1 files changed, 65 insertions, 0 deletions
diff --git a/app/app/db/connection_pool.rb b/app/app/db/connection_pool.rb
new file mode 100644
index 0000000..72e47e1
--- /dev/null
+++ b/app/app/db/connection_pool.rb
@@ -0,0 +1,65 @@
+require 'thread'
+
+module HH::Sequel
+  class ConnectionPool
+    attr_reader :max_size, :mutex, :conn_maker
+    attr_reader :available_connections, :allocated, :created_count
+  
+    def initialize(max_size = 4, &block)
+      @max_size = max_size
+      @mutex = Mutex.new
+      @conn_maker = block
+
+      @available_connections = []
+      @allocated = {}
+      @created_count = 0
+    end
+    
+    def size
+      @created_count
+    end
+    
+    def hold
+      t = Thread.current
+      if (conn = owned_connection(t))
+        return yield(conn)
+      end
+      while !(conn = acquire(t))
+        sleep 0.001
+      end
+      begin
+        yield conn
+      ensure
+        release(t)
+      end
+    end
+    
+    def owned_connection(thread)
+      @mutex.synchronize {@allocated[thread]}
+    end
+    
+    def acquire(thread)
+      @mutex.synchronize do
+        @allocated[thread] ||= available
+      end
+    end
+    
+    def available
+      @available_connections.pop || make_new
+    end
+    
+    def make_new
+      if @created_count < @max_size
+        @created_count += 1
+        @conn_maker.call
+      end
+    end
+    
+    def release(thread)
+      @mutex.synchronize do
+        @available_connections << @allocated[thread]
+        @allocated.delete(thread)
+      end
+    end
+  end
+end