ArrayStack: add Clone method (#1304)

* Provide ArrayStack.Clone method

* Clean definition for old syntax.

Co-authored-by: Kyle Sanderson <kyle.leet@gmail.com>

Author: TheByKotik

core/logic/smn_adt_stack.cpp

@@ -83,6 +83,32 @@ static cell_t CreateStack(IPluginContext *pContext, const cell_t *params)
 	return hndl;
 }
 
+static cell_t CloneStack(IPluginContext *pContext, const cell_t *params)
+{
+	CellArray *oldArray;
+	HandleError err;
+	HandleSecurity sec(pContext->GetIdentity(), g_pCoreIdent);
+
+	if ((err = handlesys->ReadHandle(params[1], htCellStack, &sec, (void **)&oldArray)) != HandleError_None)
+	{
+		return pContext->ThrowNativeError("Invalid Handle %x (error: %d)", params[1], err);
+	}
+
+	ICellArray *array = oldArray->clone();
+	if (!array)
+	{
+		return pContext->ThrowNativeError("Failed to clone stack. Out of memory.");
+	}
+
+	Handle_t hndl = handlesys->CreateHandle(htCellStack, array, pContext->GetIdentity(), g_pCoreIdent, NULL);
+	if (!hndl)
+	{
+		delete array;
+	}
+
+	return hndl;
+}
+
 static cell_t PushStackCell(IPluginContext *pContext, const cell_t *params)
 {
 	CellArray *array;
@@ -387,6 +413,7 @@ static cell_t GetStackBlockSize(IPluginContext *pContext, const cell_t *params)
 REGISTER_NATIVES(cellStackNatives)
 {
 	{"CreateStack",					CreateStack},
+	{"CloneStack",					CloneStack},
 	{"IsStackEmpty",				IsStackEmpty},
 	{"PopStackArray",				PopStackArray},
 	{"PopStackCell",				PopStackCell},
@@ -398,6 +425,7 @@ REGISTER_NATIVES(cellStackNatives)
 
 	// Transitional syntax support.
 	{"ArrayStack.ArrayStack",		CreateStack},
+	{"ArrayStack.Clone",			CloneStack},
 	{"ArrayStack.Pop",				ArrayStack_Pop},
 	{"ArrayStack.PopString",		ArrayStack_PopString},
 	{"ArrayStack.PopArray",			ArrayStack_PopArray},

plugins/include/adt_stack.inc

@@ -54,6 +54,14 @@ methodmap ArrayStack < Handle
 	//                     new Array[X][32]
 	public native ArrayStack(int blocksize=1);
 
+	// Clones an stack, returning a new handle with the same size and data.
+	// This should NOT be confused with CloneHandle. This is a completely new
+	// handle with the same data but no relation to the original. It should
+	// closed when no longer needed.
+	//
+	// @return             New handle to the cloned stack object
+	public native ArrayStack Clone();
+
 	// Pushes a value onto the end of the stack, adding a new index.
 	//
 	// This may safely be used even if the stack has a blocksize