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
  12 enum help_format {
  13         HELP_FORMAT_MAN,
  14         HELP_FORMAT_INFO,
  15         HELP_FORMAT_WEB,
  16 };
  17
  18 static int show_all = 0;
  19 static enum help_format help_format = HELP_FORMAT_MAN;
  20 static struct option builtin_help_options[] = {
  21         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
  22         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  23         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  24                         HELP_FORMAT_WEB),
  25         OPT_SET_INT('i', "info", &help_format, "show info page",
  26                         HELP_FORMAT_INFO),
  27 };
  28
  29 static const char * const builtin_help_usage[] = {
  30         "git-help [--all] [--man|--web|--info] [command]",
  31         NULL
  32 };
  33
  34 static enum help_format parse_help_format(const char *format)
  35 {
  36         if (!strcmp(format, "man"))
  37                 return HELP_FORMAT_MAN;
  38         if (!strcmp(format, "info"))
  39                 return HELP_FORMAT_INFO;
  40         if (!strcmp(format, "web") || !strcmp(format, "html"))
  41                 return HELP_FORMAT_WEB;
  42         die("unrecognized help format '%s'", format);
  43 }
  44
  45 static int git_help_config(const char *var, const char *value)
  46 {
  47         if (!strcmp(var, "help.format")) {
  48                 if (!value)
  49                         return config_error_nonbool(var);
  50                 help_format = parse_help_format(value);
  51                 return 0;
  52         }
  53         return git_default_config(var, value);
  54 }
  55
  56 /* most GUI terminals set COLUMNS (although some don't export it) */
  57 static int term_columns(void)
  58 {
  59         char *col_string = getenv("COLUMNS");
  60         int n_cols;
  61
  62         if (col_string && (n_cols = atoi(col_string)) > 0)
  63                 return n_cols;
  64
  65 #ifdef TIOCGWINSZ
  66         {
  67                 struct winsize ws;
  68                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
  69                         if (ws.ws_col)
  70                                 return ws.ws_col;
  71                 }
  72         }
  73 #endif
  74
  75         return 80;
  76 }
  77
  78 static inline void mput_char(char c, unsigned int num)
  79 {
  80         while(num--)
  81                 putchar(c);
  82 }
  83
  84 static struct cmdnames {
  85         int alloc;
  86         int cnt;
  87         struct cmdname {
  88                 size_t len;
  89                 char name[1];
  90         } **names;
  91 } main_cmds, other_cmds;
  92
  93 static void add_cmdname(struct cmdnames *cmds, const char *name, int len)
  94 {
  95         struct cmdname *ent = xmalloc(sizeof(*ent) + len);
  96
  97         ent->len = len;
  98         memcpy(ent->name, name, len);
  99         ent->name[len] = 0;
 100
 101         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
 102         cmds->names[cmds->cnt++] = ent;
 103 }
 104
 105 static int cmdname_compare(const void *a_, const void *b_)
 106 {
 107         struct cmdname *a = *(struct cmdname **)a_;
 108         struct cmdname *b = *(struct cmdname **)b_;
 109         return strcmp(a->name, b->name);
 110 }
 111
 112 static void uniq(struct cmdnames *cmds)
 113 {
 114         int i, j;
 115
 116         if (!cmds->cnt)
 117                 return;
 118
 119         for (i = j = 1; i < cmds->cnt; i++)
 120                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
 121                         cmds->names[j++] = cmds->names[i];
 122
 123         cmds->cnt = j;
 124 }
 125
 126 static void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
 127 {
 128         int ci, cj, ei;
 129         int cmp;
 130
 131         ci = cj = ei = 0;
 132         while (ci < cmds->cnt && ei < excludes->cnt) {
 133                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
 134                 if (cmp < 0)
 135                         cmds->names[cj++] = cmds->names[ci++];
 136                 else if (cmp == 0)
 137                         ci++, ei++;
 138                 else if (cmp > 0)
 139                         ei++;
 140         }
 141
 142         while (ci < cmds->cnt)
 143                 cmds->names[cj++] = cmds->names[ci++];
 144
 145         cmds->cnt = cj;
 146 }
 147
 148 static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 149 {
 150         int cols = 1, rows;
 151         int space = longest + 1; /* min 1 SP between words */
 152         int max_cols = term_columns() - 1; /* don't print *on* the edge */
 153         int i, j;
 154
 155         if (space < max_cols)
 156                 cols = max_cols / space;
 157         rows = (cmds->cnt + cols - 1) / cols;
 158
 159         for (i = 0; i < rows; i++) {
 160                 printf("  ");
 161
 162                 for (j = 0; j < cols; j++) {
 163                         int n = j * rows + i;
 164                         int size = space;
 165                         if (n >= cmds->cnt)
 166                                 break;
 167                         if (j == cols-1 || n + rows >= cmds->cnt)
 168                                 size = 1;
 169                         printf("%-*s", size, cmds->names[n]->name);
 170                 }
 171                 putchar('\n');
 172         }
 173 }
 174
 175 static int is_executable(const char *name)
 176 {
 177         struct stat st;
 178
 179         if (stat(name, &st) || /* stat, not lstat */
 180             !S_ISREG(st.st_mode))
 181                 return 0;
 182
 183 #ifdef __MINGW32__
 184         /* cannot trust the executable bit, peek into the file instead */
 185         char buf[3] = { 0 };
 186         int n;
 187         int fd = open(name, O_RDONLY);
 188         st.st_mode &= ~S_IXUSR;
 189         if (fd >= 0) {
 190                 n = read(fd, buf, 2);
 191                 if (n == 2)
 192                         /* DOS executables start with "MZ" */
 193                         if (!strcmp(buf, "#!") || !strcmp(buf, "MZ"))
 194                                 st.st_mode |= S_IXUSR;
 195                 close(fd);
 196         }
 197 #endif
 198         return st.st_mode & S_IXUSR;
 199 }
 200
 201 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 202                                          const char *path)
 203 {
 204         unsigned int longest = 0;
 205         const char *prefix = "git-";
 206         int prefix_len = strlen(prefix);
 207         DIR *dir = opendir(path);
 208         struct dirent *de;
 209
 210         if (!dir || chdir(path))
 211                 return 0;
 212
 213         while ((de = readdir(dir)) != NULL) {
 214                 int entlen;
 215
 216                 if (prefixcmp(de->d_name, prefix))
 217                         continue;
 218
 219                 if (!is_executable(de->d_name))
 220                         continue;
 221
 222                 entlen = strlen(de->d_name) - prefix_len;
 223                 if (has_extension(de->d_name, ".exe"))
 224                         entlen -= 4;
 225
 226                 if (longest < entlen)
 227                         longest = entlen;
 228
 229                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 230         }
 231         closedir(dir);
 232
 233         return longest;
 234 }
 235
 236 static unsigned int load_command_list(void)
 237 {
 238         unsigned int longest = 0;
 239         unsigned int len;
 240         const char *env_path = getenv("PATH");
 241         char *paths, *path, *colon;
 242         const char *exec_path = git_exec_path();
 243 #ifdef __MINGW32__
 244         char sep = ';';
 245 #else
 246         char sep = ':';
 247 #endif
 248
 249         if (exec_path)
 250                 longest = list_commands_in_dir(&main_cmds, exec_path);
 251
 252         if (!env_path) {
 253                 fprintf(stderr, "PATH not set\n");
 254                 exit(1);
 255         }
 256
 257         path = paths = xstrdup(env_path);
 258         while (1) {
 259                 if ((colon = strchr(path, sep)))
 260                         *colon = 0;
 261
 262                 len = list_commands_in_dir(&other_cmds, path);
 263                 if (len > longest)
 264                         longest = len;
 265
 266                 if (!colon)
 267                         break;
 268                 path = colon + 1;
 269         }
 270         free(paths);
 271
 272         qsort(main_cmds.names, main_cmds.cnt,
 273               sizeof(*main_cmds.names), cmdname_compare);
 274         uniq(&main_cmds);
 275
 276         qsort(other_cmds.names, other_cmds.cnt,
 277               sizeof(*other_cmds.names), cmdname_compare);
 278         uniq(&other_cmds);
 279         exclude_cmds(&other_cmds, &main_cmds);
 280
 281         return longest;
 282 }
 283
 284 static void list_commands(void)
 285 {
 286         unsigned int longest = load_command_list();
 287         const char *exec_path = git_exec_path();
 288
 289         if (main_cmds.cnt) {
 290                 printf("available git commands in '%s'\n", exec_path);
 291                 printf("----------------------------");
 292                 mput_char('-', strlen(exec_path));
 293                 putchar('\n');
 294                 pretty_print_string_list(&main_cmds, longest);
 295                 putchar('\n');
 296         }
 297
 298         if (other_cmds.cnt) {
 299                 printf("git commands available from elsewhere on your $PATH\n");
 300                 printf("---------------------------------------------------\n");
 301                 pretty_print_string_list(&other_cmds, longest);
 302                 putchar('\n');
 303         }
 304 }
 305
 306 void list_common_cmds_help(void)
 307 {
 308         int i, longest = 0;
 309
 310         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 311                 if (longest < strlen(common_cmds[i].name))
 312                         longest = strlen(common_cmds[i].name);
 313         }
 314
 315         puts("The most commonly used git commands are:");
 316         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 317                 printf("   %s   ", common_cmds[i].name);
 318                 mput_char(' ', longest - strlen(common_cmds[i].name));
 319                 puts(common_cmds[i].help);
 320         }
 321 }
 322
 323 static int is_in_cmdlist(struct cmdnames *c, const char *s)
 324 {
 325         int i;
 326         for (i = 0; i < c->cnt; i++)
 327                 if (!strcmp(s, c->names[i]->name))
 328                         return 1;
 329         return 0;
 330 }
 331
 332 static int is_git_command(const char *s)
 333 {
 334         load_command_list();
 335         return is_in_cmdlist(&main_cmds, s) ||
 336                 is_in_cmdlist(&other_cmds, s);
 337 }
 338
 339 static const char *cmd_to_page(const char *git_cmd)
 340 {
 341         if (!git_cmd)
 342                 return "git";
 343         else if (!prefixcmp(git_cmd, "git"))
 344                 return git_cmd;
 345         else {
 346                 int page_len = strlen(git_cmd) + 4;
 347                 char *p = xmalloc(page_len + 1);
 348                 strcpy(p, "git-");
 349                 strcpy(p + 4, git_cmd);
 350                 p[page_len] = 0;
 351                 return p;
 352         }
 353 }
 354
 355 static void setup_man_path(void)
 356 {
 357         struct strbuf new_path;
 358         const char *old_path = getenv("MANPATH");
 359
 360         strbuf_init(&new_path, 0);
 361
 362         /* We should always put ':' after our path. If there is no
 363          * old_path, the ':' at the end will let 'man' to try
 364          * system-wide paths after ours to find the manual page. If
 365          * there is old_path, we need ':' as delimiter. */
 366         strbuf_addstr(&new_path, GIT_MAN_PATH);
 367         strbuf_addch(&new_path, ':');
 368         if (old_path)
 369                 strbuf_addstr(&new_path, old_path);
 370
 371         setenv("MANPATH", new_path.buf, 1);
 372
 373         strbuf_release(&new_path);
 374 }
 375
 376 static void show_man_page(const char *git_cmd)
 377 {
 378         const char *page = cmd_to_page(git_cmd);
 379         setup_man_path();
 380         execlp("man", "man", page, NULL);
 381 }
 382
 383 static void show_info_page(const char *git_cmd)
 384 {
 385         const char *page = cmd_to_page(git_cmd);
 386         setenv("INFOPATH", GIT_INFO_PATH, 1);
 387         execlp("info", "info", "gitman", page, NULL);
 388 }
 389
 390 static void get_html_page_path(struct strbuf *page_path, const char *page)
 391 {
 392         struct stat st;
 393
 394         /* Check that we have a git documentation directory. */
 395         if (stat(GIT_HTML_PATH "/git.html", &st) || !S_ISREG(st.st_mode))
 396                 die("'%s': not a documentation directory.", GIT_HTML_PATH);
 397
 398         strbuf_init(page_path, 0);
 399         strbuf_addf(page_path, GIT_HTML_PATH "/%s.html", page);
 400 }
 401
 402 static void show_html_page(const char *git_cmd)
 403 {
 404         const char *page = cmd_to_page(git_cmd);
 405         struct strbuf page_path; /* it leaks but we exec bellow */
 406
 407         get_html_page_path(&page_path, page);
 408
 409         execl_git_cmd("web--browse", "-c", "help.browser", page_path.buf, NULL);
 410 }
 411
 412 void help_unknown_cmd(const char *cmd)
 413 {
 414         fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
 415         exit(1);
 416 }
 417
 418 int cmd_version(int argc, const char **argv, const char *prefix)
 419 {
 420         printf("git version %s\n", git_version_string);
 421         return 0;
 422 }
 423
 424 int cmd_help(int argc, const char **argv, const char *prefix)
 425 {
 426         int nongit;
 427         const char *alias;
 428
 429         setup_git_directory_gently(&nongit);
 430         git_config(git_help_config);
 431
 432         argc = parse_options(argc, argv, builtin_help_options,
 433                         builtin_help_usage, 0);
 434
 435         if (show_all) {
 436                 printf("usage: %s\n\n", git_usage_string);
 437                 list_commands();
 438                 return 0;
 439         }
 440
 441         if (!argv[0]) {
 442                 printf("usage: %s\n\n", git_usage_string);
 443                 list_common_cmds_help();
 444                 return 0;
 445         }
 446
 447         alias = alias_lookup(argv[0]);
 448         if (alias && !is_git_command(argv[0])) {
 449                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
 450                 return 0;
 451         }
 452
 453         switch (help_format) {
 454         case HELP_FORMAT_MAN:
 455                 show_man_page(argv[0]);
 456                 break;
 457         case HELP_FORMAT_INFO:
 458                 show_info_page(argv[0]);
 459                 break;
 460         case HELP_FORMAT_WEB:
 461                 show_html_page(argv[0]);
 462                 break;
 463         }
 464
 465         return 0;
 466 }