help.c

   1 #include "cache.h"
   2 #include "builtin.h"
   3 #include "exec_cmd.h"
   4 #include "levenshtein.h"
   5 #include "help.h"
   6 #include "common-cmds.h"
   7
   8 /* most GUI terminals set COLUMNS (although some don't export it) */
   9 static int term_columns(void)
  10 {
  11         char *col_string = getenv("COLUMNS");
  12         int n_cols;
  13
  14         if (col_string && (n_cols = atoi(col_string)) > 0)
  15                 return n_cols;
  16
  17 #ifdef TIOCGWINSZ
  18         {
  19                 struct winsize ws;
  20                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
  21                         if (ws.ws_col)
  22                                 return ws.ws_col;
  23                 }
  24         }
  25 #endif
  26
  27         return 80;
  28 }
  29
  30 void add_cmdname(struct cmdnames *cmds, const char *name, int len)
  31 {
  32         struct cmdname *ent = xmalloc(sizeof(*ent) + len + 1);
  33
  34         ent->len = len;
  35         memcpy(ent->name, name, len);
  36         ent->name[len] = 0;
  37
  38         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
  39         cmds->names[cmds->cnt++] = ent;
  40 }
  41
  42 static void clean_cmdnames(struct cmdnames *cmds)
  43 {
  44         int i;
  45         for (i = 0; i < cmds->cnt; ++i)
  46                 free(cmds->names[i]);
  47         free(cmds->names);
  48         cmds->cnt = 0;
  49         cmds->alloc = 0;
  50 }
  51
  52 static int cmdname_compare(const void *a_, const void *b_)
  53 {
  54         struct cmdname *a = *(struct cmdname **)a_;
  55         struct cmdname *b = *(struct cmdname **)b_;
  56         return strcmp(a->name, b->name);
  57 }
  58
  59 static void uniq(struct cmdnames *cmds)
  60 {
  61         int i, j;
  62
  63         if (!cmds->cnt)
  64                 return;
  65
  66         for (i = j = 1; i < cmds->cnt; i++)
  67                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
  68                         cmds->names[j++] = cmds->names[i];
  69
  70         cmds->cnt = j;
  71 }
  72
  73 void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
  74 {
  75         int ci, cj, ei;
  76         int cmp;
  77
  78         ci = cj = ei = 0;
  79         while (ci < cmds->cnt && ei < excludes->cnt) {
  80                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
  81                 if (cmp < 0)
  82                         cmds->names[cj++] = cmds->names[ci++];
  83                 else if (cmp == 0)
  84                         ci++, ei++;
  85                 else if (cmp > 0)
  86                         ei++;
  87         }
  88
  89         while (ci < cmds->cnt)
  90                 cmds->names[cj++] = cmds->names[ci++];
  91
  92         cmds->cnt = cj;
  93 }
  94
  95 static void pretty_print_string_list(struct cmdnames *cmds, int longest)
  96 {
  97         int cols = 1, rows;
  98         int space = longest + 1; /* min 1 SP between words */
  99         int max_cols = term_columns() - 1; /* don't print *on* the edge */
 100         int i, j;
 101
 102         if (space < max_cols)
 103                 cols = max_cols / space;
 104         rows = DIV_ROUND_UP(cmds->cnt, cols);
 105
 106         for (i = 0; i < rows; i++) {
 107                 printf("  ");
 108
 109                 for (j = 0; j < cols; j++) {
 110                         int n = j * rows + i;
 111                         int size = space;
 112                         if (n >= cmds->cnt)
 113                                 break;
 114                         if (j == cols-1 || n + rows >= cmds->cnt)
 115                                 size = 1;
 116                         printf("%-*s", size, cmds->names[n]->name);
 117                 }
 118                 putchar('\n');
 119         }
 120 }
 121
 122 static int is_executable(const char *name)
 123 {
 124         struct stat st;
 125
 126         if (stat(name, &st) || /* stat, not lstat */
 127             !S_ISREG(st.st_mode))
 128                 return 0;
 129
 130 #if defined(WIN32) || defined(__CYGWIN__)
 131 #if defined(__CYGWIN__)
 132 if ((st.st_mode & S_IXUSR) == 0)
 133 #endif
 134 {       /* cannot trust the executable bit, peek into the file instead */
 135         char buf[3] = { 0 };
 136         int n;
 137         int fd = open(name, O_RDONLY);
 138         st.st_mode &= ~S_IXUSR;
 139         if (fd >= 0) {
 140                 n = read(fd, buf, 2);
 141                 if (n == 2)
 142                         /* DOS executables start with "MZ" */
 143                         if (!strcmp(buf, "#!") || !strcmp(buf, "MZ"))
 144                                 st.st_mode |= S_IXUSR;
 145                 close(fd);
 146         }
 147 }
 148 #endif
 149         return st.st_mode & S_IXUSR;
 150 }
 151
 152 static void list_commands_in_dir(struct cmdnames *cmds,
 153                                          const char *path,
 154                                          const char *prefix)
 155 {
 156         int prefix_len;
 157         DIR *dir = opendir(path);
 158         struct dirent *de;
 159         struct strbuf buf = STRBUF_INIT;
 160         int len;
 161
 162         if (!dir)
 163                 return;
 164         if (!prefix)
 165                 prefix = "git-";
 166         prefix_len = strlen(prefix);
 167
 168         strbuf_addf(&buf, "%s/", path);
 169         len = buf.len;
 170
 171         while ((de = readdir(dir)) != NULL) {
 172                 int entlen;
 173
 174                 if (prefixcmp(de->d_name, prefix))
 175                         continue;
 176
 177                 strbuf_setlen(&buf, len);
 178                 strbuf_addstr(&buf, de->d_name);
 179                 if (!is_executable(buf.buf))
 180                         continue;
 181
 182                 entlen = strlen(de->d_name) - prefix_len;
 183                 if (has_extension(de->d_name, ".exe"))
 184                         entlen -= 4;
 185
 186                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 187         }
 188         closedir(dir);
 189         strbuf_release(&buf);
 190 }
 191
 192 void load_command_list(const char *prefix,
 193                 struct cmdnames *main_cmds,
 194                 struct cmdnames *other_cmds)
 195 {
 196         const char *env_path = getenv("PATH");
 197         const char *exec_path = git_exec_path();
 198
 199         if (exec_path) {
 200                 list_commands_in_dir(main_cmds, exec_path, prefix);
 201                 qsort(main_cmds->names, main_cmds->cnt,
 202                       sizeof(*main_cmds->names), cmdname_compare);
 203                 uniq(main_cmds);
 204         }
 205
 206         if (env_path) {
 207                 char *paths, *path, *colon;
 208                 path = paths = xstrdup(env_path);
 209                 while (1) {
 210                         if ((colon = strchr(path, PATH_SEP)))
 211                                 *colon = 0;
 212                         if (!exec_path || strcmp(path, exec_path))
 213                                 list_commands_in_dir(other_cmds, path, prefix);
 214
 215                         if (!colon)
 216                                 break;
 217                         path = colon + 1;
 218                 }
 219                 free(paths);
 220
 221                 qsort(other_cmds->names, other_cmds->cnt,
 222                       sizeof(*other_cmds->names), cmdname_compare);
 223                 uniq(other_cmds);
 224         }
 225         exclude_cmds(other_cmds, main_cmds);
 226 }
 227
 228 void list_commands(const char *title, struct cmdnames *main_cmds,
 229                    struct cmdnames *other_cmds)
 230 {
 231         int i, longest = 0;
 232
 233         for (i = 0; i < main_cmds->cnt; i++)
 234                 if (longest < main_cmds->names[i]->len)
 235                         longest = main_cmds->names[i]->len;
 236         for (i = 0; i < other_cmds->cnt; i++)
 237                 if (longest < other_cmds->names[i]->len)
 238                         longest = other_cmds->names[i]->len;
 239
 240         if (main_cmds->cnt) {
 241                 const char *exec_path = git_exec_path();
 242                 printf("available %s in '%s'\n", title, exec_path);
 243                 printf("----------------");
 244                 mput_char('-', strlen(title) + strlen(exec_path));
 245                 putchar('\n');
 246                 pretty_print_string_list(main_cmds, longest);
 247                 putchar('\n');
 248         }
 249
 250         if (other_cmds->cnt) {
 251                 printf("%s available from elsewhere on your $PATH\n", title);
 252                 printf("---------------------------------------");
 253                 mput_char('-', strlen(title));
 254                 putchar('\n');
 255                 pretty_print_string_list(other_cmds, longest);
 256                 putchar('\n');
 257         }
 258 }
 259
 260 int is_in_cmdlist(struct cmdnames *c, const char *s)
 261 {
 262         int i;
 263         for (i = 0; i < c->cnt; i++)
 264                 if (!strcmp(s, c->names[i]->name))
 265                         return 1;
 266         return 0;
 267 }
 268
 269 static int autocorrect;
 270 static struct cmdnames aliases;
 271
 272 static int git_unknown_cmd_config(const char *var, const char *value, void *cb)
 273 {
 274         if (!strcmp(var, "help.autocorrect"))
 275                 autocorrect = git_config_int(var,value);
 276         /* Also use aliases for command lookup */
 277         if (!prefixcmp(var, "alias."))
 278                 add_cmdname(&aliases, var + 6, strlen(var + 6));
 279
 280         return git_default_config(var, value, cb);
 281 }
 282
 283 static int levenshtein_compare(const void *p1, const void *p2)
 284 {
 285         const struct cmdname *const *c1 = p1, *const *c2 = p2;
 286         const char *s1 = (*c1)->name, *s2 = (*c2)->name;
 287         int l1 = (*c1)->len;
 288         int l2 = (*c2)->len;
 289         return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
 290 }
 291
 292 static void add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
 293 {
 294         int i;
 295         ALLOC_GROW(cmds->names, cmds->cnt + old->cnt, cmds->alloc);
 296
 297         for (i = 0; i < old->cnt; i++)
 298                 cmds->names[cmds->cnt++] = old->names[i];
 299         free(old->names);
 300         old->cnt = 0;
 301         old->names = NULL;
 302 }
 303
 304 /* An empirically derived magic number */
 305 #define SIMILARITY_FLOOR 7
 306 #define SIMILAR_ENOUGH(x) ((x) < SIMILARITY_FLOOR)
 307
 308 const char *help_unknown_cmd(const char *cmd)
 309 {
 310         int i, n, best_similarity = 0;
 311         struct cmdnames main_cmds, other_cmds;
 312
 313         memset(&main_cmds, 0, sizeof(main_cmds));
 314         memset(&other_cmds, 0, sizeof(other_cmds));
 315         memset(&aliases, 0, sizeof(aliases));
 316
 317         git_config(git_unknown_cmd_config, NULL);
 318
 319         load_command_list("git-", &main_cmds, &other_cmds);
 320
 321         add_cmd_list(&main_cmds, &aliases);
 322         add_cmd_list(&main_cmds, &other_cmds);
 323         qsort(main_cmds.names, main_cmds.cnt,
 324               sizeof(main_cmds.names), cmdname_compare);
 325         uniq(&main_cmds);
 326
 327         /* This abuses cmdname->len for levenshtein distance */
 328         for (i = 0, n = 0; i < main_cmds.cnt; i++) {
 329                 int cmp = 0; /* avoid compiler stupidity */
 330                 const char *candidate = main_cmds.names[i]->name;
 331
 332                 /* Does the candidate appear in common_cmds list? */
 333                 while (n < ARRAY_SIZE(common_cmds) &&
 334                        (cmp = strcmp(common_cmds[n].name, candidate)) < 0)
 335                         n++;
 336                 if ((n < ARRAY_SIZE(common_cmds)) && !cmp) {
 337                         /* Yes, this is one of the common commands */
 338                         n++; /* use the entry from common_cmds[] */
 339                         if (!prefixcmp(candidate, cmd)) {
 340                                 /* Give prefix match a very good score */
 341                                 main_cmds.names[i]->len = 0;
 342                                 continue;
 343                         }
 344                 }
 345
 346                 main_cmds.names[i]->len =
 347                         levenshtein(cmd, candidate, 0, 2, 1, 4) + 1;
 348         }
 349
 350         qsort(main_cmds.names, main_cmds.cnt,
 351               sizeof(*main_cmds.names), levenshtein_compare);
 352
 353         if (!main_cmds.cnt)
 354                 die ("Uh oh. Your system reports no Git commands at all.");
 355
 356         /* skip and count prefix matches */
 357         for (n = 0; n < main_cmds.cnt && !main_cmds.names[n]->len; n++)
 358                 ; /* still counting */
 359
 360         if (main_cmds.cnt <= n) {
 361                 /* prefix matches with everything? that is too ambiguous */
 362                 best_similarity = SIMILARITY_FLOOR + 1;
 363         } else {
 364                 /* count all the most similar ones */
 365                 for (best_similarity = main_cmds.names[n++]->len;
 366                      (n < main_cmds.cnt &&
 367                       best_similarity == main_cmds.names[n]->len);
 368                      n++)
 369                         ; /* still counting */
 370         }
 371         if (autocorrect && n == 1 && SIMILAR_ENOUGH(best_similarity)) {
 372                 const char *assumed = main_cmds.names[0]->name;
 373                 main_cmds.names[0] = NULL;
 374                 clean_cmdnames(&main_cmds);
 375                 fprintf(stderr, "WARNING: You called a Git command named '%s', "
 376                         "which does not exist.\n"
 377                         "Continuing under the assumption that you meant '%s'\n",
 378                         cmd, assumed);
 379                 if (autocorrect > 0) {
 380                         fprintf(stderr, "in %0.1f seconds automatically...\n",
 381                                 (float)autocorrect/10.0);
 382                         poll(NULL, 0, autocorrect * 100);
 383                 }
 384                 return assumed;
 385         }
 386
 387         fprintf(stderr, "git: '%s' is not a git command. See 'git --help'.\n", cmd);
 388
 389         if (SIMILAR_ENOUGH(best_similarity)) {
 390                 fprintf(stderr, "\nDid you mean %s?\n",
 391                         n < 2 ? "this": "one of these");
 392
 393                 for (i = 0; i < n; i++)
 394                         fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
 395         }
 396
 397         exit(1);
 398 }
 399
 400 int cmd_version(int argc, const char **argv, const char *prefix)
 401 {
 402         printf("git version %s\n", git_version_string);
 403         return 0;
 404 }