Android: Implement QLEService:readCharacateristic & readDescriptor

In general we extend the concept of the write queue. Not only do we
queue up write requests but also read requests.

The handling of read errors is still missing. Right now the
QLEService::error() signal is not emitted when a readCharacteristic()
and readDescriptor() call fails.

Change-Id: I4b4f086c351c4a29d6e48e8ee9079e9f33f36539
Reviewed-by: Timur Pocheptsov <Timur.Pocheptsov@digia.com>
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

1 files changed, 192 insertions, 70 deletions

diff --git a/src/android/bluetooth/src/org/qtproject/qt5/android/bluetooth/QtBluetoothLE.java b/src/android/bluetooth/src/org/qtproject/qt5/android/bluetooth/QtBluetoothLE.java
index ffef93dd..6a283fb0 100644
--- a/src/android/bluetooth/src/org/qtproject/qt5/android/bluetooth/QtBluetoothLE.java
+++ b/src/android/bluetooth/src/org/qtproject/qt5/android/bluetooth/QtBluetoothLE.java
@@ -174,6 +174,7 @@ public class QtBluetoothLE {
                                          android.bluetooth.BluetoothGattCharacteristic characteristic,
                                          int status)
         {
+            // TODO test error handling for read requests
             if (status != BluetoothGatt.GATT_SUCCESS) {
                 Log.w(TAG, "onCharacteristicRead error: " + status);
                 return;
@@ -222,10 +223,15 @@ public class QtBluetoothLE {
                     return;
                 }
 
+                synchronized (readWriteQueue) {
+                    ioJobPending = false;
+                }
+
                 leCharacteristicRead(qtObject, characteristic.getService().getUuid().toString(),
                         foundHandle+1, characteristic.getUuid().toString(),
                         characteristic.getProperties(), characteristic.getValue());
 
+                performNextIO();
                 return;
             }
 
@@ -263,11 +269,11 @@ public class QtBluetoothLE {
                     errorCode = 2; break; // CharacteristicWriteError
             }
 
-            synchronized (writeQueue) {
-                writeJobPending = false;
+            synchronized (readWriteQueue) {
+                ioJobPending = false;
             }
             leCharacteristicWritten(qtObject, handle+1, characteristic.getValue(), errorCode);
-            performNextWrite();
+            performNextIO();
         }
 
         public void onCharacteristicChanged(android.bluetooth.BluetoothGatt gatt,
@@ -333,9 +339,15 @@ public class QtBluetoothLE {
                 if (foundHandle == -1)
                     Log.w(TAG, "Out-of-detail-discovery: char update failed");
 
+                synchronized (readWriteQueue) {
+                    ioJobPending = false;
+                }
+
                 leDescriptorRead(qtObject, descriptor.getCharacteristic().getService().getUuid().toString(),
                         descriptor.getCharacteristic().getUuid().toString(), foundHandle+1,
                         descriptor.getUuid().toString(), descriptor.getValue());
+
+                performNextIO();
                 return;
             }
 
@@ -386,12 +398,12 @@ public class QtBluetoothLE {
                     errorCode = 3; break; // DescriptorWriteError
             }
 
-            synchronized (writeQueue) {
-                writeJobPending = false;
+            synchronized (readWriteQueue) {
+                ioJobPending = false;
             }
 
             leDescriptorWritten(qtObject, handle+1, descriptor.getValue(), errorCode);
-            performNextWrite();
+            performNextIO();
         }
         //TODO Requires Android API 21 which is not available on CI yet.
 //        public void onReliableWriteCompleted(android.bluetooth.BluetoothGatt gatt,
@@ -446,11 +458,18 @@ public class QtBluetoothLE {
         public BluetoothGattDescriptor descriptor = null;
         public int endHandle;
     }
-    private class WriteJob
+
+    private enum IoJobType
+    {
+        Read, Write
+    }
+
+    private class ReadWriteJob
     {
         public GattEntry entry;
         public byte[] newValue;
         public int requestedWriteType;
+        public IoJobType jobType;
     }
 
     private final Hashtable<UUID, List<Integer>> uuidToEntry = new Hashtable<UUID, List<Integer>>(100);
@@ -458,8 +477,8 @@ public class QtBluetoothLE {
     private final LinkedList<Integer> servicesToBeDiscovered = new LinkedList<Integer>();
 
 
-    private final LinkedList<WriteJob> writeQueue = new LinkedList<WriteJob>();
-    private boolean writeJobPending;
+    private final LinkedList<ReadWriteJob> readWriteQueue = new LinkedList<ReadWriteJob>();
+    private boolean ioJobPending;
 
     /*
         Internal helper function
@@ -603,8 +622,8 @@ public class QtBluetoothLE {
             entries.clear();
             servicesToBeDiscovered.clear();
         }
-        synchronized (writeQueue) {
-            writeQueue.clear();
+        synchronized (readWriteQueue) {
+            readWriteQueue.clear();
         }
     }
 
@@ -820,15 +839,16 @@ public class QtBluetoothLE {
             return false;
         }
 
-        WriteJob newJob = new WriteJob();
+        ReadWriteJob newJob = new ReadWriteJob();
         newJob.newValue = newValue;
         newJob.entry = entry;
+        newJob.jobType = IoJobType.Write;
 
         // writeMode must be in sync with QLowEnergyService::WriteMode
         // For now we ignore SignedWriteType as Qt doesn't support it yet.
         switch (writeMode) {
             case 1: //WriteWithoutResponse
-                newJob.requestedWriteType = BluetoothGattCharacteristic. WRITE_TYPE_NO_RESPONSE;
+                newJob.requestedWriteType = BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE;
                 break;
             default:
                 newJob.requestedWriteType = BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT;
@@ -836,8 +856,8 @@ public class QtBluetoothLE {
         }
 
         boolean result;
-        synchronized (writeQueue) {
-            result = writeQueue.add(newJob);
+        synchronized (readWriteQueue) {
+            result = readWriteQueue.add(newJob);
         }
 
         if (!result) {
@@ -845,7 +865,7 @@ public class QtBluetoothLE {
             return false;
         }
 
-        performNextWrite();
+        performNextIO();
         return true;
     }
 
@@ -866,14 +886,15 @@ public class QtBluetoothLE {
             return false;
         }
 
-        WriteJob newJob = new WriteJob();
+        ReadWriteJob newJob = new ReadWriteJob();
         newJob.newValue = newValue;
         newJob.entry = entry;
         newJob.requestedWriteType = BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT;
+        newJob.jobType = IoJobType.Write;
 
         boolean result;
-        synchronized (writeQueue) {
-            result = writeQueue.add(newJob);
+        synchronized (readWriteQueue) {
+            result = readWriteQueue.add(newJob);
         }
 
         if (!result) {
@@ -881,39 +902,126 @@ public class QtBluetoothLE {
             return false;
         }
 
-        performNextWrite();
+        performNextIO();
+        return true;
+    }
+
+    /*************************************************************/
+    /* Read Characteristics                                      */
+    /*************************************************************/
+
+    public boolean readCharacteristic(int charHandle)
+    {
+        if (mBluetoothGatt == null)
+            return false;
+
+        GattEntry entry;
+        try {
+            entry = entries.get(charHandle-1); //Qt always uses handles+1
+        } catch (IndexOutOfBoundsException ex) {
+            ex.printStackTrace();
+            return false;
+        }
+
+        ReadWriteJob newJob = new ReadWriteJob();
+        newJob.entry = entry;
+        newJob.jobType = IoJobType.Read;
+
+        boolean result;
+        synchronized (readWriteQueue) {
+            result = readWriteQueue.add(newJob);
+        }
+
+        if (!result) {
+            Log.w(TAG, "Cannot add characteristic read request for " + charHandle + " to queue" );
+            return false;
+        }
+
+        performNextIO();
+        return true;
+    }
+
+    public boolean readDescriptor(int descHandle)
+    {
+        if (mBluetoothGatt == null)
+            return false;
+
+        GattEntry entry;
+        try {
+            entry = entries.get(descHandle-1); //Qt always uses handles+1
+        } catch (IndexOutOfBoundsException ex) {
+            ex.printStackTrace();
+            return false;
+        }
+
+        ReadWriteJob newJob = new ReadWriteJob();
+        newJob.entry = entry;
+        newJob.jobType = IoJobType.Read;
+
+        boolean result;
+        synchronized (readWriteQueue) {
+            result = readWriteQueue.add(newJob);
+        }
+
+        if (!result) {
+            Log.w(TAG, "Cannot add descriptor read request for " + descHandle + " to queue" );
+            return false;
+        }
+
+        performNextIO();
         return true;
     }
 
     /*
-        The queuing is required because two writeCharacteristic/writeDescriptor calls
-        cannot execute at the same time. The second write must happen after the
-        previous write has finished with on(Characteristic|Descriptor)Write().
-     */
-    private void performNextWrite()
+       The queuing is required because two writeCharacteristic/writeDescriptor calls
+       cannot execute at the same time. The second write must happen after the
+       previous write has finished with on(Characteristic|Descriptor)Write().
+    */
+    private void performNextIO()
     {
         if (mBluetoothGatt == null)
             return;
 
         boolean skip = false;
-        final WriteJob nextJob;
-        synchronized (writeQueue) {
-            if (writeQueue.isEmpty() || writeJobPending)
+        final ReadWriteJob nextJob;
+        synchronized (readWriteQueue) {
+            if (readWriteQueue.isEmpty() || ioJobPending)
                 return;
 
-            nextJob = writeQueue.remove();
-            boolean result;
-            switch (nextJob.entry.type) {
-                case Characteristic:
-                    if (nextJob.entry.characteristic.getWriteType() != nextJob.requestedWriteType) {
-                        nextJob.entry.characteristic.setWriteType(nextJob.requestedWriteType);
-                    }
-                    result = nextJob.entry.characteristic.setValue(nextJob.newValue);
-                    if (!result || !mBluetoothGatt.writeCharacteristic(nextJob.entry.characteristic))
-                        skip = true;
-                    break;
-                case Descriptor:
-                    if (nextJob.entry.descriptor.getUuid().compareTo(clientCharacteristicUuid) == 0) {
+            nextJob = readWriteQueue.remove();
+
+            Log.w(TAG, "Performing queued job " + nextJob.jobType);
+            if (nextJob.jobType == IoJobType.Read)
+                skip = executeReadJob(nextJob);
+            else
+                skip = executeWriteJob(nextJob);
+
+            if (!skip)
+                ioJobPending = true;
+        }
+
+        if (skip) {
+            Log.w(TAG, "Skipping: " + nextJob.entry.type);
+            performNextIO();
+        }
+    }
+
+    // Runs inside the Mutex on readWriteQueue.
+    // Returns true if nextJob should be skipped.
+    private boolean executeWriteJob(ReadWriteJob nextJob)
+    {
+        boolean result;
+        switch (nextJob.entry.type) {
+            case Characteristic:
+                if (nextJob.entry.characteristic.getWriteType() != nextJob.requestedWriteType) {
+                    nextJob.entry.characteristic.setWriteType(nextJob.requestedWriteType);
+                }
+                result = nextJob.entry.characteristic.setValue(nextJob.newValue);
+                if (!result || !mBluetoothGatt.writeCharacteristic(nextJob.entry.characteristic))
+                    return true;
+                break;
+            case Descriptor:
+                if (nextJob.entry.descriptor.getUuid().compareTo(clientCharacteristicUuid) == 0) {
                         /*
                             For some reason, Android splits characteristic notifications
                             into two operations. BluetoothGatt.enableCharacteristicNotification
@@ -931,42 +1039,56 @@ public class QtBluetoothLE {
                             Bluetooth spec Vol 3, Part G, 4.11 . If neither of the two bits are set
                             we disable the signals.
                          */
-                        boolean enableNotifications = false;
-                        int value = (nextJob.newValue[0] & 0xff);
-                        // first or second bit must be set
-                        if (((value & 0x1) == 1) || (((value >> 1) & 0x1) == 1)) {
-                            enableNotifications = true;
-                        }
-
-                        result = mBluetoothGatt.setCharacteristicNotification(
-                                nextJob.entry.descriptor.getCharacteristic(), enableNotifications);
-                        if (!result) {
-                            Log.w(TAG, "Cannot set characteristic notification");
-                            //we continue anyway to ensure that we write the requested value
-                            //to the device
-                        }
+                    boolean enableNotifications = false;
+                    int value = (nextJob.newValue[0] & 0xff);
+                    // first or second bit must be set
+                    if (((value & 0x1) == 1) || (((value >> 1) & 0x1) == 1)) {
+                        enableNotifications = true;
+                    }
 
-                        Log.d(TAG, "Enable notifications: " + enableNotifications);
+                    result = mBluetoothGatt.setCharacteristicNotification(
+                            nextJob.entry.descriptor.getCharacteristic(), enableNotifications);
+                    if (!result) {
+                        Log.w(TAG, "Cannot set characteristic notification");
+                        //we continue anyway to ensure that we write the requested value
+                        //to the device
                     }
 
-                    result = nextJob.entry.descriptor.setValue(nextJob.newValue);
-                    if (!result || !mBluetoothGatt.writeDescriptor(nextJob.entry.descriptor))
-                        skip = true;
-                    break;
-                case Service:
-                case CharacteristicValue:
-                    skip = true;
-                    break;
-            }
+                    Log.d(TAG, "Enable notifications: " + enableNotifications);
+                }
 
-            if (!skip)
-                writeJobPending = true;
+                result = nextJob.entry.descriptor.setValue(nextJob.newValue);
+                if (!result || !mBluetoothGatt.writeDescriptor(nextJob.entry.descriptor))
+                    return true;
+                break;
+            case Service:
+            case CharacteristicValue:
+                return true;
         }
+        return false;
+    }
 
-        if (skip) {
-            Log.w(TAG, "Skipping write: " + nextJob.entry.type);
-            performNextWrite();
+    // Runs inside the Mutex on readWriteQueue.
+    // Returns true if nextJob should be skipped.
+    private boolean executeReadJob(ReadWriteJob nextJob)
+    {
+        boolean result;
+        switch (nextJob.entry.type) {
+            case Characteristic:
+                result = mBluetoothGatt.readCharacteristic(nextJob.entry.characteristic);
+                if (!result)
+                    return true; // skip
+                break;
+            case Descriptor:
+                result = mBluetoothGatt.readDescriptor(nextJob.entry.descriptor);
+                if (!result)
+                    return true; // skip
+                break;
+            case Service:
+            case CharacteristicValue:
+                return true;
         }
+        return false;
     }
 
     public native void leConnectionStateChange(long qtObject, int wasErrorTransition, int newState);