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                         const char *file = strrchr(path, '/');
 144                         if (file && !strcmp(file + 1, "konqueror")) {
 145                                 char *new = xstrdup(path);
 146                                 char *dest = strrchr(new, '/');
 147
 148                                 /* strlen("konqueror") == strlen("kfmclient") */
 149                                 strcpy(dest + 1, "kfmclient");
 150                                 path = new;
 151                         }
 152                         if (file)
 153                                 filename = file;
 154                 } else
 155                         path = "kfmclient";
 156                 strbuf_addf(&man_page, "man:%s(1)", page);
 157                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 158                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 159         }
 160 }
 161
 162 static void exec_man_man(const char *path, const char *page)
 163 {
 164         if (!path)
 165                 path = "man";
 166         execlp(path, "man", page, (char *)NULL);
 167         warning(_("failed to exec '%s': %s"), path, strerror(errno));
 168 }
 169
 170 static void exec_man_cmd(const char *cmd, const char *page)
 171 {
 172         struct strbuf shell_cmd = STRBUF_INIT;
 173         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 174         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 175         warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
 176 }
 177
 178 static void add_man_viewer(const char *name)
 179 {
 180         struct man_viewer_list **p = &man_viewer_list;
 181         size_t len = strlen(name);
 182
 183         while (*p)
 184                 p = &((*p)->next);
 185         *p = xcalloc(1, (sizeof(**p) + len + 1));
 186         strncpy((*p)->name, name, len);
 187 }
 188
 189 static int supported_man_viewer(const char *name, size_t len)
 190 {
 191         return (!strncasecmp("man", name, len) ||
 192                 !strncasecmp("woman", name, len) ||
 193                 !strncasecmp("konqueror", name, len));
 194 }
 195
 196 static void do_add_man_viewer_info(const char *name,
 197                                    size_t len,
 198                                    const char *value)
 199 {
 200         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 201
 202         strncpy(new->name, name, len);
 203         new->info = xstrdup(value);
 204         new->next = man_viewer_info_list;
 205         man_viewer_info_list = new;
 206 }
 207
 208 static int add_man_viewer_path(const char *name,
 209                                size_t len,
 210                                const char *value)
 211 {
 212         if (supported_man_viewer(name, len))
 213                 do_add_man_viewer_info(name, len, value);
 214         else
 215                 warning(_("'%s': path for unsupported man viewer.\n"
 216                           "Please consider using 'man.<tool>.cmd' instead."),
 217                         name);
 218
 219         return 0;
 220 }
 221
 222 static int add_man_viewer_cmd(const char *name,
 223                               size_t len,
 224                               const char *value)
 225 {
 226         if (supported_man_viewer(name, len))
 227                 warning(_("'%s': cmd for supported man viewer.\n"
 228                           "Please consider using 'man.<tool>.path' instead."),
 229                         name);
 230         else
 231                 do_add_man_viewer_info(name, len, value);
 232
 233         return 0;
 234 }
 235
 236 static int add_man_viewer_info(const char *var, const char *value)
 237 {
 238         const char *name, *subkey;
 239         int namelen;
 240
 241         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 242                 return 0;
 243
 244         if (!strcmp(subkey, "path")) {
 245                 if (!value)
 246                         return config_error_nonbool(var);
 247                 return add_man_viewer_path(name, namelen, value);
 248         }
 249         if (!strcmp(subkey, "cmd")) {
 250                 if (!value)
 251                         return config_error_nonbool(var);
 252                 return add_man_viewer_cmd(name, namelen, value);
 253         }
 254
 255         return 0;
 256 }
 257
 258 static int git_help_config(const char *var, const char *value, void *cb)
 259 {
 260         if (starts_with(var, "column."))
 261                 return git_column_config(var, value, "help", &colopts);
 262         if (!strcmp(var, "help.format")) {
 263                 if (!value)
 264                         return config_error_nonbool(var);
 265                 help_format = parse_help_format(value);
 266                 return 0;
 267         }
 268         if (!strcmp(var, "help.htmlpath")) {
 269                 if (!value)
 270                         return config_error_nonbool(var);
 271                 html_path = xstrdup(value);
 272                 return 0;
 273         }
 274         if (!strcmp(var, "man.viewer")) {
 275                 if (!value)
 276                         return config_error_nonbool(var);
 277                 add_man_viewer(value);
 278                 return 0;
 279         }
 280         if (starts_with(var, "man."))
 281                 return add_man_viewer_info(var, value);
 282
 283         return git_default_config(var, value, cb);
 284 }
 285
 286 static struct cmdnames main_cmds, other_cmds;
 287
 288 static int is_git_command(const char *s)
 289 {
 290         if (is_builtin(s))
 291                 return 1;
 292
 293         load_command_list("git-", &main_cmds, &other_cmds);
 294         return is_in_cmdlist(&main_cmds, s) ||
 295                 is_in_cmdlist(&other_cmds, s);
 296 }
 297
 298 static const char *prepend(const char *prefix, const char *cmd)
 299 {
 300         size_t pre_len = strlen(prefix);
 301         size_t cmd_len = strlen(cmd);
 302         char *p = xmalloc(pre_len + cmd_len + 1);
 303         memcpy(p, prefix, pre_len);
 304         strcpy(p + pre_len, cmd);
 305         return p;
 306 }
 307
 308 static const char *cmd_to_page(const char *git_cmd)
 309 {
 310         if (!git_cmd)
 311                 return "git";
 312         else if (starts_with(git_cmd, "git"))
 313                 return git_cmd;
 314         else if (is_git_command(git_cmd))
 315                 return prepend("git-", git_cmd);
 316         else
 317                 return prepend("git", git_cmd);
 318 }
 319
 320 static void setup_man_path(void)
 321 {
 322         struct strbuf new_path = STRBUF_INIT;
 323         const char *old_path = getenv("MANPATH");
 324         char *git_man_path = system_path(GIT_MAN_PATH);
 325
 326         /* We should always put ':' after our path. If there is no
 327          * old_path, the ':' at the end will let 'man' to try
 328          * system-wide paths after ours to find the manual page. If
 329          * there is old_path, we need ':' as delimiter. */
 330         strbuf_addstr(&new_path, git_man_path);
 331         strbuf_addch(&new_path, ':');
 332         if (old_path)
 333                 strbuf_addstr(&new_path, old_path);
 334
 335         free(git_man_path);
 336         setenv("MANPATH", new_path.buf, 1);
 337
 338         strbuf_release(&new_path);
 339 }
 340
 341 static void exec_viewer(const char *name, const char *page)
 342 {
 343         const char *info = get_man_viewer_info(name);
 344
 345         if (!strcasecmp(name, "man"))
 346                 exec_man_man(info, page);
 347         else if (!strcasecmp(name, "woman"))
 348                 exec_woman_emacs(info, page);
 349         else if (!strcasecmp(name, "konqueror"))
 350                 exec_man_konqueror(info, page);
 351         else if (info)
 352                 exec_man_cmd(info, page);
 353         else
 354                 warning(_("'%s': unknown man viewer."), name);
 355 }
 356
 357 static void show_man_page(const char *git_cmd)
 358 {
 359         struct man_viewer_list *viewer;
 360         const char *page = cmd_to_page(git_cmd);
 361         const char *fallback = getenv("GIT_MAN_VIEWER");
 362
 363         setup_man_path();
 364         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 365         {
 366                 exec_viewer(viewer->name, page); /* will return when unable */
 367         }
 368         if (fallback)
 369                 exec_viewer(fallback, page);
 370         exec_viewer("man", page);
 371         die(_("no man viewer handled the request"));
 372 }
 373
 374 static void show_info_page(const char *git_cmd)
 375 {
 376         const char *page = cmd_to_page(git_cmd);
 377         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 378         execlp("info", "info", "gitman", page, (char *)NULL);
 379         die(_("no info viewer handled the request"));
 380 }
 381
 382 static void get_html_page_path(struct strbuf *page_path, const char *page)
 383 {
 384         struct stat st;
 385         char *to_free = NULL;
 386
 387         if (!html_path)
 388                 html_path = to_free = system_path(GIT_HTML_PATH);
 389
 390         /* Check that we have a git documentation directory. */
 391         if (!strstr(html_path, "://")) {
 392                 if (stat(mkpath("%s/git.html", html_path), &st)
 393                     || !S_ISREG(st.st_mode))
 394                         die("'%s': not a documentation directory.", html_path);
 395         }
 396
 397         strbuf_init(page_path, 0);
 398         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 399         free(to_free);
 400 }
 401
 402 /*
 403  * If open_html is not defined in a platform-specific way (see for
 404  * example compat/mingw.h), we use the script web--browse to display
 405  * HTML.
 406  */
 407 #ifndef open_html
 408 static void open_html(const char *path)
 409 {
 410         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 411 }
 412 #endif
 413
 414 static void show_html_page(const char *git_cmd)
 415 {
 416         const char *page = cmd_to_page(git_cmd);
 417         struct strbuf page_path; /* it leaks but we exec bellow */
 418
 419         get_html_page_path(&page_path, page);
 420
 421         open_html(page_path.buf);
 422 }
 423
 424 static struct {
 425         const char *name;
 426         const char *help;
 427 } common_guides[] = {
 428         { "attributes", N_("Defining attributes per path") },
 429         { "everyday", N_("Everyday Git With 20 Commands Or So") },
 430         { "glossary", N_("A Git glossary") },
 431         { "ignore", N_("Specifies intentionally untracked files to ignore") },
 432         { "modules", N_("Defining submodule properties") },
 433         { "revisions", N_("Specifying revisions and ranges for Git") },
 434         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
 435         { "workflows", N_("An overview of recommended workflows with Git") },
 436 };
 437
 438 static void list_common_guides_help(void)
 439 {
 440         int i, longest = 0;
 441
 442         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 443                 if (longest < strlen(common_guides[i].name))
 444                         longest = strlen(common_guides[i].name);
 445         }
 446
 447         puts(_("The common Git guides are:\n"));
 448         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 449                 printf("   %s   ", common_guides[i].name);
 450                 mput_char(' ', longest - strlen(common_guides[i].name));
 451                 puts(_(common_guides[i].help));
 452         }
 453         putchar('\n');
 454 }
 455
 456 int cmd_help(int argc, const char **argv, const char *prefix)
 457 {
 458         int nongit;
 459         char *alias;
 460         enum help_format parsed_help_format;
 461
 462         argc = parse_options(argc, argv, prefix, builtin_help_options,
 463                         builtin_help_usage, 0);
 464         parsed_help_format = help_format;
 465
 466         if (show_all) {
 467                 git_config(git_help_config, NULL);
 468                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 469                 load_command_list("git-", &main_cmds, &other_cmds);
 470                 list_commands(colopts, &main_cmds, &other_cmds);
 471         }
 472
 473         if (show_guides)
 474                 list_common_guides_help();
 475
 476         if (show_all || show_guides) {
 477                 printf("%s\n", _(git_more_info_string));
 478                 /*
 479                 * We're done. Ignore any remaining args
 480                 */
 481                 return 0;
 482         }
 483
 484         if (!argv[0]) {
 485                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 486                 list_common_cmds_help();
 487                 printf("\n%s\n", _(git_more_info_string));
 488                 return 0;
 489         }
 490
 491         setup_git_directory_gently(&nongit);
 492         git_config(git_help_config, NULL);
 493
 494         if (parsed_help_format != HELP_FORMAT_NONE)
 495                 help_format = parsed_help_format;
 496         if (help_format == HELP_FORMAT_NONE)
 497                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 498
 499         alias = alias_lookup(argv[0]);
 500         if (alias && !is_git_command(argv[0])) {
 501                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 502                 free(alias);
 503                 return 0;
 504         }
 505
 506         switch (help_format) {
 507         case HELP_FORMAT_NONE:
 508         case HELP_FORMAT_MAN:
 509                 show_man_page(argv[0]);
 510                 break;
 511         case HELP_FORMAT_INFO:
 512                 show_info_page(argv[0]);
 513                 break;
 514         case HELP_FORMAT_WEB:
 515                 show_html_page(argv[0]);
 516                 break;
 517         }
 518
 519         return 0;
 520 }