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