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 "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 static const char *html_path;
  37
  38 static int show_all = 0;
  39 static int show_guides = 0;
  40 static int verbose;
  41 static unsigned int colopts;
  42 static enum help_format help_format = HELP_FORMAT_NONE;
  43 static int exclude_guides;
  44 static struct option builtin_help_options[] = {
  45         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
  46         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
  47         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
  48         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  49         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  50                         HELP_FORMAT_WEB),
  51         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  52                         HELP_FORMAT_INFO),
  53         OPT__VERBOSE(&verbose, N_("print command description")),
  54         OPT_END(),
  55 };
  56
  57 static const char * const builtin_help_usage[] = {
  58         N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
  59         NULL
  60 };
  61
  62 static enum help_format parse_help_format(const char *format)
  63 {
  64         if (!strcmp(format, "man"))
  65                 return HELP_FORMAT_MAN;
  66         if (!strcmp(format, "info"))
  67                 return HELP_FORMAT_INFO;
  68         if (!strcmp(format, "web") || !strcmp(format, "html"))
  69                 return HELP_FORMAT_WEB;
  70         die(_("unrecognized help format '%s'"), format);
  71 }
  72
  73 static const char *get_man_viewer_info(const char *name)
  74 {
  75         struct man_viewer_info_list *viewer;
  76
  77         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  78         {
  79                 if (!strcasecmp(name, viewer->name))
  80                         return viewer->info;
  81         }
  82         return NULL;
  83 }
  84
  85 static int check_emacsclient_version(void)
  86 {
  87         struct strbuf buffer = STRBUF_INIT;
  88         struct child_process ec_process = CHILD_PROCESS_INIT;
  89         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  90         int version;
  91
  92         /* emacsclient prints its version number on stderr */
  93         ec_process.argv = argv_ec;
  94         ec_process.err = -1;
  95         ec_process.stdout_to_stderr = 1;
  96         if (start_command(&ec_process))
  97                 return error(_("Failed to start emacsclient."));
  98
  99         strbuf_read(&buffer, ec_process.err, 20);
 100         close(ec_process.err);
 101
 102         /*
 103          * Don't bother checking return value, because "emacsclient --version"
 104          * seems to always exits with code 1.
 105          */
 106         finish_command(&ec_process);
 107
 108         if (!starts_with(buffer.buf, "emacsclient")) {
 109                 strbuf_release(&buffer);
 110                 return error(_("Failed to parse emacsclient version."));
 111         }
 112
 113         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 114         version = atoi(buffer.buf);
 115
 116         if (version < 22) {
 117                 strbuf_release(&buffer);
 118                 return error(_("emacsclient version '%d' too old (< 22)."),
 119                         version);
 120         }
 121
 122         strbuf_release(&buffer);
 123         return 0;
 124 }
 125
 126 static void exec_woman_emacs(const char *path, const char *page)
 127 {
 128         if (!check_emacsclient_version()) {
 129                 /* This works only with emacsclient version >= 22. */
 130                 struct strbuf man_page = STRBUF_INIT;
 131
 132                 if (!path)
 133                         path = "emacsclient";
 134                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 135                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 136                 warning_errno(_("failed to exec '%s'"), path);
 137                 strbuf_release(&man_page);
 138         }
 139 }
 140
 141 static void exec_man_konqueror(const char *path, const char *page)
 142 {
 143         const char *display = getenv("DISPLAY");
 144         if (display && *display) {
 145                 struct strbuf man_page = STRBUF_INIT;
 146                 const char *filename = "kfmclient";
 147
 148                 /* It's simpler to launch konqueror using kfmclient. */
 149                 if (path) {
 150                         size_t len;
 151                         if (strip_suffix(path, "/konqueror", &len))
 152                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 153                         filename = basename((char *)path);
 154                 } else
 155                         path = "kfmclient";
 156                 strbuf_addf(&man_page, "man:%s(1)", page);
 157                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 158                 warning_errno(_("failed to exec '%s'"), path);
 159                 strbuf_release(&man_page);
 160         }
 161 }
 162
 163 static void exec_man_man(const char *path, const char *page)
 164 {
 165         if (!path)
 166                 path = "man";
 167         execlp(path, "man", page, (char *)NULL);
 168         warning_errno(_("failed to exec '%s'"), path);
 169 }
 170
 171 static void exec_man_cmd(const char *cmd, const char *page)
 172 {
 173         struct strbuf shell_cmd = STRBUF_INIT;
 174         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 175         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 176         warning(_("failed to exec '%s'"), cmd);
 177         strbuf_release(&shell_cmd);
 178 }
 179
 180 static void add_man_viewer(const char *name)
 181 {
 182         struct man_viewer_list **p = &man_viewer_list;
 183
 184         while (*p)
 185                 p = &((*p)->next);
 186         FLEX_ALLOC_STR(*p, name, name);
 187 }
 188
 189 static int supported_man_viewer(const char *name, size_t len)
 190 {
 191         return (!strncasecmp("man", name, len) ||
 192                 !strncasecmp("woman", name, len) ||
 193                 !strncasecmp("konqueror", name, len));
 194 }
 195
 196 static void do_add_man_viewer_info(const char *name,
 197                                    size_t len,
 198                                    const char *value)
 199 {
 200         struct man_viewer_info_list *new_man_viewer;
 201         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
 202         new_man_viewer->info = xstrdup(value);
 203         new_man_viewer->next = man_viewer_info_list;
 204         man_viewer_info_list = new_man_viewer;
 205 }
 206
 207 static int add_man_viewer_path(const char *name,
 208                                size_t len,
 209                                const char *value)
 210 {
 211         if (supported_man_viewer(name, len))
 212                 do_add_man_viewer_info(name, len, value);
 213         else
 214                 warning(_("'%s': path for unsupported man viewer.\n"
 215                           "Please consider using 'man.<tool>.cmd' instead."),
 216                         name);
 217
 218         return 0;
 219 }
 220
 221 static int add_man_viewer_cmd(const char *name,
 222                               size_t len,
 223                               const char *value)
 224 {
 225         if (supported_man_viewer(name, len))
 226                 warning(_("'%s': cmd for supported man viewer.\n"
 227                           "Please consider using 'man.<tool>.path' instead."),
 228                         name);
 229         else
 230                 do_add_man_viewer_info(name, len, value);
 231
 232         return 0;
 233 }
 234
 235 static int add_man_viewer_info(const char *var, const char *value)
 236 {
 237         const char *name, *subkey;
 238         int namelen;
 239
 240         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 241                 return 0;
 242
 243         if (!strcmp(subkey, "path")) {
 244                 if (!value)
 245                         return config_error_nonbool(var);
 246                 return add_man_viewer_path(name, namelen, value);
 247         }
 248         if (!strcmp(subkey, "cmd")) {
 249                 if (!value)
 250                         return config_error_nonbool(var);
 251                 return add_man_viewer_cmd(name, namelen, value);
 252         }
 253
 254         return 0;
 255 }
 256
 257 static int git_help_config(const char *var, const char *value, void *cb)
 258 {
 259         if (starts_with(var, "column."))
 260                 return git_column_config(var, value, "help", &colopts);
 261         if (!strcmp(var, "help.format")) {
 262                 if (!value)
 263                         return config_error_nonbool(var);
 264                 help_format = parse_help_format(value);
 265                 return 0;
 266         }
 267         if (!strcmp(var, "help.htmlpath")) {
 268                 if (!value)
 269                         return config_error_nonbool(var);
 270                 html_path = xstrdup(value);
 271                 return 0;
 272         }
 273         if (!strcmp(var, "man.viewer")) {
 274                 if (!value)
 275                         return config_error_nonbool(var);
 276                 add_man_viewer(value);
 277                 return 0;
 278         }
 279         if (starts_with(var, "man."))
 280                 return add_man_viewer_info(var, value);
 281
 282         return git_default_config(var, value, cb);
 283 }
 284
 285 static struct cmdnames main_cmds, other_cmds;
 286
 287 static int is_git_command(const char *s)
 288 {
 289         if (is_builtin(s))
 290                 return 1;
 291
 292         load_command_list("git-", &main_cmds, &other_cmds);
 293         return is_in_cmdlist(&main_cmds, s) ||
 294                 is_in_cmdlist(&other_cmds, s);
 295 }
 296
 297 static const char *cmd_to_page(const char *git_cmd)
 298 {
 299         if (!git_cmd)
 300                 return "git";
 301         else if (starts_with(git_cmd, "git"))
 302                 return git_cmd;
 303         else if (is_git_command(git_cmd))
 304                 return xstrfmt("git-%s", git_cmd);
 305         else
 306                 return xstrfmt("git%s", git_cmd);
 307 }
 308
 309 static void setup_man_path(void)
 310 {
 311         struct strbuf new_path = STRBUF_INIT;
 312         const char *old_path = getenv("MANPATH");
 313         char *git_man_path = system_path(GIT_MAN_PATH);
 314
 315         /* We should always put ':' after our path. If there is no
 316          * old_path, the ':' at the end will let 'man' to try
 317          * system-wide paths after ours to find the manual page. If
 318          * there is old_path, we need ':' as delimiter. */
 319         strbuf_addstr(&new_path, git_man_path);
 320         strbuf_addch(&new_path, ':');
 321         if (old_path)
 322                 strbuf_addstr(&new_path, old_path);
 323
 324         free(git_man_path);
 325         setenv("MANPATH", new_path.buf, 1);
 326
 327         strbuf_release(&new_path);
 328 }
 329
 330 static void exec_viewer(const char *name, const char *page)
 331 {
 332         const char *info = get_man_viewer_info(name);
 333
 334         if (!strcasecmp(name, "man"))
 335                 exec_man_man(info, page);
 336         else if (!strcasecmp(name, "woman"))
 337                 exec_woman_emacs(info, page);
 338         else if (!strcasecmp(name, "konqueror"))
 339                 exec_man_konqueror(info, page);
 340         else if (info)
 341                 exec_man_cmd(info, page);
 342         else
 343                 warning(_("'%s': unknown man viewer."), name);
 344 }
 345
 346 static void show_man_page(const char *git_cmd)
 347 {
 348         struct man_viewer_list *viewer;
 349         const char *page = cmd_to_page(git_cmd);
 350         const char *fallback = getenv("GIT_MAN_VIEWER");
 351
 352         setup_man_path();
 353         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 354         {
 355                 exec_viewer(viewer->name, page); /* will return when unable */
 356         }
 357         if (fallback)
 358                 exec_viewer(fallback, page);
 359         exec_viewer("man", page);
 360         die(_("no man viewer handled the request"));
 361 }
 362
 363 static void show_info_page(const char *git_cmd)
 364 {
 365         const char *page = cmd_to_page(git_cmd);
 366         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 367         execlp("info", "info", "gitman", page, (char *)NULL);
 368         die(_("no info viewer handled the request"));
 369 }
 370
 371 static void get_html_page_path(struct strbuf *page_path, const char *page)
 372 {
 373         struct stat st;
 374         char *to_free = NULL;
 375
 376         if (!html_path)
 377                 html_path = to_free = system_path(GIT_HTML_PATH);
 378
 379         /* Check that we have a git documentation directory. */
 380         if (!strstr(html_path, "://")) {
 381                 if (stat(mkpath("%s/git.html", html_path), &st)
 382                     || !S_ISREG(st.st_mode))
 383                         die("'%s': not a documentation directory.", html_path);
 384         }
 385
 386         strbuf_init(page_path, 0);
 387         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 388         free(to_free);
 389 }
 390
 391 static void open_html(const char *path)
 392 {
 393         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 394 }
 395
 396 static void show_html_page(const char *git_cmd)
 397 {
 398         const char *page = cmd_to_page(git_cmd);
 399         struct strbuf page_path; /* it leaks but we exec bellow */
 400
 401         get_html_page_path(&page_path, page);
 402
 403         open_html(page_path.buf);
 404 }
 405
 406 static const char *check_git_cmd(const char* cmd)
 407 {
 408         char *alias;
 409
 410         if (is_git_command(cmd))
 411                 return cmd;
 412
 413         alias = alias_lookup(cmd);
 414         if (alias) {
 415                 printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
 416                 free(alias);
 417                 exit(0);
 418         }
 419
 420         if (exclude_guides)
 421                 return help_unknown_cmd(cmd);
 422
 423         return cmd;
 424 }
 425
 426 int cmd_help(int argc, const char **argv, const char *prefix)
 427 {
 428         int nongit;
 429         enum help_format parsed_help_format;
 430
 431         argc = parse_options(argc, argv, prefix, builtin_help_options,
 432                         builtin_help_usage, 0);
 433         parsed_help_format = help_format;
 434
 435         if (show_all) {
 436                 git_config(git_help_config, NULL);
 437                 if (verbose) {
 438                         setup_pager();
 439                         list_all_cmds_help();
 440                         return 0;
 441                 }
 442                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 443                 load_command_list("git-", &main_cmds, &other_cmds);
 444                 list_commands(colopts, &main_cmds, &other_cmds);
 445         }
 446
 447         if (show_guides)
 448                 list_common_guides_help();
 449
 450         if (show_all || show_guides) {
 451                 printf("%s\n", _(git_more_info_string));
 452                 /*
 453                 * We're done. Ignore any remaining args
 454                 */
 455                 return 0;
 456         }
 457
 458         if (!argv[0]) {
 459                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 460                 list_common_cmds_help();
 461                 printf("\n%s\n", _(git_more_info_string));
 462                 return 0;
 463         }
 464
 465         setup_git_directory_gently(&nongit);
 466         git_config(git_help_config, NULL);
 467
 468         if (parsed_help_format != HELP_FORMAT_NONE)
 469                 help_format = parsed_help_format;
 470         if (help_format == HELP_FORMAT_NONE)
 471                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 472
 473         argv[0] = check_git_cmd(argv[0]);
 474
 475         switch (help_format) {
 476         case HELP_FORMAT_NONE:
 477         case HELP_FORMAT_MAN:
 478                 show_man_page(argv[0]);
 479                 break;
 480         case HELP_FORMAT_INFO:
 481                 show_info_page(argv[0]);
 482                 break;
 483         case HELP_FORMAT_WEB:
 484                 show_html_page(argv[0]);
 485                 break;
 486         }
 487
 488         return 0;
 489 }