Improved function call performance

CHANGES.md

@@ -24,6 +24,7 @@ Features
 * [#350](https://github.com/twall/jna/pull/350): Added `jnacontrib.x11.api.X.Window.getSubwindows` - [@rm5248](https://github.com/rm5248).
 * Improved `contrib/msoffice` sample - [@wolftobias](https://github.com/wolftobias).
 * [#352](https://github.com/twall/jna/pull/352): Performance improvements due to reduced locking in `com.sun.jna.Library$Handler` and fewer vararg checks in `com.sun.jna.Function` - [@Boereck](https://github.com/Boereck).
+* [#353](https://github.com/twall/jna/pull/353): Performance improvements by improved collaboration between `com.sun.jna.Library$Handler` and `com.sun.jna.Function` - [@Boereck](https://github.com/Boereck).
 * [#357](https://github.com/twall/jna/pull/357): Added `com.sun.jna.platform.win32.Kernel32.SetSystemTime` - [@lgoldstein](https://github.com/lgoldstein), [@thomasjoulin](https://github.com/thomasjoulin).
 * [#365](https://github.com/twall/jna/pull/365): Added `com.sun.jna.platform.win32.Kernel32.GetComputerNameEx` support - [@lgoldstein](https://github.com/lgoldstein).
 * [#368](https://github.com/twall/jna/pull/368): Added `com.sun.jna.platform.win32.Kernel32.VirtualQueryEx`, `com.sun.jna.platform.win32.WinNT.MEMORY_BASIC_INFORMATION` and `MEM_COMMIT`, `MEM_FREE`, `MEM_RESERVE`, `MEM_IMAGE`, `MEM_MAPPED`, `MEM_PRIVATE` constants - [@apsk](https://github.com/apsk).

src/com/sun/jna/Function.java

@@ -272,6 +272,17 @@ public Object invoke(Class returnType, Object[] inArgs) {
      * native result as an Object.
      */
     public Object invoke(Class returnType, Object[] inArgs, Map options) {
+        Method invokingMethod = (Method)options.get(OPTION_INVOKING_METHOD);
+        Class[] paramTypes = invokingMethod != null ? invokingMethod.getParameterTypes() : null;
+        return invoke(invokingMethod, paramTypes, returnType, inArgs, options);
+    }
+
+    /** Invoke the native function with the given arguments, returning the
+     * native result as an Object. This method can be called if invoking method and parameter
+     * types are already at hand. When calling {@link Function#invoke(Class, Object[], Map)},
+     * the method has to be in the options under key {@link Function#OPTION_INVOKING_METHOD}.
+     */
+    Object invoke(Method invokingMethod, Class[] paramTypes, Class returnType, Object[] inArgs, Map options) {
         // Clone the argument array to obtain a scratch space for modified
         // types/values
         Object[] args = { };
@@ -285,8 +296,6 @@ public Object invoke(Class returnType, Object[] inArgs, Map options) {
 
         TypeMapper mapper = 
             (TypeMapper)options.get(Library.OPTION_TYPE_MAPPER);
-        Method invokingMethod = (Method)options.get(OPTION_INVOKING_METHOD);
-        Class[] paramTypes = invokingMethod != null ? invokingMethod.getParameterTypes() : null;
         boolean allowObjects = Boolean.TRUE.equals(options.get(Library.OPTION_ALLOW_OBJECTS));
         boolean isVarArgs = args.length > 0 && invokingMethod != null ? isVarArgs(invokingMethod) : false;
         for (int i=0; i < args.length; i++) {

src/com/sun/jna/Library.java

@@ -167,18 +167,20 @@ public Class getInterfaceClass() {
          */
         private static final class FunctionInfo {
 
-            FunctionInfo(InvocationHandler handler, Function function, boolean isVarArgs, Map options) {
+            FunctionInfo(InvocationHandler handler, Function function, Class[] parameterTypes, boolean isVarArgs, Map options) {
                 super();
                 this.handler = handler;
                 this.function = function;
                 this.isVarArgs = isVarArgs;
                 this.options = options;
+                this.parameterTypes = parameterTypes;
             }
 
             final InvocationHandler handler;
             final Function function;
             final boolean isVarArgs;
             final Map options;
+            final Class[] parameterTypes;
         }
 
         public Object invoke(Object proxy, Method method, Object[] inArgs)
@@ -211,14 +213,16 @@ else if (OBJECT_EQUALS.equals(method)) {
                             handler = invocationMapper.getInvocationHandler(nativeLibrary, method);
                         }
                         Function function = null;
+                        Class[] parameterTypes = null;
                         Map options = null;
                         if (handler == null) {
                             // Find the function to invoke
                             function = nativeLibrary.getFunction(method.getName(), method);
+                            parameterTypes = method.getParameterTypes();
                             options = new HashMap(this.options);
                             options.put(Function.OPTION_INVOKING_METHOD, method);
                         }
-                        f = new FunctionInfo(handler, function, isVarArgs, options);
+                        f = new FunctionInfo(handler, function, parameterTypes, isVarArgs, options);
                         functions.put(method, f);
                     }
                 }
@@ -229,7 +233,7 @@ else if (OBJECT_EQUALS.equals(method)) {
             if (f.handler != null) {
                 return f.handler.invoke(proxy, method, inArgs);
             }
-            return f.function.invoke(method.getReturnType(), inArgs, f.options);
+            return f.function.invoke(method, f.parameterTypes, method.getReturnType(), inArgs, f.options);
         }
     }
 }