Added ConnectionPool

fixes #7

connection_pool.go

@@ -0,0 +1,47 @@
+package pgx
+
+type ConnectionPool struct {
+	connectionChannel chan *Connection
+	options           map[string]string // options used when establishing connection
+	MaxConnections    int
+}
+
+// options: options used by Connect
+// MaxConnections: max simultaneous connections to use (currently all are immediately connected)
+func NewConnectionPool(options map[string]string, MaxConnections int) (p *ConnectionPool, err error) {
+	p = new(ConnectionPool)
+	p.connectionChannel = make(chan *Connection, MaxConnections)
+	p.MaxConnections = MaxConnections
+
+	p.options = make(map[string]string)
+	for k, v := range options {
+		p.options[k] = v
+	}
+
+	for i := 0; i < p.MaxConnections; i++ {
+		var c *Connection
+		c, err = Connect(options)
+		if err != nil {
+			return
+		}
+		p.connectionChannel <- c
+	}
+
+	return
+}
+
+func (p *ConnectionPool) Acquire() (c *Connection) {
+	c = <-p.connectionChannel
+	return
+}
+
+func (p *ConnectionPool) Release(c *Connection) {
+	p.connectionChannel <- c
+}
+
+func (p *ConnectionPool) Close() {
+	for i := 0; i < p.MaxConnections; i++ {
+		c := <-p.connectionChannel
+		_ = c.Close()
+	}
+}