builtin-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 static const char git_usage[] =
  13         "Usage: git [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ ARGS ]";
  14
  15 /* most GUI terminals set COLUMNS (although some don't export it) */
  16 static int term_columns(void)
  17 {
  18         char *col_string = getenv("COLUMNS");
  19         int n_cols = 0;
  20
  21         if (col_string && (n_cols = atoi(col_string)) > 0)
  22                 return n_cols;
  23
  24 #ifdef TIOCGWINSZ
  25         {
  26                 struct winsize ws;
  27                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
  28                         if (ws.ws_col)
  29                                 return ws.ws_col;
  30                 }
  31         }
  32 #endif
  33
  34         return 80;
  35 }
  36
  37 static void oom(void)
  38 {
  39         fprintf(stderr, "git: out of memory\n");
  40         exit(1);
  41 }
  42
  43 static inline void mput_char(char c, unsigned int num)
  44 {
  45         while(num--)
  46                 putchar(c);
  47 }
  48
  49 static struct cmdname {
  50         size_t len;
  51         char name[1];
  52 } **cmdname;
  53 static int cmdname_alloc, cmdname_cnt;
  54
  55 static void add_cmdname(const char *name, int len)
  56 {
  57         struct cmdname *ent;
  58         if (cmdname_alloc <= cmdname_cnt) {
  59                 cmdname_alloc = cmdname_alloc + 200;
  60                 cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname));
  61                 if (!cmdname)
  62                         oom();
  63         }
  64         ent = malloc(sizeof(*ent) + len);
  65         if (!ent)
  66                 oom();
  67         ent->len = len;
  68         memcpy(ent->name, name, len);
  69         ent->name[len] = 0;
  70         cmdname[cmdname_cnt++] = ent;
  71 }
  72
  73 static int cmdname_compare(const void *a_, const void *b_)
  74 {
  75         struct cmdname *a = *(struct cmdname **)a_;
  76         struct cmdname *b = *(struct cmdname **)b_;
  77         return strcmp(a->name, b->name);
  78 }
  79
  80 static void pretty_print_string_list(struct cmdname **cmdname, int longest)
  81 {
  82         int cols = 1, rows;
  83         int space = longest + 1; /* min 1 SP between words */
  84         int max_cols = term_columns() - 1; /* don't print *on* the edge */
  85         int i, j;
  86
  87         if (space < max_cols)
  88                 cols = max_cols / space;
  89         rows = (cmdname_cnt + cols - 1) / cols;
  90
  91         qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare);
  92
  93         for (i = 0; i < rows; i++) {
  94                 printf("  ");
  95
  96                 for (j = 0; j < cols; j++) {
  97                         int n = j * rows + i;
  98                         int size = space;
  99                         if (n >= cmdname_cnt)
 100                                 break;
 101                         if (j == cols-1 || n + rows >= cmdname_cnt)
 102                                 size = 1;
 103                         printf("%-*s", size, cmdname[n]->name);
 104                 }
 105                 putchar('\n');
 106         }
 107 }
 108
 109 static void list_commands(const char *exec_path, const char *pattern)
 110 {
 111         unsigned int longest = 0;
 112         char path[PATH_MAX];
 113         int dirlen;
 114         DIR *dir = opendir(exec_path);
 115         struct dirent *de;
 116
 117         if (!dir) {
 118                 fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
 119                 exit(1);
 120         }
 121
 122         dirlen = strlen(exec_path);
 123         if (PATH_MAX - 20 < dirlen) {
 124                 fprintf(stderr, "git: insanely long exec-path '%s'\n",
 125                         exec_path);
 126                 exit(1);
 127         }
 128
 129         memcpy(path, exec_path, dirlen);
 130         path[dirlen++] = '/';
 131
 132         while ((de = readdir(dir)) != NULL) {
 133                 struct stat st;
 134                 int entlen;
 135
 136                 if (strncmp(de->d_name, "git-", 4))
 137                         continue;
 138                 strcpy(path+dirlen, de->d_name);
 139                 if (stat(path, &st) || /* stat, not lstat */
 140                     !S_ISREG(st.st_mode) ||
 141                     !(st.st_mode & S_IXUSR))
 142                         continue;
 143
 144                 entlen = strlen(de->d_name);
 145                 if (4 < entlen && !strcmp(de->d_name + entlen - 4, ".exe"))
 146                         entlen -= 4;
 147
 148                 if (longest < entlen)
 149                         longest = entlen;
 150
 151                 add_cmdname(de->d_name + 4, entlen-4);
 152         }
 153         closedir(dir);
 154
 155         printf("git commands available in '%s'\n", exec_path);
 156         printf("----------------------------");
 157         mput_char('-', strlen(exec_path));
 158         putchar('\n');
 159         pretty_print_string_list(cmdname, longest - 4);
 160         putchar('\n');
 161 }
 162
 163 static void list_common_cmds_help(void)
 164 {
 165         int i, longest = 0;
 166
 167         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 168                 if (longest < strlen(common_cmds[i].name))
 169                         longest = strlen(common_cmds[i].name);
 170         }
 171
 172         puts("The most commonly used git commands are:");
 173         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 174                 printf("    %s", common_cmds[i].name);
 175                 mput_char(' ', longest - strlen(common_cmds[i].name) + 4);
 176                 puts(common_cmds[i].help);
 177         }
 178         puts("(use 'git help -a' to get a list of all installed git commands)");
 179 }
 180
 181 void cmd_usage(int show_all, const char *exec_path, const char *fmt, ...)
 182 {
 183         if (fmt) {
 184                 va_list ap;
 185
 186                 va_start(ap, fmt);
 187                 printf("git: ");
 188                 vprintf(fmt, ap);
 189                 va_end(ap);
 190                 putchar('\n');
 191         }
 192         else
 193                 puts(git_usage);
 194
 195         if (exec_path) {
 196                 putchar('\n');
 197                 if (show_all)
 198                         list_commands(exec_path, "git-*");
 199                 else
 200                         list_common_cmds_help();
 201         }
 202
 203         exit(1);
 204 }
 205
 206 static void show_man_page(const char *git_cmd)
 207 {
 208         const char *page;
 209
 210         if (!strncmp(git_cmd, "git", 3))
 211                 page = git_cmd;
 212         else {
 213                 int page_len = strlen(git_cmd) + 4;
 214                 char *p = malloc(page_len + 1);
 215                 strcpy(p, "git-");
 216                 strcpy(p + 4, git_cmd);
 217                 p[page_len] = 0;
 218                 page = p;
 219         }
 220
 221         execlp("man", "man", page, NULL);
 222 }
 223
 224 int cmd_version(int argc, const char **argv, char **envp)
 225 {
 226         printf("git version %s\n", git_version_string);
 227         return 0;
 228 }
 229
 230 int cmd_help(int argc, const char **argv, char **envp)
 231 {
 232         const char *help_cmd = argv[1];
 233         if (!help_cmd)
 234                 cmd_usage(0, git_exec_path(), NULL);
 235         else if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a"))
 236                 cmd_usage(1, git_exec_path(), NULL);
 237         else
 238                 show_man_page(help_cmd);
 239         return 0;
 240 }
 241
 242