Merge branch 'js/xread-in-full'
[git] / builtin / help.c
1 /*
2  * Builtin help command
3  */
4 #include "cache.h"
5 #include "builtin.h"
6 #include "exec_cmd.h"
7 #include "parse-options.h"
8 #include "run-command.h"
9 #include "column.h"
10 #include "help.h"
11
12 #ifndef DEFAULT_HELP_FORMAT
13 #define DEFAULT_HELP_FORMAT "man"
14 #endif
15
16 static struct man_viewer_list {
17         struct man_viewer_list *next;
18         char name[FLEX_ARRAY];
19 } *man_viewer_list;
20
21 static struct man_viewer_info_list {
22         struct man_viewer_info_list *next;
23         const char *info;
24         char name[FLEX_ARRAY];
25 } *man_viewer_info_list;
26
27 enum help_format {
28         HELP_FORMAT_NONE,
29         HELP_FORMAT_MAN,
30         HELP_FORMAT_INFO,
31         HELP_FORMAT_WEB
32 };
33
34 static const char *html_path;
35
36 static int show_all = 0;
37 static int show_guides = 0;
38 static unsigned int colopts;
39 static enum help_format help_format = HELP_FORMAT_NONE;
40 static struct option builtin_help_options[] = {
41         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
42         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
43         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
44         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
45                         HELP_FORMAT_WEB),
46         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
47                         HELP_FORMAT_INFO),
48         OPT_END(),
49 };
50
51 static const char * const builtin_help_usage[] = {
52         N_("git help [--all] [--guides] [--man|--web|--info] [command]"),
53         NULL
54 };
55
56 static enum help_format parse_help_format(const char *format)
57 {
58         if (!strcmp(format, "man"))
59                 return HELP_FORMAT_MAN;
60         if (!strcmp(format, "info"))
61                 return HELP_FORMAT_INFO;
62         if (!strcmp(format, "web") || !strcmp(format, "html"))
63                 return HELP_FORMAT_WEB;
64         die(_("unrecognized help format '%s'"), format);
65 }
66
67 static const char *get_man_viewer_info(const char *name)
68 {
69         struct man_viewer_info_list *viewer;
70
71         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
72         {
73                 if (!strcasecmp(name, viewer->name))
74                         return viewer->info;
75         }
76         return NULL;
77 }
78
79 static int check_emacsclient_version(void)
80 {
81         struct strbuf buffer = STRBUF_INIT;
82         struct child_process ec_process;
83         const char *argv_ec[] = { "emacsclient", "--version", NULL };
84         int version;
85
86         /* emacsclient prints its version number on stderr */
87         memset(&ec_process, 0, sizeof(ec_process));
88         ec_process.argv = argv_ec;
89         ec_process.err = -1;
90         ec_process.stdout_to_stderr = 1;
91         if (start_command(&ec_process))
92                 return error(_("Failed to start emacsclient."));
93
94         strbuf_read(&buffer, ec_process.err, 20);
95         close(ec_process.err);
96
97         /*
98          * Don't bother checking return value, because "emacsclient --version"
99          * seems to always exits with code 1.
100          */
101         finish_command(&ec_process);
102
103         if (prefixcmp(buffer.buf, "emacsclient")) {
104                 strbuf_release(&buffer);
105                 return error(_("Failed to parse emacsclient version."));
106         }
107
108         strbuf_remove(&buffer, 0, strlen("emacsclient"));
109         version = atoi(buffer.buf);
110
111         if (version < 22) {
112                 strbuf_release(&buffer);
113                 return error(_("emacsclient version '%d' too old (< 22)."),
114                         version);
115         }
116
117         strbuf_release(&buffer);
118         return 0;
119 }
120
121 static void exec_woman_emacs(const char *path, const char *page)
122 {
123         if (!check_emacsclient_version()) {
124                 /* This works only with emacsclient version >= 22. */
125                 struct strbuf man_page = STRBUF_INIT;
126
127                 if (!path)
128                         path = "emacsclient";
129                 strbuf_addf(&man_page, "(woman \"%s\")", page);
130                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
131                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
132         }
133 }
134
135 static void exec_man_konqueror(const char *path, const char *page)
136 {
137         const char *display = getenv("DISPLAY");
138         if (display && *display) {
139                 struct strbuf man_page = STRBUF_INIT;
140                 const char *filename = "kfmclient";
141
142                 /* It's simpler to launch konqueror using kfmclient. */
143                 if (path) {
144                         const char *file = strrchr(path, '/');
145                         if (file && !strcmp(file + 1, "konqueror")) {
146                                 char *new = xstrdup(path);
147                                 char *dest = strrchr(new, '/');
148
149                                 /* strlen("konqueror") == strlen("kfmclient") */
150                                 strcpy(dest + 1, "kfmclient");
151                                 path = new;
152                         }
153                         if (file)
154                                 filename = file;
155                 } else
156                         path = "kfmclient";
157                 strbuf_addf(&man_page, "man:%s(1)", page);
158                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
159                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
160         }
161 }
162
163 static void exec_man_man(const char *path, const char *page)
164 {
165         if (!path)
166                 path = "man";
167         execlp(path, "man", page, (char *)NULL);
168         warning(_("failed to exec '%s': %s"), path, strerror(errno));
169 }
170
171 static void exec_man_cmd(const char *cmd, const char *page)
172 {
173         struct strbuf shell_cmd = STRBUF_INIT;
174         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
175         execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
176         warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
177 }
178
179 static void add_man_viewer(const char *name)
180 {
181         struct man_viewer_list **p = &man_viewer_list;
182         size_t len = strlen(name);
183
184         while (*p)
185                 p = &((*p)->next);
186         *p = xcalloc(1, (sizeof(**p) + len + 1));
187         strncpy((*p)->name, name, len);
188 }
189
190 static int supported_man_viewer(const char *name, size_t len)
191 {
192         return (!strncasecmp("man", name, len) ||
193                 !strncasecmp("woman", name, len) ||
194                 !strncasecmp("konqueror", name, len));
195 }
196
197 static void do_add_man_viewer_info(const char *name,
198                                    size_t len,
199                                    const char *value)
200 {
201         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
202
203         strncpy(new->name, name, len);
204         new->info = xstrdup(value);
205         new->next = man_viewer_info_list;
206         man_viewer_info_list = new;
207 }
208
209 static int add_man_viewer_path(const char *name,
210                                size_t len,
211                                const char *value)
212 {
213         if (supported_man_viewer(name, len))
214                 do_add_man_viewer_info(name, len, value);
215         else
216                 warning(_("'%s': path for unsupported man viewer.\n"
217                           "Please consider using 'man.<tool>.cmd' instead."),
218                         name);
219
220         return 0;
221 }
222
223 static int add_man_viewer_cmd(const char *name,
224                               size_t len,
225                               const char *value)
226 {
227         if (supported_man_viewer(name, len))
228                 warning(_("'%s': cmd for supported man viewer.\n"
229                           "Please consider using 'man.<tool>.path' instead."),
230                         name);
231         else
232                 do_add_man_viewer_info(name, len, value);
233
234         return 0;
235 }
236
237 static int add_man_viewer_info(const char *var, const char *value)
238 {
239         const char *name, *subkey;
240         int namelen;
241
242         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
243                 return 0;
244
245         if (!strcmp(subkey, "path")) {
246                 if (!value)
247                         return config_error_nonbool(var);
248                 return add_man_viewer_path(name, namelen, value);
249         }
250         if (!strcmp(subkey, "cmd")) {
251                 if (!value)
252                         return config_error_nonbool(var);
253                 return add_man_viewer_cmd(name, namelen, value);
254         }
255
256         return 0;
257 }
258
259 static int git_help_config(const char *var, const char *value, void *cb)
260 {
261         if (!prefixcmp(var, "column."))
262                 return git_column_config(var, value, "help", &colopts);
263         if (!strcmp(var, "help.format")) {
264                 if (!value)
265                         return config_error_nonbool(var);
266                 help_format = parse_help_format(value);
267                 return 0;
268         }
269         if (!strcmp(var, "help.htmlpath")) {
270                 if (!value)
271                         return config_error_nonbool(var);
272                 html_path = xstrdup(value);
273                 return 0;
274         }
275         if (!strcmp(var, "man.viewer")) {
276                 if (!value)
277                         return config_error_nonbool(var);
278                 add_man_viewer(value);
279                 return 0;
280         }
281         if (!prefixcmp(var, "man."))
282                 return add_man_viewer_info(var, value);
283
284         return git_default_config(var, value, cb);
285 }
286
287 static struct cmdnames main_cmds, other_cmds;
288
289 static int is_git_command(const char *s)
290 {
291         return is_in_cmdlist(&main_cmds, s) ||
292                 is_in_cmdlist(&other_cmds, s);
293 }
294
295 static const char *prepend(const char *prefix, const char *cmd)
296 {
297         size_t pre_len = strlen(prefix);
298         size_t cmd_len = strlen(cmd);
299         char *p = xmalloc(pre_len + cmd_len + 1);
300         memcpy(p, prefix, pre_len);
301         strcpy(p + pre_len, cmd);
302         return p;
303 }
304
305 static const char *cmd_to_page(const char *git_cmd)
306 {
307         if (!git_cmd)
308                 return "git";
309         else if (!prefixcmp(git_cmd, "git"))
310                 return git_cmd;
311         else if (is_git_command(git_cmd))
312                 return prepend("git-", git_cmd);
313         else
314                 return prepend("git", git_cmd);
315 }
316
317 static void setup_man_path(void)
318 {
319         struct strbuf new_path = STRBUF_INIT;
320         const char *old_path = getenv("MANPATH");
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, system_path(GIT_MAN_PATH));
327         strbuf_addch(&new_path, ':');
328         if (old_path)
329                 strbuf_addstr(&new_path, old_path);
330
331         setenv("MANPATH", new_path.buf, 1);
332
333         strbuf_release(&new_path);
334 }
335
336 static void exec_viewer(const char *name, const char *page)
337 {
338         const char *info = get_man_viewer_info(name);
339
340         if (!strcasecmp(name, "man"))
341                 exec_man_man(info, page);
342         else if (!strcasecmp(name, "woman"))
343                 exec_woman_emacs(info, page);
344         else if (!strcasecmp(name, "konqueror"))
345                 exec_man_konqueror(info, page);
346         else if (info)
347                 exec_man_cmd(info, page);
348         else
349                 warning(_("'%s': unknown man viewer."), name);
350 }
351
352 static void show_man_page(const char *git_cmd)
353 {
354         struct man_viewer_list *viewer;
355         const char *page = cmd_to_page(git_cmd);
356         const char *fallback = getenv("GIT_MAN_VIEWER");
357
358         setup_man_path();
359         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
360         {
361                 exec_viewer(viewer->name, page); /* will return when unable */
362         }
363         if (fallback)
364                 exec_viewer(fallback, page);
365         exec_viewer("man", page);
366         die(_("no man viewer handled the request"));
367 }
368
369 static void show_info_page(const char *git_cmd)
370 {
371         const char *page = cmd_to_page(git_cmd);
372         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
373         execlp("info", "info", "gitman", page, (char *)NULL);
374         die(_("no info viewer handled the request"));
375 }
376
377 static void get_html_page_path(struct strbuf *page_path, const char *page)
378 {
379         struct stat st;
380         if (!html_path)
381                 html_path = system_path(GIT_HTML_PATH);
382
383         /* Check that we have a git documentation directory. */
384         if (!strstr(html_path, "://")) {
385                 if (stat(mkpath("%s/git.html", html_path), &st)
386                     || !S_ISREG(st.st_mode))
387                         die("'%s': not a documentation directory.", html_path);
388         }
389
390         strbuf_init(page_path, 0);
391         strbuf_addf(page_path, "%s/%s.html", html_path, page);
392 }
393
394 /*
395  * If open_html is not defined in a platform-specific way (see for
396  * example compat/mingw.h), we use the script web--browse to display
397  * HTML.
398  */
399 #ifndef open_html
400 static void open_html(const char *path)
401 {
402         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
403 }
404 #endif
405
406 static void show_html_page(const char *git_cmd)
407 {
408         const char *page = cmd_to_page(git_cmd);
409         struct strbuf page_path; /* it leaks but we exec bellow */
410
411         get_html_page_path(&page_path, page);
412
413         open_html(page_path.buf);
414 }
415
416 static struct {
417         const char *name;
418         const char *help;
419 } common_guides[] = {
420         { "attributes", N_("Defining attributes per path") },
421         { "glossary", N_("A Git glossary") },
422         { "ignore", N_("Specifies intentionally untracked files to ignore") },
423         { "modules", N_("Defining submodule properties") },
424         { "revisions", N_("Specifying revisions and ranges for Git") },
425         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
426         { "workflows", N_("An overview of recommended workflows with Git") },
427 };
428
429 static void list_common_guides_help(void)
430 {
431         int i, longest = 0;
432
433         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
434                 if (longest < strlen(common_guides[i].name))
435                         longest = strlen(common_guides[i].name);
436         }
437
438         puts(_("The common Git guides are:\n"));
439         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
440                 printf("   %s   ", common_guides[i].name);
441                 mput_char(' ', longest - strlen(common_guides[i].name));
442                 puts(_(common_guides[i].help));
443         }
444         putchar('\n');
445 }
446
447 int cmd_help(int argc, const char **argv, const char *prefix)
448 {
449         int nongit;
450         const char *alias;
451         enum help_format parsed_help_format;
452         load_command_list("git-", &main_cmds, &other_cmds);
453
454         argc = parse_options(argc, argv, prefix, builtin_help_options,
455                         builtin_help_usage, 0);
456         parsed_help_format = help_format;
457
458         if (show_all) {
459                 git_config(git_help_config, NULL);
460                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
461                 list_commands(colopts, &main_cmds, &other_cmds);
462         }
463
464         if (show_guides)
465                 list_common_guides_help();
466
467         if (show_all || show_guides) {
468                 printf("%s\n", _(git_more_info_string));
469                 /*
470                 * We're done. Ignore any remaining args
471                 */
472                 return 0;
473         }
474
475         if (!argv[0]) {
476                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
477                 list_common_cmds_help();
478                 printf("\n%s\n", _(git_more_info_string));
479                 return 0;
480         }
481
482         setup_git_directory_gently(&nongit);
483         git_config(git_help_config, NULL);
484
485         if (parsed_help_format != HELP_FORMAT_NONE)
486                 help_format = parsed_help_format;
487         if (help_format == HELP_FORMAT_NONE)
488                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
489
490         alias = alias_lookup(argv[0]);
491         if (alias && !is_git_command(argv[0])) {
492                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
493                 return 0;
494         }
495
496         switch (help_format) {
497         case HELP_FORMAT_NONE:
498         case HELP_FORMAT_MAN:
499                 show_man_page(argv[0]);
500                 break;
501         case HELP_FORMAT_INFO:
502                 show_info_page(argv[0]);
503                 break;
504         case HELP_FORMAT_WEB:
505                 show_html_page(argv[0]);
506                 break;
507         }
508
509         return 0;
510 }