1 files changed, 27 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/concurrency/latch.rb b/activesupport/lib/active_support/concurrency/latch.rb
new file mode 100644
index 0000000000..1507de433e
--- /dev/null
+++ b/activesupport/lib/active_support/concurrency/latch.rb
@@ -0,0 +1,27 @@
+require 'thread'
+require 'monitor'
+
+module ActiveSupport
+  module Concurrency
+    class Latch
+      def initialize(count = 1)
+        @count = count
+        @lock = Monitor.new
+        @cv = @lock.new_cond
+      end
+
+      def release
+        @lock.synchronize do
+          @count -= 1 if @count > 0
+          @cv.broadcast if @count.zero?
+        end
+      end
+
+      def await
+        @lock.synchronize do
+          @cv.wait_while { @count > 0 }
+        end
+      end
+    end
+  end
+end