tool/ifchange

   1 #!/bin/sh
   2 # usage: ifchange target temporary
   3
   4 # Used in generating revision.h via Makefiles.
   5
   6 help() {
   7     cat <<HELP
   8 usage: $0 [options] target new-file
   9 options:
  10   --timestamp[=file] touch timestamp file. (default: prefixed with ".time".
  11                      under the directory of the target)
  12   --keep[=suffix]    keep old file with suffix. (default: '.old')
  13   --empty            assume unchanged if the new file is empty.
  14   --color[=always|auto|never] colorize output.
  15 HELP
  16 }
  17
  18 set -e
  19 timestamp=
  20 keepsuffix=
  21 empty=
  22 color=auto
  23 until [ $# -eq 0 ]; do
  24     case "$1" in
  25         --)
  26             shift
  27             break;
  28             ;;
  29         --timestamp)
  30             timestamp=.
  31             ;;
  32         --timestamp=*)
  33             timestamp=`expr \( "$1" : '[^=]*=\(.*\)' \)`
  34             ;;
  35         --keep)
  36             keepsuffix=.old
  37             ;;
  38         --keep=*)
  39             keepsuffix=`expr \( "$1" : '[^=]*=\(.*\)' \)`
  40             ;;
  41         --empty)
  42             empty=yes
  43             ;;
  44         --color)
  45             color=always
  46             ;;
  47         --color=*)
  48             color=`expr \( "$1" : '[^=]*=\(.*\)' \)`
  49             ;;
  50         --debug)
  51             set -x
  52             ;;
  53         --help)
  54             help
  55             exit
  56             ;;
  57         --*)
  58             echo "$0: unknown option: $1" 1>&2
  59             exit 1
  60             ;;
  61         *)
  62             break
  63             ;;
  64     esac
  65     shift
  66 done
  67
  68 if [ "$#" != 2 ]; then
  69     help
  70     exit 1
  71 fi
  72
  73 target="$1"
  74 temp="$2"
  75 if [ "$temp" = - ]; then
  76     temp="tmpdata$$.tmp~"
  77     cat > "$temp"
  78     trap 'rm -f "$temp"' 0
  79 fi
  80
  81 msg_begin= msg_unchanged= msg_updated= msg_reset=
  82 if [ "$color" = always -o \( "$color" = auto -a -t 1 \) ]; then
  83     msg_begin="\e["
  84     case "`tput smso 2>/dev/null`" in
  85         "$msg_begin"*m)
  86             if [ ${TEST_COLORS:+set} ]; then
  87                 msg_unchanged=`expr ":$TEST_COLORS:" : ".*:pass=\([^:]*\):"` || :
  88                 msg_updated=`expr ":$TEST_COLORS:" : ".*:fail=\([^:]*\):"` || :
  89             fi
  90             msg_unchanged="${msg_begin}${msg_unchanged:-32}m"
  91             msg_updated="${msg_begin}${msg_updated:-31;1}m"
  92             msg_reset="${msg_begin}m"
  93             ;;
  94     esac
  95     unset msg_begin
  96 fi
  97
  98 targetdir=
  99 case "$target" in */*) targetdir=`dirname "$target"`;; esac
 100 if [ -f "$target" -a ! -${empty:+f}${empty:-s} "$temp" ] || cmp "$target" "$temp" >/dev/null 2>&1; then
 101     echo "$target ${msg_unchanged}unchanged${msg_reset}"
 102     rm -f "$temp"
 103 else
 104     echo "$target ${msg_updated}updated${msg_reset}"
 105     [ x"${targetdir}" = x -o -d "${targetdir}" ] || mkdir -p "${targetdir}"
 106     [ x"${keepsuffix}" != x -a -f "$target" ] && mv -f "$target" "${target}${keepsuffix}"
 107     mv -f "$temp" "$target"
 108 fi
 109
 110 if [ -n "${timestamp}" ]; then
 111     if [ x"${timestamp}" = x. ]; then
 112         if [ x"$targetdir" = x ]; then
 113             timestamp=.time."$target"
 114         else
 115             timestamp="$targetdir"/.time.`basename "$target"`
 116         fi
 117     fi
 118     : > "$timestamp"
 119 fi