content: /*
   * Copyright (C) 2016 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.apksig.internal.util;
  
  import com.android.apksig.util.DataSink;
  import java.io.IOException;
  import java.io.RandomAccessFile;
  import java.nio.ByteBuffer;
  import java.nio.channels.FileChannel;
  
  /**
   * {@link DataSink} which outputs received data into the associated file, sequentially.
   */
  public class RandomAccessFileDataSink implements DataSink {
  
      private final RandomAccessFile mFile;
      private final FileChannel mFileChannel;
      private long mPosition;
  
      /**
       * Constructs a new {@code RandomAccessFileDataSink} which stores output starting from the
       * beginning of the provided file.
       */
      public RandomAccessFileDataSink(RandomAccessFile file) {
          this(file, 0);
      }
  
      /**
       * Constructs a new {@code RandomAccessFileDataSink} which stores output starting from the
       * specified position of the provided file.
       */
      public RandomAccessFileDataSink(RandomAccessFile file, long startPosition) {
          if (file == null) {
              throw new NullPointerException("file == null");
          }
          if (startPosition < 0) {
              throw new IllegalArgumentException("startPosition: " + startPosition);
          }
          mFile = file;
          mFileChannel = file.getChannel();
          mPosition = startPosition;
      }
  
      /**
       * Returns the underlying {@link RandomAccessFile}.
       */
      public RandomAccessFile getFile() {
          return mFile;
      }
  
      @Override
      public void consume(byte[] buf, int offset, int length) throws IOException {
          if (offset < 0) {
              // Must perform this check here because RandomAccessFile.write doesn't throw when offset
              // is negative but length is 0
              throw new IndexOutOfBoundsException("offset: " + offset);
          }
          if (offset > buf.length) {
              // Must perform this check here because RandomAccessFile.write doesn't throw when offset
              // is too large but length is 0
              throw new IndexOutOfBoundsException(
                      "offset: " + offset + ", buf.length: " + buf.length);
          }
          if (length == 0) {
              return;
          }
  
          synchronized (mFile) {
              mFile.seek(mPosition);
              mFile.write(buf, offset, length);
              mPosition += length;
          }
      }
  
      @Override
      public void consume(ByteBuffer buf) throws IOException {
          int length = buf.remaining();
          if (length == 0) {
              return;
          }
  
          synchronized (mFile) {
              mFile.seek(mPosition);
              while (buf.hasRemaining()) {
                  mFileChannel.write(buf);
              }
              mPosition += length;
          }
      }
  }
  