[FEATURE] oracle provider: initial expression compiler support

Author: jef-n

src/providers/oracle/CMakeLists.txt

@@ -14,6 +14,7 @@ SET(ORACLE_SRCS
   qgsoraclecolumntypethread.cpp
   qgsoraclefeatureiterator.cpp
   qgsoracleconnpool.cpp
+  qgsoracleexpressioncompiler.cpp
 )
 
 SET(ORACLE_MOC_HDRS
@@ -25,6 +26,7 @@ SET(ORACLE_MOC_HDRS
   qgsoracletablemodel.h
   qgsoraclecolumntypethread.h
   qgsoracleconnpool.h
+  qgsoracleexpressioncompiler.h
 )
 
 

src/providers/oracle/qgsoracleexpressioncompiler.cpp

@@ -0,0 +1,73 @@
+/***************************************************************************
+    qgsoracleexpressioncompiler.cpp
+    ----------------------------------------------------
+    date                 : December 2015
+    copyright            : (C) 2015 by Juergen E. Fischer
+    email                : jef at norbit dot de
+ ***************************************************************************
+ *                                                                         *
+ *   This program 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 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsoracleexpressioncompiler.h"
+#include "qgssqlexpressioncompiler.h"
+
+QgsOracleExpressionCompiler::QgsOracleExpressionCompiler( QgsOracleFeatureSource* source )
+    : QgsSqlExpressionCompiler( source->mFields )
+{
+}
+
+QgsSqlExpressionCompiler::Result QgsOracleExpressionCompiler::compileNode( const QgsExpression::Node* node, QString& result )
+{
+  if ( node->nodeType() == QgsExpression::ntBinaryOperator )
+  {
+    const QgsExpression::NodeBinaryOperator *bin( static_cast<const QgsExpression::NodeBinaryOperator*>( node ) );
+
+    switch ( bin->op() )
+    {
+      case QgsExpression::boPow:
+      case QgsExpression::boRegexp:
+      {
+        QString op1, op2;
+
+        if ( compileNode( bin->opLeft(), op1 ) != Complete ||
+             compileNode( bin->opRight(), op2 ) != Complete )
+          return Fail;
+
+        switch ( bin->op() )
+        {
+          case QgsExpression::boPow:
+            result = QString( "power(%1,%2)" ).arg( op1, op2 );
+            return Complete;
+
+          case QgsExpression::boRegexp:
+            result = QString( "regexp_like(%1,%2)" ).arg( op1, op2 );
+            return Complete;
+
+          default:
+            break;
+        }
+      }
+
+      default:
+        break;
+    }
+  }
+
+  //fallback to default handling
+  return QgsSqlExpressionCompiler::compileNode( node, result );
+}
+
+QString QgsOracleExpressionCompiler::quotedIdentifier( const QString& identifier )
+{
+  return QgsOracleConn::quotedIdentifier( identifier );
+}
+
+QString QgsOracleExpressionCompiler::quotedValue( const QVariant& value )
+{
+  return QgsOracleConn::quotedValue( value );
+}

src/providers/oracle/qgsoracleexpressioncompiler.h

@@ -0,0 +1,35 @@
+/***************************************************************************
+    qgsoracleexpressioncompiler.h
+    ----------------------------------------------------
+    date                 : December 2015
+    copyright            : (C) 2015 by Jürgen E. Fischer
+    email                : jef at norbit dot de
+ ***************************************************************************
+ *                                                                         *
+ *   This program 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 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSORACLEEXPRESSIONCOMPILER_H
+#define QGSORACLEEXPRESSIONCOMPILER_H
+
+#include "qgssqlexpressioncompiler.h"
+#include "qgsexpression.h"
+#include "qgsoraclefeatureiterator.h"
+
+class QgsOracleExpressionCompiler : public QgsSqlExpressionCompiler
+{
+  public:
+
+    explicit QgsOracleExpressionCompiler( QgsOracleFeatureSource* source );
+
+  protected:
+    virtual Result compileNode( const QgsExpression::Node* node, QString& result ) override;
+    virtual QString quotedIdentifier( const QString& identifier ) override;
+    virtual QString quotedValue( const QVariant& value ) override;
+};
+
+#endif // QGSORACLEEXPRESSIONCOMPILER_H

src/providers/oracle/qgsoraclefeatureiterator.cpp

@@ -16,16 +16,19 @@
 #include "qgsoraclefeatureiterator.h"
 #include "qgsoracleprovider.h"
 #include "qgsoracleconnpool.h"
+#include "qgsoracleexpressioncompiler.h"
 
 #include "qgslogger.h"
 #include "qgsmessagelog.h"
 #include "qgsgeometry.h"
 
 #include <QObject>
+#include <QSettings>
 
 QgsOracleFeatureIterator::QgsOracleFeatureIterator( QgsOracleFeatureSource* source, bool ownSource, const QgsFeatureRequest &request )
     : QgsAbstractFeatureIteratorFromSource<QgsOracleFeatureSource>( source, ownSource, request )
     , mRewind( false )
+    , mExpressionCompiled( false )
 {
   mConnection = QgsOracleConnPool::instance()->acquireConnection( mSource->mUri.connectionInfo() );
   if ( !mConnection )
@@ -90,6 +93,15 @@ QgsOracleFeatureIterator::QgsOracleFeatureIterator( QgsOracleFeatureSource* sour
       break;
 
     case QgsFeatureRequest::FilterExpression:
+      if ( QSettings().value( "/qgis/compileExpressions", true ).toBool() )
+      {
+        QgsOracleExpressionCompiler compiler( mSource );
+        if ( compiler.compile( request.filterExpression() ) == QgsSqlExpressionCompiler::Complete )
+        {
+          whereClause = QgsOracleUtils::andWhereClauses( whereClause, compiler.result() );
+          mExpressionCompiled = true;
+        }
+      }
       break;
 
     case QgsFeatureRequest::FilterRect:
@@ -128,6 +140,14 @@ QgsOracleFeatureIterator::~QgsOracleFeatureIterator()
   close();
 }
 
+bool QgsOracleFeatureIterator::nextFeatureFilterExpression( QgsFeature& f )
+{
+  if ( !mExpressionCompiled )
+    return QgsAbstractFeatureIterator::nextFeatureFilterExpression( f );
+  else
+    return fetchFeature( f );
+}
+
 bool QgsOracleFeatureIterator::fetchFeature( QgsFeature& feature )
 {
   feature.setValid( false );

src/providers/oracle/qgsoraclefeatureiterator.h

@@ -52,6 +52,7 @@ class QgsOracleFeatureSource : public QgsAbstractFeatureSource
     QSharedPointer<QgsOracleSharedData> mShared;
 
     friend class QgsOracleFeatureIterator;
+    friend class QgsOracleExpressionCompiler;
 };
 
 
@@ -63,20 +64,24 @@ class QgsOracleFeatureIterator : public QgsAbstractFeatureIteratorFromSource<Qgs
     ~QgsOracleFeatureIterator();
 
     //! reset the iterator to the starting position
-    virtual bool rewind();
+    virtual bool rewind() override;
 
     //! end of iterating: free the resources / lock
-    virtual bool close();
+    virtual bool close() override;
 
   protected:
     //! fetch next feature, return true on success
-    virtual bool fetchFeature( QgsFeature& feature );
+    virtual bool fetchFeature( QgsFeature& feature ) override;
+
+    //! fetch next feature filter expression
+    bool nextFeatureFilterExpression( QgsFeature& f ) override;
 
     bool openQuery( QString whereClause );
 
     QgsOracleConn *mConnection;
     QSqlQuery mQry;
     bool mRewind;
+    bool mExpressionCompiled;
     QgsAttributeList mAttributeList;
 };
 

src/providers/postgres/qgspostgresexpressioncompiler.cpp

@@ -1,6 +1,6 @@
 /***************************************************************************
-
-               ----------------------------------------------------
+              qgspostgresexpressioncompiler.cpp
+              ----------------------------------------------------
               date                 : 22.4.2015
               copyright            : (C) 2015 by Matthias Kuhn
               email                : matthias (at) opengis.ch

src/providers/postgres/qgspostgresexpressioncompiler.h

@@ -1,6 +1,6 @@
 /***************************************************************************
-
-               ----------------------------------------------------
+              qgspostgresexpressioncompiler.h
+              ----------------------------------------------------
               date                 : 22.4.2015
               copyright            : (C) 2015 by Matthias Kuhn
               email                : matthias (at) opengis.ch