builtin/help.c

   1 /*
   2  * Builtin help command
   3  */
   4 #include "cache.h"
   5 #include "builtin.h"
   6 #include "exec_cmd.h"
   7 #include "parse-options.h"
   8 #include "run-command.h"
   9 #include "column.h"
  10 #include "help.h"
  11
  12 #ifndef DEFAULT_HELP_FORMAT
  13 #define DEFAULT_HELP_FORMAT "man"
  14 #endif
  15
  16 static struct man_viewer_list {
  17         struct man_viewer_list *next;
  18         char name[FLEX_ARRAY];
  19 } *man_viewer_list;
  20
  21 static struct man_viewer_info_list {
  22         struct man_viewer_info_list *next;
  23         const char *info;
  24         char name[FLEX_ARRAY];
  25 } *man_viewer_info_list;
  26
  27 enum help_format {
  28         HELP_FORMAT_NONE,
  29         HELP_FORMAT_MAN,
  30         HELP_FORMAT_INFO,
  31         HELP_FORMAT_WEB
  32 };
  33
  34 static const char *html_path;
  35
  36 static int show_all = 0;
  37 static int show_guides = 0;
  38 static unsigned int colopts;
  39 static enum help_format help_format = HELP_FORMAT_NONE;
  40 static struct option builtin_help_options[] = {
  41         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
  42         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
  43         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  44         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  45                         HELP_FORMAT_WEB),
  46         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  47                         HELP_FORMAT_INFO),
  48         OPT_END(),
  49 };
  50
  51 static const char * const builtin_help_usage[] = {
  52         N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
  53         NULL
  54 };
  55
  56 static enum help_format parse_help_format(const char *format)
  57 {
  58         if (!strcmp(format, "man"))
  59                 return HELP_FORMAT_MAN;
  60         if (!strcmp(format, "info"))
  61                 return HELP_FORMAT_INFO;
  62         if (!strcmp(format, "web") || !strcmp(format, "html"))
  63                 return HELP_FORMAT_WEB;
  64         die(_("unrecognized help format '%s'"), format);
  65 }
  66
  67 static const char *get_man_viewer_info(const char *name)
  68 {
  69         struct man_viewer_info_list *viewer;
  70
  71         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  72         {
  73                 if (!strcasecmp(name, viewer->name))
  74                         return viewer->info;
  75         }
  76         return NULL;
  77 }
  78
  79 static int check_emacsclient_version(void)
  80 {
  81         struct strbuf buffer = STRBUF_INIT;
  82         struct child_process ec_process = CHILD_PROCESS_INIT;
  83         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  84         int version;
  85
  86         /* emacsclient prints its version number on stderr */
  87         ec_process.argv = argv_ec;
  88         ec_process.err = -1;
  89         ec_process.stdout_to_stderr = 1;
  90         if (start_command(&ec_process))
  91                 return error(_("Failed to start emacsclient."));
  92
  93         strbuf_read(&buffer, ec_process.err, 20);
  94         close(ec_process.err);
  95
  96         /*
  97          * Don't bother checking return value, because "emacsclient --version"
  98          * seems to always exits with code 1.
  99          */
 100         finish_command(&ec_process);
 101
 102         if (!starts_with(buffer.buf, "emacsclient")) {
 103                 strbuf_release(&buffer);
 104                 return error(_("Failed to parse emacsclient version."));
 105         }
 106
 107         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 108         version = atoi(buffer.buf);
 109
 110         if (version < 22) {
 111                 strbuf_release(&buffer);
 112                 return error(_("emacsclient version '%d' too old (< 22)."),
 113                         version);
 114         }
 115
 116         strbuf_release(&buffer);
 117         return 0;
 118 }
 119
 120 static void exec_woman_emacs(const char *path, const char *page)
 121 {
 122         if (!check_emacsclient_version()) {
 123                 /* This works only with emacsclient version >= 22. */
 124                 struct strbuf man_page = STRBUF_INIT;
 125
 126                 if (!path)
 127                         path = "emacsclient";
 128                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 129                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 130                 warning_errno(_("failed to exec '%s'"), path);
 131         }
 132 }
 133
 134 static void exec_man_konqueror(const char *path, const char *page)
 135 {
 136         const char *display = getenv("DISPLAY");
 137         if (display && *display) {
 138                 struct strbuf man_page = STRBUF_INIT;
 139                 const char *filename = "kfmclient";
 140
 141                 /* It's simpler to launch konqueror using kfmclient. */
 142                 if (path) {
 143                         size_t len;
 144                         if (strip_suffix(path, "/konqueror", &len))
 145                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 146                         filename = basename((char *)path);
 147                 } else
 148                         path = "kfmclient";
 149                 strbuf_addf(&man_page, "man:%s(1)", page);
 150                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 151                 warning_errno(_("failed to exec '%s'"), path);
 152         }
 153 }
 154
 155 static void exec_man_man(const char *path, const char *page)
 156 {
 157         if (!path)
 158                 path = "man";
 159         execlp(path, "man", page, (char *)NULL);
 160         warning_errno(_("failed to exec '%s'"), path);
 161 }
 162
 163 static void exec_man_cmd(const char *cmd, const char *page)
 164 {
 165         struct strbuf shell_cmd = STRBUF_INIT;
 166         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 167         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 168         warning(_("failed to exec '%s'"), cmd);
 169 }
 170
 171 static void add_man_viewer(const char *name)
 172 {
 173         struct man_viewer_list **p = &man_viewer_list;
 174
 175         while (*p)
 176                 p = &((*p)->next);
 177         FLEX_ALLOC_STR(*p, name, name);
 178 }
 179
 180 static int supported_man_viewer(const char *name, size_t len)
 181 {
 182         return (!strncasecmp("man", name, len) ||
 183                 !strncasecmp("woman", name, len) ||
 184                 !strncasecmp("konqueror", name, len));
 185 }
 186
 187 static void do_add_man_viewer_info(const char *name,
 188                                    size_t len,
 189                                    const char *value)
 190 {
 191         struct man_viewer_info_list *new;
 192         FLEX_ALLOC_MEM(new, name, name, len);
 193         new->info = xstrdup(value);
 194         new->next = man_viewer_info_list;
 195         man_viewer_info_list = new;
 196 }
 197
 198 static int add_man_viewer_path(const char *name,
 199                                size_t len,
 200                                const char *value)
 201 {
 202         if (supported_man_viewer(name, len))
 203                 do_add_man_viewer_info(name, len, value);
 204         else
 205                 warning(_("'%s': path for unsupported man viewer.\n"
 206                           "Please consider using 'man.<tool>.cmd' instead."),
 207                         name);
 208
 209         return 0;
 210 }
 211
 212 static int add_man_viewer_cmd(const char *name,
 213                               size_t len,
 214                               const char *value)
 215 {
 216         if (supported_man_viewer(name, len))
 217                 warning(_("'%s': cmd for supported man viewer.\n"
 218                           "Please consider using 'man.<tool>.path' instead."),
 219                         name);
 220         else
 221                 do_add_man_viewer_info(name, len, value);
 222
 223         return 0;
 224 }
 225
 226 static int add_man_viewer_info(const char *var, const char *value)
 227 {
 228         const char *name, *subkey;
 229         int namelen;
 230
 231         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 232                 return 0;
 233
 234         if (!strcmp(subkey, "path")) {
 235                 if (!value)
 236                         return config_error_nonbool(var);
 237                 return add_man_viewer_path(name, namelen, value);
 238         }
 239         if (!strcmp(subkey, "cmd")) {
 240                 if (!value)
 241                         return config_error_nonbool(var);
 242                 return add_man_viewer_cmd(name, namelen, value);
 243         }
 244
 245         return 0;
 246 }
 247
 248 static int git_help_config(const char *var, const char *value, void *cb)
 249 {
 250         if (starts_with(var, "column."))
 251                 return git_column_config(var, value, "help", &colopts);
 252         if (!strcmp(var, "help.format")) {
 253                 if (!value)
 254                         return config_error_nonbool(var);
 255                 help_format = parse_help_format(value);
 256                 return 0;
 257         }
 258         if (!strcmp(var, "help.htmlpath")) {
 259                 if (!value)
 260                         return config_error_nonbool(var);
 261                 html_path = xstrdup(value);
 262                 return 0;
 263         }
 264         if (!strcmp(var, "man.viewer")) {
 265                 if (!value)
 266                         return config_error_nonbool(var);
 267                 add_man_viewer(value);
 268                 return 0;
 269         }
 270         if (starts_with(var, "man."))
 271                 return add_man_viewer_info(var, value);
 272
 273         return git_default_config(var, value, cb);
 274 }
 275
 276 static struct cmdnames main_cmds, other_cmds;
 277
 278 static int is_git_command(const char *s)
 279 {
 280         if (is_builtin(s))
 281                 return 1;
 282
 283         load_command_list("git-", &main_cmds, &other_cmds);
 284         return is_in_cmdlist(&main_cmds, s) ||
 285                 is_in_cmdlist(&other_cmds, s);
 286 }
 287
 288 static const char *cmd_to_page(const char *git_cmd)
 289 {
 290         if (!git_cmd)
 291                 return "git";
 292         else if (starts_with(git_cmd, "git"))
 293                 return git_cmd;
 294         else if (is_git_command(git_cmd))
 295                 return xstrfmt("git-%s", git_cmd);
 296         else
 297                 return xstrfmt("git%s", git_cmd);
 298 }
 299
 300 static void setup_man_path(void)
 301 {
 302         struct strbuf new_path = STRBUF_INIT;
 303         const char *old_path = getenv("MANPATH");
 304         char *git_man_path = system_path(GIT_MAN_PATH);
 305
 306         /* We should always put ':' after our path. If there is no
 307          * old_path, the ':' at the end will let 'man' to try
 308          * system-wide paths after ours to find the manual page. If
 309          * there is old_path, we need ':' as delimiter. */
 310         strbuf_addstr(&new_path, git_man_path);
 311         strbuf_addch(&new_path, ':');
 312         if (old_path)
 313                 strbuf_addstr(&new_path, old_path);
 314
 315         free(git_man_path);
 316         setenv("MANPATH", new_path.buf, 1);
 317
 318         strbuf_release(&new_path);
 319 }
 320
 321 static void exec_viewer(const char *name, const char *page)
 322 {
 323         const char *info = get_man_viewer_info(name);
 324
 325         if (!strcasecmp(name, "man"))
 326                 exec_man_man(info, page);
 327         else if (!strcasecmp(name, "woman"))
 328                 exec_woman_emacs(info, page);
 329         else if (!strcasecmp(name, "konqueror"))
 330                 exec_man_konqueror(info, page);
 331         else if (info)
 332                 exec_man_cmd(info, page);
 333         else
 334                 warning(_("'%s': unknown man viewer."), name);
 335 }
 336
 337 static void show_man_page(const char *git_cmd)
 338 {
 339         struct man_viewer_list *viewer;
 340         const char *page = cmd_to_page(git_cmd);
 341         const char *fallback = getenv("GIT_MAN_VIEWER");
 342
 343         setup_man_path();
 344         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 345         {
 346                 exec_viewer(viewer->name, page); /* will return when unable */
 347         }
 348         if (fallback)
 349                 exec_viewer(fallback, page);
 350         exec_viewer("man", page);
 351         die(_("no man viewer handled the request"));
 352 }
 353
 354 static void show_info_page(const char *git_cmd)
 355 {
 356         const char *page = cmd_to_page(git_cmd);
 357         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 358         execlp("info", "info", "gitman", page, (char *)NULL);
 359         die(_("no info viewer handled the request"));
 360 }
 361
 362 static void get_html_page_path(struct strbuf *page_path, const char *page)
 363 {
 364         struct stat st;
 365         char *to_free = NULL;
 366
 367         if (!html_path)
 368                 html_path = to_free = system_path(GIT_HTML_PATH);
 369
 370         /* Check that we have a git documentation directory. */
 371         if (!strstr(html_path, "://")) {
 372                 if (stat(mkpath("%s/git.html", html_path), &st)
 373                     || !S_ISREG(st.st_mode))
 374                         die("'%s': not a documentation directory.", html_path);
 375         }
 376
 377         strbuf_init(page_path, 0);
 378         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 379         free(to_free);
 380 }
 381
 382 /*
 383  * If open_html is not defined in a platform-specific way (see for
 384  * example compat/mingw.h), we use the script web--browse to display
 385  * HTML.
 386  */
 387 #ifndef open_html
 388 static void open_html(const char *path)
 389 {
 390         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 391 }
 392 #endif
 393
 394 static void show_html_page(const char *git_cmd)
 395 {
 396         const char *page = cmd_to_page(git_cmd);
 397         struct strbuf page_path; /* it leaks but we exec bellow */
 398
 399         get_html_page_path(&page_path, page);
 400
 401         open_html(page_path.buf);
 402 }
 403
 404 static struct {
 405         const char *name;
 406         const char *help;
 407 } common_guides[] = {
 408         { "attributes", N_("Defining attributes per path") },
 409         { "everyday", N_("Everyday Git With 20 Commands Or So") },
 410         { "glossary", N_("A Git glossary") },
 411         { "ignore", N_("Specifies intentionally untracked files to ignore") },
 412         { "modules", N_("Defining submodule properties") },
 413         { "revisions", N_("Specifying revisions and ranges for Git") },
 414         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
 415         { "workflows", N_("An overview of recommended workflows with Git") },
 416 };
 417
 418 static void list_common_guides_help(void)
 419 {
 420         int i, longest = 0;
 421
 422         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 423                 if (longest < strlen(common_guides[i].name))
 424                         longest = strlen(common_guides[i].name);
 425         }
 426
 427         puts(_("The common Git guides are:\n"));
 428         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 429                 printf("   %s   ", common_guides[i].name);
 430                 mput_char(' ', longest - strlen(common_guides[i].name));
 431                 puts(_(common_guides[i].help));
 432         }
 433         putchar('\n');
 434 }
 435
 436 int cmd_help(int argc, const char **argv, const char *prefix)
 437 {
 438         int nongit;
 439         char *alias;
 440         enum help_format parsed_help_format;
 441
 442         argc = parse_options(argc, argv, prefix, builtin_help_options,
 443                         builtin_help_usage, 0);
 444         parsed_help_format = help_format;
 445
 446         if (show_all) {
 447                 git_config(git_help_config, NULL);
 448                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 449                 load_command_list("git-", &main_cmds, &other_cmds);
 450                 list_commands(colopts, &main_cmds, &other_cmds);
 451         }
 452
 453         if (show_guides)
 454                 list_common_guides_help();
 455
 456         if (show_all || show_guides) {
 457                 printf("%s\n", _(git_more_info_string));
 458                 /*
 459                 * We're done. Ignore any remaining args
 460                 */
 461                 return 0;
 462         }
 463
 464         if (!argv[0]) {
 465                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 466                 list_common_cmds_help();
 467                 printf("\n%s\n", _(git_more_info_string));
 468                 return 0;
 469         }
 470
 471         setup_git_directory_gently(&nongit);
 472         git_config(git_help_config, NULL);
 473
 474         if (parsed_help_format != HELP_FORMAT_NONE)
 475                 help_format = parsed_help_format;
 476         if (help_format == HELP_FORMAT_NONE)
 477                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 478
 479         alias = alias_lookup(argv[0]);
 480         if (alias && !is_git_command(argv[0])) {
 481                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 482                 free(alias);
 483                 return 0;
 484         }
 485
 486         switch (help_format) {
 487         case HELP_FORMAT_NONE:
 488         case HELP_FORMAT_MAN:
 489                 show_man_page(argv[0]);
 490                 break;
 491         case HELP_FORMAT_INFO:
 492                 show_info_page(argv[0]);
 493                 break;
 494         case HELP_FORMAT_WEB:
 495                 show_html_page(argv[0]);
 496                 break;
 497         }
 498
 499         return 0;
 500 }