QgsFeatureRequest: New filters FilterExpression and FilterFids

qgis · Sep 18, 2013 · 0c90f32 · 0c90f32
1 parent 6d485d9
commit 0c90f32
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Showing 39 changed files with 341 additions and 78 deletions.
diff --git a/python/core/qgsfeatureiterator.sip b/python/core/qgsfeatureiterator.sip
@@ -11,13 +11,18 @@ class QgsAbstractFeatureIterator
     virtual ~QgsAbstractFeatureIterator();
 
     //! fetch next feature, return true on success
-    virtual bool nextFeature( QgsFeature& f ) = 0;
+    virtual bool nextFeature( QgsFeature& f );
     //! reset the iterator to the starting position
     virtual bool rewind() = 0;
     //! end of iterating: free the resources / lock
     virtual bool close() = 0;
 
   protected:
+    virtual bool nextFeatureFilterExpression( QgsFeature &f );
+
+    virtual bool nextFeatureFilterFids( QgsFeature & f );
+
+    virtual bool fetchFeature( QgsFeature& f ) = 0;
     void ref(); // add reference
     void deref(); // remove reference, delete if refs == 0
 };

diff --git a/python/core/qgsfeaturerequest.sip b/python/core/qgsfeaturerequest.sip
@@ -17,9 +17,11 @@ class QgsFeatureRequest
 
     enum FilterType
     {
-      FilterNone,   //!< No filter is applied
-      FilterRect,   //!< Filter using a rectangle
-      FilterFid     //!< Filter using feature ID
+      FilterNone,       //!< No filter is applied
+      FilterRect,       //!< Filter using a rectangle
+      FilterFid,        //!< Filter using feature ID
+      FilterExpression, //!< Filter using expression
+      FilterFids        //!< Filter using feature IDs
     };
 
     //! construct a default request: for all features get attributes and geometries
@@ -40,6 +42,14 @@ class QgsFeatureRequest
     QgsFeatureRequest& setFilterFid( qint64 fid );
     qint64 filterFid() const;
 
+    //! Set feature ID that should be fetched.
+    QgsFeatureRequest& setFilterFids( QgsFeatureIds fids );
+    const QgsFeatureIds& filterFids() const;
+
+    //! Set filter expression. Ownership is taken.
+    QgsFeatureRequest& setFilterExpression( const QString& expression );
+    QgsExpression* filterExpression() const;
+
     //! Set flags that affect how features will be fetched
     QgsFeatureRequest& setFlags( Flags flags );
     const Flags& flags() const;

diff --git a/src/core/qgscachedfeatureiterator.cpp b/src/core/qgscachedfeatureiterator.cpp
@@ -24,7 +24,7 @@ QgsCachedFeatureIterator::QgsCachedFeatureIterator( QgsVectorLayerCache *vlCache
   mFeatureIdIterator = featureIds.begin();
 }
 
-bool QgsCachedFeatureIterator::nextFeature( QgsFeature& f )
+bool QgsCachedFeatureIterator::fetchFeature( QgsFeature& f )
 {
   mFeatureIdIterator++;
 
@@ -58,7 +58,7 @@ QgsCachedFeatureWriterIterator::QgsCachedFeatureWriterIterator( QgsVectorLayerCa
   mFeatIt = vlCache->layer()->getFeatures( featureRequest );
 }
 
-bool QgsCachedFeatureWriterIterator::nextFeature( QgsFeature& f )
+bool QgsCachedFeatureWriterIterator::fetchFeature( QgsFeature& f )
 {
   if ( mFeatIt.nextFeature( f ) )
   {

diff --git a/src/core/qgscachedfeatureiterator.h b/src/core/qgscachedfeatureiterator.h
@@ -46,7 +46,7 @@ class CORE_EXPORT QgsCachedFeatureIterator : public QgsAbstractFeatureIterator
      * @param f
      * @return bool
      */
-    virtual bool nextFeature( QgsFeature& f );
+    virtual bool fetchFeature( QgsFeature& f );
 
     /**
      * @brief
@@ -91,7 +91,7 @@ class CORE_EXPORT QgsCachedFeatureWriterIterator : public QgsAbstractFeatureIter
      * @param f
      * @return bool
      */
-    virtual bool nextFeature( QgsFeature& f );
+    virtual bool fetchFeature( QgsFeature& f );
 
     /**
      * @brief

diff --git a/src/core/qgsexpression.h b/src/core/qgsexpression.h
@@ -29,6 +29,7 @@ class QgsFeature;
 class QgsGeometry;
 class QgsOgcUtils;
 class QgsVectorLayer;
+class QgsVectorDataProvider;
 
 class QDomElement;
 
@@ -535,6 +536,7 @@ class CORE_EXPORT QgsExpression
 
         virtual QStringList referencedColumns() const { return QStringList( mName ); }
         virtual bool needsGeometry() const { return false; }
+
         virtual void accept( Visitor& v ) const { v.visit( *this ); }
 
       protected:

diff --git a/src/core/qgsfeatureiterator.cpp b/src/core/qgsfeatureiterator.cpp
@@ -13,7 +13,7 @@
  *                                                                         *
  ***************************************************************************/
 #include "qgsfeatureiterator.h"
-
+#include "qgslogger.h"
 
 QgsAbstractFeatureIterator::QgsAbstractFeatureIterator( const QgsFeatureRequest& request )
     : mRequest( request )
@@ -26,6 +26,44 @@ QgsAbstractFeatureIterator::~QgsAbstractFeatureIterator()
 {
 }
 
+bool QgsAbstractFeatureIterator::nextFeature( QgsFeature& f )
+{
+  switch ( mRequest.filterType() )
+  {
+    case QgsFeatureRequest::FilterExpression:
+      return nextFeatureFilterExpression( f );
+      break;
+
+    case QgsFeatureRequest::FilterFids:
+      return nextFeatureFilterFids( f );
+      break;
+
+    default:
+      return fetchFeature( f );
+      break;
+  }
+}
+
+bool QgsAbstractFeatureIterator::nextFeatureFilterExpression( QgsFeature& f )
+{
+  while ( fetchFeature( f ) )
+  {
+    if ( mRequest.filterExpression()->evaluate( f ).toBool() )
+      return true;
+  }
+  return false;
+}
+
+bool QgsAbstractFeatureIterator::nextFeatureFilterFids( QgsFeature& f )
+{
+  while ( fetchFeature( f ) )
+  {
+    if ( mRequest.filterFids().contains( f.id() ) )
+      return true;
+  }
+  return false;
+}
+
 void QgsAbstractFeatureIterator::ref()
 {
   refs++;

diff --git a/src/core/qgsfeatureiterator.h b/src/core/qgsfeatureiterator.h
@@ -16,6 +16,7 @@
 #define QGSFEATUREITERATOR_H
 
 #include "qgsfeaturerequest.h"
+#include "qgslogger.h"
 
 
 /** \ingroup core
@@ -31,13 +32,20 @@ class CORE_EXPORT QgsAbstractFeatureIterator
     virtual ~QgsAbstractFeatureIterator();
 
     //! fetch next feature, return true on success
-    virtual bool nextFeature( QgsFeature& f ) = 0;
+    virtual bool nextFeature( QgsFeature& f );
+
     //! reset the iterator to the starting position
     virtual bool rewind() = 0;
     //! end of iterating: free the resources / lock
     virtual bool close() = 0;
 
   protected:
+    virtual bool nextFeatureFilterExpression( QgsFeature &f );
+
+    virtual bool nextFeatureFilterFids( QgsFeature & f );
+
+    virtual bool fetchFeature( QgsFeature& f ) = 0;
+
     QgsFeatureRequest mRequest;
 
     bool mClosed;

diff --git a/src/core/qgsfeaturerequest.cpp b/src/core/qgsfeaturerequest.cpp
@@ -15,38 +15,61 @@
 #include "qgsfeaturerequest.h"
 
 #include "qgsfield.h"
+#include "qgsgeometry.h"
 
 #include <QStringList>
 
 QgsFeatureRequest::QgsFeatureRequest()
     : mFilter( FilterNone )
+    , mFilterExpression( 0 )
     , mFlags( 0 )
 {
 }
 
 QgsFeatureRequest::QgsFeatureRequest( QgsFeatureId fid )
     : mFilter( FilterFid )
     , mFilterFid( fid )
+    , mFilterExpression( 0 )
     , mFlags( 0 )
 {
 }
 
 QgsFeatureRequest::QgsFeatureRequest( const QgsRectangle& rect )
     : mFilter( FilterRect )
     , mFilterRect( rect )
+    , mFilterExpression( 0 )
     , mFlags( 0 )
 {
 }
 
 QgsFeatureRequest::QgsFeatureRequest( const QgsFeatureRequest &rh )
+{
+  operator=( rh );
+}
+
+QgsFeatureRequest& QgsFeatureRequest::operator=( const QgsFeatureRequest & rh )
 {
   mFlags = rh.mFlags;
   mFilter = rh.mFilter;
   mFilterRect = rh.mFilterRect;
   mFilterFid = rh.mFilterFid;
+  mFilterFids = rh.mFilterFids;
+  if ( rh.mFilterExpression )
+  {
+    mFilterExpression = new QgsExpression( rh.mFilterExpression->expression() );
+  }
+  else
+  {
+    mFilterExpression = 0;
+  }
   mAttrs = rh.mAttrs;
+  return *this;
 }
 
+QgsFeatureRequest::~QgsFeatureRequest()
+{
+  delete mFilterExpression;
+}
 
 QgsFeatureRequest& QgsFeatureRequest::setFilterRect( const QgsRectangle& rect )
 {
@@ -62,6 +85,21 @@ QgsFeatureRequest& QgsFeatureRequest::setFilterFid( QgsFeatureId fid )
   return *this;
 }
 
+QgsFeatureRequest&QgsFeatureRequest::setFilterFids( QgsFeatureIds fids )
+{
+  mFilter = FilterFids;
+  mFilterFids = fids;
+  return *this;
+}
+
+QgsFeatureRequest& QgsFeatureRequest::setFilterExpression( const QString& expression )
+{
+  mFilter = FilterExpression;
+  delete mFilterExpression;
+  mFilterExpression = new QgsExpression( expression );
+  return *this;
+}
+
 QgsFeatureRequest& QgsFeatureRequest::setFlags( QgsFeatureRequest::Flags flags )
 {
   mFlags = flags;
@@ -89,3 +127,43 @@ QgsFeatureRequest& QgsFeatureRequest::setSubsetOfAttributes( const QStringList&
 
   return *this;
 }
+
+bool QgsFeatureRequest::acceptFeature( const QgsFeature& feature )
+{
+  switch ( mFilter )
+  {
+    case QgsFeatureRequest::FilterNone:
+      return true;
+      break;
+
+    case QgsFeatureRequest::FilterRect:
+      if ( feature.geometry() && feature.geometry()->intersects( mFilterRect ) )
+        return true;
+      else
+        return false;
+      break;
+
+    case QgsFeatureRequest::FilterFid:
+      if ( feature.id () == mFilterFid )
+        return true;
+      else
+        return false;
+      break;
+
+    case QgsFeatureRequest::FilterExpression:
+      if ( mFilterExpression->evaluate( feature ).toBool() )
+        return true;
+      else
+        return false;
+      break;
+
+    case QgsFeatureRequest::FilterFids:
+      if ( mFilterFids.contains ( feature.id () ) )
+        return true;
+      else
+        return false;
+      break;
+  }
+
+  return true;
+}
diff --git a/src/core/qgsfeaturerequest.h b/src/core/qgsfeaturerequest.h
@@ -19,6 +19,7 @@
 
 #include "qgsfeature.h"
 #include "qgsrectangle.h"
+#include "qgsexpression.h"
 
 #include <QList>
 typedef QList<int> QgsAttributeList;
@@ -66,9 +67,11 @@ class CORE_EXPORT QgsFeatureRequest
 
     enum FilterType
     {
-      FilterNone,   //!< No filter is applied
-      FilterRect,   //!< Filter using a rectangle
-      FilterFid     //!< Filter using feature ID
+      FilterNone,       //!< No filter is applied
+      FilterRect,       //!< Filter using a rectangle
+      FilterFid,        //!< Filter using feature ID
+      FilterExpression, //!< Filter using expression
+      FilterFids        //!< Filter using feature ID's
     };
 
     //! construct a default request: for all features get attributes and geometries
@@ -80,6 +83,10 @@ class CORE_EXPORT QgsFeatureRequest
     //! copy constructor
     QgsFeatureRequest( const QgsFeatureRequest& rh );
 
+    QgsFeatureRequest& operator=( const QgsFeatureRequest& rh );
+
+    ~QgsFeatureRequest();
+
     FilterType filterType() const { return mFilter; }
 
     //! Set rectangle from which features will be taken. Empty rectangle removes the filter.
@@ -91,6 +98,14 @@ class CORE_EXPORT QgsFeatureRequest
     QgsFeatureRequest& setFilterFid( QgsFeatureId fid );
     const QgsFeatureId& filterFid() const { return mFilterFid; }
 
+    //! Set feature ID that should be fetched.
+    QgsFeatureRequest& setFilterFids( QgsFeatureIds fids );
+    const QgsFeatureIds& filterFids() const { return mFilterFids; }
+
+    //! Set filter expression. {@see QgsExpression}
+    QgsFeatureRequest& setFilterExpression( const QString& expression );
+    QgsExpression* filterExpression() const { return mFilterExpression; }
+
     //! Set flags that affect how features will be fetched
     QgsFeatureRequest& setFlags( Flags flags );
     const Flags& flags() const { return mFlags; }
@@ -102,6 +117,17 @@ class CORE_EXPORT QgsFeatureRequest
 
     //! Set a subset of attributes by names that will be fetched
     QgsFeatureRequest& setSubsetOfAttributes( const QStringList& attrNames, const QgsFields& fields );
+
+    /** 
+     * Check if a feature is accepted by this requests filter
+     *
+     * @param feature  The feature which will be tested
+     *
+     * @return true, if the filter accepts the feature
+     *
+     * @note added in 2.1
+     */
+    bool acceptFeature( const QgsFeature& feature );
 
     // TODO: in future
     // void setFilterExpression(const QString& expression); // using QgsExpression
@@ -112,6 +138,8 @@ class CORE_EXPORT QgsFeatureRequest
     FilterType mFilter;
     QgsRectangle mFilterRect;
     QgsFeatureId mFilterFid;
+    QgsFeatureIds mFilterFids;
+    QgsExpression* mFilterExpression;
     Flags mFlags;
     QgsAttributeList mAttrs;
 };