Callback support for unbound reference and array arguments.

base/bind_internal.h.pump

 $$ This is a pump file for generating file templates.  Pump is a python
 $$ script that is part of the Google Test suite of utilities.  Description
 $$ can be found here:
 $$
 $$ http://code.google.com/p/googletest/wiki/PumpManual
 $$
 
 $var MAX_ARITY = 6
 
 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
@@ skipping 64 matching lines @@
 $range ARITY 0..MAX_ARITY
 $for ARITY [[
 $range ARG 1..ARITY
 
 // Function: Arity $(ARITY).
 template <typename R[[]]
 $if ARITY > 0[[, ]] $for ARG , [[typename X$(ARG)]]>
 struct FunctionTraits<R(*)($for ARG , [[X$(ARG)]])> {
   typedef R (*NormalizedSig)($for ARG , [[X$(ARG)]]);
   typedef false_type IsMethod;
+
+$if ARITY > 0 [[
+
+  // Target type for each bound parameter.
+
+$for ARG [[
+  typedef X$(ARG) B$(ARG);
+
+]]  $$ for ARG
+]]  $$ if ARITY > 0
+
 };
 
 // Method: Arity $(ARITY).
 template <typename R, typename T[[]]
 $if ARITY > 0[[, ]] $for ARG , [[typename X$(ARG)]]>
 struct FunctionTraits<R(T::*)($for ARG , [[X$(ARG)]])> {
   typedef R (T::*NormalizedSig)($for ARG , [[X$(ARG)]]);
   typedef true_type IsMethod;
+
+  // Target type for each bound parameter.
+  typedef T B1;
+
+$for ARG [[
+  typedef X$(ARG) B$(ARG + 1);
+
+]]  $$ for ARG
+
 };
 
 // Const Method: Arity $(ARITY).
 template <typename R, typename T[[]]
 $if ARITY > 0[[, ]] $for ARG , [[typename X$(ARG)]]>
 struct FunctionTraits<R(T::*)($for ARG , [[X$(ARG)]]) const> {
   typedef R (T::*NormalizedSig)($for ARG , [[X$(ARG)]]);
   typedef true_type IsMethod;
+
+  // Target type for each bound parameter.
+  typedef T B1;
+
+$for ARG [[
+  typedef X$(ARG) B$(ARG + 1);
+
+]]  $$ for ARG
+
 };
 
 ]]  $$for ARITY
 
 // InvokerN<>
 //
 // The InvokerN templates contain a static DoInvoke() function that is the key
 // to implementing type erasure in the Callback() classes.
 //
 // DoInvoke() is a static function with a fixed signature that is independent
@@ skipping 33 matching lines @@
 $var M_ARITY = ARITY - 1
 $range M_ARG 1..M_ARITY
 $range M_BOUND_ARG 2..BOUND
 $range M_UNBOUND_ARG (M_ARITY - UNBOUND + 1)..M_ARITY
 
 // Function: Arity $(ARITY) -> $(UNBOUND).
 template <typename StorageType, typename R[[]]
 $if ARITY > 0 [[,]][[]]
 $for ARG , [[typename X$(ARG)]]>
 struct Invoker$(BOUND)<StorageType, R(*)($for ARG , [[X$(ARG)]])> {
-$if ARITY > 0 [[
-
-  COMPILE_ASSERT(
-      !($for ARG || [[ is_non_const_reference<X$(ARG)>::value ]]),
-      do_not_bind_functions_with_nonconst_ref);
-
-]]
-
   static R DoInvoke(InvokerStorageBase* base[[]]
 $if UNBOUND != 0 [[, ]][[]]
-$for UNBOUND_ARG , [[const X$(UNBOUND_ARG)& x$(UNBOUND_ARG)]]) {
+$for UNBOUND_ARG , [[typename internal::ParamTraits<X$(UNBOUND_ARG)>::ForwardType x$(UNBOUND_ARG)]]) {
     StorageType* invoker = static_cast<StorageType*>(base);
     return invoker->f_($for BOUND_ARG , [[Unwrap(invoker->p$(BOUND_ARG)_)]][[]]
 $$ Add comma if there are both boudn and unbound args.
 $if UNBOUND > 0 [[$if BOUND > 0 [[, ]]]][[]]
 $for UNBOUND_ARG , [[x$(UNBOUND_ARG)]]);
   }
 };
 
 $if BOUND > 0 [[
 
 // Method: Arity $(M_ARITY) -> $(UNBOUND).
 template <typename StorageType, typename R, typename T[[]]
 $if M_ARITY > 0[[, ]] $for M_ARG , [[typename X$(M_ARG)]]>
 struct Invoker$(BOUND)<StorageType, R(T::*)($for M_ARG , [[X$(M_ARG)]])> {
-$if M_ARITY > 0 [[
-
-  COMPILE_ASSERT(
-      !($for M_ARG || [[ is_non_const_reference<X$(M_ARG)>::value ]]),
-      do_not_bind_functions_with_nonconst_ref);
-
-]]
-
   static R DoInvoke(InvokerStorageBase* base[[]]
 $if UNBOUND > 0 [[, ]][[]]
-$for M_UNBOUND_ARG , [[const X$(M_UNBOUND_ARG)& x$(M_UNBOUND_ARG)]]) {
+$for M_UNBOUND_ARG , [[typename internal::ParamTraits<X$(M_UNBOUND_ARG)>::ForwardType x$(M_UNBOUND_ARG)]]) {
     StorageType* invoker = static_cast<StorageType*>(base);
     return (Unwrap(invoker->p1_)->*invoker->f_)([[]]
 $for M_BOUND_ARG , [[Unwrap(invoker->p$(M_BOUND_ARG)_)]][[]]
 $if UNBOUND > 0 [[$if BOUND > 1 [[, ]]]][[]]
 $for M_UNBOUND_ARG , [[x$(M_UNBOUND_ARG)]]);
   }
 };
 
 ]]  $$ if BOUND
 
@@ skipping 21 matching lines @@
 
 template <typename Sig[[]]
 $if BOUND > 0 [[, ]]
 $for BOUND_ARG , [[typename P$(BOUND_ARG)]]>
 class InvokerStorage$(BOUND) : public InvokerStorageBase {
  public:
   typedef InvokerStorage$(BOUND) StorageType;
   typedef FunctionTraits<Sig> TargetTraits;
   typedef Invoker$(BOUND)<StorageType, typename TargetTraits::NormalizedSig> Invoker;
   typedef typename TargetTraits::IsMethod IsMethod;
+
 $for BOUND_ARG [[
 $if BOUND_ARG == 1 [[
 
   // For methods, we need to be careful for parameter 1.  We skip the
   // scoped_refptr check because the binder itself takes care of this. We also
   // disallow binding of an array as the method's target object.
   COMPILE_ASSERT(IsMethod::value ||
                  !internal::UnsafeBindtoRefCountedArg<P$(BOUND_ARG)>::value,
                  p$(BOUND_ARG)_is_refcounted_type_and_needs_scoped_refptr);
   COMPILE_ASSERT(!IsMethod::value || !is_array<P$(BOUND_ARG)>::value,
                  first_bound_argument_to_method_cannot_be_array);
 ]] $else [[
 
   COMPILE_ASSERT(!internal::UnsafeBindtoRefCountedArg<P$(BOUND_ARG)>::value,
                  p$(BOUND_ARG)_is_refcounted_type_and_needs_scoped_refptr);
 ]]  $$ $if BOUND_ARG
 ]]  $$ $for BOUND_ARG
 
 
+$if BOUND > 0 [[
+
+  // Do not allow binding a non-const reference parameter. Non-const reference
+  // parameters are disallowed by the Google style guide.  Also, binding a
+  // non-const reference parameter can make for subtle bugs because the
+  // invoked function will receive a reference to the stored copy of the
+  // argument and not the original.
+  COMPILE_ASSERT(
+      !($for BOUND_ARG || [[ is_non_const_reference<typename TargetTraits::B$(BOUND_ARG)>::value ]]),
+      do_not_bind_functions_with_nonconst_ref);
+
+]]
+
 
   InvokerStorage$(BOUND)(Sig f
 $if BOUND > 0 [[, ]]
 $for BOUND_ARG , [[const P$(BOUND_ARG)& p$(BOUND_ARG)]])
       : f_(f)[[]]
 $if BOUND == 0 [[
  {
 
 ]] $else [[
-, $for BOUND_ARG , [[p$(BOUND_ARG)_(static_cast<typename BindType<P$(BOUND_ARG)>::StorageType>(p$(BOUND_ARG)))]] {
+, $for BOUND_ARG , [[p$(BOUND_ARG)_(static_cast<typename ParamTraits<P$(BOUND_ARG)>::StorageType>(p$(BOUND_ARG)))]] {
     MaybeRefcount<IsMethod, P1>::AddRef(p1_);
 
 ]]
   }
 
   virtual ~InvokerStorage$(BOUND)() {
 $if BOUND > 0 [[
 
     MaybeRefcount<IsMethod, P1>::Release(p1_);
 
 ]]
   }
 
   Sig f_;
 
 $for BOUND_ARG [[
-  typename BindType<P$(BOUND_ARG)>::StorageType p$(BOUND_ARG)_;
+  typename ParamTraits<P$(BOUND_ARG)>::StorageType p$(BOUND_ARG)_;
 
 ]]
 };
 
 ]]  $$ for BOUND
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_BIND_INTERNAL_H_