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qgsvectorlayercache.h
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1 /***************************************************************************
2  qgsvectorlayercache.h
3  Cache features of a vector layer
4  -------------------
5  begin : January 2013
6  copyright : (C) Matthias Kuhn
7  email : matthias dot kuhn at gmx dot ch
8 
9  ***************************************************************************
10  * *
11  * This program is free software; you can redistribute it and/or modify *
12  * it under the terms of the GNU General Public License as published by *
13  * the Free Software Foundation; either version 2 of the License, or *
14  * (at your option) any later version. *
15  * *
16  ***************************************************************************/
17 
18 
19 #ifndef QgsVectorLayerCache_H
20 #define QgsVectorLayerCache_H
21 
22 #include <QCache>
23 
24 #include "qgsvectorlayer.h"
25 
28 
38 class CORE_EXPORT QgsVectorLayerCache : public QObject
39 {
40  Q_OBJECT
41 
42  private:
49  {
50  public:
58  : mCache( vlCache )
59  {
60  mFeature = new QgsFeature( feat );
61  }
62 
64  {
65  // That's the reason we need this wrapper:
66  // Inform the cache that this feature has been removed
67  mCache->featureRemoved( mFeature->id() );
68  delete mFeature;
69  }
70 
71  inline const QgsFeature* feature() { return mFeature; }
72 
73  private:
76 
77  friend class QgsVectorLayerCache;
78  };
79 
80  public:
81  QgsVectorLayerCache( QgsVectorLayer* layer, int cacheSize, QObject* parent = NULL );
83 
90  void setCacheSize( int cacheSize );
91 
99  int cacheSize();
100 
106  void setCacheGeometry( bool cacheGeometry );
107 
108 
114  void setCacheSubsetOfAttributes( const QgsAttributeList& attributes );
115 
122  void setCacheAddedAttributes( bool cacheAddedAttributes );
123 
134  void setFullCache( bool fullCache );
135 
144  void addCacheIndex( QgsAbstractCacheIndex *cacheIndex );
145 
156 
162  bool isFidCached( const QgsFeatureId fid );
163 
171  bool featureAtId( QgsFeatureId featureId, QgsFeature &feature, bool skipCache = false );
172 
178  bool removeCachedFeature( QgsFeatureId fid );
179 
184 
185  protected:
194  void requestCompleted( QgsFeatureRequest featureRequest, QgsFeatureIds fids );
195 
203  void featureRemoved( QgsFeatureId fid );
204 
215  bool checkInformationCovered( const QgsFeatureRequest& featureRequest );
216 
217 
218  signals:
219 
229  void progress( int i, bool& cancel );
230 
234  void finished();
235 
241  void cachedLayerDeleted();
242 
247  void attributeValueChanged( const QgsFeatureId& fid, const int& field, const QVariant &value );
248 
256  void featureAdded( QgsFeatureId fid );
257 
258  private slots:
259  void onAttributeValueChanged( QgsFeatureId fid, int field, const QVariant& value );
260  void featureDeleted( QgsFeatureId fid );
261  void onFeatureAdded( QgsFeatureId fid );
262  void attributeAdded( int field );
263  void attributeDeleted( int field );
264  void geometryChanged( QgsFeatureId fid, QgsGeometry& geom );
265  void layerDeleted();
266  void updatedFields();
267 
268  private:
269 
270  inline void cacheFeature( QgsFeature& feat )
271  {
272  QgsCachedFeature* cachedFeature = new QgsCachedFeature( feat, this );
273  mCache.insert( feat.id(), cachedFeature );
274  }
275 
277  QCache< QgsFeatureId, QgsCachedFeature > mCache;
278 
281  QList<QgsAbstractCacheIndex*> mCacheIndices;
282 
284 
287  friend class QgsCachedFeature;
288 };
289 #endif // QgsVectorLayerCache_H
QgsFeatureId id() const
Get the feature id for this feature.
Definition: qgsfeature.cpp:100
Wrapper for iterator of features from vector data provider or vector layer.
QList< QgsAbstractCacheIndex * > mCacheIndices
QgsAttributeList mCachedAttributes
QSet< QgsFeatureId > QgsFeatureIds
Definition: qgsfeature.h:325
bool removeCachedFeature(QgsFeatureId fid)
Removes the feature identified by fid from the cache if present.
bool isFidCached(const QgsFeatureId fid)
Check if a certain feature id is cached.
QgsVectorLayer * layer()
Returns the layer to which this cache belongs.
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:113
QCache< QgsFeatureId, QgsCachedFeature > mCache
void setCacheSubsetOfAttributes(const QgsAttributeList &attributes)
Set the subset of attributes to be cached.
void featureAdded(QgsFeatureId fid)
Is emitted, when a new feature has been added to the layer and this cache.
void attributeAdded(int field)
Uses another iterator as backend and writes features to the cache.
void progress(int i, bool &cancel)
When filling the cache, this signal gets emitted periodically to notify about the progress and to be ...
This class wraps a request for features to a vector layer (or directly its vector data provider)...
QList< int > QgsAttributeList
void featureDeleted(QgsFeatureId fid)
void cachedLayerDeleted()
Is emitted when the cached layer is deleted.
QgsCachedFeature(const QgsFeature &feat, QgsVectorLayerCache *vlCache)
Will create a new cached feature.
void geometryChanged(QgsFeatureId fid, QgsGeometry &geom)
bool checkInformationCovered(const QgsFeatureRequest &featureRequest)
Checks if the information required to complete the request is cached.
This class caches features of a given QgsVectorLayer.
void attributeValueChanged(const QgsFeatureId &fid, const int &field, const QVariant &value)
Is emitted when an attribute is changed.
Abstract base class for cache indices.
Definition: qgscacheindex.h:29
QgsVectorLayer * mLayer
void setCacheGeometry(bool cacheGeometry)
Enable or disable the caching of geometries.
void setFullCache(bool fullCache)
This enables or disables full caching.
bool featureAtId(QgsFeatureId featureId, QgsFeature &feature, bool skipCache=false)
Gets the feature at the given feature id.
void cacheFeature(QgsFeature &feat)
void setCacheSize(int cacheSize)
Sets the maximum number of features to keep in the cache.
void requestCompleted(QgsFeatureRequest featureRequest, QgsFeatureIds fids)
Gets called, whenever the full list of feature ids for a certain request is known.
qint64 QgsFeatureId
Definition: qgsfeature.h:30
This is a wrapper class around a cached QgsFeature, which will inform the cache, when it has been del...
QgsVectorLayerCache(QgsVectorLayer *layer, int cacheSize, QObject *parent=NULL)
Delivers features from the cache.
void featureRemoved(QgsFeatureId fid)
Gets called, whenever a feature has been removed.
int cacheSize()
Returns the maximum number of features this cache will hold.
void onAttributeValueChanged(QgsFeatureId fid, int field, const QVariant &value)
void addCacheIndex(QgsAbstractCacheIndex *cacheIndex)
Adds a QgsAbstractCacheIndex to this cache.
Represents a vector layer which manages a vector based data sets.
QgsFeatureIterator getFeatures(const QgsFeatureRequest &featureRequest=QgsFeatureRequest())
Query this VectorLayerCache for features.
void finished()
When filling the cache, this signal gets emitted once the cache is fully initialized.
void onFeatureAdded(QgsFeatureId fid)
void setCacheAddedAttributes(bool cacheAddedAttributes)
If this is enabled, the subset of cached attributes will automatically be extended to also include ne...
void attributeDeleted(int field)