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, const char *pattern)
  97 {
  98         unsigned int longest = 0;
  99         char path[PATH_MAX];
 100         int dirlen;
 101         DIR *dir = opendir(exec_path);
 102         struct dirent *de;
 103
 104         if (!dir) {
 105                 fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
 106                 exit(1);
 107         }
 108
 109         dirlen = strlen(exec_path);
 110         if (PATH_MAX - 20 < dirlen) {
 111                 fprintf(stderr, "git: insanely long exec-path '%s'\n",
 112                         exec_path);
 113                 exit(1);
 114         }
 115
 116         memcpy(path, exec_path, dirlen);
 117         path[dirlen++] = '/';
 118
 119         while ((de = readdir(dir)) != NULL) {
 120                 struct stat st;
 121                 int entlen;
 122
 123                 if (prefixcmp(de->d_name, "git-"))
 124                         continue;
 125                 strcpy(path+dirlen, de->d_name);
 126                 if (stat(path, &st) || /* stat, not lstat */
 127                     !S_ISREG(st.st_mode) ||
 128                     !(st.st_mode & S_IXUSR))
 129                         continue;
 130
 131                 entlen = strlen(de->d_name);
 132                 if (has_extension(de->d_name, ".exe"))
 133                         entlen -= 4;
 134
 135                 if (longest < entlen)
 136                         longest = entlen;
 137
 138                 add_cmdname(de->d_name + 4, entlen-4);
 139         }
 140         closedir(dir);
 141
 142         printf("git commands available in '%s'\n", exec_path);
 143         printf("----------------------------");
 144         mput_char('-', strlen(exec_path));
 145         putchar('\n');
 146         pretty_print_string_list(cmdname, longest - 4);
 147         putchar('\n');
 148 }
 149
 150 static void list_common_cmds_help(void)
 151 {
 152         int i, longest = 0;
 153
 154         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 155                 if (longest < strlen(common_cmds[i].name))
 156                         longest = strlen(common_cmds[i].name);
 157         }
 158
 159         puts("The most commonly used git commands are:");
 160         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 161                 printf("   %s   ", common_cmds[i].name);
 162                 mput_char(' ', longest - strlen(common_cmds[i].name));
 163                 puts(common_cmds[i].help);
 164         }
 165         puts("(use 'git help -a' to get a list of all installed git commands)");
 166 }
 167
 168 static void show_man_page(const char *git_cmd)
 169 {
 170         const char *page;
 171
 172         if (!prefixcmp(git_cmd, "git"))
 173                 page = git_cmd;
 174         else {
 175                 int page_len = strlen(git_cmd) + 4;
 176                 char *p = xmalloc(page_len + 1);
 177                 strcpy(p, "git-");
 178                 strcpy(p + 4, git_cmd);
 179                 p[page_len] = 0;
 180                 page = p;
 181         }
 182
 183         execlp("man", "man", page, NULL);
 184 }
 185
 186 void help_unknown_cmd(const char *cmd)
 187 {
 188         printf("git: '%s' is not a git-command\n\n", cmd);
 189         list_common_cmds_help();
 190         exit(1);
 191 }
 192
 193 int cmd_version(int argc, const char **argv, const char *prefix)
 194 {
 195         printf("git version %s\n", git_version_string);
 196         return 0;
 197 }
 198
 199 int cmd_help(int argc, const char **argv, const char *prefix)
 200 {
 201         const char *help_cmd = argc > 1 ? argv[1] : NULL;
 202         const char *exec_path = git_exec_path();
 203
 204         if (!help_cmd) {
 205                 printf("usage: %s\n\n", git_usage_string);
 206                 list_common_cmds_help();
 207                 exit(1);
 208         }
 209
 210         else if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
 211                 printf("usage: %s\n\n", git_usage_string);
 212                 if(exec_path)
 213                         list_commands(exec_path, "git-*");
 214                 exit(1);
 215         }
 216
 217         else
 218                 show_man_page(help_cmd);
 219
 220         return 0;
 221 }