checkout: split part of it to new command 'switch'
[git] / git.c
1 #include "builtin.h"
2 #include "config.h"
3 #include "exec-cmd.h"
4 #include "help.h"
5 #include "run-command.h"
6 #include "alias.h"
7
8 #define RUN_SETUP               (1<<0)
9 #define RUN_SETUP_GENTLY        (1<<1)
10 #define USE_PAGER               (1<<2)
11 /*
12  * require working tree to be present -- anything uses this needs
13  * RUN_SETUP for reading from the configuration file.
14  */
15 #define NEED_WORK_TREE          (1<<3)
16 #define SUPPORT_SUPER_PREFIX    (1<<4)
17 #define DELAY_PAGER_CONFIG      (1<<5)
18 #define NO_PARSEOPT             (1<<6) /* parse-options is not used */
19
20 struct cmd_struct {
21         const char *cmd;
22         int (*fn)(int, const char **, const char *);
23         unsigned int option;
24 };
25
26 const char git_usage_string[] =
27         N_("git [--version] [--help] [-C <path>] [-c <name>=<value>]\n"
28            "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
29            "           [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]\n"
30            "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
31            "           <command> [<args>]");
32
33 const char git_more_info_string[] =
34         N_("'git help -a' and 'git help -g' list available subcommands and some\n"
35            "concept guides. See 'git help <command>' or 'git help <concept>'\n"
36            "to read about a specific subcommand or concept.");
37
38 static int use_pager = -1;
39
40 static void list_builtins(struct string_list *list, unsigned int exclude_option);
41
42 static void exclude_helpers_from_list(struct string_list *list)
43 {
44         int i = 0;
45
46         while (i < list->nr) {
47                 if (strstr(list->items[i].string, "--"))
48                         unsorted_string_list_delete_item(list, i, 0);
49                 else
50                         i++;
51         }
52 }
53
54 static int match_token(const char *spec, int len, const char *token)
55 {
56         int token_len = strlen(token);
57
58         return len == token_len && !strncmp(spec, token, token_len);
59 }
60
61 static int list_cmds(const char *spec)
62 {
63         struct string_list list = STRING_LIST_INIT_DUP;
64         int i;
65
66         while (*spec) {
67                 const char *sep = strchrnul(spec, ',');
68                 int len = sep - spec;
69
70                 if (match_token(spec, len, "builtins"))
71                         list_builtins(&list, 0);
72                 else if (match_token(spec, len, "main"))
73                         list_all_main_cmds(&list);
74                 else if (match_token(spec, len, "others"))
75                         list_all_other_cmds(&list);
76                 else if (match_token(spec, len, "nohelpers"))
77                         exclude_helpers_from_list(&list);
78                 else if (match_token(spec, len, "alias"))
79                         list_aliases(&list);
80                 else if (match_token(spec, len, "config"))
81                         list_cmds_by_config(&list);
82                 else if (len > 5 && !strncmp(spec, "list-", 5)) {
83                         struct strbuf sb = STRBUF_INIT;
84
85                         strbuf_add(&sb, spec + 5, len - 5);
86                         list_cmds_by_category(&list, sb.buf);
87                         strbuf_release(&sb);
88                 }
89                 else
90                         die(_("unsupported command listing type '%s'"), spec);
91                 spec += len;
92                 if (*spec == ',')
93                         spec++;
94         }
95         for (i = 0; i < list.nr; i++)
96                 puts(list.items[i].string);
97         string_list_clear(&list, 0);
98         return 0;
99 }
100
101 static void commit_pager_choice(void)
102 {
103         switch (use_pager) {
104         case 0:
105                 setenv("GIT_PAGER", "cat", 1);
106                 break;
107         case 1:
108                 setup_pager();
109                 break;
110         default:
111                 break;
112         }
113 }
114
115 void setup_auto_pager(const char *cmd, int def)
116 {
117         if (use_pager != -1 || pager_in_use())
118                 return;
119         use_pager = check_pager_config(cmd);
120         if (use_pager == -1)
121                 use_pager = def;
122         commit_pager_choice();
123 }
124
125 static int handle_options(const char ***argv, int *argc, int *envchanged)
126 {
127         const char **orig_argv = *argv;
128
129         while (*argc > 0) {
130                 const char *cmd = (*argv)[0];
131                 if (cmd[0] != '-')
132                         break;
133
134                 /*
135                  * For legacy reasons, the "version" and "help"
136                  * commands can be written with "--" prepended
137                  * to make them look like flags.
138                  */
139                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
140                         break;
141
142                 /*
143                  * Check remaining flags.
144                  */
145                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
146                         if (*cmd == '=')
147                                 git_set_exec_path(cmd + 1);
148                         else {
149                                 puts(git_exec_path());
150                                 trace2_cmd_name("_query_");
151                                 exit(0);
152                         }
153                 } else if (!strcmp(cmd, "--html-path")) {
154                         puts(system_path(GIT_HTML_PATH));
155                         trace2_cmd_name("_query_");
156                         exit(0);
157                 } else if (!strcmp(cmd, "--man-path")) {
158                         puts(system_path(GIT_MAN_PATH));
159                         trace2_cmd_name("_query_");
160                         exit(0);
161                 } else if (!strcmp(cmd, "--info-path")) {
162                         puts(system_path(GIT_INFO_PATH));
163                         trace2_cmd_name("_query_");
164                         exit(0);
165                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
166                         use_pager = 1;
167                 } else if (!strcmp(cmd, "-P") || !strcmp(cmd, "--no-pager")) {
168                         use_pager = 0;
169                         if (envchanged)
170                                 *envchanged = 1;
171                 } else if (!strcmp(cmd, "--no-replace-objects")) {
172                         read_replace_refs = 0;
173                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
174                         if (envchanged)
175                                 *envchanged = 1;
176                 } else if (!strcmp(cmd, "--git-dir")) {
177                         if (*argc < 2) {
178                                 fprintf(stderr, _("no directory given for --git-dir\n" ));
179                                 usage(git_usage_string);
180                         }
181                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
182                         if (envchanged)
183                                 *envchanged = 1;
184                         (*argv)++;
185                         (*argc)--;
186                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
187                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
188                         if (envchanged)
189                                 *envchanged = 1;
190                 } else if (!strcmp(cmd, "--namespace")) {
191                         if (*argc < 2) {
192                                 fprintf(stderr, _("no namespace given for --namespace\n" ));
193                                 usage(git_usage_string);
194                         }
195                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
196                         if (envchanged)
197                                 *envchanged = 1;
198                         (*argv)++;
199                         (*argc)--;
200                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
201                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
202                         if (envchanged)
203                                 *envchanged = 1;
204                 } else if (!strcmp(cmd, "--work-tree")) {
205                         if (*argc < 2) {
206                                 fprintf(stderr, _("no directory given for --work-tree\n" ));
207                                 usage(git_usage_string);
208                         }
209                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
210                         if (envchanged)
211                                 *envchanged = 1;
212                         (*argv)++;
213                         (*argc)--;
214                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
215                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
216                         if (envchanged)
217                                 *envchanged = 1;
218                 } else if (!strcmp(cmd, "--super-prefix")) {
219                         if (*argc < 2) {
220                                 fprintf(stderr, _("no prefix given for --super-prefix\n" ));
221                                 usage(git_usage_string);
222                         }
223                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
224                         if (envchanged)
225                                 *envchanged = 1;
226                         (*argv)++;
227                         (*argc)--;
228                 } else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
229                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
230                         if (envchanged)
231                                 *envchanged = 1;
232                 } else if (!strcmp(cmd, "--bare")) {
233                         char *cwd = xgetcwd();
234                         is_bare_repository_cfg = 1;
235                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
236                         free(cwd);
237                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
238                         if (envchanged)
239                                 *envchanged = 1;
240                 } else if (!strcmp(cmd, "-c")) {
241                         if (*argc < 2) {
242                                 fprintf(stderr, _("-c expects a configuration string\n" ));
243                                 usage(git_usage_string);
244                         }
245                         git_config_push_parameter((*argv)[1]);
246                         (*argv)++;
247                         (*argc)--;
248                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
249                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
250                         if (envchanged)
251                                 *envchanged = 1;
252                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
253                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
254                         if (envchanged)
255                                 *envchanged = 1;
256                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
257                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
258                         if (envchanged)
259                                 *envchanged = 1;
260                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
261                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
262                         if (envchanged)
263                                 *envchanged = 1;
264                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
265                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
266                         if (envchanged)
267                                 *envchanged = 1;
268                 } else if (!strcmp(cmd, "--no-optional-locks")) {
269                         setenv(GIT_OPTIONAL_LOCKS_ENVIRONMENT, "0", 1);
270                         if (envchanged)
271                                 *envchanged = 1;
272                 } else if (!strcmp(cmd, "--shallow-file")) {
273                         (*argv)++;
274                         (*argc)--;
275                         set_alternate_shallow_file(the_repository, (*argv)[0], 1);
276                         if (envchanged)
277                                 *envchanged = 1;
278                 } else if (!strcmp(cmd, "-C")) {
279                         if (*argc < 2) {
280                                 fprintf(stderr, _("no directory given for -C\n" ));
281                                 usage(git_usage_string);
282                         }
283                         if ((*argv)[1][0]) {
284                                 if (chdir((*argv)[1]))
285                                         die_errno("cannot change to '%s'", (*argv)[1]);
286                                 if (envchanged)
287                                         *envchanged = 1;
288                         }
289                         (*argv)++;
290                         (*argc)--;
291                 } else if (skip_prefix(cmd, "--list-cmds=", &cmd)) {
292                         trace2_cmd_name("_query_");
293                         if (!strcmp(cmd, "parseopt")) {
294                                 struct string_list list = STRING_LIST_INIT_DUP;
295                                 int i;
296
297                                 list_builtins(&list, NO_PARSEOPT);
298                                 for (i = 0; i < list.nr; i++)
299                                         printf("%s ", list.items[i].string);
300                                 string_list_clear(&list, 0);
301                                 exit(0);
302                         } else {
303                                 exit(list_cmds(cmd));
304                         }
305                 } else {
306                         fprintf(stderr, _("unknown option: %s\n"), cmd);
307                         usage(git_usage_string);
308                 }
309
310                 (*argv)++;
311                 (*argc)--;
312         }
313         return (*argv) - orig_argv;
314 }
315
316 static int handle_alias(int *argcp, const char ***argv)
317 {
318         int envchanged = 0, ret = 0, saved_errno = errno;
319         int count, option_count;
320         const char **new_argv;
321         const char *alias_command;
322         char *alias_string;
323
324         alias_command = (*argv)[0];
325         alias_string = alias_lookup(alias_command);
326         if (alias_string) {
327                 if (*argcp > 1 && !strcmp((*argv)[1], "-h"))
328                         fprintf_ln(stderr, _("'%s' is aliased to '%s'"),
329                                    alias_command, alias_string);
330                 if (alias_string[0] == '!') {
331                         struct child_process child = CHILD_PROCESS_INIT;
332                         int nongit_ok;
333
334                         /* Aliases expect GIT_PREFIX, GIT_DIR etc to be set */
335                         setup_git_directory_gently(&nongit_ok);
336
337                         commit_pager_choice();
338
339                         child.use_shell = 1;
340                         child.trace2_child_class = "shell_alias";
341                         argv_array_push(&child.args, alias_string + 1);
342                         argv_array_pushv(&child.args, (*argv) + 1);
343
344                         trace2_cmd_alias(alias_command, child.args.argv);
345                         trace2_cmd_list_config();
346                         trace2_cmd_name("_run_shell_alias_");
347
348                         ret = run_command(&child);
349                         if (ret >= 0)   /* normal exit */
350                                 exit(ret);
351
352                         die_errno(_("while expanding alias '%s': '%s'"),
353                                   alias_command, alias_string + 1);
354                 }
355                 count = split_cmdline(alias_string, &new_argv);
356                 if (count < 0)
357                         die(_("bad alias.%s string: %s"), alias_command,
358                             _(split_cmdline_strerror(count)));
359                 option_count = handle_options(&new_argv, &count, &envchanged);
360                 if (envchanged)
361                         die(_("alias '%s' changes environment variables.\n"
362                               "You can use '!git' in the alias to do this"),
363                             alias_command);
364                 memmove(new_argv - option_count, new_argv,
365                                 count * sizeof(char *));
366                 new_argv -= option_count;
367
368                 if (count < 1)
369                         die(_("empty alias for %s"), alias_command);
370
371                 if (!strcmp(alias_command, new_argv[0]))
372                         die(_("recursive alias: %s"), alias_command);
373
374                 trace_argv_printf(new_argv,
375                                   "trace: alias expansion: %s =>",
376                                   alias_command);
377
378                 REALLOC_ARRAY(new_argv, count + *argcp);
379                 /* insert after command name */
380                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
381
382                 trace2_cmd_alias(alias_command, new_argv);
383                 trace2_cmd_list_config();
384
385                 *argv = new_argv;
386                 *argcp += count - 1;
387
388                 ret = 1;
389         }
390
391         errno = saved_errno;
392
393         return ret;
394 }
395
396 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
397 {
398         int status, help;
399         struct stat st;
400         const char *prefix;
401
402         prefix = NULL;
403         help = argc == 2 && !strcmp(argv[1], "-h");
404         if (!help) {
405                 if (p->option & RUN_SETUP)
406                         prefix = setup_git_directory();
407                 else if (p->option & RUN_SETUP_GENTLY) {
408                         int nongit_ok;
409                         prefix = setup_git_directory_gently(&nongit_ok);
410                 }
411
412                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY) &&
413                     !(p->option & DELAY_PAGER_CONFIG))
414                         use_pager = check_pager_config(p->cmd);
415                 if (use_pager == -1 && p->option & USE_PAGER)
416                         use_pager = 1;
417
418                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
419                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
420                         trace_repo_setup(prefix);
421         }
422         commit_pager_choice();
423
424         if (!help && get_super_prefix()) {
425                 if (!(p->option & SUPPORT_SUPER_PREFIX))
426                         die(_("%s doesn't support --super-prefix"), p->cmd);
427         }
428
429         if (!help && p->option & NEED_WORK_TREE)
430                 setup_work_tree();
431
432         trace_argv_printf(argv, "trace: built-in: git");
433         trace2_cmd_name(p->cmd);
434         trace2_cmd_list_config();
435
436         validate_cache_entries(the_repository->index);
437         status = p->fn(argc, argv, prefix);
438         validate_cache_entries(the_repository->index);
439
440         if (status)
441                 return status;
442
443         /* Somebody closed stdout? */
444         if (fstat(fileno(stdout), &st))
445                 return 0;
446         /* Ignore write errors for pipes and sockets.. */
447         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
448                 return 0;
449
450         /* Check for ENOSPC and EIO errors.. */
451         if (fflush(stdout))
452                 die_errno(_("write failure on standard output"));
453         if (ferror(stdout))
454                 die(_("unknown write failure on standard output"));
455         if (fclose(stdout))
456                 die_errno(_("close failed on standard output"));
457         return 0;
458 }
459
460 static struct cmd_struct commands[] = {
461         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
462         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
463         { "annotate", cmd_annotate, RUN_SETUP | NO_PARSEOPT },
464         { "apply", cmd_apply, RUN_SETUP_GENTLY },
465         { "archive", cmd_archive, RUN_SETUP_GENTLY },
466         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
467         { "blame", cmd_blame, RUN_SETUP },
468         { "branch", cmd_branch, RUN_SETUP | DELAY_PAGER_CONFIG },
469         { "bundle", cmd_bundle, RUN_SETUP_GENTLY | NO_PARSEOPT },
470         { "cat-file", cmd_cat_file, RUN_SETUP },
471         { "check-attr", cmd_check_attr, RUN_SETUP },
472         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
473         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
474         { "check-ref-format", cmd_check_ref_format, NO_PARSEOPT  },
475         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
476         { "checkout-index", cmd_checkout_index,
477                 RUN_SETUP | NEED_WORK_TREE},
478         { "cherry", cmd_cherry, RUN_SETUP },
479         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
480         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
481         { "clone", cmd_clone },
482         { "column", cmd_column, RUN_SETUP_GENTLY },
483         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
484         { "commit-graph", cmd_commit_graph, RUN_SETUP },
485         { "commit-tree", cmd_commit_tree, RUN_SETUP | NO_PARSEOPT },
486         { "config", cmd_config, RUN_SETUP_GENTLY | DELAY_PAGER_CONFIG },
487         { "count-objects", cmd_count_objects, RUN_SETUP },
488         { "credential", cmd_credential, RUN_SETUP_GENTLY | NO_PARSEOPT },
489         { "describe", cmd_describe, RUN_SETUP },
490         { "diff", cmd_diff, NO_PARSEOPT },
491         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
492         { "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT },
493         { "diff-tree", cmd_diff_tree, RUN_SETUP | NO_PARSEOPT },
494         { "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
495         { "fast-export", cmd_fast_export, RUN_SETUP },
496         { "fetch", cmd_fetch, RUN_SETUP },
497         { "fetch-pack", cmd_fetch_pack, RUN_SETUP | NO_PARSEOPT },
498         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
499         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
500         { "format-patch", cmd_format_patch, RUN_SETUP },
501         { "fsck", cmd_fsck, RUN_SETUP },
502         { "fsck-objects", cmd_fsck, RUN_SETUP },
503         { "gc", cmd_gc, RUN_SETUP },
504         { "get-tar-commit-id", cmd_get_tar_commit_id, NO_PARSEOPT },
505         { "grep", cmd_grep, RUN_SETUP_GENTLY },
506         { "hash-object", cmd_hash_object },
507         { "help", cmd_help },
508         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY | NO_PARSEOPT },
509         { "init", cmd_init_db },
510         { "init-db", cmd_init_db },
511         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
512         { "log", cmd_log, RUN_SETUP },
513         { "ls-files", cmd_ls_files, RUN_SETUP },
514         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
515         { "ls-tree", cmd_ls_tree, RUN_SETUP },
516         { "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY | NO_PARSEOPT },
517         { "mailsplit", cmd_mailsplit, NO_PARSEOPT },
518         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
519         { "merge-base", cmd_merge_base, RUN_SETUP },
520         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
521         { "merge-index", cmd_merge_index, RUN_SETUP | NO_PARSEOPT },
522         { "merge-ours", cmd_merge_ours, RUN_SETUP | NO_PARSEOPT },
523         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
524         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
525         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
526         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
527         { "merge-tree", cmd_merge_tree, RUN_SETUP | NO_PARSEOPT },
528         { "mktag", cmd_mktag, RUN_SETUP | NO_PARSEOPT },
529         { "mktree", cmd_mktree, RUN_SETUP },
530         { "multi-pack-index", cmd_multi_pack_index, RUN_SETUP_GENTLY },
531         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
532         { "name-rev", cmd_name_rev, RUN_SETUP },
533         { "notes", cmd_notes, RUN_SETUP },
534         { "pack-objects", cmd_pack_objects, RUN_SETUP },
535         { "pack-redundant", cmd_pack_redundant, RUN_SETUP | NO_PARSEOPT },
536         { "pack-refs", cmd_pack_refs, RUN_SETUP },
537         { "patch-id", cmd_patch_id, RUN_SETUP_GENTLY | NO_PARSEOPT },
538         { "pickaxe", cmd_blame, RUN_SETUP },
539         { "prune", cmd_prune, RUN_SETUP },
540         { "prune-packed", cmd_prune_packed, RUN_SETUP },
541         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
542         { "push", cmd_push, RUN_SETUP },
543         { "range-diff", cmd_range_diff, RUN_SETUP | USE_PAGER },
544         { "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
545         /*
546          * NEEDSWORK: Until the rebase is independent and needs no redirection
547          * to rebase shell script this is kept as is, then should be changed to
548          * RUN_SETUP | NEED_WORK_TREE
549          */
550         { "rebase", cmd_rebase },
551         { "rebase--interactive", cmd_rebase__interactive, RUN_SETUP | NEED_WORK_TREE },
552         { "receive-pack", cmd_receive_pack },
553         { "reflog", cmd_reflog, RUN_SETUP },
554         { "remote", cmd_remote, RUN_SETUP },
555         { "remote-ext", cmd_remote_ext, NO_PARSEOPT },
556         { "remote-fd", cmd_remote_fd, NO_PARSEOPT },
557         { "repack", cmd_repack, RUN_SETUP },
558         { "replace", cmd_replace, RUN_SETUP },
559         { "rerere", cmd_rerere, RUN_SETUP },
560         { "reset", cmd_reset, RUN_SETUP },
561         { "rev-list", cmd_rev_list, RUN_SETUP | NO_PARSEOPT },
562         { "rev-parse", cmd_rev_parse, NO_PARSEOPT },
563         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
564         { "rm", cmd_rm, RUN_SETUP },
565         { "send-pack", cmd_send_pack, RUN_SETUP },
566         { "serve", cmd_serve, RUN_SETUP },
567         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
568         { "show", cmd_show, RUN_SETUP },
569         { "show-branch", cmd_show_branch, RUN_SETUP },
570         { "show-index", cmd_show_index },
571         { "show-ref", cmd_show_ref, RUN_SETUP },
572         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
573         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
574         { "stripspace", cmd_stripspace },
575         { "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },
576         { "switch", cmd_switch, RUN_SETUP | NEED_WORK_TREE },
577         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
578         { "tag", cmd_tag, RUN_SETUP | DELAY_PAGER_CONFIG },
579         { "unpack-file", cmd_unpack_file, RUN_SETUP | NO_PARSEOPT },
580         { "unpack-objects", cmd_unpack_objects, RUN_SETUP | NO_PARSEOPT },
581         { "update-index", cmd_update_index, RUN_SETUP },
582         { "update-ref", cmd_update_ref, RUN_SETUP },
583         { "update-server-info", cmd_update_server_info, RUN_SETUP },
584         { "upload-archive", cmd_upload_archive, NO_PARSEOPT },
585         { "upload-archive--writer", cmd_upload_archive_writer, NO_PARSEOPT },
586         { "upload-pack", cmd_upload_pack },
587         { "var", cmd_var, RUN_SETUP_GENTLY | NO_PARSEOPT },
588         { "verify-commit", cmd_verify_commit, RUN_SETUP },
589         { "verify-pack", cmd_verify_pack },
590         { "verify-tag", cmd_verify_tag, RUN_SETUP },
591         { "version", cmd_version },
592         { "whatchanged", cmd_whatchanged, RUN_SETUP },
593         { "worktree", cmd_worktree, RUN_SETUP | NO_PARSEOPT },
594         { "write-tree", cmd_write_tree, RUN_SETUP },
595 };
596
597 static struct cmd_struct *get_builtin(const char *s)
598 {
599         int i;
600         for (i = 0; i < ARRAY_SIZE(commands); i++) {
601                 struct cmd_struct *p = commands + i;
602                 if (!strcmp(s, p->cmd))
603                         return p;
604         }
605         return NULL;
606 }
607
608 int is_builtin(const char *s)
609 {
610         return !!get_builtin(s);
611 }
612
613 static void list_builtins(struct string_list *out, unsigned int exclude_option)
614 {
615         int i;
616         for (i = 0; i < ARRAY_SIZE(commands); i++) {
617                 if (exclude_option &&
618                     (commands[i].option & exclude_option))
619                         continue;
620                 string_list_append(out, commands[i].cmd);
621         }
622 }
623
624 #ifdef STRIP_EXTENSION
625 static void strip_extension(const char **argv)
626 {
627         size_t len;
628
629         if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
630                 argv[0] = xmemdupz(argv[0], len);
631 }
632 #else
633 #define strip_extension(cmd)
634 #endif
635
636 static void handle_builtin(int argc, const char **argv)
637 {
638         struct argv_array args = ARGV_ARRAY_INIT;
639         const char *cmd;
640         struct cmd_struct *builtin;
641
642         strip_extension(argv);
643         cmd = argv[0];
644
645         /* Turn "git cmd --help" into "git help --exclude-guides cmd" */
646         if (argc > 1 && !strcmp(argv[1], "--help")) {
647                 int i;
648
649                 argv[1] = argv[0];
650                 argv[0] = cmd = "help";
651
652                 for (i = 0; i < argc; i++) {
653                         argv_array_push(&args, argv[i]);
654                         if (!i)
655                                 argv_array_push(&args, "--exclude-guides");
656                 }
657
658                 argc++;
659                 argv = args.argv;
660         }
661
662         builtin = get_builtin(cmd);
663         if (builtin)
664                 exit(run_builtin(builtin, argc, argv));
665         argv_array_clear(&args);
666 }
667
668 static void execv_dashed_external(const char **argv)
669 {
670         struct child_process cmd = CHILD_PROCESS_INIT;
671         int status;
672
673         if (get_super_prefix())
674                 die(_("%s doesn't support --super-prefix"), argv[0]);
675
676         if (use_pager == -1 && !is_builtin(argv[0]))
677                 use_pager = check_pager_config(argv[0]);
678         commit_pager_choice();
679
680         argv_array_pushf(&cmd.args, "git-%s", argv[0]);
681         argv_array_pushv(&cmd.args, argv + 1);
682         cmd.clean_on_exit = 1;
683         cmd.wait_after_clean = 1;
684         cmd.silent_exec_failure = 1;
685         cmd.trace2_child_class = "dashed";
686
687         trace2_cmd_name("_run_dashed_");
688
689         /*
690          * The code in run_command() logs trace2 child_start/child_exit
691          * events, so we do not need to report exec/exec_result events here.
692          */
693         trace_argv_printf(cmd.args.argv, "trace: exec:");
694
695         /*
696          * If we fail because the command is not found, it is
697          * OK to return. Otherwise, we just pass along the status code,
698          * or our usual generic code if we were not even able to exec
699          * the program.
700          */
701         status = run_command(&cmd);
702
703         /*
704          * If the child process ran and we are now going to exit, emit a
705          * generic string as our trace2 command verb to indicate that we
706          * launched a dashed command.
707          */
708         if (status >= 0)
709                 exit(status);
710         else if (errno != ENOENT)
711                 exit(128);
712 }
713
714 static int run_argv(int *argcp, const char ***argv)
715 {
716         int done_alias = 0;
717         struct string_list cmd_list = STRING_LIST_INIT_NODUP;
718         struct string_list_item *seen;
719
720         while (1) {
721                 /*
722                  * If we tried alias and futzed with our environment,
723                  * it no longer is safe to invoke builtins directly in
724                  * general.  We have to spawn them as dashed externals.
725                  *
726                  * NEEDSWORK: if we can figure out cases
727                  * where it is safe to do, we can avoid spawning a new
728                  * process.
729                  */
730                 if (!done_alias)
731                         handle_builtin(*argcp, *argv);
732
733 #if 0 // TODO In GFW, need to amend a7924b655e940b06cb547c235d6bed9767929673 to include trace2_ and _tr2 lines.
734                 else if (get_builtin(**argv)) {
735                         struct argv_array args = ARGV_ARRAY_INIT;
736                         int i;
737
738                         /*
739                          * The current process is committed to launching a
740                          * child process to run the command named in (**argv)
741                          * and exiting.  Log a generic string as the trace2
742                          * command verb to indicate this.  Note that the child
743                          * process will log the actual verb when it runs.
744                          */
745                         trace2_cmd_name("_run_git_alias_");
746
747                         if (get_super_prefix())
748                                 die("%s doesn't support --super-prefix", **argv);
749
750                         commit_pager_choice();
751
752                         argv_array_push(&args, "git");
753                         for (i = 0; i < *argcp; i++)
754                                 argv_array_push(&args, (*argv)[i]);
755
756                         trace_argv_printf(args.argv, "trace: exec:");
757
758                         /*
759                          * if we fail because the command is not found, it is
760                          * OK to return. Otherwise, we just pass along the status code.
761                          */
762                         i = run_command_v_opt_tr2(args.argv, RUN_SILENT_EXEC_FAILURE |
763                                                   RUN_CLEAN_ON_EXIT, "git_alias");
764                         if (i >= 0 || errno != ENOENT)
765                                 exit(i);
766                         die("could not execute builtin %s", **argv);
767                 }
768 #endif // a7924b655e940b06cb547c235d6bed9767929673
769
770                 /* .. then try the external ones */
771                 execv_dashed_external(*argv);
772
773                 seen = unsorted_string_list_lookup(&cmd_list, *argv[0]);
774                 if (seen) {
775                         int i;
776                         struct strbuf sb = STRBUF_INIT;
777                         for (i = 0; i < cmd_list.nr; i++) {
778                                 struct string_list_item *item = &cmd_list.items[i];
779
780                                 strbuf_addf(&sb, "\n  %s", item->string);
781                                 if (item == seen)
782                                         strbuf_addstr(&sb, " <==");
783                                 else if (i == cmd_list.nr - 1)
784                                         strbuf_addstr(&sb, " ==>");
785                         }
786                         die(_("alias loop detected: expansion of '%s' does"
787                               " not terminate:%s"), cmd_list.items[0].string, sb.buf);
788                 }
789
790                 string_list_append(&cmd_list, *argv[0]);
791
792                 /*
793                  * It could be an alias -- this works around the insanity
794                  * of overriding "git log" with "git show" by having
795                  * alias.log = show
796                  */
797                 if (!handle_alias(argcp, argv))
798                         break;
799                 done_alias = 1;
800         }
801
802         string_list_clear(&cmd_list, 0);
803
804         return done_alias;
805 }
806
807 int cmd_main(int argc, const char **argv)
808 {
809         const char *cmd;
810         int done_help = 0;
811
812         cmd = argv[0];
813         if (!cmd)
814                 cmd = "git-help";
815         else {
816                 const char *slash = find_last_dir_sep(cmd);
817                 if (slash)
818                         cmd = slash + 1;
819         }
820
821         trace_command_performance(argv);
822
823         /*
824          * "git-xxxx" is the same as "git xxxx", but we obviously:
825          *
826          *  - cannot take flags in between the "git" and the "xxxx".
827          *  - cannot execute it externally (since it would just do
828          *    the same thing over again)
829          *
830          * So we just directly call the builtin handler, and die if
831          * that one cannot handle it.
832          */
833         if (skip_prefix(cmd, "git-", &cmd)) {
834                 argv[0] = cmd;
835                 handle_builtin(argc, argv);
836                 die(_("cannot handle %s as a builtin"), cmd);
837         }
838
839         /* Look for flags.. */
840         argv++;
841         argc--;
842         handle_options(&argv, &argc, NULL);
843         if (argc > 0) {
844                 /* translate --help and --version into commands */
845                 skip_prefix(argv[0], "--", &argv[0]);
846         } else {
847                 /* The user didn't specify a command; give them help */
848                 commit_pager_choice();
849                 printf(_("usage: %s\n\n"), git_usage_string);
850                 list_common_cmds_help();
851                 printf("\n%s\n", _(git_more_info_string));
852                 exit(1);
853         }
854         cmd = argv[0];
855
856         /*
857          * We use PATH to find git commands, but we prepend some higher
858          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
859          * environment, and the $(gitexecdir) from the Makefile at build
860          * time.
861          */
862         setup_path();
863
864         while (1) {
865                 int was_alias = run_argv(&argc, &argv);
866                 if (errno != ENOENT)
867                         break;
868                 if (was_alias) {
869                         fprintf(stderr, _("expansion of alias '%s' failed; "
870                                           "'%s' is not a git command\n"),
871                                 cmd, argv[0]);
872                         exit(1);
873                 }
874                 if (!done_help) {
875                         cmd = argv[0] = help_unknown_cmd(cmd);
876                         done_help = 1;
877                 } else
878                         break;
879         }
880
881         fprintf(stderr, _("failed to run command '%s': %s\n"),
882                 cmd, strerror(errno));
883
884         return 1;
885 }