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", (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         fputc('\n', outf);
  47
  48         if (flags & USAGE_LISTING)
  49                 pad = 8;
  50         else
  51                 fputc('\n', outf);
  52
  53         fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
  54
  55         /* a long (possibly multi-line) description (optional) */
  56         if (!*usagestr || ((flags & USAGE_LONG) == 0))
  57                 return 0;
  58
  59         if (**usagestr)
  60                 fputc('\n', outf);
  61         while (*usagestr && **usagestr)
  62                 fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
  63
  64         /* options (optional) */
  65         if (!*usagestr || ((flags & USAGE_OPTIONS) == 0))
  66                 return 0;
  67
  68         /*
  69          * options (if present) should always (even if there is no long
  70          * description) be prepended with an empty line, skip it
  71          */
  72         usagestr++;
  73
  74         fputc('\n', outf);
  75         while (*usagestr)
  76                 fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
  77
  78         return 0;
  79 }
  80
  81 static int usage_command_internal(const char * const *usagestr,
  82                                   const char *token, int full, int lst,
  83                                   int alias, FILE *outf)
  84 {
  85         unsigned int flags = 0;
  86         int ret;
  87
  88         if (!alias)
  89                 flags |= USAGE_SHORT;
  90         if (full)
  91                 flags |= USAGE_LONG | USAGE_OPTIONS;
  92         if (lst)
  93                 flags |= USAGE_LISTING;
  94
  95         ret = do_usage_one_command(usagestr, flags, outf);
  96         switch (ret) {
  97         case -1:
  98                 fprintf(outf, "No usage for '%s'\n", token);
  99                 break;
 100         case -2:
 101                 fprintf(outf, "No short description for '%s'\n", token);
 102                 break;
 103         }
 104
 105         return ret;
 106 }
 107
 108 static void usage_command_usagestr(const char * const *usagestr,
 109                                    const char *token, int full, int err)
 110 {
 111         FILE *outf = err ? stderr : stdout;
 112         int ret;
 113
 114         ret = usage_command_internal(usagestr, token, full, 0, 0, outf);
 115         if (!ret)
 116                 fputc('\n', outf);
 117 }
 118
 119 void usage_command(const struct cmd_struct *cmd, int full, int err)
 120 {
 121         usage_command_usagestr(cmd->usagestr, cmd->token, full, err);
 122 }
 123
 124 void usage(const char * const *usagestr)
 125 {
 126         usage_command_usagestr(usagestr, NULL, 1, 1);
 127         exit(1);
 128 }
 129
 130 static void usage_command_group_internal(const struct cmd_group *grp, int full,
 131                                          FILE *outf)
 132 {
 133         const struct cmd_struct *cmd = grp->commands;
 134         int do_sep = 0;
 135
 136         for (; cmd->token; cmd++) {
 137                 if (cmd->flags & CMD_HIDDEN)
 138                         continue;
 139
 140                 if (full && cmd != grp->commands)
 141                         fputc('\n', outf);
 142
 143                 if (!cmd->next) {
 144                         if (do_sep) {
 145                                 fputc('\n', outf);
 146                                 do_sep = 0;
 147                         }
 148
 149                         usage_command_internal(cmd->usagestr, cmd->token, full,
 150                                                1, cmd->flags & CMD_ALIAS, outf);
 151                         continue;
 152                 }
 153
 154                 /* this is an entry point to a nested command group */
 155
 156                 if (!full && cmd != grp->commands)
 157                         fputc('\n', outf);
 158
 159                 usage_command_group_internal(cmd->next, full, outf);
 160
 161                 if (!full)
 162                         do_sep = 1;
 163         }
 164 }
 165
 166 void usage_command_group_short(const struct cmd_group *grp)
 167 {
 168         const char * const *usagestr = grp->usagestr;
 169         FILE *outf = stdout;
 170         const struct cmd_struct *cmd;
 171
 172         if (usagestr && *usagestr) {
 173                 fprintf(outf, "usage: %s\n", *usagestr++);
 174                 while (*usagestr)
 175                         fprintf(outf, "   or: %s\n", *usagestr++);
 176         }
 177
 178         fputc('\n', outf);
 179
 180         fprintf(outf, "Command groups:\n");
 181         for (cmd = grp->commands; cmd->token; cmd++) {
 182                 if (cmd->flags & CMD_HIDDEN)
 183                         continue;
 184
 185                 if (!cmd->next)
 186                         continue;
 187
 188                 fprintf(outf, "  %-16s  %s\n", cmd->token, cmd->next->infostr);
 189         }
 190
 191         fprintf(outf, "\nCommands:\n");
 192         for (cmd = grp->commands; cmd->token; cmd++) {
 193                 if (cmd->flags & CMD_HIDDEN)
 194                         continue;
 195
 196                 if (cmd->next)
 197                         continue;
 198
 199                 fprintf(outf, "  %-16s  %s\n", cmd->token, cmd->usagestr[1]);
 200         }
 201
 202         fputc('\n', outf);
 203         fprintf(stderr, "For an overview of a given command use 'btrfs command --help'\n");
 204         fprintf(stderr, "or 'btrfs [command...] --help --full' to print all available options.\n");
 205         fprintf(stderr, "Any command name can be shortened as far as it stays unambiguous,\n");
 206         fprintf(stderr, "however it is recommended to use full command names in scripts.\n");
 207         fprintf(stderr, "All command groups have their manual page named 'btrfs-<group>'.\n");
 208 }
 209
 210 void usage_command_group(const struct cmd_group *grp, int full, int err)
 211 {
 212         const char * const *usagestr = grp->usagestr;
 213         FILE *outf = err ? stderr : stdout;
 214
 215         if (usagestr && *usagestr) {
 216                 fprintf(outf, "usage: %s\n", *usagestr++);
 217                 while (*usagestr)
 218                         fprintf(outf, "   or: %s\n", *usagestr++);
 219         }
 220
 221         fputc('\n', outf);
 222         usage_command_group_internal(grp, full, outf);
 223         fputc('\n', outf);
 224
 225         if (grp->infostr)
 226                 fprintf(outf, "%s\n", grp->infostr);
 227 }
 228
 229 void help_unknown_token(const char *arg, const struct cmd_group *grp)
 230 {
 231         fprintf(stderr, "%s: unknown token '%s'\n", get_argv0_buf(), arg);
 232         usage_command_group(grp, 0, 1);
 233         exit(1);
 234 }
 235
 236 void help_ambiguous_token(const char *arg, const struct cmd_group *grp)
 237 {
 238         const struct cmd_struct *cmd = grp->commands;
 239
 240         fprintf(stderr, "%s: ambiguous token '%s'\n", get_argv0_buf(), arg);
 241         fprintf(stderr, "\nDid you mean one of these ?\n");
 242
 243         for (; cmd->token; cmd++) {
 244                 if (!prefixcmp(cmd->token, arg))
 245                         fprintf(stderr, "\t%s\n", cmd->token);
 246         }
 247
 248         exit(1);
 249 }
 250
 251 void help_command_group(const struct cmd_group *grp, int argc, char **argv)
 252 {
 253         int full = 0;
 254
 255         if (argc > 1) {
 256                 if (!strcmp(argv[1], "--full"))
 257                         full = 1;
 258         }
 259
 260         usage_command_group(grp, full, 0);
 261 }
 262
 263 int prefixcmp(const char *str, const char *prefix)
 264 {
 265         for (; ; str++, prefix++)
 266                 if (!*prefix)
 267                         return 0;
 268                 else if (*str != *prefix)
 269                         return (unsigned char)*prefix - (unsigned char)*str;
 270 }
 271