diff options
Diffstat (limited to 'src/org/chromium/support_lib_boundary/BoundaryInterfaceReflectionUtil.java')
-rw-r--r-- | src/org/chromium/support_lib_boundary/BoundaryInterfaceReflectionUtil.java | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/src/org/chromium/support_lib_boundary/BoundaryInterfaceReflectionUtil.java b/src/org/chromium/support_lib_boundary/BoundaryInterfaceReflectionUtil.java new file mode 100644 index 0000000..caf7277 --- /dev/null +++ b/src/org/chromium/support_lib_boundary/BoundaryInterfaceReflectionUtil.java @@ -0,0 +1,70 @@ +// Copyright 2018 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. +package org.chromium.support_lib_boundary; + +import android.annotation.TargetApi; +import android.os.Build; + +import java.lang.reflect.InvocationHandler; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.lang.reflect.Proxy; + +/** + * A set of utility methods used for calling across the support library boundary. + */ +public class BoundaryInterfaceReflectionUtil { + /** + * Utility method for fetching a method from the current classloader, with the same signature + * (package + class + method name + parameters) as a given method defined in another + * classloader. + */ + public static Method dupeMethod(Method method) + throws ClassNotFoundException, NoSuchMethodException { + Class<?> declaringClass = Class.forName(method.getDeclaringClass().getName()); + Class[] otherSideParameterClasses = method.getParameterTypes(); + Class[] parameterClasses = new Class[otherSideParameterClasses.length]; + for (int n = 0; n < parameterClasses.length; n++) { + Class<?> clazz = otherSideParameterClasses[n]; + // Primitive classes are shared between the classloaders - so we can use the same + // primitive class declarations on either side. Non-primitive classes must be looked up + // by name. + parameterClasses[n] = clazz.isPrimitive() ? clazz : Class.forName(clazz.getName()); + } + return declaringClass.getDeclaredMethod(method.getName(), parameterClasses); + } + + /** + * Returns an implementation of the boundary interface named clazz, by delegating method calls + * to the {@link InvocationHandler} invocationHandler. + */ + public static <T> T castToSuppLibClass(Class<T> clazz, InvocationHandler invocationHandler) { + return clazz.cast( + Proxy.newProxyInstance(BoundaryInterfaceReflectionUtil.class.getClassLoader(), + new Class[] {clazz}, invocationHandler)); + } + + /** + * Create an {@link java.lang.reflect.InvocationHandler} that delegates method calls to + * {@param delegate}, making sure that the {@link java.lang.reflect.Method} and parameters being + * passed to {@param delegate} exist in the same {@link java.lang.ClassLoader} as {@param + * delegate}. + */ + @TargetApi(Build.VERSION_CODES.KITKAT) + public static InvocationHandler createInvocationHandlerFor(final Object delegate) { + return new InvocationHandler() { + @Override + public Object invoke(Object o, Method method, Object[] objects) throws Throwable { + try { + return dupeMethod(method).invoke(delegate, objects); + } catch (InvocationTargetException e) { + // If something went wrong, ensure we throw the original exception. + throw e.getTargetException(); + } catch (ReflectiveOperationException e) { + throw new RuntimeException("Reflection failed for method " + method, e); + } + } + }; + } +} |