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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 "help.h"
  13
  14 static struct man_viewer_list {
  15         struct man_viewer_list *next;
  16         char name[FLEX_ARRAY];
  17 } *man_viewer_list;
  18
  19 static struct man_viewer_info_list {
  20         struct man_viewer_info_list *next;
  21         const char *info;
  22         char name[FLEX_ARRAY];
  23 } *man_viewer_info_list;
  24
  25 enum help_format {
  26         HELP_FORMAT_MAN,
  27         HELP_FORMAT_INFO,
  28         HELP_FORMAT_WEB,
  29 };
  30
  31 static int show_all = 0;
  32 static enum help_format help_format = HELP_FORMAT_MAN;
  33 static struct option builtin_help_options[] = {
  34         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
  35         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  36         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  37                         HELP_FORMAT_WEB),
  38         OPT_SET_INT('i', "info", &help_format, "show info page",
  39                         HELP_FORMAT_INFO),
  40         OPT_END(),
  41 };
  42
  43 static const char * const builtin_help_usage[] = {
  44         "git help [--all] [--man|--web|--info] [command]",
  45         NULL
  46 };
  47
  48 static enum help_format parse_help_format(const char *format)
  49 {
  50         if (!strcmp(format, "man"))
  51                 return HELP_FORMAT_MAN;
  52         if (!strcmp(format, "info"))
  53                 return HELP_FORMAT_INFO;
  54         if (!strcmp(format, "web") || !strcmp(format, "html"))
  55                 return HELP_FORMAT_WEB;
  56         die("unrecognized help format '%s'", format);
  57 }
  58
  59 static const char *get_man_viewer_info(const char *name)
  60 {
  61         struct man_viewer_info_list *viewer;
  62
  63         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  64         {
  65                 if (!strcasecmp(name, viewer->name))
  66                         return viewer->info;
  67         }
  68         return NULL;
  69 }
  70
  71 static int check_emacsclient_version(void)
  72 {
  73         struct strbuf buffer = STRBUF_INIT;
  74         struct child_process ec_process;
  75         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  76         int version;
  77
  78         /* emacsclient prints its version number on stderr */
  79         memset(&ec_process, 0, sizeof(ec_process));
  80         ec_process.argv = argv_ec;
  81         ec_process.err = -1;
  82         ec_process.stdout_to_stderr = 1;
  83         if (start_command(&ec_process)) {
  84                 fprintf(stderr, "Failed to start emacsclient.\n");
  85                 return -1;
  86         }
  87         strbuf_read(&buffer, ec_process.err, 20);
  88         close(ec_process.err);
  89
  90         /*
  91          * Don't bother checking return value, because "emacsclient --version"
  92          * seems to always exits with code 1.
  93          */
  94         finish_command(&ec_process);
  95
  96         if (prefixcmp(buffer.buf, "emacsclient")) {
  97                 fprintf(stderr, "Failed to parse emacsclient version.\n");
  98                 strbuf_release(&buffer);
  99                 return -1;
 100         }
 101
 102         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 103         version = atoi(buffer.buf);
 104
 105         if (version < 22) {
 106                 fprintf(stderr,
 107                         "emacsclient version '%d' too old (< 22).\n",
 108                         version);
 109                 strbuf_release(&buffer);
 110                 return -1;
 111         }
 112
 113         strbuf_release(&buffer);
 114         return 0;
 115 }
 116
 117 static void exec_woman_emacs(const char *path, const char *page)
 118 {
 119         if (!check_emacsclient_version()) {
 120                 /* This works only with emacsclient version >= 22. */
 121                 struct strbuf man_page = STRBUF_INIT;
 122
 123                 if (!path)
 124                         path = "emacsclient";
 125                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 126                 execlp(path, "emacsclient", "-e", man_page.buf, NULL);
 127                 warning("failed to exec '%s': %s", path, strerror(errno));
 128         }
 129 }
 130
 131 static void exec_man_konqueror(const char *path, const char *page)
 132 {
 133         const char *display = getenv("DISPLAY");
 134         if (display && *display) {
 135                 struct strbuf man_page = STRBUF_INIT;
 136                 const char *filename = "kfmclient";
 137
 138                 /* It's simpler to launch konqueror using kfmclient. */
 139                 if (path) {
 140                         const char *file = strrchr(path, '/');
 141                         if (file && !strcmp(file + 1, "konqueror")) {
 142                                 char *new = xstrdup(path);
 143                                 char *dest = strrchr(new, '/');
 144
 145                                 /* strlen("konqueror") == strlen("kfmclient") */
 146                                 strcpy(dest + 1, "kfmclient");
 147                                 path = new;
 148                         }
 149                         if (file)
 150                                 filename = file;
 151                 } else
 152                         path = "kfmclient";
 153                 strbuf_addf(&man_page, "man:%s(1)", page);
 154                 execlp(path, filename, "newTab", man_page.buf, NULL);
 155                 warning("failed to exec '%s': %s", path, strerror(errno));
 156         }
 157 }
 158
 159 static void exec_man_man(const char *path, const char *page)
 160 {
 161         if (!path)
 162                 path = "man";
 163         execlp(path, "man", page, NULL);
 164         warning("failed to exec '%s': %s", path, strerror(errno));
 165 }
 166
 167 static void exec_man_cmd(const char *cmd, const char *page)
 168 {
 169         struct strbuf shell_cmd = STRBUF_INIT;
 170         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 171         execl("/bin/sh", "sh", "-c", shell_cmd.buf, NULL);
 172         warning("failed to exec '%s': %s", cmd, strerror(errno));
 173 }
 174
 175 static void add_man_viewer(const char *name)
 176 {
 177         struct man_viewer_list **p = &man_viewer_list;
 178         size_t len = strlen(name);
 179
 180         while (*p)
 181                 p = &((*p)->next);
 182         *p = xcalloc(1, (sizeof(**p) + len + 1));
 183         strncpy((*p)->name, name, len);
 184 }
 185
 186 static int supported_man_viewer(const char *name, size_t len)
 187 {
 188         return (!strncasecmp("man", name, len) ||
 189                 !strncasecmp("woman", name, len) ||
 190                 !strncasecmp("konqueror", name, len));
 191 }
 192
 193 static void do_add_man_viewer_info(const char *name,
 194                                    size_t len,
 195                                    const char *value)
 196 {
 197         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 198
 199         strncpy(new->name, name, len);
 200         new->info = xstrdup(value);
 201         new->next = man_viewer_info_list;
 202         man_viewer_info_list = new;
 203 }
 204
 205 static int add_man_viewer_path(const char *name,
 206                                size_t len,
 207                                const char *value)
 208 {
 209         if (supported_man_viewer(name, len))
 210                 do_add_man_viewer_info(name, len, value);
 211         else
 212                 warning("'%s': path for unsupported man viewer.\n"
 213                         "Please consider using 'man.<tool>.cmd' instead.",
 214                         name);
 215
 216         return 0;
 217 }
 218
 219 static int add_man_viewer_cmd(const char *name,
 220                               size_t len,
 221                               const char *value)
 222 {
 223         if (supported_man_viewer(name, len))
 224                 warning("'%s': cmd for supported man viewer.\n"
 225                         "Please consider using 'man.<tool>.path' instead.",
 226                         name);
 227         else
 228                 do_add_man_viewer_info(name, len, value);
 229
 230         return 0;
 231 }
 232
 233 static int add_man_viewer_info(const char *var, const char *value)
 234 {
 235         const char *name = var + 4;
 236         const char *subkey = strrchr(name, '.');
 237
 238         if (!subkey)
 239                 return 0;
 240
 241         if (!strcmp(subkey, ".path")) {
 242                 if (!value)
 243                         return config_error_nonbool(var);
 244                 return add_man_viewer_path(name, subkey - name, value);
 245         }
 246         if (!strcmp(subkey, ".cmd")) {
 247                 if (!value)
 248                         return config_error_nonbool(var);
 249                 return add_man_viewer_cmd(name, subkey - name, value);
 250         }
 251
 252         return 0;
 253 }
 254
 255 static int git_help_config(const char *var, const char *value, void *cb)
 256 {
 257         if (!strcmp(var, "help.format")) {
 258                 if (!value)
 259                         return config_error_nonbool(var);
 260                 help_format = parse_help_format(value);
 261                 return 0;
 262         }
 263         if (!strcmp(var, "man.viewer")) {
 264                 if (!value)
 265                         return config_error_nonbool(var);
 266                 add_man_viewer(value);
 267                 return 0;
 268         }
 269         if (!prefixcmp(var, "man."))
 270                 return add_man_viewer_info(var, value);
 271
 272         return git_default_config(var, value, cb);
 273 }
 274
 275 static struct cmdnames main_cmds, other_cmds;
 276
 277 void list_common_cmds_help(void)
 278 {
 279         int i, longest = 0;
 280
 281         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 282                 if (longest < strlen(common_cmds[i].name))
 283                         longest = strlen(common_cmds[i].name);
 284         }
 285
 286         puts("The most commonly used git commands are:");
 287         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 288                 printf("   %s   ", common_cmds[i].name);
 289                 mput_char(' ', longest - strlen(common_cmds[i].name));
 290                 puts(common_cmds[i].help);
 291         }
 292 }
 293
 294 static int is_git_command(const char *s)
 295 {
 296         return is_in_cmdlist(&main_cmds, s) ||
 297                 is_in_cmdlist(&other_cmds, s);
 298 }
 299
 300 static const char *prepend(const char *prefix, const char *cmd)
 301 {
 302         size_t pre_len = strlen(prefix);
 303         size_t cmd_len = strlen(cmd);
 304         char *p = xmalloc(pre_len + cmd_len + 1);
 305         memcpy(p, prefix, pre_len);
 306         strcpy(p + pre_len, cmd);
 307         return p;
 308 }
 309
 310 static const char *cmd_to_page(const char *git_cmd)
 311 {
 312         if (!git_cmd)
 313                 return "git";
 314         else if (!prefixcmp(git_cmd, "git"))
 315                 return git_cmd;
 316         else if (is_git_command(git_cmd))
 317                 return prepend("git-", git_cmd);
 318         else
 319                 return prepend("git", git_cmd);
 320 }
 321
 322 static void setup_man_path(void)
 323 {
 324         struct strbuf new_path = STRBUF_INIT;
 325         const char *old_path = getenv("MANPATH");
 326
 327         /* We should always put ':' after our path. If there is no
 328          * old_path, the ':' at the end will let 'man' to try
 329          * system-wide paths after ours to find the manual page. If
 330          * there is old_path, we need ':' as delimiter. */
 331         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
 332         strbuf_addch(&new_path, ':');
 333         if (old_path)
 334                 strbuf_addstr(&new_path, old_path);
 335
 336         setenv("MANPATH", new_path.buf, 1);
 337
 338         strbuf_release(&new_path);
 339 }
 340
 341 static void exec_viewer(const char *name, const char *page)
 342 {
 343         const char *info = get_man_viewer_info(name);
 344
 345         if (!strcasecmp(name, "man"))
 346                 exec_man_man(info, page);
 347         else if (!strcasecmp(name, "woman"))
 348                 exec_woman_emacs(info, page);
 349         else if (!strcasecmp(name, "konqueror"))
 350                 exec_man_konqueror(info, page);
 351         else if (info)
 352                 exec_man_cmd(info, page);
 353         else
 354                 warning("'%s': unknown man viewer.", name);
 355 }
 356
 357 static void show_man_page(const char *git_cmd)
 358 {
 359         struct man_viewer_list *viewer;
 360         const char *page = cmd_to_page(git_cmd);
 361         const char *fallback = getenv("GIT_MAN_VIEWER");
 362
 363         setup_man_path();
 364         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 365         {
 366                 exec_viewer(viewer->name, page); /* will return when unable */
 367         }
 368         if (fallback)
 369                 exec_viewer(fallback, page);
 370         exec_viewer("man", page);
 371         die("no man viewer handled the request");
 372 }
 373
 374 static void show_info_page(const char *git_cmd)
 375 {
 376         const char *page = cmd_to_page(git_cmd);
 377         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 378         execlp("info", "info", "gitman", page, NULL);
 379 }
 380
 381 static void get_html_page_path(struct strbuf *page_path, const char *page)
 382 {
 383         struct stat st;
 384         const char *html_path = system_path(GIT_HTML_PATH);
 385
 386         /* Check that we have a git documentation directory. */
 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         strbuf_init(page_path, 0);
 392         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 393 }
 394
 395 /*
 396  * If open_html is not defined in a platform-specific way (see for
 397  * example compat/mingw.h), we use the script web--browse to display
 398  * HTML.
 399  */
 400 #ifndef open_html
 401 void open_html(const char *path)
 402 {
 403         execl_git_cmd("web--browse", "-c", "help.browser", path, NULL);
 404 }
 405 #endif
 406
 407 static void show_html_page(const char *git_cmd)
 408 {
 409         const char *page = cmd_to_page(git_cmd);
 410         struct strbuf page_path; /* it leaks but we exec bellow */
 411
 412         get_html_page_path(&page_path, page);
 413
 414         open_html(page_path.buf);
 415 }
 416
 417 int cmd_help(int argc, const char **argv, const char *prefix)
 418 {
 419         int nongit;
 420         const char *alias;
 421         load_command_list("git-", &main_cmds, &other_cmds);
 422
 423         setup_git_directory_gently(&nongit);
 424         git_config(git_help_config, NULL);
 425
 426         argc = parse_options(argc, argv, builtin_help_options,
 427                         builtin_help_usage, 0);
 428
 429         if (show_all) {
 430                 printf("usage: %s\n\n", git_usage_string);
 431                 list_commands("git commands", &main_cmds, &other_cmds);
 432                 printf("%s\n", git_more_info_string);
 433                 return 0;
 434         }
 435
 436         if (!argv[0]) {
 437                 printf("usage: %s\n\n", git_usage_string);
 438                 list_common_cmds_help();
 439                 printf("\n%s\n", git_more_info_string);
 440                 return 0;
 441         }
 442
 443         alias = alias_lookup(argv[0]);
 444         if (alias && !is_git_command(argv[0])) {
 445                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
 446                 return 0;
 447         }
 448
 449         switch (help_format) {
 450         case HELP_FORMAT_MAN:
 451                 show_man_page(argv[0]);
 452                 break;
 453         case HELP_FORMAT_INFO:
 454                 show_info_page(argv[0]);
 455                 break;
 456         case HELP_FORMAT_WEB:
 457                 show_html_page(argv[0]);
 458                 break;
 459         }
 460
 461         return 0;
 462 }