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/*
* 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 org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.cache;
import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSink;
import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSpec;
import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.cache.Cache.CacheException;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Log;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ReusableBufferedOutputStream;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* Writes data into a cache.
*
* <p>If the {@link DataSpec} passed to {@link #open(DataSpec)} has the {@code length} field set to
* {@link C#LENGTH_UNSET} and {@link DataSpec#FLAG_DONT_CACHE_IF_LENGTH_UNKNOWN} set, then {@link
* #write(byte[], int, int)} calls are ignored.
*/
public final class CacheDataSink implements DataSink {
/** Default {@code fragmentSize} recommended for caching use cases. */
public static final long DEFAULT_FRAGMENT_SIZE = 5 * 1024 * 1024;
/** Default buffer size in bytes. */
public static final int DEFAULT_BUFFER_SIZE = 20 * 1024;
private static final long MIN_RECOMMENDED_FRAGMENT_SIZE = 2 * 1024 * 1024;
private static final String TAG = "CacheDataSink";
private final Cache cache;
private final long fragmentSize;
private final int bufferSize;
private DataSpec dataSpec;
private long dataSpecFragmentSize;
private File file;
private OutputStream outputStream;
private long outputStreamBytesWritten;
private long dataSpecBytesWritten;
private ReusableBufferedOutputStream bufferedOutputStream;
/**
* Thrown when IOException is encountered when writing data into sink.
*/
public static class CacheDataSinkException extends CacheException {
public CacheDataSinkException(IOException cause) {
super(cause);
}
}
/**
* Constructs an instance using {@link #DEFAULT_BUFFER_SIZE}.
*
* @param cache The cache into which data should be written.
* @param fragmentSize For requests that should be fragmented into multiple cache files, this is
* the maximum size of a cache file in bytes. If set to {@link C#LENGTH_UNSET} then no
* fragmentation will occur. Using a small value allows for finer-grained cache eviction
* policies, at the cost of increased overhead both on the cache implementation and the file
* system. Values under {@code (2 * 1024 * 1024)} are not recommended.
*/
public CacheDataSink(Cache cache, long fragmentSize) {
this(cache, fragmentSize, DEFAULT_BUFFER_SIZE);
}
/**
* @param cache The cache into which data should be written.
* @param fragmentSize For requests that should be fragmented into multiple cache files, this is
* the maximum size of a cache file in bytes. If set to {@link C#LENGTH_UNSET} then no
* fragmentation will occur. Using a small value allows for finer-grained cache eviction
* policies, at the cost of increased overhead both on the cache implementation and the file
* system. Values under {@code (2 * 1024 * 1024)} are not recommended.
* @param bufferSize The buffer size in bytes for writing to a cache file. A zero or negative
* value disables buffering.
*/
public CacheDataSink(Cache cache, long fragmentSize, int bufferSize) {
Assertions.checkState(
fragmentSize > 0 || fragmentSize == C.LENGTH_UNSET,
"fragmentSize must be positive or C.LENGTH_UNSET.");
if (fragmentSize != C.LENGTH_UNSET && fragmentSize < MIN_RECOMMENDED_FRAGMENT_SIZE) {
Log.w(
TAG,
"fragmentSize is below the minimum recommended value of "
+ MIN_RECOMMENDED_FRAGMENT_SIZE
+ ". This may cause poor cache performance.");
}
this.cache = Assertions.checkNotNull(cache);
this.fragmentSize = fragmentSize == C.LENGTH_UNSET ? Long.MAX_VALUE : fragmentSize;
this.bufferSize = bufferSize;
}
@Override
public void open(DataSpec dataSpec) throws CacheDataSinkException {
if (dataSpec.length == C.LENGTH_UNSET
&& dataSpec.isFlagSet(DataSpec.FLAG_DONT_CACHE_IF_LENGTH_UNKNOWN)) {
this.dataSpec = null;
return;
}
this.dataSpec = dataSpec;
this.dataSpecFragmentSize =
dataSpec.isFlagSet(DataSpec.FLAG_ALLOW_CACHE_FRAGMENTATION) ? fragmentSize : Long.MAX_VALUE;
dataSpecBytesWritten = 0;
try {
openNextOutputStream();
} catch (IOException e) {
throw new CacheDataSinkException(e);
}
}
@Override
public void write(byte[] buffer, int offset, int length) throws CacheDataSinkException {
if (dataSpec == null) {
return;
}
try {
int bytesWritten = 0;
while (bytesWritten < length) {
if (outputStreamBytesWritten == dataSpecFragmentSize) {
closeCurrentOutputStream();
openNextOutputStream();
}
int bytesToWrite =
(int) Math.min(length - bytesWritten, dataSpecFragmentSize - outputStreamBytesWritten);
outputStream.write(buffer, offset + bytesWritten, bytesToWrite);
bytesWritten += bytesToWrite;
outputStreamBytesWritten += bytesToWrite;
dataSpecBytesWritten += bytesToWrite;
}
} catch (IOException e) {
throw new CacheDataSinkException(e);
}
}
@Override
public void close() throws CacheDataSinkException {
if (dataSpec == null) {
return;
}
try {
closeCurrentOutputStream();
} catch (IOException e) {
throw new CacheDataSinkException(e);
}
}
private void openNextOutputStream() throws IOException {
long length =
dataSpec.length == C.LENGTH_UNSET
? C.LENGTH_UNSET
: Math.min(dataSpec.length - dataSpecBytesWritten, dataSpecFragmentSize);
file =
cache.startFile(
dataSpec.key, dataSpec.absoluteStreamPosition + dataSpecBytesWritten, length);
FileOutputStream underlyingFileOutputStream = new FileOutputStream(file);
if (bufferSize > 0) {
if (bufferedOutputStream == null) {
bufferedOutputStream = new ReusableBufferedOutputStream(underlyingFileOutputStream,
bufferSize);
} else {
bufferedOutputStream.reset(underlyingFileOutputStream);
}
outputStream = bufferedOutputStream;
} else {
outputStream = underlyingFileOutputStream;
}
outputStreamBytesWritten = 0;
}
private void closeCurrentOutputStream() throws IOException {
if (outputStream == null) {
return;
}
boolean success = false;
try {
outputStream.flush();
success = true;
} finally {
Util.closeQuietly(outputStream);
outputStream = null;
File fileToCommit = file;
file = null;
if (success) {
cache.commitFile(fileToCommit, outputStreamBytesWritten);
} else {
fileToCommit.delete();
}
}
}
}
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