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package com.oracle.truffle.js.runtime.builtins;

import static com.oracle.truffle.js.runtime.objects.JSObjectUtil.putConstructorProperty;
import static com.oracle.truffle.js.runtime.objects.JSObjectUtil.putFunctionsFromContainer;

import java.nio.ByteBuffer;

import com.oracle.truffle.api.CallTarget;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.Truffle;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.api.profiles.BranchProfile;
import com.oracle.truffle.api.profiles.ConditionProfile;
import com.oracle.truffle.js.builtins.ArrayBufferFunctionBuiltins;
import com.oracle.truffle.js.builtins.ArrayBufferPrototypeBuiltins;
import com.oracle.truffle.js.runtime.Errors;
import com.oracle.truffle.js.runtime.JSArguments;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.JSContext.BuiltinFunctionKey;
import com.oracle.truffle.js.runtime.JSRealm;
import com.oracle.truffle.js.runtime.JavaScriptRootNode;
import com.oracle.truffle.js.runtime.objects.JSDynamicObject;
import com.oracle.truffle.js.runtime.objects.JSObject;
import com.oracle.truffle.js.runtime.objects.JSObjectUtil;
import com.oracle.truffle.js.runtime.objects.JSShape;
import com.oracle.truffle.js.runtime.objects.Undefined;
import com.oracle.truffle.js.runtime.util.DirectByteBufferHelper;

public final class JSArrayBuffer extends JSAbstractBuffer implements JSConstructorFactory.Default.WithFunctionsAndSpecies, PrototypeSupplier {

    public static final String CLASS_NAME = "ArrayBuffer";
    public static final String PROTOTYPE_NAME = CLASS_NAME + ".prototype";

    public static final JSArrayBuffer HEAP_INSTANCE = new JSArrayBuffer();
    public static final JSArrayBuffer DIRECT_INSTANCE = new JSArrayBuffer();

    private JSArrayBuffer() {
    }

    public static DynamicObject createArrayBuffer(JSContext context, int length) {
        return createArrayBuffer(context, new byte[length]);
    }

    public static DynamicObject createArrayBuffer(JSContext context, byte[] byteArray) {
        JSRealm realm = context.getRealm();
        JSObjectFactory factory = context.getArrayBufferFactory();
        DynamicObject obj = JSArrayBufferObject.createHeapArrayBuffer(factory.getShape(realm), byteArray);
        factory.initProto(obj, realm);
        assert isJSHeapArrayBuffer(obj);
        return context.trackAllocation(obj);
    }

    public static int getDirectByteLength(DynamicObject thisObj) {
        return getDirectByteBuffer(thisObj).capacity();
    }

    public static ByteBuffer getDirectByteBuffer(DynamicObject thisObj) {
        assert isJSDirectArrayBuffer(thisObj) || JSSharedArrayBuffer.isJSSharedArrayBuffer(thisObj);
        return JSArrayBufferObject.getDirectByteBuffer(thisObj);
    }

    public static DynamicObject createDirectArrayBuffer(JSContext context, int length) {
        return createDirectArrayBuffer(context, DirectByteBufferHelper.allocateDirect(length));
    }

    public static DynamicObject createDirectArrayBuffer(JSContext context, ByteBuffer buffer) {
        JSRealm realm = context.getRealm();
        JSObjectFactory factory = context.getDirectArrayBufferFactory();
        DynamicObject obj = JSArrayBufferObject.createDirectArrayBuffer(factory.getShape(realm), buffer);
        factory.initProto(obj, realm);
        assert isJSDirectArrayBuffer(obj);
        return context.trackAllocation(obj);
    }

    @Override
    public DynamicObject createPrototype(JSRealm realm, DynamicObject ctor) {
        JSContext context = realm.getContext();
        DynamicObject arrayBufferPrototype;
        if (context.getEcmaScriptVersion() < 6) {
            Shape protoShape = JSShape.createPrototypeShape(context, HEAP_INSTANCE, realm.getObjectPrototype());
            arrayBufferPrototype = JSArrayBufferObject.createHeapArrayBuffer(protoShape, new byte[0]);
            JSObjectUtil.setOrVerifyPrototype(context, arrayBufferPrototype, realm.getObjectPrototype());
        } else {
            arrayBufferPrototype = JSObjectUtil.createOrdinaryPrototypeObject(realm);
        }

        putConstructorProperty(context, arrayBufferPrototype, ctor);
        putFunctionsFromContainer(realm, arrayBufferPrototype, ArrayBufferPrototypeBuiltins.BUILTINS);

        JSFunctionData byteLengthGetterData = realm.getContext().getOrCreateBuiltinFunctionData(BuiltinFunctionKey.ArrayBufferByteLength, (c) -> {
            return JSFunctionData.createCallOnly(context, createByteLengthGetterCallTarget(c), 0, "get " + BYTE_LENGTH);
        });

        DynamicObject byteLengthGetter = JSFunction.create(realm, byteLengthGetterData);
        JSObjectUtil.putBuiltinAccessorProperty(arrayBufferPrototype, BYTE_LENGTH, byteLengthGetter, Undefined.instance);
        JSObjectUtil.putToStringTag(arrayBufferPrototype, CLASS_NAME);
        return arrayBufferPrototype;
    }

    private static CallTarget createByteLengthGetterCallTarget(JSContext context) {
        return Truffle.getRuntime().createCallTarget(new JavaScriptRootNode(context.getLanguage(), null, null) {
            private final ConditionProfile isArrayBuffer = ConditionProfile.createBinaryProfile();
            private final ConditionProfile isDirectByteBuffer = ConditionProfile.createBinaryProfile();
            private final BranchProfile errorBranch = BranchProfile.create();

            @Override
            public Object execute(VirtualFrame frame) {
                Object obj = JSArguments.getThisObject(frame.getArguments());
                if (JSDynamicObject.isJSDynamicObject(obj)) {
                    DynamicObject buffer = (DynamicObject) obj;
                    if (isArrayBuffer.profile(isJSHeapArrayBuffer(buffer))) {
                        if (!context.getTypedArrayNotDetachedAssumption().isValid() && isDetachedBuffer(buffer)) {
                            return handleDetachedBuffer();
                        }
                        return getByteLength(buffer);
                    } else if (isDirectByteBuffer.profile(isJSDirectArrayBuffer(buffer))) {
                        if (!context.getTypedArrayNotDetachedAssumption().isValid() && isDetachedBuffer(buffer)) {
                            return handleDetachedBuffer();
                        }
                        return getDirectByteLength(buffer);
                    }
                }
                errorBranch.enter();
                throw Errors.createTypeErrorArrayBufferExpected();
            }

            private Object handleDetachedBuffer() {
                if (context.isOptionV8CompatibilityMode()) {
                    return 0;
                } else {
                    throw Errors.createTypeErrorDetachedBuffer();
                }
            }
        });
    }

    @Override
    public Shape makeInitialShape(JSContext context, DynamicObject prototype) {
        if (this == HEAP_INSTANCE) {
            Shape initialShape = JSObjectUtil.getProtoChildShape(prototype, HEAP_INSTANCE, context);
            return initialShape;
        } else {
            assert this == DIRECT_INSTANCE;
            Shape initialShape = JSObjectUtil.getProtoChildShape(prototype, DIRECT_INSTANCE, context);
            return initialShape;
        }
    }

    public static JSConstructor createConstructor(JSRealm realm) {
        return HEAP_INSTANCE.createConstructorAndPrototype(realm, ArrayBufferFunctionBuiltins.BUILTINS);
    }

    @Override
    public String getClassName() {
        return CLASS_NAME;
    }

    @Override
    public String getClassName(DynamicObject object) {
        return getClassName();
    }

    public static boolean isJSHeapArrayBuffer(Object obj) {
        return (obj instanceof JSArrayBufferObject.Heap);
    }

    public static boolean isJSDirectArrayBuffer(Object obj) {
        return (obj instanceof JSArrayBufferObject.Direct);
    }

    public static boolean isJSDirectOrSharedArrayBuffer(Object obj) {
        return isJSDirectArrayBuffer(obj) || JSSharedArrayBuffer.isJSSharedArrayBuffer(obj);
    }

    
ES2015, 24.1.1.2 IsDetachedBuffer.
Warning: This is a slow method! Use the assumption provided in
getContext().getTypedArrayNotDetachedAssumption() for better performance.
/**
     * ES2015, 24.1.1.2 IsDetachedBuffer.
     *
     * Warning: This is a slow method! Use the assumption provided in
     * getContext().getTypedArrayNotDetachedAssumption() for better performance.
     */
    @TruffleBoundary
    public static boolean isDetachedBuffer(DynamicObject arrayBuffer) {
        assert isJSAbstractBuffer(arrayBuffer);
        if (isJSHeapArrayBuffer(arrayBuffer)) {
            return getByteArray(arrayBuffer) == null;
        } else {
            assert isJSDirectOrSharedArrayBuffer(arrayBuffer);
            return getDirectByteBuffer(arrayBuffer) == null;
        }
    }

    
ES2015, 24.1.1.3 DetachArrayBuffer().
/**
     * ES2015, 24.1.1.3 DetachArrayBuffer().
     */
    @TruffleBoundary
    public static void detachArrayBuffer(DynamicObject arrayBuffer) {
        assert isJSAbstractBuffer(arrayBuffer);
        JSObject.getJSContext(arrayBuffer).getTypedArrayNotDetachedAssumption().invalidate("no detached array buffer");
        if (isJSDirectArrayBuffer(arrayBuffer)) {
            ((JSArrayBufferObject.Direct) arrayBuffer).detachArrayBuffer();
        } else {
            ((JSArrayBufferObject.Heap) arrayBuffer).detachArrayBuffer();
        }
    }

    @Override
    public DynamicObject getIntrinsicDefaultProto(JSRealm realm) {
        return realm.getArrayBufferPrototype();
    }
}