Class DynamicObject.GetPropertyFlagsNode

java.lang.Object

com.oracle.truffle.api.nodes.Node

com.oracle.truffle.api.object.DynamicObject.GetPropertyFlagsNode

All Implemented Interfaces:

NodeInterface, Cloneable

Enclosing class:

DynamicObject

public abstract static class DynamicObject.GetPropertyFlagsNode
extends Node

Gets the property flags associated with the requested property key.

Since:

25.1

See Also:

• execute(DynamicObject, Object, int)

Nested Class Summary

Nested classes/interfaces inherited from class Node

Node.Child, Node.Children

Method Summary

Modifier and Type	Method	Description
static DynamicObject.GetPropertyFlagsNode	create()
abstract int	execute(DynamicObject receiver, Object key, int defaultValue)	Gets the property flags associated with the requested property key.
static DynamicObject.GetPropertyFlagsNode	getUncached()

Methods inherited from class Node

accept, adoptChildren, atomic, atomic, copy, deepCopy, getChildren, getCost, getDebugProperties, getDescription, getEncapsulatingSourceSection, getLock, getParent, getRootNode, getSourceSection, insert, insert, isAdoptable, isSafelyReplaceableBy, notifyInserted, onReplace, replace, replace, reportPolymorphicSpecialize, reportReplace, toString

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Details

execute

public abstract int execute(DynamicObject receiver,
 Object key,
 int defaultValue)

Gets the property flags associated with the requested property key. Returns the defaultValue if the object contains no such property. If the property exists but no flags were explicitly set, returns the default of 0.

Convenience method equivalent to:

abstract static class GetPropertyEquivalentNode extends Node {
    abstract void execute(DynamicObject receiver, Object key);

    @Specialization
    int doGeneric(MyDynamicObjectSubclass receiver, Symbol key, int defaultValue,
                    @Cached DynamicObject.GetPropertyNode getPropertyNode) {
        Property property = getPropertyNode.execute(receiver, key);
        return property != null ? property.getFlags() : defaultValue;
    }
}

Usage example:

Implementing read-only property check in writeMember:

static final int READ_ONLY = 1;
static final int MISSING = -1;
static final int FROZEN = 1;

@ExportMessage
void writeMember(String member, Object value,
                @Cached @Shared DynamicObject.GetShapeFlagsNode getShapeFlagsNode,
                @Cached @Shared DynamicObject.GetPropertyFlagsNode getPropertyFlagsNode,
                @Cached DynamicObject.PutNode putNode) throws UnknownIdentifierException, UnsupportedMessageException {
    if ((getShapeFlagsNode.execute(this) & FROZEN) == FROZEN) {
        throw UnsupportedMessageException.create();
    }
    int flags = getPropertyFlagsNode.execute(this, member, MISSING);
    if (flags == MISSING) {
        throw UnknownIdentifierException.create(member);
    } else if ((flags & READ_ONLY) == READ_ONLY) {
        throw UnsupportedMessageException.create();
    }
    putNode.execute(this, member, value);
}

@ExportMessage
boolean isMemberModifiable(String member,
                @Cached @Shared DynamicObject.GetShapeFlagsNode getShapeFlagsNode,
                @Cached @Shared DynamicObject.GetPropertyFlagsNode getPropertyFlagsNode) {
    if ((getShapeFlagsNode.execute(this) & FROZEN) == FROZEN) {
        return false;
    }
    int flags = getPropertyFlagsNode.execute(this, member, MISSING);
    return flags != MISSING && (flags & READ_ONLY) == 0;
}

@ExportMessage
boolean isMemberInsertable(String member,
                @Cached @Shared DynamicObject.GetShapeFlagsNode getShapeFlagsNode,
                @Cached @Shared DynamicObject.GetPropertyFlagsNode getPropertyFlagsNode) {
    if ((getShapeFlagsNode.execute(this) & FROZEN) == FROZEN) {
        return false;
    }
    return getPropertyFlagsNode.execute(this, member, MISSING) == MISSING;
}

Member name equality check omitted for brevity.

Parameters:

key - the property key, compared by identity (==), not equality (equals). See DynamicObject for more information.

defaultValue - value to return if no such property exists

Returns:

the property flags if the property exists, else defaultValue

See Also:

• DynamicObject.GetPropertyNode

create

public static DynamicObject.GetPropertyFlagsNode create()

Since:

25.1

getUncached

public static DynamicObject.GetPropertyFlagsNode getUncached()

Since:

25.1