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
  10 void add_cmdname(struct cmdnames *cmds, const char *name, int len)
  11 {
  12         struct cmdname *ent = xmalloc(sizeof(*ent) + len + 1);
  13
  14         ent->len = len;
  15         memcpy(ent->name, name, len);
  16         ent->name[len] = 0;
  17
  18         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
  19         cmds->names[cmds->cnt++] = ent;
  20 }
  21
  22 static void clean_cmdnames(struct cmdnames *cmds)
  23 {
  24         int i;
  25         for (i = 0; i < cmds->cnt; ++i)
  26                 free(cmds->names[i]);
  27         free(cmds->names);
  28         cmds->cnt = 0;
  29         cmds->alloc = 0;
  30 }
  31
  32 static int cmdname_compare(const void *a_, const void *b_)
  33 {
  34         struct cmdname *a = *(struct cmdname **)a_;
  35         struct cmdname *b = *(struct cmdname **)b_;
  36         return strcmp(a->name, b->name);
  37 }
  38
  39 static void uniq(struct cmdnames *cmds)
  40 {
  41         int i, j;
  42
  43         if (!cmds->cnt)
  44                 return;
  45
  46         for (i = j = 1; i < cmds->cnt; i++)
  47                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
  48                         cmds->names[j++] = cmds->names[i];
  49
  50         cmds->cnt = j;
  51 }
  52
  53 void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
  54 {
  55         int ci, cj, ei;
  56         int cmp;
  57
  58         ci = cj = ei = 0;
  59         while (ci < cmds->cnt && ei < excludes->cnt) {
  60                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
  61                 if (cmp < 0)
  62                         cmds->names[cj++] = cmds->names[ci++];
  63                 else if (cmp == 0)
  64                         ci++, ei++;
  65                 else if (cmp > 0)
  66                         ei++;
  67         }
  68
  69         while (ci < cmds->cnt)
  70                 cmds->names[cj++] = cmds->names[ci++];
  71
  72         cmds->cnt = cj;
  73 }
  74
  75 static void pretty_print_string_list(struct cmdnames *cmds,
  76                                      unsigned int colopts)
  77 {
  78         struct string_list list = STRING_LIST_INIT_NODUP;
  79         struct column_options copts;
  80         int i;
  81
  82         for (i = 0; i < cmds->cnt; i++)
  83                 string_list_append(&list, cmds->names[i]->name);
  84         /*
  85          * always enable column display, we only consult column.*
  86          * about layout strategy and stuff
  87          */
  88         colopts = (colopts & ~COL_ENABLE_MASK) | COL_ENABLED;
  89         memset(&copts, 0, sizeof(copts));
  90         copts.indent = "  ";
  91         copts.padding = 2;
  92         print_columns(&list, colopts, &copts);
  93         string_list_clear(&list, 0);
  94 }
  95
  96 static int is_executable(const char *name)
  97 {
  98         struct stat st;
  99
 100         if (stat(name, &st) || /* stat, not lstat */
 101             !S_ISREG(st.st_mode))
 102                 return 0;
 103
 104 #if defined(WIN32) || defined(__CYGWIN__)
 105 #if defined(__CYGWIN__)
 106 if ((st.st_mode & S_IXUSR) == 0)
 107 #endif
 108 {       /* cannot trust the executable bit, peek into the file instead */
 109         char buf[3] = { 0 };
 110         int n;
 111         int fd = open(name, O_RDONLY);
 112         st.st_mode &= ~S_IXUSR;
 113         if (fd >= 0) {
 114                 n = read(fd, buf, 2);
 115                 if (n == 2)
 116                         /* DOS executables start with "MZ" */
 117                         if (!strcmp(buf, "#!") || !strcmp(buf, "MZ"))
 118                                 st.st_mode |= S_IXUSR;
 119                 close(fd);
 120         }
 121 }
 122 #endif
 123         return st.st_mode & S_IXUSR;
 124 }
 125
 126 static void list_commands_in_dir(struct cmdnames *cmds,
 127                                          const char *path,
 128                                          const char *prefix)
 129 {
 130         int prefix_len;
 131         DIR *dir = opendir(path);
 132         struct dirent *de;
 133         struct strbuf buf = STRBUF_INIT;
 134         int len;
 135
 136         if (!dir)
 137                 return;
 138         if (!prefix)
 139                 prefix = "git-";
 140         prefix_len = strlen(prefix);
 141
 142         strbuf_addf(&buf, "%s/", path);
 143         len = buf.len;
 144
 145         while ((de = readdir(dir)) != NULL) {
 146                 int entlen;
 147
 148                 if (prefixcmp(de->d_name, prefix))
 149                         continue;
 150
 151                 strbuf_setlen(&buf, len);
 152                 strbuf_addstr(&buf, de->d_name);
 153                 if (!is_executable(buf.buf))
 154                         continue;
 155
 156                 entlen = strlen(de->d_name) - prefix_len;
 157                 if (has_extension(de->d_name, ".exe"))
 158                         entlen -= 4;
 159
 160                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 161         }
 162         closedir(dir);
 163         strbuf_release(&buf);
 164 }
 165
 166 void load_command_list(const char *prefix,
 167                 struct cmdnames *main_cmds,
 168                 struct cmdnames *other_cmds)
 169 {
 170         const char *env_path = getenv("PATH");
 171         const char *exec_path = git_exec_path();
 172
 173         if (exec_path) {
 174                 list_commands_in_dir(main_cmds, exec_path, prefix);
 175                 qsort(main_cmds->names, main_cmds->cnt,
 176                       sizeof(*main_cmds->names), cmdname_compare);
 177                 uniq(main_cmds);
 178         }
 179
 180         if (env_path) {
 181                 char *paths, *path, *colon;
 182                 path = paths = xstrdup(env_path);
 183                 while (1) {
 184                         if ((colon = strchr(path, PATH_SEP)))
 185                                 *colon = 0;
 186                         if (!exec_path || strcmp(path, exec_path))
 187                                 list_commands_in_dir(other_cmds, path, prefix);
 188
 189                         if (!colon)
 190                                 break;
 191                         path = colon + 1;
 192                 }
 193                 free(paths);
 194
 195                 qsort(other_cmds->names, other_cmds->cnt,
 196                       sizeof(*other_cmds->names), cmdname_compare);
 197                 uniq(other_cmds);
 198         }
 199         exclude_cmds(other_cmds, main_cmds);
 200 }
 201
 202 void list_commands(const char *title, unsigned int colopts,
 203                    struct cmdnames *main_cmds, struct cmdnames *other_cmds)
 204 {
 205         if (main_cmds->cnt) {
 206                 const char *exec_path = git_exec_path();
 207                 printf("available %s in '%s'\n", title, exec_path);
 208                 printf("----------------");
 209                 mput_char('-', strlen(title) + strlen(exec_path));
 210                 putchar('\n');
 211                 pretty_print_string_list(main_cmds, colopts);
 212                 putchar('\n');
 213         }
 214
 215         if (other_cmds->cnt) {
 216                 printf("%s available from elsewhere on your $PATH\n", title);
 217                 printf("---------------------------------------");
 218                 mput_char('-', strlen(title));
 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, 4) + 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(stderr, "WARNING: You called a Git command named '%s', "
 353                         "which does not exist.\n"
 354                         "Continuing under the assumption that you meant '%s'\n",
 355                         cmd, assumed);
 356                 if (autocorrect > 0) {
 357                         fprintf(stderr, "in %0.1f seconds automatically...\n",
 358                                 (float)autocorrect/10.0);
 359                         poll(NULL, 0, autocorrect * 100);
 360                 }
 361                 return assumed;
 362         }
 363
 364         fprintf(stderr, "git: '%s' is not a git command. See 'git --help'.\n", cmd);
 365
 366         if (SIMILAR_ENOUGH(best_similarity)) {
 367                 fprintf(stderr, "\nDid you mean %s?\n",
 368                         n < 2 ? "this": "one of these");
 369
 370                 for (i = 0; i < n; i++)
 371                         fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
 372         }
 373
 374         exit(1);
 375 }
 376
 377 int cmd_version(int argc, const char **argv, const char *prefix)
 378 {
 379         printf("git version %s\n", git_version_string);
 380         return 0;
 381 }