ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

BLE: Improve SafeBool.h documentation.

pull/5392/head
Vincent Coubard 2017-10-24 10:53:25 -05:00
parent 4209e88b9e
commit 76722fe30a
1 changed files with 43 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
features/FEATURE_BLE/ble/SafeBool.h
View File

@ -19,10 +19,23 @@
/* Safe bool idiom, see : http://www.artima.com/cppsource/safebool.html */ /* Safe bool idiom, see : http://www.artima.com/cppsource/safebool.html */
/**
* @file
* @addtogroup ble
* @{
* @addtogroup common
* @{
*/
/**
* Private namespace used to host details of the SafeBool implementation.
*/
namespace SafeBool_ { namespace SafeBool_ {
/** /**
* @brief Base class for all intances of SafeBool. * Base class of all SafeBool instances.
* This base class reduces instantiation of trueTag function. *
* This non template base class exists to reduces the number of instantiation of
* the trueTag function.
*/ */
class base { class base {
template<typename> template<typename>
@ -40,7 +53,7 @@ protected:
void invalidTag() const; void invalidTag() const;
/** /**
* Member function which indicate true value. * Special member function which indicate a true value.
*/ */
void trueTag() const {} void trueTag() const {}
}; };
@ -49,9 +62,14 @@ protected:
} }
/** /**
* @brief template class SafeBool use CRTP to made boolean conversion easy and correct. * Safe conversion of objects in boolean context.
* Derived class should implement the function bool toBool() const to make this work. Inheritance *
* should be public. * Classes wanting to evaluation of their instances in boolean context must
* derive publicly from this class rather than implementing the easy to misuse
* operator bool().
*
* Descendant classes must implement the function bool toBool() const to enable
* the safe conversion in boolean context.
* *
* @tparam T Type of the derived class * @tparam T Type of the derived class
* *
@ -61,7 +79,7 @@ protected:
* public: * public:
* *
* // boolean conversion * // boolean conversion
* bool toBool() { * bool toBool() const {
* *
* } * }
* }; * };
@ -87,17 +105,17 @@ protected:
* if(a == b) { * if(a == b) {
* *
* } * }
*
*
* @endcode * @endcode
*/ */
template <typename T> template <typename T>
class SafeBool : public SafeBool_::base { class SafeBool : public SafeBool_::base {
public: public:
/** /**
* Bool operator implementation, derived class has to provide bool toBool() const function. * Bool operator implementation, derived class must provide a bool
* toBool() const function.
*/ */
operator BoolType_t() const { operator BoolType_t() const
{
return (static_cast<const T*>(this))->toBool() return (static_cast<const T*>(this))->toBool()
? &SafeBool<T>::trueTag : 0; ? &SafeBool<T>::trueTag : 0;
} }
@ -105,20 +123,32 @@ public:
/** /**
* Avoid conversion to bool between different classes. * Avoid conversion to bool between different classes.
*
* @important Will generate a compile time error if instantiated.
*/ */
template <typename T, typename U> template <typename T, typename U>
void operator==(const SafeBool<T>& lhs,const SafeBool<U>& rhs) { void operator==(const SafeBool<T>& lhs,const SafeBool<U>& rhs)
{
lhs.invalidTag(); lhs.invalidTag();
// return false; // return false;
} }
/** /**
* Avoid conversion to bool between different classes. * Avoid conversion to bool between different classes.
*
* @important Will generate a compile time error if instantiated.
*/ */
template <typename T,typename U> template <typename T,typename U>
void operator!=(const SafeBool<T>& lhs,const SafeBool<U>& rhs) { void operator!=(const SafeBool<T>& lhs,const SafeBool<U>& rhs)
{
lhs.invalidTag(); lhs.invalidTag();
// return false; // return false;
} }
/**
* @}
* @}
*/
#endif /* BLE_API_SAFE_BOOL_H_ */ #endif /* BLE_API_SAFE_BOOL_H_ */