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