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 "config-list.h"
  12 #include "help.h"
  13 #include "alias.h"
  14
  15 #ifndef DEFAULT_HELP_FORMAT
  16 #define DEFAULT_HELP_FORMAT "man"
  17 #endif
  18
  19 static struct man_viewer_list {
  20         struct man_viewer_list *next;
  21         char name[FLEX_ARRAY];
  22 } *man_viewer_list;
  23
  24 static struct man_viewer_info_list {
  25         struct man_viewer_info_list *next;
  26         const char *info;
  27         char name[FLEX_ARRAY];
  28 } *man_viewer_info_list;
  29
  30 enum help_format {
  31         HELP_FORMAT_NONE,
  32         HELP_FORMAT_MAN,
  33         HELP_FORMAT_INFO,
  34         HELP_FORMAT_WEB
  35 };
  36
  37 static const char *html_path;
  38
  39 static int show_all = 0;
  40 static int show_guides = 0;
  41 static int show_config;
  42 static int verbose = 1;
  43 static unsigned int colopts;
  44 static enum help_format help_format = HELP_FORMAT_NONE;
  45 static int exclude_guides;
  46 static struct option builtin_help_options[] = {
  47         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
  48         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
  49         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
  50         OPT_BOOL('c', "config", &show_config, N_("print all configuration variable names")),
  51         OPT_SET_INT_F(0, "config-for-completion", &show_config, "", 2, PARSE_OPT_HIDDEN),
  52         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  53         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  54                         HELP_FORMAT_WEB),
  55         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  56                         HELP_FORMAT_INFO),
  57         OPT__VERBOSE(&verbose, N_("print command description")),
  58         OPT_END(),
  59 };
  60
  61 static const char * const builtin_help_usage[] = {
  62         N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
  63         NULL
  64 };
  65
  66 struct slot_expansion {
  67         const char *prefix;
  68         const char *placeholder;
  69         void (*fn)(struct string_list *list, const char *prefix);
  70         int found;
  71 };
  72
  73 static void list_config_help(int for_human)
  74 {
  75         struct slot_expansion slot_expansions[] = {
  76                 { "advice", "*", list_config_advices },
  77                 { "color.branch", "<slot>", list_config_color_branch_slots },
  78                 { "color.decorate", "<slot>", list_config_color_decorate_slots },
  79                 { "color.diff", "<slot>", list_config_color_diff_slots },
  80                 { "color.grep", "<slot>", list_config_color_grep_slots },
  81                 { "color.interactive", "<slot>", list_config_color_interactive_slots },
  82                 { "color.remote", "<slot>", list_config_color_sideband_slots },
  83                 { "color.status", "<slot>", list_config_color_status_slots },
  84                 { "fsck", "<msg-id>", list_config_fsck_msg_ids },
  85                 { "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
  86                 { NULL, NULL, NULL }
  87         };
  88         const char **p;
  89         struct slot_expansion *e;
  90         struct string_list keys = STRING_LIST_INIT_DUP;
  91         int i;
  92
  93         for (p = config_name_list; *p; p++) {
  94                 const char *var = *p;
  95                 struct strbuf sb = STRBUF_INIT;
  96
  97                 for (e = slot_expansions; e->prefix; e++) {
  98
  99                         strbuf_reset(&sb);
 100                         strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
 101                         if (!strcasecmp(var, sb.buf)) {
 102                                 e->fn(&keys, e->prefix);
 103                                 e->found++;
 104                                 break;
 105                         }
 106                 }
 107                 strbuf_release(&sb);
 108                 if (!e->prefix)
 109                         string_list_append(&keys, var);
 110         }
 111
 112         for (e = slot_expansions; e->prefix; e++)
 113                 if (!e->found)
 114                         BUG("slot_expansion %s.%s is not used",
 115                             e->prefix, e->placeholder);
 116
 117         string_list_sort(&keys);
 118         for (i = 0; i < keys.nr; i++) {
 119                 const char *var = keys.items[i].string;
 120                 const char *wildcard, *tag, *cut;
 121
 122                 if (for_human) {
 123                         puts(var);
 124                         continue;
 125                 }
 126
 127                 wildcard = strchr(var, '*');
 128                 tag = strchr(var, '<');
 129
 130                 if (!wildcard && !tag) {
 131                         puts(var);
 132                         continue;
 133                 }
 134
 135                 if (wildcard && !tag)
 136                         cut = wildcard;
 137                 else if (!wildcard && tag)
 138                         cut = tag;
 139                 else
 140                         cut = wildcard < tag ? wildcard : tag;
 141
 142                 /*
 143                  * We may produce duplicates, but that's up to
 144                  * git-completion.bash to handle
 145                  */
 146                 printf("%.*s\n", (int)(cut - var), var);
 147         }
 148         string_list_clear(&keys, 0);
 149 }
 150
 151 static enum help_format parse_help_format(const char *format)
 152 {
 153         if (!strcmp(format, "man"))
 154                 return HELP_FORMAT_MAN;
 155         if (!strcmp(format, "info"))
 156                 return HELP_FORMAT_INFO;
 157         if (!strcmp(format, "web") || !strcmp(format, "html"))
 158                 return HELP_FORMAT_WEB;
 159         /*
 160          * Please update _git_config() in git-completion.bash when you
 161          * add new help formats.
 162          */
 163         die(_("unrecognized help format '%s'"), format);
 164 }
 165
 166 static const char *get_man_viewer_info(const char *name)
 167 {
 168         struct man_viewer_info_list *viewer;
 169
 170         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
 171         {
 172                 if (!strcasecmp(name, viewer->name))
 173                         return viewer->info;
 174         }
 175         return NULL;
 176 }
 177
 178 static int check_emacsclient_version(void)
 179 {
 180         struct strbuf buffer = STRBUF_INIT;
 181         struct child_process ec_process = CHILD_PROCESS_INIT;
 182         const char *argv_ec[] = { "emacsclient", "--version", NULL };
 183         int version;
 184
 185         /* emacsclient prints its version number on stderr */
 186         ec_process.argv = argv_ec;
 187         ec_process.err = -1;
 188         ec_process.stdout_to_stderr = 1;
 189         if (start_command(&ec_process))
 190                 return error(_("Failed to start emacsclient."));
 191
 192         strbuf_read(&buffer, ec_process.err, 20);
 193         close(ec_process.err);
 194
 195         /*
 196          * Don't bother checking return value, because "emacsclient --version"
 197          * seems to always exits with code 1.
 198          */
 199         finish_command(&ec_process);
 200
 201         if (!starts_with(buffer.buf, "emacsclient")) {
 202                 strbuf_release(&buffer);
 203                 return error(_("Failed to parse emacsclient version."));
 204         }
 205
 206         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 207         version = atoi(buffer.buf);
 208
 209         if (version < 22) {
 210                 strbuf_release(&buffer);
 211                 return error(_("emacsclient version '%d' too old (< 22)."),
 212                         version);
 213         }
 214
 215         strbuf_release(&buffer);
 216         return 0;
 217 }
 218
 219 static void exec_woman_emacs(const char *path, const char *page)
 220 {
 221         if (!check_emacsclient_version()) {
 222                 /* This works only with emacsclient version >= 22. */
 223                 struct strbuf man_page = STRBUF_INIT;
 224
 225                 if (!path)
 226                         path = "emacsclient";
 227                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 228                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 229                 warning_errno(_("failed to exec '%s'"), path);
 230                 strbuf_release(&man_page);
 231         }
 232 }
 233
 234 static void exec_man_konqueror(const char *path, const char *page)
 235 {
 236         const char *display = getenv("DISPLAY");
 237         if (display && *display) {
 238                 struct strbuf man_page = STRBUF_INIT;
 239                 const char *filename = "kfmclient";
 240
 241                 /* It's simpler to launch konqueror using kfmclient. */
 242                 if (path) {
 243                         size_t len;
 244                         if (strip_suffix(path, "/konqueror", &len))
 245                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 246                         filename = basename((char *)path);
 247                 } else
 248                         path = "kfmclient";
 249                 strbuf_addf(&man_page, "man:%s(1)", page);
 250                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 251                 warning_errno(_("failed to exec '%s'"), path);
 252                 strbuf_release(&man_page);
 253         }
 254 }
 255
 256 static void exec_man_man(const char *path, const char *page)
 257 {
 258         if (!path)
 259                 path = "man";
 260         execlp(path, "man", page, (char *)NULL);
 261         warning_errno(_("failed to exec '%s'"), path);
 262 }
 263
 264 static void exec_man_cmd(const char *cmd, const char *page)
 265 {
 266         struct strbuf shell_cmd = STRBUF_INIT;
 267         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 268         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 269         warning(_("failed to exec '%s'"), cmd);
 270         strbuf_release(&shell_cmd);
 271 }
 272
 273 static void add_man_viewer(const char *name)
 274 {
 275         struct man_viewer_list **p = &man_viewer_list;
 276
 277         while (*p)
 278                 p = &((*p)->next);
 279         FLEX_ALLOC_STR(*p, name, name);
 280 }
 281
 282 static int supported_man_viewer(const char *name, size_t len)
 283 {
 284         return (!strncasecmp("man", name, len) ||
 285                 !strncasecmp("woman", name, len) ||
 286                 !strncasecmp("konqueror", name, len));
 287 }
 288
 289 static void do_add_man_viewer_info(const char *name,
 290                                    size_t len,
 291                                    const char *value)
 292 {
 293         struct man_viewer_info_list *new_man_viewer;
 294         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
 295         new_man_viewer->info = xstrdup(value);
 296         new_man_viewer->next = man_viewer_info_list;
 297         man_viewer_info_list = new_man_viewer;
 298 }
 299
 300 static int add_man_viewer_path(const char *name,
 301                                size_t len,
 302                                const char *value)
 303 {
 304         if (supported_man_viewer(name, len))
 305                 do_add_man_viewer_info(name, len, value);
 306         else
 307                 warning(_("'%s': path for unsupported man viewer.\n"
 308                           "Please consider using 'man.<tool>.cmd' instead."),
 309                         name);
 310
 311         return 0;
 312 }
 313
 314 static int add_man_viewer_cmd(const char *name,
 315                               size_t len,
 316                               const char *value)
 317 {
 318         if (supported_man_viewer(name, len))
 319                 warning(_("'%s': cmd for supported man viewer.\n"
 320                           "Please consider using 'man.<tool>.path' instead."),
 321                         name);
 322         else
 323                 do_add_man_viewer_info(name, len, value);
 324
 325         return 0;
 326 }
 327
 328 static int add_man_viewer_info(const char *var, const char *value)
 329 {
 330         const char *name, *subkey;
 331         size_t namelen;
 332
 333         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 334                 return 0;
 335
 336         if (!strcmp(subkey, "path")) {
 337                 if (!value)
 338                         return config_error_nonbool(var);
 339                 return add_man_viewer_path(name, namelen, value);
 340         }
 341         if (!strcmp(subkey, "cmd")) {
 342                 if (!value)
 343                         return config_error_nonbool(var);
 344                 return add_man_viewer_cmd(name, namelen, value);
 345         }
 346
 347         return 0;
 348 }
 349
 350 static int git_help_config(const char *var, const char *value, void *cb)
 351 {
 352         if (starts_with(var, "column."))
 353                 return git_column_config(var, value, "help", &colopts);
 354         if (!strcmp(var, "help.format")) {
 355                 if (!value)
 356                         return config_error_nonbool(var);
 357                 help_format = parse_help_format(value);
 358                 return 0;
 359         }
 360         if (!strcmp(var, "help.htmlpath")) {
 361                 if (!value)
 362                         return config_error_nonbool(var);
 363                 html_path = xstrdup(value);
 364                 return 0;
 365         }
 366         if (!strcmp(var, "man.viewer")) {
 367                 if (!value)
 368                         return config_error_nonbool(var);
 369                 add_man_viewer(value);
 370                 return 0;
 371         }
 372         if (starts_with(var, "man."))
 373                 return add_man_viewer_info(var, value);
 374
 375         return git_default_config(var, value, cb);
 376 }
 377
 378 static struct cmdnames main_cmds, other_cmds;
 379
 380 static int is_git_command(const char *s)
 381 {
 382         if (is_builtin(s))
 383                 return 1;
 384
 385         load_command_list("git-", &main_cmds, &other_cmds);
 386         return is_in_cmdlist(&main_cmds, s) ||
 387                 is_in_cmdlist(&other_cmds, s);
 388 }
 389
 390 static const char *cmd_to_page(const char *git_cmd)
 391 {
 392         if (!git_cmd)
 393                 return "git";
 394         else if (starts_with(git_cmd, "git"))
 395                 return git_cmd;
 396         else if (is_git_command(git_cmd))
 397                 return xstrfmt("git-%s", git_cmd);
 398         else
 399                 return xstrfmt("git%s", git_cmd);
 400 }
 401
 402 static void setup_man_path(void)
 403 {
 404         struct strbuf new_path = STRBUF_INIT;
 405         const char *old_path = getenv("MANPATH");
 406         char *git_man_path = system_path(GIT_MAN_PATH);
 407
 408         /* We should always put ':' after our path. If there is no
 409          * old_path, the ':' at the end will let 'man' to try
 410          * system-wide paths after ours to find the manual page. If
 411          * there is old_path, we need ':' as delimiter. */
 412         strbuf_addstr(&new_path, git_man_path);
 413         strbuf_addch(&new_path, ':');
 414         if (old_path)
 415                 strbuf_addstr(&new_path, old_path);
 416
 417         free(git_man_path);
 418         setenv("MANPATH", new_path.buf, 1);
 419
 420         strbuf_release(&new_path);
 421 }
 422
 423 static void exec_viewer(const char *name, const char *page)
 424 {
 425         const char *info = get_man_viewer_info(name);
 426
 427         if (!strcasecmp(name, "man"))
 428                 exec_man_man(info, page);
 429         else if (!strcasecmp(name, "woman"))
 430                 exec_woman_emacs(info, page);
 431         else if (!strcasecmp(name, "konqueror"))
 432                 exec_man_konqueror(info, page);
 433         else if (info)
 434                 exec_man_cmd(info, page);
 435         else
 436                 warning(_("'%s': unknown man viewer."), name);
 437 }
 438
 439 static void show_man_page(const char *git_cmd)
 440 {
 441         struct man_viewer_list *viewer;
 442         const char *page = cmd_to_page(git_cmd);
 443         const char *fallback = getenv("GIT_MAN_VIEWER");
 444
 445         setup_man_path();
 446         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 447         {
 448                 exec_viewer(viewer->name, page); /* will return when unable */
 449         }
 450         if (fallback)
 451                 exec_viewer(fallback, page);
 452         exec_viewer("man", page);
 453         die(_("no man viewer handled the request"));
 454 }
 455
 456 static void show_info_page(const char *git_cmd)
 457 {
 458         const char *page = cmd_to_page(git_cmd);
 459         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 460         execlp("info", "info", "gitman", page, (char *)NULL);
 461         die(_("no info viewer handled the request"));
 462 }
 463
 464 static void get_html_page_path(struct strbuf *page_path, const char *page)
 465 {
 466         struct stat st;
 467         char *to_free = NULL;
 468
 469         if (!html_path)
 470                 html_path = to_free = system_path(GIT_HTML_PATH);
 471
 472         /* Check that we have a git documentation directory. */
 473         if (!strstr(html_path, "://")) {
 474                 if (stat(mkpath("%s/git.html", html_path), &st)
 475                     || !S_ISREG(st.st_mode))
 476                         die("'%s': not a documentation directory.", html_path);
 477         }
 478
 479         strbuf_init(page_path, 0);
 480         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 481         free(to_free);
 482 }
 483
 484 static void open_html(const char *path)
 485 {
 486         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 487 }
 488
 489 static void show_html_page(const char *git_cmd)
 490 {
 491         const char *page = cmd_to_page(git_cmd);
 492         struct strbuf page_path; /* it leaks but we exec bellow */
 493
 494         get_html_page_path(&page_path, page);
 495
 496         open_html(page_path.buf);
 497 }
 498
 499 static const char *check_git_cmd(const char* cmd)
 500 {
 501         char *alias;
 502
 503         if (is_git_command(cmd))
 504                 return cmd;
 505
 506         alias = alias_lookup(cmd);
 507         if (alias) {
 508                 const char **argv;
 509                 int count;
 510
 511                 /*
 512                  * handle_builtin() in git.c rewrites "git cmd --help"
 513                  * to "git help --exclude-guides cmd", so we can use
 514                  * exclude_guides to distinguish "git cmd --help" from
 515                  * "git help cmd". In the latter case, or if cmd is an
 516                  * alias for a shell command, just print the alias
 517                  * definition.
 518                  */
 519                 if (!exclude_guides || alias[0] == '!') {
 520                         printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
 521                         free(alias);
 522                         exit(0);
 523                 }
 524                 /*
 525                  * Otherwise, we pretend that the command was "git
 526                  * word0 --help". We use split_cmdline() to get the
 527                  * first word of the alias, to ensure that we use the
 528                  * same rules as when the alias is actually
 529                  * used. split_cmdline() modifies alias in-place.
 530                  */
 531                 fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
 532                 count = split_cmdline(alias, &argv);
 533                 if (count < 0)
 534                         die(_("bad alias.%s string: %s"), cmd,
 535                             split_cmdline_strerror(count));
 536                 free(argv);
 537                 UNLEAK(alias);
 538                 return alias;
 539         }
 540
 541         if (exclude_guides)
 542                 return help_unknown_cmd(cmd);
 543
 544         return cmd;
 545 }
 546
 547 int cmd_help(int argc, const char **argv, const char *prefix)
 548 {
 549         int nongit;
 550         enum help_format parsed_help_format;
 551
 552         argc = parse_options(argc, argv, prefix, builtin_help_options,
 553                         builtin_help_usage, 0);
 554         parsed_help_format = help_format;
 555
 556         if (show_all) {
 557                 git_config(git_help_config, NULL);
 558                 if (verbose) {
 559                         setup_pager();
 560                         list_all_cmds_help();
 561                         return 0;
 562                 }
 563                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 564                 load_command_list("git-", &main_cmds, &other_cmds);
 565                 list_commands(colopts, &main_cmds, &other_cmds);
 566         }
 567
 568         if (show_config) {
 569                 int for_human = show_config == 1;
 570
 571                 if (!for_human) {
 572                         list_config_help(for_human);
 573                         return 0;
 574                 }
 575                 setup_pager();
 576                 list_config_help(for_human);
 577                 printf("\n%s\n", _("'git help config' for more information"));
 578                 return 0;
 579         }
 580
 581         if (show_guides)
 582                 list_common_guides_help();
 583
 584         if (show_all || show_guides) {
 585                 printf("%s\n", _(git_more_info_string));
 586                 /*
 587                 * We're done. Ignore any remaining args
 588                 */
 589                 return 0;
 590         }
 591
 592         if (!argv[0]) {
 593                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 594                 list_common_cmds_help();
 595                 printf("\n%s\n", _(git_more_info_string));
 596                 return 0;
 597         }
 598
 599         setup_git_directory_gently(&nongit);
 600         git_config(git_help_config, NULL);
 601
 602         if (parsed_help_format != HELP_FORMAT_NONE)
 603                 help_format = parsed_help_format;
 604         if (help_format == HELP_FORMAT_NONE)
 605                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 606
 607         argv[0] = check_git_cmd(argv[0]);
 608
 609         switch (help_format) {
 610         case HELP_FORMAT_NONE:
 611         case HELP_FORMAT_MAN:
 612                 show_man_page(argv[0]);
 613                 break;
 614         case HELP_FORMAT_INFO:
 615                 show_info_page(argv[0]);
 616                 break;
 617         case HELP_FORMAT_WEB:
 618                 show_html_page(argv[0]);
 619                 break;
 620         }
 621
 622         return 0;
 623 }