Merge branch 'jt/fast-export-copy-modify-fix' into maint
[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
13 #ifndef DEFAULT_HELP_FORMAT
14 #define DEFAULT_HELP_FORMAT "man"
15 #endif
16
17 static struct man_viewer_list {
18         struct man_viewer_list *next;
19         char name[FLEX_ARRAY];
20 } *man_viewer_list;
21
22 static struct man_viewer_info_list {
23         struct man_viewer_info_list *next;
24         const char *info;
25         char name[FLEX_ARRAY];
26 } *man_viewer_info_list;
27
28 enum help_format {
29         HELP_FORMAT_NONE,
30         HELP_FORMAT_MAN,
31         HELP_FORMAT_INFO,
32         HELP_FORMAT_WEB
33 };
34
35 static const char *html_path;
36
37 static int show_all = 0;
38 static int show_guides = 0;
39 static unsigned int colopts;
40 static enum help_format help_format = HELP_FORMAT_NONE;
41 static int exclude_guides;
42 static struct option builtin_help_options[] = {
43         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
44         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
45         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
46         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
47         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
48                         HELP_FORMAT_WEB),
49         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
50                         HELP_FORMAT_INFO),
51         OPT_END(),
52 };
53
54 static const char * const builtin_help_usage[] = {
55         N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
56         NULL
57 };
58
59 static enum help_format parse_help_format(const char *format)
60 {
61         if (!strcmp(format, "man"))
62                 return HELP_FORMAT_MAN;
63         if (!strcmp(format, "info"))
64                 return HELP_FORMAT_INFO;
65         if (!strcmp(format, "web") || !strcmp(format, "html"))
66                 return HELP_FORMAT_WEB;
67         die(_("unrecognized help format '%s'"), format);
68 }
69
70 static const char *get_man_viewer_info(const char *name)
71 {
72         struct man_viewer_info_list *viewer;
73
74         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
75         {
76                 if (!strcasecmp(name, viewer->name))
77                         return viewer->info;
78         }
79         return NULL;
80 }
81
82 static int check_emacsclient_version(void)
83 {
84         struct strbuf buffer = STRBUF_INIT;
85         struct child_process ec_process = CHILD_PROCESS_INIT;
86         const char *argv_ec[] = { "emacsclient", "--version", NULL };
87         int version;
88
89         /* emacsclient prints its version number on stderr */
90         ec_process.argv = argv_ec;
91         ec_process.err = -1;
92         ec_process.stdout_to_stderr = 1;
93         if (start_command(&ec_process))
94                 return error(_("Failed to start emacsclient."));
95
96         strbuf_read(&buffer, ec_process.err, 20);
97         close(ec_process.err);
98
99         /*
100          * Don't bother checking return value, because "emacsclient --version"
101          * seems to always exits with code 1.
102          */
103         finish_command(&ec_process);
104
105         if (!starts_with(buffer.buf, "emacsclient")) {
106                 strbuf_release(&buffer);
107                 return error(_("Failed to parse emacsclient version."));
108         }
109
110         strbuf_remove(&buffer, 0, strlen("emacsclient"));
111         version = atoi(buffer.buf);
112
113         if (version < 22) {
114                 strbuf_release(&buffer);
115                 return error(_("emacsclient version '%d' too old (< 22)."),
116                         version);
117         }
118
119         strbuf_release(&buffer);
120         return 0;
121 }
122
123 static void exec_woman_emacs(const char *path, const char *page)
124 {
125         if (!check_emacsclient_version()) {
126                 /* This works only with emacsclient version >= 22. */
127                 struct strbuf man_page = STRBUF_INIT;
128
129                 if (!path)
130                         path = "emacsclient";
131                 strbuf_addf(&man_page, "(woman \"%s\")", page);
132                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
133                 warning_errno(_("failed to exec '%s'"), path);
134         }
135 }
136
137 static void exec_man_konqueror(const char *path, const char *page)
138 {
139         const char *display = getenv("DISPLAY");
140         if (display && *display) {
141                 struct strbuf man_page = STRBUF_INIT;
142                 const char *filename = "kfmclient";
143
144                 /* It's simpler to launch konqueror using kfmclient. */
145                 if (path) {
146                         size_t len;
147                         if (strip_suffix(path, "/konqueror", &len))
148                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
149                         filename = basename((char *)path);
150                 } else
151                         path = "kfmclient";
152                 strbuf_addf(&man_page, "man:%s(1)", page);
153                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
154                 warning_errno(_("failed to exec '%s'"), path);
155         }
156 }
157
158 static void exec_man_man(const char *path, const char *page)
159 {
160         if (!path)
161                 path = "man";
162         execlp(path, "man", page, (char *)NULL);
163         warning_errno(_("failed to exec '%s'"), path);
164 }
165
166 static void exec_man_cmd(const char *cmd, const char *page)
167 {
168         struct strbuf shell_cmd = STRBUF_INIT;
169         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
170         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
171         warning(_("failed to exec '%s'"), cmd);
172 }
173
174 static void add_man_viewer(const char *name)
175 {
176         struct man_viewer_list **p = &man_viewer_list;
177
178         while (*p)
179                 p = &((*p)->next);
180         FLEX_ALLOC_STR(*p, name, name);
181 }
182
183 static int supported_man_viewer(const char *name, size_t len)
184 {
185         return (!strncasecmp("man", name, len) ||
186                 !strncasecmp("woman", name, len) ||
187                 !strncasecmp("konqueror", name, len));
188 }
189
190 static void do_add_man_viewer_info(const char *name,
191                                    size_t len,
192                                    const char *value)
193 {
194         struct man_viewer_info_list *new;
195         FLEX_ALLOC_MEM(new, name, name, len);
196         new->info = xstrdup(value);
197         new->next = man_viewer_info_list;
198         man_viewer_info_list = new;
199 }
200
201 static int add_man_viewer_path(const char *name,
202                                size_t len,
203                                const char *value)
204 {
205         if (supported_man_viewer(name, len))
206                 do_add_man_viewer_info(name, len, value);
207         else
208                 warning(_("'%s': path for unsupported man viewer.\n"
209                           "Please consider using 'man.<tool>.cmd' instead."),
210                         name);
211
212         return 0;
213 }
214
215 static int add_man_viewer_cmd(const char *name,
216                               size_t len,
217                               const char *value)
218 {
219         if (supported_man_viewer(name, len))
220                 warning(_("'%s': cmd for supported man viewer.\n"
221                           "Please consider using 'man.<tool>.path' instead."),
222                         name);
223         else
224                 do_add_man_viewer_info(name, len, value);
225
226         return 0;
227 }
228
229 static int add_man_viewer_info(const char *var, const char *value)
230 {
231         const char *name, *subkey;
232         int namelen;
233
234         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
235                 return 0;
236
237         if (!strcmp(subkey, "path")) {
238                 if (!value)
239                         return config_error_nonbool(var);
240                 return add_man_viewer_path(name, namelen, value);
241         }
242         if (!strcmp(subkey, "cmd")) {
243                 if (!value)
244                         return config_error_nonbool(var);
245                 return add_man_viewer_cmd(name, namelen, value);
246         }
247
248         return 0;
249 }
250
251 static int git_help_config(const char *var, const char *value, void *cb)
252 {
253         if (starts_with(var, "column."))
254                 return git_column_config(var, value, "help", &colopts);
255         if (!strcmp(var, "help.format")) {
256                 if (!value)
257                         return config_error_nonbool(var);
258                 help_format = parse_help_format(value);
259                 return 0;
260         }
261         if (!strcmp(var, "help.htmlpath")) {
262                 if (!value)
263                         return config_error_nonbool(var);
264                 html_path = xstrdup(value);
265                 return 0;
266         }
267         if (!strcmp(var, "man.viewer")) {
268                 if (!value)
269                         return config_error_nonbool(var);
270                 add_man_viewer(value);
271                 return 0;
272         }
273         if (starts_with(var, "man."))
274                 return add_man_viewer_info(var, value);
275
276         return git_default_config(var, value, cb);
277 }
278
279 static struct cmdnames main_cmds, other_cmds;
280
281 static int is_git_command(const char *s)
282 {
283         if (is_builtin(s))
284                 return 1;
285
286         load_command_list("git-", &main_cmds, &other_cmds);
287         return is_in_cmdlist(&main_cmds, s) ||
288                 is_in_cmdlist(&other_cmds, s);
289 }
290
291 static const char *cmd_to_page(const char *git_cmd)
292 {
293         if (!git_cmd)
294                 return "git";
295         else if (starts_with(git_cmd, "git"))
296                 return git_cmd;
297         else if (is_git_command(git_cmd))
298                 return xstrfmt("git-%s", git_cmd);
299         else
300                 return xstrfmt("git%s", git_cmd);
301 }
302
303 static void setup_man_path(void)
304 {
305         struct strbuf new_path = STRBUF_INIT;
306         const char *old_path = getenv("MANPATH");
307         char *git_man_path = system_path(GIT_MAN_PATH);
308
309         /* We should always put ':' after our path. If there is no
310          * old_path, the ':' at the end will let 'man' to try
311          * system-wide paths after ours to find the manual page. If
312          * there is old_path, we need ':' as delimiter. */
313         strbuf_addstr(&new_path, git_man_path);
314         strbuf_addch(&new_path, ':');
315         if (old_path)
316                 strbuf_addstr(&new_path, old_path);
317
318         free(git_man_path);
319         setenv("MANPATH", new_path.buf, 1);
320
321         strbuf_release(&new_path);
322 }
323
324 static void exec_viewer(const char *name, const char *page)
325 {
326         const char *info = get_man_viewer_info(name);
327
328         if (!strcasecmp(name, "man"))
329                 exec_man_man(info, page);
330         else if (!strcasecmp(name, "woman"))
331                 exec_woman_emacs(info, page);
332         else if (!strcasecmp(name, "konqueror"))
333                 exec_man_konqueror(info, page);
334         else if (info)
335                 exec_man_cmd(info, page);
336         else
337                 warning(_("'%s': unknown man viewer."), name);
338 }
339
340 static void show_man_page(const char *git_cmd)
341 {
342         struct man_viewer_list *viewer;
343         const char *page = cmd_to_page(git_cmd);
344         const char *fallback = getenv("GIT_MAN_VIEWER");
345
346         setup_man_path();
347         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
348         {
349                 exec_viewer(viewer->name, page); /* will return when unable */
350         }
351         if (fallback)
352                 exec_viewer(fallback, page);
353         exec_viewer("man", page);
354         die(_("no man viewer handled the request"));
355 }
356
357 static void show_info_page(const char *git_cmd)
358 {
359         const char *page = cmd_to_page(git_cmd);
360         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
361         execlp("info", "info", "gitman", page, (char *)NULL);
362         die(_("no info viewer handled the request"));
363 }
364
365 static void get_html_page_path(struct strbuf *page_path, const char *page)
366 {
367         struct stat st;
368         char *to_free = NULL;
369
370         if (!html_path)
371                 html_path = to_free = system_path(GIT_HTML_PATH);
372
373         /* Check that we have a git documentation directory. */
374         if (!strstr(html_path, "://")) {
375                 if (stat(mkpath("%s/git.html", html_path), &st)
376                     || !S_ISREG(st.st_mode))
377                         die("'%s': not a documentation directory.", html_path);
378         }
379
380         strbuf_init(page_path, 0);
381         strbuf_addf(page_path, "%s/%s.html", html_path, page);
382         free(to_free);
383 }
384
385 static void open_html(const char *path)
386 {
387         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
388 }
389
390 static void show_html_page(const char *git_cmd)
391 {
392         const char *page = cmd_to_page(git_cmd);
393         struct strbuf page_path; /* it leaks but we exec bellow */
394
395         get_html_page_path(&page_path, page);
396
397         open_html(page_path.buf);
398 }
399
400 static struct {
401         const char *name;
402         const char *help;
403 } common_guides[] = {
404         { "attributes", N_("Defining attributes per path") },
405         { "everyday", N_("Everyday Git With 20 Commands Or So") },
406         { "glossary", N_("A Git glossary") },
407         { "ignore", N_("Specifies intentionally untracked files to ignore") },
408         { "modules", N_("Defining submodule properties") },
409         { "revisions", N_("Specifying revisions and ranges for Git") },
410         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
411         { "workflows", N_("An overview of recommended workflows with Git") },
412 };
413
414 static void list_common_guides_help(void)
415 {
416         int i, longest = 0;
417
418         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
419                 if (longest < strlen(common_guides[i].name))
420                         longest = strlen(common_guides[i].name);
421         }
422
423         puts(_("The common Git guides are:\n"));
424         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
425                 printf("   %s   ", common_guides[i].name);
426                 mput_char(' ', longest - strlen(common_guides[i].name));
427                 puts(_(common_guides[i].help));
428         }
429         putchar('\n');
430 }
431
432 static const char *check_git_cmd(const char* cmd)
433 {
434         char *alias;
435
436         if (is_git_command(cmd))
437                 return cmd;
438
439         alias = alias_lookup(cmd);
440         if (alias) {
441                 printf_ln(_("`git %s' is aliased to `%s'"), cmd, alias);
442                 free(alias);
443                 exit(0);
444         }
445
446         if (exclude_guides)
447                 return help_unknown_cmd(cmd);
448
449         return cmd;
450 }
451
452 int cmd_help(int argc, const char **argv, const char *prefix)
453 {
454         int nongit;
455         enum help_format parsed_help_format;
456
457         argc = parse_options(argc, argv, prefix, builtin_help_options,
458                         builtin_help_usage, 0);
459         parsed_help_format = help_format;
460
461         if (show_all) {
462                 git_config(git_help_config, NULL);
463                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
464                 load_command_list("git-", &main_cmds, &other_cmds);
465                 list_commands(colopts, &main_cmds, &other_cmds);
466         }
467
468         if (show_guides)
469                 list_common_guides_help();
470
471         if (show_all || show_guides) {
472                 printf("%s\n", _(git_more_info_string));
473                 /*
474                 * We're done. Ignore any remaining args
475                 */
476                 return 0;
477         }
478
479         if (!argv[0]) {
480                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
481                 list_common_cmds_help();
482                 printf("\n%s\n", _(git_more_info_string));
483                 return 0;
484         }
485
486         setup_git_directory_gently(&nongit);
487         git_config(git_help_config, NULL);
488
489         if (parsed_help_format != HELP_FORMAT_NONE)
490                 help_format = parsed_help_format;
491         if (help_format == HELP_FORMAT_NONE)
492                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
493
494         argv[0] = check_git_cmd(argv[0]);
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 }