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-rw-r--r--builtin/difftool.c692
1 files changed, 692 insertions, 0 deletions
diff --git a/builtin/difftool.c b/builtin/difftool.c
new file mode 100644
index 0000000000..d13350ce83
--- /dev/null
+++ b/builtin/difftool.c
@@ -0,0 +1,692 @@
+/*
+ * "git difftool" builtin command
+ *
+ * This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
+ * git-difftool--helper script.
+ *
+ * This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
+ * The GIT_DIFF* variables are exported for use by git-difftool--helper.
+ *
+ * Any arguments that are unknown to this script are forwarded to 'git diff'.
+ *
+ * Copyright (C) 2016 Johannes Schindelin
+ */
+#include "cache.h"
+#include "builtin.h"
+#include "run-command.h"
+#include "exec_cmd.h"
+#include "parse-options.h"
+#include "argv-array.h"
+#include "strbuf.h"
+#include "lockfile.h"
+#include "dir.h"
+
+static char *diff_gui_tool;
+static int trust_exit_code;
+
+static const char *const builtin_difftool_usage[] = {
+ N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
+ NULL
+};
+
+static int difftool_config(const char *var, const char *value, void *cb)
+{
+ if (!strcmp(var, "diff.guitool")) {
+ diff_gui_tool = xstrdup(value);
+ return 0;
+ }
+
+ if (!strcmp(var, "difftool.trustexitcode")) {
+ trust_exit_code = git_config_bool(var, value);
+ return 0;
+ }
+
+ return git_default_config(var, value, cb);
+}
+
+static int print_tool_help(void)
+{
+ const char *argv[] = { "mergetool", "--tool-help=diff", NULL };
+ return run_command_v_opt(argv, RUN_GIT_CMD);
+}
+
+static int parse_index_info(char *p, int *mode1, int *mode2,
+ struct object_id *oid1, struct object_id *oid2,
+ char *status)
+{
+ if (*p != ':')
+ return error("expected ':', got '%c'", *p);
+ *mode1 = (int)strtol(p + 1, &p, 8);
+ if (*p != ' ')
+ return error("expected ' ', got '%c'", *p);
+ *mode2 = (int)strtol(p + 1, &p, 8);
+ if (*p != ' ')
+ return error("expected ' ', got '%c'", *p);
+ if (get_oid_hex(++p, oid1))
+ return error("expected object ID, got '%s'", p + 1);
+ p += GIT_SHA1_HEXSZ;
+ if (*p != ' ')
+ return error("expected ' ', got '%c'", *p);
+ if (get_oid_hex(++p, oid2))
+ return error("expected object ID, got '%s'", p + 1);
+ p += GIT_SHA1_HEXSZ;
+ if (*p != ' ')
+ return error("expected ' ', got '%c'", *p);
+ *status = *++p;
+ if (!*status)
+ return error("missing status");
+ if (p[1] && !isdigit(p[1]))
+ return error("unexpected trailer: '%s'", p + 1);
+ return 0;
+}
+
+/*
+ * Remove any trailing slash from $workdir
+ * before starting to avoid double slashes in symlink targets.
+ */
+static void add_path(struct strbuf *buf, size_t base_len, const char *path)
+{
+ strbuf_setlen(buf, base_len);
+ if (buf->len && buf->buf[buf->len - 1] != '/')
+ strbuf_addch(buf, '/');
+ strbuf_addstr(buf, path);
+}
+
+/*
+ * Determine whether we can simply reuse the file in the worktree.
+ */
+static int use_wt_file(const char *workdir, const char *name,
+ struct object_id *oid)
+{
+ struct strbuf buf = STRBUF_INIT;
+ struct stat st;
+ int use = 0;
+
+ strbuf_addstr(&buf, workdir);
+ add_path(&buf, buf.len, name);
+
+ if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
+ struct object_id wt_oid;
+ int fd = open(buf.buf, O_RDONLY);
+
+ if (fd >= 0 &&
+ !index_fd(wt_oid.hash, fd, &st, OBJ_BLOB, name, 0)) {
+ if (is_null_oid(oid)) {
+ oidcpy(oid, &wt_oid);
+ use = 1;
+ } else if (!oidcmp(oid, &wt_oid))
+ use = 1;
+ }
+ }
+
+ strbuf_release(&buf);
+
+ return use;
+}
+
+struct working_tree_entry {
+ struct hashmap_entry entry;
+ char path[FLEX_ARRAY];
+};
+
+static int working_tree_entry_cmp(struct working_tree_entry *a,
+ struct working_tree_entry *b, void *keydata)
+{
+ return strcmp(a->path, b->path);
+}
+
+/*
+ * The `left` and `right` entries hold paths for the symlinks hashmap,
+ * and a SHA-1 surrounded by brief text for submodules.
+ */
+struct pair_entry {
+ struct hashmap_entry entry;
+ char left[PATH_MAX], right[PATH_MAX];
+ const char path[FLEX_ARRAY];
+};
+
+static int pair_cmp(struct pair_entry *a, struct pair_entry *b, void *keydata)
+{
+ return strcmp(a->path, b->path);
+}
+
+static void add_left_or_right(struct hashmap *map, const char *path,
+ const char *content, int is_right)
+{
+ struct pair_entry *e, *existing;
+
+ FLEX_ALLOC_STR(e, path, path);
+ hashmap_entry_init(e, strhash(path));
+ existing = hashmap_get(map, e, NULL);
+ if (existing) {
+ free(e);
+ e = existing;
+ } else {
+ e->left[0] = e->right[0] = '\0';
+ hashmap_add(map, e);
+ }
+ strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
+}
+
+struct path_entry {
+ struct hashmap_entry entry;
+ char path[FLEX_ARRAY];
+};
+
+static int path_entry_cmp(struct path_entry *a, struct path_entry *b, void *key)
+{
+ return strcmp(a->path, key ? key : b->path);
+}
+
+static void changed_files(struct hashmap *result, const char *index_path,
+ const char *workdir)
+{
+ struct child_process update_index = CHILD_PROCESS_INIT;
+ struct child_process diff_files = CHILD_PROCESS_INIT;
+ struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT;
+ const char *git_dir = absolute_path(get_git_dir()), *env[] = {
+ NULL, NULL
+ };
+ FILE *fp;
+
+ strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path);
+ env[0] = index_env.buf;
+
+ argv_array_pushl(&update_index.args,
+ "--git-dir", git_dir, "--work-tree", workdir,
+ "update-index", "--really-refresh", "-q",
+ "--unmerged", NULL);
+ update_index.no_stdin = 1;
+ update_index.no_stdout = 1;
+ update_index.no_stderr = 1;
+ update_index.git_cmd = 1;
+ update_index.use_shell = 0;
+ update_index.clean_on_exit = 1;
+ update_index.dir = workdir;
+ update_index.env = env;
+ /* Ignore any errors of update-index */
+ run_command(&update_index);
+
+ argv_array_pushl(&diff_files.args,
+ "--git-dir", git_dir, "--work-tree", workdir,
+ "diff-files", "--name-only", "-z", NULL);
+ diff_files.no_stdin = 1;
+ diff_files.git_cmd = 1;
+ diff_files.use_shell = 0;
+ diff_files.clean_on_exit = 1;
+ diff_files.out = -1;
+ diff_files.dir = workdir;
+ diff_files.env = env;
+ if (start_command(&diff_files))
+ die("could not obtain raw diff");
+ fp = xfdopen(diff_files.out, "r");
+ while (!strbuf_getline_nul(&buf, fp)) {
+ struct path_entry *entry;
+ FLEX_ALLOC_STR(entry, path, buf.buf);
+ hashmap_entry_init(entry, strhash(buf.buf));
+ hashmap_add(result, entry);
+ }
+ if (finish_command(&diff_files))
+ die("diff-files did not exit properly");
+ strbuf_release(&index_env);
+ strbuf_release(&buf);
+}
+
+static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
+{
+ struct strbuf buf = STRBUF_INIT;
+ strbuf_addstr(&buf, tmpdir);
+ remove_dir_recursively(&buf, 0);
+ if (exit_code)
+ warning(_("failed: %d"), exit_code);
+ exit(exit_code);
+}
+
+static int ensure_leading_directories(char *path)
+{
+ switch (safe_create_leading_directories(path)) {
+ case SCLD_OK:
+ case SCLD_EXISTS:
+ return 0;
+ default:
+ return error(_("could not create leading directories "
+ "of '%s'"), path);
+ }
+}
+
+static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
+ int argc, const char **argv)
+{
+ char tmpdir[PATH_MAX];
+ struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
+ struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
+ struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
+ struct strbuf wtdir = STRBUF_INIT;
+ size_t ldir_len, rdir_len, wtdir_len;
+ struct cache_entry *ce = xcalloc(1, sizeof(ce) + PATH_MAX + 1);
+ const char *workdir, *tmp;
+ int ret = 0, i;
+ FILE *fp;
+ struct hashmap working_tree_dups, submodules, symlinks2;
+ struct hashmap_iter iter;
+ struct pair_entry *entry;
+ enum object_type type;
+ unsigned long size;
+ struct index_state wtindex;
+ struct checkout lstate, rstate;
+ int rc, flags = RUN_GIT_CMD, err = 0;
+ struct child_process child = CHILD_PROCESS_INIT;
+ const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
+ struct hashmap wt_modified, tmp_modified;
+ int indices_loaded = 0;
+
+ workdir = get_git_work_tree();
+
+ /* Setup temp directories */
+ tmp = getenv("TMPDIR");
+ xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
+ if (!mkdtemp(tmpdir))
+ return error("could not create '%s'", tmpdir);
+ strbuf_addf(&ldir, "%s/left/", tmpdir);
+ strbuf_addf(&rdir, "%s/right/", tmpdir);
+ strbuf_addstr(&wtdir, workdir);
+ if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
+ strbuf_addch(&wtdir, '/');
+ mkdir(ldir.buf, 0700);
+ mkdir(rdir.buf, 0700);
+
+ memset(&wtindex, 0, sizeof(wtindex));
+
+ memset(&lstate, 0, sizeof(lstate));
+ lstate.base_dir = ldir.buf;
+ lstate.base_dir_len = ldir.len;
+ lstate.force = 1;
+ memset(&rstate, 0, sizeof(rstate));
+ rstate.base_dir = rdir.buf;
+ rstate.base_dir_len = rdir.len;
+ rstate.force = 1;
+
+ ldir_len = ldir.len;
+ rdir_len = rdir.len;
+ wtdir_len = wtdir.len;
+
+ hashmap_init(&working_tree_dups,
+ (hashmap_cmp_fn)working_tree_entry_cmp, 0);
+ hashmap_init(&submodules, (hashmap_cmp_fn)pair_cmp, 0);
+ hashmap_init(&symlinks2, (hashmap_cmp_fn)pair_cmp, 0);
+
+ child.no_stdin = 1;
+ child.git_cmd = 1;
+ child.use_shell = 0;
+ child.clean_on_exit = 1;
+ child.dir = prefix;
+ child.out = -1;
+ argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
+ NULL);
+ for (i = 0; i < argc; i++)
+ argv_array_push(&child.args, argv[i]);
+ if (start_command(&child))
+ die("could not obtain raw diff");
+ fp = xfdopen(child.out, "r");
+
+ /* Build index info for left and right sides of the diff */
+ i = 0;
+ while (!strbuf_getline_nul(&info, fp)) {
+ int lmode, rmode;
+ struct object_id loid, roid;
+ char status;
+ const char *src_path, *dst_path;
+ size_t src_path_len, dst_path_len;
+
+ if (starts_with(info.buf, "::"))
+ die(N_("combined diff formats('-c' and '--cc') are "
+ "not supported in\n"
+ "directory diff mode('-d' and '--dir-diff')."));
+
+ if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
+ &status))
+ break;
+ if (strbuf_getline_nul(&lpath, fp))
+ break;
+ src_path = lpath.buf;
+ src_path_len = lpath.len;
+
+ i++;
+ if (status != 'C' && status != 'R') {
+ dst_path = src_path;
+ dst_path_len = src_path_len;
+ } else {
+ if (strbuf_getline_nul(&rpath, fp))
+ break;
+ dst_path = rpath.buf;
+ dst_path_len = rpath.len;
+ }
+
+ if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
+ strbuf_reset(&buf);
+ strbuf_addf(&buf, "Subproject commit %s",
+ oid_to_hex(&loid));
+ add_left_or_right(&submodules, src_path, buf.buf, 0);
+ strbuf_reset(&buf);
+ strbuf_addf(&buf, "Subproject commit %s",
+ oid_to_hex(&roid));
+ if (!oidcmp(&loid, &roid))
+ strbuf_addstr(&buf, "-dirty");
+ add_left_or_right(&submodules, dst_path, buf.buf, 1);
+ continue;
+ }
+
+ if (S_ISLNK(lmode)) {
+ char *content = read_sha1_file(loid.hash, &type, &size);
+ add_left_or_right(&symlinks2, src_path, content, 0);
+ free(content);
+ }
+
+ if (S_ISLNK(rmode)) {
+ char *content = read_sha1_file(roid.hash, &type, &size);
+ add_left_or_right(&symlinks2, dst_path, content, 1);
+ free(content);
+ }
+
+ if (lmode && status != 'C') {
+ ce->ce_mode = lmode;
+ oidcpy(&ce->oid, &loid);
+ strcpy(ce->name, src_path);
+ ce->ce_namelen = src_path_len;
+ if (checkout_entry(ce, &lstate, NULL))
+ return error("could not write '%s'", src_path);
+ }
+
+ if (rmode) {
+ struct working_tree_entry *entry;
+
+ /* Avoid duplicate working_tree entries */
+ FLEX_ALLOC_STR(entry, path, dst_path);
+ hashmap_entry_init(entry, strhash(dst_path));
+ if (hashmap_get(&working_tree_dups, entry, NULL)) {
+ free(entry);
+ continue;
+ }
+ hashmap_add(&working_tree_dups, entry);
+
+ if (!use_wt_file(workdir, dst_path, &roid)) {
+ ce->ce_mode = rmode;
+ oidcpy(&ce->oid, &roid);
+ strcpy(ce->name, dst_path);
+ ce->ce_namelen = dst_path_len;
+ if (checkout_entry(ce, &rstate, NULL))
+ return error("could not write '%s'",
+ dst_path);
+ } else if (!is_null_oid(&roid)) {
+ /*
+ * Changes in the working tree need special
+ * treatment since they are not part of the
+ * index.
+ */
+ struct cache_entry *ce2 =
+ make_cache_entry(rmode, roid.hash,
+ dst_path, 0, 0);
+
+ add_index_entry(&wtindex, ce2,
+ ADD_CACHE_JUST_APPEND);
+
+ add_path(&rdir, rdir_len, dst_path);
+ if (ensure_leading_directories(rdir.buf))
+ return error("could not create "
+ "directory for '%s'",
+ dst_path);
+ add_path(&wtdir, wtdir_len, dst_path);
+ if (symlinks) {
+ if (symlink(wtdir.buf, rdir.buf)) {
+ ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
+ goto finish;
+ }
+ } else {
+ struct stat st;
+ if (stat(wtdir.buf, &st))
+ st.st_mode = 0644;
+ if (copy_file(rdir.buf, wtdir.buf,
+ st.st_mode)) {
+ ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
+ goto finish;
+ }
+ }
+ }
+ }
+ }
+
+ if (finish_command(&child)) {
+ ret = error("error occurred running diff --raw");
+ goto finish;
+ }
+
+ if (!i)
+ return 0;
+
+ /*
+ * Changes to submodules require special treatment.This loop writes a
+ * temporary file to both the left and right directories to show the
+ * change in the recorded SHA1 for the submodule.
+ */
+ hashmap_iter_init(&submodules, &iter);
+ while ((entry = hashmap_iter_next(&iter))) {
+ if (*entry->left) {
+ add_path(&ldir, ldir_len, entry->path);
+ ensure_leading_directories(ldir.buf);
+ write_file(ldir.buf, "%s", entry->left);
+ }
+ if (*entry->right) {
+ add_path(&rdir, rdir_len, entry->path);
+ ensure_leading_directories(rdir.buf);
+ write_file(rdir.buf, "%s", entry->right);
+ }
+ }
+
+ /*
+ * Symbolic links require special treatment.The standard "git diff"
+ * shows only the link itself, not the contents of the link target.
+ * This loop replicates that behavior.
+ */
+ hashmap_iter_init(&symlinks2, &iter);
+ while ((entry = hashmap_iter_next(&iter))) {
+ if (*entry->left) {
+ add_path(&ldir, ldir_len, entry->path);
+ ensure_leading_directories(ldir.buf);
+ write_file(ldir.buf, "%s", entry->left);
+ }
+ if (*entry->right) {
+ add_path(&rdir, rdir_len, entry->path);
+ ensure_leading_directories(rdir.buf);
+ write_file(rdir.buf, "%s", entry->right);
+ }
+ }
+
+ strbuf_release(&buf);
+
+ strbuf_setlen(&ldir, ldir_len);
+ helper_argv[1] = ldir.buf;
+ strbuf_setlen(&rdir, rdir_len);
+ helper_argv[2] = rdir.buf;
+
+ if (extcmd) {
+ helper_argv[0] = extcmd;
+ flags = 0;
+ } else
+ setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
+ rc = run_command_v_opt(helper_argv, flags);
+
+ /*
+ * If the diff includes working copy files and those
+ * files were modified during the diff, then the changes
+ * should be copied back to the working tree.
+ * Do not copy back files when symlinks are used and the
+ * external tool did not replace the original link with a file.
+ *
+ * These hashes are loaded lazily since they aren't needed
+ * in the common case of --symlinks and the difftool updating
+ * files through the symlink.
+ */
+ hashmap_init(&wt_modified, (hashmap_cmp_fn)path_entry_cmp,
+ wtindex.cache_nr);
+ hashmap_init(&tmp_modified, (hashmap_cmp_fn)path_entry_cmp,
+ wtindex.cache_nr);
+
+ for (i = 0; i < wtindex.cache_nr; i++) {
+ struct hashmap_entry dummy;
+ const char *name = wtindex.cache[i]->name;
+ struct stat st;
+
+ add_path(&rdir, rdir_len, name);
+ if (lstat(rdir.buf, &st))
+ continue;
+
+ if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
+ continue;
+
+ if (!indices_loaded) {
+ static struct lock_file lock;
+ strbuf_reset(&buf);
+ strbuf_addf(&buf, "%s/wtindex", tmpdir);
+ if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
+ write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
+ ret = error("could not write %s", buf.buf);
+ rollback_lock_file(&lock);
+ goto finish;
+ }
+ changed_files(&wt_modified, buf.buf, workdir);
+ strbuf_setlen(&rdir, rdir_len);
+ changed_files(&tmp_modified, buf.buf, rdir.buf);
+ add_path(&rdir, rdir_len, name);
+ indices_loaded = 1;
+ }
+
+ hashmap_entry_init(&dummy, strhash(name));
+ if (hashmap_get(&tmp_modified, &dummy, name)) {
+ add_path(&wtdir, wtdir_len, name);
+ if (hashmap_get(&wt_modified, &dummy, name)) {
+ warning(_("both files modified: '%s' and '%s'."),
+ wtdir.buf, rdir.buf);
+ warning(_("working tree file has been left."));
+ warning("%s", "");
+ err = 1;
+ } else if (unlink(wtdir.buf) ||
+ copy_file(wtdir.buf, rdir.buf, st.st_mode))
+ warning_errno(_("could not copy '%s' to '%s'"),
+ rdir.buf, wtdir.buf);
+ }
+ }
+
+ if (err) {
+ warning(_("temporary files exist in '%s'."), tmpdir);
+ warning(_("you may want to cleanup or recover these."));
+ exit(1);
+ } else
+ exit_cleanup(tmpdir, rc);
+
+finish:
+ free(ce);
+ strbuf_release(&ldir);
+ strbuf_release(&rdir);
+ strbuf_release(&wtdir);
+ strbuf_release(&buf);
+
+ return ret;
+}
+
+static int run_file_diff(int prompt, const char *prefix,
+ int argc, const char **argv)
+{
+ struct argv_array args = ARGV_ARRAY_INIT;
+ const char *env[] = {
+ "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
+ NULL
+ };
+ int ret = 0, i;
+
+ if (prompt > 0)
+ env[2] = "GIT_DIFFTOOL_PROMPT=true";
+ else if (!prompt)
+ env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
+
+
+ argv_array_push(&args, "diff");
+ for (i = 0; i < argc; i++)
+ argv_array_push(&args, argv[i]);
+ ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env);
+ exit(ret);
+}
+
+int cmd_difftool(int argc, const char **argv, const char *prefix)
+{
+ int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
+ tool_help = 0;
+ static char *difftool_cmd = NULL, *extcmd = NULL;
+ struct option builtin_difftool_options[] = {
+ OPT_BOOL('g', "gui", &use_gui_tool,
+ N_("use `diff.guitool` instead of `diff.tool`")),
+ OPT_BOOL('d', "dir-diff", &dir_diff,
+ N_("perform a full-directory diff")),
+ { OPTION_SET_INT, 'y', "no-prompt", &prompt, NULL,
+ N_("do not prompt before launching a diff tool"),
+ PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
+ { OPTION_SET_INT, 0, "prompt", &prompt, NULL, NULL,
+ PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN,
+ NULL, 1 },
+ OPT_BOOL(0, "symlinks", &symlinks,
+ N_("use symlinks in dir-diff mode")),
+ OPT_STRING('t', "tool", &difftool_cmd, N_("<tool>"),
+ N_("use the specified diff tool")),
+ OPT_BOOL(0, "tool-help", &tool_help,
+ N_("print a list of diff tools that may be used with "
+ "`--tool`")),
+ OPT_BOOL(0, "trust-exit-code", &trust_exit_code,
+ N_("make 'git-difftool' exit when an invoked diff "
+ "tool returns a non - zero exit code")),
+ OPT_STRING('x', "extcmd", &extcmd, N_("<command>"),
+ N_("specify a custom command for viewing diffs")),
+ OPT_END()
+ };
+
+ git_config(difftool_config, NULL);
+ symlinks = has_symlinks;
+
+ argc = parse_options(argc, argv, prefix, builtin_difftool_options,
+ builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN |
+ PARSE_OPT_KEEP_DASHDASH);
+
+ if (tool_help)
+ return print_tool_help();
+
+ /* NEEDSWORK: once we no longer spawn anything, remove this */
+ setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
+ setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
+
+ if (use_gui_tool && diff_gui_tool && *diff_gui_tool)
+ setenv("GIT_DIFF_TOOL", diff_gui_tool, 1);
+ else if (difftool_cmd) {
+ if (*difftool_cmd)
+ setenv("GIT_DIFF_TOOL", difftool_cmd, 1);
+ else
+ die(_("no <tool> given for --tool=<tool>"));
+ }
+
+ if (extcmd) {
+ if (*extcmd)
+ setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1);
+ else
+ die(_("no <cmd> given for --extcmd=<cmd>"));
+ }
+
+ setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
+ trust_exit_code ? "true" : "false", 1);
+
+ /*
+ * In directory diff mode, 'git-difftool--helper' is called once
+ * to compare the a / b directories. In file diff mode, 'git diff'
+ * will invoke a separate instance of 'git-difftool--helper' for
+ * each file that changed.
+ */
+ if (dir_diff)
+ return run_dir_diff(extcmd, symlinks, prefix, argc, argv);
+ return run_file_diff(prompt, prefix, argc, argv);
+}