Shin-ichiro Hara's ConditionVariable

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_3@481 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 33 insertions, 16 deletions

diff --git a/lib/thread.rb b/lib/thread.rb
index 936768fa9b..baa248e927 100644
--- a/lib/thread.rb
+++ b/lib/thread.rb
@@ -17,6 +17,16 @@ if $DEBUG
   Thread.abort_on_exception = true
 end
 
+def Thread.exclusive
+  begin
+    Thread.critical = true
+    r = yield
+  ensure
+    Thread.critical = false
+  end
+  r
+end
+
 class Mutex
   def initialize
     @waiting = []
@@ -68,39 +78,46 @@ class Mutex
       unlock
     end
   end
+
+  def exclusive_unlock
+    return unless @locked
+    Thread.exclusive do
+      t = @waiting.shift
+      @locked = false
+      t.wakeup if t
+      yield
+    end
+    self
+  end
 end
 
 class ConditionVariable
   def initialize
     @waiters = []
-    @waiters_mutex = Mutex.new
-    @waiters.taint		# enable tainted comunication
-    self.taint
   end
   
   def wait(mutex)
-    mutex.unlock
-    @waiters_mutex.synchronize {
+    mutex.exclusive_unlock do
       @waiters.push(Thread.current)
-    }
-    Thread.stop
+      Thread.stop
+    end
     mutex.lock
   end
   
   def signal
-    @waiters_mutex.synchronize {
-      t = @waiters.shift
-      t.run if t
-    }
+    t = @waiters.shift
+    t.run if t
   end
     
   def broadcast
-    @waiters_mutex.synchronize {
-      for t in @waiters
-	t.run
-      end
+    waitors0 = nil
+    Thread.exclusive do
+      waiters0 = @waitors.dup
       @waiters.clear
-    }
+    end
+    for t in waiters0
+      t.run
+    end
   end
 end