content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.spark.unsafe.memory;
  
  public interface MemoryAllocator {
  
    /**
     * Whether to fill newly allocated and deallocated memory with 0xa5 and 0x5a bytes respectively.
     * This helps catch misuse of uninitialized or freed memory, but imposes some overhead.
     */
    boolean MEMORY_DEBUG_FILL_ENABLED = Boolean.parseBoolean(
      System.getProperty("spark.memory.debugFill", "false"));
  
    // Same as jemalloc's debug fill values.
    byte MEMORY_DEBUG_FILL_CLEAN_VALUE = (byte)0xa5;
    byte MEMORY_DEBUG_FILL_FREED_VALUE = (byte)0x5a;
  
    /**
     * Allocates a contiguous block of memory. Note that the allocated memory is not guaranteed
     * to be zeroed out (call `fill(0)` on the result if this is necessary).
     */
    MemoryBlock allocate(long size) throws OutOfMemoryError;
  
    void free(MemoryBlock memory);
  
    MemoryAllocator UNSAFE = new UnsafeMemoryAllocator();
  
    MemoryAllocator HEAP = new HeapMemoryAllocator();
  }
  