Merge pull request #285 from ipa-mdl/fix/interface-composition

Interface composition revised

hardware_interface/include/hardware_interface/internal/interface_manager.h

@@ -43,27 +43,16 @@
 
 namespace hardware_interface
 {
+
+namespace internal
+{
+
 // SFINAE workaround, so that we have reflection inside the template functions
 template <typename T>
 struct CheckIsResourceManager {
-  // variable definitions for compiler-time logic
-  typedef char yes[1];
-  typedef char no[2];
-
-  // method called if C is a ResourceManager
-  template <typename C>
-  static yes& testRM(typename C::resource_manager_type*);
-
-  // method called if C is not a ResourceManager
-  template <typename>
-  static no& testRM(...);
-
-  // CheckIsResourceManager<T>::value == true when T is a ResourceManager
-  static const bool value = (sizeof(testRM<T>(0)) == sizeof(yes));
-
   // method called if C is a ResourceManager
   template <typename C>
-  static yes& callCM(typename std::vector<C*>& managers, C* result, typename C::resource_manager_type*)
+  static void callCM(typename std::vector<C*>& managers, C* result, typename C::resource_manager_type*)
   {
     std::vector<typename C::resource_manager_type*> managers_in;
     // we have to typecase back to base class
@@ -74,7 +63,7 @@ struct CheckIsResourceManager {
 
   // method called if C is not a ResourceManager
   template <typename C>
-  static no& callCM(typename std::vector<C*>& managers, C* result, ...) {}
+  static void callCM(typename std::vector<C*>& managers, C* result, ...) {}
 
   // calls ResourceManager::concatManagers if C is a ResourceManager
   static const void callConcatManagers(typename std::vector<T*>& managers, T* result)
@@ -83,20 +72,47 @@ struct CheckIsResourceManager {
 
   // method called if C is a ResourceManager
   template <typename C>
-  static std::vector<std::string> callGR(C* iface, typename C::resource_manager_type*)
+  static void callGR(std::vector<std::string> &resources, C* iface, typename C::resource_manager_type*)
   {
-    return iface->getNames();
+    resources = iface->getNames();
   }
 
   // method called if C is not a ResourceManager
   template <typename C>
-  static std::vector<std::string> callGR(T* iface, ...) {}
+  static void callGR(std::vector<std::string> &resources, T* iface, ...) { }
 
   // calls ResourceManager::concatManagers if C is a ResourceManager
-  static std::vector<std::string> callGetResources(T* iface)
-  { return callGR<T>(iface, 0); }
+  static void callGetResources(std::vector<std::string> &resources, T* iface)
+  { return callGR<T>(resources, iface, 0); }
+
+  template <typename C>
+  static T* newCI(boost::ptr_vector<ResourceManagerBase> &guards, typename C::resource_manager_type*)
+  {
+    T* iface_combo = new T;
+    // save the new interface pointer to allow for its correct destruction
+    guards.push_back(static_cast<ResourceManagerBase*>(iface_combo));
+    return iface_combo;
+  }
+
+  // method called if C is not a ResourceManager
+  template <typename C>
+  static T* newCI(boost::ptr_vector<ResourceManagerBase> &guards, ...) {
+    // it is not a ResourceManager
+    ROS_ERROR("You cannot register multiple interfaces of the same type which are "
+              "not of type ResourceManager. There is no established protocol "
+              "for combining them.");
+    return NULL;
+  }
+
+  static T* newCombinedInterface(boost::ptr_vector<ResourceManagerBase> &guards)
+  {
+    return newCI<T>(guards, 0);
+  }
+
 };
 
+} // namespace internal
+
 class InterfaceManager
 {
 public:
@@ -118,14 +134,7 @@ class InterfaceManager
       ROS_WARN_STREAM("Replacing previously registered interface '" << iface_name << "'.");
     }
     interfaces_[iface_name] = iface;
-
-    std::vector<std::string> resources;
-    if(CheckIsResourceManager<T>::value)
-    {
-      // it is a ResourceManager. Get the names of the resources
-      resources = CheckIsResourceManager<T>::callGetResources(iface);
-    }
-    resources_[iface_name] = resources;
+    internal::CheckIsResourceManager<T>::callGetResources(resources_[iface_name], iface);
   }
 
   void registerInterfaceManager(InterfaceManager* iface_man)
@@ -187,15 +196,10 @@ class InterfaceManager
       iface_combo = static_cast<T*>(it_combo->second);
     } else {
       // no existing combined interface
-      if(CheckIsResourceManager<T>::value) {
-        // it is a ResourceManager
-
-        // create a new combined interface
-        iface_combo = new T;
-        // save the new interface pointer to allow for its correct destruction
-        interface_destruction_list_.push_back(reinterpret_cast<ResourceManagerBase*>(iface_combo));
+      iface_combo = internal::CheckIsResourceManager<T>::newCombinedInterface(interface_destruction_list_);
+      if(iface_combo) {
         // concat all of the resource managers together
-        CheckIsResourceManager<T>::callConcatManagers(iface_list, iface_combo);
+        internal::CheckIsResourceManager<T>::callConcatManagers(iface_list, iface_combo);
         // save the combined interface for if this is called again
         interfaces_combo_[type_name] = iface_combo;
         num_ifaces_registered_[type_name] = iface_list.size();

hardware_interface/test/interface_manager_test.cpp

@@ -34,6 +34,7 @@ using namespace hardware_interface;
 
 struct FooInterface
 {
+  FooInterface(int foo): foo(foo) {}
   int foo;
 };
 
@@ -50,7 +51,7 @@ struct BazInterface
 TEST(InterfaceManagerTest, InterfaceRegistration)
 {
   // Register interfaces
-  FooInterface foo_iface;
+  FooInterface foo_iface(0);
   BarInterface bar_iface;
 
   InterfaceManager iface_mgr;
@@ -66,11 +67,8 @@ TEST(InterfaceManagerTest, InterfaceRegistration)
 TEST(InterfaceManagerTest, InterfaceRewriting)
 {
   // Two instances of the same interface
-  FooInterface foo_iface_1;
-  foo_iface_1.foo = 1;
-
-  FooInterface foo_iface_2;
-  foo_iface_2.foo = 2;
+  FooInterface foo_iface_1(1);
+  FooInterface foo_iface_2(2);
 
   // Register first interface and validate it
   InterfaceManager iface_mgr;
@@ -91,4 +89,3 @@ int main(int argc, char** argv)
   testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }
-