help.c

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