commit bash-20130301 snapshot

examples/functions/coproc.bash

@@ -0,0 +1,108 @@
+# coprocess.bash
+#
+# vi:set sts=2 sw=2 ai:
+#
+
+coprocess_pid=
+
+#
+# coprocess - Start, control, and end coprocesses.
+#
+function coprocess ()
+{
+  while (( $# > 0 )) ; do
+    case "$1" in
+      #
+      # coprocess close
+      #
+      c|cl|clo|clos|close)
+	shift
+	exec 61>&- 62<&-
+	coprocess_pid=
+	if [ "$1" = "-SIGPIPE" ] ; then
+	  # Only print message in an interactive shell
+	  case "$-" in
+	    *i*)
+	      echo 'SIGPIPE' >&2
+	      ;;
+	  esac
+	  return 1
+	fi
+	return 0
+	;;
+
+      #
+      # coprocess open
+      #
+      o|op|ope|open)
+	shift
+	local fifo="/var/tmp/coprocess.$$.$RANDOM"
+
+	local cmd="/bin/bash"
+	if (( $# > 0 )) ; then
+	  cmd="$@"
+	fi
+
+	mkfifo "$fifo.in" || return $?
+	mkfifo "$fifo.out" || {
+	  ret=$?
+	  rm -f "$fifo.in"
+	  return $?
+	}
+
+	( "$@" <$fifo.in >$fifo.out ; rm -f "$fifo.in" "$fifo.out" ) &
+	coprocess_pid=$!
+	exec 61>$fifo.in 62<$fifo.out
+	return 0
+	;;
+
+      #
+      # coprocess print - write to the coprocess
+      #
+      p|pr|pri|prin|print)
+	shift
+	local old_trap=$(trap -p SIGPIPE)
+	trap 'coprocess close -SIGPIPE' SIGPIPE
+	if [ $# -eq 1 ] && [ "$1" = "--stdin" ] ; then
+	  cat >&61
+	else
+	  echo "$@" >&61
+	fi
+	local ret=$?
+	eval "$old_trap"
+	return $ret
+	;;
+
+      #
+      # coprocess read - read from the coprocess
+      #
+      r|re|rea|read)
+	shift
+	local old_trap=$(trap -p SIGPIPE)
+	trap '_coprocess_close -SIGPIPE' SIGPIPE
+	builtin read "$@" <&62
+	local ret=$?
+	eval "$old_trap"
+	return $ret
+	;;
+
+      s|st|sta|stat|statu|status)
+	if [ -z "$coprocess_pid" ] ; then
+	  echo 'no active coprocess'
+	  return 1
+	else
+	  echo "  coprocess is active [$coprocess_pid]"
+	  return 0
+	fi
+	;;
+
+      *)
+	coprocess print "$@"
+	return $?
+	;;
+    esac
+    shift
+  done
+  coprocess status
+  return $?
+}