Merge pull request #5986 from nyalldawson/geometry_equals

Refine geometry equals checks

doc/api_break.dox

@@ -1354,6 +1354,8 @@ maintains Z or M dimensions from the input points and is more efficient.
 - exportToWkt() was renamed to asWkt()
 - exportToGeoJSON() was renamed to asJson()
 - closestSegmentWithContext() now returns an extra value, indicating whether the point is to the left of the geometry
+- equals() now performs a fast, strict equality check, where geometries are considered equal only if they have the
+exact same type, vertices and order. The slower topological test can be performed by calling isGeosEqual instead.
 
 
 QgsGeometryAnalyzer        {#qgis_api_break_3_0_QgsGeometryAnalyzer}

python/core/geometry/qgsabstractgeometry.sip

@@ -72,6 +72,9 @@ Constructor for QgsAbstractGeometry.
     virtual ~QgsAbstractGeometry();
     QgsAbstractGeometry( const QgsAbstractGeometry &geom );
 
+    virtual bool operator==( const QgsAbstractGeometry &other ) const = 0;
+    virtual bool operator!=( const QgsAbstractGeometry &other ) const = 0;
+
     virtual QgsAbstractGeometry *clone() const = 0 /Factory/;
 %Docstring
 Clones the geometry by performing a deep copy

python/core/geometry/qgscircularstring.sip

@@ -25,9 +25,7 @@ class QgsCircularString: QgsCurve
   public:
     QgsCircularString();
 
-    virtual bool operator==( const QgsCurve &other ) const;
-
-    virtual bool operator!=( const QgsCurve &other ) const;
+    virtual bool equals( const QgsCurve &other ) const;
 
 
     virtual QString geometryType() const;

python/core/geometry/qgscompoundcurve.sip

@@ -25,9 +25,7 @@ class QgsCompoundCurve: QgsCurve
     QgsCompoundCurve( const QgsCompoundCurve &curve );
     ~QgsCompoundCurve();
 
-    virtual bool operator==( const QgsCurve &other ) const;
-
-    virtual bool operator!=( const QgsCurve &other ) const;
+    virtual bool equals( const QgsCurve &other ) const;
 
 
     virtual QString geometryType() const;

python/core/geometry/qgscurve.sip

@@ -28,8 +28,17 @@ class QgsCurve: QgsAbstractGeometry
 Constructor for QgsCurve.
 %End
 
-    virtual bool operator==( const QgsCurve &other ) const = 0;
-    virtual bool operator!=( const QgsCurve &other ) const = 0;
+    virtual bool equals( const QgsCurve &other ) const = 0;
+%Docstring
+Checks whether this curve exactly equals another curve.
+
+.. versionadded:: 3.0
+%End
+
+    virtual bool operator==( const QgsAbstractGeometry &other ) const;
+
+    virtual bool operator!=( const QgsAbstractGeometry &other ) const;
+
 
     virtual QgsCurve *clone() const = 0 /Factory/;
 

python/core/geometry/qgscurvepolygon.sip

@@ -25,8 +25,10 @@ class QgsCurvePolygon: QgsSurface
     QgsCurvePolygon();
     QgsCurvePolygon( const QgsCurvePolygon &p );
 
-    bool operator==( const QgsCurvePolygon &other ) const;
-    bool operator!=( const QgsCurvePolygon &other ) const;
+    virtual bool operator==( const QgsAbstractGeometry &other ) const;
+
+    virtual bool operator!=( const QgsAbstractGeometry &other ) const;
+
 
     ~QgsCurvePolygon();
 

python/core/geometry/qgsgeometry.sip

@@ -247,13 +247,46 @@ return true for isEmpty().
     bool isMultipart() const;
 %Docstring
 Returns true if WKB of the geometry is of WKBMulti* type
+%End
+
+    bool equals( const QgsGeometry &geometry ) const;
+%Docstring
+Test if this geometry is exactly equal to another ``geometry``.
+
+This is a strict equality check, where the underlying geometries must
+have exactly the same type, component vertices and vertex order.
+
+Calling this method is dramatically faster than the topological
+equality test performed by isGeosEqual().
+
+.. note::
+
+   Comparing two null geometries will return false.
+
+.. versionadded:: 1.5
+
+.. seealso:: :py:func:`isGeosEqual()`
 %End
 
     bool isGeosEqual( const QgsGeometry & ) const;
 %Docstring
-Compares the geometry with another geometry using GEOS
+Compares the geometry with another geometry using GEOS.
+
+This method performs a slow, topological check, where geometries
+are considered equal if all of the their component edges overlap. E.g.
+lines with the same vertex locations but opposite direction will be
+considered equal by this method.
+
+Consider using the much faster, stricter equality test performed
+by equals() instead.
+
+.. note::
+
+   Comparing two null geometries will return false.
 
 .. versionadded:: 1.5
+
+.. seealso:: :py:func:`equals()`
 %End
 
     bool isGeosValid() const;
@@ -749,13 +782,6 @@ Tests for if geometry is contained in another (uses GEOS)
 %Docstring
 Tests for if geometry is disjoint of another (uses GEOS)
 
-.. versionadded:: 1.5
-%End
-
-    bool equals( const QgsGeometry &geometry ) const;
-%Docstring
-Test for if geometry equals another (uses GEOS)
-
 .. versionadded:: 1.5
 %End
 

python/core/geometry/qgsgeometrycollection.sip

@@ -27,6 +27,11 @@ class QgsGeometryCollection: QgsAbstractGeometry
     QgsGeometryCollection( const QgsGeometryCollection &c );
     ~QgsGeometryCollection();
 
+    virtual bool operator==( const QgsAbstractGeometry &other ) const;
+
+    virtual bool operator!=( const QgsAbstractGeometry &other ) const;
+
+
     virtual QgsGeometryCollection *clone() const /Factory/;
 
 

python/core/geometry/qgslinestring.sip

@@ -57,9 +57,7 @@ or repeatedly calling addVertex()
 .. versionadded:: 3.0
 %End
 
-    virtual bool operator==( const QgsCurve &other ) const;
-
-    virtual bool operator!=( const QgsCurve &other ) const;
+    virtual bool equals( const QgsCurve &other ) const;
 
 
     QgsPoint pointN( int i ) const;

python/core/geometry/qgspoint.sip

@@ -85,8 +85,10 @@ Construct a QgsPoint from a QPointF
 %End
 
 
-    bool operator==( const QgsPoint &pt ) const;
-    bool operator!=( const QgsPoint &pt ) const;
+    virtual bool operator==( const QgsAbstractGeometry &other ) const;
+
+    virtual bool operator!=( const QgsAbstractGeometry &other ) const;
+
 
     double x() const;
 %Docstring

src/analysis/processing/qgsalgorithmsplitwithlines.cpp

@@ -202,7 +202,7 @@ QVariantMap QgsSplitWithLinesAlgorithm::processAlgorithm( const QVariantMap &par
               // between geometry and splitLine, only the first one is considered.
               if ( result == QgsGeometry::Success ) // split occurred
               {
-                if ( inGeom.equals( before ) )
+                if ( inGeom.isGeosEqual( before ) )
                 {
                   // bug in splitGeometry: sometimes it returns 0 but
                   // the geometry is unchanged

src/core/geometry/qgsabstractgeometry.h

@@ -110,6 +110,9 @@ class CORE_EXPORT QgsAbstractGeometry
     QgsAbstractGeometry( const QgsAbstractGeometry &geom );
     QgsAbstractGeometry &operator=( const QgsAbstractGeometry &geom );
 
+    virtual bool operator==( const QgsAbstractGeometry &other ) const = 0;
+    virtual bool operator!=( const QgsAbstractGeometry &other ) const = 0;
+
     /**
      * Clones the geometry by performing a deep copy
      */

src/core/geometry/qgscircularstring.cpp

@@ -33,7 +33,7 @@ QgsCircularString::QgsCircularString()
   mWkbType = QgsWkbTypes::CircularString;
 }
 
-bool QgsCircularString::operator==( const QgsCurve &other ) const
+bool QgsCircularString::equals( const QgsCurve &other ) const
 {
   const QgsCircularString *otherLine = dynamic_cast< const QgsCircularString * >( &other );
   if ( !otherLine )
@@ -61,11 +61,6 @@ bool QgsCircularString::operator==( const QgsCurve &other ) const
   return true;
 }
 
-bool QgsCircularString::operator!=( const QgsCurve &other ) const
-{
-  return !operator==( other );
-}
-
 QgsCircularString *QgsCircularString::createEmptyWithSameType() const
 {
   auto result = qgis::make_unique< QgsCircularString >();

src/core/geometry/qgscircularstring.h

@@ -36,8 +36,7 @@ class CORE_EXPORT QgsCircularString: public QgsCurve
   public:
     QgsCircularString();
 
-    bool operator==( const QgsCurve &other ) const override;
-    bool operator!=( const QgsCurve &other ) const override;
+    bool equals( const QgsCurve &other ) const override;
 
     QString geometryType() const override;
     int dimension() const override;

src/core/geometry/qgscompoundcurve.cpp

@@ -35,7 +35,7 @@ QgsCompoundCurve::~QgsCompoundCurve()
   clear();
 }
 
-bool QgsCompoundCurve::operator==( const QgsCurve &other ) const
+bool QgsCompoundCurve::equals( const QgsCurve &other ) const
 {
   const QgsCompoundCurve *otherCurve = qgsgeometry_cast< const QgsCompoundCurve * >( &other );
   if ( !otherCurve )
@@ -56,11 +56,6 @@ bool QgsCompoundCurve::operator==( const QgsCurve &other ) const
   return true;
 }
 
-bool QgsCompoundCurve::operator!=( const QgsCurve &other ) const
-{
-  return !operator==( other );
-}
-
 QgsCompoundCurve *QgsCompoundCurve::createEmptyWithSameType() const
 {
   auto result = qgis::make_unique< QgsCompoundCurve >();

src/core/geometry/qgscompoundcurve.h

@@ -36,8 +36,7 @@ class CORE_EXPORT QgsCompoundCurve: public QgsCurve
     QgsCompoundCurve &operator=( const QgsCompoundCurve &curve );
     ~QgsCompoundCurve() override;
 
-    bool operator==( const QgsCurve &other ) const override;
-    bool operator!=( const QgsCurve &other ) const override;
+    bool equals( const QgsCurve &other ) const override;
 
     QString geometryType() const override;
     int dimension() const override;

src/core/geometry/qgscurve.cpp

@@ -22,6 +22,20 @@
 #include "qgspoint.h"
 #include "qgsmultipoint.h"
 
+bool QgsCurve::operator==( const QgsAbstractGeometry &other ) const
+{
+  const QgsCurve *otherCurve = qgsgeometry_cast< const QgsCurve * >( &other );
+  if ( !otherCurve )
+    return false;
+
+  return equals( *otherCurve );
+}
+
+bool QgsCurve::operator!=( const QgsAbstractGeometry &other ) const
+{
+  return !operator==( other );
+}
+
 bool QgsCurve::isClosed() const
 {
   if ( numPoints() == 0 )

src/core/geometry/qgscurve.h

@@ -41,8 +41,14 @@ class CORE_EXPORT QgsCurve: public QgsAbstractGeometry
      */
     QgsCurve() = default;
 
-    virtual bool operator==( const QgsCurve &other ) const = 0;
-    virtual bool operator!=( const QgsCurve &other ) const = 0;
+    /**
+     * Checks whether this curve exactly equals another curve.
+     * \since QGIS 3.0
+     */
+    virtual bool equals( const QgsCurve &other ) const = 0;
+
+    bool operator==( const QgsAbstractGeometry &other ) const override;
+    bool operator!=( const QgsAbstractGeometry &other ) const override;
 
     QgsCurve *clone() const override = 0 SIP_FACTORY;
 

src/core/geometry/qgscurvepolygon.cpp

@@ -90,40 +90,44 @@ QgsCurvePolygon &QgsCurvePolygon::operator=( const QgsCurvePolygon &p )
   return *this;
 }
 
-bool QgsCurvePolygon::operator==( const QgsCurvePolygon &other ) const
+bool QgsCurvePolygon::operator==( const QgsAbstractGeometry &other ) const
 {
+  const QgsCurvePolygon *otherPolygon = qgsgeometry_cast< const QgsCurvePolygon * >( &other );
+  if ( !otherPolygon )
+    return false;
+
   //run cheap checks first
-  if ( mWkbType != other.mWkbType )
+  if ( mWkbType != otherPolygon->mWkbType )
     return false;
 
-  if ( ( !mExteriorRing && other.mExteriorRing ) || ( mExteriorRing && !other.mExteriorRing ) )
+  if ( ( !mExteriorRing && otherPolygon->mExteriorRing ) || ( mExteriorRing && !otherPolygon->mExteriorRing ) )
     return false;
 
-  if ( mInteriorRings.count() != other.mInteriorRings.count() )
+  if ( mInteriorRings.count() != otherPolygon->mInteriorRings.count() )
     return false;
 
   // compare rings
-  if ( mExteriorRing && other.mExteriorRing )
+  if ( mExteriorRing && otherPolygon->mExteriorRing )
   {
-    if ( *mExteriorRing != *other.mExteriorRing )
+    if ( *mExteriorRing != *otherPolygon->mExteriorRing )
       return false;
   }
 
   for ( int i = 0; i < mInteriorRings.count(); ++i )
   {
-    if ( ( !mInteriorRings.at( i ) && other.mInteriorRings.at( i ) ) ||
-         ( mInteriorRings.at( i ) && !other.mInteriorRings.at( i ) ) )
+    if ( ( !mInteriorRings.at( i ) && otherPolygon->mInteriorRings.at( i ) ) ||
+         ( mInteriorRings.at( i ) && !otherPolygon->mInteriorRings.at( i ) ) )
       return false;
 
-    if ( mInteriorRings.at( i ) && other.mInteriorRings.at( i ) &&
-         *mInteriorRings.at( i ) != *other.mInteriorRings.at( i ) )
+    if ( mInteriorRings.at( i ) && otherPolygon->mInteriorRings.at( i ) &&
+         *mInteriorRings.at( i ) != *otherPolygon->mInteriorRings.at( i ) )
       return false;
   }
 
   return true;
 }
 
-bool QgsCurvePolygon::operator!=( const QgsCurvePolygon &other ) const
+bool QgsCurvePolygon::operator!=( const QgsAbstractGeometry &other ) const
 {
   return !operator==( other );
 }

src/core/geometry/qgscurvepolygon.h

@@ -38,8 +38,8 @@ class CORE_EXPORT QgsCurvePolygon: public QgsSurface
     QgsCurvePolygon( const QgsCurvePolygon &p );
     QgsCurvePolygon &operator=( const QgsCurvePolygon &p );
 
-    bool operator==( const QgsCurvePolygon &other ) const;
-    bool operator!=( const QgsCurvePolygon &other ) const;
+    bool operator==( const QgsAbstractGeometry &other ) const override;
+    bool operator!=( const QgsAbstractGeometry &other ) const override;
 
     ~QgsCurvePolygon() override;
 

src/core/geometry/qgsgeometry.cpp

@@ -1147,9 +1147,12 @@ bool QgsGeometry::equals( const QgsGeometry &geometry ) const
     return false;
   }
 
-  QgsGeos geos( d->geometry.get() );
-  mLastError.clear();
-  return geos.isEqual( geometry.d->geometry.get(), &mLastError );
+  // fast check - are they shared copies of the same underlying geometry?
+  if ( d == geometry.d )
+    return true;
+
+  // slower check - actually test the geometries
+  return *d->geometry.get() == *geometry.d->geometry.get();
 }
 
 bool QgsGeometry::touches( const QgsGeometry &geometry ) const