/**
* create a CAstNode l representing a loop that traverses the prototype chain from receiver
* searching for the constant property element. update nodeMap to map root to an expression that
* reads the property from the right node.
*
* @param root
* @param receiver
* @param element
* @param context
* @param nodeMap
* @return
*/
private CAstNode makeConstRead(
CAstNode root,
CAstNode receiver,
CAstNode element,
RewriteContext context,
Map<Pair<CAstNode, ExpanderKey>, CAstNode> nodeMap) {
CAstNode get, result;
String receiverTemp = TEMP_NAME + (readTempCounter++);
String elt = (String) element.getValue();
if (elt.equals("prototype") || elt.equals("__proto__")) {
result =
Ast.makeNode(
CAstNode.BLOCK_EXPR,
get = Ast.makeNode(CAstNode.OBJECT_REF, receiver, Ast.makeConstant(elt)));
} else {
if (context.inAssignment()) {
context.setAssign(
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)), Ast.makeConstant(elt));
}
result =
Ast.makeNode(
CAstNode.BLOCK_EXPR,
// declare loop variable and initialize to the receiver
Ast.makeNode(
CAstNode.DECL_STMT,
Ast.makeConstant(new InternalCAstSymbol(receiverTemp, false, false)),
receiver),
Ast.makeNode(
CAstNode.LOOP,
// while the desired property of the loop variable is not
// defined...
Ast.makeNode(
CAstNode.UNARY_EXPR,
CAstOperator.OP_NOT,
Ast.makeNode(
CAstNode.IS_DEFINED_EXPR,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeConstant(elt))),
// set the loop variable to be its prototype
Ast.makeNode(
CAstNode.ASSIGN,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeNode(
CAstNode.OBJECT_REF,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeConstant("__proto__")))),
get =
Ast.makeNode(
CAstNode.OBJECT_REF,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeConstant(elt)));
}
nodeMap.put(Pair.make(root, context.key()), result);
nodeMap.put(Pair.make(root, ExpanderKey.EXTRA), get);
return result;
}
/**
* similar to makeConstRead(), but desired property is some expression instead of a constant
*
* @see #makeConstRead(CAstNode, CAstNode, CAstNode, RewriteContext, Map)
*/
private CAstNode makeVarRead(
CAstNode root,
CAstNode receiver,
CAstNode element,
RewriteContext context,
Map<Pair<CAstNode, ExpanderKey>, CAstNode> nodeMap) {
String receiverTemp = TEMP_NAME + (readTempCounter++);
String elementTemp = TEMP_NAME + (readTempCounter++);
if (context.inAssignment()) {
context.setAssign(
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(elementTemp)));
}
CAstNode get;
CAstNode result =
Ast.makeNode(
CAstNode.BLOCK_EXPR,
Ast.makeNode(
CAstNode.DECL_STMT,
Ast.makeConstant(new InternalCAstSymbol(receiverTemp, false, false)),
receiver),
Ast.makeNode(
CAstNode.DECL_STMT,
Ast.makeConstant(new InternalCAstSymbol(elementTemp, false, false)),
element),
Ast.makeNode(
CAstNode.LOOP,
Ast.makeNode(
CAstNode.UNARY_EXPR,
CAstOperator.OP_NOT,
Ast.makeNode(
CAstNode.IS_DEFINED_EXPR,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(elementTemp)))),
Ast.makeNode(
CAstNode.ASSIGN,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeNode(
CAstNode.OBJECT_REF,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeConstant("__proto__")))),
get =
Ast.makeNode(
CAstNode.OBJECT_REF,
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(receiverTemp)),
Ast.makeNode(CAstNode.VAR, Ast.makeConstant(elementTemp))));
nodeMap.put(Pair.make(root, context.key()), get);
return result;
}
