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