public override AstNode Visit(UsingObjectStatement node)
{
// Push the scope.
PushScope(node.GetScope());
// Visit the declarations.
LocalVariablesDeclaration decls = node.GetLocals();
decls.Accept(this);
// Visit the children.
VisitList(node.GetChildren());
// Pop the scope.
PopScope();
return node;
}
public override AstNode Visit(UsingObjectStatement node)
{
// Create the using lexical scope.
LexicalScope blockScope = CreateLexicalScope(node);
node.SetScope(blockScope);
// Push the scope.
PushScope(blockScope);
// Get the local declarations.
LocalVariablesDeclaration decls = node.GetLocals();
decls.Accept(this);
// Check if disposing or deleting.
IChelaType varType = decls.GetNodeType();
bool pointer = varType.IsPointer();
if(!pointer)
{
// Make sure it could implement IDisposable.
varType = DeReferenceType(varType);
if(!varType.IsStructure() && !varType.IsClass() && !varType.IsReference())
Error(node, "cannot dispose object that isn't a structure, class or interface.");
// Make sure it does implement IDisposable.
Structure building = (Structure) varType;
Structure idisposable = currentModule.GetLangMember("IDisposable") as Interface;
if(idisposable == null)
Error(node, "couldn't find IDisposable");
if(building != idisposable && !building.Implements(idisposable))
Error(node, "object doesn't implement IDisposable.");
}
// Build the finally clause.
TokenPosition position = node.GetPosition();
AstNode finallyChildren = null;
AstNode lastChild = null;
AstNode decl = decls.GetDeclarations();
while(decl != null)
{
AstNode disposeStmnt = null;
if(pointer)
{
// Delete the variable
Expression variable = new VariableReference(decl.GetName(), position);
disposeStmnt = new DeleteStatement(variable, position);
}
else
{
// Call the variable dispose.
Expression functionExpr = new MemberAccess(new VariableReference(decl.GetName(), position), "Dispose", position);
Expression callExpr = new CallExpression(functionExpr, null, position);
disposeStmnt = new ExpressionStatement(callExpr, position);
}
// If not null.
Expression notNull = new BinaryOperation(BinaryOperation.OpNEQ, new VariableReference(decl.GetName(), position), new NullConstant(position), position);
IfStatement ifStmnt = new IfStatement(notNull, disposeStmnt, null, position);
// Link the call.
if(lastChild == null)
{
finallyChildren = lastChild = ifStmnt;
}
else
{
lastChild.SetNext(ifStmnt);
lastChild = ifStmnt;
}
// Dispose the next declaration.
decl = decl.GetNext();
}
// Build the try-finally.
FinallyStatement finallyClause = new FinallyStatement(finallyChildren, position);
TryStatement tryStatement = new TryStatement(node.GetChildren(), null, finallyClause, position);
// Substitute the children with the try.
node.SetChildren(tryStatement);
// Visit the block children.
VisitList(node.GetChildren());
// Restore the scope.
PopScope();
return node;
}