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 "config-list.h"
  11 #include "help.h"
  12 #include "alias.h"
  13
  14 #ifndef DEFAULT_HELP_FORMAT
  15 #define DEFAULT_HELP_FORMAT "man"
  16 #endif
  17
  18 static struct man_viewer_list {
  19         struct man_viewer_list *next;
  20         char name[FLEX_ARRAY];
  21 } *man_viewer_list;
  22
  23 static struct man_viewer_info_list {
  24         struct man_viewer_info_list *next;
  25         const char *info;
  26         char name[FLEX_ARRAY];
  27 } *man_viewer_info_list;
  28
  29 enum help_format {
  30         HELP_FORMAT_NONE,
  31         HELP_FORMAT_MAN,
  32         HELP_FORMAT_INFO,
  33         HELP_FORMAT_WEB
  34 };
  35
  36 enum show_config_type {
  37         SHOW_CONFIG_HUMAN,
  38         SHOW_CONFIG_VARS,
  39         SHOW_CONFIG_SECTIONS,
  40 };
  41
  42 static enum help_action {
  43         HELP_ACTION_ALL = 1,
  44         HELP_ACTION_GUIDES,
  45         HELP_ACTION_CONFIG,
  46         HELP_ACTION_CONFIG_FOR_COMPLETION,
  47         HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION,
  48 } cmd_mode;
  49
  50 static const char *html_path;
  51 static int verbose = 1;
  52 static enum help_format help_format = HELP_FORMAT_NONE;
  53 static int exclude_guides;
  54 static struct option builtin_help_options[] = {
  55         OPT_CMDMODE('a', "all", &cmd_mode, N_("print all available commands"),
  56                     HELP_ACTION_ALL),
  57         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
  58         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  59         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  60                         HELP_FORMAT_WEB),
  61         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  62                         HELP_FORMAT_INFO),
  63         OPT__VERBOSE(&verbose, N_("print command description")),
  64
  65         OPT_CMDMODE('g', "guides", &cmd_mode, N_("print list of useful guides"),
  66                     HELP_ACTION_GUIDES),
  67         OPT_CMDMODE('c', "config", &cmd_mode, N_("print all configuration variable names"),
  68                     HELP_ACTION_CONFIG),
  69         OPT_CMDMODE_F(0, "config-for-completion", &cmd_mode, "",
  70                     HELP_ACTION_CONFIG_FOR_COMPLETION, PARSE_OPT_HIDDEN),
  71         OPT_CMDMODE_F(0, "config-sections-for-completion", &cmd_mode, "",
  72                     HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION, PARSE_OPT_HIDDEN),
  73
  74         OPT_END(),
  75 };
  76
  77 static const char * const builtin_help_usage[] = {
  78         N_("git help [-a|--all] [--[no-]verbose]]\n"
  79            "         [[-i|--info] [-m|--man] [-w|--web]] [<command>]"),
  80         N_("git help [-g|--guides]"),
  81         N_("git help [-c|--config]"),
  82         NULL
  83 };
  84
  85 struct slot_expansion {
  86         const char *prefix;
  87         const char *placeholder;
  88         void (*fn)(struct string_list *list, const char *prefix);
  89         int found;
  90 };
  91
  92 static void list_config_help(enum show_config_type type)
  93 {
  94         struct slot_expansion slot_expansions[] = {
  95                 { "advice", "*", list_config_advices },
  96                 { "color.branch", "<slot>", list_config_color_branch_slots },
  97                 { "color.decorate", "<slot>", list_config_color_decorate_slots },
  98                 { "color.diff", "<slot>", list_config_color_diff_slots },
  99                 { "color.grep", "<slot>", list_config_color_grep_slots },
 100                 { "color.interactive", "<slot>", list_config_color_interactive_slots },
 101                 { "color.remote", "<slot>", list_config_color_sideband_slots },
 102                 { "color.status", "<slot>", list_config_color_status_slots },
 103                 { "fsck", "<msg-id>", list_config_fsck_msg_ids },
 104                 { "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
 105                 { NULL, NULL, NULL }
 106         };
 107         const char **p;
 108         struct slot_expansion *e;
 109         struct string_list keys = STRING_LIST_INIT_DUP;
 110         struct string_list keys_uniq = STRING_LIST_INIT_DUP;
 111         struct string_list_item *item;
 112         int i;
 113
 114         for (p = config_name_list; *p; p++) {
 115                 const char *var = *p;
 116                 struct strbuf sb = STRBUF_INIT;
 117
 118                 for (e = slot_expansions; e->prefix; e++) {
 119
 120                         strbuf_reset(&sb);
 121                         strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
 122                         if (!strcasecmp(var, sb.buf)) {
 123                                 e->fn(&keys, e->prefix);
 124                                 e->found++;
 125                                 break;
 126                         }
 127                 }
 128                 strbuf_release(&sb);
 129                 if (!e->prefix)
 130                         string_list_append(&keys, var);
 131         }
 132
 133         for (e = slot_expansions; e->prefix; e++)
 134                 if (!e->found)
 135                         BUG("slot_expansion %s.%s is not used",
 136                             e->prefix, e->placeholder);
 137
 138         string_list_sort(&keys);
 139         for (i = 0; i < keys.nr; i++) {
 140                 const char *var = keys.items[i].string;
 141                 const char *wildcard, *tag, *cut;
 142                 const char *dot = NULL;
 143                 struct strbuf sb = STRBUF_INIT;
 144
 145                 switch (type) {
 146                 case SHOW_CONFIG_HUMAN:
 147                         puts(var);
 148                         continue;
 149                 case SHOW_CONFIG_SECTIONS:
 150                         dot = strchr(var, '.');
 151                         break;
 152                 case SHOW_CONFIG_VARS:
 153                         break;
 154                 }
 155                 wildcard = strchr(var, '*');
 156                 tag = strchr(var, '<');
 157
 158                 if (!dot && !wildcard && !tag) {
 159                         string_list_append(&keys_uniq, var);
 160                         continue;
 161                 }
 162
 163                 if (dot)
 164                         cut = dot;
 165                 else if (wildcard && !tag)
 166                         cut = wildcard;
 167                 else if (!wildcard && tag)
 168                         cut = tag;
 169                 else
 170                         cut = wildcard < tag ? wildcard : tag;
 171
 172                 strbuf_add(&sb, var, cut - var);
 173                 string_list_append(&keys_uniq, sb.buf);
 174                 strbuf_release(&sb);
 175
 176         }
 177         string_list_clear(&keys, 0);
 178         string_list_remove_duplicates(&keys_uniq, 0);
 179         for_each_string_list_item(item, &keys_uniq)
 180                 puts(item->string);
 181         string_list_clear(&keys_uniq, 0);
 182 }
 183
 184 static enum help_format parse_help_format(const char *format)
 185 {
 186         if (!strcmp(format, "man"))
 187                 return HELP_FORMAT_MAN;
 188         if (!strcmp(format, "info"))
 189                 return HELP_FORMAT_INFO;
 190         if (!strcmp(format, "web") || !strcmp(format, "html"))
 191                 return HELP_FORMAT_WEB;
 192         /*
 193          * Please update _git_config() in git-completion.bash when you
 194          * add new help formats.
 195          */
 196         die(_("unrecognized help format '%s'"), format);
 197 }
 198
 199 static const char *get_man_viewer_info(const char *name)
 200 {
 201         struct man_viewer_info_list *viewer;
 202
 203         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
 204         {
 205                 if (!strcasecmp(name, viewer->name))
 206                         return viewer->info;
 207         }
 208         return NULL;
 209 }
 210
 211 static int check_emacsclient_version(void)
 212 {
 213         struct strbuf buffer = STRBUF_INIT;
 214         struct child_process ec_process = CHILD_PROCESS_INIT;
 215         int version;
 216
 217         /* emacsclient prints its version number on stderr */
 218         strvec_pushl(&ec_process.args, "emacsclient", "--version", NULL);
 219         ec_process.err = -1;
 220         ec_process.stdout_to_stderr = 1;
 221         if (start_command(&ec_process))
 222                 return error(_("Failed to start emacsclient."));
 223
 224         strbuf_read(&buffer, ec_process.err, 20);
 225         close(ec_process.err);
 226
 227         /*
 228          * Don't bother checking return value, because "emacsclient --version"
 229          * seems to always exits with code 1.
 230          */
 231         finish_command(&ec_process);
 232
 233         if (!starts_with(buffer.buf, "emacsclient")) {
 234                 strbuf_release(&buffer);
 235                 return error(_("Failed to parse emacsclient version."));
 236         }
 237
 238         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 239         version = atoi(buffer.buf);
 240
 241         if (version < 22) {
 242                 strbuf_release(&buffer);
 243                 return error(_("emacsclient version '%d' too old (< 22)."),
 244                         version);
 245         }
 246
 247         strbuf_release(&buffer);
 248         return 0;
 249 }
 250
 251 static void exec_woman_emacs(const char *path, const char *page)
 252 {
 253         if (!check_emacsclient_version()) {
 254                 /* This works only with emacsclient version >= 22. */
 255                 struct strbuf man_page = STRBUF_INIT;
 256
 257                 if (!path)
 258                         path = "emacsclient";
 259                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 260                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 261                 warning_errno(_("failed to exec '%s'"), path);
 262                 strbuf_release(&man_page);
 263         }
 264 }
 265
 266 static void exec_man_konqueror(const char *path, const char *page)
 267 {
 268         const char *display = getenv("DISPLAY");
 269         if (display && *display) {
 270                 struct strbuf man_page = STRBUF_INIT;
 271                 const char *filename = "kfmclient";
 272
 273                 /* It's simpler to launch konqueror using kfmclient. */
 274                 if (path) {
 275                         size_t len;
 276                         if (strip_suffix(path, "/konqueror", &len))
 277                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 278                         filename = basename((char *)path);
 279                 } else
 280                         path = "kfmclient";
 281                 strbuf_addf(&man_page, "man:%s(1)", page);
 282                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 283                 warning_errno(_("failed to exec '%s'"), path);
 284                 strbuf_release(&man_page);
 285         }
 286 }
 287
 288 static void exec_man_man(const char *path, const char *page)
 289 {
 290         if (!path)
 291                 path = "man";
 292         execlp(path, "man", page, (char *)NULL);
 293         warning_errno(_("failed to exec '%s'"), path);
 294 }
 295
 296 static void exec_man_cmd(const char *cmd, const char *page)
 297 {
 298         struct strbuf shell_cmd = STRBUF_INIT;
 299         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 300         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 301         warning(_("failed to exec '%s'"), cmd);
 302         strbuf_release(&shell_cmd);
 303 }
 304
 305 static void add_man_viewer(const char *name)
 306 {
 307         struct man_viewer_list **p = &man_viewer_list;
 308
 309         while (*p)
 310                 p = &((*p)->next);
 311         FLEX_ALLOC_STR(*p, name, name);
 312 }
 313
 314 static int supported_man_viewer(const char *name, size_t len)
 315 {
 316         return (!strncasecmp("man", name, len) ||
 317                 !strncasecmp("woman", name, len) ||
 318                 !strncasecmp("konqueror", name, len));
 319 }
 320
 321 static void do_add_man_viewer_info(const char *name,
 322                                    size_t len,
 323                                    const char *value)
 324 {
 325         struct man_viewer_info_list *new_man_viewer;
 326         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
 327         new_man_viewer->info = xstrdup(value);
 328         new_man_viewer->next = man_viewer_info_list;
 329         man_viewer_info_list = new_man_viewer;
 330 }
 331
 332 static int add_man_viewer_path(const char *name,
 333                                size_t len,
 334                                const char *value)
 335 {
 336         if (supported_man_viewer(name, len))
 337                 do_add_man_viewer_info(name, len, value);
 338         else
 339                 warning(_("'%s': path for unsupported man viewer.\n"
 340                           "Please consider using 'man.<tool>.cmd' instead."),
 341                         name);
 342
 343         return 0;
 344 }
 345
 346 static int add_man_viewer_cmd(const char *name,
 347                               size_t len,
 348                               const char *value)
 349 {
 350         if (supported_man_viewer(name, len))
 351                 warning(_("'%s': cmd for supported man viewer.\n"
 352                           "Please consider using 'man.<tool>.path' instead."),
 353                         name);
 354         else
 355                 do_add_man_viewer_info(name, len, value);
 356
 357         return 0;
 358 }
 359
 360 static int add_man_viewer_info(const char *var, const char *value)
 361 {
 362         const char *name, *subkey;
 363         size_t namelen;
 364
 365         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 366                 return 0;
 367
 368         if (!strcmp(subkey, "path")) {
 369                 if (!value)
 370                         return config_error_nonbool(var);
 371                 return add_man_viewer_path(name, namelen, value);
 372         }
 373         if (!strcmp(subkey, "cmd")) {
 374                 if (!value)
 375                         return config_error_nonbool(var);
 376                 return add_man_viewer_cmd(name, namelen, value);
 377         }
 378
 379         return 0;
 380 }
 381
 382 static int git_help_config(const char *var, const char *value, void *cb)
 383 {
 384         if (!strcmp(var, "help.format")) {
 385                 if (!value)
 386                         return config_error_nonbool(var);
 387                 help_format = parse_help_format(value);
 388                 return 0;
 389         }
 390         if (!strcmp(var, "help.htmlpath")) {
 391                 if (!value)
 392                         return config_error_nonbool(var);
 393                 html_path = xstrdup(value);
 394                 return 0;
 395         }
 396         if (!strcmp(var, "man.viewer")) {
 397                 if (!value)
 398                         return config_error_nonbool(var);
 399                 add_man_viewer(value);
 400                 return 0;
 401         }
 402         if (starts_with(var, "man."))
 403                 return add_man_viewer_info(var, value);
 404
 405         return git_default_config(var, value, cb);
 406 }
 407
 408 static struct cmdnames main_cmds, other_cmds;
 409
 410 static int is_git_command(const char *s)
 411 {
 412         if (is_builtin(s))
 413                 return 1;
 414
 415         load_command_list("git-", &main_cmds, &other_cmds);
 416         return is_in_cmdlist(&main_cmds, s) ||
 417                 is_in_cmdlist(&other_cmds, s);
 418 }
 419
 420 static const char *cmd_to_page(const char *git_cmd)
 421 {
 422         if (!git_cmd)
 423                 return "git";
 424         else if (starts_with(git_cmd, "git"))
 425                 return git_cmd;
 426         else if (is_git_command(git_cmd))
 427                 return xstrfmt("git-%s", git_cmd);
 428         else
 429                 return xstrfmt("git%s", git_cmd);
 430 }
 431
 432 static void setup_man_path(void)
 433 {
 434         struct strbuf new_path = STRBUF_INIT;
 435         const char *old_path = getenv("MANPATH");
 436         char *git_man_path = system_path(GIT_MAN_PATH);
 437
 438         /* We should always put ':' after our path. If there is no
 439          * old_path, the ':' at the end will let 'man' to try
 440          * system-wide paths after ours to find the manual page. If
 441          * there is old_path, we need ':' as delimiter. */
 442         strbuf_addstr(&new_path, git_man_path);
 443         strbuf_addch(&new_path, ':');
 444         if (old_path)
 445                 strbuf_addstr(&new_path, old_path);
 446
 447         free(git_man_path);
 448         setenv("MANPATH", new_path.buf, 1);
 449
 450         strbuf_release(&new_path);
 451 }
 452
 453 static void exec_viewer(const char *name, const char *page)
 454 {
 455         const char *info = get_man_viewer_info(name);
 456
 457         if (!strcasecmp(name, "man"))
 458                 exec_man_man(info, page);
 459         else if (!strcasecmp(name, "woman"))
 460                 exec_woman_emacs(info, page);
 461         else if (!strcasecmp(name, "konqueror"))
 462                 exec_man_konqueror(info, page);
 463         else if (info)
 464                 exec_man_cmd(info, page);
 465         else
 466                 warning(_("'%s': unknown man viewer."), name);
 467 }
 468
 469 static void show_man_page(const char *page)
 470 {
 471         struct man_viewer_list *viewer;
 472         const char *fallback = getenv("GIT_MAN_VIEWER");
 473
 474         setup_man_path();
 475         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 476         {
 477                 exec_viewer(viewer->name, page); /* will return when unable */
 478         }
 479         if (fallback)
 480                 exec_viewer(fallback, page);
 481         exec_viewer("man", page);
 482         die(_("no man viewer handled the request"));
 483 }
 484
 485 static void show_info_page(const char *page)
 486 {
 487         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 488         execlp("info", "info", "gitman", page, (char *)NULL);
 489         die(_("no info viewer handled the request"));
 490 }
 491
 492 static void get_html_page_path(struct strbuf *page_path, const char *page)
 493 {
 494         struct stat st;
 495         char *to_free = NULL;
 496
 497         if (!html_path)
 498                 html_path = to_free = system_path(GIT_HTML_PATH);
 499
 500         /*
 501          * Check that the page we're looking for exists.
 502          */
 503         if (!strstr(html_path, "://")) {
 504                 if (stat(mkpath("%s/%s.html", html_path, page), &st)
 505                     || !S_ISREG(st.st_mode))
 506                         die("'%s/%s.html': documentation file not found.",
 507                                 html_path, page);
 508         }
 509
 510         strbuf_init(page_path, 0);
 511         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 512         free(to_free);
 513 }
 514
 515 static void open_html(const char *path)
 516 {
 517         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 518 }
 519
 520 static void show_html_page(const char *page)
 521 {
 522         struct strbuf page_path; /* it leaks but we exec bellow */
 523
 524         get_html_page_path(&page_path, page);
 525
 526         open_html(page_path.buf);
 527 }
 528
 529 static const char *check_git_cmd(const char* cmd)
 530 {
 531         char *alias;
 532
 533         if (is_git_command(cmd))
 534                 return cmd;
 535
 536         alias = alias_lookup(cmd);
 537         if (alias) {
 538                 const char **argv;
 539                 int count;
 540
 541                 /*
 542                  * handle_builtin() in git.c rewrites "git cmd --help"
 543                  * to "git help --exclude-guides cmd", so we can use
 544                  * exclude_guides to distinguish "git cmd --help" from
 545                  * "git help cmd". In the latter case, or if cmd is an
 546                  * alias for a shell command, just print the alias
 547                  * definition.
 548                  */
 549                 if (!exclude_guides || alias[0] == '!') {
 550                         printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
 551                         free(alias);
 552                         exit(0);
 553                 }
 554                 /*
 555                  * Otherwise, we pretend that the command was "git
 556                  * word0 --help". We use split_cmdline() to get the
 557                  * first word of the alias, to ensure that we use the
 558                  * same rules as when the alias is actually
 559                  * used. split_cmdline() modifies alias in-place.
 560                  */
 561                 fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
 562                 count = split_cmdline(alias, &argv);
 563                 if (count < 0)
 564                         die(_("bad alias.%s string: %s"), cmd,
 565                             split_cmdline_strerror(count));
 566                 free(argv);
 567                 UNLEAK(alias);
 568                 return alias;
 569         }
 570
 571         if (exclude_guides)
 572                 return help_unknown_cmd(cmd);
 573
 574         return cmd;
 575 }
 576
 577 static void no_extra_argc(int argc)
 578 {
 579         if (argc)
 580                 usage_msg_opt(_("this option doesn't take any other arguments"),
 581                               builtin_help_usage, builtin_help_options);
 582 }
 583
 584 int cmd_help(int argc, const char **argv, const char *prefix)
 585 {
 586         int nongit;
 587         enum help_format parsed_help_format;
 588         const char *page;
 589
 590         argc = parse_options(argc, argv, prefix, builtin_help_options,
 591                         builtin_help_usage, 0);
 592         parsed_help_format = help_format;
 593
 594         switch (cmd_mode) {
 595         case HELP_ACTION_ALL:
 596                 if (verbose) {
 597                         setup_pager();
 598                         list_all_cmds_help();
 599                         return 0;
 600                 }
 601                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 602                 load_command_list("git-", &main_cmds, &other_cmds);
 603                 list_commands(&main_cmds, &other_cmds);
 604                 printf("%s\n", _(git_more_info_string));
 605                 break;
 606         case HELP_ACTION_GUIDES:
 607                 no_extra_argc(argc);
 608                 list_guides_help();
 609                 printf("%s\n", _(git_more_info_string));
 610                 return 0;
 611         case HELP_ACTION_CONFIG_FOR_COMPLETION:
 612                 no_extra_argc(argc);
 613                 list_config_help(SHOW_CONFIG_VARS);
 614                 return 0;
 615         case HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION:
 616                 no_extra_argc(argc);
 617                 list_config_help(SHOW_CONFIG_SECTIONS);
 618                 return 0;
 619         case HELP_ACTION_CONFIG:
 620                 no_extra_argc(argc);
 621                 setup_pager();
 622                 list_config_help(SHOW_CONFIG_HUMAN);
 623                 printf("\n%s\n", _("'git help config' for more information"));
 624                 return 0;
 625         }
 626
 627         if (!argv[0]) {
 628                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 629                 list_common_cmds_help();
 630                 printf("\n%s\n", _(git_more_info_string));
 631                 return 0;
 632         }
 633
 634         setup_git_directory_gently(&nongit);
 635         git_config(git_help_config, NULL);
 636
 637         if (parsed_help_format != HELP_FORMAT_NONE)
 638                 help_format = parsed_help_format;
 639         if (help_format == HELP_FORMAT_NONE)
 640                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 641
 642         argv[0] = check_git_cmd(argv[0]);
 643
 644         page = cmd_to_page(argv[0]);
 645         switch (help_format) {
 646         case HELP_FORMAT_NONE:
 647         case HELP_FORMAT_MAN:
 648                 show_man_page(page);
 649                 break;
 650         case HELP_FORMAT_INFO:
 651                 show_info_page(page);
 652                 break;
 653         case HELP_FORMAT_WEB:
 654                 show_html_page(page);
 655                 break;
 656         }
 657
 658         return 0;
 659 }