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 unsigned int colopts;
  38 static enum help_format help_format = HELP_FORMAT_NONE;
  39 static struct option builtin_help_options[] = {
  40         OPT_BOOLEAN('a', "all", &show_all, N_("print all available commands")),
  41         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  42         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  43                         HELP_FORMAT_WEB),
  44         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  45                         HELP_FORMAT_INFO),
  46         OPT_END(),
  47 };
  48
  49 static const char * const builtin_help_usage[] = {
  50         N_("git help [--all] [--man|--web|--info] [command]"),
  51         NULL
  52 };
  53
  54 static enum help_format parse_help_format(const char *format)
  55 {
  56         if (!strcmp(format, "man"))
  57                 return HELP_FORMAT_MAN;
  58         if (!strcmp(format, "info"))
  59                 return HELP_FORMAT_INFO;
  60         if (!strcmp(format, "web") || !strcmp(format, "html"))
  61                 return HELP_FORMAT_WEB;
  62         die(_("unrecognized help format '%s'"), format);
  63 }
  64
  65 static const char *get_man_viewer_info(const char *name)
  66 {
  67         struct man_viewer_info_list *viewer;
  68
  69         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  70         {
  71                 if (!strcasecmp(name, viewer->name))
  72                         return viewer->info;
  73         }
  74         return NULL;
  75 }
  76
  77 static int check_emacsclient_version(void)
  78 {
  79         struct strbuf buffer = STRBUF_INIT;
  80         struct child_process ec_process;
  81         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  82         int version;
  83
  84         /* emacsclient prints its version number on stderr */
  85         memset(&ec_process, 0, sizeof(ec_process));
  86         ec_process.argv = argv_ec;
  87         ec_process.err = -1;
  88         ec_process.stdout_to_stderr = 1;
  89         if (start_command(&ec_process))
  90                 return error(_("Failed to start emacsclient."));
  91
  92         strbuf_read(&buffer, ec_process.err, 20);
  93         close(ec_process.err);
  94
  95         /*
  96          * Don't bother checking return value, because "emacsclient --version"
  97          * seems to always exits with code 1.
  98          */
  99         finish_command(&ec_process);
 100
 101         if (prefixcmp(buffer.buf, "emacsclient")) {
 102                 strbuf_release(&buffer);
 103                 return error(_("Failed to parse emacsclient version."));
 104         }
 105
 106         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 107         version = atoi(buffer.buf);
 108
 109         if (version < 22) {
 110                 strbuf_release(&buffer);
 111                 return error(_("emacsclient version '%d' too old (< 22)."),
 112                         version);
 113         }
 114
 115         strbuf_release(&buffer);
 116         return 0;
 117 }
 118
 119 static void exec_woman_emacs(const char *path, const char *page)
 120 {
 121         if (!check_emacsclient_version()) {
 122                 /* This works only with emacsclient version >= 22. */
 123                 struct strbuf man_page = STRBUF_INIT;
 124
 125                 if (!path)
 126                         path = "emacsclient";
 127                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 128                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 129                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 130         }
 131 }
 132
 133 static void exec_man_konqueror(const char *path, const char *page)
 134 {
 135         const char *display = getenv("DISPLAY");
 136         if (display && *display) {
 137                 struct strbuf man_page = STRBUF_INIT;
 138                 const char *filename = "kfmclient";
 139
 140                 /* It's simpler to launch konqueror using kfmclient. */
 141                 if (path) {
 142                         const char *file = strrchr(path, '/');
 143                         if (file && !strcmp(file + 1, "konqueror")) {
 144                                 char *new = xstrdup(path);
 145                                 char *dest = strrchr(new, '/');
 146
 147                                 /* strlen("konqueror") == strlen("kfmclient") */
 148                                 strcpy(dest + 1, "kfmclient");
 149                                 path = new;
 150                         }
 151                         if (file)
 152                                 filename = file;
 153                 } else
 154                         path = "kfmclient";
 155                 strbuf_addf(&man_page, "man:%s(1)", page);
 156                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 157                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 158         }
 159 }
 160
 161 static void exec_man_man(const char *path, const char *page)
 162 {
 163         if (!path)
 164                 path = "man";
 165         execlp(path, "man", page, (char *)NULL);
 166         warning(_("failed to exec '%s': %s"), path, strerror(errno));
 167 }
 168
 169 static void exec_man_cmd(const char *cmd, const char *page)
 170 {
 171         struct strbuf shell_cmd = STRBUF_INIT;
 172         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 173         execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
 174         warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
 175 }
 176
 177 static void add_man_viewer(const char *name)
 178 {
 179         struct man_viewer_list **p = &man_viewer_list;
 180         size_t len = strlen(name);
 181
 182         while (*p)
 183                 p = &((*p)->next);
 184         *p = xcalloc(1, (sizeof(**p) + len + 1));
 185         strncpy((*p)->name, name, len);
 186 }
 187
 188 static int supported_man_viewer(const char *name, size_t len)
 189 {
 190         return (!strncasecmp("man", name, len) ||
 191                 !strncasecmp("woman", name, len) ||
 192                 !strncasecmp("konqueror", name, len));
 193 }
 194
 195 static void do_add_man_viewer_info(const char *name,
 196                                    size_t len,
 197                                    const char *value)
 198 {
 199         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 200
 201         strncpy(new->name, name, len);
 202         new->info = xstrdup(value);
 203         new->next = man_viewer_info_list;
 204         man_viewer_info_list = new;
 205 }
 206
 207 static int add_man_viewer_path(const char *name,
 208                                size_t len,
 209                                const char *value)
 210 {
 211         if (supported_man_viewer(name, len))
 212                 do_add_man_viewer_info(name, len, value);
 213         else
 214                 warning(_("'%s': path for unsupported man viewer.\n"
 215                           "Please consider using 'man.<tool>.cmd' instead."),
 216                         name);
 217
 218         return 0;
 219 }
 220
 221 static int add_man_viewer_cmd(const char *name,
 222                               size_t len,
 223                               const char *value)
 224 {
 225         if (supported_man_viewer(name, len))
 226                 warning(_("'%s': cmd for supported man viewer.\n"
 227                           "Please consider using 'man.<tool>.path' instead."),
 228                         name);
 229         else
 230                 do_add_man_viewer_info(name, len, value);
 231
 232         return 0;
 233 }
 234
 235 static int add_man_viewer_info(const char *var, const char *value)
 236 {
 237         const char *name = var + 4;
 238         const char *subkey = strrchr(name, '.');
 239
 240         if (!subkey)
 241                 return 0;
 242
 243         if (!strcmp(subkey, ".path")) {
 244                 if (!value)
 245                         return config_error_nonbool(var);
 246                 return add_man_viewer_path(name, subkey - name, value);
 247         }
 248         if (!strcmp(subkey, ".cmd")) {
 249                 if (!value)
 250                         return config_error_nonbool(var);
 251                 return add_man_viewer_cmd(name, subkey - name, value);
 252         }
 253
 254         return 0;
 255 }
 256
 257 static int git_help_config(const char *var, const char *value, void *cb)
 258 {
 259         if (!prefixcmp(var, "column."))
 260                 return git_column_config(var, value, "help", &colopts);
 261         if (!strcmp(var, "help.format")) {
 262                 if (!value)
 263                         return config_error_nonbool(var);
 264                 help_format = parse_help_format(value);
 265                 return 0;
 266         }
 267         if (!strcmp(var, "help.htmlpath")) {
 268                 if (!value)
 269                         return config_error_nonbool(var);
 270                 html_path = xstrdup(value);
 271                 return 0;
 272         }
 273         if (!strcmp(var, "man.viewer")) {
 274                 if (!value)
 275                         return config_error_nonbool(var);
 276                 add_man_viewer(value);
 277                 return 0;
 278         }
 279         if (!prefixcmp(var, "man."))
 280                 return add_man_viewer_info(var, value);
 281
 282         return git_default_config(var, value, cb);
 283 }
 284
 285 static struct cmdnames main_cmds, other_cmds;
 286
 287 static int is_git_command(const char *s)
 288 {
 289         return is_in_cmdlist(&main_cmds, s) ||
 290                 is_in_cmdlist(&other_cmds, s);
 291 }
 292
 293 static const char *prepend(const char *prefix, const char *cmd)
 294 {
 295         size_t pre_len = strlen(prefix);
 296         size_t cmd_len = strlen(cmd);
 297         char *p = xmalloc(pre_len + cmd_len + 1);
 298         memcpy(p, prefix, pre_len);
 299         strcpy(p + pre_len, cmd);
 300         return p;
 301 }
 302
 303 static const char *cmd_to_page(const char *git_cmd)
 304 {
 305         if (!git_cmd)
 306                 return "git";
 307         else if (!prefixcmp(git_cmd, "git"))
 308                 return git_cmd;
 309         else if (is_git_command(git_cmd))
 310                 return prepend("git-", git_cmd);
 311         else
 312                 return prepend("git", git_cmd);
 313 }
 314
 315 static void setup_man_path(void)
 316 {
 317         struct strbuf new_path = STRBUF_INIT;
 318         const char *old_path = getenv("MANPATH");
 319
 320         /* We should always put ':' after our path. If there is no
 321          * old_path, the ':' at the end will let 'man' to try
 322          * system-wide paths after ours to find the manual page. If
 323          * there is old_path, we need ':' as delimiter. */
 324         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
 325         strbuf_addch(&new_path, ':');
 326         if (old_path)
 327                 strbuf_addstr(&new_path, old_path);
 328
 329         setenv("MANPATH", new_path.buf, 1);
 330
 331         strbuf_release(&new_path);
 332 }
 333
 334 static void exec_viewer(const char *name, const char *page)
 335 {
 336         const char *info = get_man_viewer_info(name);
 337
 338         if (!strcasecmp(name, "man"))
 339                 exec_man_man(info, page);
 340         else if (!strcasecmp(name, "woman"))
 341                 exec_woman_emacs(info, page);
 342         else if (!strcasecmp(name, "konqueror"))
 343                 exec_man_konqueror(info, page);
 344         else if (info)
 345                 exec_man_cmd(info, page);
 346         else
 347                 warning(_("'%s': unknown man viewer."), name);
 348 }
 349
 350 static void show_man_page(const char *git_cmd)
 351 {
 352         struct man_viewer_list *viewer;
 353         const char *page = cmd_to_page(git_cmd);
 354         const char *fallback = getenv("GIT_MAN_VIEWER");
 355
 356         setup_man_path();
 357         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 358         {
 359                 exec_viewer(viewer->name, page); /* will return when unable */
 360         }
 361         if (fallback)
 362                 exec_viewer(fallback, page);
 363         exec_viewer("man", page);
 364         die(_("no man viewer handled the request"));
 365 }
 366
 367 static void show_info_page(const char *git_cmd)
 368 {
 369         const char *page = cmd_to_page(git_cmd);
 370         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 371         execlp("info", "info", "gitman", page, (char *)NULL);
 372         die(_("no info viewer handled the request"));
 373 }
 374
 375 static void get_html_page_path(struct strbuf *page_path, const char *page)
 376 {
 377         struct stat st;
 378         if (!html_path)
 379                 html_path = system_path(GIT_HTML_PATH);
 380
 381         /* Check that we have a git documentation directory. */
 382         if (!strstr(html_path, "://")) {
 383                 if (stat(mkpath("%s/git.html", html_path), &st)
 384                     || !S_ISREG(st.st_mode))
 385                         die("'%s': not a documentation directory.", html_path);
 386         }
 387
 388         strbuf_init(page_path, 0);
 389         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 390 }
 391
 392 /*
 393  * If open_html is not defined in a platform-specific way (see for
 394  * example compat/mingw.h), we use the script web--browse to display
 395  * HTML.
 396  */
 397 #ifndef open_html
 398 static void open_html(const char *path)
 399 {
 400         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 401 }
 402 #endif
 403
 404 static void show_html_page(const char *git_cmd)
 405 {
 406         const char *page = cmd_to_page(git_cmd);
 407         struct strbuf page_path; /* it leaks but we exec bellow */
 408
 409         get_html_page_path(&page_path, page);
 410
 411         open_html(page_path.buf);
 412 }
 413
 414 int cmd_help(int argc, const char **argv, const char *prefix)
 415 {
 416         int nongit;
 417         const char *alias;
 418         enum help_format parsed_help_format;
 419         load_command_list("git-", &main_cmds, &other_cmds);
 420
 421         argc = parse_options(argc, argv, prefix, builtin_help_options,
 422                         builtin_help_usage, 0);
 423         parsed_help_format = help_format;
 424
 425         if (show_all) {
 426                 git_config(git_help_config, NULL);
 427                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 428                 list_commands(colopts, &main_cmds, &other_cmds);
 429                 printf("%s\n", _(git_more_info_string));
 430                 return 0;
 431         }
 432
 433         if (!argv[0]) {
 434                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 435                 list_common_cmds_help();
 436                 printf("\n%s\n", _(git_more_info_string));
 437                 return 0;
 438         }
 439
 440         setup_git_directory_gently(&nongit);
 441         git_config(git_help_config, NULL);
 442
 443         if (parsed_help_format != HELP_FORMAT_NONE)
 444                 help_format = parsed_help_format;
 445         if (help_format == HELP_FORMAT_NONE)
 446                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 447
 448         alias = alias_lookup(argv[0]);
 449         if (alias && !is_git_command(argv[0])) {
 450                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 451                 return 0;
 452         }
 453
 454         switch (help_format) {
 455         case HELP_FORMAT_NONE:
 456         case HELP_FORMAT_MAN:
 457                 show_man_page(argv[0]);
 458                 break;
 459         case HELP_FORMAT_INFO:
 460                 show_info_page(argv[0]);
 461                 break;
 462         case HELP_FORMAT_WEB:
 463                 show_html_page(argv[0]);
 464                 break;
 465         }
 466
 467         return 0;
 468 }