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 void oom(void)
  35 {
  36         fprintf(stderr, "git: out of memory\n");
  37         exit(1);
  38 }
  39
  40 static inline void mput_char(char c, unsigned int num)
  41 {
  42         while(num--)
  43                 putchar(c);
  44 }
  45
  46 static struct cmdname {
  47         size_t len;
  48         char name[1];
  49 } **cmdname;
  50 static int cmdname_alloc, cmdname_cnt;
  51
  52 static void add_cmdname(const char *name, int len)
  53 {
  54         struct cmdname *ent;
  55         if (cmdname_alloc <= cmdname_cnt) {
  56                 cmdname_alloc = cmdname_alloc + 200;
  57                 cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname));
  58                 if (!cmdname)
  59                         oom();
  60         }
  61         ent = malloc(sizeof(*ent) + len);
  62         if (!ent)
  63                 oom();
  64         ent->len = len;
  65         memcpy(ent->name, name, len);
  66         ent->name[len] = 0;
  67         cmdname[cmdname_cnt++] = ent;
  68 }
  69
  70 static int cmdname_compare(const void *a_, const void *b_)
  71 {
  72         struct cmdname *a = *(struct cmdname **)a_;
  73         struct cmdname *b = *(struct cmdname **)b_;
  74         return strcmp(a->name, b->name);
  75 }
  76
  77 static void pretty_print_string_list(struct cmdname **cmdname, int longest)
  78 {
  79         int cols = 1, rows;
  80         int space = longest + 1; /* min 1 SP between words */
  81         int max_cols = term_columns() - 1; /* don't print *on* the edge */
  82         int i, j;
  83
  84         if (space < max_cols)
  85                 cols = max_cols / space;
  86         rows = (cmdname_cnt + cols - 1) / cols;
  87
  88         qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare);
  89
  90         for (i = 0; i < rows; i++) {
  91                 printf("  ");
  92
  93                 for (j = 0; j < cols; j++) {
  94                         int n = j * rows + i;
  95                         int size = space;
  96                         if (n >= cmdname_cnt)
  97                                 break;
  98                         if (j == cols-1 || n + rows >= cmdname_cnt)
  99                                 size = 1;
 100                         printf("%-*s", size, cmdname[n]->name);
 101                 }
 102                 putchar('\n');
 103         }
 104 }
 105
 106 static void list_commands(const char *exec_path, const char *pattern)
 107 {
 108         unsigned int longest = 0;
 109         char path[PATH_MAX];
 110         int dirlen;
 111         DIR *dir = opendir(exec_path);
 112         struct dirent *de;
 113
 114         if (!dir) {
 115                 fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
 116                 exit(1);
 117         }
 118
 119         dirlen = strlen(exec_path);
 120         if (PATH_MAX - 20 < dirlen) {
 121                 fprintf(stderr, "git: insanely long exec-path '%s'\n",
 122                         exec_path);
 123                 exit(1);
 124         }
 125
 126         memcpy(path, exec_path, dirlen);
 127         path[dirlen++] = '/';
 128
 129         while ((de = readdir(dir)) != NULL) {
 130                 struct stat st;
 131                 int entlen;
 132
 133                 if (strncmp(de->d_name, "git-", 4))
 134                         continue;
 135                 strcpy(path+dirlen, de->d_name);
 136                 if (stat(path, &st) || /* stat, not lstat */
 137                     !S_ISREG(st.st_mode) ||
 138                     !(st.st_mode & S_IXUSR))
 139                         continue;
 140
 141                 entlen = strlen(de->d_name);
 142                 if (has_extension(de->d_name, ".exe"))
 143                         entlen -= 4;
 144
 145                 if (longest < entlen)
 146                         longest = entlen;
 147
 148                 add_cmdname(de->d_name + 4, entlen-4);
 149         }
 150         closedir(dir);
 151
 152         printf("git commands available in '%s'\n", exec_path);
 153         printf("----------------------------");
 154         mput_char('-', strlen(exec_path));
 155         putchar('\n');
 156         pretty_print_string_list(cmdname, longest - 4);
 157         putchar('\n');
 158 }
 159
 160 static void list_common_cmds_help(void)
 161 {
 162         int i, longest = 0;
 163
 164         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 165                 if (longest < strlen(common_cmds[i].name))
 166                         longest = strlen(common_cmds[i].name);
 167         }
 168
 169         puts("The most commonly used git commands are:");
 170         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 171                 printf("    %s", common_cmds[i].name);
 172                 mput_char(' ', longest - strlen(common_cmds[i].name) + 4);
 173                 puts(common_cmds[i].help);
 174         }
 175         puts("(use 'git help -a' to get a list of all installed git commands)");
 176 }
 177
 178 static void show_man_page(const char *git_cmd)
 179 {
 180         const char *page;
 181
 182         if (!strncmp(git_cmd, "git", 3))
 183                 page = git_cmd;
 184         else {
 185                 int page_len = strlen(git_cmd) + 4;
 186                 char *p = xmalloc(page_len + 1);
 187                 strcpy(p, "git-");
 188                 strcpy(p + 4, git_cmd);
 189                 p[page_len] = 0;
 190                 page = p;
 191         }
 192
 193         execlp("man", "man", page, NULL);
 194 }
 195
 196 void help_unknown_cmd(const char *cmd)
 197 {
 198         printf("git: '%s' is not a git-command\n\n", cmd);
 199         list_common_cmds_help();
 200         exit(1);
 201 }
 202
 203 int cmd_version(int argc, const char **argv, const char *prefix)
 204 {
 205         printf("git version %s\n", git_version_string);
 206         return 0;
 207 }
 208
 209 int cmd_help(int argc, const char **argv, const char *prefix)
 210 {
 211         const char *help_cmd = argc > 1 ? argv[1] : NULL;
 212         const char *exec_path = git_exec_path();
 213
 214         if (!help_cmd) {
 215                 printf("usage: %s\n\n", git_usage_string);
 216                 list_common_cmds_help();
 217                 exit(1);
 218         }
 219
 220         else if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
 221                 printf("usage: %s\n\n", git_usage_string);
 222                 if(exec_path)
 223                         list_commands(exec_path, "git-*");
 224                 exit(1);
 225         }
 226
 227         else
 228                 show_man_page(help_cmd);
 229
 230         return 0;
 231 }
 232
 233