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 }