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         struct man_viewer_list *next;
  15         char name[FLEX_ARRAY];
  16 } *man_viewer_list;
  17
  18 static struct man_viewer_info_list {
  19         struct man_viewer_info_list *next;
  20         const char *info;
  21         char name[FLEX_ARRAY];
  22 } *man_viewer_info_list;
  23
  24 enum help_format {
  25         HELP_FORMAT_MAN,
  26         HELP_FORMAT_INFO,
  27         HELP_FORMAT_WEB,
  28 };
  29
  30 static int show_all = 0;
  31 static enum help_format help_format = HELP_FORMAT_MAN;
  32 static struct option builtin_help_options[] = {
  33         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
  34         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  35         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  36                         HELP_FORMAT_WEB),
  37         OPT_SET_INT('i', "info", &help_format, "show info page",
  38                         HELP_FORMAT_INFO),
  39         OPT_END(),
  40 };
  41
  42 static const char * const builtin_help_usage[] = {
  43         "git-help [--all] [--man|--web|--info] [command]",
  44         NULL
  45 };
  46
  47 static enum help_format parse_help_format(const char *format)
  48 {
  49         if (!strcmp(format, "man"))
  50                 return HELP_FORMAT_MAN;
  51         if (!strcmp(format, "info"))
  52                 return HELP_FORMAT_INFO;
  53         if (!strcmp(format, "web") || !strcmp(format, "html"))
  54                 return HELP_FORMAT_WEB;
  55         die("unrecognized help format '%s'", format);
  56 }
  57
  58 static const char *get_man_viewer_info(const char *name)
  59 {
  60         struct man_viewer_info_list *viewer;
  61
  62         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  63         {
  64                 if (!strcasecmp(name, viewer->name))
  65                         return viewer->info;
  66         }
  67         return NULL;
  68 }
  69
  70 static int check_emacsclient_version(void)
  71 {
  72         struct strbuf buffer = STRBUF_INIT;
  73         struct child_process ec_process;
  74         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  75         int version;
  76
  77         /* emacsclient prints its version number on stderr */
  78         memset(&ec_process, 0, sizeof(ec_process));
  79         ec_process.argv = argv_ec;
  80         ec_process.err = -1;
  81         ec_process.stdout_to_stderr = 1;
  82         if (start_command(&ec_process)) {
  83                 fprintf(stderr, "Failed to start emacsclient.\n");
  84                 return -1;
  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                 fprintf(stderr, "Failed to parse emacsclient version.\n");
  97                 strbuf_release(&buffer);
  98                 return -1;
  99         }
 100
 101         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 102         version = atoi(buffer.buf);
 103
 104         if (version < 22) {
 105                 fprintf(stderr,
 106                         "emacsclient version '%d' too old (< 22).\n",
 107                         version);
 108                 strbuf_release(&buffer);
 109                 return -1;
 110         }
 111
 112         strbuf_release(&buffer);
 113         return 0;
 114 }
 115
 116 static void exec_woman_emacs(const char* path, const char *page)
 117 {
 118         if (!check_emacsclient_version()) {
 119                 /* This works only with emacsclient version >= 22. */
 120                 struct strbuf man_page = STRBUF_INIT;
 121
 122                 if (!path)
 123                         path = "emacsclient";
 124                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 125                 execlp(path, "emacsclient", "-e", man_page.buf, NULL);
 126                 warning("failed to exec '%s': %s", path, strerror(errno));
 127         }
 128 }
 129
 130 static void exec_man_konqueror(const char* path, const char *page)
 131 {
 132         const char *display = getenv("DISPLAY");
 133         if (display && *display) {
 134                 struct strbuf man_page = STRBUF_INIT;
 135                 const char *filename = "kfmclient";
 136
 137                 /* It's simpler to launch konqueror using kfmclient. */
 138                 if (path) {
 139                         const char *file = strrchr(path, '/');
 140                         if (file && !strcmp(file + 1, "konqueror")) {
 141                                 char *new = xstrdup(path);
 142                                 char *dest = strrchr(new, '/');
 143
 144                                 /* strlen("konqueror") == strlen("kfmclient") */
 145                                 strcpy(dest + 1, "kfmclient");
 146                                 path = new;
 147                         }
 148                         if (file)
 149                                 filename = file;
 150                 } else
 151                         path = "kfmclient";
 152                 strbuf_addf(&man_page, "man:%s(1)", page);
 153                 execlp(path, filename, "newTab", man_page.buf, NULL);
 154                 warning("failed to exec '%s': %s", path, strerror(errno));
 155         }
 156 }
 157
 158 static void exec_man_man(const char* path, const char *page)
 159 {
 160         if (!path)
 161                 path = "man";
 162         execlp(path, "man", page, NULL);
 163         warning("failed to exec '%s': %s", path, strerror(errno));
 164 }
 165
 166 static void do_add_man_viewer(const char *name)
 167 {
 168         struct man_viewer_list **p = &man_viewer_list;
 169         size_t len = strlen(name);
 170
 171         while (*p)
 172                 p = &((*p)->next);
 173         *p = xcalloc(1, (sizeof(**p) + len + 1));
 174         strncpy((*p)->name, name, len);
 175 }
 176
 177 static int supported_man_viewer(const char *name, size_t len)
 178 {
 179         return (!strncasecmp("man", name, len) ||
 180                 !strncasecmp("woman", name, len) ||
 181                 !strncasecmp("konqueror", name, len));
 182 }
 183
 184 static int add_man_viewer(const char *value)
 185 {
 186         if (supported_man_viewer(value, strlen(value)))
 187                 do_add_man_viewer(value);
 188         else
 189                 warning("'%s': unsupported man viewer.", value);
 190
 191         return 0;
 192 }
 193
 194 static void do_add_man_viewer_info(const char *name,
 195                                    size_t len,
 196                                    const char *value)
 197 {
 198         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 199
 200         strncpy(new->name, name, len);
 201         new->info = xstrdup(value);
 202         new->next = man_viewer_info_list;
 203         man_viewer_info_list = new;
 204 }
 205
 206 static int add_man_viewer_path(const char *name,
 207                                size_t len,
 208                                const char *value)
 209 {
 210         if (supported_man_viewer(name, len))
 211                 do_add_man_viewer_info(name, len, value);
 212         else
 213                 warning("'%s': path for unsupported man viewer.", name);
 214
 215         return 0;
 216 }
 217
 218 static int add_man_viewer_info(const char *var, const char *value)
 219 {
 220         const char *name = var + 4;
 221         const char *subkey = strrchr(name, '.');
 222
 223         if (!subkey)
 224                 return error("Config with no key for man viewer: %s", name);
 225
 226         if (!strcmp(subkey, ".path")) {
 227                 if (!value)
 228                         return config_error_nonbool(var);
 229                 return add_man_viewer_path(name, subkey - name, value);
 230         }
 231
 232         warning("'%s': unsupported man viewer sub key.", subkey);
 233         return 0;
 234 }
 235
 236 static int git_help_config(const char *var, const char *value)
 237 {
 238         if (!strcmp(var, "help.format")) {
 239                 if (!value)
 240                         return config_error_nonbool(var);
 241                 help_format = parse_help_format(value);
 242                 return 0;
 243         }
 244         if (!strcmp(var, "man.viewer")) {
 245                 if (!value)
 246                         return config_error_nonbool(var);
 247                 return add_man_viewer(value);
 248         }
 249         if (!prefixcmp(var, "man."))
 250                 return add_man_viewer_info(var, value);
 251
 252         return git_default_config(var, value);
 253 }
 254
 255 /* most GUI terminals set COLUMNS (although some don't export it) */
 256 static int term_columns(void)
 257 {
 258         char *col_string = getenv("COLUMNS");
 259         int n_cols;
 260
 261         if (col_string && (n_cols = atoi(col_string)) > 0)
 262                 return n_cols;
 263
 264 #ifdef TIOCGWINSZ
 265         {
 266                 struct winsize ws;
 267                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
 268                         if (ws.ws_col)
 269                                 return ws.ws_col;
 270                 }
 271         }
 272 #endif
 273
 274         return 80;
 275 }
 276
 277 static inline void mput_char(char c, unsigned int num)
 278 {
 279         while(num--)
 280                 putchar(c);
 281 }
 282
 283 static struct cmdnames {
 284         int alloc;
 285         int cnt;
 286         struct cmdname {
 287                 size_t len;
 288                 char name[1];
 289         } **names;
 290 } main_cmds, other_cmds;
 291
 292 static void add_cmdname(struct cmdnames *cmds, const char *name, int len)
 293 {
 294         struct cmdname *ent = xmalloc(sizeof(*ent) + len);
 295
 296         ent->len = len;
 297         memcpy(ent->name, name, len);
 298         ent->name[len] = 0;
 299
 300         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
 301         cmds->names[cmds->cnt++] = ent;
 302 }
 303
 304 static int cmdname_compare(const void *a_, const void *b_)
 305 {
 306         struct cmdname *a = *(struct cmdname **)a_;
 307         struct cmdname *b = *(struct cmdname **)b_;
 308         return strcmp(a->name, b->name);
 309 }
 310
 311 static void uniq(struct cmdnames *cmds)
 312 {
 313         int i, j;
 314
 315         if (!cmds->cnt)
 316                 return;
 317
 318         for (i = j = 1; i < cmds->cnt; i++)
 319                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
 320                         cmds->names[j++] = cmds->names[i];
 321
 322         cmds->cnt = j;
 323 }
 324
 325 static void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
 326 {
 327         int ci, cj, ei;
 328         int cmp;
 329
 330         ci = cj = ei = 0;
 331         while (ci < cmds->cnt && ei < excludes->cnt) {
 332                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
 333                 if (cmp < 0)
 334                         cmds->names[cj++] = cmds->names[ci++];
 335                 else if (cmp == 0)
 336                         ci++, ei++;
 337                 else if (cmp > 0)
 338                         ei++;
 339         }
 340
 341         while (ci < cmds->cnt)
 342                 cmds->names[cj++] = cmds->names[ci++];
 343
 344         cmds->cnt = cj;
 345 }
 346
 347 static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 348 {
 349         int cols = 1, rows;
 350         int space = longest + 1; /* min 1 SP between words */
 351         int max_cols = term_columns() - 1; /* don't print *on* the edge */
 352         int i, j;
 353
 354         if (space < max_cols)
 355                 cols = max_cols / space;
 356         rows = (cmds->cnt + cols - 1) / cols;
 357
 358         for (i = 0; i < rows; i++) {
 359                 printf("  ");
 360
 361                 for (j = 0; j < cols; j++) {
 362                         int n = j * rows + i;
 363                         int size = space;
 364                         if (n >= cmds->cnt)
 365                                 break;
 366                         if (j == cols-1 || n + rows >= cmds->cnt)
 367                                 size = 1;
 368                         printf("%-*s", size, cmds->names[n]->name);
 369                 }
 370                 putchar('\n');
 371         }
 372 }
 373
 374 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 375                                          const char *path)
 376 {
 377         unsigned int longest = 0;
 378         const char *prefix = "git-";
 379         int prefix_len = strlen(prefix);
 380         DIR *dir = opendir(path);
 381         struct dirent *de;
 382
 383         if (!dir || chdir(path))
 384                 return 0;
 385
 386         while ((de = readdir(dir)) != NULL) {
 387                 struct stat st;
 388                 int entlen;
 389
 390                 if (prefixcmp(de->d_name, prefix))
 391                         continue;
 392
 393                 if (stat(de->d_name, &st) || /* stat, not lstat */
 394                     !S_ISREG(st.st_mode) ||
 395                     !(st.st_mode & S_IXUSR))
 396                         continue;
 397
 398                 entlen = strlen(de->d_name) - prefix_len;
 399                 if (has_extension(de->d_name, ".exe"))
 400                         entlen -= 4;
 401
 402                 if (longest < entlen)
 403                         longest = entlen;
 404
 405                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 406         }
 407         closedir(dir);
 408
 409         return longest;
 410 }
 411
 412 static unsigned int load_command_list(void)
 413 {
 414         unsigned int longest = 0;
 415         unsigned int len;
 416         const char *env_path = getenv("PATH");
 417         char *paths, *path, *colon;
 418         const char *exec_path = git_exec_path();
 419
 420         if (exec_path)
 421                 longest = list_commands_in_dir(&main_cmds, exec_path);
 422
 423         if (!env_path) {
 424                 fprintf(stderr, "PATH not set\n");
 425                 exit(1);
 426         }
 427
 428         path = paths = xstrdup(env_path);
 429         while (1) {
 430                 if ((colon = strchr(path, ':')))
 431                         *colon = 0;
 432
 433                 len = list_commands_in_dir(&other_cmds, path);
 434                 if (len > longest)
 435                         longest = len;
 436
 437                 if (!colon)
 438                         break;
 439                 path = colon + 1;
 440         }
 441         free(paths);
 442
 443         qsort(main_cmds.names, main_cmds.cnt,
 444               sizeof(*main_cmds.names), cmdname_compare);
 445         uniq(&main_cmds);
 446
 447         qsort(other_cmds.names, other_cmds.cnt,
 448               sizeof(*other_cmds.names), cmdname_compare);
 449         uniq(&other_cmds);
 450         exclude_cmds(&other_cmds, &main_cmds);
 451
 452         return longest;
 453 }
 454
 455 static void list_commands(void)
 456 {
 457         unsigned int longest = load_command_list();
 458         const char *exec_path = git_exec_path();
 459
 460         if (main_cmds.cnt) {
 461                 printf("available git commands in '%s'\n", exec_path);
 462                 printf("----------------------------");
 463                 mput_char('-', strlen(exec_path));
 464                 putchar('\n');
 465                 pretty_print_string_list(&main_cmds, longest);
 466                 putchar('\n');
 467         }
 468
 469         if (other_cmds.cnt) {
 470                 printf("git commands available from elsewhere on your $PATH\n");
 471                 printf("---------------------------------------------------\n");
 472                 pretty_print_string_list(&other_cmds, longest);
 473                 putchar('\n');
 474         }
 475 }
 476
 477 void list_common_cmds_help(void)
 478 {
 479         int i, longest = 0;
 480
 481         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 482                 if (longest < strlen(common_cmds[i].name))
 483                         longest = strlen(common_cmds[i].name);
 484         }
 485
 486         puts("The most commonly used git commands are:");
 487         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 488                 printf("   %s   ", common_cmds[i].name);
 489                 mput_char(' ', longest - strlen(common_cmds[i].name));
 490                 puts(common_cmds[i].help);
 491         }
 492 }
 493
 494 static int is_in_cmdlist(struct cmdnames *c, const char *s)
 495 {
 496         int i;
 497         for (i = 0; i < c->cnt; i++)
 498                 if (!strcmp(s, c->names[i]->name))
 499                         return 1;
 500         return 0;
 501 }
 502
 503 static int is_git_command(const char *s)
 504 {
 505         load_command_list();
 506         return is_in_cmdlist(&main_cmds, s) ||
 507                 is_in_cmdlist(&other_cmds, s);
 508 }
 509
 510 static const char *cmd_to_page(const char *git_cmd)
 511 {
 512         if (!git_cmd)
 513                 return "git";
 514         else if (!prefixcmp(git_cmd, "git"))
 515                 return git_cmd;
 516         else {
 517                 int page_len = strlen(git_cmd) + 4;
 518                 char *p = xmalloc(page_len + 1);
 519                 strcpy(p, "git-");
 520                 strcpy(p + 4, git_cmd);
 521                 p[page_len] = 0;
 522                 return p;
 523         }
 524 }
 525
 526 static void setup_man_path(void)
 527 {
 528         struct strbuf new_path;
 529         const char *old_path = getenv("MANPATH");
 530
 531         strbuf_init(&new_path, 0);
 532
 533         /* We should always put ':' after our path. If there is no
 534          * old_path, the ':' at the end will let 'man' to try
 535          * system-wide paths after ours to find the manual page. If
 536          * there is old_path, we need ':' as delimiter. */
 537         strbuf_addstr(&new_path, GIT_MAN_PATH);
 538         strbuf_addch(&new_path, ':');
 539         if (old_path)
 540                 strbuf_addstr(&new_path, old_path);
 541
 542         setenv("MANPATH", new_path.buf, 1);
 543
 544         strbuf_release(&new_path);
 545 }
 546
 547 static void exec_viewer(const char *name, const char *page)
 548 {
 549         const char *path = get_man_viewer_info(name);
 550
 551         if (!strcasecmp(name, "man"))
 552                 exec_man_man(path, page);
 553         else if (!strcasecmp(name, "woman"))
 554                 exec_woman_emacs(path, page);
 555         else if (!strcasecmp(name, "konqueror"))
 556                 exec_man_konqueror(path, page);
 557         else
 558                 warning("'%s': unsupported man viewer.", name);
 559 }
 560
 561 static void show_man_page(const char *git_cmd)
 562 {
 563         struct man_viewer_list *viewer;
 564         const char *page = cmd_to_page(git_cmd);
 565
 566         setup_man_path();
 567         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 568         {
 569                 exec_viewer(viewer->name, page); /* will return when unable */
 570         }
 571         exec_viewer("man", page);
 572         die("no man viewer handled the request");
 573 }
 574
 575 static void show_info_page(const char *git_cmd)
 576 {
 577         const char *page = cmd_to_page(git_cmd);
 578         setenv("INFOPATH", GIT_INFO_PATH, 1);
 579         execlp("info", "info", "gitman", page, NULL);
 580 }
 581
 582 static void get_html_page_path(struct strbuf *page_path, const char *page)
 583 {
 584         struct stat st;
 585
 586         /* Check that we have a git documentation directory. */
 587         if (stat(GIT_HTML_PATH "/git.html", &st) || !S_ISREG(st.st_mode))
 588                 die("'%s': not a documentation directory.", GIT_HTML_PATH);
 589
 590         strbuf_init(page_path, 0);
 591         strbuf_addf(page_path, GIT_HTML_PATH "/%s.html", page);
 592 }
 593
 594 static void show_html_page(const char *git_cmd)
 595 {
 596         const char *page = cmd_to_page(git_cmd);
 597         struct strbuf page_path; /* it leaks but we exec bellow */
 598
 599         get_html_page_path(&page_path, page);
 600
 601         execl_git_cmd("web--browse", "-c", "help.browser", page_path.buf, NULL);
 602 }
 603
 604 void help_unknown_cmd(const char *cmd)
 605 {
 606         fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
 607         exit(1);
 608 }
 609
 610 int cmd_version(int argc, const char **argv, const char *prefix)
 611 {
 612         printf("git version %s\n", git_version_string);
 613         return 0;
 614 }
 615
 616 int cmd_help(int argc, const char **argv, const char *prefix)
 617 {
 618         int nongit;
 619         const char *alias;
 620
 621         setup_git_directory_gently(&nongit);
 622         git_config(git_help_config);
 623
 624         argc = parse_options(argc, argv, builtin_help_options,
 625                         builtin_help_usage, 0);
 626
 627         if (show_all) {
 628                 printf("usage: %s\n\n", git_usage_string);
 629                 list_commands();
 630                 return 0;
 631         }
 632
 633         if (!argv[0]) {
 634                 printf("usage: %s\n\n", git_usage_string);
 635                 list_common_cmds_help();
 636                 return 0;
 637         }
 638
 639         alias = alias_lookup(argv[0]);
 640         if (alias && !is_git_command(argv[0])) {
 641                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
 642                 return 0;
 643         }
 644
 645         switch (help_format) {
 646         case HELP_FORMAT_MAN:
 647                 show_man_page(argv[0]);
 648                 break;
 649         case HELP_FORMAT_INFO:
 650                 show_info_page(argv[0]);
 651                 break;
 652         case HELP_FORMAT_WEB:
 653                 show_html_page(argv[0]);
 654                 break;
 655         }
 656
 657         return 0;
 658 }