Merge branch 'po/describe-not-necessarily-7'
[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         /*
74          * Please update _git_config() in git-completion.bash when you
75          * add new help formats.
76          */
77         die(_("unrecognized help format '%s'"), format);
78 }
79
80 static const char *get_man_viewer_info(const char *name)
81 {
82         struct man_viewer_info_list *viewer;
83
84         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
85         {
86                 if (!strcasecmp(name, viewer->name))
87                         return viewer->info;
88         }
89         return NULL;
90 }
91
92 static int check_emacsclient_version(void)
93 {
94         struct strbuf buffer = STRBUF_INIT;
95         struct child_process ec_process = CHILD_PROCESS_INIT;
96         const char *argv_ec[] = { "emacsclient", "--version", NULL };
97         int version;
98
99         /* emacsclient prints its version number on stderr */
100         ec_process.argv = argv_ec;
101         ec_process.err = -1;
102         ec_process.stdout_to_stderr = 1;
103         if (start_command(&ec_process))
104                 return error(_("Failed to start emacsclient."));
105
106         strbuf_read(&buffer, ec_process.err, 20);
107         close(ec_process.err);
108
109         /*
110          * Don't bother checking return value, because "emacsclient --version"
111          * seems to always exits with code 1.
112          */
113         finish_command(&ec_process);
114
115         if (!starts_with(buffer.buf, "emacsclient")) {
116                 strbuf_release(&buffer);
117                 return error(_("Failed to parse emacsclient version."));
118         }
119
120         strbuf_remove(&buffer, 0, strlen("emacsclient"));
121         version = atoi(buffer.buf);
122
123         if (version < 22) {
124                 strbuf_release(&buffer);
125                 return error(_("emacsclient version '%d' too old (< 22)."),
126                         version);
127         }
128
129         strbuf_release(&buffer);
130         return 0;
131 }
132
133 static void exec_woman_emacs(const char *path, const char *page)
134 {
135         if (!check_emacsclient_version()) {
136                 /* This works only with emacsclient version >= 22. */
137                 struct strbuf man_page = STRBUF_INIT;
138
139                 if (!path)
140                         path = "emacsclient";
141                 strbuf_addf(&man_page, "(woman \"%s\")", page);
142                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
143                 warning_errno(_("failed to exec '%s'"), path);
144                 strbuf_release(&man_page);
145         }
146 }
147
148 static void exec_man_konqueror(const char *path, const char *page)
149 {
150         const char *display = getenv("DISPLAY");
151         if (display && *display) {
152                 struct strbuf man_page = STRBUF_INIT;
153                 const char *filename = "kfmclient";
154
155                 /* It's simpler to launch konqueror using kfmclient. */
156                 if (path) {
157                         size_t len;
158                         if (strip_suffix(path, "/konqueror", &len))
159                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
160                         filename = basename((char *)path);
161                 } else
162                         path = "kfmclient";
163                 strbuf_addf(&man_page, "man:%s(1)", page);
164                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
165                 warning_errno(_("failed to exec '%s'"), path);
166                 strbuf_release(&man_page);
167         }
168 }
169
170 static void exec_man_man(const char *path, const char *page)
171 {
172         if (!path)
173                 path = "man";
174         execlp(path, "man", page, (char *)NULL);
175         warning_errno(_("failed to exec '%s'"), path);
176 }
177
178 static void exec_man_cmd(const char *cmd, const char *page)
179 {
180         struct strbuf shell_cmd = STRBUF_INIT;
181         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
182         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
183         warning(_("failed to exec '%s'"), cmd);
184         strbuf_release(&shell_cmd);
185 }
186
187 static void add_man_viewer(const char *name)
188 {
189         struct man_viewer_list **p = &man_viewer_list;
190
191         while (*p)
192                 p = &((*p)->next);
193         FLEX_ALLOC_STR(*p, name, name);
194 }
195
196 static int supported_man_viewer(const char *name, size_t len)
197 {
198         return (!strncasecmp("man", name, len) ||
199                 !strncasecmp("woman", name, len) ||
200                 !strncasecmp("konqueror", name, len));
201 }
202
203 static void do_add_man_viewer_info(const char *name,
204                                    size_t len,
205                                    const char *value)
206 {
207         struct man_viewer_info_list *new_man_viewer;
208         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
209         new_man_viewer->info = xstrdup(value);
210         new_man_viewer->next = man_viewer_info_list;
211         man_viewer_info_list = new_man_viewer;
212 }
213
214 static int add_man_viewer_path(const char *name,
215                                size_t len,
216                                const char *value)
217 {
218         if (supported_man_viewer(name, len))
219                 do_add_man_viewer_info(name, len, value);
220         else
221                 warning(_("'%s': path for unsupported man viewer.\n"
222                           "Please consider using 'man.<tool>.cmd' instead."),
223                         name);
224
225         return 0;
226 }
227
228 static int add_man_viewer_cmd(const char *name,
229                               size_t len,
230                               const char *value)
231 {
232         if (supported_man_viewer(name, len))
233                 warning(_("'%s': cmd for supported man viewer.\n"
234                           "Please consider using 'man.<tool>.path' instead."),
235                         name);
236         else
237                 do_add_man_viewer_info(name, len, value);
238
239         return 0;
240 }
241
242 static int add_man_viewer_info(const char *var, const char *value)
243 {
244         const char *name, *subkey;
245         int namelen;
246
247         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
248                 return 0;
249
250         if (!strcmp(subkey, "path")) {
251                 if (!value)
252                         return config_error_nonbool(var);
253                 return add_man_viewer_path(name, namelen, value);
254         }
255         if (!strcmp(subkey, "cmd")) {
256                 if (!value)
257                         return config_error_nonbool(var);
258                 return add_man_viewer_cmd(name, namelen, value);
259         }
260
261         return 0;
262 }
263
264 static int git_help_config(const char *var, const char *value, void *cb)
265 {
266         if (starts_with(var, "column."))
267                 return git_column_config(var, value, "help", &colopts);
268         if (!strcmp(var, "help.format")) {
269                 if (!value)
270                         return config_error_nonbool(var);
271                 help_format = parse_help_format(value);
272                 return 0;
273         }
274         if (!strcmp(var, "help.htmlpath")) {
275                 if (!value)
276                         return config_error_nonbool(var);
277                 html_path = xstrdup(value);
278                 return 0;
279         }
280         if (!strcmp(var, "man.viewer")) {
281                 if (!value)
282                         return config_error_nonbool(var);
283                 add_man_viewer(value);
284                 return 0;
285         }
286         if (starts_with(var, "man."))
287                 return add_man_viewer_info(var, value);
288
289         return git_default_config(var, value, cb);
290 }
291
292 static struct cmdnames main_cmds, other_cmds;
293
294 static int is_git_command(const char *s)
295 {
296         if (is_builtin(s))
297                 return 1;
298
299         load_command_list("git-", &main_cmds, &other_cmds);
300         return is_in_cmdlist(&main_cmds, s) ||
301                 is_in_cmdlist(&other_cmds, s);
302 }
303
304 static const char *cmd_to_page(const char *git_cmd)
305 {
306         if (!git_cmd)
307                 return "git";
308         else if (starts_with(git_cmd, "git"))
309                 return git_cmd;
310         else if (is_git_command(git_cmd))
311                 return xstrfmt("git-%s", git_cmd);
312         else
313                 return xstrfmt("git%s", git_cmd);
314 }
315
316 static void setup_man_path(void)
317 {
318         struct strbuf new_path = STRBUF_INIT;
319         const char *old_path = getenv("MANPATH");
320         char *git_man_path = system_path(GIT_MAN_PATH);
321
322         /* We should always put ':' after our path. If there is no
323          * old_path, the ':' at the end will let 'man' to try
324          * system-wide paths after ours to find the manual page. If
325          * there is old_path, we need ':' as delimiter. */
326         strbuf_addstr(&new_path, git_man_path);
327         strbuf_addch(&new_path, ':');
328         if (old_path)
329                 strbuf_addstr(&new_path, old_path);
330
331         free(git_man_path);
332         setenv("MANPATH", new_path.buf, 1);
333
334         strbuf_release(&new_path);
335 }
336
337 static void exec_viewer(const char *name, const char *page)
338 {
339         const char *info = get_man_viewer_info(name);
340
341         if (!strcasecmp(name, "man"))
342                 exec_man_man(info, page);
343         else if (!strcasecmp(name, "woman"))
344                 exec_woman_emacs(info, page);
345         else if (!strcasecmp(name, "konqueror"))
346                 exec_man_konqueror(info, page);
347         else if (info)
348                 exec_man_cmd(info, page);
349         else
350                 warning(_("'%s': unknown man viewer."), name);
351 }
352
353 static void show_man_page(const char *git_cmd)
354 {
355         struct man_viewer_list *viewer;
356         const char *page = cmd_to_page(git_cmd);
357         const char *fallback = getenv("GIT_MAN_VIEWER");
358
359         setup_man_path();
360         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
361         {
362                 exec_viewer(viewer->name, page); /* will return when unable */
363         }
364         if (fallback)
365                 exec_viewer(fallback, page);
366         exec_viewer("man", page);
367         die(_("no man viewer handled the request"));
368 }
369
370 static void show_info_page(const char *git_cmd)
371 {
372         const char *page = cmd_to_page(git_cmd);
373         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
374         execlp("info", "info", "gitman", page, (char *)NULL);
375         die(_("no info viewer handled the request"));
376 }
377
378 static void get_html_page_path(struct strbuf *page_path, const char *page)
379 {
380         struct stat st;
381         char *to_free = NULL;
382
383         if (!html_path)
384                 html_path = to_free = system_path(GIT_HTML_PATH);
385
386         /* Check that we have a git documentation directory. */
387         if (!strstr(html_path, "://")) {
388                 if (stat(mkpath("%s/git.html", html_path), &st)
389                     || !S_ISREG(st.st_mode))
390                         die("'%s': not a documentation directory.", html_path);
391         }
392
393         strbuf_init(page_path, 0);
394         strbuf_addf(page_path, "%s/%s.html", html_path, page);
395         free(to_free);
396 }
397
398 static void open_html(const char *path)
399 {
400         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
401 }
402
403 static void show_html_page(const char *git_cmd)
404 {
405         const char *page = cmd_to_page(git_cmd);
406         struct strbuf page_path; /* it leaks but we exec bellow */
407
408         get_html_page_path(&page_path, page);
409
410         open_html(page_path.buf);
411 }
412
413 static const char *check_git_cmd(const char* cmd)
414 {
415         char *alias;
416
417         if (is_git_command(cmd))
418                 return cmd;
419
420         alias = alias_lookup(cmd);
421         if (alias) {
422                 const char **argv;
423                 int count;
424
425                 /*
426                  * handle_builtin() in git.c rewrites "git cmd --help"
427                  * to "git help --exclude-guides cmd", so we can use
428                  * exclude_guides to distinguish "git cmd --help" from
429                  * "git help cmd". In the latter case, or if cmd is an
430                  * alias for a shell command, just print the alias
431                  * definition.
432                  */
433                 if (!exclude_guides || alias[0] == '!') {
434                         printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
435                         free(alias);
436                         exit(0);
437                 }
438                 /*
439                  * Otherwise, we pretend that the command was "git
440                  * word0 --help". We use split_cmdline() to get the
441                  * first word of the alias, to ensure that we use the
442                  * same rules as when the alias is actually
443                  * used. split_cmdline() modifies alias in-place.
444                  */
445                 fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
446                 count = split_cmdline(alias, &argv);
447                 if (count < 0)
448                         die(_("bad alias.%s string: %s"), cmd,
449                             split_cmdline_strerror(count));
450                 free(argv);
451                 UNLEAK(alias);
452                 return alias;
453         }
454
455         if (exclude_guides)
456                 return help_unknown_cmd(cmd);
457
458         return cmd;
459 }
460
461 int cmd_help(int argc, const char **argv, const char *prefix)
462 {
463         int nongit;
464         enum help_format parsed_help_format;
465
466         argc = parse_options(argc, argv, prefix, builtin_help_options,
467                         builtin_help_usage, 0);
468         parsed_help_format = help_format;
469
470         if (show_all) {
471                 git_config(git_help_config, NULL);
472                 if (verbose) {
473                         setup_pager();
474                         list_all_cmds_help();
475                         return 0;
476                 }
477                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
478                 load_command_list("git-", &main_cmds, &other_cmds);
479                 list_commands(colopts, &main_cmds, &other_cmds);
480         }
481
482         if (show_config) {
483                 int for_human = show_config == 1;
484
485                 if (!for_human) {
486                         list_config_help(for_human);
487                         return 0;
488                 }
489                 setup_pager();
490                 list_config_help(for_human);
491                 printf("\n%s\n", _("'git help config' for more information"));
492                 return 0;
493         }
494
495         if (show_guides)
496                 list_common_guides_help();
497
498         if (show_all || show_guides) {
499                 printf("%s\n", _(git_more_info_string));
500                 /*
501                 * We're done. Ignore any remaining args
502                 */
503                 return 0;
504         }
505
506         if (!argv[0]) {
507                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
508                 list_common_cmds_help();
509                 printf("\n%s\n", _(git_more_info_string));
510                 return 0;
511         }
512
513         setup_git_directory_gently(&nongit);
514         git_config(git_help_config, NULL);
515
516         if (parsed_help_format != HELP_FORMAT_NONE)
517                 help_format = parsed_help_format;
518         if (help_format == HELP_FORMAT_NONE)
519                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
520
521         argv[0] = check_git_cmd(argv[0]);
522
523         switch (help_format) {
524         case HELP_FORMAT_NONE:
525         case HELP_FORMAT_MAN:
526                 show_man_page(argv[0]);
527                 break;
528         case HELP_FORMAT_INFO:
529                 show_info_page(argv[0]);
530                 break;
531         case HELP_FORMAT_WEB:
532                 show_html_page(argv[0]);
533                 break;
534         }
535
536         return 0;
537 }