builtin / difftool.con commit Merge branch 'jc/name-rev-lw-tag' into maint (e8d9d8b)
   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 "builtin.h"
  16#include "run-command.h"
  17#include "exec_cmd.h"
  18#include "parse-options.h"
  19#include "argv-array.h"
  20#include "strbuf.h"
  21#include "lockfile.h"
  22#include "dir.h"
  23
  24static char *diff_gui_tool;
  25static int trust_exit_code;
  26
  27static const char *const builtin_difftool_usage[] = {
  28        N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
  29        NULL
  30};
  31
  32static int difftool_config(const char *var, const char *value, void *cb)
  33{
  34        if (!strcmp(var, "diff.guitool")) {
  35                diff_gui_tool = xstrdup(value);
  36                return 0;
  37        }
  38
  39        if (!strcmp(var, "difftool.trustexitcode")) {
  40                trust_exit_code = git_config_bool(var, value);
  41                return 0;
  42        }
  43
  44        return git_default_config(var, value, cb);
  45}
  46
  47static int print_tool_help(void)
  48{
  49        const char *argv[] = { "mergetool", "--tool-help=diff", NULL };
  50        return run_command_v_opt(argv, RUN_GIT_CMD);
  51}
  52
  53static int parse_index_info(char *p, int *mode1, int *mode2,
  54                            struct object_id *oid1, struct object_id *oid2,
  55                            char *status)
  56{
  57        if (*p != ':')
  58                return error("expected ':', got '%c'", *p);
  59        *mode1 = (int)strtol(p + 1, &p, 8);
  60        if (*p != ' ')
  61                return error("expected ' ', got '%c'", *p);
  62        *mode2 = (int)strtol(p + 1, &p, 8);
  63        if (*p != ' ')
  64                return error("expected ' ', got '%c'", *p);
  65        if (get_oid_hex(++p, oid1))
  66                return error("expected object ID, got '%s'", p + 1);
  67        p += GIT_SHA1_HEXSZ;
  68        if (*p != ' ')
  69                return error("expected ' ', got '%c'", *p);
  70        if (get_oid_hex(++p, oid2))
  71                return error("expected object ID, got '%s'", p + 1);
  72        p += GIT_SHA1_HEXSZ;
  73        if (*p != ' ')
  74                return error("expected ' ', got '%c'", *p);
  75        *status = *++p;
  76        if (!*status)
  77                return error("missing status");
  78        if (p[1] && !isdigit(p[1]))
  79                return error("unexpected trailer: '%s'", p + 1);
  80        return 0;
  81}
  82
  83/*
  84 * Remove any trailing slash from $workdir
  85 * before starting to avoid double slashes in symlink targets.
  86 */
  87static void add_path(struct strbuf *buf, size_t base_len, const char *path)
  88{
  89        strbuf_setlen(buf, base_len);
  90        if (buf->len && buf->buf[buf->len - 1] != '/')
  91                strbuf_addch(buf, '/');
  92        strbuf_addstr(buf, path);
  93}
  94
  95/*
  96 * Determine whether we can simply reuse the file in the worktree.
  97 */
  98static int use_wt_file(const char *workdir, const char *name,
  99                       struct object_id *oid)
 100{
 101        struct strbuf buf = STRBUF_INIT;
 102        struct stat st;
 103        int use = 0;
 104
 105        strbuf_addstr(&buf, workdir);
 106        add_path(&buf, buf.len, name);
 107
 108        if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
 109                struct object_id wt_oid;
 110                int fd = open(buf.buf, O_RDONLY);
 111
 112                if (fd >= 0 &&
 113                    !index_fd(wt_oid.hash, fd, &st, OBJ_BLOB, name, 0)) {
 114                        if (is_null_oid(oid)) {
 115                                oidcpy(oid, &wt_oid);
 116                                use = 1;
 117                        } else if (!oidcmp(oid, &wt_oid))
 118                                use = 1;
 119                }
 120        }
 121
 122        strbuf_release(&buf);
 123
 124        return use;
 125}
 126
 127struct working_tree_entry {
 128        struct hashmap_entry entry;
 129        char path[FLEX_ARRAY];
 130};
 131
 132static int working_tree_entry_cmp(struct working_tree_entry *a,
 133                                  struct working_tree_entry *b, void *keydata)
 134{
 135        return strcmp(a->path, b->path);
 136}
 137
 138/*
 139 * The `left` and `right` entries hold paths for the symlinks hashmap,
 140 * and a SHA-1 surrounded by brief text for submodules.
 141 */
 142struct pair_entry {
 143        struct hashmap_entry entry;
 144        char left[PATH_MAX], right[PATH_MAX];
 145        const char path[FLEX_ARRAY];
 146};
 147
 148static int pair_cmp(struct pair_entry *a, struct pair_entry *b, void *keydata)
 149{
 150        return strcmp(a->path, b->path);
 151}
 152
 153static void add_left_or_right(struct hashmap *map, const char *path,
 154                              const char *content, int is_right)
 155{
 156        struct pair_entry *e, *existing;
 157
 158        FLEX_ALLOC_STR(e, path, path);
 159        hashmap_entry_init(e, strhash(path));
 160        existing = hashmap_get(map, e, NULL);
 161        if (existing) {
 162                free(e);
 163                e = existing;
 164        } else {
 165                e->left[0] = e->right[0] = '\0';
 166                hashmap_add(map, e);
 167        }
 168        strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
 169}
 170
 171struct path_entry {
 172        struct hashmap_entry entry;
 173        char path[FLEX_ARRAY];
 174};
 175
 176static int path_entry_cmp(struct path_entry *a, struct path_entry *b, void *key)
 177{
 178        return strcmp(a->path, key ? key : b->path);
 179}
 180
 181static void changed_files(struct hashmap *result, const char *index_path,
 182                          const char *workdir)
 183{
 184        struct child_process update_index = CHILD_PROCESS_INIT;
 185        struct child_process diff_files = CHILD_PROCESS_INIT;
 186        struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT;
 187        const char *git_dir = absolute_path(get_git_dir()), *env[] = {
 188                NULL, NULL
 189        };
 190        FILE *fp;
 191
 192        strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path);
 193        env[0] = index_env.buf;
 194
 195        argv_array_pushl(&update_index.args,
 196                         "--git-dir", git_dir, "--work-tree", workdir,
 197                         "update-index", "--really-refresh", "-q",
 198                         "--unmerged", NULL);
 199        update_index.no_stdin = 1;
 200        update_index.no_stdout = 1;
 201        update_index.no_stderr = 1;
 202        update_index.git_cmd = 1;
 203        update_index.use_shell = 0;
 204        update_index.clean_on_exit = 1;
 205        update_index.dir = workdir;
 206        update_index.env = env;
 207        /* Ignore any errors of update-index */
 208        run_command(&update_index);
 209
 210        argv_array_pushl(&diff_files.args,
 211                         "--git-dir", git_dir, "--work-tree", workdir,
 212                         "diff-files", "--name-only", "-z", NULL);
 213        diff_files.no_stdin = 1;
 214        diff_files.git_cmd = 1;
 215        diff_files.use_shell = 0;
 216        diff_files.clean_on_exit = 1;
 217        diff_files.out = -1;
 218        diff_files.dir = workdir;
 219        diff_files.env = env;
 220        if (start_command(&diff_files))
 221                die("could not obtain raw diff");
 222        fp = xfdopen(diff_files.out, "r");
 223        while (!strbuf_getline_nul(&buf, fp)) {
 224                struct path_entry *entry;
 225                FLEX_ALLOC_STR(entry, path, buf.buf);
 226                hashmap_entry_init(entry, strhash(buf.buf));
 227                hashmap_add(result, entry);
 228        }
 229        fclose(fp);
 230        if (finish_command(&diff_files))
 231                die("diff-files did not exit properly");
 232        strbuf_release(&index_env);
 233        strbuf_release(&buf);
 234}
 235
 236static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
 237{
 238        struct strbuf buf = STRBUF_INIT;
 239        strbuf_addstr(&buf, tmpdir);
 240        remove_dir_recursively(&buf, 0);
 241        if (exit_code)
 242                warning(_("failed: %d"), exit_code);
 243        exit(exit_code);
 244}
 245
 246static int ensure_leading_directories(char *path)
 247{
 248        switch (safe_create_leading_directories(path)) {
 249                case SCLD_OK:
 250                case SCLD_EXISTS:
 251                        return 0;
 252                default:
 253                        return error(_("could not create leading directories "
 254                                       "of '%s'"), path);
 255        }
 256}
 257
 258/*
 259 * Unconditional writing of a plain regular file is what
 260 * "git difftool --dir-diff" wants to do for symlinks.  We are preparing two
 261 * temporary directories to be fed to a Git-unaware tool that knows how to
 262 * show a diff of two directories (e.g. "diff -r A B").
 263 *
 264 * Because the tool is Git-unaware, if a symbolic link appears in either of
 265 * these temporary directories, it will try to dereference and show the
 266 * difference of the target of the symbolic link, which is not what we want,
 267 * as the goal of the dir-diff mode is to produce an output that is logically
 268 * equivalent to what "git diff" produces.
 269 *
 270 * Most importantly, we want to get textual comparison of the result of the
 271 * readlink(2).  get_symlink() provides that---it returns the contents of
 272 * the symlink that gets written to a regular file to force the external tool
 273 * to compare the readlink(2) result as text, even on a filesystem that is
 274 * capable of doing a symbolic link.
 275 */
 276static char *get_symlink(const struct object_id *oid, const char *path)
 277{
 278        char *data;
 279        if (is_null_oid(oid)) {
 280                /* The symlink is unknown to Git so read from the filesystem */
 281                struct strbuf link = STRBUF_INIT;
 282                if (has_symlinks) {
 283                        if (strbuf_readlink(&link, path, strlen(path)))
 284                                die(_("could not read symlink %s"), path);
 285                } else if (strbuf_read_file(&link, path, 128))
 286                        die(_("could not read symlink file %s"), path);
 287
 288                data = strbuf_detach(&link, NULL);
 289        } else {
 290                enum object_type type;
 291                unsigned long size;
 292                data = read_sha1_file(oid->hash, &type, &size);
 293                if (!data)
 294                        die(_("could not read object %s for symlink %s"),
 295                                oid_to_hex(oid), path);
 296        }
 297
 298        return data;
 299}
 300
 301static int checkout_path(unsigned mode, struct object_id *oid,
 302                         const char *path, const struct checkout *state)
 303{
 304        struct cache_entry *ce;
 305        int ret;
 306
 307        ce = make_cache_entry(mode, oid->hash, path, 0, 0);
 308        ret = checkout_entry(ce, state, NULL);
 309
 310        free(ce);
 311        return ret;
 312}
 313
 314static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 315                        int argc, const char **argv)
 316{
 317        char tmpdir[PATH_MAX];
 318        struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
 319        struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
 320        struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
 321        struct strbuf wtdir = STRBUF_INIT;
 322        char *lbase_dir, *rbase_dir;
 323        size_t ldir_len, rdir_len, wtdir_len;
 324        const char *workdir, *tmp;
 325        int ret = 0, i;
 326        FILE *fp;
 327        struct hashmap working_tree_dups, submodules, symlinks2;
 328        struct hashmap_iter iter;
 329        struct pair_entry *entry;
 330        struct index_state wtindex;
 331        struct checkout lstate, rstate;
 332        int rc, flags = RUN_GIT_CMD, err = 0;
 333        struct child_process child = CHILD_PROCESS_INIT;
 334        const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
 335        struct hashmap wt_modified, tmp_modified;
 336        int indices_loaded = 0;
 337
 338        workdir = get_git_work_tree();
 339
 340        /* Setup temp directories */
 341        tmp = getenv("TMPDIR");
 342        xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
 343        if (!mkdtemp(tmpdir))
 344                return error("could not create '%s'", tmpdir);
 345        strbuf_addf(&ldir, "%s/left/", tmpdir);
 346        strbuf_addf(&rdir, "%s/right/", tmpdir);
 347        strbuf_addstr(&wtdir, workdir);
 348        if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
 349                strbuf_addch(&wtdir, '/');
 350        mkdir(ldir.buf, 0700);
 351        mkdir(rdir.buf, 0700);
 352
 353        memset(&wtindex, 0, sizeof(wtindex));
 354
 355        memset(&lstate, 0, sizeof(lstate));
 356        lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
 357        lstate.base_dir_len = ldir.len;
 358        lstate.force = 1;
 359        memset(&rstate, 0, sizeof(rstate));
 360        rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
 361        rstate.base_dir_len = rdir.len;
 362        rstate.force = 1;
 363
 364        ldir_len = ldir.len;
 365        rdir_len = rdir.len;
 366        wtdir_len = wtdir.len;
 367
 368        hashmap_init(&working_tree_dups,
 369                     (hashmap_cmp_fn)working_tree_entry_cmp, 0);
 370        hashmap_init(&submodules, (hashmap_cmp_fn)pair_cmp, 0);
 371        hashmap_init(&symlinks2, (hashmap_cmp_fn)pair_cmp, 0);
 372
 373        child.no_stdin = 1;
 374        child.git_cmd = 1;
 375        child.use_shell = 0;
 376        child.clean_on_exit = 1;
 377        child.dir = prefix;
 378        child.out = -1;
 379        argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
 380                         NULL);
 381        for (i = 0; i < argc; i++)
 382                argv_array_push(&child.args, argv[i]);
 383        if (start_command(&child))
 384                die("could not obtain raw diff");
 385        fp = xfdopen(child.out, "r");
 386
 387        /* Build index info for left and right sides of the diff */
 388        i = 0;
 389        while (!strbuf_getline_nul(&info, fp)) {
 390                int lmode, rmode;
 391                struct object_id loid, roid;
 392                char status;
 393                const char *src_path, *dst_path;
 394
 395                if (starts_with(info.buf, "::"))
 396                        die(N_("combined diff formats('-c' and '--cc') are "
 397                               "not supported in\n"
 398                               "directory diff mode('-d' and '--dir-diff')."));
 399
 400                if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
 401                                     &status))
 402                        break;
 403                if (strbuf_getline_nul(&lpath, fp))
 404                        break;
 405                src_path = lpath.buf;
 406
 407                i++;
 408                if (status != 'C' && status != 'R') {
 409                        dst_path = src_path;
 410                } else {
 411                        if (strbuf_getline_nul(&rpath, fp))
 412                                break;
 413                        dst_path = rpath.buf;
 414                }
 415
 416                if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
 417                        strbuf_reset(&buf);
 418                        strbuf_addf(&buf, "Subproject commit %s",
 419                                    oid_to_hex(&loid));
 420                        add_left_or_right(&submodules, src_path, buf.buf, 0);
 421                        strbuf_reset(&buf);
 422                        strbuf_addf(&buf, "Subproject commit %s",
 423                                    oid_to_hex(&roid));
 424                        if (!oidcmp(&loid, &roid))
 425                                strbuf_addstr(&buf, "-dirty");
 426                        add_left_or_right(&submodules, dst_path, buf.buf, 1);
 427                        continue;
 428                }
 429
 430                if (S_ISLNK(lmode)) {
 431                        char *content = get_symlink(&loid, src_path);
 432                        add_left_or_right(&symlinks2, src_path, content, 0);
 433                        free(content);
 434                }
 435
 436                if (S_ISLNK(rmode)) {
 437                        char *content = get_symlink(&roid, dst_path);
 438                        add_left_or_right(&symlinks2, dst_path, content, 1);
 439                        free(content);
 440                }
 441
 442                if (lmode && status != 'C') {
 443                        if (checkout_path(lmode, &loid, src_path, &lstate)) {
 444                                ret = error("could not write '%s'", src_path);
 445                                goto finish;
 446                        }
 447                }
 448
 449                if (rmode && !S_ISLNK(rmode)) {
 450                        struct working_tree_entry *entry;
 451
 452                        /* Avoid duplicate working_tree entries */
 453                        FLEX_ALLOC_STR(entry, path, dst_path);
 454                        hashmap_entry_init(entry, strhash(dst_path));
 455                        if (hashmap_get(&working_tree_dups, entry, NULL)) {
 456                                free(entry);
 457                                continue;
 458                        }
 459                        hashmap_add(&working_tree_dups, entry);
 460
 461                        if (!use_wt_file(workdir, dst_path, &roid)) {
 462                                if (checkout_path(rmode, &roid, dst_path,
 463                                                  &rstate)) {
 464                                        ret = error("could not write '%s'",
 465                                                    dst_path);
 466                                        goto finish;
 467                                }
 468                        } else if (!is_null_oid(&roid)) {
 469                                /*
 470                                 * Changes in the working tree need special
 471                                 * treatment since they are not part of the
 472                                 * index.
 473                                 */
 474                                struct cache_entry *ce2 =
 475                                        make_cache_entry(rmode, roid.hash,
 476                                                         dst_path, 0, 0);
 477
 478                                add_index_entry(&wtindex, ce2,
 479                                                ADD_CACHE_JUST_APPEND);
 480
 481                                add_path(&rdir, rdir_len, dst_path);
 482                                if (ensure_leading_directories(rdir.buf)) {
 483                                        ret = error("could not create "
 484                                                    "directory for '%s'",
 485                                                    dst_path);
 486                                        goto finish;
 487                                }
 488                                add_path(&wtdir, wtdir_len, dst_path);
 489                                if (symlinks) {
 490                                        if (symlink(wtdir.buf, rdir.buf)) {
 491                                                ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
 492                                                goto finish;
 493                                        }
 494                                } else {
 495                                        struct stat st;
 496                                        if (stat(wtdir.buf, &st))
 497                                                st.st_mode = 0644;
 498                                        if (copy_file(rdir.buf, wtdir.buf,
 499                                                      st.st_mode)) {
 500                                                ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
 501                                                goto finish;
 502                                        }
 503                                }
 504                        }
 505                }
 506        }
 507
 508        fclose(fp);
 509        fp = NULL;
 510        if (finish_command(&child)) {
 511                ret = error("error occurred running diff --raw");
 512                goto finish;
 513        }
 514
 515        if (!i)
 516                goto finish;
 517
 518        /*
 519         * Changes to submodules require special treatment.This loop writes a
 520         * temporary file to both the left and right directories to show the
 521         * change in the recorded SHA1 for the submodule.
 522         */
 523        hashmap_iter_init(&submodules, &iter);
 524        while ((entry = hashmap_iter_next(&iter))) {
 525                if (*entry->left) {
 526                        add_path(&ldir, ldir_len, entry->path);
 527                        ensure_leading_directories(ldir.buf);
 528                        write_file(ldir.buf, "%s", entry->left);
 529                }
 530                if (*entry->right) {
 531                        add_path(&rdir, rdir_len, entry->path);
 532                        ensure_leading_directories(rdir.buf);
 533                        write_file(rdir.buf, "%s", entry->right);
 534                }
 535        }
 536
 537        /*
 538         * Symbolic links require special treatment.The standard "git diff"
 539         * shows only the link itself, not the contents of the link target.
 540         * This loop replicates that behavior.
 541         */
 542        hashmap_iter_init(&symlinks2, &iter);
 543        while ((entry = hashmap_iter_next(&iter))) {
 544                if (*entry->left) {
 545                        add_path(&ldir, ldir_len, entry->path);
 546                        ensure_leading_directories(ldir.buf);
 547                        write_file(ldir.buf, "%s", entry->left);
 548                }
 549                if (*entry->right) {
 550                        add_path(&rdir, rdir_len, entry->path);
 551                        ensure_leading_directories(rdir.buf);
 552                        write_file(rdir.buf, "%s", entry->right);
 553                }
 554        }
 555
 556        strbuf_release(&buf);
 557
 558        strbuf_setlen(&ldir, ldir_len);
 559        helper_argv[1] = ldir.buf;
 560        strbuf_setlen(&rdir, rdir_len);
 561        helper_argv[2] = rdir.buf;
 562
 563        if (extcmd) {
 564                helper_argv[0] = extcmd;
 565                flags = 0;
 566        } else
 567                setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
 568        rc = run_command_v_opt(helper_argv, flags);
 569
 570        /*
 571         * If the diff includes working copy files and those
 572         * files were modified during the diff, then the changes
 573         * should be copied back to the working tree.
 574         * Do not copy back files when symlinks are used and the
 575         * external tool did not replace the original link with a file.
 576         *
 577         * These hashes are loaded lazily since they aren't needed
 578         * in the common case of --symlinks and the difftool updating
 579         * files through the symlink.
 580         */
 581        hashmap_init(&wt_modified, (hashmap_cmp_fn)path_entry_cmp,
 582                     wtindex.cache_nr);
 583        hashmap_init(&tmp_modified, (hashmap_cmp_fn)path_entry_cmp,
 584                     wtindex.cache_nr);
 585
 586        for (i = 0; i < wtindex.cache_nr; i++) {
 587                struct hashmap_entry dummy;
 588                const char *name = wtindex.cache[i]->name;
 589                struct stat st;
 590
 591                add_path(&rdir, rdir_len, name);
 592                if (lstat(rdir.buf, &st))
 593                        continue;
 594
 595                if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
 596                        continue;
 597
 598                if (!indices_loaded) {
 599                        static struct lock_file lock;
 600                        strbuf_reset(&buf);
 601                        strbuf_addf(&buf, "%s/wtindex", tmpdir);
 602                        if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
 603                            write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
 604                                ret = error("could not write %s", buf.buf);
 605                                rollback_lock_file(&lock);
 606                                goto finish;
 607                        }
 608                        changed_files(&wt_modified, buf.buf, workdir);
 609                        strbuf_setlen(&rdir, rdir_len);
 610                        changed_files(&tmp_modified, buf.buf, rdir.buf);
 611                        add_path(&rdir, rdir_len, name);
 612                        indices_loaded = 1;
 613                }
 614
 615                hashmap_entry_init(&dummy, strhash(name));
 616                if (hashmap_get(&tmp_modified, &dummy, name)) {
 617                        add_path(&wtdir, wtdir_len, name);
 618                        if (hashmap_get(&wt_modified, &dummy, name)) {
 619                                warning(_("both files modified: '%s' and '%s'."),
 620                                        wtdir.buf, rdir.buf);
 621                                warning(_("working tree file has been left."));
 622                                warning("%s", "");
 623                                err = 1;
 624                        } else if (unlink(wtdir.buf) ||
 625                                   copy_file(wtdir.buf, rdir.buf, st.st_mode))
 626                                warning_errno(_("could not copy '%s' to '%s'"),
 627                                              rdir.buf, wtdir.buf);
 628                }
 629        }
 630
 631        if (err) {
 632                warning(_("temporary files exist in '%s'."), tmpdir);
 633                warning(_("you may want to cleanup or recover these."));
 634                exit(1);
 635        } else
 636                exit_cleanup(tmpdir, rc);
 637
 638finish:
 639        if (fp)
 640                fclose(fp);
 641
 642        free(lbase_dir);
 643        free(rbase_dir);
 644        strbuf_release(&ldir);
 645        strbuf_release(&rdir);
 646        strbuf_release(&wtdir);
 647        strbuf_release(&buf);
 648
 649        return ret;
 650}
 651
 652static int run_file_diff(int prompt, const char *prefix,
 653                         int argc, const char **argv)
 654{
 655        struct argv_array args = ARGV_ARRAY_INIT;
 656        const char *env[] = {
 657                "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
 658                NULL
 659        };
 660        int ret = 0, i;
 661
 662        if (prompt > 0)
 663                env[2] = "GIT_DIFFTOOL_PROMPT=true";
 664        else if (!prompt)
 665                env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
 666
 667
 668        argv_array_push(&args, "diff");
 669        for (i = 0; i < argc; i++)
 670                argv_array_push(&args, argv[i]);
 671        ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env);
 672        exit(ret);
 673}
 674
 675int cmd_difftool(int argc, const char **argv, const char *prefix)
 676{
 677        int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
 678            tool_help = 0;
 679        static char *difftool_cmd = NULL, *extcmd = NULL;
 680        struct option builtin_difftool_options[] = {
 681                OPT_BOOL('g', "gui", &use_gui_tool,
 682                         N_("use `diff.guitool` instead of `diff.tool`")),
 683                OPT_BOOL('d', "dir-diff", &dir_diff,
 684                         N_("perform a full-directory diff")),
 685                { OPTION_SET_INT, 'y', "no-prompt", &prompt, NULL,
 686                        N_("do not prompt before launching a diff tool"),
 687                        PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
 688                { OPTION_SET_INT, 0, "prompt", &prompt, NULL, NULL,
 689                        PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN,
 690                        NULL, 1 },
 691                OPT_BOOL(0, "symlinks", &symlinks,
 692                         N_("use symlinks in dir-diff mode")),
 693                OPT_STRING('t', "tool", &difftool_cmd, N_("<tool>"),
 694                           N_("use the specified diff tool")),
 695                OPT_BOOL(0, "tool-help", &tool_help,
 696                         N_("print a list of diff tools that may be used with "
 697                            "`--tool`")),
 698                OPT_BOOL(0, "trust-exit-code", &trust_exit_code,
 699                         N_("make 'git-difftool' exit when an invoked diff "
 700                            "tool returns a non - zero exit code")),
 701                OPT_STRING('x', "extcmd", &extcmd, N_("<command>"),
 702                           N_("specify a custom command for viewing diffs")),
 703                OPT_END()
 704        };
 705
 706        git_config(difftool_config, NULL);
 707        symlinks = has_symlinks;
 708
 709        argc = parse_options(argc, argv, prefix, builtin_difftool_options,
 710                             builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN |
 711                             PARSE_OPT_KEEP_DASHDASH);
 712
 713        if (tool_help)
 714                return print_tool_help();
 715
 716        /* NEEDSWORK: once we no longer spawn anything, remove this */
 717        setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
 718        setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
 719
 720        if (use_gui_tool && diff_gui_tool && *diff_gui_tool)
 721                setenv("GIT_DIFF_TOOL", diff_gui_tool, 1);
 722        else if (difftool_cmd) {
 723                if (*difftool_cmd)
 724                        setenv("GIT_DIFF_TOOL", difftool_cmd, 1);
 725                else
 726                        die(_("no <tool> given for --tool=<tool>"));
 727        }
 728
 729        if (extcmd) {
 730                if (*extcmd)
 731                        setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1);
 732                else
 733                        die(_("no <cmd> given for --extcmd=<cmd>"));
 734        }
 735
 736        setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
 737               trust_exit_code ? "true" : "false", 1);
 738
 739        /*
 740         * In directory diff mode, 'git-difftool--helper' is called once
 741         * to compare the a / b directories. In file diff mode, 'git diff'
 742         * will invoke a separate instance of 'git-difftool--helper' for
 743         * each file that changed.
 744         */
 745        if (dir_diff)
 746                return run_dir_diff(extcmd, symlinks, prefix, argc, argv);
 747        return run_file_diff(prompt, prefix, argc, argv);
 748}