From 0b728575358645f6e9a3f98959dd6995325f7380 Mon Sep 17 00:00:00 2001
From: Emil Renner Berthing <esmil@mailme.dk>
Date: Wed, 2 Mar 2011 23:18:34 +0100
Subject: initial commit

---
 queued.lua | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 queued.lua

(limited to 'queued.lua')

diff --git a/queued.lua b/queued.lua
new file mode 100644
index 0000000..05496e4
--- /dev/null
+++ b/queued.lua
@@ -0,0 +1,96 @@
+--
+-- This file is part of lem-postgres.
+-- Copyright 2011 Emil Renner Berthing
+--
+-- lem-postgres is free software: you can redistribute it and/or
+-- modify it under the terms of the GNU General Public License as
+-- published by the Free Software Foundation, either version 3 of
+-- the License, or (at your option) any later version.
+--
+-- lem-postgres is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with lem-postgres. If not, see <http://www.gnu.org/licenses/>.
+--
+
+local utils    = require 'lem.utils'
+local postgres = require 'lem.postgres'
+
+local QConnection = {}
+QConnection.__index = QConnection
+
+function QConnection:close()
+	local ok, err = self.conn:close()
+	for i = 1, self.n - 1 do
+		self[i]:wakeup()
+		self[i] = nil
+	end
+	return ok, err
+end
+QConnection.__gc = QConnection.close
+
+do
+	local remove = table.remove
+	local newsleeper = utils.sleeper
+
+	local function lock(self)
+		local n = self.n
+		if n == 0 then
+			self.n = 1
+		else
+			local sleeper = newsleeper()
+			self[n] = sleeper
+			self.n = n + 1
+			sleeper:sleep()
+		end
+		return self.conn
+	end
+	QConnection.lock = lock
+
+	local function unlock(self, ...)
+		local n = self.n - 1
+		self.n = n
+		if n > 0 then
+			remove(self, 1):wakeup()
+		end
+		return ...
+	end
+	QConnection.unlock = unlock
+
+	local function wrap(method)
+		return function(self, ...)
+			return unlock(self, method(lock(self), ...))
+		end
+	end
+
+	local Connection = postgres.Connection
+	QConnection.exec    = wrap(Connection.exec)
+	QConnection.prepare = wrap(Connection.prepare)
+	QConnection.run     = wrap(Connection.run)
+end
+
+local qconnect
+do
+	local setmetatable = setmetatable
+	local connect = postgres.connect
+
+	function qconnect(...)
+		local conn, err = connect(...)
+		if not conn then return nil, err end
+
+		return setmetatable({
+			n = 0,
+			conn = conn,
+		}, QConnection)
+	end
+end
+
+return {
+	QConnection = QConnection,
+	connect = qconnect,
+}
+
+-- vim: syntax=lua ts=2 sw=2 noet:
-- 
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