Direct IP connect functionality for AppRTC Android demo.

webrtc/examples/androidapp/src/org/appspot/apprtc/DirectRTCClient.java

Index: webrtc/examples/androidapp/src/org/appspot/apprtc/DirectRTCClient.java
diff --git a/webrtc/examples/androidapp/src/org/appspot/apprtc/DirectRTCClient.java b/webrtc/examples/androidapp/src/org/appspot/apprtc/DirectRTCClient.java
new file mode 100644
index 0000000000000000000000000000000000000000..39ae986b11fe6eb556b149a7c8d1f9f26fb7a85e
--- /dev/null
+++ b/webrtc/examples/androidapp/src/org/appspot/apprtc/DirectRTCClient.java
@@ -0,0 +1,336 @@
+/*
+ *  Copyright 2015 The WebRTC Project Authors. All rights reserved.

[magjed_webrtc, 2016/05/10 14:50:02]

nit: 2016

[sakal, 2016/05/11 08:38:50]

Done.

+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+package org.appspot.apprtc;
+
+import android.util.Log;
+
+import org.appspot.apprtc.util.LooperExecutor;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.webrtc.IceCandidate;
+import org.webrtc.PeerConnection;
+import org.webrtc.SessionDescription;
+
+import java.util.LinkedList;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Implementation of AppRTCClient that uses direct TCP connection as the signaling channel.
+ * This eliminates the need for an external server. This class should not be used for loopback
+ * connections. They are not supported.

[magjed_webrtc, 2016/05/10 14:50:02]

nit: Merge last two sentences to something like: "This class does not support
loopback connections."

[sakal, 2016/05/11 08:38:50]

Done.

+ */
+public class DirectRTCClient implements AppRTCClient, TCPChannelClient.TCPChannelEvents {
+  private static final String TAG = "DirectRTCClient";
+  private static final int DEFAULT_PORT = 8888;
+
+  // Regex pattern used for checking if room id looks like an IP.
+  static final Pattern IP_PATTERN = Pattern.compile(
+          "("

[magjed_webrtc, 2016/05/10 14:50:02]

nit: 4 space indent. Same for other places as well.

[sakal, 2016/05/11 08:38:49]

Done.

+            // IPv4
+            + "((\\d+\\.){3}\\d+)|"
+            // IPv6
+            + "\\[((([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})?::"
+                  + "(([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})?)\\]|"
+            + "\\[(([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})\\]|"
+            // IPv6 without []
+            + "((([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})?::(([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})?)|"
+            + "(([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})|"
+            // Literals
+            + "localhost"
+          + ")"
+          // Optional port number
+          + "(:\\d+)?"
+  );
+
+  private final LooperExecutor executor;
+  private final SignalingEvents events;
+  private TCPChannelClient tcpClient;
+  private RoomConnectionParameters connectionParameters;
+
+  private enum ConnectionState {
+    NEW, CONNECTED, CLOSED, ERROR
+  };
+
+  // All alterations of the room state should be done from inside the looper thread
+  private ConnectionState roomState;
+
+  public DirectRTCClient(SignalingEvents events) {
+    this.events = events;
+    executor = new LooperExecutor();
+
+    executor.requestStart();
+    roomState = ConnectionState.NEW;
+  }
+
+  /**
+   * Connects to the room, roomId in connectionsParameters is required. roomId must be a valid
+   * IP address matching IP_PATTERN.
+   */
+  @Override
+  public void connectToRoom(RoomConnectionParameters connectionParameters) {
+    this.connectionParameters = connectionParameters;
+
+    // Loopback connections should always use the WebSocketRTCClient

[magjed_webrtc, 2016/05/10 14:50:02]

nit: The code is very clear, so I would just remove these two comments.

[sakal, 2016/05/11 08:38:50]

Done.

+    // They are not supported by this client
+    if (connectionParameters.loopback) {
+      reportError("Loopback connections aren't supported by DirectRTCClient.");
+    }
+
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        connectToRoomInternal();
+      }
+    });
+  }
+
+  @Override
+  public void disconnectFromRoom() {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        disconnectFromRoomInternal();
+      }
+    });
+    executor.requestStop();
+  }
+
+  /**
+   * Connects to the room.
+   *
+   * Runs on the looper thread.
+   */
+  private void connectToRoomInternal() {
+    this.roomState = ConnectionState.NEW;
+
+    String endpoint = connectionParameters.roomId;
+
+    Matcher matcher = IP_PATTERN.matcher(endpoint);
+    matcher.matches();

[magjed_webrtc, 2016/05/10 14:50:02]

Check if matches() returns false and/or check IllegalStateException when calling
mather.group() and reportError in those cases.

[sakal, 2016/05/11 08:38:50]

Done.

+
+    String ip = matcher.group(1);
+    String portStr = endpoint.substring(ip.length());

[magjed_webrtc, 2016/05/10 14:50:02]

nit: I think it's a little bit clearer if you use matcher.group(2). I think it
will return null in the case of no port number.

[sakal, 2016/05/11 08:38:49]

matcher.group(2) would returns some part inside the IP address depending on the
format. We can use matcher.group(matcher.groupCount()) though. Done.

+    int port;
+
+    if (!portStr.isEmpty()) {
+      port = Integer.parseInt(portStr.substring(1));
+    } else {
+      port = DEFAULT_PORT;
+    }
+
+    tcpClient = new TCPChannelClient(executor, this, ip, port);
+  }
+
+  /**
+   * Disconnects from the room.
+   *
+   * Runs on the looper thread.
+   */
+  private void disconnectFromRoomInternal() {
+    roomState = ConnectionState.CLOSED;
+
+    if (tcpClient != null) {
+      tcpClient.disconnect();
+      tcpClient = null;
+    }
+  }
+
+  @Override
+  public void sendOfferSdp(final SessionDescription sdp) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        if (roomState != ConnectionState.CONNECTED) {
+          reportError("Sending offer SDP in non connected state.");
+          return;
+        }
+        JSONObject json = new JSONObject();
+        jsonPut(json, "sdp", sdp.description);
+        jsonPut(json, "type", "offer");
+        sendMessage(json.toString());
+      }
+    });
+  }
+
+  @Override
+  public void sendAnswerSdp(final SessionDescription sdp) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        JSONObject json = new JSONObject();
+        jsonPut(json, "sdp", sdp.description);
+        jsonPut(json, "type", "answer");
+        sendMessage(json.toString());
+      }
+    });
+  }
+
+  @Override
+  public void sendLocalIceCandidate(final IceCandidate candidate) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        JSONObject json = new JSONObject();
+        jsonPut(json, "type", "candidate");
+        jsonPut(json, "label", candidate.sdpMLineIndex);
+        jsonPut(json, "id", candidate.sdpMid);
+        jsonPut(json, "candidate", candidate.sdp);
+
+        if (roomState != ConnectionState.CONNECTED) {
+          reportError("Sending ICE candidate in non connected state.");
+          return;
+        }
+        sendMessage(json.toString());
+      }
+    });
+  }
+
+  /** Send removed Ice candidates to the other participant. */
+  @Override
+  public void sendLocalIceCandidateRemovals(final IceCandidate[] candidates) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        JSONObject json = new JSONObject();
+        jsonPut(json, "type", "remove-candidates");
+        JSONArray jsonArray =  new JSONArray();
+        for (final IceCandidate candidate : candidates) {
+          jsonArray.put(toJsonCandidate(candidate));
+        }
+        jsonPut(json, "candidates", jsonArray);
+
+        if (roomState != ConnectionState.CONNECTED) {
+          reportError("Sending ICE candidate removals in non connected state.");
+          return;
+        }
+        sendMessage(json.toString());
+      }
+    });
+  }
+
+  // -------------------------------------------------------------------
+  // TCPChannelClient event handlers
+
+  /**
+   * If the client is the server side, this will trigger onConnectedToRoom.
+   *
+   * @param isServer
+   */
+  @Override
+  public void onTCPConnected(boolean isServer) {
+    if (isServer) {
+      roomState = ConnectionState.CONNECTED;
+
+      SignalingParameters parameters = new SignalingParameters(
+              new LinkedList<PeerConnection.IceServer>(), isServer, null, null, null, null, null);

[magjed_webrtc, 2016/05/10 14:50:02]

nit: Add comments about the null parameters, e.g. null /* clientId */.

[sakal, 2016/05/11 08:38:50]

Done.

+      events.onConnectedToRoom(parameters);
+    }
+  }
+
+  @Override
+  public void onTCPMessage(String msg) {
+    try {
+      JSONObject json = new JSONObject(msg);
+      String type = json.optString("type");
+      if (type.equals("candidate")) {
+        events.onRemoteIceCandidate(toJavaCandidate(json));
+      } else if (type.equals("remove-candidates")) {
+        JSONArray candidateArray = json.getJSONArray("candidates");
+        IceCandidate[] candidates = new IceCandidate[candidateArray.length()];
+        for (int i = 0; i < candidateArray.length(); ++i) {
+          candidates[i] = toJavaCandidate(candidateArray.getJSONObject(i));
+        }
+        events.onRemoteIceCandidatesRemoved(candidates);
+      } else if (type.equals("answer")) {
+        SessionDescription sdp = new SessionDescription(
+                SessionDescription.Type.fromCanonicalForm(type),
+                json.getString("sdp"));
+        events.onRemoteDescription(sdp);
+      } else if (type.equals("offer")) {
+        SessionDescription sdp = new SessionDescription(
+                SessionDescription.Type.fromCanonicalForm(type),
+                json.getString("sdp"));
+
+        SignalingParameters parameters = new SignalingParameters(
+                new LinkedList<PeerConnection.IceServer>(), false, null, null, null, sdp, null);

[magjed_webrtc, 2016/05/10 14:50:02]

ditto: Add comments about the null parameters, e.g. null /* clientId */.

[sakal, 2016/05/11 08:38:49]

Done.

+        roomState = ConnectionState.CONNECTED;
+        events.onConnectedToRoom(parameters);
+      } else if (type.equals("bye")) {
+        events.onChannelClose();
+      } else {
+        reportError("Unexpected TCP message: " + msg);
+      }
+    } catch (JSONException e) {
+      reportError("TCP message JSON parsing error: " + e.toString());
+    }
+  }
+
+  @Override
+  public void onTCPError(String description) {
+    reportError("TCP connection error: " + description);
+  }
+
+  @Override
+  public void onTCPClose() {
+    events.onChannelClose();
+  }
+
+  // --------------------------------------------------------------------
+  // Helper functions.
+  private void reportError(final String errorMessage) {
+    Log.e(TAG, errorMessage);
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        if (roomState != ConnectionState.ERROR) {
+          roomState = ConnectionState.ERROR;
+          events.onChannelError(errorMessage);
+        }
+      }
+    });
+  }
+
+  private void sendMessage(final String message) {
+    executor.execute(new Runnable() {
+      @Override
+      public void run() {
+        tcpClient.send(message);
+      }
+    });
+  }
+
+  // Put a |key|->|value| mapping in |json|.
+  private static void jsonPut(JSONObject json, String key, Object value) {
+    try {
+      json.put(key, value);
+    } catch (JSONException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  // Converts a Java candidate to a JSONObject.
+  private static JSONObject toJsonCandidate(final IceCandidate candidate) {
+    JSONObject json = new JSONObject();
+    jsonPut(json, "label", candidate.sdpMLineIndex);
+    jsonPut(json, "id", candidate.sdpMid);
+    jsonPut(json, "candidate", candidate.sdp);
+    return json;
+  }
+
+  // Converts a JSON candidate to a Java object.
+  private static IceCandidate toJavaCandidate(JSONObject json) throws JSONException {
+    return new IceCandidate(json.getString("id"),
+            json.getInt("label"),
+            json.getString("candidate"));
+  }
+}