From 5f69f9bcf089066eda0ced02bde060240bd59881 Mon Sep 17 00:00:00 2001
From: Aleksander Nowakowski <aleksander.nowakowski@nordicsemi.no>
Date: Wed, 11 Apr 2018 11:36:40 +0200
Subject: [PATCH] MTU value available in the BleManager

---
 .../android/nrftoolbox/ble/BleManager.java    | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/wear/src/main/java/no/nordicsemi/android/nrftoolbox/ble/BleManager.java b/wear/src/main/java/no/nordicsemi/android/nrftoolbox/ble/BleManager.java
index 696d35d6..cb3c0f26 100644
--- a/wear/src/main/java/no/nordicsemi/android/nrftoolbox/ble/BleManager.java
+++ b/wear/src/main/java/no/nordicsemi/android/nrftoolbox/ble/BleManager.java
@@ -101,6 +101,10 @@ public class BleManager implements BleProfileApi {
 	private int mConnectionState = BluetoothGatt.STATE_DISCONNECTED;
 	/** Last received battery value or -1 if value wasn't received. */
 	private int mBatteryValue = -1;
+	/**
+	 * The current MTU (Maximum Transfer Unit). The maximum number of bytes that can be sent in a single packet is MTU-3.
+	 */
+	private int mMtu = 23;
 
 	private final BroadcastReceiver mBluetoothStateBroadcastReceiver = new BroadcastReceiver() {
 		@Override
@@ -579,6 +583,31 @@ public class BleManager implements BleProfileApi {
 		return Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && enqueue(Request.newMtuRequest(mtu));
 	}
 
+	/**
+	 * Returns the current MTU (Maximum Transfer Unit). MTU specifies the maximum number of bytes that can
+	 * be sent in a single write operation. 3 bytes are used for internal purposes, so the maximum size is MTU-3.
+	 * The value will changed only if requested with {@link #requestMtu(int)} and a successful callback is received.
+	 * If the peripheral requests MTU change, the {@link BluetoothGattCallback#onMtuChanged(BluetoothGatt, int, int)}
+	 * callback is not invoked, therefor the returned MTU value will not be correct.
+	 * Use {@link android.bluetooth.BluetoothGattServerCallback#onMtuChanged(BluetoothDevice, int)} to get the
+	 * callback with right value requested from the peripheral side.
+	 * @return the current MTU value. Default to 23.
+	 */
+	protected final int getMtu() {
+		return mMtu;
+	}
+
+	/**
+	 * This method overrides the MTU value. Use it only when the peripheral has changed MTU and you
+	 * received the {@link android.bluetooth.BluetoothGattServerCallback#onMtuChanged(BluetoothDevice, int)}
+	 * callback. If you want to set MTU as a master, use {@link #requestMtu(int)} instead.
+	 * @param mtu the MTU value set by the peripheral.
+	 */
+	protected final void overrideMtu(final int mtu) {
+		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
+			mMtu = mtu;
+	}
+
 	@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
 	private boolean internalRequestMtu(final int mtu) {
 		final BluetoothGatt gatt = mBluetoothGatt;