builtin/help.c

   1 /*
   2  * builtin-help.c
   3  *
   4  * Builtin help command
   5  */
   6 #include "cache.h"
   7 #include "builtin.h"
   8 #include "exec_cmd.h"
   9 #include "common-cmds.h"
  10 #include "parse-options.h"
  11 #include "run-command.h"
  12 #include "column.h"
  13 #include "help.h"
  14
  15 #ifndef DEFAULT_HELP_FORMAT
  16 #define DEFAULT_HELP_FORMAT "man"
  17 #endif
  18
  19 static struct man_viewer_list {
  20         struct man_viewer_list *next;
  21         char name[FLEX_ARRAY];
  22 } *man_viewer_list;
  23
  24 static struct man_viewer_info_list {
  25         struct man_viewer_info_list *next;
  26         const char *info;
  27         char name[FLEX_ARRAY];
  28 } *man_viewer_info_list;
  29
  30 enum help_format {
  31         HELP_FORMAT_NONE,
  32         HELP_FORMAT_MAN,
  33         HELP_FORMAT_INFO,
  34         HELP_FORMAT_WEB
  35 };
  36
  37 static const char *html_path;
  38
  39 static int show_all = 0;
  40 static unsigned int colopts;
  41 static enum help_format help_format = HELP_FORMAT_NONE;
  42 static struct option builtin_help_options[] = {
  43         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
  44         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  45         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  46                         HELP_FORMAT_WEB),
  47         OPT_SET_INT('i', "info", &help_format, "show info page",
  48                         HELP_FORMAT_INFO),
  49         OPT_END(),
  50 };
  51
  52 static const char * const builtin_help_usage[] = {
  53         "git help [--all] [--man|--web|--info] [command]",
  54         NULL
  55 };
  56
  57 static enum help_format parse_help_format(const char *format)
  58 {
  59         if (!strcmp(format, "man"))
  60                 return HELP_FORMAT_MAN;
  61         if (!strcmp(format, "info"))
  62                 return HELP_FORMAT_INFO;
  63         if (!strcmp(format, "web") || !strcmp(format, "html"))
  64                 return HELP_FORMAT_WEB;
  65         die(_("unrecognized help format '%s'"), format);
  66 }
  67
  68 static const char *get_man_viewer_info(const char *name)
  69 {
  70         struct man_viewer_info_list *viewer;
  71
  72         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  73         {
  74                 if (!strcasecmp(name, viewer->name))
  75                         return viewer->info;
  76         }
  77         return NULL;
  78 }
  79
  80 static int check_emacsclient_version(void)
  81 {
  82         struct strbuf buffer = STRBUF_INIT;
  83         struct child_process ec_process;
  84         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  85         int version;
  86
  87         /* emacsclient prints its version number on stderr */
  88         memset(&ec_process, 0, sizeof(ec_process));
  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 (prefixcmp(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(_("failed to exec '%s': %s"), path, strerror(errno));
 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                         const char *file = strrchr(path, '/');
 146                         if (file && !strcmp(file + 1, "konqueror")) {
 147                                 char *new = xstrdup(path);
 148                                 char *dest = strrchr(new, '/');
 149
 150                                 /* strlen("konqueror") == strlen("kfmclient") */
 151                                 strcpy(dest + 1, "kfmclient");
 152                                 path = new;
 153                         }
 154                         if (file)
 155                                 filename = file;
 156                 } else
 157                         path = "kfmclient";
 158                 strbuf_addf(&man_page, "man:%s(1)", page);
 159                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 160                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 161         }
 162 }
 163
 164 static void exec_man_man(const char *path, const char *page)
 165 {
 166         if (!path)
 167                 path = "man";
 168         execlp(path, "man", page, (char *)NULL);
 169         warning(_("failed to exec '%s': %s"), path, strerror(errno));
 170 }
 171
 172 static void exec_man_cmd(const char *cmd, const char *page)
 173 {
 174         struct strbuf shell_cmd = STRBUF_INIT;
 175         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 176         execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
 177         warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
 178 }
 179
 180 static void add_man_viewer(const char *name)
 181 {
 182         struct man_viewer_list **p = &man_viewer_list;
 183         size_t len = strlen(name);
 184
 185         while (*p)
 186                 p = &((*p)->next);
 187         *p = xcalloc(1, (sizeof(**p) + len + 1));
 188         strncpy((*p)->name, name, len);
 189 }
 190
 191 static int supported_man_viewer(const char *name, size_t len)
 192 {
 193         return (!strncasecmp("man", name, len) ||
 194                 !strncasecmp("woman", name, len) ||
 195                 !strncasecmp("konqueror", name, len));
 196 }
 197
 198 static void do_add_man_viewer_info(const char *name,
 199                                    size_t len,
 200                                    const char *value)
 201 {
 202         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 203
 204         strncpy(new->name, name, len);
 205         new->info = xstrdup(value);
 206         new->next = man_viewer_info_list;
 207         man_viewer_info_list = new;
 208 }
 209
 210 static int add_man_viewer_path(const char *name,
 211                                size_t len,
 212                                const char *value)
 213 {
 214         if (supported_man_viewer(name, len))
 215                 do_add_man_viewer_info(name, len, value);
 216         else
 217                 warning(_("'%s': path for unsupported man viewer.\n"
 218                           "Please consider using 'man.<tool>.cmd' instead."),
 219                         name);
 220
 221         return 0;
 222 }
 223
 224 static int add_man_viewer_cmd(const char *name,
 225                               size_t len,
 226                               const char *value)
 227 {
 228         if (supported_man_viewer(name, len))
 229                 warning(_("'%s': cmd for supported man viewer.\n"
 230                           "Please consider using 'man.<tool>.path' instead."),
 231                         name);
 232         else
 233                 do_add_man_viewer_info(name, len, value);
 234
 235         return 0;
 236 }
 237
 238 static int add_man_viewer_info(const char *var, const char *value)
 239 {
 240         const char *name = var + 4;
 241         const char *subkey = strrchr(name, '.');
 242
 243         if (!subkey)
 244                 return 0;
 245
 246         if (!strcmp(subkey, ".path")) {
 247                 if (!value)
 248                         return config_error_nonbool(var);
 249                 return add_man_viewer_path(name, subkey - name, value);
 250         }
 251         if (!strcmp(subkey, ".cmd")) {
 252                 if (!value)
 253                         return config_error_nonbool(var);
 254                 return add_man_viewer_cmd(name, subkey - name, value);
 255         }
 256
 257         return 0;
 258 }
 259
 260 static int git_help_config(const char *var, const char *value, void *cb)
 261 {
 262         if (!prefixcmp(var, "column."))
 263                 return git_column_config(var, value, "help", &colopts);
 264         if (!strcmp(var, "help.format")) {
 265                 if (!value)
 266                         return config_error_nonbool(var);
 267                 help_format = parse_help_format(value);
 268                 return 0;
 269         }
 270         if (!strcmp(var, "help.htmlpath")) {
 271                 if (!value)
 272                         return config_error_nonbool(var);
 273                 html_path = xstrdup(value);
 274                 return 0;
 275         }
 276         if (!strcmp(var, "man.viewer")) {
 277                 if (!value)
 278                         return config_error_nonbool(var);
 279                 add_man_viewer(value);
 280                 return 0;
 281         }
 282         if (!prefixcmp(var, "man."))
 283                 return add_man_viewer_info(var, value);
 284
 285         return git_default_config(var, value, cb);
 286 }
 287
 288 static struct cmdnames main_cmds, other_cmds;
 289
 290 void list_common_cmds_help(void)
 291 {
 292         int i, longest = 0;
 293
 294         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 295                 if (longest < strlen(common_cmds[i].name))
 296                         longest = strlen(common_cmds[i].name);
 297         }
 298
 299         puts(_("The most commonly used git commands are:"));
 300         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 301                 printf("   %s   ", common_cmds[i].name);
 302                 mput_char(' ', longest - strlen(common_cmds[i].name));
 303                 puts(_(common_cmds[i].help));
 304         }
 305 }
 306
 307 static int is_git_command(const char *s)
 308 {
 309         return is_in_cmdlist(&main_cmds, s) ||
 310                 is_in_cmdlist(&other_cmds, s);
 311 }
 312
 313 static const char *prepend(const char *prefix, const char *cmd)
 314 {
 315         size_t pre_len = strlen(prefix);
 316         size_t cmd_len = strlen(cmd);
 317         char *p = xmalloc(pre_len + cmd_len + 1);
 318         memcpy(p, prefix, pre_len);
 319         strcpy(p + pre_len, cmd);
 320         return p;
 321 }
 322
 323 static const char *cmd_to_page(const char *git_cmd)
 324 {
 325         if (!git_cmd)
 326                 return "git";
 327         else if (!prefixcmp(git_cmd, "git"))
 328                 return git_cmd;
 329         else if (is_git_command(git_cmd))
 330                 return prepend("git-", git_cmd);
 331         else
 332                 return prepend("git", git_cmd);
 333 }
 334
 335 static void setup_man_path(void)
 336 {
 337         struct strbuf new_path = STRBUF_INIT;
 338         const char *old_path = getenv("MANPATH");
 339
 340         /* We should always put ':' after our path. If there is no
 341          * old_path, the ':' at the end will let 'man' to try
 342          * system-wide paths after ours to find the manual page. If
 343          * there is old_path, we need ':' as delimiter. */
 344         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
 345         strbuf_addch(&new_path, ':');
 346         if (old_path)
 347                 strbuf_addstr(&new_path, old_path);
 348
 349         setenv("MANPATH", new_path.buf, 1);
 350
 351         strbuf_release(&new_path);
 352 }
 353
 354 static void exec_viewer(const char *name, const char *page)
 355 {
 356         const char *info = get_man_viewer_info(name);
 357
 358         if (!strcasecmp(name, "man"))
 359                 exec_man_man(info, page);
 360         else if (!strcasecmp(name, "woman"))
 361                 exec_woman_emacs(info, page);
 362         else if (!strcasecmp(name, "konqueror"))
 363                 exec_man_konqueror(info, page);
 364         else if (info)
 365                 exec_man_cmd(info, page);
 366         else
 367                 warning(_("'%s': unknown man viewer."), name);
 368 }
 369
 370 static void show_man_page(const char *git_cmd)
 371 {
 372         struct man_viewer_list *viewer;
 373         const char *page = cmd_to_page(git_cmd);
 374         const char *fallback = getenv("GIT_MAN_VIEWER");
 375
 376         setup_man_path();
 377         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 378         {
 379                 exec_viewer(viewer->name, page); /* will return when unable */
 380         }
 381         if (fallback)
 382                 exec_viewer(fallback, page);
 383         exec_viewer("man", page);
 384         die(_("no man viewer handled the request"));
 385 }
 386
 387 static void show_info_page(const char *git_cmd)
 388 {
 389         const char *page = cmd_to_page(git_cmd);
 390         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 391         execlp("info", "info", "gitman", page, (char *)NULL);
 392         die(_("no info viewer handled the request"));
 393 }
 394
 395 static void get_html_page_path(struct strbuf *page_path, const char *page)
 396 {
 397         struct stat st;
 398         if (!html_path)
 399                 html_path = system_path(GIT_HTML_PATH);
 400
 401         /* Check that we have a git documentation directory. */
 402         if (!strstr(html_path, "://")) {
 403                 if (stat(mkpath("%s/git.html", html_path), &st)
 404                     || !S_ISREG(st.st_mode))
 405                         die("'%s': not a documentation directory.", html_path);
 406         }
 407
 408         strbuf_init(page_path, 0);
 409         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 410 }
 411
 412 /*
 413  * If open_html is not defined in a platform-specific way (see for
 414  * example compat/mingw.h), we use the script web--browse to display
 415  * HTML.
 416  */
 417 #ifndef open_html
 418 static void open_html(const char *path)
 419 {
 420         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 421 }
 422 #endif
 423
 424 static void show_html_page(const char *git_cmd)
 425 {
 426         const char *page = cmd_to_page(git_cmd);
 427         struct strbuf page_path; /* it leaks but we exec bellow */
 428
 429         get_html_page_path(&page_path, page);
 430
 431         open_html(page_path.buf);
 432 }
 433
 434 int cmd_help(int argc, const char **argv, const char *prefix)
 435 {
 436         int nongit;
 437         const char *alias;
 438         enum help_format parsed_help_format;
 439         load_command_list("git-", &main_cmds, &other_cmds);
 440
 441         argc = parse_options(argc, argv, prefix, builtin_help_options,
 442                         builtin_help_usage, 0);
 443         parsed_help_format = help_format;
 444
 445         if (show_all) {
 446                 git_config(git_help_config, NULL);
 447                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 448                 list_commands(colopts, &main_cmds, &other_cmds);
 449                 printf("%s\n", _(git_more_info_string));
 450                 return 0;
 451         }
 452
 453         if (!argv[0]) {
 454                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 455                 list_common_cmds_help();
 456                 printf("\n%s\n", _(git_more_info_string));
 457                 return 0;
 458         }
 459
 460         setup_git_directory_gently(&nongit);
 461         git_config(git_help_config, NULL);
 462
 463         if (parsed_help_format != HELP_FORMAT_NONE)
 464                 help_format = parsed_help_format;
 465         if (help_format == HELP_FORMAT_NONE)
 466                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 467
 468         alias = alias_lookup(argv[0]);
 469         if (alias && !is_git_command(argv[0])) {
 470                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 471                 return 0;
 472         }
 473
 474         switch (help_format) {
 475         case HELP_FORMAT_NONE:
 476         case HELP_FORMAT_MAN:
 477                 show_man_page(argv[0]);
 478                 break;
 479         case HELP_FORMAT_INFO:
 480                 show_info_page(argv[0]);
 481                 break;
 482         case HELP_FORMAT_WEB:
 483                 show_html_page(argv[0]);
 484                 break;
 485         }
 486
 487         return 0;
 488 }