From 25d854c67c3ef31d9d9fbbb0549f73d470857825 Mon Sep 17 00:00:00 2001
From: skodak <skodak>
Date: Sun, 25 May 2008 19:56:34 +0000
Subject: [PATCH] MDL-14910 added option to dispose existing database instance
 (closes connection and releases all resources)

---
 lib/ddl/database_manager.php      | 11 +++++++++++
 lib/ddl/sql_generator.php         |  7 +++++++
 lib/dml/adodb_moodle_database.php | 20 +++++++++++++-------
 lib/dml/moodle_database.php       | 13 +++++++++++++
 4 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/lib/ddl/database_manager.php b/lib/ddl/database_manager.php
index 67451235e7..1b2d140be7 100644
--- a/lib/ddl/database_manager.php
+++ b/lib/ddl/database_manager.php
@@ -46,6 +46,17 @@ class database_manager {
         $this->generator = $generator;
     }
 
+    /**
+     * Release all resources
+     */
+    public function dispose() {
+        if ($this->generator) {
+            $this->generator->dispose();
+            $this->generator = null;
+        }
+        $this->mdb       = null;
+    }
+
     /**
      * This function will execute an array of SQL commands, returning
      * true/false if any error is found and stopping/continue as desired.
diff --git a/lib/ddl/sql_generator.php b/lib/ddl/sql_generator.php
index 67b2ef29f3..c2b37404a9 100644
--- a/lib/ddl/sql_generator.php
+++ b/lib/ddl/sql_generator.php
@@ -135,6 +135,13 @@ abstract class sql_generator {
         $this->mdb            = $mdb; // this creates circular reference - the other link must be unset when closing db
     }
 
+    /**
+     * Release all resources
+     */
+    public function dispose() {
+        $this->mdb = null;
+    }
+
     /**
      * Given one string (or one array), ends it with statement_end
      */
diff --git a/lib/dml/adodb_moodle_database.php b/lib/dml/adodb_moodle_database.php
index ff2b5532c3..49359ced51 100644
--- a/lib/dml/adodb_moodle_database.php
+++ b/lib/dml/adodb_moodle_database.php
@@ -39,13 +39,10 @@ abstract class adodb_moodle_database extends moodle_database {
         return $cfg;
     }
 
-    //TODO: preconfigure_dbconnection(): Decide if this should be declared as abstract because all adodb drivers will need it
     /**
      * Adodb preconnection routines, ususally sets up needed defines;
      */
-    protected function preconfigure_dbconnection() {
-        // empty
-    }
+    protected abstract function preconfigure_dbconnection();
 
     public function connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null) {
         $this->dbhost    = $dbhost;
@@ -83,12 +80,21 @@ abstract class adodb_moodle_database extends moodle_database {
         return true;
     }
 
-    //TODO: configure_dbconnection(): Decide if this should be declared as abstract because all adodb drivers will need it
     /**
      * Adodb post connection routines, usually sets up encoding,e tc.
      */
-    protected function configure_dbconnection() {
-        // empty
+    protected abstract function configure_dbconnection();
+
+    /**
+     * Close database connection and release all resources
+     * and memory (especially circular memory references).
+     * Do NOT use connect() again, create a new instance if needed.
+     */
+    public function dispose() {
+        if ($this->db) {
+            $this->db->Close();
+        }
+        parent::dispose();
     }
 
     //TODO: make all dblibraries return this info in a structured way (new server_info class or so, like database_column_info class)
diff --git a/lib/dml/moodle_database.php b/lib/dml/moodle_database.php
index cbcd8d877f..9df73d679c 100644
--- a/lib/dml/moodle_database.php
+++ b/lib/dml/moodle_database.php
@@ -106,6 +106,19 @@ abstract class moodle_database {
      */
     public abstract function connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null);
 
+    /**
+     * Close database connection and release all resources
+     * and memory (especially circular memory references).
+     * Do NOT use connect() again, create a new instance if needed.
+     */
+    public function dispose() {
+        if ($this->database_manager) {
+            $this->database_manager->dispose();
+            $this->database_manager = null;
+        }
+        $this->columns   = array();
+    }
+
     /**
      * Returns database server info array
      * @return array
-- 
2.39.5