exit when an invoked diff "
 713                            "tool returns a non - zero exit code")),
 714                OPT_STRING('x', "extcmd", &extcmd, N_("<command>"),
 715                           N_("specify a custom command for viewing diffs")),
 716                OPT_END()
 717        };
 718
 719        git_config(difftool_config, NULL);
 720        symlinks = has_symlinks;
 721
 722        argc = parse_options(argc, argv, prefix, builtin_difftool_options,
 723                             builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN |
 724                             PARSE_OPT_KEEP_DASHDASH);
 725
 726        if (tool_help)
 727                return print_tool_help();
 728
 729        /* NEEDSWORK: once we no longer spawn anything, remove this */
 730        setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
 731        setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
 732
 733        if (use_gui_tool && diff_gui_tool && *diff_gui_tool)
 734                setenv("GIT_DIFF_TOOL", diff_gui_tool, 1);
 735        else if (difftool_cmd) {
 736                if (*difftool_cmd)
 737                        setenv("GIT_DIFF_TOOL", difftool_cmd, 1);
 738                else
 739                        die(_("no <tool> given for --tool=<tool>"));
 740        }
 741
 742        if (extcmd) {
 743                if (*extcmd)
 744                        setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1);
 745                else
 746                        die(_("no <cmd> given for --extcmd=<cmd>"));
 747        }
 748
 749        setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
 750               trust_exit_code ? "true" : "false", 1);
 751
 752        /*
 753         * In directory diff mode, 'git-difftool--helper' is called once
 754         * to compare the a / b directories. In file diff mode, 'git diff'
 755         * will invoke a separate instance of 'git-difftool--helper' for
 756         * each file that changed.
 757         */
 758        if (dir_diff)
 759                return run_dir_diff(extcmd, symlinks, prefix, argc, argv);
 760        return run_file_diff(prompt, prefix, argc, argv);
 761}