// This file was GENERATED by command: // pump.py callback.h.pump // DO NOT EDIT BY HAND!!! // Copyright (c) 2012 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef BASE_CALLBACK_H_ #define BASE_CALLBACK_H_ #include "base/callback_forward.h" #include "base/callback_internal.h" #include "base/template_util.h" // NOTE: Header files that do not require the full definition of Callback or // Closure should #include "base/callback_forward.h" instead of this file. // ----------------------------------------------------------------------------- // Introduction // ----------------------------------------------------------------------------- // // The templated Callback class is a generalized function object. Together // with the Bind() function in bind.h, they provide a type-safe method for // performing partial application of functions. // // Partial application (or "currying") is the process of binding a subset of // a function's arguments to produce another function that takes fewer // arguments. This can be used to pass around a unit of delayed execution, // much like lexical closures are used in other languages. For example, it // is used in Chromium code to schedule tasks on different MessageLoops. // // A callback with no unbound input parameters (base::Callback<void(void)>) // is called a base::Closure. Note that this is NOT the same as what other // languages refer to as a closure -- it does not retain a reference to its // enclosing environment. // // MEMORY MANAGEMENT AND PASSING // // The Callback objects themselves should be passed by const-reference, and // stored by copy. They internally store their state via a refcounted class // and thus do not need to be deleted. // // The reason to pass via a const-reference is to avoid unnecessary // AddRef/Release pairs to the internal state. // // // ----------------------------------------------------------------------------- // Quick reference for basic stuff // ----------------------------------------------------------------------------- // // BINDING A BARE FUNCTION // // int Return5() { return 5; } // base::Callback<int(void)> func_cb = base::Bind(&Return5); // LOG(INFO) << func_cb.Run(); // Prints 5. // // BINDING A CLASS METHOD // // The first argument to bind is the member function to call, the second is // the object on which to call it. // // class Ref : public base::RefCountedThreadSafe<Ref> { // public: // int Foo() { return 3; } // void PrintBye() { LOG(INFO) << "bye."; } // }; // scoped_refptr<Ref> ref = new Ref(); // base::Callback<void(void)> ref_cb = base::Bind(&Ref::Foo, ref); // LOG(INFO) << ref_cb.Run(); // Prints out 3. // // By default the object must support RefCounted or you will get a compiler // error. If you're passing between threads, be sure it's // RefCountedThreadSafe! See "Advanced binding of member functions" below if // you don't want to use reference counting. // // RUNNING A CALLBACK // // Callbacks can be run with their "Run" method, which has the same // signature as the template argument to the callback. // // void DoSomething(const base::Callback<void(int, std::string)>& callback) { // callback.Run(5, "hello"); // } // // Callbacks can be run more than once (they don't get deleted or marked when // run). However, this precludes using base::Passed (see below). // // void DoSomething(const base::Callback<double(double)>& callback) { // double myresult = callback.Run(3.14159); // myresult += callback.Run(2.71828); // } // // PASSING UNBOUND INPUT PARAMETERS // // Unbound parameters are specified at the time a callback is Run(). They are // specified in the Callback template type: // // void MyFunc(int i, const std::string& str) {} // base::Callback<void(int, const std::string&)> cb = base::Bind(&MyFunc); // cb.Run(23, "hello, world"); // // PASSING BOUND INPUT PARAMETERS // // Bound parameters are specified when you create thee callback as arguments // to Bind(). They will be passed to the function and the Run()ner of the // callback doesn't see those values or even know that the function it's // calling. // // void MyFunc(int i, const std::string& str) {} // base::Callback<void(void)> cb = base::Bind(&MyFunc, 23, "hello world"); // cb.Run(); // // A callback with no unbound input parameters (base::Callback<void(void)>) // is called a base::Closure. So we could have also written: // // base::Closure cb = base::Bind(&MyFunc, 23, "hello world"); // // When calling member functions, bound parameters just go after the object // pointer. // // base::Closure cb = base::Bind(&MyClass::MyFunc, this, 23, "hello world"); // // PARTIAL BINDING OF PARAMETERS // // You can specify some parameters when you create the callback, and specify // the rest when you execute the callback. // // void MyFunc(int i, const std::string& str) {} // base::Callback<void(const std::string&)> cb = base::Bind(&MyFunc, 23); // cb.Run("hello world"); // // When calling a function bound parameters are first, followed by unbound // parameters. // // // ----------------------------------------------------------------------------- // Quick reference for advanced binding // ----------------------------------------------------------------------------- // // BINDING A CLASS METHOD WITH WEAK POINTERS // // base::Bind(&MyClass::Foo, GetWeakPtr()); // // The callback will not be issued if the object is destroyed at the time // it's issued. DANGER: weak pointers are not threadsafe, so don't use this // when passing between threads! // // BINDING A CLASS METHOD WITH MANUAL LIFETIME MANAGEMENT // // base::Bind(&MyClass::Foo, base::Unretained(this)); // // This disables all lifetime management on the object. You're responsible // for making sure the object is alive at the time of the call. You break it, // you own it! // // BINDING A CLASS METHOD AND HAVING THE CALLBACK OWN THE CLASS // // MyClass* myclass = new MyClass; // base::Bind(&MyClass::Foo, base::Owned(myclass)); // // The object will be deleted when the callback is destroyed, even if it's // not run (like if you post a task during shutdown). Potentially useful for // "fire and forget" cases. // // IGNORING RETURN VALUES // // Sometimes you want to call a function that returns a value in a callback // that doesn't expect a return value. // // int DoSomething(int arg) { cout << arg << endl; } // base::Callback<void<int>) cb = // base::Bind(base::IgnoreResult(&DoSomething)); // // // ----------------------------------------------------------------------------- // Quick reference for binding parameters to Bind() // ----------------------------------------------------------------------------- // // Bound parameters are specified as arguments to Bind() and are passed to the // function. A callback with no parameters or no unbound parameters is called a // Closure (base::Callback<void(void)> and base::Closure are the same thing). // // PASSING PARAMETERS OWNED BY THE CALLBACK // // void Foo(int* arg) { cout << *arg << endl; } // int* pn = new int(1); // base::Closure foo_callback = base::Bind(&foo, base::Owned(pn)); // // The parameter will be deleted when the callback is destroyed, even if it's // not run (like if you post a task during shutdown). // // PASSING PARAMETERS AS A scoped_ptr // // void TakesOwnership(scoped_ptr<Foo> arg) {} // scoped_ptr<Foo> f(new Foo); // // f becomes null during the following call. // base::Closure cb = base::Bind(&TakesOwnership, base::Passed(&f)); // // Ownership of the parameter will be with the callback until the it is run, // when ownership is passed to the callback function. This means the callback // can only be run once. If the callback is never run, it will delete the // object when it's destroyed. // // PASSING PARAMETERS AS A scoped_refptr // // void TakesOneRef(scoped_refptr<Foo> arg) {} // scoped_refptr<Foo> f(new Foo) // base::Closure cb = base::Bind(&TakesOneRef, f); // // This should "just work." The closure will take a reference as long as it // is alive, and another reference will be taken for the called function. // // PASSING PARAMETERS BY REFERENCE // // Const references are *copied* unless ConstRef is used. Example: // // void foo(const int& arg) { printf("%d %p\n", arg, &arg); } // int n = 1; // base::Closure has_copy = base::Bind(&foo, n); // base::Closure has_ref = base::Bind(&foo, base::ConstRef(n)); // n = 2; // foo(n); // Prints "2 0xaaaaaaaaaaaa" // has_copy.Run(); // Prints "1 0xbbbbbbbbbbbb" // has_ref.Run(); // Prints "2 0xaaaaaaaaaaaa" // // Normally parameters are copied in the closure. DANGER: ConstRef stores a // const reference instead, referencing the original parameter. This means // that you must ensure the object outlives the callback! // // // ----------------------------------------------------------------------------- // Implementation notes // ----------------------------------------------------------------------------- // // WHERE IS THIS DESIGN FROM: // // The design Callback and Bind is heavily influenced by C++'s // tr1::function/tr1::bind, and by the "Google Callback" system used inside // Google. // // // HOW THE IMPLEMENTATION WORKS: // // There are three main components to the system: // 1) The Callback classes. // 2) The Bind() functions. // 3) The arguments wrappers (e.g., Unretained() and ConstRef()). // // The Callback classes represent a generic function pointer. Internally, // it stores a refcounted piece of state that represents the target function // and all its bound parameters. Each Callback specialization has a templated // constructor that takes an BindState<>*. In the context of the constructor, // the static type of this BindState<> pointer uniquely identifies the // function it is representing, all its bound parameters, and a Run() method // that is capable of invoking the target. // // Callback's constructor takes the BindState<>* that has the full static type // and erases the target function type as well as the types of the bound // parameters. It does this by storing a pointer to the specific Run() // function, and upcasting the state of BindState<>* to a // BindStateBase*. This is safe as long as this BindStateBase pointer // is only used with the stored Run() pointer. // // To BindState<> objects are created inside the Bind() functions. // These functions, along with a set of internal templates, are responsible for // // - Unwrapping the function signature into return type, and parameters // - Determining the number of parameters that are bound // - Creating the BindState storing the bound parameters // - Performing compile-time asserts to avoid error-prone behavior // - Returning an Callback<> with an arity matching the number of unbound // parameters and that knows the correct refcounting semantics for the // target object if we are binding a method. // // The Bind functions do the above using type-inference, and template // specializations. // // By default Bind() will store copies of all bound parameters, and attempt // to refcount a target object if the function being bound is a class method. // These copies are created even if the function takes parameters as const // references. (Binding to non-const references is forbidden, see bind.h.) // // To change this behavior, we introduce a set of argument wrappers // (e.g., Unretained(), and ConstRef()). These are simple container templates // that are passed by value, and wrap a pointer to argument. See the // file-level comment in base/bind_helpers.h for more info. // // These types are passed to the Unwrap() functions, and the MaybeRefcount() // functions respectively to modify the behavior of Bind(). The Unwrap() // and MaybeRefcount() functions change behavior by doing partial // specialization based on whether or not a parameter is a wrapper type. // // ConstRef() is similar to tr1::cref. Unretained() is specific to Chromium. // // // WHY NOT TR1 FUNCTION/BIND? // // Direct use of tr1::function and tr1::bind was considered, but ultimately // rejected because of the number of copy constructors invocations involved // in the binding of arguments during construction, and the forwarding of // arguments during invocation. These copies will no longer be an issue in // C++0x because C++0x will support rvalue reference allowing for the compiler // to avoid these copies. However, waiting for C++0x is not an option. // // Measured with valgrind on gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5), the // tr1::bind call itself will invoke a non-trivial copy constructor three times // for each bound parameter. Also, each when passing a tr1::function, each // bound argument will be copied again. // // In addition to the copies taken at binding and invocation, copying a // tr1::function causes a copy to be made of all the bound parameters and // state. // // Furthermore, in Chromium, it is desirable for the Callback to take a // reference on a target object when representing a class method call. This // is not supported by tr1. // // Lastly, tr1::function and tr1::bind has a more general and flexible API. // This includes things like argument reordering by use of // tr1::bind::placeholder, support for non-const reference parameters, and some // limited amount of subtyping of the tr1::function object (e.g., // tr1::function<int(int)> is convertible to tr1::function<void(int)>). // // These are not features that are required in Chromium. Some of them, such as // allowing for reference parameters, and subtyping of functions, may actually // become a source of errors. Removing support for these features actually // allows for a simpler implementation, and a terser Currying API. // // // WHY NOT GOOGLE CALLBACKS? // // The Google callback system also does not support refcounting. Furthermore, // its implementation has a number of strange edge cases with respect to type // conversion of its arguments. In particular, the argument's constness must // at times match exactly the function signature, or the type-inference might // break. Given the above, writing a custom solution was easier. // // // MISSING FUNCTIONALITY // - Invoking the return of Bind. Bind(&foo).Run() does not work; // - Binding arrays to functions that take a non-const pointer. // Example: // void Foo(const char* ptr); // void Bar(char* ptr); // Bind(&Foo, "test"); // Bind(&Bar, "test"); // This fails because ptr is not const. namespace base { // First, we forward declare the Callback class template. This informs the // compiler that the template only has 1 type parameter which is the function // signature that the Callback is representing. // // After this, create template specializations for 0-7 parameters. Note that // even though the template typelist grows, the specialization still // only has one type: the function signature. // // If you are thinking of forward declaring Callback in your own header file, // please include "base/callback_forward.h" instead. template <typename Sig> class Callback; namespace internal { template <typename Runnable, typename RunType, typename BoundArgsType> struct BindState; } // namespace internal template <typename R> class Callback<R(void)> : public internal::CallbackBase { public: typedef R(RunType)(); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run() const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get()); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*); }; template <typename R, typename A1> class Callback<R(A1)> : public internal::CallbackBase { public: typedef R(RunType)(A1); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1) const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get(), internal::CallbackForward(a1)); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*, typename internal::CallbackParamTraits<A1>::ForwardType); }; template <typename R, typename A1, typename A2> class Callback<R(A1, A2)> : public internal::CallbackBase { public: typedef R(RunType)(A1, A2); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1, typename internal::CallbackParamTraits<A2>::ForwardType a2) const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get(), internal::CallbackForward(a1), internal::CallbackForward(a2)); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*, typename internal::CallbackParamTraits<A1>::ForwardType, typename internal::CallbackParamTraits<A2>::ForwardType); }; template <typename R, typename A1, typename A2, typename A3> class Callback<R(A1, A2, A3)> : public internal::CallbackBase { public: typedef R(RunType)(A1, A2, A3); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1, typename internal::CallbackParamTraits<A2>::ForwardType a2, typename internal::CallbackParamTraits<A3>::ForwardType a3) const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get(), internal::CallbackForward(a1), internal::CallbackForward(a2), internal::CallbackForward(a3)); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*, typename internal::CallbackParamTraits<A1>::ForwardType, typename internal::CallbackParamTraits<A2>::ForwardType, typename internal::CallbackParamTraits<A3>::ForwardType); }; template <typename R, typename A1, typename A2, typename A3, typename A4> class Callback<R(A1, A2, A3, A4)> : public internal::CallbackBase { public: typedef R(RunType)(A1, A2, A3, A4); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1, typename internal::CallbackParamTraits<A2>::ForwardType a2, typename internal::CallbackParamTraits<A3>::ForwardType a3, typename internal::CallbackParamTraits<A4>::ForwardType a4) const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get(), internal::CallbackForward(a1), internal::CallbackForward(a2), internal::CallbackForward(a3), internal::CallbackForward(a4)); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*, typename internal::CallbackParamTraits<A1>::ForwardType, typename internal::CallbackParamTraits<A2>::ForwardType, typename internal::CallbackParamTraits<A3>::ForwardType, typename internal::CallbackParamTraits<A4>::ForwardType); }; template <typename R, typename A1, typename A2, typename A3, typename A4, typename A5> class Callback<R(A1, A2, A3, A4, A5)> : public internal::CallbackBase { public: typedef R(RunType)(A1, A2, A3, A4, A5); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1, typename internal::CallbackParamTraits<A2>::ForwardType a2, typename internal::CallbackParamTraits<A3>::ForwardType a3, typename internal::CallbackParamTraits<A4>::ForwardType a4, typename internal::CallbackParamTraits<A5>::ForwardType a5) const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get(), internal::CallbackForward(a1), internal::CallbackForward(a2), internal::CallbackForward(a3), internal::CallbackForward(a4), internal::CallbackForward(a5)); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*, typename internal::CallbackParamTraits<A1>::ForwardType, typename internal::CallbackParamTraits<A2>::ForwardType, typename internal::CallbackParamTraits<A3>::ForwardType, typename internal::CallbackParamTraits<A4>::ForwardType, typename internal::CallbackParamTraits<A5>::ForwardType); }; template <typename R, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6> class Callback<R(A1, A2, A3, A4, A5, A6)> : public internal::CallbackBase { public: typedef R(RunType)(A1, A2, A3, A4, A5, A6); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1, typename internal::CallbackParamTraits<A2>::ForwardType a2, typename internal::CallbackParamTraits<A3>::ForwardType a3, typename internal::CallbackParamTraits<A4>::ForwardType a4, typename internal::CallbackParamTraits<A5>::ForwardType a5, typename internal::CallbackParamTraits<A6>::ForwardType a6) const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get(), internal::CallbackForward(a1), internal::CallbackForward(a2), internal::CallbackForward(a3), internal::CallbackForward(a4), internal::CallbackForward(a5), internal::CallbackForward(a6)); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*, typename internal::CallbackParamTraits<A1>::ForwardType, typename internal::CallbackParamTraits<A2>::ForwardType, typename internal::CallbackParamTraits<A3>::ForwardType, typename internal::CallbackParamTraits<A4>::ForwardType, typename internal::CallbackParamTraits<A5>::ForwardType, typename internal::CallbackParamTraits<A6>::ForwardType); }; template <typename R, typename A1, typename A2, typename A3, typename A4, typename A5, typename A6, typename A7> class Callback<R(A1, A2, A3, A4, A5, A6, A7)> : public internal::CallbackBase { public: typedef R(RunType)(A1, A2, A3, A4, A5, A6, A7); Callback() : CallbackBase(NULL) { } // Note that this constructor CANNOT be explicit, and that Bind() CANNOT // return the exact Callback<> type. See base/bind.h for details. template <typename Runnable, typename BindRunType, typename BoundArgsType> Callback(internal::BindState<Runnable, BindRunType, BoundArgsType>* bind_state) : CallbackBase(bind_state) { // Force the assignment to a local variable of PolymorphicInvoke // so the compiler will typecheck that the passed in Run() method has // the correct type. PolymorphicInvoke invoke_func = &internal::BindState<Runnable, BindRunType, BoundArgsType> ::InvokerType::Run; polymorphic_invoke_ = reinterpret_cast<InvokeFuncStorage>(invoke_func); } bool Equals(const Callback& other) const { return CallbackBase::Equals(other); } R Run(typename internal::CallbackParamTraits<A1>::ForwardType a1, typename internal::CallbackParamTraits<A2>::ForwardType a2, typename internal::CallbackParamTraits<A3>::ForwardType a3, typename internal::CallbackParamTraits<A4>::ForwardType a4, typename internal::CallbackParamTraits<A5>::ForwardType a5, typename internal::CallbackParamTraits<A6>::ForwardType a6, typename internal::CallbackParamTraits<A7>::ForwardType a7) const { PolymorphicInvoke f = reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_); return f(bind_state_.get(), internal::CallbackForward(a1), internal::CallbackForward(a2), internal::CallbackForward(a3), internal::CallbackForward(a4), internal::CallbackForward(a5), internal::CallbackForward(a6), internal::CallbackForward(a7)); } private: typedef R(*PolymorphicInvoke)( internal::BindStateBase*, typename internal::CallbackParamTraits<A1>::ForwardType, typename internal::CallbackParamTraits<A2>::ForwardType, typename internal::CallbackParamTraits<A3>::ForwardType, typename internal::CallbackParamTraits<A4>::ForwardType, typename internal::CallbackParamTraits<A5>::ForwardType, typename internal::CallbackParamTraits<A6>::ForwardType, typename internal::CallbackParamTraits<A7>::ForwardType); }; // Syntactic sugar to make Callbacks<void(void)> easier to declare since it // will be used in a lot of APIs with delayed execution. typedef Callback<void(void)> Closure; } // namespace base #endif // BASE_CALLBACK_H