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