From fd7c98f7f6a89ad505b41c7a509a584fa2d389d5 Mon Sep 17 00:00:00 2001
From: Joshua Peek <josh@joshpeek.com>
Date: Thu, 15 Jan 2009 14:01:31 -0600
Subject: [PATCH] Add Locking middleware

---
 lib/rack.rb            |    1 +
 lib/rack/lock.rb       |   16 ++++++++++++++++
 test/spec_rack_lock.rb |   40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 0 deletions(-)
 create mode 100644 lib/rack/lock.rb
 create mode 100644 test/spec_rack_lock.rb

diff --git a/lib/rack.rb b/lib/rack.rb
index f0020c3..c64bfe4 100644
--- a/lib/rack.rb
+++ b/lib/rack.rb
@@ -38,6 +38,7 @@ module Rack
   autoload :Handler, "rack/handler"
   autoload :Head, "rack/head"
   autoload :Lint, "rack/lint"
+  autoload :Lock, "rack/lock"
   autoload :MethodOverride, "rack/methodoverride"
   autoload :Mime, "rack/mime"
   autoload :Recursive, "rack/recursive"
diff --git a/lib/rack/lock.rb b/lib/rack/lock.rb
new file mode 100644
index 0000000..9323852
--- /dev/null
+++ b/lib/rack/lock.rb
@@ -0,0 +1,16 @@
+module Rack
+  class Lock
+    FLAG = 'rack.multithread'.freeze
+
+    def initialize(app, lock = Mutex.new)
+      @app, @lock = app, lock
+    end
+
+    def call(env)
+      old, env[FLAG] = env[FLAG], false
+      @lock.synchronize { @app.call(env) }
+    ensure
+      env[FLAG] = old
+    end
+  end
+end
diff --git a/test/spec_rack_lock.rb b/test/spec_rack_lock.rb
new file mode 100644
index 0000000..3be6fd3
--- /dev/null
+++ b/test/spec_rack_lock.rb
@@ -0,0 +1,40 @@
+require 'test/spec'
+
+require 'rack/mock'
+require 'rack/lock'
+
+context "Rack::Lock" do
+  class Lock
+    attr_reader :synchronized
+
+    def initialize
+      @synchronized = false
+    end
+
+    def synchronize
+      @synchronized = true
+      yield
+    end
+  end
+
+  specify "should call synchronize on lock" do
+    lock = Lock.new
+    env = Rack::MockRequest.env_for("/")
+    app = Rack::Lock.new(lambda { }, lock)
+    lock.synchronized.should.equal false
+    app.call(env)
+    lock.synchronized.should.equal true
+  end
+
+  specify "should set multithread flag to false" do
+    env = Rack::MockRequest.env_for("/")
+    app = Rack::Lock.new(lambda { |env| env['rack.multithread'] })
+    app.call(env).should.equal false
+  end
+
+  specify "should reset original multithread flag when exiting lock" do
+    env = Rack::MockRequest.env_for("/")
+    app = Rack::Lock.new(lambda { |env| env })
+    app.call(env)['rack.multithread'].should.equal true
+  end
+end
-- 
1.6.0.4