Merge branch 'jt/get-reference-with-commit-graph'
[git] / builtin / help.c
1 /*
2  * Builtin help command
3  */
4 #include "cache.h"
5 #include "config.h"
6 #include "builtin.h"
7 #include "exec-cmd.h"
8 #include "parse-options.h"
9 #include "run-command.h"
10 #include "column.h"
11 #include "help.h"
12 #include "alias.h"
13
14 #ifndef DEFAULT_HELP_FORMAT
15 #define DEFAULT_HELP_FORMAT "man"
16 #endif
17
18 static struct man_viewer_list {
19         struct man_viewer_list *next;
20         char name[FLEX_ARRAY];
21 } *man_viewer_list;
22
23 static struct man_viewer_info_list {
24         struct man_viewer_info_list *next;
25         const char *info;
26         char name[FLEX_ARRAY];
27 } *man_viewer_info_list;
28
29 enum help_format {
30         HELP_FORMAT_NONE,
31         HELP_FORMAT_MAN,
32         HELP_FORMAT_INFO,
33         HELP_FORMAT_WEB
34 };
35
36 static const char *html_path;
37
38 static int show_all = 0;
39 static int show_guides = 0;
40 static int show_config;
41 static int verbose = 1;
42 static unsigned int colopts;
43 static enum help_format help_format = HELP_FORMAT_NONE;
44 static int exclude_guides;
45 static struct option builtin_help_options[] = {
46         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
47         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
48         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
49         OPT_BOOL('c', "config", &show_config, N_("print all configuration variable names")),
50         OPT_SET_INT_F(0, "config-for-completion", &show_config, "", 2, PARSE_OPT_HIDDEN),
51         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
52         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
53                         HELP_FORMAT_WEB),
54         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
55                         HELP_FORMAT_INFO),
56         OPT__VERBOSE(&verbose, N_("print command description")),
57         OPT_END(),
58 };
59
60 static const char * const builtin_help_usage[] = {
61         N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
62         NULL
63 };
64
65 static enum help_format parse_help_format(const char *format)
66 {
67         if (!strcmp(format, "man"))
68                 return HELP_FORMAT_MAN;
69         if (!strcmp(format, "info"))
70                 return HELP_FORMAT_INFO;
71         if (!strcmp(format, "web") || !strcmp(format, "html"))
72                 return HELP_FORMAT_WEB;
73         die(_("unrecognized help format '%s'"), format);
74 }
75
76 static const char *get_man_viewer_info(const char *name)
77 {
78         struct man_viewer_info_list *viewer;
79
80         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
81         {
82                 if (!strcasecmp(name, viewer->name))
83                         return viewer->info;
84         }
85         return NULL;
86 }
87
88 static int check_emacsclient_version(void)
89 {
90         struct strbuf buffer = STRBUF_INIT;
91         struct child_process ec_process = CHILD_PROCESS_INIT;
92         const char *argv_ec[] = { "emacsclient", "--version", NULL };
93         int version;
94
95         /* emacsclient prints its version number on stderr */
96         ec_process.argv = argv_ec;
97         ec_process.err = -1;
98         ec_process.stdout_to_stderr = 1;
99         if (start_command(&ec_process))
100                 return error(_("Failed to start emacsclient."));
101
102         strbuf_read(&buffer, ec_process.err, 20);
103         close(ec_process.err);
104
105         /*
106          * Don't bother checking return value, because "emacsclient --version"
107          * seems to always exits with code 1.
108          */
109         finish_command(&ec_process);
110
111         if (!starts_with(buffer.buf, "emacsclient")) {
112                 strbuf_release(&buffer);
113                 return error(_("Failed to parse emacsclient version."));
114         }
115
116         strbuf_remove(&buffer, 0, strlen("emacsclient"));
117         version = atoi(buffer.buf);
118
119         if (version < 22) {
120                 strbuf_release(&buffer);
121                 return error(_("emacsclient version '%d' too old (< 22)."),
122                         version);
123         }
124
125         strbuf_release(&buffer);
126         return 0;
127 }
128
129 static void exec_woman_emacs(const char *path, const char *page)
130 {
131         if (!check_emacsclient_version()) {
132                 /* This works only with emacsclient version >= 22. */
133                 struct strbuf man_page = STRBUF_INIT;
134
135                 if (!path)
136                         path = "emacsclient";
137                 strbuf_addf(&man_page, "(woman \"%s\")", page);
138                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
139                 warning_errno(_("failed to exec '%s'"), path);
140                 strbuf_release(&man_page);
141         }
142 }
143
144 static void exec_man_konqueror(const char *path, const char *page)
145 {
146         const char *display = getenv("DISPLAY");
147         if (display && *display) {
148                 struct strbuf man_page = STRBUF_INIT;
149                 const char *filename = "kfmclient";
150
151                 /* It's simpler to launch konqueror using kfmclient. */
152                 if (path) {
153                         size_t len;
154                         if (strip_suffix(path, "/konqueror", &len))
155                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
156                         filename = basename((char *)path);
157                 } else
158                         path = "kfmclient";
159                 strbuf_addf(&man_page, "man:%s(1)", page);
160                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
161                 warning_errno(_("failed to exec '%s'"), path);
162                 strbuf_release(&man_page);
163         }
164 }
165
166 static void exec_man_man(const char *path, const char *page)
167 {
168         if (!path)
169                 path = "man";
170         execlp(path, "man", page, (char *)NULL);
171         warning_errno(_("failed to exec '%s'"), path);
172 }
173
174 static void exec_man_cmd(const char *cmd, const char *page)
175 {
176         struct strbuf shell_cmd = STRBUF_INIT;
177         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
178         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
179         warning(_("failed to exec '%s'"), cmd);
180         strbuf_release(&shell_cmd);
181 }
182
183 static void add_man_viewer(const char *name)
184 {
185         struct man_viewer_list **p = &man_viewer_list;
186
187         while (*p)
188                 p = &((*p)->next);
189         FLEX_ALLOC_STR(*p, name, name);
190 }
191
192 static int supported_man_viewer(const char *name, size_t len)
193 {
194         return (!strncasecmp("man", name, len) ||
195                 !strncasecmp("woman", name, len) ||
196                 !strncasecmp("konqueror", name, len));
197 }
198
199 static void do_add_man_viewer_info(const char *name,
200                                    size_t len,
201                                    const char *value)
202 {
203         struct man_viewer_info_list *new_man_viewer;
204         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
205         new_man_viewer->info = xstrdup(value);
206         new_man_viewer->next = man_viewer_info_list;
207         man_viewer_info_list = new_man_viewer;
208 }
209
210 static int add_man_viewer_path(const char *name,
211                                size_t len,
212                                const char *value)
213 {
214         if (supported_man_viewer(name, len))
215                 do_add_man_viewer_info(name, len, value);
216         else
217                 warning(_("'%s': path for unsupported man viewer.\n"
218                           "Please consider using 'man.<tool>.cmd' instead."),
219                         name);
220
221         return 0;
222 }
223
224 static int add_man_viewer_cmd(const char *name,
225                               size_t len,
226                               const char *value)
227 {
228         if (supported_man_viewer(name, len))
229                 warning(_("'%s': cmd for supported man viewer.\n"
230                           "Please consider using 'man.<tool>.path' instead."),
231                         name);
232         else
233                 do_add_man_viewer_info(name, len, value);
234
235         return 0;
236 }
237
238 static int add_man_viewer_info(const char *var, const char *value)
239 {
240         const char *name, *subkey;
241         int namelen;
242
243         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
244                 return 0;
245
246         if (!strcmp(subkey, "path")) {
247                 if (!value)
248                         return config_error_nonbool(var);
249                 return add_man_viewer_path(name, namelen, value);
250         }
251         if (!strcmp(subkey, "cmd")) {
252                 if (!value)
253                         return config_error_nonbool(var);
254                 return add_man_viewer_cmd(name, namelen, value);
255         }
256
257         return 0;
258 }
259
260 static int git_help_config(const char *var, const char *value, void *cb)
261 {
262         if (starts_with(var, "column."))
263                 return git_column_config(var, value, "help", &colopts);
264         if (!strcmp(var, "help.format")) {
265                 if (!value)
266                         return config_error_nonbool(var);
267                 help_format = parse_help_format(value);
268                 return 0;
269         }
270         if (!strcmp(var, "help.htmlpath")) {
271                 if (!value)
272                         return config_error_nonbool(var);
273                 html_path = xstrdup(value);
274                 return 0;
275         }
276         if (!strcmp(var, "man.viewer")) {
277                 if (!value)
278                         return config_error_nonbool(var);
279                 add_man_viewer(value);
280                 return 0;
281         }
282         if (starts_with(var, "man."))
283                 return add_man_viewer_info(var, value);
284
285         return git_default_config(var, value, cb);
286 }
287
288 static struct cmdnames main_cmds, other_cmds;
289
290 static int is_git_command(const char *s)
291 {
292         if (is_builtin(s))
293                 return 1;
294
295         load_command_list("git-", &main_cmds, &other_cmds);
296         return is_in_cmdlist(&main_cmds, s) ||
297                 is_in_cmdlist(&other_cmds, s);
298 }
299
300 static const char *cmd_to_page(const char *git_cmd)
301 {
302         if (!git_cmd)
303                 return "git";
304         else if (starts_with(git_cmd, "git"))
305                 return git_cmd;
306         else if (is_git_command(git_cmd))
307                 return xstrfmt("git-%s", git_cmd);
308         else
309                 return xstrfmt("git%s", git_cmd);
310 }
311
312 static void setup_man_path(void)
313 {
314         struct strbuf new_path = STRBUF_INIT;
315         const char *old_path = getenv("MANPATH");
316         char *git_man_path = system_path(GIT_MAN_PATH);
317
318         /* We should always put ':' after our path. If there is no
319          * old_path, the ':' at the end will let 'man' to try
320          * system-wide paths after ours to find the manual page. If
321          * there is old_path, we need ':' as delimiter. */
322         strbuf_addstr(&new_path, git_man_path);
323         strbuf_addch(&new_path, ':');
324         if (old_path)
325                 strbuf_addstr(&new_path, old_path);
326
327         free(git_man_path);
328         setenv("MANPATH", new_path.buf, 1);
329
330         strbuf_release(&new_path);
331 }
332
333 static void exec_viewer(const char *name, const char *page)
334 {
335         const char *info = get_man_viewer_info(name);
336
337         if (!strcasecmp(name, "man"))
338                 exec_man_man(info, page);
339         else if (!strcasecmp(name, "woman"))
340                 exec_woman_emacs(info, page);
341         else if (!strcasecmp(name, "konqueror"))
342                 exec_man_konqueror(info, page);
343         else if (info)
344                 exec_man_cmd(info, page);
345         else
346                 warning(_("'%s': unknown man viewer."), name);
347 }
348
349 static void show_man_page(const char *git_cmd)
350 {
351         struct man_viewer_list *viewer;
352         const char *page = cmd_to_page(git_cmd);
353         const char *fallback = getenv("GIT_MAN_VIEWER");
354
355         setup_man_path();
356         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
357         {
358                 exec_viewer(viewer->name, page); /* will return when unable */
359         }
360         if (fallback)
361                 exec_viewer(fallback, page);
362         exec_viewer("man", page);
363         die(_("no man viewer handled the request"));
364 }
365
366 static void show_info_page(const char *git_cmd)
367 {
368         const char *page = cmd_to_page(git_cmd);
369         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
370         execlp("info", "info", "gitman", page, (char *)NULL);
371         die(_("no info viewer handled the request"));
372 }
373
374 static void get_html_page_path(struct strbuf *page_path, const char *page)
375 {
376         struct stat st;
377         char *to_free = NULL;
378
379         if (!html_path)
380                 html_path = to_free = system_path(GIT_HTML_PATH);
381
382         /* Check that we have a git documentation directory. */
383         if (!strstr(html_path, "://")) {
384                 if (stat(mkpath("%s/git.html", html_path), &st)
385                     || !S_ISREG(st.st_mode))
386                         die("'%s': not a documentation directory.", html_path);
387         }
388
389         strbuf_init(page_path, 0);
390         strbuf_addf(page_path, "%s/%s.html", html_path, page);
391         free(to_free);
392 }
393
394 static void open_html(const char *path)
395 {
396         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
397 }
398
399 static void show_html_page(const char *git_cmd)
400 {
401         const char *page = cmd_to_page(git_cmd);
402         struct strbuf page_path; /* it leaks but we exec bellow */
403
404         get_html_page_path(&page_path, page);
405
406         open_html(page_path.buf);
407 }
408
409 static const char *check_git_cmd(const char* cmd)
410 {
411         char *alias;
412
413         if (is_git_command(cmd))
414                 return cmd;
415
416         alias = alias_lookup(cmd);
417         if (alias) {
418                 const char **argv;
419                 int count;
420
421                 /*
422                  * handle_builtin() in git.c rewrites "git cmd --help"
423                  * to "git help --exclude-guides cmd", so we can use
424                  * exclude_guides to distinguish "git cmd --help" from
425                  * "git help cmd". In the latter case, or if cmd is an
426                  * alias for a shell command, just print the alias
427                  * definition.
428                  */
429                 if (!exclude_guides || alias[0] == '!') {
430                         printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
431                         free(alias);
432                         exit(0);
433                 }
434                 /*
435                  * Otherwise, we pretend that the command was "git
436                  * word0 --help". We use split_cmdline() to get the
437                  * first word of the alias, to ensure that we use the
438                  * same rules as when the alias is actually
439                  * used. split_cmdline() modifies alias in-place.
440                  */
441                 fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
442                 count = split_cmdline(alias, &argv);
443                 if (count < 0)
444                         die(_("bad alias.%s string: %s"), cmd,
445                             split_cmdline_strerror(count));
446                 free(argv);
447                 UNLEAK(alias);
448                 return alias;
449         }
450
451         if (exclude_guides)
452                 return help_unknown_cmd(cmd);
453
454         return cmd;
455 }
456
457 int cmd_help(int argc, const char **argv, const char *prefix)
458 {
459         int nongit;
460         enum help_format parsed_help_format;
461
462         argc = parse_options(argc, argv, prefix, builtin_help_options,
463                         builtin_help_usage, 0);
464         parsed_help_format = help_format;
465
466         if (show_all) {
467                 git_config(git_help_config, NULL);
468                 if (verbose) {
469                         setup_pager();
470                         list_all_cmds_help();
471                         return 0;
472                 }
473                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
474                 load_command_list("git-", &main_cmds, &other_cmds);
475                 list_commands(colopts, &main_cmds, &other_cmds);
476         }
477
478         if (show_config) {
479                 int for_human = show_config == 1;
480
481                 if (!for_human) {
482                         list_config_help(for_human);
483                         return 0;
484                 }
485                 setup_pager();
486                 list_config_help(for_human);
487                 printf("\n%s\n", _("'git help config' for more information"));
488                 return 0;
489         }
490
491         if (show_guides)
492                 list_common_guides_help();
493
494         if (show_all || show_guides) {
495                 printf("%s\n", _(git_more_info_string));
496                 /*
497                 * We're done. Ignore any remaining args
498                 */
499                 return 0;
500         }
501
502         if (!argv[0]) {
503                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
504                 list_common_cmds_help();
505                 printf("\n%s\n", _(git_more_info_string));
506                 return 0;
507         }
508
509         setup_git_directory_gently(&nongit);
510         git_config(git_help_config, NULL);
511
512         if (parsed_help_format != HELP_FORMAT_NONE)
513                 help_format = parsed_help_format;
514         if (help_format == HELP_FORMAT_NONE)
515                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
516
517         argv[0] = check_git_cmd(argv[0]);
518
519         switch (help_format) {
520         case HELP_FORMAT_NONE:
521         case HELP_FORMAT_MAN:
522                 show_man_page(argv[0]);
523                 break;
524         case HELP_FORMAT_INFO:
525                 show_info_page(argv[0]);
526                 break;
527         case HELP_FORMAT_WEB:
528                 show_html_page(argv[0]);
529                 break;
530         }
531
532         return 0;
533 }