[OGR provider] Make extent() return a isNull() rectangle on empty layer (fixes #16721)

rouault · rouault · commit 7d8f3f72d91a · 2017-11-12T15:04:17.000+01:00
diff --git a/src/providers/ogr/qgsogrprovider.cpp b/src/providers/ogr/qgsogrprovider.cpp
@@ -1096,25 +1096,25 @@ QgsRectangle QgsOgrProvider::extent()
     }
 #endif
 
+    mExtent->MinX = std::numeric_limits<double>::max();
+    mExtent->MinY = std::numeric_limits<double>::max();
+    mExtent->MaxX = -std::numeric_limits<double>::max();
+    mExtent->MaxY = -std::numeric_limits<double>::max();
+
     // TODO: This can be expensive, do we really need it!
     if ( ogrLayer == ogrOrigLayer )
     {
       OGR_L_GetExtent( ogrLayer, mExtent, true );
     }
     else
     {
-      mExtent->MinX = std::numeric_limits<double>::max();
-      mExtent->MinY = std::numeric_limits<double>::max();
-      mExtent->MaxX = -std::numeric_limits<double>::max();
-      mExtent->MaxY = -std::numeric_limits<double>::max();
-
       OGRFeatureH f;
 
       OGR_L_ResetReading( ogrLayer );
       while (( f = OGR_L_GetNextFeature( ogrLayer ) ) )
       {
         OGRGeometryH g = OGR_F_GetGeometryRef( f );
-        if ( g )
+        if ( g && !OGR_G_IsEmpty( g ) )
         {
           OGREnvelope env;
           OGR_G_GetEnvelope( g, &env );

Original file line number	Diff line number	Diff line change
`@@ -1096,25 +1096,25 @@ QgsRectangle QgsOgrProvider::extent()`
`1096`	`1096`	`}`
`1097`	`1097`	`#endif`
`1098`	`1098`
	`1099`	`+ mExtent->MinX = std::numeric_limits<double>::max();`
	`1100`	`+ mExtent->MinY = std::numeric_limits<double>::max();`
	`1101`	`+ mExtent->MaxX = -std::numeric_limits<double>::max();`
	`1102`	`+ mExtent->MaxY = -std::numeric_limits<double>::max();`
	`1103`	`+`
`1099`	`1104`	`// TODO: This can be expensive, do we really need it!`
`1100`	`1105`	`if ( ogrLayer == ogrOrigLayer )`
`1101`	`1106`	`{`
`1102`	`1107`	`OGR_L_GetExtent( ogrLayer, mExtent, true );`
`1103`	`1108`	`}`
`1104`	`1109`	`else`
`1105`	`1110`	`{`
`1106`		`- mExtent->MinX = std::numeric_limits<double>::max();`
`1107`		`- mExtent->MinY = std::numeric_limits<double>::max();`
`1108`		`- mExtent->MaxX = -std::numeric_limits<double>::max();`
`1109`		`- mExtent->MaxY = -std::numeric_limits<double>::max();`
`1110`		`-`
`1111`	`1111`	`OGRFeatureH f;`
`1112`	`1112`
`1113`	`1113`	`OGR_L_ResetReading( ogrLayer );`
`1114`	`1114`	`while (( f = OGR_L_GetNextFeature( ogrLayer ) ) )`
`1115`	`1115`	`{`
`1116`	`1116`	`OGRGeometryH g = OGR_F_GetGeometryRef( f );`
`1117`		`- if ( g )`
	`1117`	`+ if ( g && !OGR_G_IsEmpty( g ) )`
`1118`	`1118`	`{`
`1119`	`1119`	`OGREnvelope env;`
`1120`	`1120`	`OGR_G_GetEnvelope( g, &env );`