diff: do not use null sha1 as a sentinel value
[git/git.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_NONE,
27 HELP_FORMAT_MAN,
28 HELP_FORMAT_INFO,
29 HELP_FORMAT_WEB
30 };
31
32 static int show_all = 0;
33 static enum help_format help_format = HELP_FORMAT_NONE;
34 static struct option builtin_help_options[] = {
35 OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
36 OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
37 OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
38 HELP_FORMAT_WEB),
39 OPT_SET_INT('i', "info", &help_format, "show info page",
40 HELP_FORMAT_INFO),
41 OPT_END(),
42 };
43
44 static const char * const builtin_help_usage[] = {
45 "git help [--all] [--man|--web|--info] [command]",
46 NULL
47 };
48
49 static enum help_format parse_help_format(const char *format)
50 {
51 if (!strcmp(format, "man"))
52 return HELP_FORMAT_MAN;
53 if (!strcmp(format, "info"))
54 return HELP_FORMAT_INFO;
55 if (!strcmp(format, "web") || !strcmp(format, "html"))
56 return HELP_FORMAT_WEB;
57 die("unrecognized help format '%s'", format);
58 }
59
60 static const char *get_man_viewer_info(const char *name)
61 {
62 struct man_viewer_info_list *viewer;
63
64 for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
65 {
66 if (!strcasecmp(name, viewer->name))
67 return viewer->info;
68 }
69 return NULL;
70 }
71
72 static int check_emacsclient_version(void)
73 {
74 struct strbuf buffer = STRBUF_INIT;
75 struct child_process ec_process;
76 const char *argv_ec[] = { "emacsclient", "--version", NULL };
77 int version;
78
79 /* emacsclient prints its version number on stderr */
80 memset(&ec_process, 0, sizeof(ec_process));
81 ec_process.argv = argv_ec;
82 ec_process.err = -1;
83 ec_process.stdout_to_stderr = 1;
84 if (start_command(&ec_process))
85 return error("Failed to start emacsclient.");
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 strbuf_release(&buffer);
98 return error("Failed to parse emacsclient version.");
99 }
100
101 strbuf_remove(&buffer, 0, strlen("emacsclient"));
102 version = atoi(buffer.buf);
103
104 if (version < 22) {
105 strbuf_release(&buffer);
106 return error("emacsclient version '%d' too old (< 22).",
107 version);
108 }
109
110 strbuf_release(&buffer);
111 return 0;
112 }
113
114 static void exec_woman_emacs(const char *path, const char *page)
115 {
116 if (!check_emacsclient_version()) {
117 /* This works only with emacsclient version >= 22. */
118 struct strbuf man_page = STRBUF_INIT;
119
120 if (!path)
121 path = "emacsclient";
122 strbuf_addf(&man_page, "(woman \"%s\")", page);
123 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
124 warning("failed to exec '%s': %s", path, strerror(errno));
125 }
126 }
127
128 static void exec_man_konqueror(const char *path, const char *page)
129 {
130 const char *display = getenv("DISPLAY");
131 if (display && *display) {
132 struct strbuf man_page = STRBUF_INIT;
133 const char *filename = "kfmclient";
134
135 /* It's simpler to launch konqueror using kfmclient. */
136 if (path) {
137 const char *file = strrchr(path, '/');
138 if (file && !strcmp(file + 1, "konqueror")) {
139 char *new = xstrdup(path);
140 char *dest = strrchr(new, '/');
141
142 /* strlen("konqueror") == strlen("kfmclient") */
143 strcpy(dest + 1, "kfmclient");
144 path = new;
145 }
146 if (file)
147 filename = file;
148 } else
149 path = "kfmclient";
150 strbuf_addf(&man_page, "man:%s(1)", page);
151 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
152 warning("failed to exec '%s': %s", path, strerror(errno));
153 }
154 }
155
156 static void exec_man_man(const char *path, const char *page)
157 {
158 if (!path)
159 path = "man";
160 execlp(path, "man", page, (char *)NULL);
161 warning("failed to exec '%s': %s", path, strerror(errno));
162 }
163
164 static void exec_man_cmd(const char *cmd, const char *page)
165 {
166 struct strbuf shell_cmd = STRBUF_INIT;
167 strbuf_addf(&shell_cmd, "%s %s", cmd, page);
168 execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
169 warning("failed to exec '%s': %s", cmd, strerror(errno));
170 }
171
172 static void add_man_viewer(const char *name)
173 {
174 struct man_viewer_list **p = &man_viewer_list;
175 size_t len = strlen(name);
176
177 while (*p)
178 p = &((*p)->next);
179 *p = xcalloc(1, (sizeof(**p) + len + 1));
180 strncpy((*p)->name, name, len);
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 = xcalloc(1, sizeof(*new) + len + 1);
195
196 strncpy(new->name, name, len);
197 new->info = xstrdup(value);
198 new->next = man_viewer_info_list;
199 man_viewer_info_list = new;
200 }
201
202 static int add_man_viewer_path(const char *name,
203 size_t len,
204 const char *value)
205 {
206 if (supported_man_viewer(name, len))
207 do_add_man_viewer_info(name, len, value);
208 else
209 warning("'%s': path for unsupported man viewer.\n"
210 "Please consider using 'man.<tool>.cmd' instead.",
211 name);
212
213 return 0;
214 }
215
216 static int add_man_viewer_cmd(const char *name,
217 size_t len,
218 const char *value)
219 {
220 if (supported_man_viewer(name, len))
221 warning("'%s': cmd for supported man viewer.\n"
222 "Please consider using 'man.<tool>.path' instead.",
223 name);
224 else
225 do_add_man_viewer_info(name, len, value);
226
227 return 0;
228 }
229
230 static int add_man_viewer_info(const char *var, const char *value)
231 {
232 const char *name = var + 4;
233 const char *subkey = strrchr(name, '.');
234
235 if (!subkey)
236 return 0;
237
238 if (!strcmp(subkey, ".path")) {
239 if (!value)
240 return config_error_nonbool(var);
241 return add_man_viewer_path(name, subkey - name, value);
242 }
243 if (!strcmp(subkey, ".cmd")) {
244 if (!value)
245 return config_error_nonbool(var);
246 return add_man_viewer_cmd(name, subkey - name, value);
247 }
248
249 return 0;
250 }
251
252 static int git_help_config(const char *var, const char *value, void *cb)
253 {
254 if (!strcmp(var, "help.format")) {
255 if (!value)
256 return config_error_nonbool(var);
257 help_format = parse_help_format(value);
258 return 0;
259 }
260 if (!strcmp(var, "man.viewer")) {
261 if (!value)
262 return config_error_nonbool(var);
263 add_man_viewer(value);
264 return 0;
265 }
266 if (!prefixcmp(var, "man."))
267 return add_man_viewer_info(var, value);
268
269 return git_default_config(var, value, cb);
270 }
271
272 static struct cmdnames main_cmds, other_cmds;
273
274 void list_common_cmds_help(void)
275 {
276 int i, longest = 0;
277
278 for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
279 if (longest < strlen(common_cmds[i].name))
280 longest = strlen(common_cmds[i].name);
281 }
282
283 puts("The most commonly used git commands are:");
284 for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
285 printf(" %s ", common_cmds[i].name);
286 mput_char(' ', longest - strlen(common_cmds[i].name));
287 puts(common_cmds[i].help);
288 }
289 }
290
291 static int is_git_command(const char *s)
292 {
293 return is_in_cmdlist(&main_cmds, s) ||
294 is_in_cmdlist(&other_cmds, s);
295 }
296
297 static const char *prepend(const char *prefix, const char *cmd)
298 {
299 size_t pre_len = strlen(prefix);
300 size_t cmd_len = strlen(cmd);
301 char *p = xmalloc(pre_len + cmd_len + 1);
302 memcpy(p, prefix, pre_len);
303 strcpy(p + pre_len, cmd);
304 return p;
305 }
306
307 static const char *cmd_to_page(const char *git_cmd)
308 {
309 if (!git_cmd)
310 return "git";
311 else if (!prefixcmp(git_cmd, "git"))
312 return git_cmd;
313 else if (is_git_command(git_cmd))
314 return prepend("git-", git_cmd);
315 else
316 return prepend("git", git_cmd);
317 }
318
319 static void setup_man_path(void)
320 {
321 struct strbuf new_path = STRBUF_INIT;
322 const char *old_path = getenv("MANPATH");
323
324 /* We should always put ':' after our path. If there is no
325 * old_path, the ':' at the end will let 'man' to try
326 * system-wide paths after ours to find the manual page. If
327 * there is old_path, we need ':' as delimiter. */
328 strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
329 strbuf_addch(&new_path, ':');
330 if (old_path)
331 strbuf_addstr(&new_path, old_path);
332
333 setenv("MANPATH", new_path.buf, 1);
334
335 strbuf_release(&new_path);
336 }
337
338 static void exec_viewer(const char *name, const char *page)
339 {
340 const char *info = get_man_viewer_info(name);
341
342 if (!strcasecmp(name, "man"))
343 exec_man_man(info, page);
344 else if (!strcasecmp(name, "woman"))
345 exec_woman_emacs(info, page);
346 else if (!strcasecmp(name, "konqueror"))
347 exec_man_konqueror(info, page);
348 else if (info)
349 exec_man_cmd(info, page);
350 else
351 warning("'%s': unknown man viewer.", name);
352 }
353
354 static void show_man_page(const char *git_cmd)
355 {
356 struct man_viewer_list *viewer;
357 const char *page = cmd_to_page(git_cmd);
358 const char *fallback = getenv("GIT_MAN_VIEWER");
359
360 setup_man_path();
361 for (viewer = man_viewer_list; viewer; viewer = viewer->next)
362 {
363 exec_viewer(viewer->name, page); /* will return when unable */
364 }
365 if (fallback)
366 exec_viewer(fallback, page);
367 exec_viewer("man", page);
368 die("no man viewer handled the request");
369 }
370
371 static void show_info_page(const char *git_cmd)
372 {
373 const char *page = cmd_to_page(git_cmd);
374 setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
375 execlp("info", "info", "gitman", page, (char *)NULL);
376 die("no info viewer handled the request");
377 }
378
379 static void get_html_page_path(struct strbuf *page_path, const char *page)
380 {
381 struct stat st;
382 const char *html_path = system_path(GIT_HTML_PATH);
383
384 /* Check that we have a git documentation directory. */
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 strbuf_init(page_path, 0);
390 strbuf_addf(page_path, "%s/%s.html", html_path, page);
391 }
392
393 /*
394 * If open_html is not defined in a platform-specific way (see for
395 * example compat/mingw.h), we use the script web--browse to display
396 * HTML.
397 */
398 #ifndef open_html
399 static void open_html(const char *path)
400 {
401 execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
402 }
403 #endif
404
405 static void show_html_page(const char *git_cmd)
406 {
407 const char *page = cmd_to_page(git_cmd);
408 struct strbuf page_path; /* it leaks but we exec bellow */
409
410 get_html_page_path(&page_path, page);
411
412 open_html(page_path.buf);
413 }
414
415 int cmd_help(int argc, const char **argv, const char *prefix)
416 {
417 int nongit;
418 const char *alias;
419 enum help_format parsed_help_format;
420 load_command_list("git-", &main_cmds, &other_cmds);
421
422 argc = parse_options(argc, argv, prefix, builtin_help_options,
423 builtin_help_usage, 0);
424 parsed_help_format = help_format;
425
426 if (show_all) {
427 printf("usage: %s\n\n", git_usage_string);
428 list_commands("git commands", &main_cmds, &other_cmds);
429 printf("%s\n", git_more_info_string);
430 return 0;
431 }
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 setup_git_directory_gently(&nongit);
441 git_config(git_help_config, NULL);
442
443 if (parsed_help_format != HELP_FORMAT_NONE)
444 help_format = parsed_help_format;
445
446 alias = alias_lookup(argv[0]);
447 if (alias && !is_git_command(argv[0])) {
448 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
449 return 0;
450 }
451
452 switch (help_format) {
453 case HELP_FORMAT_NONE:
454 case HELP_FORMAT_MAN:
455 show_man_page(argv[0]);
456 break;
457 case HELP_FORMAT_INFO:
458 show_info_page(argv[0]);
459 break;
460 case HELP_FORMAT_WEB:
461 show_html_page(argv[0]);
462 break;
463 }
464
465 return 0;
466 }