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   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 int show_all = 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_BOOLEAN('a', "all", &show_all, "print all available commands"),
  42         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  43         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  44                         HELP_FORMAT_WEB),
  45         OPT_SET_INT('i', "info", &help_format, "show info page",
  46                         HELP_FORMAT_INFO),
  47         OPT_END(),
  48 };
  49
  50 static const char * const builtin_help_usage[] = {
  51         "git help [--all] [--man|--web|--info] [command]",
  52         NULL
  53 };
  54
  55 static enum help_format parse_help_format(const char *format)
  56 {
  57         if (!strcmp(format, "man"))
  58                 return HELP_FORMAT_MAN;
  59         if (!strcmp(format, "info"))
  60                 return HELP_FORMAT_INFO;
  61         if (!strcmp(format, "web") || !strcmp(format, "html"))
  62                 return HELP_FORMAT_WEB;
  63         die(_("unrecognized help format '%s'"), format);
  64 }
  65
  66 static const char *get_man_viewer_info(const char *name)
  67 {
  68         struct man_viewer_info_list *viewer;
  69
  70         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  71         {
  72                 if (!strcasecmp(name, viewer->name))
  73                         return viewer->info;
  74         }
  75         return NULL;
  76 }
  77
  78 static int check_emacsclient_version(void)
  79 {
  80         struct strbuf buffer = STRBUF_INIT;
  81         struct child_process ec_process;
  82         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  83         int version;
  84
  85         /* emacsclient prints its version number on stderr */
  86         memset(&ec_process, 0, sizeof(ec_process));
  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 (prefixcmp(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("/bin/sh", "sh", "-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 = var + 4;
 239         const char *subkey = strrchr(name, '.');
 240
 241         if (!subkey)
 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, subkey - name, value);
 248         }
 249         if (!strcmp(subkey, ".cmd")) {
 250                 if (!value)
 251                         return config_error_nonbool(var);
 252                 return add_man_viewer_cmd(name, subkey - name, 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 (!prefixcmp(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, "man.viewer")) {
 269                 if (!value)
 270                         return config_error_nonbool(var);
 271                 add_man_viewer(value);
 272                 return 0;
 273         }
 274         if (!prefixcmp(var, "man."))
 275                 return add_man_viewer_info(var, value);
 276
 277         return git_default_config(var, value, cb);
 278 }
 279
 280 static struct cmdnames main_cmds, other_cmds;
 281
 282 void list_common_cmds_help(void)
 283 {
 284         int i, longest = 0;
 285
 286         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 287                 if (longest < strlen(common_cmds[i].name))
 288                         longest = strlen(common_cmds[i].name);
 289         }
 290
 291         puts(_("The most commonly used git commands are:"));
 292         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 293                 printf("   %s   ", common_cmds[i].name);
 294                 mput_char(' ', longest - strlen(common_cmds[i].name));
 295                 puts(_(common_cmds[i].help));
 296         }
 297 }
 298
 299 static int is_git_command(const char *s)
 300 {
 301         return is_in_cmdlist(&main_cmds, s) ||
 302                 is_in_cmdlist(&other_cmds, s);
 303 }
 304
 305 static const char *prepend(const char *prefix, const char *cmd)
 306 {
 307         size_t pre_len = strlen(prefix);
 308         size_t cmd_len = strlen(cmd);
 309         char *p = xmalloc(pre_len + cmd_len + 1);
 310         memcpy(p, prefix, pre_len);
 311         strcpy(p + pre_len, cmd);
 312         return p;
 313 }
 314
 315 static const char *cmd_to_page(const char *git_cmd)
 316 {
 317         if (!git_cmd)
 318                 return "git";
 319         else if (!prefixcmp(git_cmd, "git"))
 320                 return git_cmd;
 321         else if (is_git_command(git_cmd))
 322                 return prepend("git-", git_cmd);
 323         else
 324                 return prepend("git", git_cmd);
 325 }
 326
 327 static void setup_man_path(void)
 328 {
 329         struct strbuf new_path = STRBUF_INIT;
 330         const char *old_path = getenv("MANPATH");
 331
 332         /* We should always put ':' after our path. If there is no
 333          * old_path, the ':' at the end will let 'man' to try
 334          * system-wide paths after ours to find the manual page. If
 335          * there is old_path, we need ':' as delimiter. */
 336         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
 337         strbuf_addch(&new_path, ':');
 338         if (old_path)
 339                 strbuf_addstr(&new_path, old_path);
 340
 341         setenv("MANPATH", new_path.buf, 1);
 342
 343         strbuf_release(&new_path);
 344 }
 345
 346 static void exec_viewer(const char *name, const char *page)
 347 {
 348         const char *info = get_man_viewer_info(name);
 349
 350         if (!strcasecmp(name, "man"))
 351                 exec_man_man(info, page);
 352         else if (!strcasecmp(name, "woman"))
 353                 exec_woman_emacs(info, page);
 354         else if (!strcasecmp(name, "konqueror"))
 355                 exec_man_konqueror(info, page);
 356         else if (info)
 357                 exec_man_cmd(info, page);
 358         else
 359                 warning(_("'%s': unknown man viewer."), name);
 360 }
 361
 362 static void show_man_page(const char *git_cmd)
 363 {
 364         struct man_viewer_list *viewer;
 365         const char *page = cmd_to_page(git_cmd);
 366         const char *fallback = getenv("GIT_MAN_VIEWER");
 367
 368         setup_man_path();
 369         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 370         {
 371                 exec_viewer(viewer->name, page); /* will return when unable */
 372         }
 373         if (fallback)
 374                 exec_viewer(fallback, page);
 375         exec_viewer("man", page);
 376         die(_("no man viewer handled the request"));
 377 }
 378
 379 static void show_info_page(const char *git_cmd)
 380 {
 381         const char *page = cmd_to_page(git_cmd);
 382         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 383         execlp("info", "info", "gitman", page, (char *)NULL);
 384         die(_("no info viewer handled the request"));
 385 }
 386
 387 static void get_html_page_path(struct strbuf *page_path, const char *page)
 388 {
 389         struct stat st;
 390         const char *html_path = system_path(GIT_HTML_PATH);
 391
 392         /* Check that we have a git documentation directory. */
 393         if (stat(mkpath("%s/git.html", html_path), &st)
 394             || !S_ISREG(st.st_mode))
 395                 die(_("'%s': not a documentation directory."), html_path);
 396
 397         strbuf_init(page_path, 0);
 398         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 399 }
 400
 401 /*
 402  * If open_html is not defined in a platform-specific way (see for
 403  * example compat/mingw.h), we use the script web--browse to display
 404  * HTML.
 405  */
 406 #ifndef open_html
 407 static void open_html(const char *path)
 408 {
 409         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 410 }
 411 #endif
 412
 413 static void show_html_page(const char *git_cmd)
 414 {
 415         const char *page = cmd_to_page(git_cmd);
 416         struct strbuf page_path; /* it leaks but we exec bellow */
 417
 418         get_html_page_path(&page_path, page);
 419
 420         open_html(page_path.buf);
 421 }
 422
 423 int cmd_help(int argc, const char **argv, const char *prefix)
 424 {
 425         int nongit;
 426         const char *alias;
 427         enum help_format parsed_help_format;
 428         load_command_list("git-", &main_cmds, &other_cmds);
 429
 430         argc = parse_options(argc, argv, prefix, builtin_help_options,
 431                         builtin_help_usage, 0);
 432         parsed_help_format = help_format;
 433
 434         if (show_all) {
 435                 git_config(git_help_config, NULL);
 436                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 437                 list_commands(colopts, &main_cmds, &other_cmds);
 438                 printf("%s\n", _(git_more_info_string));
 439                 return 0;
 440         }
 441
 442         if (!argv[0]) {
 443                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 444                 list_common_cmds_help();
 445                 printf("\n%s\n", _(git_more_info_string));
 446                 return 0;
 447         }
 448
 449         setup_git_directory_gently(&nongit);
 450         git_config(git_help_config, NULL);
 451
 452         if (parsed_help_format != HELP_FORMAT_NONE)
 453                 help_format = parsed_help_format;
 454         if (help_format == HELP_FORMAT_NONE)
 455                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 456
 457         alias = alias_lookup(argv[0]);
 458         if (alias && !is_git_command(argv[0])) {
 459                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 460                 return 0;
 461         }
 462
 463         switch (help_format) {
 464         case HELP_FORMAT_NONE:
 465         case HELP_FORMAT_MAN:
 466                 show_man_page(argv[0]);
 467                 break;
 468         case HELP_FORMAT_INFO:
 469                 show_info_page(argv[0]);
 470                 break;
 471         case HELP_FORMAT_WEB:
 472                 show_html_page(argv[0]);
 473                 break;
 474         }
 475
 476         return 0;
 477 }