Add connection pool for OGR provider (Funded by Sourcepole QGIS Enter…

…prise)

src/core/qgsconnectionpool.h

@@ -37,6 +37,8 @@
  * - void qgsConnectionPool_ConnectionCreate(QString name, T& c)  ... create a new connection
  * - void qgsConnectionPool_ConnectionDestroy(T c)                ... destroy the connection
  * - QString qgsConnectionPool_ConnectionToName(T c)              ... lookup connection's name (path)
+ * - void qgsConnectionPool_InvalidateConnection(T c)             ... flag a connection as invalid
+ * - bool qgsConnectionPool_ConnectionIsValid(T c)                ... return whether a connection is valid
  *
  * Because of issues with templates and QObject's signals and slots, this class only provides helper functions for QObject-related
  * functionality - the place which uses the template is resonsible for:
@@ -87,6 +89,11 @@ class QgsConnectionPoolGroup
         if ( !conns.isEmpty() )
         {
           Item i = conns.pop();
+          if ( !qgsConnectionPool_ConnectionIsValid( i.c ) )
+          {
+            qgsConnectionPool_ConnectionDestroy( i.c );
+            qgsConnectionPool_ConnectionCreate( connInfo, i.c );
+          }
 
           // no need to run if nothing can expire
           if ( conns.isEmpty() )
@@ -95,6 +102,8 @@ class QgsConnectionPoolGroup
             QMetaObject::invokeMethod( expirationTimer->parent(), "stopExpirationTimer" );
           }
 
+          acquiredConns.append( i.c );
+
           return i.c;
         }
       }
@@ -108,11 +117,14 @@ class QgsConnectionPoolGroup
         return 0;
       }
 
+      acquiredConns.append( c );
       return c;
     }
 
     void release( T conn )
     {
+      acquiredConns.removeAll( conn );
+
       connMutex.lock();
       Item i;
       i.c = conn;
@@ -130,6 +142,18 @@ class QgsConnectionPoolGroup
       sem.release(); // this can unlock a thread waiting in acquire()
     }
 
+    void invalidateConnections()
+    {
+      connMutex.lock();
+      foreach ( Item i, conns )
+      {
+        qgsConnectionPool_InvalidateConnection( i.c );
+      }
+      foreach ( T c, acquiredConns )
+        qgsConnectionPool_InvalidateConnection( c );
+      connMutex.unlock();
+    }
+
   protected:
 
     void initTimer( QObject* parent )
@@ -174,6 +198,7 @@ class QgsConnectionPoolGroup
 
     QString connInfo;
     QStack<Item> conns;
+    QList<T> acquiredConns;
     QMutex connMutex;
     QSemaphore sem;
     QTimer* expirationTimer;
@@ -232,8 +257,6 @@ class QgsConnectionPool
 
   protected:
     T_Groups mGroups;
-
-  private:
     QMutex mMutex;
 };
 

src/providers/ogr/CMakeLists.txt

@@ -1,7 +1,7 @@
 
-SET (OGR_SRCS qgsogrprovider.cpp qgsogrdataitems.cpp qgsogrfeatureiterator.cpp qgsogrgeometrysimplifier.cpp)
+SET (OGR_SRCS qgsogrprovider.cpp qgsogrdataitems.cpp qgsogrfeatureiterator.cpp qgsogrgeometrysimplifier.cpp qgsogrconnpool.cpp)
 
-SET(OGR_MOC_HDRS qgsogrprovider.h qgsogrdataitems.h)
+SET(OGR_MOC_HDRS qgsogrprovider.h qgsogrdataitems.h qgsogrconnpool.h)
 
 ########################################################
 # Build

src/providers/ogr/qgsogrconnpool.cpp

@@ -0,0 +1,41 @@
+/***************************************************************************
+    qgsogrconnpool.cpp
+    ---------------------
+    begin                : May 2015
+    copyright            : (C) 2015 by Sandro Mani
+    email                : smani at sourcepole dot ch
+ ***************************************************************************
+ *                                                                         *
+ *   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 "qgsogrconnpool.h"
+
+
+QgsOgrConnPool* QgsOgrConnPool::instance()
+{
+  static QgsOgrConnPool sInstance;
+  return &sInstance;
+}
+
+QgsOgrConnPool::QgsOgrConnPool() : QgsConnectionPool<QgsOgrConn*, QgsOgrConnPoolGroup>()
+{
+  QgsDebugCall;
+}
+
+QgsOgrConnPool::~QgsOgrConnPool()
+{
+  QgsDebugCall;
+}
+
+void QgsOgrConnPool::invalidateHandles( const QString& connInfo )
+{
+  mMutex.lock();
+  if ( mGroups.contains( connInfo ) )
+    mGroups[connInfo]->invalidateConnections();
+  mMutex.unlock();
+}

src/providers/ogr/qgsogrconnpool.h

@@ -0,0 +1,93 @@
+/***************************************************************************
+    qgsogrconnpool.h
+    ---------------------
+    begin                : May 2015
+    copyright            : (C) 2015 by Sandro Mani
+    email                : smani at sourcepole dot ch
+ ***************************************************************************
+ *                                                                         *
+ *   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 QGSOGRCONNPOOL_H
+#define QGSOGRCONNPOOL_H
+
+#include "qgsconnectionpool.h"
+#include <ogr_api.h>
+
+
+struct QgsOgrConn
+{
+  QString path;
+  OGRDataSourceH ds;
+  bool valid;
+};
+
+inline QString qgsConnectionPool_ConnectionToName( QgsOgrConn* c )
+{
+  return c->path;
+}
+
+inline void qgsConnectionPool_ConnectionCreate( QString connInfo, QgsOgrConn*& c )
+{
+  c = new QgsOgrConn;
+  c->ds = OGROpen( connInfo.toUtf8().constData(), false, NULL );
+  c->path = connInfo;
+  c->valid = true;
+}
+
+inline void qgsConnectionPool_ConnectionDestroy( QgsOgrConn* c )
+{
+  OGR_DS_Destroy( c->ds );
+  delete c;
+}
+
+inline void qgsConnectionPool_InvalidateConnection( QgsOgrConn* c )
+{
+  c->valid = false;
+}
+
+inline bool qgsConnectionPool_ConnectionIsValid( QgsOgrConn* c )
+{
+  return c->valid;
+}
+
+class QgsOgrConnPoolGroup : public QObject, public QgsConnectionPoolGroup<QgsOgrConn*>
+{
+    Q_OBJECT
+
+  public:
+    QgsOgrConnPoolGroup( QString name ) : QgsConnectionPoolGroup<QgsOgrConn*>( name ) { initTimer( this ); }
+
+  protected slots:
+    void handleConnectionExpired() { onConnectionExpired(); }
+    void startExpirationTimer() { expirationTimer->start(); }
+    void stopExpirationTimer() { expirationTimer->stop(); }
+
+  protected:
+    Q_DISABLE_COPY( QgsOgrConnPoolGroup )
+
+};
+
+/** Ogr connection pool - singleton */
+class QgsOgrConnPool : public QgsConnectionPool<QgsOgrConn*, QgsOgrConnPoolGroup>
+{
+  public:
+    static QgsOgrConnPool* instance();
+
+    void invalidateHandles( const QString& connInfo );
+
+  protected:
+    Q_DISABLE_COPY( QgsOgrConnPool )
+
+  private:
+    QgsOgrConnPool();
+    ~QgsOgrConnPool();
+};
+
+
+#endif // QGSOGRCONNPOOL_H

src/providers/ogr/qgsogrfeatureiterator.cpp

@@ -35,27 +35,26 @@
 
 QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrFeatureSource* source, bool ownSource, const QgsFeatureRequest& request )
     : QgsAbstractFeatureIteratorFromSource<QgsOgrFeatureSource>( source, ownSource, request )
-    , ogrDataSource( 0 )
     , ogrLayer( 0 )
     , mSubsetStringSet( false )
     , mGeometrySimplifier( NULL )
 {
   mFeatureFetched = false;
 
-  ogrDataSource = OGROpen( TO8F( mSource->mFilePath ), false, NULL );
+  mConn = QgsOgrConnPool::instance()->acquireConnection( mSource->mFilePath );
 
   if ( mSource->mLayerName.isNull() )
   {
-    ogrLayer = OGR_DS_GetLayer( ogrDataSource, mSource->mLayerIndex );
+    ogrLayer = OGR_DS_GetLayer( mConn->ds, mSource->mLayerIndex );
   }
   else
   {
-    ogrLayer = OGR_DS_GetLayerByName( ogrDataSource, TO8( mSource->mLayerName ) );
+    ogrLayer = OGR_DS_GetLayerByName( mConn->ds, TO8( mSource->mLayerName ) );
   }
 
   if ( !mSource->mSubsetString.isEmpty() )
   {
-    ogrLayer = QgsOgrUtils::setSubsetString( ogrLayer, ogrDataSource, mSource->mEncoding, mSource->mSubsetString );
+    ogrLayer = QgsOgrUtils::setSubsetString( ogrLayer, mConn->ds, mSource->mEncoding, mSource->mSubsetString );
     mSubsetStringSet = true;
   }
 
@@ -215,13 +214,13 @@ bool QgsOgrFeatureIterator::close()
 
   if ( mSubsetStringSet )
   {
-    OGR_DS_ReleaseResultSet( ogrDataSource, ogrLayer );
+    OGR_DS_ReleaseResultSet( mConn->ds, ogrLayer );
   }
 
-  OGR_DS_Destroy( ogrDataSource );
+  QgsOgrConnPool::instance()->releaseConnection( mConn );
+  mConn = 0;
 
   mClosed = true;
-  ogrDataSource = 0;
   return true;
 }
 

src/providers/ogr/qgsogrfeatureiterator.h

@@ -16,6 +16,7 @@
 #define QGSOGRFEATUREITERATOR_H
 
 #include "qgsfeatureiterator.h"
+#include "qgsogrconnpool.h"
 
 #include <ogr_api.h>
 
@@ -71,7 +72,7 @@ class QgsOgrFeatureIterator : public QgsAbstractFeatureIteratorFromSource<QgsOgr
 
     bool mFeatureFetched;
 
-    OGRDataSourceH ogrDataSource;
+    QgsOgrConn* mConn;
     OGRLayerH ogrLayer;
 
     bool mSubsetStringSet;

src/providers/ogr/qgsogrprovider.cpp

@@ -741,6 +741,7 @@ OGRwkbGeometryType QgsOgrProvider::getOgrGeomType( OGRLayerH ogrLayer )
 
 void QgsOgrProvider::loadFields()
 {
+  QgsOgrConnPool::instance()->invalidateHandles( filePath() );
   //the attribute fields need to be read again when the encoding changes
   mAttributeFields.clear();
 
@@ -2522,6 +2523,8 @@ void QgsOgrProvider::recalculateFeatureCount()
   {
     OGR_L_SetSpatialFilter( ogrLayer, filter );
   }
+
+  QgsOgrConnPool::instance()->invalidateHandles( filePath() );
 }
 
 OGRwkbGeometryType QgsOgrProvider::ogrWkbSingleFlatten( OGRwkbGeometryType type )

src/providers/postgres/qgspostgresconnpool.h

@@ -36,6 +36,15 @@ inline void qgsConnectionPool_ConnectionDestroy( QgsPostgresConn* c )
   c->unref(); // will delete itself
 }
 
+inline void qgsConnectionPool_InvalidateConnection( QgsPostgresConn* c )
+{
+}
+
+inline bool qgsConnectionPool_ConnectionIsValid( QgsPostgresConn* c )
+{
+  return true;
+}
+
 
 class QgsPostgresConnPoolGroup : public QObject, public QgsConnectionPoolGroup<QgsPostgresConn*>
 {

src/providers/spatialite/qgsspatialiteconnpool.h

@@ -35,6 +35,15 @@ inline void qgsConnectionPool_ConnectionDestroy( QgsSqliteHandle* c )
   QgsSqliteHandle::closeDb( c );  // will delete itself
 }
 
+inline void qgsConnectionPool_InvalidateConnection( QgsSqliteHandle* c )
+{
+}
+
+inline bool qgsConnectionPool_ConnectionIsValid( QgsSqliteHandle* c )
+{
+  return true;
+}
+
 
 class QgsSpatiaLiteConnPoolGroup : public QObject, public QgsConnectionPoolGroup<QgsSqliteHandle*>
 {