funcs/gsu

   1 # gsu -- the global subcommand utility
   2 # (C) 2006-2007 Andre Noll
   3
   4 gsu_init_errors()
   5 {
   6         gsu_errors="
   7 GSU_SUCCESS                     success
   8 E_GSU_BAD_COMMAND               invalid command
   9 E_GSU_NOT_A_NUMBER              not a number
  10 $gsu_errors
  11 "
  12         local a b i
  13         local i=0
  14         while read a b; do
  15                 if test -z "$a"; then
  16                         continue
  17                 fi
  18                 #echo "a:$a,  b: $b"
  19                 gsu_error_txt[i]="$b"
  20                 eval $a=$i
  21                 i=$((i + 1))
  22         done << EOF
  23         $gsu_errors
  24 EOF
  25 }
  26 export -f gsu_init_errors
  27
  28 # check if $1 is a number
  29 gsu_is_a_number()
  30 {
  31         result="$1"
  32         if test "$1" -eq "$1" &> /dev/null; then
  33                 ret=$GSU_SUCCESS
  34         else
  35                 ret=-$E_GSU_NOT_A_NUMBER
  36         fi
  37 }
  38 export -f gsu_is_a_number
  39
  40 gsu_short_msg()
  41 {
  42         echo "$1" 1>&2
  43 }
  44 export -f gsu_short_msg
  45
  46 gsu_msg()
  47 {
  48         gsu_short_msg "$gsu_self: $1"
  49 }
  50 export -f gsu_msg
  51
  52 gsu_date_msg()
  53 {
  54         gsu_short_msg "$gsu_self $(date): $1"
  55 }
  56 export -f gsu_date_msg
  57
  58 gsu_banner_msg()
  59 {
  60         local txt="*** $gsu_self --"
  61         if test -z "$gsu_banner_txt"; then
  62                 txt="$txt set \$gsu_banner_txt to customize this message"
  63         else
  64                 txt="$txt $gsu_banner_txt"
  65         fi
  66         gsu_short_msg "$txt ***"
  67 }
  68 export -f gsu_banner_msg
  69
  70 gsu_err_msg()
  71 {
  72         local txt="$result" err
  73
  74         gsu_is_a_number "$ret"
  75         if test $ret -lt 0; then
  76                 gsu_msg "unknown error ($ret:$txt)"
  77                 exit 1
  78         fi
  79         if test $result -ge 0; then
  80                 gsu_msg "unknown error ($result:$txt)"
  81                 exit 1
  82         fi
  83         err=$((0 - $result))
  84         if test -n "$txt"; then
  85                 txt="$txt: ${gsu_error_txt[$err]}"
  86         else
  87                 txt="${gsu_error_txt[$err]}"
  88         fi
  89         echo "$gsu_self: $txt" 1>&2
  90 }
  91 export -f gsu_err_msg
  92
  93 gsu_usage()
  94 {
  95         gsu_short_msg "Usage: $gsu_self command [options]"
  96 }
  97 export -f gsu_usage
  98
  99 export gsu_help_txt="
 100 Print online help.
 101
 102 Usage: help [command]
 103
 104 Without arguments, print the list of available commands. Otherwise,
 105 print the help text for the given command."
 106 com_help()
 107 {
 108         local a b
 109         if test -z "$1"; then
 110                 gsu_banner_msg
 111                 gsu_usage
 112                 # sed is magic, baby
 113                 grep -A 2 "^com_\([a-zA-Z_0-9]\+\)()" $0 \
 114                         | grep -v -- '--' \
 115                         | sed -e '/^com_\([a-zA-Z_0-9]\+\)()/bs' \
 116                                 -e 'H;$!d;x;s/\n//g;b' \
 117                                 -e :s \
 118                                 -e 'x;s/\n//g;${p;x;}' \
 119                         | sed -e 's/^com_\([a-zA-Z_0-9]\+\)()#*/\1\t/' \
 120                         | sort \
 121                         | while read a b; do
 122                                 echo -en "$a\t"
 123                                 if test ${#a} -lt 8; then
 124                                         echo -en "\t"
 125                                 fi
 126                                 echo "$b"
 127                         done
 128                 echo
 129                 gsu_msg "Try $gsu_self help <command> for info on <command>."
 130                 ret=$GSU_SUCCESS
 131                 return
 132         fi
 133         if test "$1" = "help"; then
 134                 gsu_short_msg "$gsu_help_txt"
 135                 ret=$GSU_SUCCESS
 136                 return
 137         fi
 138         ret=$GSU_SUCCESS
 139         if grep -q "^com_$1()" $0; then
 140                 sed -e "1,/com_$1()/d" -e '/^{/,$d' -e 's/^## *//' $0
 141                 return
 142         fi
 143         gsu_print_available_commands
 144         result="$1"
 145         ret=-$E_GSU_BAD_COMMAND
 146 }
 147 export -f com_help
 148
 149 gsu_available_commands()
 150 {
 151         result="$( (echo help; grep "^com_[a-z_]\+()" $0) \
 152                 | sed -e 's/^com_//' -e 's/()//' \
 153                 | sort \
 154                 | tr '\n' ' ')"
 155         ret=$SUCCESS
 156 }
 157 export -f gsu_available_commands
 158
 159 gsu_print_available_commands()
 160 {(
 161         local i count
 162         gsu_short_msg "Available commands:"
 163         for i in $gsu_cmds; do
 164                 printf "$i"
 165                 count=$((count + 1))
 166                 if test $((count % 4)) -eq 0; then
 167                         echo
 168                 else
 169                         printf "\t"
 170                         if test ${#i} -lt 8; then
 171                                 printf "\t"
 172                         fi
 173                 fi
 174         done
 175         echo
 176 ) 2>&1
 177 }
 178 export -f gsu_print_available_commands
 179
 180 gsu()
 181 {
 182         gsu_self="$(basename $0)"
 183         gsu_init_errors
 184         gsu_available_commands
 185         gsu_cmds="$result"
 186         if test $# -eq 0; then
 187                 gsu_usage
 188                 gsu_print_available_commands
 189                 exit 1
 190         fi
 191         arg="$1"
 192         shift
 193         for i in $gsu_cmds; do
 194                 if test "$arg" = "$i"; then
 195                         com_$arg $*
 196                         if test $ret -lt 0; then
 197                                 gsu_err_msg
 198                                 exit 1
 199                         fi
 200                         exit 0
 201                 fi
 202         done
 203         ret=-$E_GSU_BAD_COMMAND
 204         result="$arg"
 205         gsu_err_msg
 206         gsu_print_available_commands
 207         exit 1
 208 }
 209 # no need to export this