Improve shutdown to clear BLE API and not just SD

Improve the shutdown functionality, such that a call to ble.shutdown() from
the user application clears the API and nRF5x state and NOT only the
SoftDevice. To achieve this the following changes are introduced:

* Add a protected member cleanup() to nRF5xGap, nRF5xGattClient,
nRF5xGattServer, nRF5xSecurityManager and nRF5xServiceDiscovery.
* Modify the shutdown() implementation in nRF5xn such that it also calls the
static member shutdown() exposed by the BLE API in Gap.h, SecurityManager.h,
GattClient.h and GattServer.h.
* Modify nRF5xGattClient, nRF5xGattServer and nRF5xSecurityManager
classes so that they dynamically create their respective objects only if
needed. Previously the GattClient, GattServer and SecurityManager objects were
declared as static, which means that they were always present even though they
were not always needed. This increases memory consumption unnecessarily.
Furthermore, pointers to the object instances are stored in static members of
the classes as specified by the BLE API base classes. This ensures that
calls to shutdown do not require calls to getInstance() functions that would
otherwise result in undesired memory allocations.
* nRF5xGap object is always needed, so this remains allocated statically. But
the reference in Gap is pointed to this object.

The shutdown procedure is as follows:

1. The user calls ble.shutdown() which executes the code in nRF5xn::shutdown()
1. The SoftDevice is shutdown
1. The static members of Gap.h, SecurityManager.h, GattClient.h and
GattServer.h are called to clean up their own state.

If at any point an error occur during the last step, BLE_ERROR_INVALID_STATE is
returned.

source/nRF5xGap.cpp

@@ -23,6 +23,9 @@
 
 nRF5xGap &nRF5xGap::getInstance() {
     static nRF5xGap m_instance;
+    if (gapInstance == NULL) {
+        gapInstance = &m_instance;
+    }
     return m_instance;
 }
 
@@ -336,6 +339,29 @@ ble_error_t nRF5xGap::updateConnectionParams(Handle_t handle, const ConnectionPa
     }
 }
 
+/**************************************************************************/
+/*!
+    @brief  Clear nRF5xGap's state.
+
+    @returns    ble_error_t
+
+    @retval     BLE_ERROR_NONE
+                Everything executed properly
+*/
+/**************************************************************************/
+ble_error_t nRF5xGap::cleanup(void)
+{
+    /* Clear all state that is from the parent, including private members */
+    if (Gap::cleanup() != BLE_ERROR_NONE) {
+        return BLE_ERROR_INVALID_STATE;
+    }
+
+    /* Clear derived class members */
+    m_connectionHandle = BLE_CONN_HANDLE_INVALID;
+
+    return BLE_ERROR_NONE;
+}
+
 /**************************************************************************/
 /*!
     @brief  Sets the 16-bit connection handle
@@ -356,7 +382,7 @@ uint16_t nRF5xGap::getConnectionHandle(void)
     return m_connectionHandle;
 }
 
-/**************************************************************************/
+/**************5************************************************************/
 /*!
     @brief      Sets the BLE device address
 

source/nRF5xGap.h

@@ -112,6 +112,9 @@ public:
     }
 #endif
 
+protected:
+    virtual ble_error_t cleanup(void);
+
 private:
     bool    radioNotificationCallbackParam; /* parameter to be passed into the Timeout-generated radio notification callback. */
     Timeout radioNotificationTimeout;

source/nRF5xGattClient.cpp

@@ -18,11 +18,10 @@
 
 nRF5xGattClient &
 nRF5xGattClient::getInstance(void) {
-    static nRF5xGattClient* nRFGattClientSingleton = NULL;
-    if (nRFGattClientSingleton == NULL) {
-        nRFGattClientSingleton = new nRF5xGattClient();
+    if (gattClientInstance == NULL) {
+        gattClientInstance = new nRF5xGattClient();
     }
-    return *nRFGattClientSingleton;
+    return (nRF5xGattClient &) *gattClientInstance;
 }
 
 #if !defined(TARGET_MCU_NRF51_16K_S110) && !defined(TARGET_MCU_NRF51_32K_S110)

source/nRF5xGattClient.h

@@ -147,6 +147,25 @@ public:
         }
     }
 
+protected:
+    /**
+     * @brief  Clear nRF5xGattClient's state.
+     *
+     * @return
+     *           BLE_ERROR_NONE if successful.
+     */
+    virtual ble_error_t cleanup(void) {
+        /* Clear all state that is from the parent, including private members */
+        if (GattClient::cleanup() != BLE_ERROR_NONE) {
+            return BLE_ERROR_INVALID_STATE;
+        }
+
+        /* Clear derived class members */
+        discovery.cleanup();
+
+        return BLE_ERROR_NONE;
+    }
+
 public:
     nRF5xGattClient() : discovery(this) {
         /* empty */

source/nRF5xGattServer.cpp

@@ -23,8 +23,10 @@
 #include "nRF5xGap.h"
 
 nRF5xGattServer &nRF5xGattServer::getInstance(void) {
-    static nRF5xGattServer m_instance;
-    return m_instance;
+    if (gattServerInstance == NULL) {
+        gattServerInstance = new nRF5xGattServer();
+    }
+    return (nRF5xGattServer &) *gattServerInstance;
 }
 
 /**************************************************************************/
@@ -310,6 +312,33 @@ ble_error_t nRF5xGattServer::areUpdatesEnabled(Gap::Handle_t connectionHandle, c
     return BLE_ERROR_NONE;
 }
 
+/**************************************************************************/
+/*!
+    @brief  Clear nRF5xGattServer's state.
+
+    @returns    ble_error_t
+
+    @retval     BLE_ERROR_NONE
+                Everything executed properly
+*/
+/**************************************************************************/
+ble_error_t nRF5xGattServer::cleanup(void)
+{
+    /* Clear all state that is from the parent, including private members */
+    if (GattServer::cleanup() != BLE_ERROR_NONE) {
+        return BLE_ERROR_INVALID_STATE;
+    }
+
+    /* Clear derived class members */
+    memset(p_characteristics,        0, sizeof(p_characteristics));
+    memset(p_descriptors,            0, sizeof(p_descriptors));
+    memset(nrfCharacteristicHandles, 0, sizeof(ble_gatts_char_handles_t));
+    memset(nrfDescriptorHandles,     0, sizeof(nrfDescriptorHandles));
+    descriptorCount = 0;
+
+    return BLE_ERROR_NONE;
+}
+
 /**************************************************************************/
 /*!
     @brief  Callback handler for events getting pushed up from the SD

source/nRF5xGattServer.h

@@ -42,6 +42,9 @@ public:
     void eventCallback(void);
     void hwCallback(ble_evt_t *p_ble_evt);
 
+protected:
+    virtual ble_error_t cleanup(void);
+
 private:
     const static unsigned BLE_TOTAL_CHARACTERISTICS = 20;
     const static unsigned BLE_TOTAL_DESCRIPTORS     = 8;

source/nRF5xSecurityManager.cpp

@@ -17,9 +17,8 @@
 #include "nRF5xSecurityManager.h"
 
 nRF5xSecurityManager &nRF5xSecurityManager::getInstance(void) {
-    static nRF5xSecurityManager* m_instance = NULL;
-    if (m_instance == NULL) {
-        m_instance = new nRF5xSecurityManager();
+    if (securityManagerInstance == NULL) {
+        securityManagerInstance = new nRF5xSecurityManager();
     }
-    return *m_instance;
+    return (nRF5xSecurityManager &) *securityManagerInstance;
 }

source/nRF5xSecurityManager.h

@@ -47,6 +47,21 @@ public:
         return btle_purgeAllBondingState();
     }
 
+    /**
+     * @brief  Clear nRF5xSecurityManager's state.
+     *
+     * @return
+     *           BLE_ERROR_NONE if successful.
+     */
+    virtual ble_error_t cleanup(void)
+    {
+        if (SecurityManager::cleanup() != BLE_ERROR_NONE) {
+            return BLE_ERROR_INVALID_STATE;
+        }
+
+        return BLE_ERROR_NONE;
+    }
+
 public:
     nRF5xSecurityManager() {
         /* empty */

source/nRF5xServiceDiscovery.h

@@ -99,6 +99,34 @@ public:
         onTerminationCallback = callback;
     }
 
+    /**
+     * @brief  Clear nRF5xServiceDiscovery's state.
+     *
+     * @return
+     *           BLE_ERROR_NONE if successful.
+     */
+    virtual ble_error_t cleanup(void) {
+        /* Clear all state that is from the parent, including private members */
+        if (ServiceDiscovery::cleanup() != BLE_ERROR_NONE) {
+            return BLE_ERROR_INVALID_STATE;
+        }
+
+        /* Clear derived class members */
+        serviceIndex = 0;
+        numServices = 0;
+        characteristicIndex = 0;
+        numCharacteristics = 0;
+
+        state = INACTIVE;
+
+        serviceUUIDDiscoveryQueue.reset();
+        charUUIDDiscoveryQueue.reset();
+
+        onTerminationCallback = NULL;
+
+        return BLE_ERROR_NONE;
+    }
+
 private:
     ble_error_t launchCharacteristicDiscovery(Gap::Handle_t connectionHandle, Gap::Handle_t startHandle, Gap::Handle_t endHandle);
 

source/nRF5xn.cpp

@@ -104,16 +104,44 @@ ble_error_t nRF5xn::init(BLE::InstanceID_t instanceID, FunctionPointerWithContex
     return BLE_ERROR_NONE;
 }
 
+/**************************************************************************/
+/*!
+    @brief  Purge the BLE stack of GATT and GAP state.
+
+    @returns    ble_error_t
+
+    @retval     BLE_ERROR_NONE
+                Everything executed properly
+
+    @note  When using S110, GattClient::shutdown() will not be called
+           since Gatt client features are not supported.
+*/
+/**************************************************************************/
 ble_error_t nRF5xn::shutdown(void)
 {
     if (!initialized) {
         return BLE_ERROR_INITIALIZATION_INCOMPLETE;
     }
 
+    /* Shutdown the SoftDevice */
     if(softdevice_handler_sd_disable() != NRF_SUCCESS) {
         return BLE_STACK_BUSY;
     }
 
+    /* Shutdown the BLE API and nRF51 glue code */
+#if !defined(TARGET_MCU_NRF51_16K_S110) && !defined(TARGET_MCU_NRF51_32K_S110)
+    if (GattServer::shutdown()      != BLE_ERROR_NONE ||
+        SecurityManager::shutdown() != BLE_ERROR_NONE ||
+        GattClient::shutdown()      != BLE_ERROR_NONE ||
+        Gap::shutdown()             != BLE_ERROR_NONE) {
+#else
+    if (GattServer::shutdown()      != BLE_ERROR_NONE ||
+        SecurityManager::shutdown() != BLE_ERROR_NONE ||
+        Gap::shutdown()             != BLE_ERROR_NONE) {
+#endif
+        return BLE_ERROR_INVALID_STATE;
+    }
+
     initialized = false;
     return BLE_ERROR_NONE;
 }