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;
  83         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  84         int version;
  85
  86         /* emacsclient prints its version number on stderr */
  87         memset(&ec_process, 0, sizeof(ec_process));
  88         ec_process.argv = argv_ec;
  89         ec_process.err = -1;
  90         ec_process.stdout_to_stderr = 1;
  91         if (start_command(&ec_process))
  92                 return error(_("Failed to start emacsclient."));
  93
  94         strbuf_read(&buffer, ec_process.err, 20);
  95         close(ec_process.err);
  96
  97         /*
  98          * Don't bother checking return value, because "emacsclient --version"
  99          * seems to always exits with code 1.
 100          */
 101         finish_command(&ec_process);
 102
 103         if (!starts_with(buffer.buf, "emacsclient")) {
 104                 strbuf_release(&buffer);
 105                 return error(_("Failed to parse emacsclient version."));
 106         }
 107
 108         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 109         version = atoi(buffer.buf);
 110
 111         if (version < 22) {
 112                 strbuf_release(&buffer);
 113                 return error(_("emacsclient version '%d' too old (< 22)."),
 114                         version);
 115         }
 116
 117         strbuf_release(&buffer);
 118         return 0;
 119 }
 120
 121 static void exec_woman_emacs(const char *path, const char *page)
 122 {
 123         if (!check_emacsclient_version()) {
 124                 /* This works only with emacsclient version >= 22. */
 125                 struct strbuf man_page = STRBUF_INIT;
 126
 127                 if (!path)
 128                         path = "emacsclient";
 129                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 130                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 131                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 132         }
 133 }
 134
 135 static void exec_man_konqueror(const char *path, const char *page)
 136 {
 137         const char *display = getenv("DISPLAY");
 138         if (display && *display) {
 139                 struct strbuf man_page = STRBUF_INIT;
 140                 const char *filename = "kfmclient";
 141
 142                 /* It's simpler to launch konqueror using kfmclient. */
 143                 if (path) {
 144                         const char *file = strrchr(path, '/');
 145                         if (file && !strcmp(file + 1, "konqueror")) {
 146                                 char *new = xstrdup(path);
 147                                 char *dest = strrchr(new, '/');
 148
 149                                 /* strlen("konqueror") == strlen("kfmclient") */
 150                                 strcpy(dest + 1, "kfmclient");
 151                                 path = new;
 152                         }
 153                         if (file)
 154                                 filename = file;
 155                 } else
 156                         path = "kfmclient";
 157                 strbuf_addf(&man_page, "man:%s(1)", page);
 158                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 159                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 160         }
 161 }
 162
 163 static void exec_man_man(const char *path, const char *page)
 164 {
 165         if (!path)
 166                 path = "man";
 167         execlp(path, "man", page, (char *)NULL);
 168         warning(_("failed to exec '%s': %s"), path, strerror(errno));
 169 }
 170
 171 static void exec_man_cmd(const char *cmd, const char *page)
 172 {
 173         struct strbuf shell_cmd = STRBUF_INIT;
 174         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 175         execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
 176         warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
 177 }
 178
 179 static void add_man_viewer(const char *name)
 180 {
 181         struct man_viewer_list **p = &man_viewer_list;
 182         size_t len = strlen(name);
 183
 184         while (*p)
 185                 p = &((*p)->next);
 186         *p = xcalloc(1, (sizeof(**p) + len + 1));
 187         strncpy((*p)->name, name, len);
 188 }
 189
 190 static int supported_man_viewer(const char *name, size_t len)
 191 {
 192         return (!strncasecmp("man", name, len) ||
 193                 !strncasecmp("woman", name, len) ||
 194                 !strncasecmp("konqueror", name, len));
 195 }
 196
 197 static void do_add_man_viewer_info(const char *name,
 198                                    size_t len,
 199                                    const char *value)
 200 {
 201         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 202
 203         strncpy(new->name, name, len);
 204         new->info = xstrdup(value);
 205         new->next = man_viewer_info_list;
 206         man_viewer_info_list = new;
 207 }
 208
 209 static int add_man_viewer_path(const char *name,
 210                                size_t len,
 211                                const char *value)
 212 {
 213         if (supported_man_viewer(name, len))
 214                 do_add_man_viewer_info(name, len, value);
 215         else
 216                 warning(_("'%s': path for unsupported man viewer.\n"
 217                           "Please consider using 'man.<tool>.cmd' instead."),
 218                         name);
 219
 220         return 0;
 221 }
 222
 223 static int add_man_viewer_cmd(const char *name,
 224                               size_t len,
 225                               const char *value)
 226 {
 227         if (supported_man_viewer(name, len))
 228                 warning(_("'%s': cmd for supported man viewer.\n"
 229                           "Please consider using 'man.<tool>.path' instead."),
 230                         name);
 231         else
 232                 do_add_man_viewer_info(name, len, value);
 233
 234         return 0;
 235 }
 236
 237 static int add_man_viewer_info(const char *var, const char *value)
 238 {
 239         const char *name, *subkey;
 240         int namelen;
 241
 242         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 243                 return 0;
 244
 245         if (!strcmp(subkey, "path")) {
 246                 if (!value)
 247                         return config_error_nonbool(var);
 248                 return add_man_viewer_path(name, namelen, value);
 249         }
 250         if (!strcmp(subkey, "cmd")) {
 251                 if (!value)
 252                         return config_error_nonbool(var);
 253                 return add_man_viewer_cmd(name, namelen, value);
 254         }
 255
 256         return 0;
 257 }
 258
 259 static int git_help_config(const char *var, const char *value, void *cb)
 260 {
 261         if (starts_with(var, "column."))
 262                 return git_column_config(var, value, "help", &colopts);
 263         if (!strcmp(var, "help.format")) {
 264                 if (!value)
 265                         return config_error_nonbool(var);
 266                 help_format = parse_help_format(value);
 267                 return 0;
 268         }
 269         if (!strcmp(var, "help.htmlpath")) {
 270                 if (!value)
 271                         return config_error_nonbool(var);
 272                 html_path = xstrdup(value);
 273                 return 0;
 274         }
 275         if (!strcmp(var, "man.viewer")) {
 276                 if (!value)
 277                         return config_error_nonbool(var);
 278                 add_man_viewer(value);
 279                 return 0;
 280         }
 281         if (starts_with(var, "man."))
 282                 return add_man_viewer_info(var, value);
 283
 284         return git_default_config(var, value, cb);
 285 }
 286
 287 static struct cmdnames main_cmds, other_cmds;
 288
 289 static int is_git_command(const char *s)
 290 {
 291         if (is_builtin(s))
 292                 return 1;
 293
 294         load_command_list("git-", &main_cmds, &other_cmds);
 295         return is_in_cmdlist(&main_cmds, s) ||
 296                 is_in_cmdlist(&other_cmds, s);
 297 }
 298
 299 static const char *prepend(const char *prefix, const char *cmd)
 300 {
 301         size_t pre_len = strlen(prefix);
 302         size_t cmd_len = strlen(cmd);
 303         char *p = xmalloc(pre_len + cmd_len + 1);
 304         memcpy(p, prefix, pre_len);
 305         strcpy(p + pre_len, cmd);
 306         return p;
 307 }
 308
 309 static const char *cmd_to_page(const char *git_cmd)
 310 {
 311         if (!git_cmd)
 312                 return "git";
 313         else if (starts_with(git_cmd, "git"))
 314                 return git_cmd;
 315         else if (is_git_command(git_cmd))
 316                 return prepend("git-", git_cmd);
 317         else
 318                 return prepend("git", git_cmd);
 319 }
 320
 321 static void setup_man_path(void)
 322 {
 323         struct strbuf new_path = STRBUF_INIT;
 324         const char *old_path = getenv("MANPATH");
 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, system_path(GIT_MAN_PATH));
 331         strbuf_addch(&new_path, ':');
 332         if (old_path)
 333                 strbuf_addstr(&new_path, old_path);
 334
 335         setenv("MANPATH", new_path.buf, 1);
 336
 337         strbuf_release(&new_path);
 338 }
 339
 340 static void exec_viewer(const char *name, const char *page)
 341 {
 342         const char *info = get_man_viewer_info(name);
 343
 344         if (!strcasecmp(name, "man"))
 345                 exec_man_man(info, page);
 346         else if (!strcasecmp(name, "woman"))
 347                 exec_woman_emacs(info, page);
 348         else if (!strcasecmp(name, "konqueror"))
 349                 exec_man_konqueror(info, page);
 350         else if (info)
 351                 exec_man_cmd(info, page);
 352         else
 353                 warning(_("'%s': unknown man viewer."), name);
 354 }
 355
 356 static void show_man_page(const char *git_cmd)
 357 {
 358         struct man_viewer_list *viewer;
 359         const char *page = cmd_to_page(git_cmd);
 360         const char *fallback = getenv("GIT_MAN_VIEWER");
 361
 362         setup_man_path();
 363         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 364         {
 365                 exec_viewer(viewer->name, page); /* will return when unable */
 366         }
 367         if (fallback)
 368                 exec_viewer(fallback, page);
 369         exec_viewer("man", page);
 370         die(_("no man viewer handled the request"));
 371 }
 372
 373 static void show_info_page(const char *git_cmd)
 374 {
 375         const char *page = cmd_to_page(git_cmd);
 376         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 377         execlp("info", "info", "gitman", page, (char *)NULL);
 378         die(_("no info viewer handled the request"));
 379 }
 380
 381 static void get_html_page_path(struct strbuf *page_path, const char *page)
 382 {
 383         struct stat st;
 384         if (!html_path)
 385                 html_path = system_path(GIT_HTML_PATH);
 386
 387         /* Check that we have a git documentation directory. */
 388         if (!strstr(html_path, "://")) {
 389                 if (stat(mkpath("%s/git.html", html_path), &st)
 390                     || !S_ISREG(st.st_mode))
 391                         die("'%s': not a documentation directory.", html_path);
 392         }
 393
 394         strbuf_init(page_path, 0);
 395         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 396 }
 397
 398 /*
 399  * If open_html is not defined in a platform-specific way (see for
 400  * example compat/mingw.h), we use the script web--browse to display
 401  * HTML.
 402  */
 403 #ifndef open_html
 404 static void open_html(const char *path)
 405 {
 406         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 407 }
 408 #endif
 409
 410 static void show_html_page(const char *git_cmd)
 411 {
 412         const char *page = cmd_to_page(git_cmd);
 413         struct strbuf page_path; /* it leaks but we exec bellow */
 414
 415         get_html_page_path(&page_path, page);
 416
 417         open_html(page_path.buf);
 418 }
 419
 420 static struct {
 421         const char *name;
 422         const char *help;
 423 } common_guides[] = {
 424         { "attributes", N_("Defining attributes per path") },
 425         { "glossary", N_("A Git glossary") },
 426         { "ignore", N_("Specifies intentionally untracked files to ignore") },
 427         { "modules", N_("Defining submodule properties") },
 428         { "revisions", N_("Specifying revisions and ranges for Git") },
 429         { "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
 430         { "workflows", N_("An overview of recommended workflows with Git") },
 431 };
 432
 433 static void list_common_guides_help(void)
 434 {
 435         int i, longest = 0;
 436
 437         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 438                 if (longest < strlen(common_guides[i].name))
 439                         longest = strlen(common_guides[i].name);
 440         }
 441
 442         puts(_("The common Git guides are:\n"));
 443         for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
 444                 printf("   %s   ", common_guides[i].name);
 445                 mput_char(' ', longest - strlen(common_guides[i].name));
 446                 puts(_(common_guides[i].help));
 447         }
 448         putchar('\n');
 449 }
 450
 451 int cmd_help(int argc, const char **argv, const char *prefix)
 452 {
 453         int nongit;
 454         const char *alias;
 455         enum help_format parsed_help_format;
 456
 457         argc = parse_options(argc, argv, prefix, builtin_help_options,
 458                         builtin_help_usage, 0);
 459         parsed_help_format = help_format;
 460
 461         if (show_all) {
 462                 git_config(git_help_config, NULL);
 463                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 464                 load_command_list("git-", &main_cmds, &other_cmds);
 465                 list_commands(colopts, &main_cmds, &other_cmds);
 466         }
 467
 468         if (show_guides)
 469                 list_common_guides_help();
 470
 471         if (show_all || show_guides) {
 472                 printf("%s\n", _(git_more_info_string));
 473                 /*
 474                 * We're done. Ignore any remaining args
 475                 */
 476                 return 0;
 477         }
 478
 479         if (!argv[0]) {
 480                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 481                 list_common_cmds_help();
 482                 printf("\n%s\n", _(git_more_info_string));
 483                 return 0;
 484         }
 485
 486         setup_git_directory_gently(&nongit);
 487         git_config(git_help_config, NULL);
 488
 489         if (parsed_help_format != HELP_FORMAT_NONE)
 490                 help_format = parsed_help_format;
 491         if (help_format == HELP_FORMAT_NONE)
 492                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 493
 494         alias = alias_lookup(argv[0]);
 495         if (alias && !is_git_command(argv[0])) {
 496                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 497                 return 0;
 498         }
 499
 500         switch (help_format) {
 501         case HELP_FORMAT_NONE:
 502         case HELP_FORMAT_MAN:
 503                 show_man_page(argv[0]);
 504                 break;
 505         case HELP_FORMAT_INFO:
 506                 show_info_page(argv[0]);
 507                 break;
 508         case HELP_FORMAT_WEB:
 509                 show_html_page(argv[0]);
 510                 break;
 511         }
 512
 513         return 0;
 514 }