From ad425af50a979816261f8f2e3f6f397cc21467a6 Mon Sep 17 00:00:00 2001
From: Kaoru Shoji <0x0badc0de@gmail.com>
Date: Thu, 11 Apr 2024 11:33:51 +0900
Subject: [PATCH] Check if the bluetooth transfer completed

---
 .../blemidi/central/BleMidiCallback.java      |  9 ++++---
 .../blemidi/device/MidiOutputDevice.java      | 24 ++++++++++++++-----
 .../peripheral/BleMidiPeripheralProvider.java | 14 +++++++----
 3 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/central/BleMidiCallback.java b/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/central/BleMidiCallback.java
index 3ab1efe..bb24f2e 100644
--- a/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/central/BleMidiCallback.java
+++ b/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/central/BleMidiCallback.java
@@ -9,6 +9,7 @@
 import android.bluetooth.BluetoothGattDescriptor;
 import android.bluetooth.BluetoothGattService;
 import android.bluetooth.BluetoothProfile;
+import android.bluetooth.BluetoothStatusCodes;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -806,17 +807,19 @@ public void configureAsCentralDevice() {
         }
 
         @Override
-        public void transferData(@NonNull byte[] writeBuffer) throws SecurityException {
+        public boolean transferData(@NonNull byte[] writeBuffer) throws SecurityException {
             try {
                 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
-                    bluetoothGatt.writeCharacteristic(midiOutputCharacteristic, writeBuffer, BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE);
+                    int result = bluetoothGatt.writeCharacteristic(midiOutputCharacteristic, writeBuffer, BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE);
+                    return result == BluetoothStatusCodes.SUCCESS;
                 } else {
                     midiOutputCharacteristic.setValue(writeBuffer);
-                    bluetoothGatt.writeCharacteristic(midiOutputCharacteristic);
+                    return bluetoothGatt.writeCharacteristic(midiOutputCharacteristic);
                 }
             } catch (Throwable ignored) {
                 // android.os.DeadObjectException will be thrown
                 // ignore it
+                return false;
             }
         }
 
diff --git a/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/device/MidiOutputDevice.java b/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/device/MidiOutputDevice.java
index c8750a1..18d67c6 100644
--- a/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/device/MidiOutputDevice.java
+++ b/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/device/MidiOutputDevice.java
@@ -20,8 +20,9 @@ public abstract class MidiOutputDevice {
      * Transfer data
      *
      * @param writeBuffer byte array to write
+     * @return true if transfer succeed
      */
-    protected abstract void transferData(@NonNull byte[] writeBuffer);
+    protected abstract boolean transferData(@NonNull byte[] writeBuffer);
 
     /**
      * Obtains the device name
@@ -79,14 +80,16 @@ public void run() {
                 while (transferDataThreadAlive && isRunning) {
                     synchronized (transferDataStream) {
                         if (writtenDataCount > 0) {
-                            transferData(transferDataStream.toByteArray());
-                            transferDataStream.reset();
-                            writtenDataCount = 0;
+                            if (transferData(transferDataStream.toByteArray())) {
+                                // reset the stream if transfer succeed
+                                transferDataStream.reset();
+                                writtenDataCount = 0;
+                            }
                         }
                     }
 
                     try {
-                        Thread.sleep(10);
+                        Thread.sleep(10); // BluetoothGatt.WRITE_CHARACTERISTIC_TIME_TO_WAIT
                     } catch (InterruptedException ignored) {
                     }
                 }
@@ -238,7 +241,16 @@ public final void sendMidiSystemExclusive(@NonNull byte[] systemExclusive) {
             writeBuffer[0] = (byte) (0x80 | ((timestamp >> 7) & 0x3f));
 
             // immediately transfer data
-            transferData(writeBuffer);
+            while (true) {
+                if (transferData(writeBuffer)) {
+                    break;
+                }
+
+                try {
+                    Thread.sleep(10); // BluetoothGatt.WRITE_CHARACTERISTIC_TIME_TO_WAIT
+                } catch (InterruptedException ignored) {
+                }
+            }
 
             timestamp = System.currentTimeMillis() % MAX_TIMESTAMP;
         }
diff --git a/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/peripheral/BleMidiPeripheralProvider.java b/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/peripheral/BleMidiPeripheralProvider.java
index fd7033d..a567ffa 100644
--- a/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/peripheral/BleMidiPeripheralProvider.java
+++ b/BLE-MIDI-library/src/main/java/jp/kshoji/blemidi/peripheral/BleMidiPeripheralProvider.java
@@ -12,6 +12,7 @@
 import android.bluetooth.BluetoothGattService;
 import android.bluetooth.BluetoothManager;
 import android.bluetooth.BluetoothProfile;
+import android.bluetooth.BluetoothStatusCodes;
 import android.bluetooth.le.AdvertiseCallback;
 import android.bluetooth.le.AdvertiseData;
 import android.bluetooth.le.AdvertiseSettings;
@@ -707,13 +708,18 @@ public String getModel() {
         }
 
         @Override
-        public void transferData(@NonNull byte[] writeBuffer) throws SecurityException {
-            midiOutputCharacteristic.setValue(writeBuffer);
-
+        public boolean transferData(@NonNull byte[] writeBuffer) throws SecurityException {
             try {
-                bluetoothGattServer.notifyCharacteristicChanged(bluetoothDevice, midiOutputCharacteristic, false);
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                    int result = bluetoothGattServer.notifyCharacteristicChanged(bluetoothDevice, midiOutputCharacteristic, false, writeBuffer);
+                    return result == BluetoothStatusCodes.SUCCESS;
+                } else {
+                    midiOutputCharacteristic.setValue(writeBuffer);
+                    return bluetoothGattServer.notifyCharacteristicChanged(bluetoothDevice, midiOutputCharacteristic, false);
+                }
             } catch (Throwable ignored) {
                 // ignore it
+                return false;
             }
         }