help.c

   1 /*
   2  * builtin-help.c
   3  *
   4  * Builtin help-related commands (help, usage, version)
   5  */
   6 #include <sys/ioctl.h>
   7 #include "cache.h"
   8 #include "builtin.h"
   9 #include "exec_cmd.h"
  10 #include "common-cmds.h"
  11
  12
  13 /* most GUI terminals set COLUMNS (although some don't export it) */
  14 static int term_columns(void)
  15 {
  16         char *col_string = getenv("COLUMNS");
  17         int n_cols;
  18
  19         if (col_string && (n_cols = atoi(col_string)) > 0)
  20                 return n_cols;
  21
  22 #ifdef TIOCGWINSZ
  23         {
  24                 struct winsize ws;
  25                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
  26                         if (ws.ws_col)
  27                                 return ws.ws_col;
  28                 }
  29         }
  30 #endif
  31
  32         return 80;
  33 }
  34
  35 static void oom(void)
  36 {
  37         fprintf(stderr, "git: out of memory\n");
  38         exit(1);
  39 }
  40
  41 static inline void mput_char(char c, unsigned int num)
  42 {
  43         while(num--)
  44                 putchar(c);
  45 }
  46
  47 static struct cmdname {
  48         size_t len;
  49         char name[1];
  50 } **cmdname;
  51 static int cmdname_alloc, cmdname_cnt;
  52
  53 static void add_cmdname(const char *name, int len)
  54 {
  55         struct cmdname *ent;
  56         if (cmdname_alloc <= cmdname_cnt) {
  57                 cmdname_alloc = cmdname_alloc + 200;
  58                 cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname));
  59                 if (!cmdname)
  60                         oom();
  61         }
  62         ent = malloc(sizeof(*ent) + len);
  63         if (!ent)
  64                 oom();
  65         ent->len = len;
  66         memcpy(ent->name, name, len);
  67         ent->name[len] = 0;
  68         cmdname[cmdname_cnt++] = ent;
  69 }
  70
  71 static int cmdname_compare(const void *a_, const void *b_)
  72 {
  73         struct cmdname *a = *(struct cmdname **)a_;
  74         struct cmdname *b = *(struct cmdname **)b_;
  75         return strcmp(a->name, b->name);
  76 }
  77
  78 static void pretty_print_string_list(struct cmdname **cmdname, int longest)
  79 {
  80         int cols = 1, rows;
  81         int space = longest + 1; /* min 1 SP between words */
  82         int max_cols = term_columns() - 1; /* don't print *on* the edge */
  83         int i, j;
  84
  85         if (space < max_cols)
  86                 cols = max_cols / space;
  87         rows = (cmdname_cnt + cols - 1) / cols;
  88
  89         qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare);
  90
  91         for (i = 0; i < rows; i++) {
  92                 printf("  ");
  93
  94                 for (j = 0; j < cols; j++) {
  95                         int n = j * rows + i;
  96                         int size = space;
  97                         if (n >= cmdname_cnt)
  98                                 break;
  99                         if (j == cols-1 || n + rows >= cmdname_cnt)
 100                                 size = 1;
 101                         printf("%-*s", size, cmdname[n]->name);
 102                 }
 103                 putchar('\n');
 104         }
 105 }
 106
 107 static void list_commands(const char *exec_path, const char *pattern)
 108 {
 109         unsigned int longest = 0;
 110         char path[PATH_MAX];
 111         int dirlen;
 112         DIR *dir = opendir(exec_path);
 113         struct dirent *de;
 114
 115         if (!dir) {
 116                 fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
 117                 exit(1);
 118         }
 119
 120         dirlen = strlen(exec_path);
 121         if (PATH_MAX - 20 < dirlen) {
 122                 fprintf(stderr, "git: insanely long exec-path '%s'\n",
 123                         exec_path);
 124                 exit(1);
 125         }
 126
 127         memcpy(path, exec_path, dirlen);
 128         path[dirlen++] = '/';
 129
 130         while ((de = readdir(dir)) != NULL) {
 131                 struct stat st;
 132                 int entlen;
 133
 134                 if (strncmp(de->d_name, "git-", 4))
 135                         continue;
 136                 strcpy(path+dirlen, de->d_name);
 137                 if (stat(path, &st) || /* stat, not lstat */
 138                     !S_ISREG(st.st_mode) ||
 139                     !(st.st_mode & S_IXUSR))
 140                         continue;
 141
 142                 entlen = strlen(de->d_name);
 143                 if (has_extension(de->d_name, ".exe"))
 144                         entlen -= 4;
 145
 146                 if (longest < entlen)
 147                         longest = entlen;
 148
 149                 add_cmdname(de->d_name + 4, entlen-4);
 150         }
 151         closedir(dir);
 152
 153         printf("git commands available in '%s'\n", exec_path);
 154         printf("----------------------------");
 155         mput_char('-', strlen(exec_path));
 156         putchar('\n');
 157         pretty_print_string_list(cmdname, longest - 4);
 158         putchar('\n');
 159 }
 160
 161 static void list_common_cmds_help(void)
 162 {
 163         int i, longest = 0;
 164
 165         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 166                 if (longest < strlen(common_cmds[i].name))
 167                         longest = strlen(common_cmds[i].name);
 168         }
 169
 170         puts("The most commonly used git commands are:");
 171         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 172                 printf("    %s", common_cmds[i].name);
 173                 mput_char(' ', longest - strlen(common_cmds[i].name) + 4);
 174                 puts(common_cmds[i].help);
 175         }
 176         puts("(use 'git help -a' to get a list of all installed git commands)");
 177 }
 178
 179 static void show_man_page(const char *git_cmd)
 180 {
 181         const char *page;
 182
 183         if (!strncmp(git_cmd, "git", 3))
 184                 page = git_cmd;
 185         else {
 186                 int page_len = strlen(git_cmd) + 4;
 187                 char *p = xmalloc(page_len + 1);
 188                 strcpy(p, "git-");
 189                 strcpy(p + 4, git_cmd);
 190                 p[page_len] = 0;
 191                 page = p;
 192         }
 193
 194         execlp("man", "man", page, NULL);
 195 }
 196
 197 void help_unknown_cmd(const char *cmd)
 198 {
 199         printf("git: '%s' is not a git-command\n\n", cmd);
 200         list_common_cmds_help();
 201         exit(1);
 202 }
 203
 204 int cmd_version(int argc, const char **argv, const char *prefix)
 205 {
 206         printf("git version %s\n", git_version_string);
 207         return 0;
 208 }
 209
 210 int cmd_help(int argc, const char **argv, const char *prefix)
 211 {
 212         const char *help_cmd = argc > 1 ? argv[1] : NULL;
 213         const char *exec_path = git_exec_path();
 214
 215         if (!help_cmd) {
 216                 printf("usage: %s\n\n", git_usage_string);
 217                 list_common_cmds_help();
 218                 exit(1);
 219         }
 220
 221         else if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
 222                 printf("usage: %s\n\n", git_usage_string);
 223                 if(exec_path)
 224                         list_commands(exec_path, "git-*");
 225                 exit(1);
 226         }
 227
 228         else
 229                 show_man_page(help_cmd);
 230
 231         return 0;
 232 }
 233
 234