Added callback frontend

docs/changelog.rst

@@ -16,8 +16,9 @@ The format is based on `Keep a Changelog`_, and this project adheres to `Semanti
 
 **Added**
 
-- (Windows) Added support for powering on and off the adapter.
+- (Windows) Added support for powering adapters on and off.
 - (Python) Exposed the `Adapter::power_on()`, `Adapter::power_off()` and `Adapter::is_powered()` methods.
+- Callbacks to monitor adapter power on and off events.
 
 **Changed**
 

simpleble/CMakeLists.txt

@@ -41,6 +41,7 @@ set(SIMPLEBLE_SRC
     ${CMAKE_CURRENT_SOURCE_DIR}/src/frontends/base/Descriptor.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/frontends/base/Backend.cpp
 
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/backends/common/AdapterBase.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/backends/common/ServiceBase.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/backends/common/CharacteristicBase.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/backends/common/DescriptorBase.cpp

simpleble/include/simpleble/Adapter.h

@@ -47,11 +47,15 @@ class SIMPLEBLE_EXPORT Adapter {
     /**
      * Control the power state of the adapter.
      *
-     * This is only supported on Windows and Linux (implementation pending).
+     * NOTE: The power on/off functionality is only supported on Windows and Linux (implementation pending).
+     *       On other platforms, this method will do nothing.
+     * NOTE: Callbacks are currently a placeholder for future implementation.
      */
     void power_on();
     void power_off();
     bool is_powered();
+    void set_callback_on_power_on(std::function<void()> on_power_on);
+    void set_callback_on_power_off(std::function<void()> on_power_off);
 
     void scan_start();
     void scan_stop();

simpleble/src/backends/common/AdapterBase.cpp

@@ -0,0 +1,21 @@
+#include "AdapterBase.h"
+
+namespace SimpleBLE {
+
+void AdapterBase::set_callback_on_power_on(std::function<void()> on_power_on) {
+    if (on_power_on) {
+        _callback_on_power_on.load(on_power_on);
+    } else {
+        _callback_on_power_on.unload();
+    }
+}
+
+void AdapterBase::set_callback_on_power_off(std::function<void()> on_power_off) {
+    if (on_power_off) {
+        _callback_on_power_off.load(on_power_off);
+    } else {
+        _callback_on_power_off.unload();
+    }
+}
+
+}

simpleble/src/backends/common/AdapterBase.h

@@ -5,11 +5,11 @@
 #include <string>
 #include <vector>
 
-#include <simpleble/export.h>
-
 #include <simpleble/Exceptions.h>
 #include <simpleble/Types.h>
 
+#include <kvn_safe_callback.hpp>
+
 namespace SimpleBLE {
 
 class Peripheral;
@@ -22,7 +22,6 @@ class PeripheralBase;
  *
  * Notes for implementers:
  *
- * - The `initialize()` method is not present because internally we enforce RAII.
  * - The methods here return shared pointers to AdapterBase, PeripheralBase,
  *   etc. The code in Adapter.cpp will automatically wrap these in Adapter,
  *   Peripheral, etc. objects.
@@ -39,10 +38,11 @@ class AdapterBase {
     virtual std::string identifier() = 0;
     virtual BluetoothAddress address() = 0;
 
-    // NOTE: A default implementation is provided for these methods until all backends have implemented them.
     virtual void power_on() = 0;
     virtual void power_off() = 0;
     virtual bool is_powered() = 0;
+    virtual void set_callback_on_power_on(std::function<void()> on_power_on);
+    virtual void set_callback_on_power_off(std::function<void()> on_power_off);
 
     virtual void scan_start() = 0;
     virtual void scan_stop() = 0;
@@ -67,6 +67,9 @@ class AdapterBase {
 
   protected:
     AdapterBase() = default;
+
+    kvn::safe_callback<void()> _callback_on_power_on;
+    kvn::safe_callback<void()> _callback_on_power_off;
 };
 
 }  // namespace SimpleBLE

simpleble/src/frontends/base/Adapter.cpp

@@ -56,6 +56,14 @@ void Adapter::power_off() { (*this)->power_off(); }
 
 bool Adapter::is_powered() { return (*this)->is_powered(); }
 
+void Adapter::set_callback_on_power_on(std::function<void()> on_power_on) {
+    (*this)->set_callback_on_power_on(std::move(on_power_on));
+}
+
+void Adapter::set_callback_on_power_off(std::function<void()> on_power_off) {
+    (*this)->set_callback_on_power_off(std::move(on_power_off));
+}
+
 void Adapter::scan_start() {
     if (!bluetooth_enabled()) {
         SIMPLEBLE_LOG_WARN(fmt::format("Bluetooth is not enabled."));