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         }
 135 }
 136
 137 static void exec_man_konqueror(const char *path, const char *page)
 138 {
 139         const char *display = getenv("DISPLAY");
 140         if (display && *display) {
 141                 struct strbuf man_page = STRBUF_INIT;
 142                 const char *filename = "kfmclient";
 143
 144                 /* It's simpler to launch konqueror using kfmclient. */
 145                 if (path) {
 146                         size_t len;
 147                         if (strip_suffix(path, "/konqueror", &len))
 148                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 149                         filename = basename((char *)path);
 150                 } else
 151                         path = "kfmclient";
 152                 strbuf_addf(&man_page, "man:%s(1)", page);
 153                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 154                 warning_errno(_("failed to exec '%s'"), path);
 155         }
 156 }
 157
 158 static void exec_man_man(const char *path, const char *page)
 159 {
 160         if (!path)
 161                 path = "man";
 162         execlp(path, "man", page, (char *)NULL);
 163         warning_errno(_("failed to exec '%s'"), path);
 164 }
 165
 166 static void exec_man_cmd(const char *cmd, const char *page)
 167 {
 168         struct strbuf shell_cmd = STRBUF_INIT;
 169         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 170         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 171         warning(_("failed to exec '%s'"), cmd);
 172 }
 173
 174 static void add_man_viewer(const char *name)
 175 {
 176         struct man_viewer_list **p = &man_viewer_list;
 177
 178         while (*p)
 179                 p = &((*p)->next);
 180         FLEX_ALLOC_STR(*p, name, name);
 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;
 195         FLEX_ALLOC_MEM(new, name, name, len);
 196         new->info = xstrdup(value);
 197         new->next = man_viewer_info_list;
 198         man_viewer_info_list = new;
 199 }
 200
 201 static int add_man_viewer_path(const char *name,
 202                                size_t len,
 203                                const char *value)
 204 {
 205         if (supported_man_viewer(name, len))
 206                 do_add_man_viewer_info(name, len, value);
 207         else
 208                 warning(_("'%s': path for unsupported man viewer.\n"
 209                           "Please consider using 'man.<tool>.cmd' instead."),
 210                         name);
 211
 212         return 0;
 213 }
 214
 215 static int add_man_viewer_cmd(const char *name,
 216                               size_t len,
 217                               const char *value)
 218 {
 219         if (supported_man_viewer(name, len))
 220                 warning(_("'%s': cmd for supported man viewer.\n"
 221                           "Please consider using 'man.<tool>.path' instead."),
 222                         name);
 223         else
 224                 do_add_man_viewer_info(name, len, value);
 225
 226         return 0;
 227 }
 228
 229 static int add_man_viewer_info(const char *var, const char *value)
 230 {
 231         const char *name, *subkey;
 232         int namelen;
 233
 234         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 235                 return 0;
 236
 237         if (!strcmp(subkey, "path")) {
 238                 if (!value)
 239                         return config_error_nonbool(var);
 240                 return add_man_viewer_path(name, namelen, value);
 241         }
 242         if (!strcmp(subkey, "cmd")) {
 243                 if (!value)
 244                         return config_error_nonbool(var);
 245                 return add_man_viewer_cmd(name, namelen, value);
 246         }
 247
 248         return 0;
 249 }
 250
 251 static int git_help_config(const char *var, const char *value, void *cb)
 252 {
 253         if (starts_with(var, "column."))
 254                 return git_column_config(var, value, "help", &colopts);
 255         if (!strcmp(var, "help.format")) {
 256                 if (!value)
 257                         return config_error_nonbool(var);
 258                 help_format = parse_help_format(value);
 259                 return 0;
 260         }
 261         if (!strcmp(var, "help.htmlpath")) {
 262                 if (!value)
 263                         return config_error_nonbool(var);
 264                 html_path = xstrdup(value);
 265                 return 0;
 266         }
 267         if (!strcmp(var, "man.viewer")) {
 268                 if (!value)
 269                         return config_error_nonbool(var);
 270                 add_man_viewer(value);
 271                 return 0;
 272         }
 273         if (starts_with(var, "man."))
 274                 return add_man_viewer_info(var, value);
 275
 276         return git_default_config(var, value, cb);
 277 }
 278
 279 static struct cmdnames main_cmds, other_cmds;
 280
 281 static int is_git_command(const char *s)
 282 {
 283         if (is_builtin(s))
 284                 return 1;
 285
 286         load_command_list("git-", &main_cmds, &other_cmds);
 287         return is_in_cmdlist(&main_cmds, s) ||
 288                 is_in_cmdlist(&other_cmds, s);
 289 }
 290
 291 static const char *cmd_to_page(const char *git_cmd)
 292 {
 293         if (!git_cmd)
 294                 return "git";
 295         else if (starts_with(git_cmd, "git"))
 296                 return git_cmd;
 297         else if (is_git_command(git_cmd))
 298                 return xstrfmt("git-%s", git_cmd);
 299         else
 300                 return xstrfmt("git%s", git_cmd);
 301 }
 302
 303 static void setup_man_path(void)
 304 {
 305         struct strbuf new_path = STRBUF_INIT;
 306         const char *old_path = getenv("MANPATH");
 307         char *git_man_path = system_path(GIT_MAN_PATH);
 308
 309         /* We should always put ':' after our path. If there is no
 310          * old_path, the ':' at the end will let 'man' to try
 311          * system-wide paths after ours to find the manual page. If
 312          * there is old_path, we need ':' as delimiter. */
 313         strbuf_addstr(&new_path, git_man_path);
 314         strbuf_addch(&new_path, ':');
 315         if (old_path)
 316                 strbuf_addstr(&new_path, old_path);
 317
 318         free(git_man_path);
 319         setenv("MANPATH", new_path.buf, 1);
 320
 321         strbuf_release(&new_path);
 322 }
 323
 324 static void exec_viewer(const char *name, const char *page)
 325 {
 326         const char *info = get_man_viewer_info(name);
 327
 328         if (!strcasecmp(name, "man"))
 329                 exec_man_man(info, page);
 330         else if (!strcasecmp(name, "woman"))
 331                 exec_woman_emacs(info, page);
 332         else if (!strcasecmp(name, "konqueror"))
 333                 exec_man_konqueror(info, page);
 334         else if (info)
 335                 exec_man_cmd(info, page);
 336         else
 337                 warning(_("'%s': unknown man viewer."), name);
 338 }
 339
 340 static void show_man_page(const char *git_cmd)
 341 {
 342         struct man_viewer_list *viewer;
 343         const char *page = cmd_to_page(git_cmd);
 344         const char *fallback = getenv("GIT_MAN_VIEWER");
 345
 346         setup_man_path();
 347         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 348         {
 349                 exec_viewer(viewer->name, page); /* will return when unable */
 350         }
 351         if (fallback)
 352                 exec_viewer(fallback, page);
 353         exec_viewer("man", page);
 354         die(_("no man viewer handled the request"));
 355 }
 356
 357 static void show_info_page(const char *git_cmd)
 358 {
 359         const char *page = cmd_to_page(git_cmd);
 360         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 361         execlp("info", "info", "gitman", page, (char *)NULL);
 362         die(_("no info viewer handled the request"));
 363 }
 364
 365 static void get_html_page_path(struct strbuf *page_path, const char *page)
 366 {
 367         struct stat st;
 368         char *to_free = NULL;
 369
 370         if (!html_path)
 371                 html_path = to_free = system_path(GIT_HTML_PATH);
 372
 373         /* Check that we have a git documentation directory. */
 374         if (!strstr(html_path, "://")) {
 375                 if (stat(mkpath("%s/git.html", html_path), &st)
 376                     || !S_ISREG(st.st_mode))
 377                         die("'%s': not a documentation directory.", html_path);
 378         }
 379
 380         strbuf_init(page_path, 0);
 381         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 382         free(to_free);
 383 }
 384
 385 static void open_html(const char *path)
 386 {
 387         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 388 }
 389
 390 static void show_html_page(const char *git_cmd)
 391 {
 392         const char *page = cmd_to_page(git_cmd);
 393         struct strbuf page_path; /* it leaks but we exec bellow */
 394
 395         get_html_page_path(&page_path, page);
 396
 397         open_html(page_path.buf);
 398 }
 399
 400 static struct {
 401         const char *name;
 402         const char *help;
 403 } common_guides[] = {
 404         { "attributes", N_("Defining attributes per path") },
 405         { "everyday", N_("Everyday Git With 20 Commands Or So") },
 406         { "glossary", N_("A Git glossary") },
 407         { "ignore", N_("Specifies intentionally untracked files to ignore") },
 408         { "modules", N_("Defining submodule properties") },
 409         { "revisions", N_("Specifying revisions and ranges for Git") },
 410         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
 411         { "workflows", N_("An overview of recommended workflows with Git") },
 412 };
 413
 414 static void list_common_guides_help(void)
 415 {
 416         int i, longest = 0;
 417
 418         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 419                 if (longest < strlen(common_guides[i].name))
 420                         longest = strlen(common_guides[i].name);
 421         }
 422
 423         puts(_("The common Git guides are:\n"));
 424         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 425                 printf("   %s   ", common_guides[i].name);
 426                 mput_char(' ', longest - strlen(common_guides[i].name));
 427                 puts(_(common_guides[i].help));
 428         }
 429         putchar('\n');
 430 }
 431
 432 static const char *check_git_cmd(const char* cmd)
 433 {
 434         char *alias;
 435
 436         if (is_git_command(cmd))
 437                 return cmd;
 438
 439         alias = alias_lookup(cmd);
 440         if (alias) {
 441                 printf_ln(_("`git %s' is aliased to `%s'"), cmd, alias);
 442                 free(alias);
 443                 exit(0);
 444         }
 445
 446         if (exclude_guides)
 447                 return help_unknown_cmd(cmd);
 448
 449         return cmd;
 450 }
 451
 452 int cmd_help(int argc, const char **argv, const char *prefix)
 453 {
 454         int nongit;
 455         enum help_format parsed_help_format;
 456
 457         argc = parse_options(argc, argv, prefix, builtin_help_options,
 458                         builtin_help_usage, 0);
 459         parsed_help_format = help_format;
 460
 461         if (show_all) {
 462                 git_config(git_help_config, NULL);
 463                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 464                 load_command_list("git-", &main_cmds, &other_cmds);
 465                 list_commands(colopts, &main_cmds, &other_cmds);
 466         }
 467
 468         if (show_guides)
 469                 list_common_guides_help();
 470
 471         if (show_all || show_guides) {
 472                 printf("%s\n", _(git_more_info_string));
 473                 /*
 474                 * We're done. Ignore any remaining args
 475                 */
 476                 return 0;
 477         }
 478
 479         if (!argv[0]) {
 480                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 481                 list_common_cmds_help();
 482                 printf("\n%s\n", _(git_more_info_string));
 483                 return 0;
 484         }
 485
 486         setup_git_directory_gently(&nongit);
 487         git_config(git_help_config, NULL);
 488
 489         if (parsed_help_format != HELP_FORMAT_NONE)
 490                 help_format = parsed_help_format;
 491         if (help_format == HELP_FORMAT_NONE)
 492                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 493
 494         argv[0] = check_git_cmd(argv[0]);
 495
 496         switch (help_format) {
 497         case HELP_FORMAT_NONE:
 498         case HELP_FORMAT_MAN:
 499                 show_man_page(argv[0]);
 500                 break;
 501         case HELP_FORMAT_INFO:
 502                 show_info_page(argv[0]);
 503                 break;
 504         case HELP_FORMAT_WEB:
 505                 show_html_page(argv[0]);
 506                 break;
 507         }
 508
 509         return 0;
 510 }