drm/java/android/drm/DrmOutputStream.java

/*
 * Copyright (C) 2012 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 android.drm;

import static android.drm.DrmConvertedStatus.STATUS_OK;

import java.io.File;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.net.UnknownServiceException;
import java.util.Arrays;

import libcore.io.IoUtils;
import libcore.util.SneakyThrow;

/**
 * Stream that applies a {@link DrmManagerClient} transformation to data before
 * writing to disk, similar to a {@link FilterOutputStream}.
 *
 * @hide
 */
public class DrmOutputStream extends OutputStream {

    private final DrmManagerClient mClient;

    private int mSessionId;
    private RandomAccessFile mOutput;

    public DrmOutputStream(DrmManagerClient client, File file, String mimeType) throws IOException {
        mClient = client;
        mOutput = new RandomAccessFile(file, "rw");

        try {
            mSessionId = mClient.openConvertSession(mimeType);
            if (mSessionId == DrmManagerClient.INVALID_SESSION) {
                throw new UnknownServiceException("Failed to open DRM session for " + mimeType);
            }
        } catch (Throwable thrown) {
            IoUtils.closeQuietly(mOutput);
            SneakyThrow.sneakyThrow(thrown);
        }
    }

    @Override
    public void close() throws IOException {
        try {
            final DrmConvertedStatus status = mClient.closeConvertSession(mSessionId);
            if (status.statusCode == STATUS_OK) {
                mOutput.seek(status.offset);
                mOutput.write(status.convertedData);
            } else {
                throw new IOException("Unexpected DRM status: " + status.statusCode);
            }
        } finally {
            try {
                mOutput.getFD().sync();
            } finally {
                mOutput.close();
                mOutput = null;
            }
        }
    }

    @Override
    public void write(byte[] buffer, int offset, int count) throws IOException {
        Arrays.checkOffsetAndCount(buffer.length, offset, count);

        final byte[] exactBuffer;
        if (count == buffer.length) {
            exactBuffer = buffer;
        } else {
            exactBuffer = new byte[count];
            System.arraycopy(buffer, offset, exactBuffer, 0, count);
        }

        final DrmConvertedStatus status = mClient.convertData(mSessionId, exactBuffer);
        if (status.statusCode == STATUS_OK) {
            mOutput.write(status.convertedData);
        } else {
            throw new IOException("Unexpected DRM status: " + status.statusCode);
        }
    }

    @Override
    public void write(int oneByte) throws IOException {
        write(new byte[] { (byte) oneByte });
    }
}