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