Fully implement Root and virutal Feature class

src/logid/backend/hidpp20/Feature.cpp

@@ -1,13 +1,15 @@
 #include "Feature.h"
+#include "feature_defs.h"
+#include "features/Root.h"
 
 using namespace logid::backend::hidpp20;
 
-const char* Feature::UnsupportedFeature::what() const noexcept
+const char* UnsupportedFeature::what() const noexcept
 {
     return "Unsupported feature";
 }
 
-uint16_t Feature::UnsupportedFeature::code() const noexcept
+uint16_t UnsupportedFeature::code() const noexcept
 {
     return _f_id;
 }
@@ -17,12 +19,20 @@ std::vector<uint8_t> Feature::callFunction(uint8_t function_id, std::vector<uint
     return _device->callFunction(_index, function_id, params);
 }
 
-Feature::Feature(Device* dev, uint16_t _id) : _device (dev), _index (0xff)
+Feature::Feature(Device* dev, uint16_t _id) : _device (dev)
 {
-    ///TODO: Set index
-}
+    _index = hidpp20::FeatureID::ROOT;
 
-Feature::Feature(Device* dev, uint8_t _index) : _device (dev), _index (_index)
-{
+    if(_id)
+    {
+        std::vector<uint8_t> getFunc_req(2);
+        getFunc_req[0] = _id & 0xff;
+        getFunc_req[1] = (_id >> 8) & 0xff;
+        auto getFunc_resp = this->callFunction(Root::GetFeature, getFunc_req);
+        _index = getFunc_resp[0];
 
+        // 0 if not found
+        if(!_index)
+            throw UnsupportedFeature(_id);
+    }
 }

src/logid/backend/hidpp20/Feature.h

@@ -7,8 +7,6 @@
 namespace logid {
 namespace backend {
 namespace hidpp20 {
-    class Feature
-    {
     class UnsupportedFeature : public std::exception
     {
     public:
@@ -19,13 +17,14 @@ namespace hidpp20 {
         uint16_t _f_id;
     };
 
+    class Feature
+    {
     public:
         static const uint16_t ID;
         virtual uint16_t getID() = 0;
 
     protected:
         explicit Feature(Device* dev, uint16_t _id);
-        explicit Feature(Device* dev, uint8_t _index);
         std::vector<uint8_t> callFunction(uint8_t function_id,
             std::vector<uint8_t>& params);
     private:

src/logid/backend/hidpp20/features/Root.cpp

@@ -4,22 +4,33 @@ using namespace logid::backend::hidpp20;
 
 Root::Root(Device* dev) : Feature(dev, ID)
 {
-
 }
 
 feature_info Root::getFeature(uint16_t feature_id)
 {
-    feature_info info;
+    feature_info info{};
     std::vector<uint8_t> params(2);
     params[0] = feature_id & 0xff;
     params[1] = (feature_id >> 8) & 0xff;
 
-    auto response = this->callFunction(Function::Ping, params);
+    auto response = this->callFunction(Function::GetFeature, params);
 
     info.feature_id = response[0];
+
+    if(!info.feature_id)
+        throw UnsupportedFeature(feature_id);
+
     info.hidden = response[1] & FeatureFlag::Hidden;
     info.obsolete = response[1] & FeatureFlag::Obsolete;
     info.internal = response[1] & FeatureFlag::Internal;
 
     return info;
+}
+
+std::tuple<uint8_t, uint8_t> Root::getVersion()
+{
+    std::vector<uint8_t> params(0);
+    auto response = this->callFunction(Function::Ping, params);
+
+    return std::make_tuple(response[0], response[1]);
 }

src/logid/backend/hidpp20/features/Root.h

@@ -23,7 +23,7 @@ namespace hidpp20
         Root(Device* device);
 
         feature_info getFeature (uint16_t feature_id);
-        void ping();
+        std::tuple<uint8_t, uint8_t> getVersion();
     private:
         enum FeatureFlag : uint8_t
         {