/*
* Copyright (C) 2016 Square, Inc.
*
* 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 okhttp3.internal.cache2;
import java.io.
EOFException;
import java.io.
IOException;
import java.nio.channels.
FileChannel;
import okio.
Buffer;
import okio.
Okio;
/**
* Read and write a target file. Unlike Okio's built-in {@linkplain Okio#source(java.io.File) file
* source} and {@linkplain Okio#sink(java.io.File) file sink} this class offers:
*
* <ul>
* <li><strong>Read/write:</strong> read and write using the same operator.
* <li><strong>Random access:</strong> access any position within the file.
* <li><strong>Shared channels:</strong> read and write a file channel that's shared between
* multiple operators. Note that although the underlying {@code FileChannel} may be shared,
* each {@code FileOperator} should not be.
* </ul>
*/
final class
FileOperator {
private final
FileChannel fileChannel;
FileOperator(
FileChannel fileChannel) {
this.
fileChannel =
fileChannel;
}
/** Write {@code byteCount} bytes from {@code source} to the file at {@code pos}. */
public void
write(long
pos,
Buffer source, long
byteCount) throws
IOException {
if (
byteCount < 0 ||
byteCount >
source.
size()) throw new
IndexOutOfBoundsException();
while (
byteCount > 0L) {
long
bytesWritten =
fileChannel.
transferFrom(
source,
pos,
byteCount);
pos +=
bytesWritten;
byteCount -=
bytesWritten;
}
}
/**
* Copy {@code byteCount} bytes from the file at {@code pos} into to {@code source}. It is the
* caller's responsibility to make sure there are sufficient bytes to read: if there aren't this
* method throws an {@link EOFException}.
*/
public void
read(long
pos,
Buffer sink, long
byteCount) throws
IOException {
if (
byteCount < 0) throw new
IndexOutOfBoundsException();
while (
byteCount > 0L) {
long
bytesRead =
fileChannel.
transferTo(
pos,
byteCount,
sink);
pos +=
bytesRead;
byteCount -=
bytesRead;
}
}
}