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                         ci++, ei++;
  69                 else if (cmp > 0)
  70                         ei++;
  71         }
  72
  73         while (ci < cmds->cnt)
  74                 cmds->names[cj++] = cmds->names[ci++];
  75
  76         cmds->cnt = cj;
  77 }
  78
  79 static void pretty_print_string_list(struct cmdnames *cmds,
  80                                      unsigned int colopts)
  81 {
  82         struct string_list list = STRING_LIST_INIT_NODUP;
  83         struct column_options copts;
  84         int i;
  85
  86         for (i = 0; i < cmds->cnt; i++)
  87                 string_list_append(&list, cmds->names[i]->name);
  88         /*
  89          * always enable column display, we only consult column.*
  90          * about layout strategy and stuff
  91          */
  92         colopts = (colopts & ~COL_ENABLE_MASK) | COL_ENABLED;
  93         memset(&copts, 0, sizeof(copts));
  94         copts.indent = "  ";
  95         copts.padding = 2;
  96         print_columns(&list, colopts, &copts);
  97         string_list_clear(&list, 0);
  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(unsigned int colopts,
 207                    struct cmdnames *main_cmds, struct cmdnames *other_cmds)
 208 {
 209         if (main_cmds->cnt) {
 210                 const char *exec_path = git_exec_path();
 211                 printf_ln(_("available git commands in '%s'"), exec_path);
 212                 putchar('\n');
 213                 pretty_print_string_list(main_cmds, colopts);
 214                 putchar('\n');
 215         }
 216
 217         if (other_cmds->cnt) {
 218                 printf_ln(_("git commands available from elsewhere on your $PATH"));
 219                 putchar('\n');
 220                 pretty_print_string_list(other_cmds, colopts);
 221                 putchar('\n');
 222         }
 223 }
 224
 225 int is_in_cmdlist(struct cmdnames *c, const char *s)
 226 {
 227         int i;
 228         for (i = 0; i < c->cnt; i++)
 229                 if (!strcmp(s, c->names[i]->name))
 230                         return 1;
 231         return 0;
 232 }
 233
 234 static int autocorrect;
 235 static struct cmdnames aliases;
 236
 237 static int git_unknown_cmd_config(const char *var, const char *value, void *cb)
 238 {
 239         if (!strcmp(var, "help.autocorrect"))
 240                 autocorrect = git_config_int(var,value);
 241         /* Also use aliases for command lookup */
 242         if (!prefixcmp(var, "alias."))
 243                 add_cmdname(&aliases, var + 6, strlen(var + 6));
 244
 245         return git_default_config(var, value, cb);
 246 }
 247
 248 static int levenshtein_compare(const void *p1, const void *p2)
 249 {
 250         const struct cmdname *const *c1 = p1, *const *c2 = p2;
 251         const char *s1 = (*c1)->name, *s2 = (*c2)->name;
 252         int l1 = (*c1)->len;
 253         int l2 = (*c2)->len;
 254         return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
 255 }
 256
 257 static void add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
 258 {
 259         int i;
 260         ALLOC_GROW(cmds->names, cmds->cnt + old->cnt, cmds->alloc);
 261
 262         for (i = 0; i < old->cnt; i++)
 263                 cmds->names[cmds->cnt++] = old->names[i];
 264         free(old->names);
 265         old->cnt = 0;
 266         old->names = NULL;
 267 }
 268
 269 /* An empirically derived magic number */
 270 #define SIMILARITY_FLOOR 7
 271 #define SIMILAR_ENOUGH(x) ((x) < SIMILARITY_FLOOR)
 272
 273 static const char bad_interpreter_advice[] =
 274         N_("'%s' appears to be a git command, but we were not\n"
 275         "able to execute it. Maybe git-%s is broken?");
 276
 277 const char *help_unknown_cmd(const char *cmd)
 278 {
 279         int i, n, best_similarity = 0;
 280         struct cmdnames main_cmds, other_cmds;
 281
 282         memset(&main_cmds, 0, sizeof(main_cmds));
 283         memset(&other_cmds, 0, sizeof(other_cmds));
 284         memset(&aliases, 0, sizeof(aliases));
 285
 286         git_config(git_unknown_cmd_config, NULL);
 287
 288         load_command_list("git-", &main_cmds, &other_cmds);
 289
 290         add_cmd_list(&main_cmds, &aliases);
 291         add_cmd_list(&main_cmds, &other_cmds);
 292         qsort(main_cmds.names, main_cmds.cnt,
 293               sizeof(main_cmds.names), cmdname_compare);
 294         uniq(&main_cmds);
 295
 296         /* This abuses cmdname->len for levenshtein distance */
 297         for (i = 0, n = 0; i < main_cmds.cnt; i++) {
 298                 int cmp = 0; /* avoid compiler stupidity */
 299                 const char *candidate = main_cmds.names[i]->name;
 300
 301                 /*
 302                  * An exact match means we have the command, but
 303                  * for some reason exec'ing it gave us ENOENT; probably
 304                  * it's a bad interpreter in the #! line.
 305                  */
 306                 if (!strcmp(candidate, cmd))
 307                         die(_(bad_interpreter_advice), cmd, cmd);
 308
 309                 /* Does the candidate appear in common_cmds list? */
 310                 while (n < ARRAY_SIZE(common_cmds) &&
 311                        (cmp = strcmp(common_cmds[n].name, candidate)) < 0)
 312                         n++;
 313                 if ((n < ARRAY_SIZE(common_cmds)) && !cmp) {
 314                         /* Yes, this is one of the common commands */
 315                         n++; /* use the entry from common_cmds[] */
 316                         if (!prefixcmp(candidate, cmd)) {
 317                                 /* Give prefix match a very good score */
 318                                 main_cmds.names[i]->len = 0;
 319                                 continue;
 320                         }
 321                 }
 322
 323                 main_cmds.names[i]->len =
 324                         levenshtein(cmd, candidate, 0, 2, 1, 3) + 1;
 325         }
 326
 327         qsort(main_cmds.names, main_cmds.cnt,
 328               sizeof(*main_cmds.names), levenshtein_compare);
 329
 330         if (!main_cmds.cnt)
 331                 die(_("Uh oh. Your system reports no Git commands at all."));
 332
 333         /* skip and count prefix matches */
 334         for (n = 0; n < main_cmds.cnt && !main_cmds.names[n]->len; n++)
 335                 ; /* still counting */
 336
 337         if (main_cmds.cnt <= n) {
 338                 /* prefix matches with everything? that is too ambiguous */
 339                 best_similarity = SIMILARITY_FLOOR + 1;
 340         } else {
 341                 /* count all the most similar ones */
 342                 for (best_similarity = main_cmds.names[n++]->len;
 343                      (n < main_cmds.cnt &&
 344                       best_similarity == main_cmds.names[n]->len);
 345                      n++)
 346                         ; /* still counting */
 347         }
 348         if (autocorrect && n == 1 && SIMILAR_ENOUGH(best_similarity)) {
 349                 const char *assumed = main_cmds.names[0]->name;
 350                 main_cmds.names[0] = NULL;
 351                 clean_cmdnames(&main_cmds);
 352                 fprintf_ln(stderr,
 353                            _("WARNING: You called a Git command named '%s', "
 354                              "which does not exist.\n"
 355                              "Continuing under the assumption that you meant '%s'"),
 356                         cmd, assumed);
 357                 if (autocorrect > 0) {
 358                         fprintf_ln(stderr, _("in %0.1f seconds automatically..."),
 359                                 (float)autocorrect/10.0);
 360                         poll(NULL, 0, autocorrect * 100);
 361                 }
 362                 return assumed;
 363         }
 364
 365         fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
 366
 367         if (SIMILAR_ENOUGH(best_similarity)) {
 368                 fprintf_ln(stderr,
 369                            Q_("\nDid you mean this?",
 370                               "\nDid you mean one of these?",
 371                            n));
 372
 373                 for (i = 0; i < n; i++)
 374                         fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
 375         }
 376
 377         exit(1);
 378 }
 379
 380 int cmd_version(int argc, const char **argv, const char *prefix)
 381 {
 382         printf("git version %s\n", git_version_string);
 383         return 0;
 384 }