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(_("failed to exec '%s': %s"), path, strerror(errno));
 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(_("failed to exec '%s': %s"), path, strerror(errno));
 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(_("failed to exec '%s': %s"), path, strerror(errno));
 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': %s"), cmd, strerror(errno));
 169 }
 170
 171 static void add_man_viewer(const char *name)
 172 {
 173         struct man_viewer_list **p = &man_viewer_list;
 174         size_t len = strlen(name);
 175
 176         while (*p)
 177                 p = &((*p)->next);
 178         *p = xcalloc(1, (sizeof(**p) + len + 1));
 179         memcpy((*p)->name, name, len); /* NUL-terminated by xcalloc */
 180 }
 181
 182 static int supported_man_viewer(const char *name, size_t len)
 183 {
 184         return (!strncasecmp("man", name, len) ||
 185                 !strncasecmp("woman", name, len) ||
 186                 !strncasecmp("konqueror", name, len));
 187 }
 188
 189 static void do_add_man_viewer_info(const char *name,
 190                                    size_t len,
 191                                    const char *value)
 192 {
 193         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 194
 195         memcpy(new->name, name, len); /* NUL-terminated by xcalloc */
 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 /*
 386  * If open_html is not defined in a platform-specific way (see for
 387  * example compat/mingw.h), we use the script web--browse to display
 388  * HTML.
 389  */
 390 #ifndef open_html
 391 static void open_html(const char *path)
 392 {
 393         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 394 }
 395 #endif
 396
 397 static void show_html_page(const char *git_cmd)
 398 {
 399         const char *page = cmd_to_page(git_cmd);
 400         struct strbuf page_path; /* it leaks but we exec bellow */
 401
 402         get_html_page_path(&page_path, page);
 403
 404         open_html(page_path.buf);
 405 }
 406
 407 static struct {
 408         const char *name;
 409         const char *help;
 410 } common_guides[] = {
 411         { "attributes", N_("Defining attributes per path") },
 412         { "everyday", N_("Everyday Git With 20 Commands Or So") },
 413         { "glossary", N_("A Git glossary") },
 414         { "ignore", N_("Specifies intentionally untracked files to ignore") },
 415         { "modules", N_("Defining submodule properties") },
 416         { "revisions", N_("Specifying revisions and ranges for Git") },
 417         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
 418         { "workflows", N_("An overview of recommended workflows with Git") },
 419 };
 420
 421 static void list_common_guides_help(void)
 422 {
 423         int i, longest = 0;
 424
 425         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 426                 if (longest < strlen(common_guides[i].name))
 427                         longest = strlen(common_guides[i].name);
 428         }
 429
 430         puts(_("The common Git guides are:\n"));
 431         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 432                 printf("   %s   ", common_guides[i].name);
 433                 mput_char(' ', longest - strlen(common_guides[i].name));
 434                 puts(_(common_guides[i].help));
 435         }
 436         putchar('\n');
 437 }
 438
 439 int cmd_help(int argc, const char **argv, const char *prefix)
 440 {
 441         int nongit;
 442         char *alias;
 443         enum help_format parsed_help_format;
 444
 445         argc = parse_options(argc, argv, prefix, builtin_help_options,
 446                         builtin_help_usage, 0);
 447         parsed_help_format = help_format;
 448
 449         if (show_all) {
 450                 git_config(git_help_config, NULL);
 451                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 452                 load_command_list("git-", &main_cmds, &other_cmds);
 453                 list_commands(colopts, &main_cmds, &other_cmds);
 454         }
 455
 456         if (show_guides)
 457                 list_common_guides_help();
 458
 459         if (show_all || show_guides) {
 460                 printf("%s\n", _(git_more_info_string));
 461                 /*
 462                 * We're done. Ignore any remaining args
 463                 */
 464                 return 0;
 465         }
 466
 467         if (!argv[0]) {
 468                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 469                 list_common_cmds_help();
 470                 printf("\n%s\n", _(git_more_info_string));
 471                 return 0;
 472         }
 473
 474         setup_git_directory_gently(&nongit);
 475         git_config(git_help_config, NULL);
 476
 477         if (parsed_help_format != HELP_FORMAT_NONE)
 478                 help_format = parsed_help_format;
 479         if (help_format == HELP_FORMAT_NONE)
 480                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 481
 482         alias = alias_lookup(argv[0]);
 483         if (alias && !is_git_command(argv[0])) {
 484                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 485                 free(alias);
 486                 return 0;
 487         }
 488
 489         switch (help_format) {
 490         case HELP_FORMAT_NONE:
 491         case HELP_FORMAT_MAN:
 492                 show_man_page(argv[0]);
 493                 break;
 494         case HELP_FORMAT_INFO:
 495                 show_info_page(argv[0]);
 496                 break;
 497         case HELP_FORMAT_WEB:
 498                 show_html_page(argv[0]);
 499                 break;
 500         }
 501
 502         return 0;
 503 }