completion: complete values for log.date
[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                 fprintf(stderr, "Failed to start emacsclient.\n");
85                 return -1;
86         }
87         strbuf_read(&buffer, ec_process.err, 20);
88         close(ec_process.err);
89
90         /*
91          * Don't bother checking return value, because "emacsclient --version"
92          * seems to always exits with code 1.
93          */
94         finish_command(&ec_process);
95
96         if (prefixcmp(buffer.buf, "emacsclient")) {
97                 fprintf(stderr, "Failed to parse emacsclient version.\n");
98                 strbuf_release(&buffer);
99                 return -1;
100         }
101
102         strbuf_remove(&buffer, 0, strlen("emacsclient"));
103         version = atoi(buffer.buf);
104
105         if (version < 22) {
106                 fprintf(stderr,
107                         "emacsclient version '%d' too old (< 22).\n",
108                         version);
109                 strbuf_release(&buffer);
110                 return -1;
111         }
112
113         strbuf_release(&buffer);
114         return 0;
115 }
116
117 static void exec_woman_emacs(const char *path, const char *page)
118 {
119         if (!check_emacsclient_version()) {
120                 /* This works only with emacsclient version >= 22. */
121                 struct strbuf man_page = STRBUF_INIT;
122
123                 if (!path)
124                         path = "emacsclient";
125                 strbuf_addf(&man_page, "(woman \"%s\")", page);
126                 execlp(path, "emacsclient", "-e", man_page.buf, NULL);
127                 warning("failed to exec '%s': %s", path, strerror(errno));
128         }
129 }
130
131 static void exec_man_konqueror(const char *path, const char *page)
132 {
133         const char *display = getenv("DISPLAY");
134         if (display && *display) {
135                 struct strbuf man_page = STRBUF_INIT;
136                 const char *filename = "kfmclient";
137
138                 /* It's simpler to launch konqueror using kfmclient. */
139                 if (path) {
140                         const char *file = strrchr(path, '/');
141                         if (file && !strcmp(file + 1, "konqueror")) {
142                                 char *new = xstrdup(path);
143                                 char *dest = strrchr(new, '/');
144
145                                 /* strlen("konqueror") == strlen("kfmclient") */
146                                 strcpy(dest + 1, "kfmclient");
147                                 path = new;
148                         }
149                         if (file)
150                                 filename = file;
151                 } else
152                         path = "kfmclient";
153                 strbuf_addf(&man_page, "man:%s(1)", page);
154                 execlp(path, filename, "newTab", man_page.buf, NULL);
155                 warning("failed to exec '%s': %s", path, strerror(errno));
156         }
157 }
158
159 static void exec_man_man(const char *path, const char *page)
160 {
161         if (!path)
162                 path = "man";
163         execlp(path, "man", page, NULL);
164         warning("failed to exec '%s': %s", path, strerror(errno));
165 }
166
167 static void exec_man_cmd(const char *cmd, const char *page)
168 {
169         struct strbuf shell_cmd = STRBUF_INIT;
170         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
171         execl("/bin/sh", "sh", "-c", shell_cmd.buf, NULL);
172         warning("failed to exec '%s': %s", cmd, strerror(errno));
173 }
174
175 static void add_man_viewer(const char *name)
176 {
177         struct man_viewer_list **p = &man_viewer_list;
178         size_t len = strlen(name);
179
180         while (*p)
181                 p = &((*p)->next);
182         *p = xcalloc(1, (sizeof(**p) + len + 1));
183         strncpy((*p)->name, name, len);
184 }
185
186 static int supported_man_viewer(const char *name, size_t len)
187 {
188         return (!strncasecmp("man", name, len) ||
189                 !strncasecmp("woman", name, len) ||
190                 !strncasecmp("konqueror", name, len));
191 }
192
193 static void do_add_man_viewer_info(const char *name,
194                                    size_t len,
195                                    const char *value)
196 {
197         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
198
199         strncpy(new->name, name, len);
200         new->info = xstrdup(value);
201         new->next = man_viewer_info_list;
202         man_viewer_info_list = new;
203 }
204
205 static int add_man_viewer_path(const char *name,
206                                size_t len,
207                                const char *value)
208 {
209         if (supported_man_viewer(name, len))
210                 do_add_man_viewer_info(name, len, value);
211         else
212                 warning("'%s': path for unsupported man viewer.\n"
213                         "Please consider using 'man.<tool>.cmd' instead.",
214                         name);
215
216         return 0;
217 }
218
219 static int add_man_viewer_cmd(const char *name,
220                               size_t len,
221                               const char *value)
222 {
223         if (supported_man_viewer(name, len))
224                 warning("'%s': cmd for supported man viewer.\n"
225                         "Please consider using 'man.<tool>.path' instead.",
226                         name);
227         else
228                 do_add_man_viewer_info(name, len, value);
229
230         return 0;
231 }
232
233 static int add_man_viewer_info(const char *var, const char *value)
234 {
235         const char *name = var + 4;
236         const char *subkey = strrchr(name, '.');
237
238         if (!subkey)
239                 return 0;
240
241         if (!strcmp(subkey, ".path")) {
242                 if (!value)
243                         return config_error_nonbool(var);
244                 return add_man_viewer_path(name, subkey - name, value);
245         }
246         if (!strcmp(subkey, ".cmd")) {
247                 if (!value)
248                         return config_error_nonbool(var);
249                 return add_man_viewer_cmd(name, subkey - name, value);
250         }
251
252         return 0;
253 }
254
255 static int git_help_config(const char *var, const char *value, void *cb)
256 {
257         if (!strcmp(var, "help.format")) {
258                 if (!value)
259                         return config_error_nonbool(var);
260                 help_format = parse_help_format(value);
261                 return 0;
262         }
263         if (!strcmp(var, "man.viewer")) {
264                 if (!value)
265                         return config_error_nonbool(var);
266                 add_man_viewer(value);
267                 return 0;
268         }
269         if (!prefixcmp(var, "man."))
270                 return add_man_viewer_info(var, value);
271
272         return git_default_config(var, value, cb);
273 }
274
275 static struct cmdnames main_cmds, other_cmds;
276
277 void list_common_cmds_help(void)
278 {
279         int i, longest = 0;
280
281         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
282                 if (longest < strlen(common_cmds[i].name))
283                         longest = strlen(common_cmds[i].name);
284         }
285
286         puts("The most commonly used git commands are:");
287         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
288                 printf("   %s   ", common_cmds[i].name);
289                 mput_char(' ', longest - strlen(common_cmds[i].name));
290                 puts(common_cmds[i].help);
291         }
292 }
293
294 static int is_git_command(const char *s)
295 {
296         return is_in_cmdlist(&main_cmds, s) ||
297                 is_in_cmdlist(&other_cmds, s);
298 }
299
300 static const char *prepend(const char *prefix, const char *cmd)
301 {
302         size_t pre_len = strlen(prefix);
303         size_t cmd_len = strlen(cmd);
304         char *p = xmalloc(pre_len + cmd_len + 1);
305         memcpy(p, prefix, pre_len);
306         strcpy(p + pre_len, cmd);
307         return p;
308 }
309
310 static const char *cmd_to_page(const char *git_cmd)
311 {
312         if (!git_cmd)
313                 return "git";
314         else if (!prefixcmp(git_cmd, "git"))
315                 return git_cmd;
316         else if (is_git_command(git_cmd))
317                 return prepend("git-", git_cmd);
318         else
319                 return prepend("git", git_cmd);
320 }
321
322 static void setup_man_path(void)
323 {
324         struct strbuf new_path = STRBUF_INIT;
325         const char *old_path = getenv("MANPATH");
326
327         /* We should always put ':' after our path. If there is no
328          * old_path, the ':' at the end will let 'man' to try
329          * system-wide paths after ours to find the manual page. If
330          * there is old_path, we need ':' as delimiter. */
331         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
332         strbuf_addch(&new_path, ':');
333         if (old_path)
334                 strbuf_addstr(&new_path, old_path);
335
336         setenv("MANPATH", new_path.buf, 1);
337
338         strbuf_release(&new_path);
339 }
340
341 static void exec_viewer(const char *name, const char *page)
342 {
343         const char *info = get_man_viewer_info(name);
344
345         if (!strcasecmp(name, "man"))
346                 exec_man_man(info, page);
347         else if (!strcasecmp(name, "woman"))
348                 exec_woman_emacs(info, page);
349         else if (!strcasecmp(name, "konqueror"))
350                 exec_man_konqueror(info, page);
351         else if (info)
352                 exec_man_cmd(info, page);
353         else
354                 warning("'%s': unknown man viewer.", name);
355 }
356
357 static void show_man_page(const char *git_cmd)
358 {
359         struct man_viewer_list *viewer;
360         const char *page = cmd_to_page(git_cmd);
361         const char *fallback = getenv("GIT_MAN_VIEWER");
362
363         setup_man_path();
364         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
365         {
366                 exec_viewer(viewer->name, page); /* will return when unable */
367         }
368         if (fallback)
369                 exec_viewer(fallback, page);
370         exec_viewer("man", page);
371         die("no man viewer handled the request");
372 }
373
374 static void show_info_page(const char *git_cmd)
375 {
376         const char *page = cmd_to_page(git_cmd);
377         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
378         execlp("info", "info", "gitman", page, NULL);
379 }
380
381 static void get_html_page_path(struct strbuf *page_path, const char *page)
382 {
383         struct stat st;
384         const char *html_path = system_path(GIT_HTML_PATH);
385
386         /* Check that we have a git documentation directory. */
387         if (stat(mkpath("%s/git.html", html_path), &st)
388             || !S_ISREG(st.st_mode))
389                 die("'%s': not a documentation directory.", html_path);
390
391         strbuf_init(page_path, 0);
392         strbuf_addf(page_path, "%s/%s.html", html_path, page);
393 }
394
395 /*
396  * If open_html is not defined in a platform-specific way (see for
397  * example compat/mingw.h), we use the script web--browse to display
398  * HTML.
399  */
400 #ifndef open_html
401 void open_html(const char *path)
402 {
403         execl_git_cmd("web--browse", "-c", "help.browser", path, NULL);
404 }
405 #endif
406
407 static void show_html_page(const char *git_cmd)
408 {
409         const char *page = cmd_to_page(git_cmd);
410         struct strbuf page_path; /* it leaks but we exec bellow */
411
412         get_html_page_path(&page_path, page);
413
414         open_html(page_path.buf);
415 }
416
417 int cmd_help(int argc, const char **argv, const char *prefix)
418 {
419         int nongit;
420         const char *alias;
421         load_command_list("git-", &main_cmds, &other_cmds);
422
423         setup_git_directory_gently(&nongit);
424         git_config(git_help_config, NULL);
425
426         argc = parse_options(argc, argv, builtin_help_options,
427                         builtin_help_usage, 0);
428
429         if (show_all) {
430                 printf("usage: %s\n\n", git_usage_string);
431                 list_commands("git commands", &main_cmds, &other_cmds);
432                 printf("%s\n", git_more_info_string);
433                 return 0;
434         }
435
436         if (!argv[0]) {
437                 printf("usage: %s\n\n", git_usage_string);
438                 list_common_cmds_help();
439                 printf("\n%s\n", git_more_info_string);
440                 return 0;
441         }
442
443         alias = alias_lookup(argv[0]);
444         if (alias && !is_git_command(argv[0])) {
445                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
446                 return 0;
447         }
448
449         switch (help_format) {
450         case HELP_FORMAT_MAN:
451                 show_man_page(argv[0]);
452                 break;
453         case HELP_FORMAT_INFO:
454                 show_info_page(argv[0]);
455                 break;
456         case HELP_FORMAT_WEB:
457                 show_html_page(argv[0]);
458                 break;
459         }
460
461         return 0;
462 }