Add indexable vector layer cache

src/core/CMakeLists.txt

@@ -49,6 +49,9 @@ SET(QGIS_CORE_SRCS
   qgis.cpp
   qgsapplication.cpp
   qgsattributeaction.cpp
+  qgscachedfeatureiterator.cpp
+  qgscacheindex.cpp
+  qgscacheindexfeatureid.cpp
   qgsbrowsermodel.cpp
   qgscentralpointpositionmanager.cpp
   qgsclipper.cpp
@@ -68,6 +71,7 @@ SET(QGIS_CORE_SRCS
   qgsfeaturestore.cpp
   qgsfield.cpp
   qgsgeometry.cpp
+  qgsgeometrycache.cpp
   qgsgeometryvalidator.cpp
   qgsgml.cpp
   qgsgmlschema.cpp
@@ -113,6 +117,7 @@ SET(QGIS_CORE_SRCS
   qgscoordinatereferencesystem.cpp
   qgstolerance.cpp
   qgsvectordataprovider.cpp
+  qgsvectorlayercache.cpp
   qgsvectorfilewriter.cpp
   qgsvectorlayer.cpp
   qgsvectorlayercache.cpp
@@ -318,6 +323,7 @@ SET(QGIS_CORE_MOC_HDRS
   qgsvectorlayereditbuffer.h
   qgsnetworkaccessmanager.h
   qgsvectordataprovider.h
+  qgsvectorlayercache.h
   qgsgeometryvalidator.h
 
   composer/qgsaddremoveitemcommand.h
@@ -375,6 +381,9 @@ SET(QGIS_CORE_HDRS
   qgis.h
   qgsapplication.h
   qgsattributeaction.h
+  qgscachedfeatureiterator.h
+  qgscacheindex.h
+  qgscacheindexfeatureid.h
   qgscentralpointpositionmanager.h
   qgsclipper.h
   qgscontexthelp.h
@@ -394,6 +403,7 @@ SET(QGIS_CORE_HDRS
   qgsgeometry.h
   qgsgml.h
   qgsgmlschema.h
+  qgsgeometrycache.h
   qgshttptransaction.h
   qgslabel.h
   qgslabelattributes.h
@@ -432,6 +442,7 @@ SET(QGIS_CORE_HDRS
   qgssnapper.h
   qgscoordinatereferencesystem.h
   qgsvectordataprovider.h
+  qgsvectorlayercache.h
   qgsvectorfilewriter.h
   qgsvectorlayer.h
   qgsvectorlayercache.h

src/core/qgscachedfeatureiterator.cpp

@@ -0,0 +1,89 @@
+/***************************************************************************
+    qgscachedfeatureiterator.cpp
+     --------------------------------------
+    Date                 : 12.2.2013
+    Copyright            : (C) 2013 Matthias Kuhn
+    Email                : matthias dot kuhn at gmx 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 "qgscachedfeatureiterator.h"
+#include "qgsvectorlayercache.h"
+#include "qgsvectordataprovider.h"
+
+QgsCachedFeatureIterator::QgsCachedFeatureIterator( QgsVectorLayerCache *vlCache, QgsFeatureRequest featureRequest, QgsFeatureIds featureIds )
+  : QgsAbstractFeatureIterator( featureRequest ),
+    mFeatureIds( featureIds ),
+    mVectorLayerCache( vlCache )
+{
+  mFeatureIdIterator = featureIds.begin();
+}
+
+bool QgsCachedFeatureIterator::nextFeature( QgsFeature& f )
+{
+  mFeatureIdIterator++;
+
+  if ( mFeatureIdIterator == mFeatureIds.end() )
+  {
+    return false;
+  }
+  else
+  {
+    f = QgsFeature( *mVectorLayerCache->mCache[*mFeatureIdIterator]->feature() );
+    return true;
+  }
+}
+
+bool QgsCachedFeatureIterator::rewind()
+{
+  mFeatureIdIterator = mFeatureIds.begin();
+  return true;
+}
+
+bool QgsCachedFeatureIterator::close()
+{
+  // Nothing to clean...
+  return true;
+}
+
+QgsCachedFeatureWriterIterator::QgsCachedFeatureWriterIterator( QgsVectorLayerCache *vlCache, QgsFeatureRequest featureRequest )
+  : QgsAbstractFeatureIterator( featureRequest ),
+    mVectorLayerCache( vlCache )
+{
+  mFeatIt = vlCache->layer()->dataProvider()->getFeatures( featureRequest );
+}
+
+bool QgsCachedFeatureWriterIterator::nextFeature( QgsFeature& f )
+{
+  if ( mFeatIt.nextFeature( f ) )
+  {
+    // As long as features can be fetched from the provider: Write them to cache
+    mVectorLayerCache->cacheFeature( f );
+    mFids.insert( f.id() );
+    return true;
+  }
+  else
+  {
+    // Once no more features can be fetched: Inform the cache, that
+    // the request has been completed
+    mVectorLayerCache->requestCompleted( mRequest, mFids );
+    return false;
+  }
+}
+
+bool QgsCachedFeatureWriterIterator::rewind()
+{
+  mFids.clear();
+  return mFeatIt.rewind();
+}
+
+bool QgsCachedFeatureWriterIterator::close()
+{
+  return mFeatIt.close();
+}

src/core/qgscachedfeatureiterator.h

@@ -0,0 +1,115 @@
+/***************************************************************************
+    qgscachedfeatureiterator.h
+     --------------------------------------
+    Date                 : 12.2.2013
+    Copyright            : (C) 2013 Matthias Kuhn
+    Email                : matthias dot kuhn at gmx 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 QGSCACHEDFEATUREITERATOR_H
+#define QGSCACHEDFEATUREITERATOR_H
+
+#include "qgsfeature.h"
+#include "qgsfeatureiterator.h"
+
+class QgsVectorLayerCache;
+
+/**
+ * @brief
+ * Delivers features from the cache
+ *
+ */
+class CORE_EXPORT QgsCachedFeatureIterator : public QgsAbstractFeatureIterator
+{
+  public:
+    /**
+     * @brief
+     * This constructor creates a feature iterator, that delivers only cached information, based on the
+     * {@link QgsFeatureIds}. No request is made to the backend.
+     *
+     * @param vlCache          The vector layer cache to use
+     * @param featureRequest   The feature request to answer
+     * @param featureIds       The feature ids to return
+     */
+    QgsCachedFeatureIterator( QgsVectorLayerCache* vlCache, QgsFeatureRequest featureRequest, QgsFeatureIds featureIds );
+
+    /**
+     * @brief
+     *
+     * @param f
+     * @return bool
+     */
+    virtual bool nextFeature( QgsFeature& f );
+
+    /**
+     * @brief
+     *
+     * @return bool
+     */
+    virtual bool rewind();
+
+    /**
+     * @brief
+     *
+     * @return bool
+     */
+    virtual bool close();
+
+  private:
+    QgsFeatureIds mFeatureIds;
+    QgsVectorLayerCache* mVectorLayerCache;
+    QgsFeatureIds::Iterator mFeatureIdIterator;
+};
+
+/**
+ * @brief
+ * Uses another iterator as backend and writes features to the cache
+ *
+ */
+class CORE_EXPORT QgsCachedFeatureWriterIterator : public QgsAbstractFeatureIterator
+{
+  public:
+    /**
+     * @brief
+     * This constructor creates a feature iterator, which queries the backend and caches retrieved features.
+     *
+     * @param vlCache          The vector layer cache to use
+     * @param featureRequest   The feature request to answer
+     */
+    QgsCachedFeatureWriterIterator( QgsVectorLayerCache* vlCache, QgsFeatureRequest featureRequest );
+
+    /**
+     * @brief
+     *
+     * @param f
+     * @return bool
+     */
+    virtual bool nextFeature( QgsFeature& f );
+
+    /**
+     * @brief
+     *
+     * @return bool
+     */
+    virtual bool rewind();
+
+    /**
+     * @brief
+     *
+     * @return bool
+     */
+    virtual bool close();
+
+  private:
+    QgsFeatureIterator mFeatIt;
+    QgsVectorLayerCache* mVectorLayerCache;
+    QgsFeatureIds mFids;
+};
+#endif // QGSCACHEDFEATUREITERATOR_H

src/core/qgscacheindex.cpp

@@ -0,0 +1,31 @@
+/***************************************************************************
+    qgscacheindex.cpp
+     --------------------------------------
+    Date                 : 13.2.2013
+    Copyright            : (C) 2013 Matthias Kuhn
+    Email                : matthias dot kuhn at gmx 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 "qgscacheindex.h"
+#include "qgsfeaturerequest.h"
+
+QgsAbstractCacheIndex::QgsAbstractCacheIndex()
+{
+}
+
+QgsAbstractCacheIndex::~QgsAbstractCacheIndex()
+{
+}
+
+void QgsAbstractCacheIndex::requestCompleted( QgsFeatureRequest featureRequest, QgsFeatureIds fids )
+{
+  Q_UNUSED( featureRequest )
+  Q_UNUSED( fids )
+}

src/core/qgscacheindex.h

@@ -0,0 +1,73 @@
+/***************************************************************************
+    qgscacheindex.h
+     --------------------------------------
+    Date                 : 13.2.2013
+    Copyright            : (C) 2013 Matthias Kuhn
+    Email                : matthias dot kuhn at gmx 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 QGSCACHEINDEX_H
+#define QGSCACHEINDEX_H
+
+#include "qgsfeature.h" // QgsFeatureIds
+
+class QgsFeatureRequest;
+
+/**
+ * @brief
+ * Abstract base class for cache indices
+ */
+
+class QgsAbstractCacheIndex
+{
+  public:
+    QgsAbstractCacheIndex();
+    virtual ~QgsAbstractCacheIndex();
+
+    /**
+     * Is called, whenever a feature is removed from the cache. You should update your indexes, so
+     * they become invalid in case this feature was required to successfuly answer a request.
+     */
+    virtual void flushFeature( const QgsFeatureId fid ) = 0;
+
+    /**
+     * Sometimes, the whole cache changes its state and its easier to just withdraw everything.
+     * In this case, this method is issued. Be sure to clear all cache information in here.
+     */
+    virtual void flush() = 0;
+
+    /**
+     * @brief
+     * Implement this method to update the the indices, in case you need information contained by the request
+     * to properly index. (E.g. spatial index)
+     * Does nothing by default
+     *
+     * @param featureRequest  The feature request that was answered
+     * @param fids            The feature ids that have been returned
+     */
+    virtual void requestCompleted( QgsFeatureRequest featureRequest, QgsFeatureIds fids );
+
+    /**
+     * Is called, when a feature request is issued on a cached layer.
+     * If this cache index is able to completely answer the feature request, it will return true
+     * and write the list of feature ids of cached features to cachedFeatures. If it is not able
+     * it will return false and the cachedFeatures state is undefined.
+     *
+     * @param cachedFeatures   A reference to {@link QgsFeatureIds}, where a list of ids is written to,
+     *                         in case this index is able to answer the request.
+     * @param featureRequest   The feature request, for which this index is queried.
+     *
+     * @return   True, if this index holds the information to answer the request.
+     *
+     */
+    virtual bool getCachedIds( QgsFeatureIds& cachedFeatures, const QgsFeatureRequest& featureRequest ) = 0;
+};
+
+#endif // QGSCACHEINDEX_H

src/core/qgscacheindexfeatureid.cpp

@@ -0,0 +1,24 @@
+/***************************************************************************
+    qgscacheindexfeatureid.cpp
+     --------------------------------------
+    Date                 : 13.2.2013
+    Copyright            : (C) 2013 Matthias Kuhn
+    Email                : matthias dot kuhn at gmx 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 "qgscacheindexfeatureid.h"
+
+QgsCacheIndexFeatureId::QgsCacheIndexFeatureId( QgsCachedVectorLayer* cachedVectorLayer ) :
+  QgsAbstractCacheIndex(),
+  C( cachedVectorLayer )
+{
+
+}
+