MDL-19057 improved bit operations in oracle, new sql package setup code - all credit goes to Eloy Lafuente; installation instructions and diagnostics to be added later

lib/dml/oci_native_moodle_database.php

@@ -48,6 +48,7 @@ class oci_native_moodle_database extends moodle_database {
     private $unique_session_id; // To store unique_session_id. Needed for temp tables unique naming
 
     private $dblocks_supported = null; // To cache locks support along the connection life
+    private $bitwise_supported = null; // To cache bitwise operations support along the connection life
 
 
     /**
@@ -1126,7 +1127,7 @@ class oci_native_moodle_database extends moodle_database {
         $stmt = $this->parse_query($sql);
         $descriptors = $this->bind_params($stmt, $params, $table);
         if ($returning) {
-            oci_bind_by_name($stmt, ":oracle_id", $id, -1, SQLT_INT);
+            oci_bind_by_name($stmt, ":oracle_id", $id, 10, SQLT_INT);
         }
         $result = oci_execute($stmt, $this->commit_status);
         $this->free_descriptors($descriptors);
@@ -1366,6 +1367,27 @@ class oci_native_moodle_database extends moodle_database {
         return ' FROM dual';
     }
 
+// Bitwise operations
+   protected function bitwise_supported() {
+        if (isset($this->bitwise_supported)) { // Use cached value if available
+            return $this->bitwise_supported;
+        }
+        $sql = "SELECT 1
+                FROM user_objects
+                WHERE object_type = 'PACKAGE BODY'
+                  AND object_name = 'MOODLE_BITS'
+                  AND status = 'VALID'";
+        $this->query_start($sql, null, SQL_QUERY_AUX);
+        $stmt = $this->parse_query($sql);
+        $result = oci_execute($stmt, $this->commit_status);
+        $this->query_end($result, $stmt);
+        $records = null;
+        oci_fetch_all($stmt, $records, 0, -1, OCI_FETCHSTATEMENT_BY_ROW);
+        oci_free_statement($stmt);
+        $this->bitwise_supported = isset($records[0]) && reset($records[0]) ? true : false;
+        return $this->bitwise_supported;
+    }
+
     public function sql_bitand($int1, $int2) {
         return 'bitand((' . $int1 . '), (' . $int2 . '))';
     }
@@ -1375,10 +1397,20 @@ class oci_native_moodle_database extends moodle_database {
     }
 
     public function sql_bitor($int1, $int2) {
+        // Use the MOODLE_BITS package if available
+        if ($this->bitwise_supported()) {
+            return 'MOODLE_BITS.BITOR(' . $int1 . ', ' . $int2 . ')';
+        }
+        // fallback to PHP bool operations, can break if using placeholders
         return '((' . $int1 . ') + (' . $int2 . ') - ' . $this->sql_bitand($int1, $int2) . ')';
     }
 
     public function sql_bitxor($int1, $int2) {
+        // Use the MOODLE_BITS package if available
+        if ($this->bitwise_supported()) {
+            return 'MOODLE_BITS.BITXOR(' . $int1 . ', ' . $int2 . ')';
+        }
+        // fallback to PHP bool operations, can break if using placeholders
         return '(' . $this->sql_bitor($int1, $int2) . ' - ' . $this->sql_bitand($int1, $int2) . ')';
     }
 

lib/dml/oci_native_moodle_package.sql

@@ -0,0 +1,112 @@
+-- This file is part of Moodle - http://moodle.org/
+--
+-- Moodle 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.
+--
+-- Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * @package    core
+ * @subpackage dml
+ * @copyright  2009 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @version    20091010 (plz, keep this updated for easier reference)
+ */
+
+/**
+ * This sql script generates various PL/SQL packages needed to provide
+ * cross-db compatibility in the Moodle 2.x DB API with some operations
+ * not natively supported by Oracle, namely:
+ *  - MOODLE_LOCKS: Application locks used by Moodle DB sessions. It uses
+ *                  the DBMS_LOCK package so execution must be granted
+ *                  to the Moodle DB user by SYS to work properly.
+ *  - MOODLE_BITS: To provide cross-db bitwise operations to be used by the
+ *                 sql_bitXXX() helper functions
+ */
+
+CREATE OR REPLACE PACKAGE MOODLE_BITS AS
+
+FUNCTION BITOR (value1 IN INTEGER, value2 IN INTEGER) RETURN INTEGER;
+FUNCTION BITXOR(value1 IN INTEGER, value2 IN INTEGER) RETURN INTEGER;
+
+END MOODLE_BITS;
+/
+
+CREATE OR REPLACE PACKAGE BODY MOODLE_BITS AS
+
+FUNCTION BITOR(value1 IN INTEGER, value2 IN INTEGER) RETURN INTEGER IS
+
+BEGIN
+    RETURN value1 + value2 - BITAND(value1,value2);
+END BITOR;
+
+FUNCTION BITXOR(value1 IN INTEGER, value2 IN INTEGER) RETURN INTEGER IS
+
+BEGIN
+    RETURN MOODLE_BITS.BITOR(value1,value2) - BITAND(value1,value2);
+END BITXOR;
+
+END MOODLE_BITS;
+/
+
+CREATE OR REPLACE PACKAGE MOODLE_LOCKS AS
+
+FUNCTION GET_HANDLE  (lock_name IN VARCHAR2) RETURN VARCHAR2;
+FUNCTION GET_LOCK    (lock_name IN VARCHAR2, lock_timeout IN INTEGER) RETURN INTEGER;
+FUNCTION RELEASE_LOCK(lock_name IN VARCHAR2) RETURN INTEGER;
+
+END MOODLE_LOCKS;
+/
+
+CREATE OR REPLACE PACKAGE BODY MOODLE_LOCKS AS
+
+FUNCTION GET_HANDLE(lock_name IN VARCHAR2) RETURN VARCHAR2 IS
+    PRAGMA AUTONOMOUS_TRANSACTION;
+    lock_handle VARCHAR2(128);
+
+BEGIN
+    DBMS_LOCK.ALLOCATE_UNIQUE (
+        lockname => lock_name,
+        lockhandle => lock_handle,
+        expiration_secs => 864000);
+    RETURN lock_handle;
+END GET_HANDLE;
+
+FUNCTION GET_LOCK(lock_name IN VARCHAR2, lock_timeout IN INTEGER) RETURN INTEGER IS
+    lock_status NUMBER;
+BEGIN
+    lock_status := DBMS_LOCK.REQUEST(
+                       lockhandle => GET_HANDLE(lock_name),
+                       lockmode => DBMS_LOCK.X_MODE, -- eXclusive
+                       timeout => lock_timeout,
+                       release_on_commit => FALSE);
+    CASE lock_status
+        WHEN 0 THEN NULL;
+        WHEN 2 THEN RAISE_APPLICATION_ERROR(-20000,'deadlock detected');
+        WHEN 4 THEN RAISE_APPLICATION_ERROR(-20000,'lock already obtained');
+        ELSE RAISE_APPLICATION_ERROR(-20000,'request lock failed - ' || lock_status);
+    END CASE;
+    RETURN 1;
+END GET_LOCK;
+
+FUNCTION RELEASE_LOCK(lock_name IN VARCHAR2) RETURN INTEGER IS
+    lock_status NUMBER;
+BEGIN
+    lock_status := DBMS_LOCK.RELEASE(
+                      lockhandle => GET_HANDLE(lock_name));
+    IF lock_status > 0 THEN
+        RAISE_APPLICATION_ERROR(-20000,'release lock failed - ' || lock_status);
+    END IF;
+    RETURN 1;
+END RELEASE_LOCK;
+
+END MOODLE_LOCKS;
+/