/*
 * Copyright (c) 2017, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.svm.jni.hosted;

// Checkstyle: allow reflection

import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;

import org.graalvm.compiler.core.common.type.ObjectStamp;
import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.core.common.type.TypeReference;
import org.graalvm.compiler.debug.DebugContext;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.FixedGuardNode;
import org.graalvm.compiler.nodes.InvokeWithExceptionNode;
import org.graalvm.compiler.nodes.LogicNode;
import org.graalvm.compiler.nodes.PiNode;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.java.InstanceOfNode;
import org.graalvm.compiler.nodes.java.MonitorEnterNode;
import org.graalvm.compiler.nodes.java.MonitorExitNode;
import org.graalvm.compiler.nodes.java.MonitorIdNode;

import com.oracle.graal.pointsto.infrastructure.WrappedJavaMethod;
import com.oracle.graal.pointsto.meta.HostedProviders;
import com.oracle.svm.core.graal.nodes.CGlobalDataLoadAddressNode;
import com.oracle.svm.core.hub.DynamicHub;
import com.oracle.svm.core.meta.SubstrateObjectConstant;
import com.oracle.svm.core.thread.VMThreads.StatusSupport;
import com.oracle.svm.hosted.annotation.CustomSubstitutionMethod;
import com.oracle.svm.hosted.code.SimpleSignature;
import com.oracle.svm.jni.access.JNIAccessFeature;
import com.oracle.svm.jni.access.JNINativeLinkage;
import com.oracle.svm.jni.nativeapi.JNIEnvironment;
import com.oracle.svm.jni.nativeapi.JNIObjectHandle;

import jdk.vm.ci.meta.Constant;
import jdk.vm.ci.meta.DeoptimizationAction;
import jdk.vm.ci.meta.DeoptimizationReason;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.JavaType;
import jdk.vm.ci.meta.ResolvedJavaMethod;
import jdk.vm.ci.meta.ResolvedJavaType;
import jdk.vm.ci.meta.Signature;

Generated code for calling a specific native method from Java code. The wrapper takes care of
transitioning to native code and back to Java, and if required, for boxing object arguments in
handles and for unboxing an object return value.
/**
 * Generated code for calling a specific native method from Java code. The wrapper takes care of
 * transitioning to native code and back to Java, and if required, for boxing object arguments in
 * handles and for unboxing an object return value.
 */
class JNINativeCallWrapperMethod extends CustomSubstitutionMethod {
    private final JNINativeLinkage linkage;

    JNINativeCallWrapperMethod(ResolvedJavaMethod method) {
        super(method);
        linkage = createLinkage(method);
    }

    private static JNINativeLinkage createLinkage(ResolvedJavaMethod method) {
        ResolvedJavaMethod unwrapped = method;
        while (unwrapped instanceof WrappedJavaMethod) {
            unwrapped = ((WrappedJavaMethod) unwrapped).getWrapped();
        }
        String className = unwrapped.getDeclaringClass().getName();
        String descriptor = unwrapped.getSignature().toMethodDescriptor();
        return JNIAccessFeature.singleton().makeLinkage(className, unwrapped.getName(), descriptor);
    }

    @Override
    public boolean isSynthetic() {
        return true;
    }

    @Override
    public int getModifiers() {
        final int synthetic = 0x1000;
        // A synchronized method requires some special handling. Instead, if the wrapped method is
        // declared synchronized, we add graph nodes to lock and unlock accordingly.
        return (getOriginal().getModifiers() | synthetic) & ~(Modifier.NATIVE | Modifier.SYNCHRONIZED);
    }

    @Override
    public StructuredGraph buildGraph(DebugContext debug, ResolvedJavaMethod method, HostedProviders providers, Purpose purpose) {
        JNIGraphKit kit = new JNIGraphKit(debug, providers, method);
        StructuredGraph graph = kit.getGraph();

        InvokeWithExceptionNode handleFrame = kit.nativeCallPrologue();

        ValueNode callAddress;
        if (linkage.isBuiltInFunction()) {
            callAddress = kit.unique(new CGlobalDataLoadAddressNode(linkage.getBuiltInAddress()));
        } else {
            callAddress = kit.nativeCallAddress(kit.createObject(linkage));
        }

        ValueNode environment = kit.environment();

        JavaType javaReturnType = method.getSignature().getReturnType(null);
        JavaType[] javaArgumentTypes = method.toParameterTypes();
        List<ValueNode> javaArguments = kit.loadArguments(javaArgumentTypes);

        List<ValueNode> jniArguments = new ArrayList<>(2 + javaArguments.size());
        List<JavaType> jniArgumentTypes = new ArrayList<>(jniArguments.size());
        JavaType environmentType = providers.getMetaAccess().lookupJavaType(JNIEnvironment.class);
        JavaType objectHandleType = providers.getMetaAccess().lookupJavaType(JNIObjectHandle.class);
        jniArguments.add(environment);
        jniArgumentTypes.add(environmentType);
        if (method.isStatic()) {
            JavaConstant clazz = providers.getConstantReflection().asJavaClass(method.getDeclaringClass());
            ConstantNode clazzNode = ConstantNode.forConstant(clazz, providers.getMetaAccess(), graph);
            ValueNode box = kit.boxObjectInLocalHandle(clazzNode);
            jniArguments.add(box);
            jniArgumentTypes.add(objectHandleType);
        }
        for (int i = 0; i < javaArguments.size(); i++) {
            ValueNode arg = javaArguments.get(i);
            JavaType argType = javaArgumentTypes[i];
            if (javaArgumentTypes[i].getJavaKind().isObject()) {
                ValueNode obj = javaArguments.get(i);
                arg = kit.boxObjectInLocalHandle(obj);
                argType = objectHandleType;
            }
            jniArguments.add(arg);
            jniArgumentTypes.add(argType);
        }
        assert jniArguments.size() == jniArgumentTypes.size();
        JavaType jniReturnType = javaReturnType;
        if (jniReturnType.getJavaKind().isObject()) {
            jniReturnType = objectHandleType;
        }

        if (getOriginal().isSynchronized()) {
            ValueNode monitorObject;
            if (method.isStatic()) {
                Constant hubConstant = providers.getConstantReflection().asObjectHub(method.getDeclaringClass());
                DynamicHub hub = (DynamicHub) SubstrateObjectConstant.asObject(hubConstant);
                monitorObject = ConstantNode.forConstant(SubstrateObjectConstant.forObject(hub), providers.getMetaAccess(), graph);
            } else {
                monitorObject = javaArguments.get(0);
            }
            MonitorIdNode monitorId = graph.add(new MonitorIdNode(kit.getFrameState().lockDepth(false)));
            MonitorEnterNode monitorEnter = kit.append(new MonitorEnterNode(monitorObject, monitorId));
            kit.getFrameState().pushLock(monitorEnter.object(), monitorEnter.getMonitorId());
            monitorEnter.setStateAfter(kit.getFrameState().create(kit.bci(), monitorEnter));
        }

        kit.getFrameState().clearLocals();

        Signature jniSignature = new SimpleSignature(jniArgumentTypes, jniReturnType);
        ValueNode returnValue = kit.createCFunctionCall(callAddress, jniArguments, jniSignature, StatusSupport.STATUS_IN_NATIVE, false);

        if (getOriginal().isSynchronized()) {
            MonitorIdNode monitorId = kit.getFrameState().peekMonitorId();
            ValueNode monitorObject = kit.getFrameState().popLock();
            MonitorExitNode monitorExit = kit.append(new MonitorExitNode(monitorObject, monitorId, null));
            monitorExit.setStateAfter(kit.getFrameState().create(kit.bci(), monitorExit));
        }

        if (javaReturnType.getJavaKind().isObject()) {
            returnValue = kit.unboxHandle(returnValue); // before destroying handles in epilogue
        }
        kit.nativeCallEpilogue(handleFrame);
        kit.rethrowPendingException();
        if (javaReturnType.getJavaKind().isObject()) {
            // Just before return to always run the epilogue and never suppress a pending exception
            returnValue = castObject(kit, returnValue, (ResolvedJavaType) javaReturnType);
        }
        kit.createReturn(returnValue, javaReturnType.getJavaKind());

        return kit.finalizeGraph();
    }

    private static ValueNode castObject(JNIGraphKit kit, ValueNode object, ResolvedJavaType type) {
        ValueNode casted = object;
        if (!type.isJavaLangObject()) { // safe cast to expected type
            TypeReference typeRef = TypeReference.createTrusted(kit.getAssumptions(), type);
            LogicNode condition = kit.append(InstanceOfNode.createAllowNull(typeRef, object, null, null));
            if (!condition.isTautology()) {
                ObjectStamp stamp = StampFactory.object(typeRef, false);
                FixedGuardNode fixedGuard = kit.append(new FixedGuardNode(condition, DeoptimizationReason.ClassCastException, DeoptimizationAction.None, false));
                casted = kit.append(PiNode.create(object, stamp, fixedGuard));
            }
        }
        return casted;
    }
}