runtime/jobject_comparator.cc

/*
 * Copyright (C) 2012 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.
 */

#include "jobject_comparator.h"

#include "mirror/array-inl.h"
#include "mirror/class-inl.h"
#include "mirror/object-inl.h"
#include "scoped_thread_state_change.h"

namespace art {

bool JobjectComparator::operator()(jobject jobj1, jobject jobj2) const {
  // Ensure null references and cleared jweaks appear at the end.
  if (jobj1 == NULL) {
    return true;
  } else if (jobj2 == NULL) {
    return false;
  }
  ScopedObjectAccess soa(Thread::Current());
  mirror::Object* obj1 = soa.Decode<mirror::Object*>(jobj1);
  mirror::Object* obj2 = soa.Decode<mirror::Object*>(jobj2);
  if (obj1 == NULL) {
    return true;
  } else if (obj2 == NULL) {
    return false;
  }
  // Sort by class...
  if (obj1->GetClass() != obj2->GetClass()) {
    return obj1->GetClass()->IdentityHashCode() < obj2->IdentityHashCode();
  } else {
    // ...then by size...
    size_t count1 = obj1->SizeOf();
    size_t count2 = obj2->SizeOf();
    if (count1 != count2) {
      return count1 < count2;
    } else {
      // ...and finally by identity hash code.
      return obj1->IdentityHashCode() < obj2->IdentityHashCode();
    }
  }
}

}  // namespace art