builtin / difftool.con commit Merge branch 'en/rebase-merge-on-sequencer' (8fe9c3f)
   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 "object-store.h"
  24#include "dir.h"
  25
  26static char *diff_gui_tool;
  27static int trust_exit_code;
  28
  29static const char *const builtin_difftool_usage[] = {
  30        N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
  31        NULL
  32};
  33
  34static int difftool_config(const char *var, const char *value, void *cb)
  35{
  36        if (!strcmp(var, "diff.guitool")) {
  37                diff_gui_tool = xstrdup(value);
  38                return 0;
  39        }
  40
  41        if (!strcmp(var, "difftool.trustexitcode")) {
  42                trust_exit_code = git_config_bool(var, value);
  43                return 0;
  44        }
  45
  46        return git_default_config(var, value, cb);
  47}
  48
  49static int print_tool_help(void)
  50{
  51        const char *argv[] = { "mergetool", "--tool-help=diff", NULL };
  52        return run_command_v_opt(argv, RUN_GIT_CMD);
  53}
  54
  55static int parse_index_info(char *p, int *mode1, int *mode2,
  56                            struct object_id *oid1, struct object_id *oid2,
  57                            char *status)
  58{
  59        if (*p != ':')
  60                return error("expected ':', got '%c'", *p);
  61        *mode1 = (int)strtol(p + 1, &p, 8);
  62        if (*p != ' ')
  63                return error("expected ' ', got '%c'", *p);
  64        *mode2 = (int)strtol(p + 1, &p, 8);
  65        if (*p != ' ')
  66                return error("expected ' ', got '%c'", *p);
  67        if (get_oid_hex(++p, oid1))
  68                return error("expected object ID, got '%s'", p + 1);
  69        p += GIT_SHA1_HEXSZ;
  70        if (*p != ' ')
  71                return error("expected ' ', got '%c'", *p);
  72        if (get_oid_hex(++p, oid2))
  73                return error("expected object ID, got '%s'", p + 1);
  74        p += GIT_SHA1_HEXSZ;
  75        if (*p != ' ')
  76                return error("expected ' ', got '%c'", *p);
  77        *status = *++p;
  78        if (!*status)
  79                return error("missing status");
  80        if (p[1] && !isdigit(p[1]))
  81                return error("unexpected trailer: '%s'", p + 1);
  82        return 0;
  83}
  84
  85/*
  86 * Remove any trailing slash from $workdir
  87 * before starting to avoid double slashes in symlink targets.
  88 */
  89static void add_path(struct strbuf *buf, size_t base_len, const char *path)
  90{
  91        strbuf_setlen(buf, base_len);
  92        if (buf->len && buf->buf[buf->len - 1] != '/')
  93                strbuf_addch(buf, '/');
  94        strbuf_addstr(buf, path);
  95}
  96
  97/*
  98 * Determine whether we can simply reuse the file in the worktree.
  99 */
 100static int use_wt_file(const char *workdir, const char *name,
 101                       struct object_id *oid)
 102{
 103        struct strbuf buf = STRBUF_INIT;
 104        struct stat st;
 105        int use = 0;
 106
 107        strbuf_addstr(&buf, workdir);
 108        add_path(&buf, buf.len, name);
 109
 110        if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
 111                struct object_id wt_oid;
 112                int fd = open(buf.buf, O_RDONLY);
 113
 114                if (fd >= 0 &&
 115                    !index_fd(&the_index, &wt_oid, fd, &st, OBJ_BLOB, name, 0)) {
 116                        if (is_null_oid(oid)) {
 117                                oidcpy(oid, &wt_oid);
 118                                use = 1;
 119                        } else if (oideq(oid, &wt_oid))
 120                                use = 1;
 121                }
 122        }
 123
 124        strbuf_release(&buf);
 125
 126        return use;
 127}
 128
 129struct working_tree_entry {
 130        struct hashmap_entry entry;
 131        char path[FLEX_ARRAY];
 132};
 133
 134static int working_tree_entry_cmp(const void *unused_cmp_data,
 135                                  const void *entry,
 136                                  const void *entry_or_key,
 137                                  const void *unused_keydata)
 138{
 139        const struct working_tree_entry *a = entry;
 140        const struct working_tree_entry *b = entry_or_key;
 141        return strcmp(a->path, b->path);
 142}
 143
 144/*
 145 * The `left` and `right` entries hold paths for the symlinks hashmap,
 146 * and a SHA-1 surrounded by brief text for submodules.
 147 */
 148struct pair_entry {
 149        struct hashmap_entry entry;
 150        char left[PATH_MAX], right[PATH_MAX];
 151        const char path[FLEX_ARRAY];
 152};
 153
 154static int pair_cmp(const void *unused_cmp_data,
 155                    const void *entry,
 156                    const void *entry_or_key,
 157                    const void *unused_keydata)
 158{
 159        const struct pair_entry *a = entry;
 160        const struct pair_entry *b = entry_or_key;
 161
 162        return strcmp(a->path, b->path);
 163}
 164
 165static void add_left_or_right(struct hashmap *map, const char *path,
 166                              const char *content, int is_right)
 167{
 168        struct pair_entry *e, *existing;
 169
 170        FLEX_ALLOC_STR(e, path, path);
 171        hashmap_entry_init(e, strhash(path));
 172        existing = hashmap_get(map, e, NULL);
 173        if (existing) {
 174                free(e);
 175                e = existing;
 176        } else {
 177                e->left[0] = e->right[0] = '\0';
 178                hashmap_add(map, e);
 179        }
 180        strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
 181}
 182
 183struct path_entry {
 184        struct hashmap_entry entry;
 185        char path[FLEX_ARRAY];
 186};
 187
 188static int path_entry_cmp(const void *unused_cmp_data,
 189                          const void *entry,
 190                          const void *entry_or_key,
 191                          const void *key)
 192{
 193        const struct path_entry *a = entry;
 194        const struct path_entry *b = entry_or_key;
 195
 196        return strcmp(a->path, key ? key : b->path);
 197}
 198
 199static void changed_files(struct hashmap *result, const char *index_path,
 200                          const char *workdir)
 201{
 202        struct child_process update_index = CHILD_PROCESS_INIT;
 203        struct child_process diff_files = CHILD_PROCESS_INIT;
 204        struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT;
 205        const char *git_dir = absolute_path(get_git_dir()), *env[] = {
 206                NULL, NULL
 207        };
 208        FILE *fp;
 209
 210        strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path);
 211        env[0] = index_env.buf;
 212
 213        argv_array_pushl(&update_index.args,
 214                         "--git-dir", git_dir, "--work-tree", workdir,
 215                         "update-index", "--really-refresh", "-q",
 216                         "--unmerged", NULL);
 217        update_index.no_stdin = 1;
 218        update_index.no_stdout = 1;
 219        update_index.no_stderr = 1;
 220        update_index.git_cmd = 1;
 221        update_index.use_shell = 0;
 222        update_index.clean_on_exit = 1;
 223        update_index.dir = workdir;
 224        update_index.env = env;
 225        /* Ignore any errors of update-index */
 226        run_command(&update_index);
 227
 228        argv_array_pushl(&diff_files.args,
 229                         "--git-dir", git_dir, "--work-tree", workdir,
 230                         "diff-files", "--name-only", "-z", NULL);
 231        diff_files.no_stdin = 1;
 232        diff_files.git_cmd = 1;
 233        diff_files.use_shell = 0;
 234        diff_files.clean_on_exit = 1;
 235        diff_files.out = -1;
 236        diff_files.dir = workdir;
 237        diff_files.env = env;
 238        if (start_command(&diff_files))
 239                die("could not obtain raw diff");
 240        fp = xfdopen(diff_files.out, "r");
 241        while (!strbuf_getline_nul(&buf, fp)) {
 242                struct path_entry *entry;
 243                FLEX_ALLOC_STR(entry, path, buf.buf);
 244                hashmap_entry_init(entry, strhash(buf.buf));
 245                hashmap_add(result, entry);
 246        }
 247        fclose(fp);
 248        if (finish_command(&diff_files))
 249                die("diff-files did not exit properly");
 250        strbuf_release(&index_env);
 251        strbuf_release(&buf);
 252}
 253
 254static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
 255{
 256        struct strbuf buf = STRBUF_INIT;
 257        strbuf_addstr(&buf, tmpdir);
 258        remove_dir_recursively(&buf, 0);
 259        if (exit_code)
 260                warning(_("failed: %d"), exit_code);
 261        exit(exit_code);
 262}
 263
 264static int ensure_leading_directories(char *path)
 265{
 266        switch (safe_create_leading_directories(path)) {
 267                case SCLD_OK:
 268                case SCLD_EXISTS:
 269                        return 0;
 270                default:
 271                        return error(_("could not create leading directories "
 272                                       "of '%s'"), path);
 273        }
 274}
 275
 276/*
 277 * Unconditional writing of a plain regular file is what
 278 * "git difftool --dir-diff" wants to do for symlinks.  We are preparing two
 279 * temporary directories to be fed to a Git-unaware tool that knows how to
 280 * show a diff of two directories (e.g. "diff -r A B").
 281 *
 282 * Because the tool is Git-unaware, if a symbolic link appears in either of
 283 * these temporary directories, it will try to dereference and show the
 284 * difference of the target of the symbolic link, which is not what we want,
 285 * as the goal of the dir-diff mode is to produce an output that is logically
 286 * equivalent to what "git diff" produces.
 287 *
 288 * Most importantly, we want to get textual comparison of the result of the
 289 * readlink(2).  get_symlink() provides that---it returns the contents of
 290 * the symlink that gets written to a regular file to force the external tool
 291 * to compare the readlink(2) result as text, even on a filesystem that is
 292 * capable of doing a symbolic link.
 293 */
 294static char *get_symlink(const struct object_id *oid, const char *path)
 295{
 296        char *data;
 297        if (is_null_oid(oid)) {
 298                /* The symlink is unknown to Git so read from the filesystem */
 299                struct strbuf link = STRBUF_INIT;
 300                if (has_symlinks) {
 301                        if (strbuf_readlink(&link, path, strlen(path)))
 302                                die(_("could not read symlink %s"), path);
 303                } else if (strbuf_read_file(&link, path, 128))
 304                        die(_("could not read symlink file %s"), path);
 305
 306                data = strbuf_detach(&link, NULL);
 307        } else {
 308                enum object_type type;
 309                unsigned long size;
 310                data = read_object_file(oid, &type, &size);
 311                if (!data)
 312                        die(_("could not read object %s for symlink %s"),
 313                                oid_to_hex(oid), path);
 314        }
 315
 316        return data;
 317}
 318
 319static int checkout_path(unsigned mode, struct object_id *oid,
 320                         const char *path, const struct checkout *state)
 321{
 322        struct cache_entry *ce;
 323        int ret;
 324
 325        ce = make_transient_cache_entry(mode, oid, path, 0);
 326        ret = checkout_entry(ce, state, NULL, NULL);
 327
 328        discard_cache_entry(ce);
 329        return ret;
 330}
 331
 332static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 333                        int argc, const char **argv)
 334{
 335        char tmpdir[PATH_MAX];
 336        struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
 337        struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
 338        struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
 339        struct strbuf wtdir = STRBUF_INIT;
 340        char *lbase_dir, *rbase_dir;
 341        size_t ldir_len, rdir_len, wtdir_len;
 342        const char *workdir, *tmp;
 343        int ret = 0, i;
 344        FILE *fp;
 345        struct hashmap working_tree_dups, submodules, symlinks2;
 346        struct hashmap_iter iter;
 347        struct pair_entry *entry;
 348        struct index_state wtindex;
 349        struct checkout lstate, rstate;
 350        int rc, flags = RUN_GIT_CMD, err = 0;
 351        struct child_process child = CHILD_PROCESS_INIT;
 352        const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
 353        struct hashmap wt_modified, tmp_modified;
 354        int indices_loaded = 0;
 355
 356        workdir = get_git_work_tree();
 357
 358        /* Setup temp directories */
 359        tmp = getenv("TMPDIR");
 360        xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
 361        if (!mkdtemp(tmpdir))
 362                return error("could not create '%s'", tmpdir);
 363        strbuf_addf(&ldir, "%s/left/", tmpdir);
 364        strbuf_addf(&rdir, "%s/right/", tmpdir);
 365        strbuf_addstr(&wtdir, workdir);
 366        if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
 367                strbuf_addch(&wtdir, '/');
 368        mkdir(ldir.buf, 0700);
 369        mkdir(rdir.buf, 0700);
 370
 371        memset(&wtindex, 0, sizeof(wtindex));
 372
 373        memset(&lstate, 0, sizeof(lstate));
 374        lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
 375        lstate.base_dir_len = ldir.len;
 376        lstate.force = 1;
 377        memset(&rstate, 0, sizeof(rstate));
 378        rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
 379        rstate.base_dir_len = rdir.len;
 380        rstate.force = 1;
 381
 382        ldir_len = ldir.len;
 383        rdir_len = rdir.len;
 384        wtdir_len = wtdir.len;
 385
 386        hashmap_init(&working_tree_dups, working_tree_entry_cmp, NULL, 0);
 387        hashmap_init(&submodules, pair_cmp, NULL, 0);
 388        hashmap_init(&symlinks2, pair_cmp, NULL, 0);
 389
 390        child.no_stdin = 1;
 391        child.git_cmd = 1;
 392        child.use_shell = 0;
 393        child.clean_on_exit = 1;
 394        child.dir = prefix;
 395        child.out = -1;
 396        argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
 397                         NULL);
 398        for (i = 0; i < argc; i++)
 399                argv_array_push(&child.args, argv[i]);
 400        if (start_command(&child))
 401                die("could not obtain raw diff");
 402        fp = xfdopen(child.out, "r");
 403
 404        /* Build index info for left and right sides of the diff */
 405        i = 0;
 406        while (!strbuf_getline_nul(&info, fp)) {
 407                int lmode, rmode;
 408                struct object_id loid, roid;
 409                char status;
 410                const char *src_path, *dst_path;
 411
 412                if (starts_with(info.buf, "::"))
 413                        die(N_("combined diff formats('-c' and '--cc') are "
 414                               "not supported in\n"
 415                               "directory diff mode('-d' and '--dir-diff')."));
 416
 417                if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
 418                                     &status))
 419                        break;
 420                if (strbuf_getline_nul(&lpath, fp))
 421                        break;
 422                src_path = lpath.buf;
 423
 424                i++;
 425                if (status != 'C' && status != 'R') {
 426                        dst_path = src_path;
 427                } else {
 428                        if (strbuf_getline_nul(&rpath, fp))
 429                                break;
 430                        dst_path = rpath.buf;
 431                }
 432
 433                if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
 434                        strbuf_reset(&buf);
 435                        strbuf_addf(&buf, "Subproject commit %s",
 436                                    oid_to_hex(&loid));
 437                        add_left_or_right(&submodules, src_path, buf.buf, 0);
 438                        strbuf_reset(&buf);
 439                        strbuf_addf(&buf, "Subproject commit %s",
 440                                    oid_to_hex(&roid));
 441                        if (oideq(&loid, &roid))
 442                                strbuf_addstr(&buf, "-dirty");
 443                        add_left_or_right(&submodules, dst_path, buf.buf, 1);
 444                        continue;
 445                }
 446
 447                if (S_ISLNK(lmode)) {
 448                        char *content = get_symlink(&loid, src_path);
 449                        add_left_or_right(&symlinks2, src_path, content, 0);
 450                        free(content);
 451                }
 452
 453                if (S_ISLNK(rmode)) {
 454                        char *content = get_symlink(&roid, dst_path);
 455                        add_left_or_right(&symlinks2, dst_path, content, 1);
 456                        free(content);
 457                }
 458
 459                if (lmode && status != 'C') {
 460                        if (checkout_path(lmode, &loid, src_path, &lstate)) {
 461                                ret = error("could not write '%s'", src_path);
 462                                goto finish;
 463                        }
 464                }
 465
 466                if (rmode && !S_ISLNK(rmode)) {
 467                        struct working_tree_entry *entry;
 468
 469                        /* Avoid duplicate working_tree entries */
 470                        FLEX_ALLOC_STR(entry, path, dst_path);
 471                        hashmap_entry_init(entry, strhash(dst_path));
 472                        if (hashmap_get(&working_tree_dups, entry, NULL)) {
 473                                free(entry);
 474                                continue;
 475                        }
 476                        hashmap_add(&working_tree_dups, entry);
 477
 478                        if (!use_wt_file(workdir, dst_path, &roid)) {
 479                                if (checkout_path(rmode, &roid, dst_path,
 480                                                  &rstate)) {
 481                                        ret = error("could not write '%s'",
 482                                                    dst_path);
 483                                        goto finish;
 484                                }
 485                        } else if (!is_null_oid(&roid)) {
 486                                /*
 487                                 * Changes in the working tree need special
 488                                 * treatment since they are not part of the
 489                                 * index.
 490                                 */
 491                                struct cache_entry *ce2 =
 492                                        make_cache_entry(&wtindex, rmode, &roid,
 493                                                         dst_path, 0, 0);
 494
 495                                add_index_entry(&wtindex, ce2,
 496                                                ADD_CACHE_JUST_APPEND);
 497
 498                                add_path(&rdir, rdir_len, dst_path);
 499                                if (ensure_leading_directories(rdir.buf)) {
 500                                        ret = error("could not create "
 501                                                    "directory for '%s'",
 502                                                    dst_path);
 503                                        goto finish;
 504                                }
 505                                add_path(&wtdir, wtdir_len, dst_path);
 506                                if (symlinks) {
 507                                        if (symlink(wtdir.buf, rdir.buf)) {
 508                                                ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
 509                                                goto finish;
 510                                        }
 511                                } else {
 512                                        struct stat st;
 513                                        if (stat(wtdir.buf, &st))
 514                                                st.st_mode = 0644;
 515                                        if (copy_file(rdir.buf, wtdir.buf,
 516                                                      st.st_mode)) {
 517                                                ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
 518                                                goto finish;
 519                                        }
 520                                }
 521                        }
 522                }
 523        }
 524
 525        fclose(fp);
 526        fp = NULL;
 527        if (finish_command(&child)) {
 528                ret = error("error occurred running diff --raw");
 529                goto finish;
 530        }
 531
 532        if (!i)
 533                goto finish;
 534
 535        /*
 536         * Changes to submodules require special treatment.This loop writes a
 537         * temporary file to both the left and right directories to show the
 538         * change in the recorded SHA1 for the submodule.
 539         */
 540        hashmap_iter_init(&submodules, &iter);
 541        while ((entry = hashmap_iter_next(&iter))) {
 542                if (*entry->left) {
 543                        add_path(&ldir, ldir_len, entry->path);
 544                        ensure_leading_directories(ldir.buf);
 545                        write_file(ldir.buf, "%s", entry->left);
 546                }
 547                if (*entry->right) {
 548                        add_path(&rdir, rdir_len, entry->path);
 549                        ensure_leading_directories(rdir.buf);
 550                        write_file(rdir.buf, "%s", entry->right);
 551                }
 552        }
 553
 554        /*
 555         * Symbolic links require special treatment.The standard "git diff"
 556         * shows only the link itself, not the contents of the link target.
 557         * This loop replicates that behavior.
 558         */
 559        hashmap_iter_init(&symlinks2, &iter);
 560        while ((entry = hashmap_iter_next(&iter))) {
 561                if (*entry->left) {
 562                        add_path(&ldir, ldir_len, entry->path);
 563                        ensure_leading_directories(ldir.buf);
 564                        write_file(ldir.buf, "%s", entry->left);
 565                }
 566                if (*entry->right) {
 567                        add_path(&rdir, rdir_len, entry->path);
 568                        ensure_leading_directories(rdir.buf);
 569                        write_file(rdir.buf, "%s", entry->right);
 570                }
 571        }
 572
 573        strbuf_release(&buf);
 574
 575        strbuf_setlen(&ldir, ldir_len);
 576        helper_argv[1] = ldir.buf;
 577        strbuf_setlen(&rdir, rdir_len);
 578        helper_argv[2] = rdir.buf;
 579
 580        if (extcmd) {
 581                helper_argv[0] = extcmd;
 582                flags = 0;
 583        } else
 584                setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
 585        rc = run_command_v_opt(helper_argv, flags);
 586
 587        /*
 588         * If the diff includes working copy files and those
 589         * files were modified during the diff, then the changes
 590         * should be copied back to the working tree.
 591         * Do not copy back files when symlinks are used and the
 592         * external tool did not replace the original link with a file.
 593         *
 594         * These hashes are loaded lazily since they aren't needed
 595         * in the common case of --symlinks and the difftool updating
 596         * files through the symlink.
 597         */
 598        hashmap_init(&wt_modified, path_entry_cmp, NULL, wtindex.cache_nr);
 599        hashmap_init(&tmp_modified, path_entry_cmp, NULL, wtindex.cache_nr);
 600
 601        for (i = 0; i < wtindex.cache_nr; i++) {
 602                struct hashmap_entry dummy;
 603                const char *name = wtindex.cache[i]->name;
 604                struct stat st;
 605
 606                add_path(&rdir, rdir_len, name);
 607                if (lstat(rdir.buf, &st))
 608                        continue;
 609
 610                if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
 611                        continue;
 612
 613                if (!indices_loaded) {
 614                        struct lock_file lock = LOCK_INIT;
 615                        strbuf_reset(&buf);
 616                        strbuf_addf(&buf, "%s/wtindex", tmpdir);
 617                        if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
 618                            write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
 619                                ret = error("could not write %s", buf.buf);
 620                                goto finish;
 621                        }
 622                        changed_files(&wt_modified, buf.buf, workdir);
 623                        strbuf_setlen(&rdir, rdir_len);
 624                        changed_files(&tmp_modified, buf.buf, rdir.buf);
 625                        add_path(&rdir, rdir_len, name);
 626                        indices_loaded = 1;
 627                }
 628
 629                hashmap_entry_init(&dummy, strhash(name));
 630                if (hashmap_get(&tmp_modified, &dummy, name)) {
 631                        add_path(&wtdir, wtdir_len, name);
 632                        if (hashmap_get(&wt_modified, &dummy, name)) {
 633                                warning(_("both files modified: '%s' and '%s'."),
 634                                        wtdir.buf, rdir.buf);
 635                                warning(_("working tree file has been left."));
 636                                warning("%s", "");
 637                                err = 1;
 638                        } else if (unlink(wtdir.buf) ||
 639                                   copy_file(wtdir.buf, rdir.buf, st.st_mode))
 640                                warning_errno(_("could not copy '%s' to '%s'"),
 641                                              rdir.buf, wtdir.buf);
 642                }
 643        }
 644
 645        if (err) {
 646                warning(_("temporary files exist in '%s'."), tmpdir);
 647                warning(_("you may want to cleanup or recover these."));
 648                exit(1);
 649        } else
 650                exit_cleanup(tmpdir, rc);
 651
 652finish:
 653        if (fp)
 654                fclose(fp);
 655
 656        free(lbase_dir);
 657        free(rbase_dir);
 658        strbuf_release(&ldir);
 659        strbuf_release(&rdir);
 660        strbuf_release(&wtdir);
 661        strbuf_release(&buf);
 662
 663        return ret;
 664}
 665
 666static int run_file_diff(int prompt, const char *prefix,
 667                         int argc, const char **argv)
 668{
 669        struct argv_array args = ARGV_ARRAY_INIT;
 670        const char *env[] = {
 671                "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
 672                NULL
 673        };
 674        int ret = 0, i;
 675
 676        if (prompt > 0)
 677                env[2] = "GIT_DIFFTOOL_PROMPT=true";
 678        else if (!prompt)
 679                env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
 680
 681
 682        argv_array_push(&args, "diff");
 683        for (i = 0; i < argc; i++)
 684                argv_array_push(&args, argv[i]);
 685        ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env);
 686        exit(ret);
 687}
 688
 689int cmd_difftool(int argc, const char **argv, const char *prefix)
 690{
 691        int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
 692            tool_help = 0;
 693        static char *difftool_cmd = NULL, *extcmd = NULL;
 694        struct option builtin_difftool_options[] = {
 695                OPT_BOOL('g', "gui", &use_gui_tool,
 696                         N_("use `diff.guitool` instead of `diff.tool`")),
 697                OPT_BOOL('d', "dir-diff", &dir_diff,
 698                         N_("perform a full-directory diff")),
 699                OPT_SET_INT_F('y', "no-prompt", &prompt,
 700                        N_("do not prompt before launching a diff tool"),
 701                        0, PARSE_OPT_NONEG),
 702                OPT_SET_INT_F(0, "prompt", &prompt, NULL,
 703                        1, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
 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}