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