fixes #488 - allow StructMeta copyFrom / deepcopyFrom / updateFrom to work on base types as well

Signed-off-by: Rob Ambalu <[email protected]>

Author: robambalu

cpp/csp/engine/Struct.cpp

@@ -231,25 +231,41 @@ void StructMeta::copyFrom( const Struct * src, Struct * dest )
     if( unlikely( src == dest ) )
         return;
 
+    const StructMeta * meta = dest -> meta();
     if( dest -> meta() != src -> meta() && 
         !StructMeta::isDerivedType( src -> meta(), dest -> meta() ) )
+    {
+        if( StructMeta::isDerivedType( dest -> meta(), src -> meta() ) )
+            meta = src -> meta();
+        else
+        {
             CSP_THROW( TypeError, "Attempting to copy from struct type '" << src -> meta() -> name() << "' to struct type '" << dest -> meta() -> name() 
-                       << "'. copy_from may only be used to copy from same type or derived types" );
+                       << "'. copy_from may only be used to copy from struct with a common base type" );
+        }
+    }
 
-    dest -> meta() -> copyFromImpl( src, dest, false );
+    meta -> copyFromImpl( src, dest, false );
 }
 
 void StructMeta::deepcopyFrom( const Struct * src, Struct * dest )
 {
     if( unlikely( src == dest ) )
         return;
 
+    const StructMeta * meta = dest -> meta();
     if( dest -> meta() != src -> meta() && 
         !StructMeta::isDerivedType( src -> meta(), dest -> meta() ) )
+    {
+        if( StructMeta::isDerivedType( dest -> meta(), src -> meta() ) )
+            meta = src -> meta();
+        else
+        {
             CSP_THROW( TypeError, "Attempting to deepcopy from struct type '" << src -> meta() -> name() << "' to struct type '" << dest -> meta() -> name() 
-                       << "'. deepcopy_from may only be used to copy from same type or derived types" );
-
-    dest -> meta() -> copyFromImpl( src, dest, true );
+                       << "'. deepcopy_from may only be used to copy from struct with a common base type" );
+        }
+    }
+    
+    meta -> copyFromImpl( src, dest, true );
 }   
 
 void StructMeta::copyFromImpl( const Struct * src, Struct * dest, bool deepcopy ) const
@@ -291,12 +307,21 @@ void StructMeta::updateFrom( const Struct * src, Struct * dest )
     if( unlikely( src == dest ) )
         return;
 
+    const StructMeta * meta = dest -> meta();
+    
     if( dest -> meta() != src -> meta() && 
         !StructMeta::isDerivedType( src -> meta(), dest -> meta() ) )
+    {
+        if( StructMeta::isDerivedType( dest -> meta(), src -> meta() ) )
+            meta = src -> meta();
+        else
+        {
             CSP_THROW( TypeError, "Attempting to update from struct type '" << src -> meta() -> name() << "' to struct type '" << dest -> meta() -> name() 
-                       << "'. update_from may only be used to update from same type or derived types" );
+                       << "'. update_from may only be used to update from struct with a common base type" );
+        }
+    }
 
-    dest -> meta() -> updateFromImpl( src, dest );
+    meta -> updateFromImpl( src, dest );
 }    
 
 void StructMeta::updateFromImpl( const Struct * src, Struct * dest ) const