Merge branch 'jeremybrodt-readcallback'.

Fixes #33.

public/BLEDevice.h

@@ -250,6 +250,27 @@ public:
     void onDataWritten(void (*callback)(const GattCharacteristicWriteCBParams *eventDataP));
     template <typename T> void onDataWritten(T * objPtr, void (T::*memberPtr)(const GattCharacteristicWriteCBParams *context));
 
+    /**
+     * Setup a callback for when a characteristic is being read by a client.
+     *
+     * @Note: this functionality may not be available on all underlying stacks.
+     * You could use GattCharacteristic::setReadAuthorizationCallback() as an
+     * alternative.
+     *
+     * @Note: it is possible to chain together multiple onDataRead callbacks
+     * (potentially from different modules of an application) to receive updates
+     * to characteristics. Services may add their own onDataRead callbacks
+     * behind the scenes to trap interesting events.
+     *
+     * @Note: it is also possible to setup a callback into a member function of
+     * some object.
+     *
+     * @return BLE_ERROR_NOT_IMPLEMENTED if this functionality isn't available;
+     *         else BLE_ERROR_NONE.
+     */
+    ble_error_t onDataRead(void (*callback)(const GattCharacteristicReadCBParams *eventDataP));
+    template <typename T> ble_error_t onDataRead(T * objPtr, void (T::*memberPtr)(const GattCharacteristicReadCBParams *context));
+
     void onUpdatesEnabled(GattServer::EventCallback_t callback);
     void onUpdatesDisabled(GattServer::EventCallback_t callback);
     void onConfirmationReceived(GattServer::EventCallback_t callback);
@@ -551,6 +572,16 @@ BLEDevice::onDataWritten(T *objPtr, void (T::*memberPtr)(const GattCharacteristi
     transport->getGattServer().setOnDataWritten(objPtr, memberPtr);
 }
 
+inline ble_error_t
+BLEDevice::onDataRead(void (*callback)(const GattCharacteristicReadCBParams *eventDataP)) {
+    return transport->getGattServer().setOnDataRead(callback);
+}
+
+template <typename T> inline ble_error_t
+BLEDevice::onDataRead(T *objPtr, void (T::*memberPtr)(const GattCharacteristicReadCBParams *context)) {
+    return transport->getGattServer().setOnDataRead(objPtr, memberPtr);
+}
+
 inline void
 BLEDevice::onUpdatesEnabled(GattServer::EventCallback_t callback)
 {

public/GattCharacteristicCallbackParams.h

@@ -33,6 +33,17 @@ struct GattCharacteristicWriteCBParams {
     const uint8_t *data;   /**< Incoming data, variable length. */
 };
 
+struct GattCharacteristicReadCBParams {
+    GattAttribute::Handle_t charHandle;
+    enum Type {
+        GATTS_CHAR_OP_INVALID               = 0x00,  /**< Invalid Operation. */
+        GATTS_CHAR_OP_READ_REQ              = 0x0A,  /**< Read Request. */
+    } op;                  /**< Type of write operation, */
+    uint16_t       offset; /**< Offset for the read operation. */
+    uint16_t       *len;   /**< Length of the outgoing data. */
+    uint8_t        *data;  /**< Outgoing data, variable length. */
+};
+
 struct GattCharacteristicWriteAuthCBParams {
     GattAttribute::Handle_t  charHandle;
     uint16_t                 offset; /**< Offset for the write operation. */

public/GattServer.h

@@ -34,6 +34,7 @@ protected:
         characteristicCount(0),
         onDataSent(),
         onDataWritten(),
+        onDataRead(),
         onUpdatesEnabled(NULL),
         onUpdatesDisabled(NULL),
         onConfirmationReceived(NULL) {
@@ -63,6 +64,31 @@ private:
     void setOnDataWritten(T *objPtr, void (T::*memberPtr)(const GattCharacteristicWriteCBParams *context)) {
         onDataWritten.add(objPtr, memberPtr);
     }
+
+    /**
+     * A virtual function to allow underlying stacks to indicate if they support
+     * onDataRead(). It should be overridden to return true as applicable.
+     */
+    virtual bool isOnDataReadAvaialble() const {
+        return false;
+    }
+    ble_error_t setOnDataRead(void (*callback)(const GattCharacteristicReadCBParams *eventDataP)) {
+        if (!isOnDataReadAvaialble()) {
+            return BLE_ERROR_NOT_IMPLEMENTED;
+        }
+
+        onDataRead.add(callback);
+        return BLE_ERROR_NONE;
+    }
+    template <typename T>
+    ble_error_t setOnDataRead(T *objPtr, void (T::*memberPtr)(const GattCharacteristicReadCBParams *context)) {
+        if (!isOnDataReadAvaialble()) {
+            return BLE_ERROR_NOT_IMPLEMENTED;
+        }
+
+        onDataRead.add(objPtr, memberPtr);
+        return BLE_ERROR_NONE;
+    }
     void setOnUpdatesEnabled(EventCallback_t callback) {onUpdatesEnabled = callback;}
     void setOnUpdatesDisabled(EventCallback_t callback) {onUpdatesDisabled = callback;}
     void setOnConfirmationReceived(EventCallback_t callback) {onConfirmationReceived = callback;}
@@ -74,6 +100,12 @@ protected:
         }
     }
 
+    void handleDataReadEvent(const GattCharacteristicReadCBParams *params) {
+        if (onDataRead.hasCallbacksAttached()) {
+            onDataRead.call(params);
+        }
+    }
+
     void handleEvent(GattServerEvents::gattEvent_e type, uint16_t charHandle) {
         switch (type) {
             case GattServerEvents::GATT_EVENT_UPDATES_ENABLED:
@@ -109,6 +141,7 @@ protected:
 private:
     CallChainOfFunctionPointersWithContext<unsigned> onDataSent;
     CallChainOfFunctionPointersWithContext<const GattCharacteristicWriteCBParams *> onDataWritten;
+    CallChainOfFunctionPointersWithContext<const GattCharacteristicReadCBParams *> onDataRead;
     EventCallback_t onUpdatesEnabled;
     EventCallback_t onUpdatesDisabled;
     EventCallback_t onConfirmationReceived;