Use Monitor in sync delegator, so methods can be reentrant.

Author: headius

lib/thread_safe/synchronized_delegator.rb

@@ -1,13 +1,14 @@
 require 'delegate'
+require 'monitor'
 
 # This class provides a trivial way to synchronize all calls to a given object
-# by wrapping it with a `Delegator` that performs `Mutex#lock/unlock` calls
+# by wrapping it with a `Delegator` that performs `Monitor#enter/exit` calls
 # around the delegated `#send`. Example:
 #
 #   array = [] # not thread-safe on many impls
 #   array = SynchronizedDelegator.new([]) # thread-safe
 #
-# A simple `Mutex` provides a very coarse-grained way to synchronize a given
+# A simple `Monitor` provides a very coarse-grained way to synchronize a given
 # object, in that it will cause synchronization for methods that have no
 # need for it, but this is a trivial way to get thread-safety where none may
 # exist currently on some implementations.
@@ -18,33 +19,33 @@ class SynchronizedDelegator < SimpleDelegator
 
   def initialize(obj)
     __setobj__(obj)
-    @mutex = Mutex.new
+    @monitor = Monitor.new
   end
 
   def method_missing(method, *args, &block)
-    mutex = @mutex
+    monitor = @monitor
     begin
-      mutex.lock
+      monitor.enter
       super
     ensure
-      mutex.unlock
+      monitor.exit
     end
   end
 
   # Work-around for 1.8 std-lib not passing block around to delegate.
   # @private
   def method_missing(method, *args, &block)
-    mutex = @mutex
+    monitor = @monitor
     begin
-      mutex.lock
+      monitor.enter
       target = self.__getobj__
       if target.respond_to?(method)
         target.__send__(method, *args, &block)
       else
         super(method, *args, &block)
       end
     ensure
-      mutex.unlock
+      monitor.exit
     end
   end if RUBY_VERSION[0, 3] == '1.8'