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/*
 * Copyright (C) 2006 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.internal;

import com.google.common.collect.ImmutableMap;
import com.google.inject.spi.InjectionPoint;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.List;
import java.util.function.BiFunction;
import org.aopalliance.intercept.MethodInterceptor;

/**
 * Produces construction proxies that invoke the class constructor.
 *
 * @author [email protected] (Bob Lee)
 */
final class DefaultConstructionProxyFactory implements ConstructionProxyFactory {

  private final InjectionPoint injectionPoint;

  /** @param injectionPoint an injection point whose member is a constructor of {@code T}. */
  DefaultConstructionProxyFactory(InjectionPoint injectionPoint) {
    this.injectionPoint = injectionPoint;
  }

  @Override
  public ConstructionProxy create() {
    @SuppressWarnings("unchecked") // the injection point is for a constructor of T
    final Constructor constructor = (Constructor) injectionPoint.getMember();

    if (InternalFlags.isBytecodeGenEnabled()) {
      try {
        BiFunction fastConstructor =
            BytecodeGen.fastConstructor(constructor);
        if (fastConstructor != null) {
          return new FastClassProxy(injectionPoint, constructor, fastConstructor);
        }
      } catch (Exception | LinkageError e) {
        /* fall-through */
      }
    }

    return new ReflectiveProxy(injectionPoint, constructor);
  }

  /** A {@link ConstructionProxy} that uses bytecode generation to invoke the constructor. */
  private static final class FastClassProxy implements ConstructionProxy {
    final InjectionPoint injectionPoint;
    final Constructor constructor;
    final BiFunction fastConstructor;

    FastClassProxy(
        InjectionPoint injectionPoint,
        Constructor constructor,
        BiFunction fastConstructor) {
      this.injectionPoint = injectionPoint;
      this.constructor = constructor;
      this.fastConstructor = fastConstructor;
    }

    @Override
    @SuppressWarnings("unchecked")
    public T newInstance(Object... arguments) throws InvocationTargetException {
      try {
        return (T) fastConstructor.apply(null, arguments);
      } catch (Throwable e) {
        throw new InvocationTargetException(e); // match JDK reflection behaviour
      }
    }

    @Override
    public InjectionPoint getInjectionPoint() {
      return injectionPoint;
    }

    @Override
    public Constructor getConstructor() {
      return constructor;
    }

    @Override
    public ImmutableMap> getMethodInterceptors() {
      return ImmutableMap.of();
    }
  }

  private static final class ReflectiveProxy implements ConstructionProxy {
    final Constructor constructor;
    final InjectionPoint injectionPoint;

    ReflectiveProxy(InjectionPoint injectionPoint, Constructor constructor) {
      if (!Modifier.isPublic(constructor.getDeclaringClass().getModifiers())
          || !Modifier.isPublic(constructor.getModifiers())) {
        constructor.setAccessible(true);
      }
      this.injectionPoint = injectionPoint;
      this.constructor = constructor;
    }

    @Override
    public T newInstance(Object... arguments) throws InvocationTargetException {
      try {
        return constructor.newInstance(arguments);
      } catch (InstantiationException e) {
        throw new AssertionError(e); // shouldn't happen, we know this is a concrete type
      } catch (IllegalAccessException e) {
        throw new AssertionError(e); // a security manager is blocking us, we're hosed
      }
    }

    @Override
    public InjectionPoint getInjectionPoint() {
      return injectionPoint;
    }

    @Override
    public Constructor getConstructor() {
      return constructor;
    }

    @Override
    public ImmutableMap> getMethodInterceptors() {
      return ImmutableMap.of();
    }
  }
}