help.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public
   4  * License v2 as published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   9  * General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public
  12  * License along with this program; if not, write to the
  13  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14  * Boston, MA 021110-1307, USA.
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <limits.h>
  21
  22 #include "commands.h"
  23 #include "utils.h"
  24
  25 #define USAGE_SHORT             1U
  26 #define USAGE_LONG              2U
  27 #define USAGE_OPTIONS           4U
  28 #define USAGE_LISTING           8U
  29
  30 static int do_usage_one_command(const char * const *usagestr,
  31                                 unsigned int flags, FILE *outf)
  32 {
  33         int pad = 4;
  34
  35         if (!usagestr || !*usagestr)
  36                 return -1;
  37
  38         fprintf(outf, "%s%s\n", (flags & USAGE_LISTING) ? "    " : "usage: ",
  39                 *usagestr++);
  40
  41         /* a short one-line description (mandatory) */
  42         if ((flags & USAGE_SHORT) == 0)
  43                 return 0;
  44         else if (!*usagestr)
  45                 return -2;
  46
  47         if (flags & USAGE_LISTING)
  48                 pad = 8;
  49         else
  50                 fputc('\n', outf);
  51
  52         fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
  53
  54         /* a long (possibly multi-line) description (optional) */
  55         if (!*usagestr || ((flags & USAGE_LONG) == 0))
  56                 return 0;
  57
  58         if (**usagestr)
  59                 fputc('\n', outf);
  60         while (*usagestr && **usagestr)
  61                 fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
  62
  63         /* options (optional) */
  64         if (!*usagestr || ((flags & USAGE_OPTIONS) == 0))
  65                 return 0;
  66
  67         /*
  68          * options (if present) should always (even if there is no long
  69          * description) be prepended with an empty line, skip it
  70          */
  71         usagestr++;
  72
  73         fputc('\n', outf);
  74         while (*usagestr)
  75                 fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
  76
  77         return 0;
  78 }
  79
  80 static int usage_command_internal(const char * const *usagestr,
  81                                   const char *token, int full, int lst,
  82                                   FILE *outf)
  83 {
  84         unsigned int flags = USAGE_SHORT;
  85         int ret;
  86
  87         if (full)
  88                 flags |= USAGE_LONG | USAGE_OPTIONS;
  89         if (lst)
  90                 flags |= USAGE_LISTING;
  91
  92         ret = do_usage_one_command(usagestr, flags, outf);
  93         switch (ret) {
  94         case -1:
  95                 fprintf(outf, "No usage for '%s'\n", token);
  96                 break;
  97         case -2:
  98                 fprintf(outf, "No short description for '%s'\n", token);
  99                 break;
 100         }
 101
 102         return ret;
 103 }
 104
 105 static void usage_command_usagestr(const char * const *usagestr,
 106                                    const char *token, int full, int err)
 107 {
 108         FILE *outf = err ? stderr : stdout;
 109         int ret;
 110
 111         ret = usage_command_internal(usagestr, token, full, 0, outf);
 112         if (!ret)
 113                 fputc('\n', outf);
 114 }
 115
 116 void usage_command(const struct cmd_struct *cmd, int full, int err)
 117 {
 118         usage_command_usagestr(cmd->usagestr, cmd->token, full, err);
 119 }
 120
 121 void usage(const char * const *usagestr)
 122 {
 123         usage_command_usagestr(usagestr, NULL, 1, 1);
 124         exit(1);
 125 }
 126
 127 static void usage_command_group_internal(const struct cmd_group *grp, int full,
 128                                          FILE *outf)
 129 {
 130         const struct cmd_struct *cmd = grp->commands;
 131         int do_sep = 0;
 132
 133         for (; cmd->token; cmd++) {
 134                 if (cmd->flags & CMD_HIDDEN)
 135                         continue;
 136
 137                 if (full && cmd != grp->commands)
 138                         fputc('\n', outf);
 139
 140                 if (!cmd->next) {
 141                         if (do_sep) {
 142                                 fputc('\n', outf);
 143                                 do_sep = 0;
 144                         }
 145
 146                         usage_command_internal(cmd->usagestr, cmd->token, full,
 147                                                1, outf);
 148                         continue;
 149                 }
 150
 151                 /* this is an entry point to a nested command group */
 152
 153                 if (!full && cmd != grp->commands)
 154                         fputc('\n', outf);
 155
 156                 usage_command_group_internal(cmd->next, full, outf);
 157
 158                 if (!full)
 159                         do_sep = 1;
 160         }
 161 }
 162
 163 void usage_command_group_short(const struct cmd_group *grp)
 164 {
 165         const char * const *usagestr = grp->usagestr;
 166         FILE *outf = stdout;
 167         const struct cmd_struct *cmd;
 168
 169         if (usagestr && *usagestr) {
 170                 fprintf(outf, "usage: %s\n", *usagestr++);
 171                 while (*usagestr)
 172                         fprintf(outf, "   or: %s\n", *usagestr++);
 173         }
 174
 175         fputc('\n', outf);
 176
 177         fprintf(outf, "Command groups:\n");
 178         for (cmd = grp->commands; cmd->token; cmd++) {
 179                 if (cmd->flags & CMD_HIDDEN)
 180                         continue;
 181
 182                 if (!cmd->next)
 183                         continue;
 184
 185                 fprintf(outf, "  %-16s  %s\n", cmd->token, cmd->next->infostr);
 186         }
 187
 188         fprintf(outf, "\nCommands:\n");
 189         for (cmd = grp->commands; cmd->token; cmd++) {
 190                 if (cmd->flags & CMD_HIDDEN)
 191                         continue;
 192
 193                 if (cmd->next)
 194                         continue;
 195
 196                 fprintf(outf, "  %-16s  %s\n", cmd->token, cmd->usagestr[1]);
 197         }
 198
 199         fputc('\n', outf);
 200         fprintf(stderr, "For an overview of a given command use 'btrfs command --help'\n");
 201         fprintf(stderr, "or 'btrfs [command...] --help --full' to print all available options.\n");
 202         fprintf(stderr, "Any command name can be shortened as far as it stays unambiguous,\n");
 203         fprintf(stderr, "however it is recommended to use full command names in scripts.\n");
 204         fprintf(stderr, "All command groups have their manual page named 'btrfs-<group>'.\n");
 205 }
 206
 207 void usage_command_group(const struct cmd_group *grp, int full, int err)
 208 {
 209         const char * const *usagestr = grp->usagestr;
 210         FILE *outf = err ? stderr : stdout;
 211
 212         if (usagestr && *usagestr) {
 213                 fprintf(outf, "usage: %s\n", *usagestr++);
 214                 while (*usagestr)
 215                         fprintf(outf, "   or: %s\n", *usagestr++);
 216         }
 217
 218         fputc('\n', outf);
 219         usage_command_group_internal(grp, full, outf);
 220         fputc('\n', outf);
 221
 222         if (grp->infostr)
 223                 fprintf(outf, "%s\n", grp->infostr);
 224 }
 225
 226 void help_unknown_token(const char *arg, const struct cmd_group *grp)
 227 {
 228         fprintf(stderr, "%s: unknown token '%s'\n", get_argv0_buf(), arg);
 229         usage_command_group(grp, 0, 1);
 230         exit(1);
 231 }
 232
 233 void help_ambiguous_token(const char *arg, const struct cmd_group *grp)
 234 {
 235         const struct cmd_struct *cmd = grp->commands;
 236
 237         fprintf(stderr, "%s: ambiguous token '%s'\n", get_argv0_buf(), arg);
 238         fprintf(stderr, "\nDid you mean one of these ?\n");
 239
 240         for (; cmd->token; cmd++) {
 241                 if (!prefixcmp(cmd->token, arg))
 242                         fprintf(stderr, "\t%s\n", cmd->token);
 243         }
 244
 245         exit(1);
 246 }
 247
 248 void help_command_group(const struct cmd_group *grp, int argc, char **argv)
 249 {
 250         int full = 0;
 251
 252         if (argc > 1) {
 253                 if (!strcmp(argv[1], "--full"))
 254                         full = 1;
 255         }
 256
 257         usage_command_group(grp, full, 0);
 258 }