TraceFileWriter.java

/*
 * Copyright (C) 2011 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.ide.eclipse.gltrace;

import com.android.ide.eclipse.gltrace.GLProtoBuf.GLMessage;
import com.android.ide.eclipse.gltrace.GLProtoBuf.GLMessage.Function;
import com.google.protobuf.InvalidProtocolBufferException;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;

/** A class that streams data received from a socket into the trace file. */
public class TraceFileWriter {
    private DataInputStream mInputStream;
    private DataOutputStream mOutputStream;
    private Thread mReceiverThread;

    private int mFileSize = 0;
    private int mFrameCount = 0;

    /**
     * Construct a trace file writer.
     * @param fos output stream to write trace data to
     * @param is input stream from which trace data is read
     */
    public TraceFileWriter(FileOutputStream fos, DataInputStream is) {
        mOutputStream = new DataOutputStream(fos);
        mInputStream = is;
    }

    public void start() {
        // launch thread
        mReceiverThread = new Thread(new GLTraceReceiverTask());
        mReceiverThread.setName("GL Trace Receiver");
        mReceiverThread.start();
    }

    public void stopTracing() {
        // close socket to stop the receiver thread
        try {
            mInputStream.close();
        } catch (IOException e) {
            // ignore exception while closing socket
        }

        // wait for receiver to complete
        try {
            mReceiverThread.join();
        } catch (InterruptedException e1) {
            // ignore, this cannot be interrupted
        }

        // close stream
        try {
            mOutputStream.close();
        } catch (IOException e) {
            // ignore error while closing stream
        }
    }

    /**
     * The GLTraceReceiverTask collects trace data from the device and writes it
     * into a file while collecting some stats on the way.
     */
    private class GLTraceReceiverTask implements Runnable {
        @Override
        public void run() {
            while (true) {
                byte[] buffer = readTraceData(mInputStream);
                if (buffer == null) {
                    break;
                }

                try {
                    writeTraceData(buffer, mOutputStream);
                } catch (IOException e) {
                    break;
                }

                updateTraceStats(buffer);
            }
        }
    }

    private byte[] readTraceData(DataInputStream dis) {
        int len;
        try {
            len = dis.readInt();
        } catch (IOException e1) {
            return null;
        }
        len = Integer.reverseBytes(len);    // readInt is big endian, we want little endian

        byte[] buffer = new byte[len];
        int readLen = 0;
        while (readLen < len) {
            try {
                int read = dis.read(buffer, readLen, len - readLen);
                if (read < 0) {
                    return null;
                } else {
                    readLen += read;
                }
            } catch (IOException e) {
                return null;
            }
        }

        return buffer;
    }


    private void writeTraceData(byte[] buffer, DataOutputStream stream) throws IOException {
        stream.writeInt(buffer.length);
        stream.write(buffer);
    }

    private void updateTraceStats(byte[] buffer) {
        GLMessage msg = null;
        try {
            msg = GLMessage.parseFrom(buffer);
        } catch (InvalidProtocolBufferException e) {
            return;
        }

        mFileSize += buffer.length;

        if (msg.getFunction() == Function.eglSwapBuffers) {
            mFrameCount++;
        }
    }

    public int getCurrentFileSize() {
        return mFileSize;
    }

    public int getCurrentFrameCount() {
        return mFrameCount;
    }
}