changed functions with optional std::string parameters from "std::string const &" to "vk::Optional<std::string const> const &";

moved vk::Optional constructor on std::nullptr_t from private to public;
introduced vk::Optional::operator->() and explicit operator bool();
removed static operator null() on all struct-wrapper classes

README.md

@@ -106,8 +106,8 @@ vk::ImageCreateInfo ci(
 # String conversions
 
 At development time it can be quite handy to have a utility function that can convert an enum or flags to a string for debugging purposes. To achieve this,
-we have implemented ```getString(type)``` functions for all enums and flags. Calling ```getString(vk::SharingMode::eExclusive)``` will return 'Exclusive' and calling
-```getString(vk::QueueFlagBits::eGraphics | vk::QueueFlagBits::eCompute)``` will return the concatenated string 'Graphics | Compute'.
+we have implemented ```to_string(type)``` functions for all enums and flags. Calling ```to_string(vk::SharingMode::eExclusive)``` will return 'Exclusive' and calling
+```to_string(vk::QueueFlagBits::eGraphics | vk::QueueFlagBits::eCompute)``` will return the concatenated string 'Graphics | Compute'.
 
 # Alternative Initialization of Structs
 
@@ -141,7 +141,7 @@ parameter matches the handle. In addition to this we made a few changes to the s
 * ```const char *``` has been replaced by ```std::string ```
 * ```T const*``` has been replaced by ```T const &``` to allow temporary objects. This is useful to pass small structures like ```vk::ClearColorValue``` or ```vk::Extent*```
 ```commandBuffer.clearColorImage(image, layout, std::array<float, 4>{1.0f, 1.0f, 1.0f, 1.0f}, {...});```
-Optional parameters are being replaced by ```Optional<T> const &``` which accept a type of ```T const&```. To tell the wrapper that a nullptr should be passed use ```T::null()```.
+Optional parameters are being replaced by ```Optional<T> const &``` which accept a type of ```T const&```. ```nullptr``` can be used to initialize an empty ```Optional<T>```.
 * The wrapper will throw a ```std::system_error``` if a ```vk::Result``` return value is not an success code. If there's only a single success code it's not returned at all. In this case functions with a single output value do return this output value instead.
 
 Here are a few code examples:
@@ -168,8 +168,8 @@ Here are a few code examples:
     // Accept std::vector as source for updateBuffer
     commandBuffer.updateBuffer(buffer, 0, {some values}); // update buffer with std::vector
 
-    // Sometimes it's necessary to pass a nullptr to a struct. For this case we've added Optional<T> T::null() to all structs T as replacement for the nullptr.
-    device.allocateMemory(allocateInfo, vk::AllocationCallbacks::null());
+    // Sometimes it's necessary to pass a nullptr to a struct. For this case we've added Optional<T>(std::nullptr_t).
+    device.allocateMemory(allocateInfo, nullptr);
 
   }
   catch (std::system_error e)

VkCppGenerator.cpp

@@ -215,20 +215,21 @@ const std::string flagsHeader(
 );
 
 std::string const optionalClassHeader = (
-"  template <typename RefType>\n"
-"  class Optional\n"
-"  {\n"
-"  public:\n"
-"    Optional(RefType & reference) { m_ptr = &reference; }\n"
-"\n"
-"    operator RefType*() const { return m_ptr; }\n"
-"\n"
-"  private:\n"
-"    Optional(std::nullptr_t) { m_ptr = nullptr; }\n"
-"    friend RefType;\n"
-"    RefType *m_ptr;\n"
-"  };\n"
-"\n"
+  "  template <typename RefType>\n"
+  "  class Optional\n"
+  "  {\n"
+  "  public:\n"
+  "    Optional(RefType & reference) { m_ptr = &reference; }\n"
+  "    Optional(std::nullptr_t) { m_ptr = nullptr; }\n"
+  "\n"
+  "    operator RefType*() const { return m_ptr; }\n"
+  "    RefType const* operator->() const { return m_ptr; }\n"
+  "    explicit operator bool() const { return !m_ptr; }\n"
+  "\n"
+  "  private:\n"
+  "    RefType *m_ptr;\n"
+  "  };\n"
+  "\n"
 );
 
 // trim from end
@@ -1603,7 +1604,15 @@ void writeCall(std::ofstream & ofs, std::string const& name, size_t templateInde
           }
           else if (commandData.arguments[it->first].pureType == "char")
           {
-            ofs << reduceName(commandData.arguments[it->first].name) << ".c_str()";
+            ofs << reduceName(commandData.arguments[it->first].name);
+            if (commandData.arguments[it->first].optional)
+            {
+              ofs << " ? " << reduceName(commandData.arguments[it->first].name) << "->c_str() : nullptr";
+            }
+            else
+            {
+              ofs << ".c_str()";
+            }
           }
           else
           {
@@ -1626,11 +1635,11 @@ void writeCall(std::ofstream & ofs, std::string const& name, size_t templateInde
             {
               ofs << "&";
             }
-            ofs << reduceName(commandData.arguments[i].name)
-                << (commandData.arguments[i].optional ? "))" : " )");
+            ofs << reduceName(commandData.arguments[i].name) << (commandData.arguments[i].optional ? "))" : " )");
           }
           else
           {
+            assert(!commandData.arguments[i].optional);
             ofs << "reinterpret_cast<Vk" << commandData.arguments[i].pureType << "*>( &" << reduceName(commandData.arguments[i].name) << " )";
           }
         }
@@ -1646,7 +1655,15 @@ void writeCall(std::ofstream & ofs, std::string const& name, size_t templateInde
           if (commandData.arguments[i].type.find("const") != std::string::npos)
           {
             assert(commandData.arguments[i].type.find("char") != std::string::npos);
-            ofs << reduceName(commandData.arguments[i].name) << ".c_str()";
+            ofs << reduceName(commandData.arguments[i].name);
+            if (commandData.arguments[i].optional)
+            {
+              ofs << " ? " << reduceName(commandData.arguments[i].name) << "->c_str() : nullptr";
+            }
+            else
+            {
+              ofs << ".c_str()";
+            }
           }
           else
           {
@@ -1864,10 +1881,10 @@ void writeFunctionHeader(std::ofstream & ofs, std::string const& indentation, st
       {
         ofs << ", ";
       }
-      if (vectorParameters.find(i) == vectorParameters.end())
-      {
+
+      std::map<size_t,size_t>::const_iterator it = vectorParameters.find(i);
       size_t pos = commandData.arguments[i].type.find('*');
-        if (pos == std::string::npos)
+      if ((it == vectorParameters.end()) && (pos == std::string::npos))
       {
         ofs << commandData.arguments[i].type << " " << commandData.arguments[i].name;
         if (!commandData.arguments[i].arraySize.empty())
@@ -1877,50 +1894,52 @@ void writeFunctionHeader(std::ofstream & ofs, std::string const& indentation, st
       }
       else
       {
-          std::string type = commandData.arguments[i].type;
-          if (type.find("char") != std::string::npos)
+        bool optional = commandData.arguments[i].optional && ((it == vectorParameters.end()) || (it->second == ~0));
+        if (optional)
         {
-            type = "std::string const&";
+          ofs << "vk::Optional<";
+        }
+        if (vectorParameters.find(i) == vectorParameters.end())
+        {
+          assert(pos != std::string::npos);
+          if (commandData.arguments[i].type.find("char") != std::string::npos)
+          {
+            ofs << "std::string const";
           }
           else
           {
-            assert(type[pos] == '*');
-            if (commandData.arguments[i].optional)
-            {
-              type[pos] = ' ';
-              type = "vk::Optional<" + trimEnd(type) + "> const &";
-            }
-            else
-            {
-              type[pos] = '&';
-            }
-          }
-          ofs << type << " " << reduceName(commandData.arguments[i].name);
+            assert(commandData.arguments[i].type[pos] == '*');
+            ofs << trimEnd(commandData.arguments[i].type.substr(0, pos));
           }
         }
         else
         {
           if (templateIndex == i)
           {
-          ofs << "std::vector<T> ";
+            ofs << "std::vector<T>";
           }
           else if (commandData.arguments[i].pureType == "char")
           {
-          ofs << "std::string ";
+            ofs << "std::string";
           }
           else if (commandData.arguments[i].pureType == "void")
           {
-          ofs << "std::vector<uint8_t> ";
+            ofs << "std::vector<uint8_t>";
           }
           else
           {
-          ofs << "std::vector<" << commandData.arguments[i].pureType << "> ";
+            ofs << "std::vector<" << commandData.arguments[i].pureType << ">";
           }
           if (commandData.arguments[i].type.find("const") != std::string::npos)
           {
-          ofs << "const";
+            ofs << " const";
           }
-        ofs << "& " << reduceName(commandData.arguments[i].name);
+        }
+        if (optional)
+        {
+          ofs << "> const";
+        }
+        ofs << " & " << reduceName(commandData.arguments[i].name);
       }
       argEncountered = true;
     }
@@ -2506,13 +2525,6 @@ void writeTypeStruct( std::ofstream & ofs, VkData const& vkData, DependencyData
     }
   }
 
-  // null handle
-  ofs << "    static Optional<const " << dependencyData.name << "> null()" << std::endl
-      << "    {" << std::endl
-      << "      return Optional<const " << dependencyData.name << ">(nullptr);" << std::endl
-      << "    }" << std::endl
-      << std::endl;
-
   // the cast-operator to the wrapped struct, and the struct itself as a private member variable
   ofs << "    operator const Vk" << dependencyData.name << "&() const" << std::endl
       << "    {" << std::endl