help.c

   1 /*
   2  * builtin-help.c
   3  *
   4  * Builtin help-related commands (help, usage, version)
   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
  13 static struct man_viewer_list {
  14         void (*exec)(const char *);
  15         struct man_viewer_list *next;
  16 } *man_viewer_list;
  17
  18 enum help_format {
  19         HELP_FORMAT_MAN,
  20         HELP_FORMAT_INFO,
  21         HELP_FORMAT_WEB,
  22 };
  23
  24 static int show_all = 0;
  25 static enum help_format help_format = HELP_FORMAT_MAN;
  26 static struct option builtin_help_options[] = {
  27         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
  28         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  29         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  30                         HELP_FORMAT_WEB),
  31         OPT_SET_INT('i', "info", &help_format, "show info page",
  32                         HELP_FORMAT_INFO),
  33         OPT_END(),
  34 };
  35
  36 static const char * const builtin_help_usage[] = {
  37         "git-help [--all] [--man|--web|--info] [command]",
  38         NULL
  39 };
  40
  41 static enum help_format parse_help_format(const char *format)
  42 {
  43         if (!strcmp(format, "man"))
  44                 return HELP_FORMAT_MAN;
  45         if (!strcmp(format, "info"))
  46                 return HELP_FORMAT_INFO;
  47         if (!strcmp(format, "web") || !strcmp(format, "html"))
  48                 return HELP_FORMAT_WEB;
  49         die("unrecognized help format '%s'", format);
  50 }
  51
  52 static int check_emacsclient_version(void)
  53 {
  54         struct strbuf buffer = STRBUF_INIT;
  55         struct child_process ec_process;
  56         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  57         int version;
  58
  59         /* emacsclient prints its version number on stderr */
  60         memset(&ec_process, 0, sizeof(ec_process));
  61         ec_process.argv = argv_ec;
  62         ec_process.err = -1;
  63         ec_process.stdout_to_stderr = 1;
  64         if (start_command(&ec_process)) {
  65                 fprintf(stderr, "Failed to start emacsclient.\n");
  66                 return -1;
  67         }
  68         strbuf_read(&buffer, ec_process.err, 20);
  69         close(ec_process.err);
  70
  71         /*
  72          * Don't bother checking return value, because "emacsclient --version"
  73          * seems to always exits with code 1.
  74          */
  75         finish_command(&ec_process);
  76
  77         if (prefixcmp(buffer.buf, "emacsclient")) {
  78                 fprintf(stderr, "Failed to parse emacsclient version.\n");
  79                 strbuf_release(&buffer);
  80                 return -1;
  81         }
  82
  83         strbuf_remove(&buffer, 0, strlen("emacsclient"));
  84         version = atoi(buffer.buf);
  85
  86         if (version < 22) {
  87                 fprintf(stderr,
  88                         "emacsclient version '%d' too old (< 22).\n",
  89                         version);
  90                 strbuf_release(&buffer);
  91                 return -1;
  92         }
  93
  94         strbuf_release(&buffer);
  95         return 0;
  96 }
  97
  98 static void exec_woman_emacs(const char *page)
  99 {
 100         if (!check_emacsclient_version()) {
 101                 /* This works only with emacsclient version >= 22. */
 102                 struct strbuf man_page = STRBUF_INIT;
 103                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 104                 execlp("emacsclient", "emacsclient", "-e", man_page.buf, NULL);
 105         }
 106 }
 107
 108 static void exec_man_konqueror(const char *page)
 109 {
 110         const char *display = getenv("DISPLAY");
 111         if (display && *display) {
 112                 struct strbuf man_page = STRBUF_INIT;
 113                 strbuf_addf(&man_page, "man:%s(1)", page);
 114                 execlp("kfmclient", "kfmclient", "newTab", man_page.buf, NULL);
 115         }
 116 }
 117
 118 static void exec_man_man(const char *page)
 119 {
 120         execlp("man", "man", page, NULL);
 121 }
 122
 123 static void do_add_man_viewer(void (*exec)(const char *))
 124 {
 125         struct man_viewer_list **p = &man_viewer_list;
 126
 127         while (*p)
 128                 p = &((*p)->next);
 129         *p = xmalloc(sizeof(**p));
 130         (*p)->next = NULL;
 131         (*p)->exec = exec;
 132 }
 133
 134 static int add_man_viewer(const char *value)
 135 {
 136         if (!strcasecmp(value, "man"))
 137                 do_add_man_viewer(exec_man_man);
 138         else if (!strcasecmp(value, "woman"))
 139                 do_add_man_viewer(exec_woman_emacs);
 140         else if (!strcasecmp(value, "konqueror"))
 141                 do_add_man_viewer(exec_man_konqueror);
 142         else
 143                 warning("'%s': unsupported man viewer.", value);
 144
 145         return 0;
 146 }
 147
 148 static int git_help_config(const char *var, const char *value)
 149 {
 150         if (!strcmp(var, "help.format")) {
 151                 if (!value)
 152                         return config_error_nonbool(var);
 153                 help_format = parse_help_format(value);
 154                 return 0;
 155         }
 156         if (!strcmp(var, "man.viewer")) {
 157                 if (!value)
 158                         return config_error_nonbool(var);
 159                 return add_man_viewer(value);
 160         }
 161         return git_default_config(var, value);
 162 }
 163
 164 /* most GUI terminals set COLUMNS (although some don't export it) */
 165 static int term_columns(void)
 166 {
 167         char *col_string = getenv("COLUMNS");
 168         int n_cols;
 169
 170         if (col_string && (n_cols = atoi(col_string)) > 0)
 171                 return n_cols;
 172
 173 #ifdef TIOCGWINSZ
 174         {
 175                 struct winsize ws;
 176                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
 177                         if (ws.ws_col)
 178                                 return ws.ws_col;
 179                 }
 180         }
 181 #endif
 182
 183         return 80;
 184 }
 185
 186 static inline void mput_char(char c, unsigned int num)
 187 {
 188         while(num--)
 189                 putchar(c);
 190 }
 191
 192 static struct cmdnames {
 193         int alloc;
 194         int cnt;
 195         struct cmdname {
 196                 size_t len;
 197                 char name[1];
 198         } **names;
 199 } main_cmds, other_cmds;
 200
 201 static void add_cmdname(struct cmdnames *cmds, const char *name, int len)
 202 {
 203         struct cmdname *ent = xmalloc(sizeof(*ent) + len);
 204
 205         ent->len = len;
 206         memcpy(ent->name, name, len);
 207         ent->name[len] = 0;
 208
 209         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
 210         cmds->names[cmds->cnt++] = ent;
 211 }
 212
 213 static int cmdname_compare(const void *a_, const void *b_)
 214 {
 215         struct cmdname *a = *(struct cmdname **)a_;
 216         struct cmdname *b = *(struct cmdname **)b_;
 217         return strcmp(a->name, b->name);
 218 }
 219
 220 static void uniq(struct cmdnames *cmds)
 221 {
 222         int i, j;
 223
 224         if (!cmds->cnt)
 225                 return;
 226
 227         for (i = j = 1; i < cmds->cnt; i++)
 228                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
 229                         cmds->names[j++] = cmds->names[i];
 230
 231         cmds->cnt = j;
 232 }
 233
 234 static void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
 235 {
 236         int ci, cj, ei;
 237         int cmp;
 238
 239         ci = cj = ei = 0;
 240         while (ci < cmds->cnt && ei < excludes->cnt) {
 241                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
 242                 if (cmp < 0)
 243                         cmds->names[cj++] = cmds->names[ci++];
 244                 else if (cmp == 0)
 245                         ci++, ei++;
 246                 else if (cmp > 0)
 247                         ei++;
 248         }
 249
 250         while (ci < cmds->cnt)
 251                 cmds->names[cj++] = cmds->names[ci++];
 252
 253         cmds->cnt = cj;
 254 }
 255
 256 static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 257 {
 258         int cols = 1, rows;
 259         int space = longest + 1; /* min 1 SP between words */
 260         int max_cols = term_columns() - 1; /* don't print *on* the edge */
 261         int i, j;
 262
 263         if (space < max_cols)
 264                 cols = max_cols / space;
 265         rows = (cmds->cnt + cols - 1) / cols;
 266
 267         for (i = 0; i < rows; i++) {
 268                 printf("  ");
 269
 270                 for (j = 0; j < cols; j++) {
 271                         int n = j * rows + i;
 272                         int size = space;
 273                         if (n >= cmds->cnt)
 274                                 break;
 275                         if (j == cols-1 || n + rows >= cmds->cnt)
 276                                 size = 1;
 277                         printf("%-*s", size, cmds->names[n]->name);
 278                 }
 279                 putchar('\n');
 280         }
 281 }
 282
 283 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 284                                          const char *path)
 285 {
 286         unsigned int longest = 0;
 287         const char *prefix = "git-";
 288         int prefix_len = strlen(prefix);
 289         DIR *dir = opendir(path);
 290         struct dirent *de;
 291
 292         if (!dir || chdir(path))
 293                 return 0;
 294
 295         while ((de = readdir(dir)) != NULL) {
 296                 struct stat st;
 297                 int entlen;
 298
 299                 if (prefixcmp(de->d_name, prefix))
 300                         continue;
 301
 302                 if (stat(de->d_name, &st) || /* stat, not lstat */
 303                     !S_ISREG(st.st_mode) ||
 304                     !(st.st_mode & S_IXUSR))
 305                         continue;
 306
 307                 entlen = strlen(de->d_name) - prefix_len;
 308                 if (has_extension(de->d_name, ".exe"))
 309                         entlen -= 4;
 310
 311                 if (longest < entlen)
 312                         longest = entlen;
 313
 314                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 315         }
 316         closedir(dir);
 317
 318         return longest;
 319 }
 320
 321 static unsigned int load_command_list(void)
 322 {
 323         unsigned int longest = 0;
 324         unsigned int len;
 325         const char *env_path = getenv("PATH");
 326         char *paths, *path, *colon;
 327         const char *exec_path = git_exec_path();
 328
 329         if (exec_path)
 330                 longest = list_commands_in_dir(&main_cmds, exec_path);
 331
 332         if (!env_path) {
 333                 fprintf(stderr, "PATH not set\n");
 334                 exit(1);
 335         }
 336
 337         path = paths = xstrdup(env_path);
 338         while (1) {
 339                 if ((colon = strchr(path, ':')))
 340                         *colon = 0;
 341
 342                 len = list_commands_in_dir(&other_cmds, path);
 343                 if (len > longest)
 344                         longest = len;
 345
 346                 if (!colon)
 347                         break;
 348                 path = colon + 1;
 349         }
 350         free(paths);
 351
 352         qsort(main_cmds.names, main_cmds.cnt,
 353               sizeof(*main_cmds.names), cmdname_compare);
 354         uniq(&main_cmds);
 355
 356         qsort(other_cmds.names, other_cmds.cnt,
 357               sizeof(*other_cmds.names), cmdname_compare);
 358         uniq(&other_cmds);
 359         exclude_cmds(&other_cmds, &main_cmds);
 360
 361         return longest;
 362 }
 363
 364 static void list_commands(void)
 365 {
 366         unsigned int longest = load_command_list();
 367         const char *exec_path = git_exec_path();
 368
 369         if (main_cmds.cnt) {
 370                 printf("available git commands in '%s'\n", exec_path);
 371                 printf("----------------------------");
 372                 mput_char('-', strlen(exec_path));
 373                 putchar('\n');
 374                 pretty_print_string_list(&main_cmds, longest);
 375                 putchar('\n');
 376         }
 377
 378         if (other_cmds.cnt) {
 379                 printf("git commands available from elsewhere on your $PATH\n");
 380                 printf("---------------------------------------------------\n");
 381                 pretty_print_string_list(&other_cmds, longest);
 382                 putchar('\n');
 383         }
 384 }
 385
 386 void list_common_cmds_help(void)
 387 {
 388         int i, longest = 0;
 389
 390         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 391                 if (longest < strlen(common_cmds[i].name))
 392                         longest = strlen(common_cmds[i].name);
 393         }
 394
 395         puts("The most commonly used git commands are:");
 396         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 397                 printf("   %s   ", common_cmds[i].name);
 398                 mput_char(' ', longest - strlen(common_cmds[i].name));
 399                 puts(common_cmds[i].help);
 400         }
 401 }
 402
 403 static int is_in_cmdlist(struct cmdnames *c, const char *s)
 404 {
 405         int i;
 406         for (i = 0; i < c->cnt; i++)
 407                 if (!strcmp(s, c->names[i]->name))
 408                         return 1;
 409         return 0;
 410 }
 411
 412 static int is_git_command(const char *s)
 413 {
 414         load_command_list();
 415         return is_in_cmdlist(&main_cmds, s) ||
 416                 is_in_cmdlist(&other_cmds, s);
 417 }
 418
 419 static const char *cmd_to_page(const char *git_cmd)
 420 {
 421         if (!git_cmd)
 422                 return "git";
 423         else if (!prefixcmp(git_cmd, "git"))
 424                 return git_cmd;
 425         else {
 426                 int page_len = strlen(git_cmd) + 4;
 427                 char *p = xmalloc(page_len + 1);
 428                 strcpy(p, "git-");
 429                 strcpy(p + 4, git_cmd);
 430                 p[page_len] = 0;
 431                 return p;
 432         }
 433 }
 434
 435 static void setup_man_path(void)
 436 {
 437         struct strbuf new_path;
 438         const char *old_path = getenv("MANPATH");
 439
 440         strbuf_init(&new_path, 0);
 441
 442         /* We should always put ':' after our path. If there is no
 443          * old_path, the ':' at the end will let 'man' to try
 444          * system-wide paths after ours to find the manual page. If
 445          * there is old_path, we need ':' as delimiter. */
 446         strbuf_addstr(&new_path, GIT_MAN_PATH);
 447         strbuf_addch(&new_path, ':');
 448         if (old_path)
 449                 strbuf_addstr(&new_path, old_path);
 450
 451         setenv("MANPATH", new_path.buf, 1);
 452
 453         strbuf_release(&new_path);
 454 }
 455
 456 static void show_man_page(const char *git_cmd)
 457 {
 458         struct man_viewer_list *viewer;
 459         const char *page = cmd_to_page(git_cmd);
 460
 461         setup_man_path();
 462         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 463         {
 464                 viewer->exec(page); /* will return when unable */
 465         }
 466         exec_man_man(page);
 467         die("no man viewer handled the request");
 468 }
 469
 470 static void show_info_page(const char *git_cmd)
 471 {
 472         const char *page = cmd_to_page(git_cmd);
 473         setenv("INFOPATH", GIT_INFO_PATH, 1);
 474         execlp("info", "info", "gitman", page, NULL);
 475 }
 476
 477 static void get_html_page_path(struct strbuf *page_path, const char *page)
 478 {
 479         struct stat st;
 480
 481         /* Check that we have a git documentation directory. */
 482         if (stat(GIT_HTML_PATH "/git.html", &st) || !S_ISREG(st.st_mode))
 483                 die("'%s': not a documentation directory.", GIT_HTML_PATH);
 484
 485         strbuf_init(page_path, 0);
 486         strbuf_addf(page_path, GIT_HTML_PATH "/%s.html", page);
 487 }
 488
 489 static void show_html_page(const char *git_cmd)
 490 {
 491         const char *page = cmd_to_page(git_cmd);
 492         struct strbuf page_path; /* it leaks but we exec bellow */
 493
 494         get_html_page_path(&page_path, page);
 495
 496         execl_git_cmd("web--browse", "-c", "help.browser", page_path.buf, NULL);
 497 }
 498
 499 void help_unknown_cmd(const char *cmd)
 500 {
 501         fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
 502         exit(1);
 503 }
 504
 505 int cmd_version(int argc, const char **argv, const char *prefix)
 506 {
 507         printf("git version %s\n", git_version_string);
 508         return 0;
 509 }
 510
 511 int cmd_help(int argc, const char **argv, const char *prefix)
 512 {
 513         int nongit;
 514         const char *alias;
 515
 516         setup_git_directory_gently(&nongit);
 517         git_config(git_help_config);
 518
 519         argc = parse_options(argc, argv, builtin_help_options,
 520                         builtin_help_usage, 0);
 521
 522         if (show_all) {
 523                 printf("usage: %s\n\n", git_usage_string);
 524                 list_commands();
 525                 return 0;
 526         }
 527
 528         if (!argv[0]) {
 529                 printf("usage: %s\n\n", git_usage_string);
 530                 list_common_cmds_help();
 531                 return 0;
 532         }
 533
 534         alias = alias_lookup(argv[0]);
 535         if (alias && !is_git_command(argv[0])) {
 536                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
 537                 return 0;
 538         }
 539
 540         switch (help_format) {
 541         case HELP_FORMAT_MAN:
 542                 show_man_page(argv[0]);
 543                 break;
 544         case HELP_FORMAT_INFO:
 545                 show_info_page(argv[0]);
 546                 break;
 547         case HELP_FORMAT_WEB:
 548                 show_html_page(argv[0]);
 549                 break;
 550         }
 551
 552         return 0;
 553 }