Sorry, reverted. Mutex is damn slow.....

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@9774 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,8 +1,3 @@
-Fri Dec 30 18:27:00 2005  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
-
-	* lib/generator.rb: uses Mutex instead of Thread.critical.
-	  [ruby-dev:28184]
-
 Fri Dec 30 18:22:42 2005  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* gc.c (garbage_collect): mark objects refered from aborting threads.

lib/generator.rb

@@ -23,7 +23,6 @@
 #
 # See the respective classes for examples of usage.
 
-require "thread"
 
 #
 # Generator converts an internal iterator (i.e. an Enumerable object)
@@ -72,24 +71,17 @@ class Generator
     end
     @index = 0
     @queue = []
-    @mutex = Mutex.new
-    @main_cond = ConditionVariable.new
-    @loop_cond = ConditionVariable.new
-    entered = false
     @loop_thread = Thread.new do
-      @mutex.synchronize do
-        entered = true
-        @loop_cond.wait(@mutex)
+      Thread.stop
       begin
         @block.call(self)
       rescue
-          @main_thread.raise $!
+        @main_thread.raise
       ensure
-          @main_cond.signal
+        @main_thread.wakeup
       end
     end
-    end
-    Thread.pass until entered && !@mutex.locked?
+    Thread.pass until @loop_thread.stop?
     self
   end
 
@@ -98,26 +90,33 @@ class Generator
     if Thread.current != @loop_thread
       raise "should be called in Generator.new{|g| ... }"
     end
+    Thread.critical = true
+    begin
       @queue << value
-    @main_cond.signal
-    @loop_cond.wait(@mutex)
+      @main_thread.wakeup
+      Thread.stop
+    ensure
+      Thread.critical = false
+    end
     self
   end
 
   # Returns true if the generator has reached the end.
   def end?
-    @mutex.synchronize do
-      if @queue.empty? && @loop_thread.alive?
+    if @queue.empty?
       if @main_thread
         raise "should not be called in Generator.new{|g| ... }"
       end
+      Thread.critical = true
       begin
         @main_thread = Thread.current
-          @loop_cond.signal
-          @main_cond.wait(@mutex)
+        @loop_thread.wakeup
+        Thread.stop
+      rescue ThreadError
+        # ignore
       ensure
         @main_thread = nil
-        end
+        Thread.critical = false
       end
     end
     @queue.empty?