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