Callback.h
繼承層次
- CallBack實現類
| 基類 | 第一層子類 | 第二層子類 | 第三層子類 |
|---|---|---|---|
| SimpleRefCount | CallbackImplBase | CallbackImpl | FunctorCallbackImpl |
| MemPtrCallbackImpl | |||
| BoundFunctorCallbackImpl | |||
| TwoBoundFunctorCallbackImpl | |||
| ThreeBoundFunctorCallbackImpl |
- Callback封裝類
- CallbackBase 封裝
Ptr<CallbackImplBase> m_impl - Callback CallbackBase的子類。根據傳入的不同實參，構造不同類型的callback。

- CallbackBase 封裝
模板整體說明
- CallbackImpl:有不同的特化子模板
- 根據重載（）操作符時需要的形參類型個數將Ti～Tk特化為empty類,調用是根據傳入的模板形參個數匹配相應的模板
- R：回調返回值
- FunctorCallbackImpl：CallbackImpl沒有默認值,
- T:泛函的類型（配套的，包括泛函返回類型，泛函形參類型）
- MemPtrCallbackImpl:CallbackImpl
- OBJ_PTR：object的類型
- MEM_PTR：object成員泛函的類型（包括泛函返回類型，泛函形參類型）
BoundFunctorCallbackImpl: CallbackImpl
- T:泛函類型
- R:回調返回值
- Tx：綁定的類型
- 回調時，總有一個類型為Tx的值作為回調的形參
CallBack:T1~T9:默認值為empty類
MakeCallback<>模板函數:根據傳入不同的形參，實例化不同版本
- 形參：泛函指針
- 根據傳入的普通泛函涉及的類型個數（返回值類型，形參類型個數）匹配不同回調形參個數的模板
- 形參：類成員泛函指針，類對象指針
- 根據傳入的類成員泛函的涉及的類型（返回值類型，形參類型個數）匹配不同回調形參的模板
- 形參：泛函指針，綁定的值（1~3個）
- 形參：泛函指針
CallbackTraits
- 模板1
c++ template <typename T> struct CallbackTraits; - 將指針轉化為引用，用于MemPtrCallBackImpl
c++ template <typename T> struct CallbackTraits<T *> { static T & GetReference (T * const p){ return *p; } };
CallbackImplBase
class CallbackImplBase : public SimpleRefCount<CallbackImplBase>
{
public:virtual ~CallbackImplBase () {}// Equality testvirtual bool IsEqual (Ptr<const CallbackImplBase> other) const = 0;
};
CallbackImpl
通過重載函數操作符"()"實現
- 模板聲明,該模板限定了最多能傳入9個形參給callback
template <typename R, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8, typename T9>
class CallbackImpl;
- 無參數特化模板
template <typename R>
class CallbackImpl<R,empty,empty,empty,empty,empty,empty,empty,empty,empty> : public CallbackImplBase {
public:virtual ~CallbackImpl () {}virtual R operator() (void) = 0; //!< Abstract operator
};
- 將模板形參T2~T9特例話為空 這是將基類模板中模板形參T2到T9特化為empty類型的一個例子（部分特化）
template <typename R, typename T1>
class CallbackImpl<R,T1,empty,empty,empty,empty,empty,empty,empty,empty> : public CallbackImplBase {
public:virtual ~CallbackImpl () {}virtual R operator() (T1) = 0; //!< Abstract operator
};
- 其他類似
- CallbackImpl的定義
template <typename R, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8, typename T9>
class CallbackImpl : public CallbackImplBase {
public:virtual ~CallbackImpl () {}virtual R operator() (T1, T2, T3, T4, T5, T6, T7, T8, T9) = 0; //!< Abstract operator
};
FunctorCallbackImpl
callbacks，CallbackImpl with functors
R:回調返回類型；
T :m_functor類型，T是一個函數指針的類型（包括函數形參列表，以及函數返回類型。而處于兼容性考慮，T應該是這樣的類型 R(*)(T1,T2.......)
template <typename T, typename R, typename T1, typename T2, typename T3, typename T4,typename T5, typename T6, typename T7, typename T8, typename T9>
class FunctorCallbackImpl : public CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,T9> {
public:
FunctorCallbackImpl (T const &functor):m_functor(functor){}
virtual ~FunctorCallbackImpl () {}
//無輸入參數的回調,
R operator() (void) {return m_functor (); }
//帶一個形參的回調R operator() (T1 a1) {return m_functor (a1); }
// 其他形參個數的回調類似
.......
virtual bool IsEqual (Ptr<const CallbackImplBase> other) const{
FunctorCallbackImpl<T,R,T1,T2,T3,T4,T5,T6,T7,T8,T9>const *otherDerived =dynamic_cast<FunctorCallbackImpl<T,R,T1,T2,T3,T4,T5,T6,T7,T8,T9> const *> (PeekPointer (other));//把其他類型的CallbackImpl轉換成FunctorCallbackImpl類
if (otherDerived == 0){return false;}
else if (otherDerived->m_functor != m_functor){return false;}
return true;
}
private:T m_functor; //!< the functor
};
MemPtrCallbackImpl
CallbackImpl for pointer to member functions
模板形參MEM_PTR：類成員泛函的類型（涉及泛函返回類型，形參類型表等）
template <typename OBJ_PTR, typename MEM_PTR, typename R, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8, typename T9>
class MemPtrCallbackImpl : public CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,T9> {
public:
MemPtrCallbackImpl (OBJ_PTR const&objPtr, MEM_PTR memPtr): m_objPtr (objPtr), m_memPtr (memPtr) {}virtual ~MemPtrCallbackImpl () {}//無形參成員函數回調實現R operator() (void) {return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr)();//將m_objPtr轉換成引用并調用其成員函數(*m_memPtr) //其他參數個數的成員函數的回調實現類似}.......virtual bool IsEqual (Ptr<const CallbackImplBase> other) const {MemPtrCallbackImpl<OBJ_PTR,MEM_PTR,R,T1,T2,T3,T4,T5,T6,T7,T8,T9> const *otherDerived=dynamic_cast<MemPtrCallbackImpl<OBJ_PTR,MEM_PTR,R,T1,T2,T3,T4,T5,T6,T7,T8,T9> const *> (PeekPointer (other));
if (otherDerived == 0){ return false; }
else if (otherDerived->m_objPtr != m_objPtr||therDerived->m_memPtr != m_memPtr){return false;}
return true;
}
private:OBJ_PTR const m_objPtr; //!< the object pointerMEM_PTR m_memPtr; //!< the member function pointer
};
BoundFunctorCallbackImpl
CallbackImpl for functors with first argument bound at construction
template <typename T, typename R, typename TX, typename T1, typename T2, typename T3, typename T4,typename T5, typename T6, typename T7, typename T8>
class BoundFunctorCallbackImpl : public CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,empty> {
public:
template <typename FUNCTOR, typename ARG>BoundFunctorCallbackImpl (FUNCTOR functor, ARG a): m_functor (functor), m_a (a) {}virtual ~BoundFunctorCallbackImpl () {}
//沒有可變類型形參的函數調用
R operator() (void) { return m_functor (m_a); }
//有一個Arg的函數回調
R operator() (T1 a1) { return m_functor (m_a,a1); }
//其他Arg個數的模板類似
virtual bool IsEqual (Ptr<const CallbackImplBase> other) const{
//實現和上面類似，先轉換，然后比較
}
private:T m_functor; //!< The functortypename TypeTraits<TX>::ReferencedType m_a; //!< the bound argument
};
TwoBoundFunctorCallbackImpl
CallbackImpl for functors with first two arguments bound at construction
template <typename T, typename R, typename TX1, typename TX2, typename T1, typename T2, typename T3, typename T4,typename T5, typename T6, typename T7>
class TwoBoundFunctorCallbackImpl : public CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,empty,empty> {
....
private:T m_functor; //!< The functortypename TypeTraits<TX1>::ReferencedType m_a1; //!< first bound argumenttypename TypeTraits<TX2>::ReferencedType m_a2; //!< second bound argument
};
}
ThreeBoundFunctorCallbackImpl
和上述類似
CallbackBase
class CallbackBase {
public:CallbackBase () : m_impl () {}Ptr<CallbackImplBase> GetImpl (void) const { return m_impl; }
protected:
CallbackBase (Ptr<CallbackImplBase> impl) : m_impl (impl) {}Ptr<CallbackImplBase> m_impl; //!< the pimplstatic std::string Demangle (const std::string& mangled);//符號重組？這個干什么的呢？
};
CallBack類
- 模板的示例化具有POD語義：需要的內存是自動管理的，并且允許用戶傳遞一個CallBack實例
- 模板使用pimpl idiom,傳遞CallBack類的值并將實現傳遞給其pimpl指針
- CallbackImpl和 FunctorCallbackImpl的子類可用于任何functor-type，而 MemPtrCallbackImpl 可用于某一個類的成員函數指針
- 通過reference list implementation實現CallBack類的值語義 ####Callback的構造函數
- 空構造函數
Callback () {} - 根據 Ptr構建Callback
c++ Callback (Ptr<CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,T9> > const &impl): CallbackBase (impl){} - 內置類型為FunctorCallbackImpl 創建一個FunctorCallbackImpl的實例（第一參數特化為iFUNCTOR類型，其他分別是R，T1等）。創建Create模板函數的此FunctorCallbackImpl的實例，給函數傳入實參functor，創建對應的Ptr的關于FunctorCallbackImpl的實例，將此Ptr對象作為CallBackBase類的構造函數實參
template <typename FUNCTOR>Callback (FUNCTOR const &functor, bool, bool) : CallbackBase(Create<FunctorCallbackImpl<FUNCTOR,R,T1,T2,T3,T4,T5,T6,T7,T8,T9> > (functor)){}
- 內置類型為MemPtrCallbackImpl 實例化MemPtrCallbackImpl，創建一個此類型的ptr，傳給Create函數的實參為objPtr和memPtr
template <typename OBJ_PTR, typename MEM_PTR>Callback (OBJ_PTR const &objPtr, MEM_PTR memPtr)：CallbackBase (Create<MemPtrCallbackImpl<OBJ_PTR,MEM_PTR,R,T1,T2,T3,T4,T5,T6,T7,T8,T9> > (objPtr, memPtr)){}
Callback的綁定
- Bind
- 構造一個綁定第一個Arg的回調
- 實例化一個BoundFunctorCallbackImpl，實例化傳入的模板實參解釋
-
Callback<R,T1,T2,T3,T4,T5,T6,T7,T8,T9>：BoundFunctorCallbackImpl內置泛函類型 - R：回調的返回類型
- T1:綁定的類型
- T2～T9:其他可控的函調形參類型
-
- 創建上述BoundFunctorCallbackImpl實例類的一個對象
- 傳給類的構造函數的實參：(*this):BoundFunctorCallbackImpl的內部泛函
- a :綁定的值
- 創建Ptr>對象impl
- 傳給Ptr構造函數的實參：上面創建的BoundFunctorCallbackImpl實例類臨時對象和false
- 以impl為實參構建Callback對象
template <typename T>
Callback<R,T2,T3,T4,T5,T6,T7,T8,T9> Bind (T a) {Ptr<CallbackImpl<R,T2,T3,T4,T5,T6,T7,T8,T9,empty> > impl =Ptr<CallbackImpl<R,T2,T3,T4,T5,T6,T7,T8,T9,empty> > (new BoundFunctorCallbackImpl<Callback<R,T1,T2,T3,T4,T5,T6,T7,T8,T9>,R,T1,T2,T3,T4,T5,T6,T7,T8,T9> (*this, a), false);return Callback<R,T2,T3,T4,T5,T6,T7,T8,T9> (impl);}
- 綁定前兩個 實現與Bind類似
template <typename TX1, typename TX2>
Callback<R,T3,T4,T5,T6,T7,T8,T9> TwoBind (TX1 a1, TX2 a2){..}
c++ callback、綁定前三個
實現與上面類似
template <typename TX1, typename TX2, typename TX3>Callback<R,T4,T5,T6,T7,T8,T9> ThreeBind (TX1 a1, TX2 a2, TX3 a3){...}
Callback的其他成員函數函數
template<typename R,typename T1 = empty, typename T2 = empty,typename T3 = empty, typename T4 = empty,typename T5 = empty, typename T6 = empty,typename T7 = empty, typename T8 = empty,typename T9 = empty>
class Callback : public CallbackBase {
public:
bool IsNull (void) const {return (DoPeekImpl () == 0) ? true : false;}void Nullify (void) {m_impl = 0;}//無輸入參數的回調R operator() (void) const {return (*(DoPeekImpl ()))();}//輸入一個參數的回調R operator() (T1 a1) const {return (*(DoPeekImpl ()))(a1);}// 其他輸入參數個數的回調與上述類似bool IsEqual (const CallbackBase &other) const {return m_impl->IsEqual (other.GetImpl ());}//如果other能轉換成我這種類型，返回truebool CheckType (const CallbackBase & other) const {return DoCheckType (other.GetImpl ());}void Assign (const CallbackBase &other) {DoAssign (other.GetImpl ());}private:CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,T9> *DoPeekImpl (void) const {return static_cast<CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,T9> *> (PeekPointer (m_impl));}//如果other能轉換成我這種類型，返回truebool DoCheckType (Ptr<const CallbackImplBase> other) const {if (other != 0 && dynamic_cast<const CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,T9> *> (PeekPointer (other)) != 0){ return true; //不為空且能轉換 }else if (other == 0){ return true; //傳入的Ptr為空 }else{ return false; }}void DoAssign (Ptr<const CallbackImplBase> other) {if (!DoCheckType (other)){Ptr<CallbackImpl<R,T1,T2,T3,T4,T5,T6,T7,T8,T9> > expected;NS_FATAL_ERROR (....);}m_impl = const_cast<CallbackImplBase *> (PeekPointer (other));}
}
MakeCallback模板函數
針對不同形參個數的函數指針的 MakeCallback函數模板
template <typename R>
Callback<R> MakeCallback (R (*fnPtr)()) {return Callback<R> (fnPtr, true, true);
}
template <typename R, typename T1>
Callback<R,T1> MakeCallback (R (*fnPtr)(T1)) {return Callback<R,T1> (fnPtr, true, true);
}
//其他類型函數指針的MakeCallback類似
針對不同形參個數的類成員函數指針的 MakeCallback函數模板
template <typename T, typename OBJ, typename R>
Callback<R> MakeCallback (R (T::*memPtr)(void), OBJ objPtr) {return Callback<R> (objPtr, memPtr);
}//const版本類似
template <typename T, typename OBJ, typename R, typename T1>
Callback<R,T1> MakeCallback (R (T::*memPtr)(T1), OBJ objPtr) {return Callback<R,T1> (objPtr, memPtr);
}
//其他類似
!= 符號的重載
MakeNullCallback的定義
MakeBoundCallback的定義（包括綁定一個，兩個等）
CallBack類的和屬性系統相關的東西
class CallbackValue : public AttributeValue
{
public:
CallbackValue ();CallbackValue (const CallbackBase &base);virtual ~CallbackValue ();void Set (CallbackBase base);template <typename T>bool GetAccessor (T &value) const;virtual Ptr<AttributeValue> Copy (void) const;virtual std::string SerializeToString (Ptr<const AttributeChecker> checker) const;virtual bool DeserializeFromString (std::string value, Ptr<const AttributeChecker> checker);private:CallbackBase m_value; //!< the CallbackBase
};
ATTRIBUTE_ACCESSOR_DEFINE (Callback);
ATTRIBUTE_CHECKER_DEFINE (Callback);
//Assign和CheckType函數是callback的成員函數。因此T應該也是一張callback又是哪里定義的
template <typename T>
bool CallbackValue::GetAccessor (T &value) const
{if (value.CheckType (m_value)){value.Assign (m_value);return true;}return false;
}
Callback.cc
- CallbackValue類成員函數的一些定義
- 定義和Callback相關的checker
ATTRIBUTE_CHECKER_IMPLEMENT (Callback);
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