r9336: 12 May 2004 Kevin Rosenberg (kevin@rosenberg.net)

[clsql.git] / sql / pool.lisp

diff --git a/sql/pool.lisp b/sql/pool.lisp
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+;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
+;;;; *************************************************************************
+;;;; FILE IDENTIFICATION
+;;;;
+;;;; Name:          pool.lisp
+;;;; Purpose:       Support function for connection pool
+;;;; Programmers:   Kevin M. Rosenberg, Marc Battyani
+;;;; Date Started:  Apr 2002
+;;;;
+;;;; $Id$
+;;;;
+;;;; This file, part of CLSQL, is Copyright (c) 2002-2003 by Kevin M. Rosenberg
+;;;;
+;;;; CLSQL users are granted the rights to distribute and use this software
+;;;; as governed by the terms of the Lisp Lesser GNU Public License
+;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
+;;;; *************************************************************************
+
+(in-package #:clsql-sys)
+
+(defvar *db-pool* (make-hash-table :test #'equal))
+(defvar *db-pool-lock* (make-process-lock "DB Pool lock"))
+
+(defclass conn-pool ()
+  ((connection-spec :accessor connection-spec :initarg :connection-spec)
+   (database-type :accessor pool-database-type :initarg :pool-database-type)
+   (free-connections :accessor free-connections
+                    :initform (make-array 5 :fill-pointer 0 :adjustable t))
+   (all-connections :accessor all-connections
+                   :initform (make-array 5 :fill-pointer 0 :adjustable t))
+   (lock :accessor conn-pool-lock
+        :initform (make-process-lock "Connection pool"))))
+
+(defun acquire-from-conn-pool (pool)
+  (or (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
+       (and (plusp (length (free-connections pool)))
+            (vector-pop (free-connections pool))))
+      (let ((conn (connect (connection-spec pool)
+                          :database-type (pool-database-type pool)
+                          :if-exists :new)))
+       (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
+         (vector-push-extend conn (all-connections pool))
+         (setf (conn-pool conn) pool))
+       conn)))
+
+(defun release-to-conn-pool (conn)
+  (let ((pool (conn-pool conn)))
+    (with-process-lock ((conn-pool-lock pool) "Release to pool")
+      (vector-push-extend conn (free-connections pool)))))
+
+(defun clear-conn-pool (pool)
+  (with-process-lock ((conn-pool-lock pool) "Clear pool")
+    (loop for conn across (all-connections pool)
+         do (setf (conn-pool conn) nil)
+         (disconnect :database conn))
+    (setf (fill-pointer (free-connections pool)) 0)
+    (setf (fill-pointer (all-connections pool)) 0))
+  nil)
+
+(defun find-or-create-connection-pool (connection-spec database-type)
+  "Find connection pool in hash table, creates a new connection pool
+if not found"
+  (with-process-lock (*db-pool-lock* "Find-or-create connection")
+    (let* ((key (list connection-spec database-type))
+          (conn-pool (gethash key *db-pool*)))
+      (unless conn-pool
+       (setq conn-pool (make-instance 'conn-pool
+                                      :connection-spec connection-spec
+                                      :pool-database-type database-type))
+       (setf (gethash key *db-pool*) conn-pool))
+      conn-pool)))
+
+(defun acquire-from-pool (connection-spec database-type &optional pool)
+  (unless (typep pool 'conn-pool)
+    (setf pool (find-or-create-connection-pool connection-spec database-type)))
+  (acquire-from-conn-pool pool))
+
+(defun release-to-pool (database)
+  (release-to-conn-pool database))
+
+(defun disconnect-pooled (&optional clear)
+  "Disconnects all connections in the pool."
+  (with-process-lock (*db-pool-lock* "Disconnect pooled")
+    (maphash
+     #'(lambda (key conn-pool)
+        (declare (ignore key))
+        (clear-conn-pool conn-pool))
+     *db-pool*)
+    (when clear (clrhash *db-pool*)))
+  t)
+
+;(defun pool-start-sql-recording (pool &key (types :command))
+;  "Start all stream in the pool recording actions of TYPES"
+;  (dolist (con (pool-connections pool))
+;    (start-sql-recording :type types
+;                       :database (connection-database con))))
+
+;(defun pool-stop-sql-recording (pool &key (types :command))
+;  "Start all stream in the pool recording actions of TYPES"
+;  (dolist (con (pool-connections pool))
+;    (stop-sql-recording :type types
+;                        :database (connection-database con))))
+
+;(defmacro with-database-connection (pool &body body)
+;  `(let ((connection (obtain-connection ,pool))
+;         (results nil))
+;    (unwind-protect
+;         (with-database ((connection-database connection))
+;           (setq results (multiple-value-list (progn ,@body))))
+;      (release-connection connection))
+;    (values-list results)))