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 };
  34
  35 static const char * const builtin_help_usage[] = {
  36         "git-help [--all] [--man|--web|--info] [command]",
  37         NULL
  38 };
  39
  40 static enum help_format parse_help_format(const char *format)
  41 {
  42         if (!strcmp(format, "man"))
  43                 return HELP_FORMAT_MAN;
  44         if (!strcmp(format, "info"))
  45                 return HELP_FORMAT_INFO;
  46         if (!strcmp(format, "web") || !strcmp(format, "html"))
  47                 return HELP_FORMAT_WEB;
  48         die("unrecognized help format '%s'", format);
  49 }
  50
  51 static int check_emacsclient_version(void)
  52 {
  53         struct strbuf buffer = STRBUF_INIT;
  54         struct child_process ec_process;
  55         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  56         int version;
  57
  58         /* emacsclient prints its version number on stderr */
  59         memset(&ec_process, 0, sizeof(ec_process));
  60         ec_process.argv = argv_ec;
  61         ec_process.err = -1;
  62         ec_process.stdout_to_stderr = 1;
  63         if (start_command(&ec_process)) {
  64                 fprintf(stderr, "Failed to start emacsclient.\n");
  65                 return -1;
  66         }
  67         strbuf_read(&buffer, ec_process.err, 20);
  68         close(ec_process.err);
  69
  70         /*
  71          * Don't bother checking return value, because "emacsclient --version"
  72          * seems to always exits with code 1.
  73          */
  74         finish_command(&ec_process);
  75
  76         if (prefixcmp(buffer.buf, "emacsclient")) {
  77                 fprintf(stderr, "Failed to parse emacsclient version.\n");
  78                 strbuf_release(&buffer);
  79                 return -1;
  80         }
  81
  82         strbuf_remove(&buffer, 0, strlen("emacsclient"));
  83         version = atoi(buffer.buf);
  84
  85         if (version < 22) {
  86                 fprintf(stderr,
  87                         "emacsclient version '%d' too old (< 22).\n",
  88                         version);
  89                 strbuf_release(&buffer);
  90                 return -1;
  91         }
  92
  93         strbuf_release(&buffer);
  94         return 0;
  95 }
  96
  97 static void exec_woman_emacs(const char *page)
  98 {
  99         if (!check_emacsclient_version()) {
 100                 /* This works only with emacsclient version >= 22. */
 101                 struct strbuf man_page = STRBUF_INIT;
 102                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 103                 execlp("emacsclient", "emacsclient", "-e", man_page.buf, NULL);
 104         }
 105 }
 106
 107 static void exec_man_konqueror(const char *page)
 108 {
 109         const char *display = getenv("DISPLAY");
 110         if (display && *display) {
 111                 struct strbuf man_page = STRBUF_INIT;
 112                 strbuf_addf(&man_page, "man:%s(1)", page);
 113                 execlp("kfmclient", "kfmclient", "newTab", man_page.buf, NULL);
 114         }
 115 }
 116
 117 static void exec_man_man(const char *page)
 118 {
 119         execlp("man", "man", page, NULL);
 120 }
 121
 122 static void do_add_man_viewer(void (*exec)(const char *))
 123 {
 124         struct man_viewer_list **p = &man_viewer_list;
 125
 126         while (*p)
 127                 p = &((*p)->next);
 128         *p = xmalloc(sizeof(**p));
 129         (*p)->next = NULL;
 130         (*p)->exec = exec;
 131 }
 132
 133 static int add_man_viewer(const char *value)
 134 {
 135         if (!strcasecmp(value, "man"))
 136                 do_add_man_viewer(exec_man_man);
 137         else if (!strcasecmp(value, "woman"))
 138                 do_add_man_viewer(exec_woman_emacs);
 139         else if (!strcasecmp(value, "konqueror"))
 140                 do_add_man_viewer(exec_man_konqueror);
 141         else
 142                 warning("'%s': unsupported man viewer.", value);
 143
 144         return 0;
 145 }
 146
 147 static int git_help_config(const char *var, const char *value)
 148 {
 149         if (!strcmp(var, "help.format")) {
 150                 if (!value)
 151                         return config_error_nonbool(var);
 152                 help_format = parse_help_format(value);
 153                 return 0;
 154         }
 155         if (!strcmp(var, "man.viewer")) {
 156                 if (!value)
 157                         return config_error_nonbool(var);
 158                 return add_man_viewer(value);
 159         }
 160         return git_default_config(var, value);
 161 }
 162
 163 /* most GUI terminals set COLUMNS (although some don't export it) */
 164 static int term_columns(void)
 165 {
 166         char *col_string = getenv("COLUMNS");
 167         int n_cols;
 168
 169         if (col_string && (n_cols = atoi(col_string)) > 0)
 170                 return n_cols;
 171
 172 #ifdef TIOCGWINSZ
 173         {
 174                 struct winsize ws;
 175                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
 176                         if (ws.ws_col)
 177                                 return ws.ws_col;
 178                 }
 179         }
 180 #endif
 181
 182         return 80;
 183 }
 184
 185 static inline void mput_char(char c, unsigned int num)
 186 {
 187         while(num--)
 188                 putchar(c);
 189 }
 190
 191 static struct cmdnames {
 192         int alloc;
 193         int cnt;
 194         struct cmdname {
 195                 size_t len;
 196                 char name[1];
 197         } **names;
 198 } main_cmds, other_cmds;
 199
 200 static void add_cmdname(struct cmdnames *cmds, const char *name, int len)
 201 {
 202         struct cmdname *ent = xmalloc(sizeof(*ent) + len);
 203
 204         ent->len = len;
 205         memcpy(ent->name, name, len);
 206         ent->name[len] = 0;
 207
 208         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
 209         cmds->names[cmds->cnt++] = ent;
 210 }
 211
 212 static int cmdname_compare(const void *a_, const void *b_)
 213 {
 214         struct cmdname *a = *(struct cmdname **)a_;
 215         struct cmdname *b = *(struct cmdname **)b_;
 216         return strcmp(a->name, b->name);
 217 }
 218
 219 static void uniq(struct cmdnames *cmds)
 220 {
 221         int i, j;
 222
 223         if (!cmds->cnt)
 224                 return;
 225
 226         for (i = j = 1; i < cmds->cnt; i++)
 227                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
 228                         cmds->names[j++] = cmds->names[i];
 229
 230         cmds->cnt = j;
 231 }
 232
 233 static void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
 234 {
 235         int ci, cj, ei;
 236         int cmp;
 237
 238         ci = cj = ei = 0;
 239         while (ci < cmds->cnt && ei < excludes->cnt) {
 240                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
 241                 if (cmp < 0)
 242                         cmds->names[cj++] = cmds->names[ci++];
 243                 else if (cmp == 0)
 244                         ci++, ei++;
 245                 else if (cmp > 0)
 246                         ei++;
 247         }
 248
 249         while (ci < cmds->cnt)
 250                 cmds->names[cj++] = cmds->names[ci++];
 251
 252         cmds->cnt = cj;
 253 }
 254
 255 static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 256 {
 257         int cols = 1, rows;
 258         int space = longest + 1; /* min 1 SP between words */
 259         int max_cols = term_columns() - 1; /* don't print *on* the edge */
 260         int i, j;
 261
 262         if (space < max_cols)
 263                 cols = max_cols / space;
 264         rows = (cmds->cnt + cols - 1) / cols;
 265
 266         for (i = 0; i < rows; i++) {
 267                 printf("  ");
 268
 269                 for (j = 0; j < cols; j++) {
 270                         int n = j * rows + i;
 271                         int size = space;
 272                         if (n >= cmds->cnt)
 273                                 break;
 274                         if (j == cols-1 || n + rows >= cmds->cnt)
 275                                 size = 1;
 276                         printf("%-*s", size, cmds->names[n]->name);
 277                 }
 278                 putchar('\n');
 279         }
 280 }
 281
 282 static int is_executable(const char *name)
 283 {
 284         struct stat st;
 285
 286         if (stat(name, &st) || /* stat, not lstat */
 287             !S_ISREG(st.st_mode))
 288                 return 0;
 289
 290 #ifdef __MINGW32__
 291         /* cannot trust the executable bit, peek into the file instead */
 292         char buf[3] = { 0 };
 293         int n;
 294         int fd = open(name, O_RDONLY);
 295         st.st_mode &= ~S_IXUSR;
 296         if (fd >= 0) {
 297                 n = read(fd, buf, 2);
 298                 if (n == 2)
 299                         /* DOS executables start with "MZ" */
 300                         if (!strcmp(buf, "#!") || !strcmp(buf, "MZ"))
 301                                 st.st_mode |= S_IXUSR;
 302                 close(fd);
 303         }
 304 #endif
 305         return st.st_mode & S_IXUSR;
 306 }
 307
 308 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 309                                          const char *path)
 310 {
 311         unsigned int longest = 0;
 312         const char *prefix = "git-";
 313         int prefix_len = strlen(prefix);
 314         DIR *dir = opendir(path);
 315         struct dirent *de;
 316
 317         if (!dir || chdir(path))
 318                 return 0;
 319
 320         while ((de = readdir(dir)) != NULL) {
 321                 int entlen;
 322
 323                 if (prefixcmp(de->d_name, prefix))
 324                         continue;
 325
 326                 if (!is_executable(de->d_name))
 327                         continue;
 328
 329                 entlen = strlen(de->d_name) - prefix_len;
 330                 if (has_extension(de->d_name, ".exe"))
 331                         entlen -= 4;
 332
 333                 if (longest < entlen)
 334                         longest = entlen;
 335
 336                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 337         }
 338         closedir(dir);
 339
 340         return longest;
 341 }
 342
 343 static unsigned int load_command_list(void)
 344 {
 345         unsigned int longest = 0;
 346         unsigned int len;
 347         const char *env_path = getenv("PATH");
 348         char *paths, *path, *colon;
 349         const char *exec_path = git_exec_path();
 350
 351         if (exec_path)
 352                 longest = list_commands_in_dir(&main_cmds, exec_path);
 353
 354         if (!env_path) {
 355                 fprintf(stderr, "PATH not set\n");
 356                 exit(1);
 357         }
 358
 359         path = paths = xstrdup(env_path);
 360         while (1) {
 361                 if ((colon = strchr(path, PATH_SEP)))
 362                         *colon = 0;
 363
 364                 len = list_commands_in_dir(&other_cmds, path);
 365                 if (len > longest)
 366                         longest = len;
 367
 368                 if (!colon)
 369                         break;
 370                 path = colon + 1;
 371         }
 372         free(paths);
 373
 374         qsort(main_cmds.names, main_cmds.cnt,
 375               sizeof(*main_cmds.names), cmdname_compare);
 376         uniq(&main_cmds);
 377
 378         qsort(other_cmds.names, other_cmds.cnt,
 379               sizeof(*other_cmds.names), cmdname_compare);
 380         uniq(&other_cmds);
 381         exclude_cmds(&other_cmds, &main_cmds);
 382
 383         return longest;
 384 }
 385
 386 static void list_commands(void)
 387 {
 388         unsigned int longest = load_command_list();
 389         const char *exec_path = git_exec_path();
 390
 391         if (main_cmds.cnt) {
 392                 printf("available git commands in '%s'\n", exec_path);
 393                 printf("----------------------------");
 394                 mput_char('-', strlen(exec_path));
 395                 putchar('\n');
 396                 pretty_print_string_list(&main_cmds, longest);
 397                 putchar('\n');
 398         }
 399
 400         if (other_cmds.cnt) {
 401                 printf("git commands available from elsewhere on your $PATH\n");
 402                 printf("---------------------------------------------------\n");
 403                 pretty_print_string_list(&other_cmds, longest);
 404                 putchar('\n');
 405         }
 406 }
 407
 408 void list_common_cmds_help(void)
 409 {
 410         int i, longest = 0;
 411
 412         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 413                 if (longest < strlen(common_cmds[i].name))
 414                         longest = strlen(common_cmds[i].name);
 415         }
 416
 417         puts("The most commonly used git commands are:");
 418         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 419                 printf("   %s   ", common_cmds[i].name);
 420                 mput_char(' ', longest - strlen(common_cmds[i].name));
 421                 puts(common_cmds[i].help);
 422         }
 423 }
 424
 425 static int is_in_cmdlist(struct cmdnames *c, const char *s)
 426 {
 427         int i;
 428         for (i = 0; i < c->cnt; i++)
 429                 if (!strcmp(s, c->names[i]->name))
 430                         return 1;
 431         return 0;
 432 }
 433
 434 static int is_git_command(const char *s)
 435 {
 436         load_command_list();
 437         return is_in_cmdlist(&main_cmds, s) ||
 438                 is_in_cmdlist(&other_cmds, s);
 439 }
 440
 441 static const char *cmd_to_page(const char *git_cmd)
 442 {
 443         if (!git_cmd)
 444                 return "git";
 445         else if (!prefixcmp(git_cmd, "git"))
 446                 return git_cmd;
 447         else {
 448                 int page_len = strlen(git_cmd) + 4;
 449                 char *p = xmalloc(page_len + 1);
 450                 strcpy(p, "git-");
 451                 strcpy(p + 4, git_cmd);
 452                 p[page_len] = 0;
 453                 return p;
 454         }
 455 }
 456
 457 static void setup_man_path(void)
 458 {
 459         struct strbuf new_path;
 460         const char *old_path = getenv("MANPATH");
 461
 462         strbuf_init(&new_path, 0);
 463
 464         /* We should always put ':' after our path. If there is no
 465          * old_path, the ':' at the end will let 'man' to try
 466          * system-wide paths after ours to find the manual page. If
 467          * there is old_path, we need ':' as delimiter. */
 468         strbuf_addstr(&new_path, GIT_MAN_PATH);
 469         strbuf_addch(&new_path, ':');
 470         if (old_path)
 471                 strbuf_addstr(&new_path, old_path);
 472
 473         setenv("MANPATH", new_path.buf, 1);
 474
 475         strbuf_release(&new_path);
 476 }
 477
 478 static void show_man_page(const char *git_cmd)
 479 {
 480         struct man_viewer_list *viewer;
 481         const char *page = cmd_to_page(git_cmd);
 482
 483         setup_man_path();
 484         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 485         {
 486                 viewer->exec(page); /* will return when unable */
 487         }
 488         exec_man_man(page);
 489         die("no man viewer handled the request");
 490 }
 491
 492 static void show_info_page(const char *git_cmd)
 493 {
 494         const char *page = cmd_to_page(git_cmd);
 495         setenv("INFOPATH", GIT_INFO_PATH, 1);
 496         execlp("info", "info", "gitman", page, NULL);
 497 }
 498
 499 static void get_html_page_path(struct strbuf *page_path, const char *page)
 500 {
 501         struct stat st;
 502
 503         /* Check that we have a git documentation directory. */
 504         if (stat(GIT_HTML_PATH "/git.html", &st) || !S_ISREG(st.st_mode))
 505                 die("'%s': not a documentation directory.", GIT_HTML_PATH);
 506
 507         strbuf_init(page_path, 0);
 508         strbuf_addf(page_path, GIT_HTML_PATH "/%s.html", page);
 509 }
 510
 511 static void show_html_page(const char *git_cmd)
 512 {
 513         const char *page = cmd_to_page(git_cmd);
 514         struct strbuf page_path; /* it leaks but we exec bellow */
 515
 516         get_html_page_path(&page_path, page);
 517
 518         execl_git_cmd("web--browse", "-c", "help.browser", page_path.buf, NULL);
 519 }
 520
 521 void help_unknown_cmd(const char *cmd)
 522 {
 523         fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
 524         exit(1);
 525 }
 526
 527 int cmd_version(int argc, const char **argv, const char *prefix)
 528 {
 529         printf("git version %s\n", git_version_string);
 530         return 0;
 531 }
 532
 533 int cmd_help(int argc, const char **argv, const char *prefix)
 534 {
 535         int nongit;
 536         const char *alias;
 537
 538         setup_git_directory_gently(&nongit);
 539         git_config(git_help_config);
 540
 541         argc = parse_options(argc, argv, builtin_help_options,
 542                         builtin_help_usage, 0);
 543
 544         if (show_all) {
 545                 printf("usage: %s\n\n", git_usage_string);
 546                 list_commands();
 547                 return 0;
 548         }
 549
 550         if (!argv[0]) {
 551                 printf("usage: %s\n\n", git_usage_string);
 552                 list_common_cmds_help();
 553                 return 0;
 554         }
 555
 556         alias = alias_lookup(argv[0]);
 557         if (alias && !is_git_command(argv[0])) {
 558                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
 559                 return 0;
 560         }
 561
 562         switch (help_format) {
 563         case HELP_FORMAT_MAN:
 564                 show_man_page(argv[0]);
 565                 break;
 566         case HELP_FORMAT_INFO:
 567                 show_info_page(argv[0]);
 568                 break;
 569         case HELP_FORMAT_WEB:
 570                 show_html_page(argv[0]);
 571                 break;
 572         }
 573
 574         return 0;
 575 }