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// Copyright 2016 Google Inc. All rights reserved.
//
// 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.google.archivepatcher.generator.bsdiff;
import com.google.archivepatcher.generator.bsdiff.RandomAccessObject.RandomAccessByteArrayObject;
import com.google.archivepatcher.generator.bsdiff.RandomAccessObject.RandomAccessFileObject;
import com.google.archivepatcher.generator.bsdiff.RandomAccessObject.RandomAccessMmapObject;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
/**
* A factory for creating instances of {@link RandomAccessObject}. BsDiff needs to store some
* ancillary data of size proportional to the binary to be patched. This allows abstraction of the
* allocation so that BsDiff can run either entirely in-memory (faster) or with file-backed swap
* (handles bigger inputs without consuming inordinate amounts of memory).
*/
public interface RandomAccessObjectFactory {
public RandomAccessObject create(int size) throws IOException;
/**
* A factory that produces {@link RandomAccessFileObject} instances backed by temp files.
*/
// TODO(hartmanng): rethink the handling of these temp files. It's confusing and shouldn't
// really be the responsibility of RandomAccessObject.
public static final class RandomAccessFileObjectFactory implements RandomAccessObjectFactory {
private static final String FILE_NAME_PREFIX = "wavsprafof";
private final String mMode;
/**
* Factory for a RandomAccessFileObject.
* @param mode the file mode string ("r", "w", "rw", etc - see documentation for
* {@link RandomAccessFile})
*/
public RandomAccessFileObjectFactory(String mode) {
mMode = mode;
}
/**
* Creates a temp file, and returns a {@link RandomAccessFile} wrapped in a
* {@link RandomAccessFileObject} representing the new temp file. The temp file does not need to
* explicitly be managed (deleted) by the caller, as long as the caller ensures
* {@link RandomAccessObject#close()} is called when the object is no longer needed.
*/
// TODO(hartmanng): rethink the handling of these temp files. It's confusing and shouldn't
// really be the responsibility of RandomAccessObject.
@Override
public RandomAccessObject create(int size) throws IOException {
return new RandomAccessObject.RandomAccessFileObject(
File.createTempFile(FILE_NAME_PREFIX, "temp"), mMode, true);
}
}
/**
* A factory that produces {@link RandomAccessByteArrayObject} instances backed by memory.
*/
public static final class RandomAccessByteArrayObjectFactory
implements RandomAccessObjectFactory {
@Override
public RandomAccessObject create(int size) {
return new RandomAccessObject.RandomAccessByteArrayObject(size);
}
}
/**
* A factory that produces {@link RandomAccessMmapObject} instances backed by temp files..
*/
// TODO(hartmanng): rethink the handling of these temp files. It's confusing and shouldn't
// really be the responsibility of RandomAccessObject.
public static final class RandomAccessMmapObjectFactory implements RandomAccessObjectFactory {
private static final String FILE_NAME_PREFIX = "wavsprafof";
private String mMode;
/**
* Factory for a RandomAccessMmapObject.
* @param mode the file mode string ("r", "w", "rw", etc - see documentation for
* {@link RandomAccessFile})
*/
public RandomAccessMmapObjectFactory(String mode) {
mMode = mode;
}
/**
* Creates a temp file, and returns a {@link RandomAccessFile} wrapped in a
* {@link RandomAccessMmapObject} representing the new temp file. The temp file does not need to
* explicitly be managed (deleted) by the caller, as long as the caller ensures
* {@link RandomAccessObject#close()} is called when the object is no longer needed.
*/
// TODO(hartmanng): rethink the handling of these temp files. It's confusing and shouldn't
// really be the responsibility of RandomAccessObject.
@Override
public RandomAccessObject create(int size) throws IOException {
return new RandomAccessObject.RandomAccessMmapObject(FILE_NAME_PREFIX, mMode, size);
}
}
}
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