Use ConcurrentLinkedQueue to reduce CPU overhead

Since isEmpty method of ConcurrentLinkedQueue may take some time, and
therefore it would not detect new elements offered, we have to wait a time
out to ensure ConcurrentLinkedQueue can detect new elements.

Signed-off-by: Leo Ma <begeekmyfriend@gmail.com>

app/src/main/java/net/ossrs/sea/rtmp/io/WriteThread.java

@@ -3,9 +3,8 @@ package net.ossrs.sea.rtmp.io;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.net.SocketException;
-import android.os.Handler;
-import android.os.Looper;
-import android.os.Message;
+import java.util.Arrays;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import android.util.Log;
 import net.ossrs.sea.rtmp.packets.Command;
 import net.ossrs.sea.rtmp.packets.RtmpPacket;
@@ -21,9 +20,10 @@ public class WriteThread extends Thread {
 
     private RtmpSessionInfo rtmpSessionInfo;
     private OutputStream out;
-    private Handler handler;
+    private ConcurrentLinkedQueue<RtmpPacket> writeQueue = new ConcurrentLinkedQueue<RtmpPacket>();
+    private final Object txPacketLock = new Object();
+    private volatile boolean active = true;
     private ThreadController threadController;
-    private Thread t;
 
     public WriteThread(RtmpSessionInfo rtmpSessionInfo, OutputStream out, ThreadController threadController) {
         super("RtmpWriteThread");
@@ -34,31 +34,43 @@ public class WriteThread extends Thread {
 
     @Override
     public void run() {
-        t = this;
-        Looper.prepare();
-        handler = new Handler(Looper.myLooper()) {
-            @Override
-            public void handleMessage(Message msg) {
-                try {
-                    RtmpPacket rtmpPacket = (RtmpPacket) msg.obj;
-                    ChunkStreamInfo chunkStreamInfo = rtmpSessionInfo.getChunkStreamInfo(rtmpPacket.getHeader().getChunkStreamId());
+
+        while (active) {
+            try {
+                while (!writeQueue.isEmpty()) {
+                    RtmpPacket rtmpPacket = writeQueue.poll();
+                    final ChunkStreamInfo chunkStreamInfo = rtmpSessionInfo.getChunkStreamInfo(rtmpPacket.getHeader().getChunkStreamId());
                     chunkStreamInfo.setPrevHeaderTx(rtmpPacket.getHeader());
                     rtmpPacket.writeTo(out, rtmpSessionInfo.getTxChunkSize(), chunkStreamInfo);
-                    out.flush();
                     Log.d(TAG, "WriteThread: wrote packet: " + rtmpPacket + ", size: " + rtmpPacket.getHeader().getPacketLength());
                     if (rtmpPacket instanceof Command) {
                         rtmpSessionInfo.addInvokedCommand(((Command) rtmpPacket).getTransactionId(), ((Command) rtmpPacket).getCommandName());
                     }
-                } catch (SocketException se) {
-                    Log.e(TAG, "WriteThread: Caught SocketException during write loop, shutting down", se);
-                    Thread.getDefaultUncaughtExceptionHandler().uncaughtException(t, se);
-                } catch (IOException ex) {
-                    Log.e(TAG, "WriteThread: Caught IOException during write loop, shutting down", ex);
-                    Thread.getDefaultUncaughtExceptionHandler().uncaughtException(t, ex);
                 }
+                out.flush();
+            } catch (SocketException se) {
+                Log.e(TAG, "WriteThread: Caught SocketException during write loop, shutting down", se);
+                Thread.getDefaultUncaughtExceptionHandler().uncaughtException(this, se);
+                active = false;
+                continue;
+            } catch (IOException ioe) {
+                Log.e(TAG, "WriteThread: Caught IOException during write loop, shutting down", ioe);
+                Thread.getDefaultUncaughtExceptionHandler().uncaughtException(this, ioe);
+                active = false;
+                continue;
             }
-        };
-        Looper.loop();
+
+            // Waiting for next packet
+            Log.d(TAG, "WriteThread: waiting...");
+            synchronized (txPacketLock) {
+                try {
+                    // isEmpty() may take some time, so time out should be set to wait next offer
+                    txPacketLock.wait(1000);
+                } catch (InterruptedException ex) {
+                    Log.w(TAG, "Interrupted", ex);
+                }
+            }
+        }
 
         // Close outputstream
         try {
@@ -75,14 +87,26 @@ public class WriteThread extends Thread {
     /** Transmit the specified RTMP packet (thread-safe) */
     public void send(RtmpPacket rtmpPacket) {
         if (rtmpPacket != null) {
-            Message msg = Message.obtain();
-            msg.obj = rtmpPacket;
-            handler.sendMessage(msg);
+            writeQueue.offer(rtmpPacket);
+        }
+        synchronized (txPacketLock) {
+            txPacketLock.notify();
+        }
+    }
+    
+    /** Transmit the specified RTMP packet (thread-safe) */
+    public void send(RtmpPacket... rtmpPackets) {
+        writeQueue.addAll(Arrays.asList(rtmpPackets));
+        synchronized (txPacketLock) {
+            txPacketLock.notify();
         }
     }
 
     public void shutdown() {
         Log.d(TAG, "Stopping write thread...");
-        Looper.myLooper().quit();
+        active = false;
+        synchronized (txPacketLock) {
+            txPacketLock.notify();
+        }
     }
 }