jack/src/com/android/jack/frontend/VirtualMethodsMarker.java

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * 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.android.jack.frontend;

import com.android.jack.Jack;
import com.android.jack.ir.ast.JClass;
import com.android.jack.ir.ast.JClassOrInterface;
import com.android.jack.ir.ast.JDefinedClass;
import com.android.jack.ir.ast.JDefinedClassOrInterface;
import com.android.jack.ir.ast.JDefinedInterface;
import com.android.jack.ir.ast.JMethodIdWide;
import com.android.jack.ir.ast.JPhantomClassOrInterface;
import com.android.jack.ir.ast.JSession;
import com.android.jack.ir.ast.JType;
import com.android.jack.ir.ast.JVisitor;
import com.android.jack.lookup.CommonTypes;
import com.android.sched.item.Description;
import com.android.sched.marker.Marker;
import com.android.sched.marker.ValidOn;
import com.android.sched.schedulable.Constraint;
import com.android.sched.schedulable.RunnableSchedulable;
import com.android.sched.schedulable.Transform;

import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import javax.annotation.CheckForNull;
import javax.annotation.Nonnull;

/**
 * Set of virtual methods visible in the marked type. For this set, 2 {@link JMethodIdWide}s are
 * considered equals when their name and argument types are equals.
 */
@Description("Set of virtual methods visible in the marked type.")
@ValidOn({JDefinedClassOrInterface.class, JPhantomClassOrInterface.class})
public class VirtualMethodsMarker implements Marker, Iterable<JMethodIdWide>, Cloneable {

  /**
   * A remover for {@link VirtualMethodsMarker}
   */
  @Description("Removes VirtualMethodsMarker")
  @Transform(remove = VirtualMethodsMarker.class)
  @Constraint(need = VirtualMethodsMarker.class)
  public static class Remover implements RunnableSchedulable<JSession> {
    private static class Visitor extends JVisitor {

      @Nonnull
      private final JClass javaLangObject = Jack.getSession().getPhantomLookup()
      .getClass(CommonTypes.JAVA_LANG_OBJECT);

      private Visitor() {
        super(false /* needLoading */);
      }

      @Override
      public boolean visit(@Nonnull JDefinedClass definedClass) {
        if (definedClass.removeMarker(VirtualMethodsMarker.class) != null) {
          ensureHierarchyVisited(definedClass);
        }
        return false;
      }

      @Override
      public boolean visit(@Nonnull JDefinedInterface defineInterface) {
        if (defineInterface.removeMarker(VirtualMethodsMarker.class) != null) {
          ensureHierarchyVisited(defineInterface);
        }
        return false;
      }

      @Override
      public boolean visit(@Nonnull JPhantomClassOrInterface phantomClassOrInterface) {
        if (phantomClassOrInterface.removeMarker(VirtualMethodsMarker.class) != null) {
          ensureHierarchyVisited(phantomClassOrInterface);
        }
        return false;
      }

      private void ensureHierarchyVisited(@Nonnull JClassOrInterface node) {
        JClass zuper = getSuper(node);
        if (zuper != null) {
          accept(zuper);
        }
        if (node instanceof JDefinedClassOrInterface) {
          for (JClassOrInterface interfaze : ((JDefinedClassOrInterface) node).getImplements()) {
            accept(interfaze);
          }
        }
      }

      @CheckForNull
      private JClass getSuper(@Nonnull JClassOrInterface node) {
        if (node instanceof JDefinedClass) {
          return ((JDefinedClass) node).getSuperClass();
        }
        if (!node.isSameType(javaLangObject)) {
          return javaLangObject;
        } else {
          return null;
        }
      }
    }

    @Override
    public void run(@Nonnull JSession session) {
      new Visitor().accept(session.getTypesToEmit());
    }
  }

  private static class ComparableMethodId {
    private final int hashCode;
    @Nonnull
    private final JMethodIdWide methodId;
    private ComparableMethodId(@Nonnull JMethodIdWide methodId) {
      this.methodId = methodId;
      int code = methodId.getName().hashCode();
      for (JType type : methodId.getParamTypes()) {
        code ^= type.hashCode();
      }
      hashCode = code;
    }

    @Override
    public int hashCode() {
      return hashCode;
    }

    @Override
    public boolean equals(@CheckForNull Object obj) {
      if (obj == this) {
        return true;
      }
      ComparableMethodId other;
      int otherHashCode;
      try {
        other = (ComparableMethodId) obj;
        otherHashCode = other.hashCode;
      } catch (ClassCastException e) {
        return false;
      } catch (NullPointerException e) {
        return false;
      }
      if (hashCode != otherHashCode) {
        return false;
      }
      List<JType> thisParams = methodId.getParamTypes();
      List<JType> otherParams = other.methodId.getParamTypes();

      if (thisParams.size() != otherParams.size()
          || !methodId.getName().equals(other.methodId.getName())) {
        return false;
      }
      Iterator<JType> otherIterator = otherParams.iterator();
      for (JType thisParam : thisParams) {
        if (thisParam != otherIterator.next()) {
          return false;
        }
      }
      return true;
    }
  }

  @Nonnull
  private HashMap<ComparableMethodId, ComparableMethodId> virtualMethods;

  public VirtualMethodsMarker() {
    virtualMethods =
        new HashMap<ComparableMethodId, ComparableMethodId>();
  }

  @SuppressWarnings("unchecked")
  @Nonnull
  @Override
  public VirtualMethodsMarker clone() {
    VirtualMethodsMarker clone;
    try {
      clone = (VirtualMethodsMarker) super.clone();
      clone.virtualMethods =
          (HashMap<ComparableMethodId, ComparableMethodId>) virtualMethods.clone();
      return clone;
    } catch (CloneNotSupportedException e) {
      throw new AssertionError();
    }
  }

  @Nonnull
  @Override
  public Marker cloneIfNeeded() {
    return this;
  }

  public void add(@Nonnull JMethodIdWide method) {
    ComparableMethodId comparable = new ComparableMethodId(method);
    virtualMethods.put(comparable, comparable);
  }

  @CheckForNull
  public JMethodIdWide get(@Nonnull JMethodIdWide method) {
    ComparableMethodId searched = new ComparableMethodId(method);
    ComparableMethodId found = virtualMethods.get(searched);
    if (found != null) {
      return found.methodId;
    } else {
      return null;
    }
  }

  @Nonnull
  @Override
  public Iterator<JMethodIdWide> iterator() {
    return new Iterator<JMethodIdWide>() {

      @Nonnull
      private final Iterator<ComparableMethodId> iterator = virtualMethods.values().iterator();

      @Override
      public boolean hasNext() {
        return iterator.hasNext();
      }

      @Nonnull
      @Override
      public JMethodIdWide next() {
        return iterator.next().methodId;
      }

      @Override
      public void remove() {
        throw new UnsupportedOperationException();
      }
    };
  }

}