Class DynamicObject.GetShapeFlagsNode

java.lang.Object

com.oracle.truffle.api.nodes.Node

com.oracle.truffle.api.object.DynamicObject.GetShapeFlagsNode

All Implemented Interfaces:

NodeInterface, Cloneable

Enclosing class:

DynamicObject

public abstract static class DynamicObject.GetShapeFlagsNode
extends Node

Gets the language-specific object shape flags.

Since:

25.1

See Also:

• execute(DynamicObject)

Nested Class Summary

Nested classes/interfaces inherited from class Node

Node.Child, Node.Children

Method Summary

Modifier and Type	Method	Description
static DynamicObject.GetShapeFlagsNode	create()
abstract int	execute(DynamicObject receiver)	Gets the language-specific object shape flags previously set using DynamicObject.SetShapeFlagsNode or Shape.Builder.shapeFlags(int).
static DynamicObject.GetShapeFlagsNode	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)

Gets the language-specific object shape flags previously set using DynamicObject.SetShapeFlagsNode or Shape.Builder.shapeFlags(int). If no shape flags were explicitly set, the default of 0 is returned. These flags may be used to tag objects that possess characteristics that need to be queried efficiently on fast and slow paths. For example, they can be used to mark objects as frozen.

Usage example:

Implementing frozen object 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.

Returns:

shape flags

See Also:

• DynamicObject.SetShapeFlagsNode
• Shape.Builder.shapeFlags(int)
• Shape.getFlags()

create

public static DynamicObject.GetShapeFlagsNode create()

Since:

25.1

getUncached

public static DynamicObject.GetShapeFlagsNode getUncached()

Since:

25.1