Fix QtCreator debugging on Android 5.0 devices

Add a socket based handshake method for gdb. The previous file based
method remains for now and can be activated from Qt creator. It will
be used by older creator builds but has the limitation of not working
on 5.0 devices.

The new mechanism works on pre 5.0 devices too.

Task-number: QTCREATORBUG-13418
Change-Id: Ia3ecd1b144b544f52d90940ca885653bcbc477ac
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>

src/android/jar/src/org/qtproject/qt5/android/QtActivityDelegate.java

@@ -72,10 +72,16 @@ import android.view.ViewGroup;
 import android.view.WindowManager;
 import android.view.inputmethod.InputMethodManager;
 
+import java.io.BufferedReader;
+import java.io.DataOutputStream;
 import java.io.File;
 import java.io.FileWriter;
+import java.io.InputStreamReader;
 import java.io.IOException;
 import java.lang.reflect.Method;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.net.SocketException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -488,6 +494,53 @@ public class QtActivityDelegate
         Log.i(QtNative.QtTAG, "DEBUGGER: " + msg);
     }
 
+    private class DebugWaitRunnable implements Runnable {
+
+        public DebugWaitRunnable(int socketPort) throws  IOException {
+            socket = new ServerSocket(socketPort);
+        }
+
+        public boolean wasFailure;
+        private ServerSocket socket;
+
+        public void run() {
+            final int napTime = 200; // milliseconds between file accesses
+            final int timeOut = 30000; // ms until we give up on ping and pong
+            final int maxAttempts = timeOut / napTime;
+
+            try {
+                socket.setSoTimeout(timeOut);
+                debugLog("Waiting for debug socket on port: " + socket.getLocalPort());
+                Socket connectionFromClient = socket.accept();
+                debugLog("Debug socket accepted");
+                BufferedReader inFromClient =
+                        new BufferedReader(new InputStreamReader(connectionFromClient.getInputStream()));
+                DataOutputStream outToClient = new DataOutputStream(connectionFromClient.getOutputStream());
+                outToClient.writeBytes("" + android.os.Process.myPid());
+
+                for (int i = 0; i < maxAttempts; i++) {
+                    String clientData = inFromClient.readLine();
+                    debugLog("Incoming socket " + clientData);
+                    if (!clientData.isEmpty())
+                        break;
+
+                    if (socket.isClosed()) {
+                        wasFailure = true;
+                        break;
+                    }
+                    Thread.sleep(napTime);
+                }
+            } catch (IOException ioEx) {
+                ioEx.printStackTrace();
+                wasFailure = true;
+                Log.e(QtNative.QtTAG,"Can't start debugger" + ioEx.getMessage());
+            } catch (InterruptedException interruptEx) {
+                wasFailure = true;
+                Log.e(QtNative.QtTAG,"Can't start debugger" + interruptEx.getMessage());
+            }
+        }
+    };
+
     public boolean startApplication()
     {
         // start application
@@ -544,9 +597,17 @@ public class QtActivityDelegate
                         String pongFile = extras.getString("pong_file");
                         String gdbserverSocket = extras.getString("gdbserver_socket");
                         String gdbserverCommand = extras.getString("gdbserver_command");
+                        String pingViaSocket = extras.getString("ping_socketport");
                         boolean usePing = pingFile != null;
                         boolean usePong = pongFile != null;
                         boolean useSocket = gdbserverSocket != null;
+                        int pingSocket = 0;
+                        if (pingViaSocket != null) {
+                            try {
+                                pingSocket = Integer.parseInt(pingViaSocket);
+                            } catch (NumberFormatException ignored) { }
+                        }
+                        boolean usePingViaSocket = (pingViaSocket != null && pingSocket > 0);
                         int napTime = 200; // milliseconds between file accesses
                         int timeOut = 30000; // ms until we give up on ping and pong
                         int maxAttempts = timeOut / napTime;
@@ -602,6 +663,20 @@ public class QtActivityDelegate
                             debugLog("socket not used");
                         }
 
+                        if (usePingViaSocket) {
+                            DebugWaitRunnable runnable = new DebugWaitRunnable(pingSocket);
+                            Thread waitThread = new Thread(runnable);
+                            waitThread.start();
+                            waitThread.join();
+
+                            if (runnable.wasFailure) {
+                                debugLog("Could not connect to debug client");
+                                return false;
+                            } else {
+                                debugLog("Got pid acknowledgment");
+                            }
+                        }
+
                         if (usePing) {
                             // Tell we are ready.
                             debugLog("writing ping at " + pingFile);