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