Replace all Partition object copy assignment (#759726)

Copy assignment of Partition objects is now only performed in a few
places in the Operation and OperationResizeMove classes when updating
the displayed PartitionVector.  (From Refresh_Visual() when each
operation is visually applied to the display_partitions vector; the
new_partition from the operation is copy assigned over the top of the
relevant existing partition in the display_partitions vector).

In general polymorphic copy assignment is complicated [1], and is now
unnecessary given the above limited use.  All that is needed is a way to
polymorphically replace one Partition object with another in a
PartitionVector.

First, prevent further use of Partition object copy assignment by
providing a private declaration and no implementation, so the compiler
enforces this.  Second implement and use PartitionVector method
replace_at() which replaces a pointer to one Partition object with
another at the specified index in the PartitionVector.

[1] The Assignment Operator Revisited
    [Section:] Virtual assignment
    http://icu-project.org/docs/papers/cpp_report/the_assignment_operator_revisited.html

Bug 759726 - Implement Partition object polymorphism

include/Partition.h

@@ -149,6 +149,8 @@ public:
 	Byte_Value sector_size ;  //Sector size of the disk device needed for converting to/from sectors and bytes.
 
 private:
+	Partition & operator=( Partition & rhs );  // Not implemented copy assignment operator
+
 	static void get_usage_triple_helper( Sector stot, Sector s1, Sector s2, Sector s3, int imax, int & i1, int & i2, int & i3 ) ;
 
 	void sort_paths_and_remove_duplicates() ;

include/PartitionVector.h

@@ -71,6 +71,7 @@ public:
 	void clear();
 	void push_back_adopt( Partition * partition );
 	void insert_adopt( iterator position, Partition * partition );
+	void replace_at( size_type n, const Partition * partition );
 
 private:
 	std::vector<Partition *> v;

src/Operation.cc

@@ -115,14 +115,14 @@ void Operation::substitute_new( PartitionVector & partitions )
 		{
 			index = find_index_original( partitions[index_extended].logicals );
 			if ( index >= 0 )
-				partitions[index_extended].logicals[index] = *partition_new;
+				partitions[index_extended].logicals.replace_at( index, partition_new );
 		}
 	}
 	else
 	{
 		index = find_index_original( partitions );
 		if ( index >= 0 )
-			partitions[index] = *partition_new;
+			partitions.replace_at( index, partition_new );
 	}
 }
 
@@ -152,7 +152,7 @@ void Operation::insert_new( PartitionVector & partitions )
 			index = find_index_new( partitions[index_extended].logicals );
 			if ( index >= 0 )
 			{
-				partitions[index_extended].logicals[index] = *partition_new;
+				partitions[index_extended].logicals.replace_at( index, partition_new );
 
 				insert_unallocated( partitions[index_extended].logicals,
 				                    partitions[index_extended].sector_start,
@@ -167,7 +167,7 @@ void Operation::insert_new( PartitionVector & partitions )
 		index = find_index_new( partitions );
 		if ( index >= 0 )
 		{
-			partitions[index] = *partition_new;
+			partitions.replace_at( index, partition_new );
 
 			insert_unallocated( partitions, 0, device.length-1, device.sector_size, false );
 		}

src/OperationResizeMove.cc

@@ -159,7 +159,7 @@ void OperationResizeMove::apply_normal_to_visual( PartitionVector & partitions )
 
 			if ( index >= 0 )
 			{
-				partitions[index_extended].logicals[index] = *partition_new;
+				partitions[index_extended].logicals.replace_at( index, partition_new );
 				remove_adjacent_unallocated( partitions[index_extended].logicals, index );
 
 				insert_unallocated( partitions[index_extended].logicals,
@@ -176,7 +176,7 @@ void OperationResizeMove::apply_normal_to_visual( PartitionVector & partitions )
 
 		if ( index >= 0 )
 		{
-			partitions[index] = *partition_new;
+			partitions.replace_at( index, partition_new );
 			remove_adjacent_unallocated( partitions, index ) ;
 
 			insert_unallocated( partitions, 0, device .length -1, device .sector_size, false ) ;

src/PartitionVector.cc

@@ -83,4 +83,11 @@ void PartitionVector::insert_adopt( iterator position, Partition * partition )
 	v.insert( position, partition );
 }
 
+void PartitionVector::replace_at( size_type n, const Partition * partition )
+{
+	Partition *p = new Partition( *partition );
+	delete v[n];
+	v[n] = p;
+}
+
 } //GParted