Java Guards类代码示例

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
private MethodHandle getGuard(final ValidationType validationType, final MethodType methodType) {
    switch(validationType) {
        case EXACT_CLASS: {
            return getClassGuard(methodType);
        }
        case INSTANCE_OF: {
            return getAssignableGuard(methodType);
        }
        case IS_ARRAY: {
            return Guards.isArray(0, methodType);
        }
        case NONE: {
            return null;
        }
        default: {
            throw new AssertionError();
        }
    }
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
private MethodHandle getGuard(ValidationType validationType, MethodType methodType) {
    switch(validationType) {
        case EXACT_CLASS: {
            return getClassGuard(methodType);
        }
        case INSTANCE_OF: {
            return getAssignableGuard(methodType);
        }
        case IS_ARRAY: {
            return Guards.isArray(0, methodType);
        }
        case NONE: {
            return null;
        }
        default: {
            throw new AssertionError();
        }
    }
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
@Override
public GuardedInvocation getGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) {
    final Object receiver = linkRequest.getReceiver();
    if(!(receiver instanceof DynamicMethod)) {
        return null;
    }
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if(desc.getNameTokenCount() != 2 && desc.getNameToken(CallSiteDescriptor.SCHEME) != "dyn") {
        return null;
    }
    final String operator = desc.getNameToken(CallSiteDescriptor.OPERATOR);
    if(operator == "call") {
        final MethodHandle invocation = ((DynamicMethod)receiver).getInvocation(
                CallSiteDescriptorFactory.dropParameterTypes(desc, 0, 1), linkerServices);
        if(invocation == null) {
            return null;
        }
        return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,
                desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));
    }
    return null;
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final Object self = linkRequest.getReceiver();
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if (self instanceof ConsString) {
        // In order to treat ConsString like a java.lang.String we need a link request with a string receiver.
        final Object[] arguments = linkRequest.getArguments();
        arguments[0] = "";
        final LinkRequest forgedLinkRequest = linkRequest.replaceArguments(desc, arguments);
        final GuardedInvocation invocation = getGuardedInvocation(beansLinker, forgedLinkRequest, linkerServices);
        // If an invocation is found we add a filter that makes it work for both Strings and ConsStrings.
        return invocation == null ? null : invocation.filterArguments(0, FILTER_CONSSTRING);
    }

    if (self != null && "call".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        // Support dyn:call on any object that supports some @FunctionalInterface
        // annotated interface. This way Java method, constructor references or
        // implementations of java.util.function.* interfaces can be called as though
        // those are script functions.
        final Method m = getFunctionalInterfaceMethod(self.getClass());
        if (m != null) {
            final MethodType callType = desc.getMethodType();
            // 'callee' and 'thiz' passed from script + actual arguments
            if (callType.parameterCount() != m.getParameterCount() + 2) {
                throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
            }
            return new GuardedInvocation(
                    // drop 'thiz' passed from the script.
                    MH.dropArguments(desc.getLookup().unreflect(m), 1, callType.parameterType(1)),
                    Guards.getInstanceOfGuard(m.getDeclaringClass())).asTypeSafeReturn(
                            new NashornBeansLinkerServices(linkerServices), callType);
        }
    }
    return getGuardedInvocation(beansLinker, linkRequest, linkerServices);
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();

    Bootstrap.checkReflectionAccess(receiverClass, true);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        if (! Modifier.isPublic(receiverClass.getModifiers())) {
            throw ECMAErrors.typeError("new.on.nonpublic.javatype", receiverClass.getName());
        }

        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass);

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null,
                    linkRequest.getCallSiteDescriptor().getLookup());
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
boolean isVisibleFrom(final ClassLoader classLoader) {
    for(int i = 0; i < classes.length; ++i) {
        if(!Guards.canReferenceDirectly(classLoader, classes[i].getClassLoader())) {
            return false;
        }
    }
    return true;
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
BeanLinker(final Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    } else if(List.class.isAssignableFrom(clazz)) {
        setPropertyGetter("length", GET_COLLECTION_LENGTH, ValidationType.INSTANCE_OF);
    }
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
private GuardedInvocationComponent getLengthGetter(final CallSiteDescriptor callSiteDescriptor) {
    assertParameterCount(callSiteDescriptor, 1);
    final MethodType callSiteType = callSiteDescriptor.getMethodType();
    final Class<?> declaredType = callSiteType.parameterType(0);
    // If declared type of receiver at the call site is already an array, collection, or map, bind without guard.
    // Thing is, it'd be quite stupid of a call site creator to go though invokedynamic when it knows in advance
    // they're dealing with an array, collection, or map, but hey...
    if(declaredType.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType));
    } else if(Collection.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType));
    } else if(Map.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType));
    }

    // Otherwise, create a binding based on the actual type of the argument with an appropriate guard.
    if(clazz.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType), Guards.isArray(0,
                callSiteType), ValidationType.IS_ARRAY);
    } if(Collection.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType), Guards.asType(
                COLLECTION_GUARD, callSiteType), Collection.class, ValidationType.INSTANCE_OF);
    } if(Map.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType), Guards.asType(MAP_GUARD,
                callSiteType), Map.class, ValidationType.INSTANCE_OF);
    }
    // Can't retrieve length for objects that are neither arrays, nor collections, nor maps.
    return null;
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) {
    final Object receiver = linkRequest.getReceiver();
    if(!(receiver instanceof DynamicMethod)) {
        return null;
    }
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if(desc.getNameTokenCount() != 2 && desc.getNameToken(CallSiteDescriptor.SCHEME) != "dyn") {
        return null;
    }
    final String operator = desc.getNameToken(CallSiteDescriptor.OPERATOR);
    final DynamicMethod dynMethod = (DynamicMethod)receiver;
    final boolean constructor = dynMethod.isConstructor();
    final MethodHandle invocation;

    if (operator == "call" && !constructor) {
        invocation = dynMethod.getInvocation(
                CallSiteDescriptorFactory.dropParameterTypes(desc, 0, 1), linkerServices);
    } else if (operator == "new" && constructor) {
        final MethodHandle ctorInvocation = dynMethod.getInvocation(desc, linkerServices);
        if(ctorInvocation == null) {
            return null;
        }

        // Insert null for StaticClass parameter
        invocation = MethodHandles.insertArguments(ctorInvocation, 0, (Object)null);
    } else {
        return null;
    }

    if (invocation != null) {
        return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,
            desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));
    }

    return null;
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final Object self = linkRequest.getReceiver();
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if (self instanceof ConsString) {
        // In order to treat ConsString like a java.lang.String we need a link request with a string receiver.
        final Object[] arguments = linkRequest.getArguments();
        arguments[0] = "";
        final LinkRequest forgedLinkRequest = linkRequest.replaceArguments(desc, arguments);
        final GuardedInvocation invocation = getGuardedInvocation(beansLinker, forgedLinkRequest, linkerServices);
        // If an invocation is found we add a filter that makes it work for both Strings and ConsStrings.
        return invocation == null ? null : invocation.filterArguments(0, FILTER_CONSSTRING);
    }

    if (self != null && "call".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        // Support dyn:call on any object that supports some @FunctionalInterface
        // annotated interface. This way Java method, constructor references or
        // implementations of java.util.function.* interfaces can be called as though
        // those are script functions.
        final Method m = getFunctionalInterfaceMethod(self.getClass());
        if (m != null) {
            final MethodType callType = desc.getMethodType();
            // 'callee' and 'thiz' passed from script + actual arguments
            if (callType.parameterCount() != m.getParameterCount() + 2) {
                throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
            }
            return new GuardedInvocation(
                    // drop 'thiz' passed from the script.
                    MH.dropArguments(linkerServices.filterInternalObjects(desc.getLookup().unreflect(m)), 1,
                            callType.parameterType(1)), Guards.getInstanceOfGuard(
                                    m.getDeclaringClass())).asTypeSafeReturn(
                                            new NashornBeansLinkerServices(linkerServices), callType);
        }
    }
    return getGuardedInvocation(beansLinker, linkRequest, linkerServices);
}
 

import jdk.internal.dynalink.support.Guards; //导入依赖的package包/类
@Override
public GuardedInvocation getGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();
    Bootstrap.checkReflectionAccess(receiverClass, true);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass);

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null,
                    linkRequest.getCallSiteDescriptor().getLookup());
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}