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