Merge branch 'maint'
[git] / builtin / help.c
1 /*
2  * builtin-help.c
3  *
4  * Builtin help command
5  */
6 #include "cache.h"
7 #include "builtin.h"
8 #include "exec_cmd.h"
9 #include "common-cmds.h"
10 #include "parse-options.h"
11 #include "run-command.h"
12 #include "column.h"
13 #include "help.h"
14
15 #ifndef DEFAULT_HELP_FORMAT
16 #define DEFAULT_HELP_FORMAT "man"
17 #endif
18
19 static struct man_viewer_list {
20         struct man_viewer_list *next;
21         char name[FLEX_ARRAY];
22 } *man_viewer_list;
23
24 static struct man_viewer_info_list {
25         struct man_viewer_info_list *next;
26         const char *info;
27         char name[FLEX_ARRAY];
28 } *man_viewer_info_list;
29
30 enum help_format {
31         HELP_FORMAT_NONE,
32         HELP_FORMAT_MAN,
33         HELP_FORMAT_INFO,
34         HELP_FORMAT_WEB
35 };
36
37 static const char *html_path;
38
39 static int show_all = 0;
40 static unsigned int colopts;
41 static enum help_format help_format = HELP_FORMAT_NONE;
42 static struct option builtin_help_options[] = {
43         OPT_BOOLEAN('a', "all", &show_all, N_("print all available commands")),
44         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
45         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
46                         HELP_FORMAT_WEB),
47         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
48                         HELP_FORMAT_INFO),
49         OPT_END(),
50 };
51
52 static const char * const builtin_help_usage[] = {
53         N_("git help [--all] [--man|--web|--info] [command]"),
54         NULL
55 };
56
57 static enum help_format parse_help_format(const char *format)
58 {
59         if (!strcmp(format, "man"))
60                 return HELP_FORMAT_MAN;
61         if (!strcmp(format, "info"))
62                 return HELP_FORMAT_INFO;
63         if (!strcmp(format, "web") || !strcmp(format, "html"))
64                 return HELP_FORMAT_WEB;
65         die(_("unrecognized help format '%s'"), format);
66 }
67
68 static const char *get_man_viewer_info(const char *name)
69 {
70         struct man_viewer_info_list *viewer;
71
72         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
73         {
74                 if (!strcasecmp(name, viewer->name))
75                         return viewer->info;
76         }
77         return NULL;
78 }
79
80 static int check_emacsclient_version(void)
81 {
82         struct strbuf buffer = STRBUF_INIT;
83         struct child_process ec_process;
84         const char *argv_ec[] = { "emacsclient", "--version", NULL };
85         int version;
86
87         /* emacsclient prints its version number on stderr */
88         memset(&ec_process, 0, sizeof(ec_process));
89         ec_process.argv = argv_ec;
90         ec_process.err = -1;
91         ec_process.stdout_to_stderr = 1;
92         if (start_command(&ec_process))
93                 return error(_("Failed to start emacsclient."));
94
95         strbuf_read(&buffer, ec_process.err, 20);
96         close(ec_process.err);
97
98         /*
99          * Don't bother checking return value, because "emacsclient --version"
100          * seems to always exits with code 1.
101          */
102         finish_command(&ec_process);
103
104         if (prefixcmp(buffer.buf, "emacsclient")) {
105                 strbuf_release(&buffer);
106                 return error(_("Failed to parse emacsclient version."));
107         }
108
109         strbuf_remove(&buffer, 0, strlen("emacsclient"));
110         version = atoi(buffer.buf);
111
112         if (version < 22) {
113                 strbuf_release(&buffer);
114                 return error(_("emacsclient version '%d' too old (< 22)."),
115                         version);
116         }
117
118         strbuf_release(&buffer);
119         return 0;
120 }
121
122 static void exec_woman_emacs(const char *path, const char *page)
123 {
124         if (!check_emacsclient_version()) {
125                 /* This works only with emacsclient version >= 22. */
126                 struct strbuf man_page = STRBUF_INIT;
127
128                 if (!path)
129                         path = "emacsclient";
130                 strbuf_addf(&man_page, "(woman \"%s\")", page);
131                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
132                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
133         }
134 }
135
136 static void exec_man_konqueror(const char *path, const char *page)
137 {
138         const char *display = getenv("DISPLAY");
139         if (display && *display) {
140                 struct strbuf man_page = STRBUF_INIT;
141                 const char *filename = "kfmclient";
142
143                 /* It's simpler to launch konqueror using kfmclient. */
144                 if (path) {
145                         const char *file = strrchr(path, '/');
146                         if (file && !strcmp(file + 1, "konqueror")) {
147                                 char *new = xstrdup(path);
148                                 char *dest = strrchr(new, '/');
149
150                                 /* strlen("konqueror") == strlen("kfmclient") */
151                                 strcpy(dest + 1, "kfmclient");
152                                 path = new;
153                         }
154                         if (file)
155                                 filename = file;
156                 } else
157                         path = "kfmclient";
158                 strbuf_addf(&man_page, "man:%s(1)", page);
159                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
160                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
161         }
162 }
163
164 static void exec_man_man(const char *path, const char *page)
165 {
166         if (!path)
167                 path = "man";
168         execlp(path, "man", page, (char *)NULL);
169         warning(_("failed to exec '%s': %s"), path, strerror(errno));
170 }
171
172 static void exec_man_cmd(const char *cmd, const char *page)
173 {
174         struct strbuf shell_cmd = STRBUF_INIT;
175         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
176         execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
177         warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
178 }
179
180 static void add_man_viewer(const char *name)
181 {
182         struct man_viewer_list **p = &man_viewer_list;
183         size_t len = strlen(name);
184
185         while (*p)
186                 p = &((*p)->next);
187         *p = xcalloc(1, (sizeof(**p) + len + 1));
188         strncpy((*p)->name, name, len);
189 }
190
191 static int supported_man_viewer(const char *name, size_t len)
192 {
193         return (!strncasecmp("man", name, len) ||
194                 !strncasecmp("woman", name, len) ||
195                 !strncasecmp("konqueror", name, len));
196 }
197
198 static void do_add_man_viewer_info(const char *name,
199                                    size_t len,
200                                    const char *value)
201 {
202         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
203
204         strncpy(new->name, name, len);
205         new->info = xstrdup(value);
206         new->next = man_viewer_info_list;
207         man_viewer_info_list = new;
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 = var + 4;
241         const char *subkey = strrchr(name, '.');
242
243         if (!subkey)
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, subkey - name, value);
250         }
251         if (!strcmp(subkey, ".cmd")) {
252                 if (!value)
253                         return config_error_nonbool(var);
254                 return add_man_viewer_cmd(name, subkey - name, 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 (!prefixcmp(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 (!prefixcmp(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 void list_common_cmds_help(void)
291 {
292         int i, longest = 0;
293
294         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
295                 if (longest < strlen(common_cmds[i].name))
296                         longest = strlen(common_cmds[i].name);
297         }
298
299         puts(_("The most commonly used git commands are:"));
300         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
301                 printf("   %s   ", common_cmds[i].name);
302                 mput_char(' ', longest - strlen(common_cmds[i].name));
303                 puts(_(common_cmds[i].help));
304         }
305 }
306
307 static int is_git_command(const char *s)
308 {
309         return is_in_cmdlist(&main_cmds, s) ||
310                 is_in_cmdlist(&other_cmds, s);
311 }
312
313 static const char *prepend(const char *prefix, const char *cmd)
314 {
315         size_t pre_len = strlen(prefix);
316         size_t cmd_len = strlen(cmd);
317         char *p = xmalloc(pre_len + cmd_len + 1);
318         memcpy(p, prefix, pre_len);
319         strcpy(p + pre_len, cmd);
320         return p;
321 }
322
323 static const char *cmd_to_page(const char *git_cmd)
324 {
325         if (!git_cmd)
326                 return "git";
327         else if (!prefixcmp(git_cmd, "git"))
328                 return git_cmd;
329         else if (is_git_command(git_cmd))
330                 return prepend("git-", git_cmd);
331         else
332                 return prepend("git", git_cmd);
333 }
334
335 static void setup_man_path(void)
336 {
337         struct strbuf new_path = STRBUF_INIT;
338         const char *old_path = getenv("MANPATH");
339
340         /* We should always put ':' after our path. If there is no
341          * old_path, the ':' at the end will let 'man' to try
342          * system-wide paths after ours to find the manual page. If
343          * there is old_path, we need ':' as delimiter. */
344         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
345         strbuf_addch(&new_path, ':');
346         if (old_path)
347                 strbuf_addstr(&new_path, old_path);
348
349         setenv("MANPATH", new_path.buf, 1);
350
351         strbuf_release(&new_path);
352 }
353
354 static void exec_viewer(const char *name, const char *page)
355 {
356         const char *info = get_man_viewer_info(name);
357
358         if (!strcasecmp(name, "man"))
359                 exec_man_man(info, page);
360         else if (!strcasecmp(name, "woman"))
361                 exec_woman_emacs(info, page);
362         else if (!strcasecmp(name, "konqueror"))
363                 exec_man_konqueror(info, page);
364         else if (info)
365                 exec_man_cmd(info, page);
366         else
367                 warning(_("'%s': unknown man viewer."), name);
368 }
369
370 static void show_man_page(const char *git_cmd)
371 {
372         struct man_viewer_list *viewer;
373         const char *page = cmd_to_page(git_cmd);
374         const char *fallback = getenv("GIT_MAN_VIEWER");
375
376         setup_man_path();
377         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
378         {
379                 exec_viewer(viewer->name, page); /* will return when unable */
380         }
381         if (fallback)
382                 exec_viewer(fallback, page);
383         exec_viewer("man", page);
384         die(_("no man viewer handled the request"));
385 }
386
387 static void show_info_page(const char *git_cmd)
388 {
389         const char *page = cmd_to_page(git_cmd);
390         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
391         execlp("info", "info", "gitman", page, (char *)NULL);
392         die(_("no info viewer handled the request"));
393 }
394
395 static void get_html_page_path(struct strbuf *page_path, const char *page)
396 {
397         struct stat st;
398         if (!html_path)
399                 html_path = system_path(GIT_HTML_PATH);
400
401         /* Check that we have a git documentation directory. */
402         if (!strstr(html_path, "://")) {
403                 if (stat(mkpath("%s/git.html", html_path), &st)
404                     || !S_ISREG(st.st_mode))
405                         die("'%s': not a documentation directory.", html_path);
406         }
407
408         strbuf_init(page_path, 0);
409         strbuf_addf(page_path, "%s/%s.html", html_path, page);
410 }
411
412 /*
413  * If open_html is not defined in a platform-specific way (see for
414  * example compat/mingw.h), we use the script web--browse to display
415  * HTML.
416  */
417 #ifndef open_html
418 static void open_html(const char *path)
419 {
420         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
421 }
422 #endif
423
424 static void show_html_page(const char *git_cmd)
425 {
426         const char *page = cmd_to_page(git_cmd);
427         struct strbuf page_path; /* it leaks but we exec bellow */
428
429         get_html_page_path(&page_path, page);
430
431         open_html(page_path.buf);
432 }
433
434 int cmd_help(int argc, const char **argv, const char *prefix)
435 {
436         int nongit;
437         const char *alias;
438         enum help_format parsed_help_format;
439         load_command_list("git-", &main_cmds, &other_cmds);
440
441         argc = parse_options(argc, argv, prefix, builtin_help_options,
442                         builtin_help_usage, 0);
443         parsed_help_format = help_format;
444
445         if (show_all) {
446                 git_config(git_help_config, NULL);
447                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
448                 list_commands(colopts, &main_cmds, &other_cmds);
449                 printf("%s\n", _(git_more_info_string));
450                 return 0;
451         }
452
453         if (!argv[0]) {
454                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
455                 list_common_cmds_help();
456                 printf("\n%s\n", _(git_more_info_string));
457                 return 0;
458         }
459
460         setup_git_directory_gently(&nongit);
461         git_config(git_help_config, NULL);
462
463         if (parsed_help_format != HELP_FORMAT_NONE)
464                 help_format = parsed_help_format;
465         if (help_format == HELP_FORMAT_NONE)
466                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
467
468         alias = alias_lookup(argv[0]);
469         if (alias && !is_git_command(argv[0])) {
470                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
471                 return 0;
472         }
473
474         switch (help_format) {
475         case HELP_FORMAT_NONE:
476         case HELP_FORMAT_MAN:
477                 show_man_page(argv[0]);
478                 break;
479         case HELP_FORMAT_INFO:
480                 show_info_page(argv[0]);
481                 break;
482         case HELP_FORMAT_WEB:
483                 show_html_page(argv[0]);
484                 break;
485         }
486
487         return 0;
488 }