Add GodotNetUtils Java class for Android.

Provides access to a MulticastLock.
As specified by the Android API, broadcast/multicast packets may be
filtered on some phones unless the application explicitly acquires
a "MulticastLock".

3 files changed, 105 insertions, 0 deletions

diff --git a/platform/android/java/lib/src/org/godotengine/godot/Godot.java b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
index 4dae2dcc53..d951998632 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/Godot.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
@@ -96,6 +96,7 @@ import java.util.Locale;
 import javax.microedition.khronos.opengles.GL10;
 import org.godotengine.godot.input.GodotEditText;
 import org.godotengine.godot.payments.PaymentsManager;
+import org.godotengine.godot.utils.GodotNetUtils;
 import org.godotengine.godot.utils.PermissionsUtil;
 import org.godotengine.godot.xr.XRMode;
 
@@ -243,6 +244,7 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 	private Sensor mGyroscope;
 
 	public static GodotIO io;
+	public static GodotNetUtils netUtils;
 
 	static SingletonBase[] singletons = new SingletonBase[MAX_SINGLETONS];
 	static int singleton_count = 0;
@@ -502,6 +504,7 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 		io = new GodotIO(this);
 		io.unique_id = Secure.getString(getContentResolver(), Secure.ANDROID_ID);
 		GodotLib.io = io;
+		netUtils = new GodotNetUtils(this);
 		mSensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
 		mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
 		mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_GAME);
diff --git a/platform/android/java/lib/src/org/godotengine/godot/utils/GodotNetUtils.java b/platform/android/java/lib/src/org/godotengine/godot/utils/GodotNetUtils.java
new file mode 100644
index 0000000000..0dc6962ca6
--- /dev/null
+++ b/platform/android/java/lib/src/org/godotengine/godot/utils/GodotNetUtils.java
@@ -0,0 +1,84 @@
+/*************************************************************************/
+/*  GodotNetUtils.java                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+package org.godotengine.godot.utils;
+
+import android.content.Context;
+import android.net.wifi.WifiManager;
+import android.util.Log;
+
+import org.godotengine.godot.Godot;
+
+/**
+ * This class handles Android-specific networking functions.
+ * For now, it only provides access to WifiManager.MulticastLock, which is needed on some devices
+ * to receive broadcast and multicast packets.
+ */
+public class GodotNetUtils {
+
+	/* A single, reference counted, multicast lock, or null if permission CHANGE_WIFI_MULTICAST_STATE is missing */
+	private WifiManager.MulticastLock multicastLock;
+
+	public GodotNetUtils(Godot p_activity) {
+		if (PermissionsUtil.hasManifestPermission(p_activity, "android.permission.CHANGE_WIFI_MULTICAST_STATE")) {
+			WifiManager wifi = (WifiManager)p_activity.getApplicationContext().getSystemService(Context.WIFI_SERVICE);
+			multicastLock = wifi.createMulticastLock("GodotMulticastLock");
+			multicastLock.setReferenceCounted(true);
+		}
+	}
+
+	/**
+	 * Acquire the multicast lock. This is required on some devices to receive broadcast/multicast packets.
+	 * This is done automatically by Godot when enabling broadcast or joining a multicast group on a socket.
+	 */
+	public void multicastLockAcquire() {
+		if (multicastLock == null)
+			return;
+		try {
+			multicastLock.acquire();
+		} catch (RuntimeException e) {
+			Log.e("Godot", "Exception during multicast lock acquire: " + e);
+		}
+	}
+
+	/**
+	 * Release the multicast lock.
+	 * This is done automatically by Godot when the lock is no longer needed by a socket.
+	 */
+	public void multicastLockRelease() {
+		if (multicastLock == null)
+			return;
+		try {
+			multicastLock.release();
+		} catch (RuntimeException e) {
+			Log.e("Godot", "Exception during multicast lock release: " + e);
+		}
+	}
+}
diff --git a/platform/android/java/lib/src/org/godotengine/godot/utils/PermissionsUtil.java b/platform/android/java/lib/src/org/godotengine/godot/utils/PermissionsUtil.java
index 21df5a91b0..7e35417c6a 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/utils/PermissionsUtil.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/utils/PermissionsUtil.java
@@ -162,6 +162,24 @@ public final class PermissionsUtil {
 	}
 
 	/**
+	 * Check if the given permission is in the AndroidManifest.xml file.
+	 * @param activity the caller activity for this method.
+	 * @param permission the permession to look for in the manifest file.
+	 * @return "true" if the permission is in the manifest file of the activity, "false" otherwise.
+	 */
+	public static boolean hasManifestPermission(Godot activity, String permission) {
+		try {
+			for (String p : getManifestPermissions(activity)) {
+				if (permission.equals(p))
+					return true;
+			}
+		} catch (PackageManager.NameNotFoundException e) {
+		}
+
+		return false;
+	}
+
+	/**
 	 * Returns the permissions defined in the AndroidManifest.xml file.
 	 * @param activity the caller activity for this method.
 	 * @return manifest permissions list