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
  13 #ifndef DEFAULT_HELP_FORMAT
  14 #define DEFAULT_HELP_FORMAT "man"
  15 #endif
  16
  17 static struct man_viewer_list {
  18         struct man_viewer_list *next;
  19         char name[FLEX_ARRAY];
  20 } *man_viewer_list;
  21
  22 static struct man_viewer_info_list {
  23         struct man_viewer_info_list *next;
  24         const char *info;
  25         char name[FLEX_ARRAY];
  26 } *man_viewer_info_list;
  27
  28 enum help_format {
  29         HELP_FORMAT_NONE,
  30         HELP_FORMAT_MAN,
  31         HELP_FORMAT_INFO,
  32         HELP_FORMAT_WEB
  33 };
  34
  35 static const char *html_path;
  36
  37 static int show_all = 0;
  38 static int show_guides = 0;
  39 static unsigned int colopts;
  40 static enum help_format help_format = HELP_FORMAT_NONE;
  41 static int exclude_guides;
  42 static struct option builtin_help_options[] = {
  43         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
  44         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
  45         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
  46         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  47         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  48                         HELP_FORMAT_WEB),
  49         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  50                         HELP_FORMAT_INFO),
  51         OPT_END(),
  52 };
  53
  54 static const char * const builtin_help_usage[] = {
  55         N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
  56         NULL
  57 };
  58
  59 static enum help_format parse_help_format(const char *format)
  60 {
  61         if (!strcmp(format, "man"))
  62                 return HELP_FORMAT_MAN;
  63         if (!strcmp(format, "info"))
  64                 return HELP_FORMAT_INFO;
  65         if (!strcmp(format, "web") || !strcmp(format, "html"))
  66                 return HELP_FORMAT_WEB;
  67         die(_("unrecognized help format '%s'"), format);
  68 }
  69
  70 static const char *get_man_viewer_info(const char *name)
  71 {
  72         struct man_viewer_info_list *viewer;
  73
  74         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  75         {
  76                 if (!strcasecmp(name, viewer->name))
  77                         return viewer->info;
  78         }
  79         return NULL;
  80 }
  81
  82 static int check_emacsclient_version(void)
  83 {
  84         struct strbuf buffer = STRBUF_INIT;
  85         struct child_process ec_process = CHILD_PROCESS_INIT;
  86         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  87         int version;
  88
  89         /* emacsclient prints its version number on stderr */
  90         ec_process.argv = argv_ec;
  91         ec_process.err = -1;
  92         ec_process.stdout_to_stderr = 1;
  93         if (start_command(&ec_process))
  94                 return error(_("Failed to start emacsclient."));
  95
  96         strbuf_read(&buffer, ec_process.err, 20);
  97         close(ec_process.err);
  98
  99         /*
 100          * Don't bother checking return value, because "emacsclient --version"
 101          * seems to always exits with code 1.
 102          */
 103         finish_command(&ec_process);
 104
 105         if (!starts_with(buffer.buf, "emacsclient")) {
 106                 strbuf_release(&buffer);
 107                 return error(_("Failed to parse emacsclient version."));
 108         }
 109
 110         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 111         version = atoi(buffer.buf);
 112
 113         if (version < 22) {
 114                 strbuf_release(&buffer);
 115                 return error(_("emacsclient version '%d' too old (< 22)."),
 116                         version);
 117         }
 118
 119         strbuf_release(&buffer);
 120         return 0;
 121 }
 122
 123 static void exec_woman_emacs(const char *path, const char *page)
 124 {
 125         if (!check_emacsclient_version()) {
 126                 /* This works only with emacsclient version >= 22. */
 127                 struct strbuf man_page = STRBUF_INIT;
 128
 129                 if (!path)
 130                         path = "emacsclient";
 131                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 132                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 133                 warning_errno(_("failed to exec '%s'"), path);
 134                 strbuf_release(&man_page);
 135         }
 136 }
 137
 138 static void exec_man_konqueror(const char *path, const char *page)
 139 {
 140         const char *display = getenv("DISPLAY");
 141         if (display && *display) {
 142                 struct strbuf man_page = STRBUF_INIT;
 143                 const char *filename = "kfmclient";
 144
 145                 /* It's simpler to launch konqueror using kfmclient. */
 146                 if (path) {
 147                         size_t len;
 148                         if (strip_suffix(path, "/konqueror", &len))
 149                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 150                         filename = basename((char *)path);
 151                 } else
 152                         path = "kfmclient";
 153                 strbuf_addf(&man_page, "man:%s(1)", page);
 154                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 155                 warning_errno(_("failed to exec '%s'"), path);
 156                 strbuf_release(&man_page);
 157         }
 158 }
 159
 160 static void exec_man_man(const char *path, const char *page)
 161 {
 162         if (!path)
 163                 path = "man";
 164         execlp(path, "man", page, (char *)NULL);
 165         warning_errno(_("failed to exec '%s'"), path);
 166 }
 167
 168 static void exec_man_cmd(const char *cmd, const char *page)
 169 {
 170         struct strbuf shell_cmd = STRBUF_INIT;
 171         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 172         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 173         warning(_("failed to exec '%s'"), cmd);
 174         strbuf_release(&shell_cmd);
 175 }
 176
 177 static void add_man_viewer(const char *name)
 178 {
 179         struct man_viewer_list **p = &man_viewer_list;
 180
 181         while (*p)
 182                 p = &((*p)->next);
 183         FLEX_ALLOC_STR(*p, name, name);
 184 }
 185
 186 static int supported_man_viewer(const char *name, size_t len)
 187 {
 188         return (!strncasecmp("man", name, len) ||
 189                 !strncasecmp("woman", name, len) ||
 190                 !strncasecmp("konqueror", name, len));
 191 }
 192
 193 static void do_add_man_viewer_info(const char *name,
 194                                    size_t len,
 195                                    const char *value)
 196 {
 197         struct man_viewer_info_list *new;
 198         FLEX_ALLOC_MEM(new, name, name, len);
 199         new->info = xstrdup(value);
 200         new->next = man_viewer_info_list;
 201         man_viewer_info_list = new;
 202 }
 203
 204 static int add_man_viewer_path(const char *name,
 205                                size_t len,
 206                                const char *value)
 207 {
 208         if (supported_man_viewer(name, len))
 209                 do_add_man_viewer_info(name, len, value);
 210         else
 211                 warning(_("'%s': path for unsupported man viewer.\n"
 212                           "Please consider using 'man.<tool>.cmd' instead."),
 213                         name);
 214
 215         return 0;
 216 }
 217
 218 static int add_man_viewer_cmd(const char *name,
 219                               size_t len,
 220                               const char *value)
 221 {
 222         if (supported_man_viewer(name, len))
 223                 warning(_("'%s': cmd for supported man viewer.\n"
 224                           "Please consider using 'man.<tool>.path' instead."),
 225                         name);
 226         else
 227                 do_add_man_viewer_info(name, len, value);
 228
 229         return 0;
 230 }
 231
 232 static int add_man_viewer_info(const char *var, const char *value)
 233 {
 234         const char *name, *subkey;
 235         int namelen;
 236
 237         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 238                 return 0;
 239
 240         if (!strcmp(subkey, "path")) {
 241                 if (!value)
 242                         return config_error_nonbool(var);
 243                 return add_man_viewer_path(name, namelen, value);
 244         }
 245         if (!strcmp(subkey, "cmd")) {
 246                 if (!value)
 247                         return config_error_nonbool(var);
 248                 return add_man_viewer_cmd(name, namelen, value);
 249         }
 250
 251         return 0;
 252 }
 253
 254 static int git_help_config(const char *var, const char *value, void *cb)
 255 {
 256         if (starts_with(var, "column."))
 257                 return git_column_config(var, value, "help", &colopts);
 258         if (!strcmp(var, "help.format")) {
 259                 if (!value)
 260                         return config_error_nonbool(var);
 261                 help_format = parse_help_format(value);
 262                 return 0;
 263         }
 264         if (!strcmp(var, "help.htmlpath")) {
 265                 if (!value)
 266                         return config_error_nonbool(var);
 267                 html_path = xstrdup(value);
 268                 return 0;
 269         }
 270         if (!strcmp(var, "man.viewer")) {
 271                 if (!value)
 272                         return config_error_nonbool(var);
 273                 add_man_viewer(value);
 274                 return 0;
 275         }
 276         if (starts_with(var, "man."))
 277                 return add_man_viewer_info(var, value);
 278
 279         return git_default_config(var, value, cb);
 280 }
 281
 282 static struct cmdnames main_cmds, other_cmds;
 283
 284 static int is_git_command(const char *s)
 285 {
 286         if (is_builtin(s))
 287                 return 1;
 288
 289         load_command_list("git-", &main_cmds, &other_cmds);
 290         return is_in_cmdlist(&main_cmds, s) ||
 291                 is_in_cmdlist(&other_cmds, s);
 292 }
 293
 294 static const char *cmd_to_page(const char *git_cmd)
 295 {
 296         if (!git_cmd)
 297                 return "git";
 298         else if (starts_with(git_cmd, "git"))
 299                 return git_cmd;
 300         else if (is_git_command(git_cmd))
 301                 return xstrfmt("git-%s", git_cmd);
 302         else
 303                 return xstrfmt("git%s", git_cmd);
 304 }
 305
 306 static void setup_man_path(void)
 307 {
 308         struct strbuf new_path = STRBUF_INIT;
 309         const char *old_path = getenv("MANPATH");
 310         char *git_man_path = system_path(GIT_MAN_PATH);
 311
 312         /* We should always put ':' after our path. If there is no
 313          * old_path, the ':' at the end will let 'man' to try
 314          * system-wide paths after ours to find the manual page. If
 315          * there is old_path, we need ':' as delimiter. */
 316         strbuf_addstr(&new_path, git_man_path);
 317         strbuf_addch(&new_path, ':');
 318         if (old_path)
 319                 strbuf_addstr(&new_path, old_path);
 320
 321         free(git_man_path);
 322         setenv("MANPATH", new_path.buf, 1);
 323
 324         strbuf_release(&new_path);
 325 }
 326
 327 static void exec_viewer(const char *name, const char *page)
 328 {
 329         const char *info = get_man_viewer_info(name);
 330
 331         if (!strcasecmp(name, "man"))
 332                 exec_man_man(info, page);
 333         else if (!strcasecmp(name, "woman"))
 334                 exec_woman_emacs(info, page);
 335         else if (!strcasecmp(name, "konqueror"))
 336                 exec_man_konqueror(info, page);
 337         else if (info)
 338                 exec_man_cmd(info, page);
 339         else
 340                 warning(_("'%s': unknown man viewer."), name);
 341 }
 342
 343 static void show_man_page(const char *git_cmd)
 344 {
 345         struct man_viewer_list *viewer;
 346         const char *page = cmd_to_page(git_cmd);
 347         const char *fallback = getenv("GIT_MAN_VIEWER");
 348
 349         setup_man_path();
 350         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 351         {
 352                 exec_viewer(viewer->name, page); /* will return when unable */
 353         }
 354         if (fallback)
 355                 exec_viewer(fallback, page);
 356         exec_viewer("man", page);
 357         die(_("no man viewer handled the request"));
 358 }
 359
 360 static void show_info_page(const char *git_cmd)
 361 {
 362         const char *page = cmd_to_page(git_cmd);
 363         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 364         execlp("info", "info", "gitman", page, (char *)NULL);
 365         die(_("no info viewer handled the request"));
 366 }
 367
 368 static void get_html_page_path(struct strbuf *page_path, const char *page)
 369 {
 370         struct stat st;
 371         char *to_free = NULL;
 372
 373         if (!html_path)
 374                 html_path = to_free = system_path(GIT_HTML_PATH);
 375
 376         /* Check that we have a git documentation directory. */
 377         if (!strstr(html_path, "://")) {
 378                 if (stat(mkpath("%s/git.html", html_path), &st)
 379                     || !S_ISREG(st.st_mode))
 380                         die("'%s': not a documentation directory.", html_path);
 381         }
 382
 383         strbuf_init(page_path, 0);
 384         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 385         free(to_free);
 386 }
 387
 388 static void open_html(const char *path)
 389 {
 390         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 391 }
 392
 393 static void show_html_page(const char *git_cmd)
 394 {
 395         const char *page = cmd_to_page(git_cmd);
 396         struct strbuf page_path; /* it leaks but we exec bellow */
 397
 398         get_html_page_path(&page_path, page);
 399
 400         open_html(page_path.buf);
 401 }
 402
 403 static struct {
 404         const char *name;
 405         const char *help;
 406 } common_guides[] = {
 407         { "attributes", N_("Defining attributes per path") },
 408         { "everyday", N_("Everyday Git With 20 Commands Or So") },
 409         { "glossary", N_("A Git glossary") },
 410         { "ignore", N_("Specifies intentionally untracked files to ignore") },
 411         { "modules", N_("Defining submodule properties") },
 412         { "revisions", N_("Specifying revisions and ranges for Git") },
 413         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
 414         { "workflows", N_("An overview of recommended workflows with Git") },
 415 };
 416
 417 static void list_common_guides_help(void)
 418 {
 419         int i, longest = 0;
 420
 421         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 422                 if (longest < strlen(common_guides[i].name))
 423                         longest = strlen(common_guides[i].name);
 424         }
 425
 426         puts(_("The common Git guides are:\n"));
 427         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 428                 printf("   %s   ", common_guides[i].name);
 429                 mput_char(' ', longest - strlen(common_guides[i].name));
 430                 puts(_(common_guides[i].help));
 431         }
 432         putchar('\n');
 433 }
 434
 435 static const char *check_git_cmd(const char* cmd)
 436 {
 437         char *alias;
 438
 439         if (is_git_command(cmd))
 440                 return cmd;
 441
 442         alias = alias_lookup(cmd);
 443         if (alias) {
 444                 printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
 445                 free(alias);
 446                 exit(0);
 447         }
 448
 449         if (exclude_guides)
 450                 return help_unknown_cmd(cmd);
 451
 452         return cmd;
 453 }
 454
 455 int cmd_help(int argc, const char **argv, const char *prefix)
 456 {
 457         int nongit;
 458         enum help_format parsed_help_format;
 459
 460         argc = parse_options(argc, argv, prefix, builtin_help_options,
 461                         builtin_help_usage, 0);
 462         parsed_help_format = help_format;
 463
 464         if (show_all) {
 465                 git_config(git_help_config, NULL);
 466                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 467                 load_command_list("git-", &main_cmds, &other_cmds);
 468                 list_commands(colopts, &main_cmds, &other_cmds);
 469         }
 470
 471         if (show_guides)
 472                 list_common_guides_help();
 473
 474         if (show_all || show_guides) {
 475                 printf("%s\n", _(git_more_info_string));
 476                 /*
 477                 * We're done. Ignore any remaining args
 478                 */
 479                 return 0;
 480         }
 481
 482         if (!argv[0]) {
 483                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 484                 list_common_cmds_help();
 485                 printf("\n%s\n", _(git_more_info_string));
 486                 return 0;
 487         }
 488
 489         setup_git_directory_gently(&nongit);
 490         git_config(git_help_config, NULL);
 491
 492         if (parsed_help_format != HELP_FORMAT_NONE)
 493                 help_format = parsed_help_format;
 494         if (help_format == HELP_FORMAT_NONE)
 495                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 496
 497         argv[0] = check_git_cmd(argv[0]);
 498
 499         switch (help_format) {
 500         case HELP_FORMAT_NONE:
 501         case HELP_FORMAT_MAN:
 502                 show_man_page(argv[0]);
 503                 break;
 504         case HELP_FORMAT_INFO:
 505                 show_info_page(argv[0]);
 506                 break;
 507         case HELP_FORMAT_WEB:
 508                 show_html_page(argv[0]);
 509                 break;
 510         }
 511
 512         return 0;
 513 }