Merge branch 'mm/maint-merge-ff-error-message-fix'
[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 "help.h"
13
14 static struct man_viewer_list {
15         struct man_viewer_list *next;
16         char name[FLEX_ARRAY];
17 } *man_viewer_list;
18
19 static struct man_viewer_info_list {
20         struct man_viewer_info_list *next;
21         const char *info;
22         char name[FLEX_ARRAY];
23 } *man_viewer_info_list;
24
25 enum help_format {
26         HELP_FORMAT_MAN,
27         HELP_FORMAT_INFO,
28         HELP_FORMAT_WEB,
29 };
30
31 static int show_all = 0;
32 static enum help_format help_format = HELP_FORMAT_MAN;
33 static struct option builtin_help_options[] = {
34         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
35         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
36         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
37                         HELP_FORMAT_WEB),
38         OPT_SET_INT('i', "info", &help_format, "show info page",
39                         HELP_FORMAT_INFO),
40         OPT_END(),
41 };
42
43 static const char * const builtin_help_usage[] = {
44         "git help [--all] [--man|--web|--info] [command]",
45         NULL
46 };
47
48 static enum help_format parse_help_format(const char *format)
49 {
50         if (!strcmp(format, "man"))
51                 return HELP_FORMAT_MAN;
52         if (!strcmp(format, "info"))
53                 return HELP_FORMAT_INFO;
54         if (!strcmp(format, "web") || !strcmp(format, "html"))
55                 return HELP_FORMAT_WEB;
56         die("unrecognized help format '%s'", format);
57 }
58
59 static const char *get_man_viewer_info(const char *name)
60 {
61         struct man_viewer_info_list *viewer;
62
63         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
64         {
65                 if (!strcasecmp(name, viewer->name))
66                         return viewer->info;
67         }
68         return NULL;
69 }
70
71 static int check_emacsclient_version(void)
72 {
73         struct strbuf buffer = STRBUF_INIT;
74         struct child_process ec_process;
75         const char *argv_ec[] = { "emacsclient", "--version", NULL };
76         int version;
77
78         /* emacsclient prints its version number on stderr */
79         memset(&ec_process, 0, sizeof(ec_process));
80         ec_process.argv = argv_ec;
81         ec_process.err = -1;
82         ec_process.stdout_to_stderr = 1;
83         if (start_command(&ec_process))
84                 return error("Failed to start emacsclient.");
85
86         strbuf_read(&buffer, ec_process.err, 20);
87         close(ec_process.err);
88
89         /*
90          * Don't bother checking return value, because "emacsclient --version"
91          * seems to always exits with code 1.
92          */
93         finish_command(&ec_process);
94
95         if (prefixcmp(buffer.buf, "emacsclient")) {
96                 strbuf_release(&buffer);
97                 return error("Failed to parse emacsclient version.");
98         }
99
100         strbuf_remove(&buffer, 0, strlen("emacsclient"));
101         version = atoi(buffer.buf);
102
103         if (version < 22) {
104                 strbuf_release(&buffer);
105                 return error("emacsclient version '%d' too old (< 22).",
106                         version);
107         }
108
109         strbuf_release(&buffer);
110         return 0;
111 }
112
113 static void exec_woman_emacs(const char *path, const char *page)
114 {
115         if (!check_emacsclient_version()) {
116                 /* This works only with emacsclient version >= 22. */
117                 struct strbuf man_page = STRBUF_INIT;
118
119                 if (!path)
120                         path = "emacsclient";
121                 strbuf_addf(&man_page, "(woman \"%s\")", page);
122                 execlp(path, "emacsclient", "-e", man_page.buf, NULL);
123                 warning("failed to exec '%s': %s", path, strerror(errno));
124         }
125 }
126
127 static void exec_man_konqueror(const char *path, const char *page)
128 {
129         const char *display = getenv("DISPLAY");
130         if (display && *display) {
131                 struct strbuf man_page = STRBUF_INIT;
132                 const char *filename = "kfmclient";
133
134                 /* It's simpler to launch konqueror using kfmclient. */
135                 if (path) {
136                         const char *file = strrchr(path, '/');
137                         if (file && !strcmp(file + 1, "konqueror")) {
138                                 char *new = xstrdup(path);
139                                 char *dest = strrchr(new, '/');
140
141                                 /* strlen("konqueror") == strlen("kfmclient") */
142                                 strcpy(dest + 1, "kfmclient");
143                                 path = new;
144                         }
145                         if (file)
146                                 filename = file;
147                 } else
148                         path = "kfmclient";
149                 strbuf_addf(&man_page, "man:%s(1)", page);
150                 execlp(path, filename, "newTab", man_page.buf, NULL);
151                 warning("failed to exec '%s': %s", path, strerror(errno));
152         }
153 }
154
155 static void exec_man_man(const char *path, const char *page)
156 {
157         if (!path)
158                 path = "man";
159         execlp(path, "man", page, NULL);
160         warning("failed to exec '%s': %s", path, strerror(errno));
161 }
162
163 static void exec_man_cmd(const char *cmd, const char *page)
164 {
165         struct strbuf shell_cmd = STRBUF_INIT;
166         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
167         execl("/bin/sh", "sh", "-c", shell_cmd.buf, NULL);
168         warning("failed to exec '%s': %s", cmd, strerror(errno));
169 }
170
171 static void add_man_viewer(const char *name)
172 {
173         struct man_viewer_list **p = &man_viewer_list;
174         size_t len = strlen(name);
175
176         while (*p)
177                 p = &((*p)->next);
178         *p = xcalloc(1, (sizeof(**p) + len + 1));
179         strncpy((*p)->name, name, len);
180 }
181
182 static int supported_man_viewer(const char *name, size_t len)
183 {
184         return (!strncasecmp("man", name, len) ||
185                 !strncasecmp("woman", name, len) ||
186                 !strncasecmp("konqueror", name, len));
187 }
188
189 static void do_add_man_viewer_info(const char *name,
190                                    size_t len,
191                                    const char *value)
192 {
193         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
194
195         strncpy(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 = var + 4;
232         const char *subkey = strrchr(name, '.');
233
234         if (!subkey)
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, subkey - name, value);
241         }
242         if (!strcmp(subkey, ".cmd")) {
243                 if (!value)
244                         return config_error_nonbool(var);
245                 return add_man_viewer_cmd(name, subkey - name, 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 (!strcmp(var, "help.format")) {
254                 if (!value)
255                         return config_error_nonbool(var);
256                 help_format = parse_help_format(value);
257                 return 0;
258         }
259         if (!strcmp(var, "man.viewer")) {
260                 if (!value)
261                         return config_error_nonbool(var);
262                 add_man_viewer(value);
263                 return 0;
264         }
265         if (!prefixcmp(var, "man."))
266                 return add_man_viewer_info(var, value);
267
268         return git_default_config(var, value, cb);
269 }
270
271 static struct cmdnames main_cmds, other_cmds;
272
273 void list_common_cmds_help(void)
274 {
275         int i, longest = 0;
276
277         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
278                 if (longest < strlen(common_cmds[i].name))
279                         longest = strlen(common_cmds[i].name);
280         }
281
282         puts("The most commonly used git commands are:");
283         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
284                 printf("   %s   ", common_cmds[i].name);
285                 mput_char(' ', longest - strlen(common_cmds[i].name));
286                 puts(common_cmds[i].help);
287         }
288 }
289
290 static int is_git_command(const char *s)
291 {
292         return is_in_cmdlist(&main_cmds, s) ||
293                 is_in_cmdlist(&other_cmds, s);
294 }
295
296 static const char *prepend(const char *prefix, const char *cmd)
297 {
298         size_t pre_len = strlen(prefix);
299         size_t cmd_len = strlen(cmd);
300         char *p = xmalloc(pre_len + cmd_len + 1);
301         memcpy(p, prefix, pre_len);
302         strcpy(p + pre_len, cmd);
303         return p;
304 }
305
306 static const char *cmd_to_page(const char *git_cmd)
307 {
308         if (!git_cmd)
309                 return "git";
310         else if (!prefixcmp(git_cmd, "git"))
311                 return git_cmd;
312         else if (is_git_command(git_cmd))
313                 return prepend("git-", git_cmd);
314         else
315                 return prepend("git", git_cmd);
316 }
317
318 static void setup_man_path(void)
319 {
320         struct strbuf new_path = STRBUF_INIT;
321         const char *old_path = getenv("MANPATH");
322
323         /* We should always put ':' after our path. If there is no
324          * old_path, the ':' at the end will let 'man' to try
325          * system-wide paths after ours to find the manual page. If
326          * there is old_path, we need ':' as delimiter. */
327         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
328         strbuf_addch(&new_path, ':');
329         if (old_path)
330                 strbuf_addstr(&new_path, old_path);
331
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, 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         const char *html_path = system_path(GIT_HTML_PATH);
382
383         /* Check that we have a git documentation directory. */
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         strbuf_init(page_path, 0);
389         strbuf_addf(page_path, "%s/%s.html", html_path, page);
390 }
391
392 /*
393  * If open_html is not defined in a platform-specific way (see for
394  * example compat/mingw.h), we use the script web--browse to display
395  * HTML.
396  */
397 #ifndef open_html
398 static void open_html(const char *path)
399 {
400         execl_git_cmd("web--browse", "-c", "help.browser", path, NULL);
401 }
402 #endif
403
404 static void show_html_page(const char *git_cmd)
405 {
406         const char *page = cmd_to_page(git_cmd);
407         struct strbuf page_path; /* it leaks but we exec bellow */
408
409         get_html_page_path(&page_path, page);
410
411         open_html(page_path.buf);
412 }
413
414 int cmd_help(int argc, const char **argv, const char *prefix)
415 {
416         int nongit;
417         const char *alias;
418         load_command_list("git-", &main_cmds, &other_cmds);
419
420         argc = parse_options(argc, argv, prefix, builtin_help_options,
421                         builtin_help_usage, 0);
422
423         if (show_all) {
424                 printf("usage: %s\n\n", git_usage_string);
425                 list_commands("git commands", &main_cmds, &other_cmds);
426                 printf("%s\n", git_more_info_string);
427                 return 0;
428         }
429
430         setup_git_directory_gently(&nongit);
431         git_config(git_help_config, NULL);
432
433         if (!argv[0]) {
434                 printf("usage: %s\n\n", git_usage_string);
435                 list_common_cmds_help();
436                 printf("\n%s\n", git_more_info_string);
437                 return 0;
438         }
439
440         alias = alias_lookup(argv[0]);
441         if (alias && !is_git_command(argv[0])) {
442                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
443                 return 0;
444         }
445
446         switch (help_format) {
447         case HELP_FORMAT_MAN:
448                 show_man_page(argv[0]);
449                 break;
450         case HELP_FORMAT_INFO:
451                 show_info_page(argv[0]);
452                 break;
453         case HELP_FORMAT_WEB:
454                 show_html_page(argv[0]);
455                 break;
456         }
457
458         return 0;
459 }