content: /*
   * Copyright (C) 2015 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.ahat.heapdump;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * Provides Comparators and helper functions for sorting Instances, Sites, and
   * other things.
   *
   * Note: The Comparators defined here impose orderings that are inconsistent
   * with equals. They should not be used for element lookup or search. They
   * should only be used for showing elements to the user in different orders.
   */
  public class Sort {
    /**
     * Compare instances by their total retained size.
     * Different instances with the same total retained size are considered
     * equal for the purposes of comparison.
     * This sorts instances from larger retained size to smaller retained size.
     */
    public static final Comparator<AhatInstance> INSTANCE_BY_TOTAL_RETAINED_SIZE
      = new Comparator<AhatInstance>() {
      @Override
      public int compare(AhatInstance a, AhatInstance b) {
        return Long.compare(b.getTotalRetainedSize(), a.getTotalRetainedSize());
      }
    };
  
    /**
     * Compare instances by their retained size for a given heap index.
     * Different instances with the same total retained size are considered
     * equal for the purposes of comparison.
     * This sorts instances from larger retained size to smaller retained size.
     */
    public static class InstanceByHeapRetainedSize implements Comparator<AhatInstance> {
      private AhatHeap mHeap;
  
      public InstanceByHeapRetainedSize(AhatHeap heap) {
        mHeap = heap;
      }
  
      @Override
      public int compare(AhatInstance a, AhatInstance b) {
        return Long.compare(b.getRetainedSize(mHeap), a.getRetainedSize(mHeap));
      }
    }
  
    /**
     * Compare objects based on a list of comparators, giving priority to the
     * earlier comparators in the list.
     */
    public static class WithPriority<T> implements Comparator<T> {
      private List<Comparator<T>> mComparators;
  
      public WithPriority(Comparator<T>... comparators) {
        mComparators = Arrays.asList(comparators);
      }
  
      public WithPriority(List<Comparator<T>> comparators) {
        mComparators = comparators;
      }
  
      @Override
      public int compare(T a, T b) {
        int res = 0;
        Iterator<Comparator<T>> iter = mComparators.iterator();
        while (res == 0 && iter.hasNext()) {
          res = iter.next().compare(a, b);
        }
        return res;
      }
    }
  
    public static Comparator<AhatInstance> defaultInstanceCompare(AhatSnapshot snapshot) {
      List<Comparator<AhatInstance>> comparators = new ArrayList<Comparator<AhatInstance>>();
  
      // Priority goes to the app heap, if we can find one.
      AhatHeap appHeap = snapshot.getHeap("app");
      if (appHeap != null) {
        comparators.add(new InstanceByHeapRetainedSize(appHeap));
      }
  
      // Next is by total retained size.
      comparators.add(INSTANCE_BY_TOTAL_RETAINED_SIZE);
      return new WithPriority<AhatInstance>(comparators);
    }
  
    /**
     * Compare Sites by the size of objects allocated on a given heap.
     * Different object infos with the same size on the given heap are
     * considered equal for the purposes of comparison.
     * This sorts sites from larger size to smaller size.
     */
    public static class SiteByHeapSize implements Comparator<Site> {
      AhatHeap mHeap;
  
      public SiteByHeapSize(AhatHeap heap) {
        mHeap = heap;
      }
  
      @Override
      public int compare(Site a, Site b) {
        return Long.compare(b.getSize(mHeap), a.getSize(mHeap));
      }
    }
  
    /**
     * Compare Sites by the total size of objects allocated.
     * This sorts sites from larger size to smaller size.
     */
    public static final Comparator<Site> SITE_BY_TOTAL_SIZE = new Comparator<Site>() {
      @Override
      public int compare(Site a, Site b) {
        return Long.compare(b.getTotalSize(), a.getTotalSize());
      }
    };
  
    public static Comparator<Site> defaultSiteCompare(AhatSnapshot snapshot) {
      List<Comparator<Site>> comparators = new ArrayList<Comparator<Site>>();
  
      // Priority goes to the app heap, if we can find one.
      AhatHeap appHeap = snapshot.getHeap("app");
      if (appHeap != null) {
        comparators.add(new SiteByHeapSize(appHeap));
      }
  
      // Next is by total size.
      comparators.add(SITE_BY_TOTAL_SIZE);
      return new WithPriority<Site>(comparators);
    }
  
    /**
     * Compare Site.ObjectsInfo by their size.
     * Different object infos with the same total retained size are considered
     * equal for the purposes of comparison.
     * This sorts object infos from larger retained size to smaller size.
     */
    public static final Comparator<Site.ObjectsInfo> OBJECTS_INFO_BY_SIZE
      = new Comparator<Site.ObjectsInfo>() {
      @Override
      public int compare(Site.ObjectsInfo a, Site.ObjectsInfo b) {
        return Long.compare(b.numBytes, a.numBytes);
      }
    };
  
    /**
     * Compare Site.ObjectsInfo by heap name.
     * Different object infos with the same heap name are considered equal for
     * the purposes of comparison.
     */
    public static final Comparator<Site.ObjectsInfo> OBJECTS_INFO_BY_HEAP_NAME
      = new Comparator<Site.ObjectsInfo>() {
      @Override
      public int compare(Site.ObjectsInfo a, Site.ObjectsInfo b) {
        return a.heap.getName().compareTo(b.heap.getName());
      }
    };
  
    /**
     * Compare Site.ObjectsInfo by class name.
     * Different object infos with the same class name are considered equal for
     * the purposes of comparison.
     */
    public static final Comparator<Site.ObjectsInfo> OBJECTS_INFO_BY_CLASS_NAME
      = new Comparator<Site.ObjectsInfo>() {
      @Override
      public int compare(Site.ObjectsInfo a, Site.ObjectsInfo b) {
        String aName = a.getClassName();
        String bName = b.getClassName();
        return aName.compareTo(bName);
      }
    };
  }
  
  