help.c

   1 /*
   2  * builtin-help.c
   3  *
   4  * Builtin help-related commands (help, usage, version)
   5  */
   6 #include "cache.h"
   7 #include "builtin.h"
   8 #include "exec_cmd.h"
   9 #include "common-cmds.h"
  10 #include <sys/ioctl.h>
  11
  12 /* most GUI terminals set COLUMNS (although some don't export it) */
  13 static int term_columns(void)
  14 {
  15         char *col_string = getenv("COLUMNS");
  16         int n_cols;
  17
  18         if (col_string && (n_cols = atoi(col_string)) > 0)
  19                 return n_cols;
  20
  21 #ifdef TIOCGWINSZ
  22         {
  23                 struct winsize ws;
  24                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
  25                         if (ws.ws_col)
  26                                 return ws.ws_col;
  27                 }
  28         }
  29 #endif
  30
  31         return 80;
  32 }
  33
  34 static inline void mput_char(char c, unsigned int num)
  35 {
  36         while(num--)
  37                 putchar(c);
  38 }
  39
  40 static struct cmdnames {
  41         int alloc;
  42         int cnt;
  43         struct cmdname {
  44                 size_t len;
  45                 char name[1];
  46         } **names;
  47 } main_cmds, other_cmds;
  48
  49 static void add_cmdname(struct cmdnames *cmds, const char *name, int len)
  50 {
  51         struct cmdname *ent = xmalloc(sizeof(*ent) + len);
  52
  53         ent->len = len;
  54         memcpy(ent->name, name, len);
  55         ent->name[len] = 0;
  56
  57         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
  58         cmds->names[cmds->cnt++] = ent;
  59 }
  60
  61 static int cmdname_compare(const void *a_, const void *b_)
  62 {
  63         struct cmdname *a = *(struct cmdname **)a_;
  64         struct cmdname *b = *(struct cmdname **)b_;
  65         return strcmp(a->name, b->name);
  66 }
  67
  68 static void uniq(struct cmdnames *cmds)
  69 {
  70         int i, j;
  71
  72         if (!cmds->cnt)
  73                 return;
  74
  75         for (i = j = 1; i < cmds->cnt; i++)
  76                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
  77                         cmds->names[j++] = cmds->names[i];
  78
  79         cmds->cnt = j;
  80 }
  81
  82 static void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes) {
  83         int ci, cj, ei;
  84         int cmp;
  85
  86         ci = cj = ei = 0;
  87         while (ci < cmds->cnt && ei < excludes->cnt) {
  88                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
  89                 if (cmp < 0)
  90                         cmds->names[cj++] = cmds->names[ci++];
  91                 else if (cmp == 0)
  92                         ci++, ei++;
  93                 else if (cmp > 0)
  94                         ei++;
  95         }
  96
  97         while (ci < cmds->cnt)
  98                 cmds->names[cj++] = cmds->names[ci++];
  99
 100         cmds->cnt = cj;
 101 }
 102
 103 static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 104 {
 105         int cols = 1, rows;
 106         int space = longest + 1; /* min 1 SP between words */
 107         int max_cols = term_columns() - 1; /* don't print *on* the edge */
 108         int i, j;
 109
 110         if (space < max_cols)
 111                 cols = max_cols / space;
 112         rows = (cmds->cnt + cols - 1) / cols;
 113
 114         for (i = 0; i < rows; i++) {
 115                 printf("  ");
 116
 117                 for (j = 0; j < cols; j++) {
 118                         int n = j * rows + i;
 119                         int size = space;
 120                         if (n >= cmds->cnt)
 121                                 break;
 122                         if (j == cols-1 || n + rows >= cmds->cnt)
 123                                 size = 1;
 124                         printf("%-*s", size, cmds->names[n]->name);
 125                 }
 126                 putchar('\n');
 127         }
 128 }
 129
 130 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 131                                          const char *path)
 132 {
 133         unsigned int longest = 0;
 134         const char *prefix = "git-";
 135         int prefix_len = strlen(prefix);
 136         DIR *dir = opendir(path);
 137         struct dirent *de;
 138
 139         if (!dir || chdir(path))
 140                 return 0;
 141
 142         while ((de = readdir(dir)) != NULL) {
 143                 struct stat st;
 144                 int entlen;
 145
 146                 if (prefixcmp(de->d_name, prefix))
 147                         continue;
 148
 149                 if (stat(de->d_name, &st) || /* stat, not lstat */
 150                     !S_ISREG(st.st_mode) ||
 151                     !(st.st_mode & S_IXUSR))
 152                         continue;
 153
 154                 entlen = strlen(de->d_name) - prefix_len;
 155                 if (has_extension(de->d_name, ".exe"))
 156                         entlen -= 4;
 157
 158                 if (longest < entlen)
 159                         longest = entlen;
 160
 161                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 162         }
 163         closedir(dir);
 164
 165         return longest;
 166 }
 167
 168 static void list_commands(void)
 169 {
 170         unsigned int longest = 0;
 171         unsigned int len;
 172         const char *env_path = getenv("PATH");
 173         char *paths, *path, *colon;
 174         const char *exec_path = git_exec_path();
 175
 176         if (exec_path)
 177                 longest = list_commands_in_dir(&main_cmds, exec_path);
 178
 179         if (!env_path) {
 180                 fprintf(stderr, "PATH not set\n");
 181                 exit(1);
 182         }
 183
 184         path = paths = xstrdup(env_path);
 185         while (1) {
 186                 if ((colon = strchr(path, ':')))
 187                         *colon = 0;
 188
 189                 len = list_commands_in_dir(&other_cmds, path);
 190                 if (len > longest)
 191                         longest = len;
 192
 193                 if (!colon)
 194                         break;
 195                 path = colon + 1;
 196         }
 197         free(paths);
 198
 199         qsort(main_cmds.names, main_cmds.cnt,
 200               sizeof(*main_cmds.names), cmdname_compare);
 201         uniq(&main_cmds);
 202
 203         qsort(other_cmds.names, other_cmds.cnt,
 204               sizeof(*other_cmds.names), cmdname_compare);
 205         uniq(&other_cmds);
 206         exclude_cmds(&other_cmds, &main_cmds);
 207
 208         if (main_cmds.cnt) {
 209                 printf("available git commands in '%s'\n", exec_path);
 210                 printf("----------------------------");
 211                 mput_char('-', strlen(exec_path));
 212                 putchar('\n');
 213                 pretty_print_string_list(&main_cmds, longest);
 214                 putchar('\n');
 215         }
 216
 217         if (other_cmds.cnt) {
 218                 printf("git commands available from elsewhere on your $PATH\n");
 219                 printf("---------------------------------------------------\n");
 220                 pretty_print_string_list(&other_cmds, longest);
 221                 putchar('\n');
 222         }
 223 }
 224
 225 void list_common_cmds_help(void)
 226 {
 227         int i, longest = 0;
 228
 229         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 230                 if (longest < strlen(common_cmds[i].name))
 231                         longest = strlen(common_cmds[i].name);
 232         }
 233
 234         puts("The most commonly used git commands are:");
 235         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 236                 printf("   %s   ", common_cmds[i].name);
 237                 mput_char(' ', longest - strlen(common_cmds[i].name));
 238                 puts(common_cmds[i].help);
 239         }
 240         puts("(use 'git help -a' to get a list of all installed git commands)");
 241 }
 242
 243 static void show_man_page(const char *git_cmd)
 244 {
 245         const char *page;
 246
 247         if (!prefixcmp(git_cmd, "git"))
 248                 page = git_cmd;
 249         else {
 250                 int page_len = strlen(git_cmd) + 4;
 251                 char *p = xmalloc(page_len + 1);
 252                 strcpy(p, "git-");
 253                 strcpy(p + 4, git_cmd);
 254                 p[page_len] = 0;
 255                 page = p;
 256         }
 257
 258         execlp("man", "man", page, NULL);
 259 }
 260
 261 void help_unknown_cmd(const char *cmd)
 262 {
 263         fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
 264         exit(1);
 265 }
 266
 267 int cmd_version(int argc, const char **argv, const char *prefix)
 268 {
 269         printf("git version %s\n", git_version_string);
 270         return 0;
 271 }
 272
 273 int cmd_help(int argc, const char **argv, const char *prefix)
 274 {
 275         const char *help_cmd = argc > 1 ? argv[1] : NULL;
 276
 277         if (!help_cmd) {
 278                 printf("usage: %s\n\n", git_usage_string);
 279                 list_common_cmds_help();
 280                 exit(0);
 281         }
 282
 283         else if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
 284                 printf("usage: %s\n\n", git_usage_string);
 285                 list_commands();
 286                 exit(0);
 287         }
 288
 289         else
 290                 show_man_page(help_cmd);
 291
 292         return 0;
 293 }