Implementation of a future used to wait for an operation to complete and access the value returned by that operation. More...

#include <Future.h>

Public Types
typedef Future< ResultT >	self_t

typedef std::function< ResultT(void)>	get_func_t
	Callback function returning the result value. More...

typedef std::function< bool(ResultT *)>	test_func_t
	Callback function to test for the availability of the result value. More...

typedef std::function< void(void)>	destroy_func_t
	Callback function called upon destruction. More...

Public Member Functions
	Future () noexcept(std::is_nothrow_constructible< ResultT >::value)=default
	Default constructor, creates a future that invalid. More...

	Future (ResultT result) noexcept(std::is_nothrow_move_constructible< ResultT >::value)
	Create a future from an already available value. More...

	Future (get_func_t get_func) noexcept
	Create a future using a function that returns the value. More...

	Future (get_func_t get_func, test_func_t test_func) noexcept
	Create a future using a function that returns the value and a function to test whether the value returned by `get_func` is ready. More...

	Future (get_func_t get_func, test_func_t test_func, destroy_func_t destroy_func) noexcept
	Create a future using a function that returns the value and a function to test whether the value returned by `get_func` is ready, plus a function to be called upon destruction of the future. More...

	Future (const self_t &other)=delete
	Copy construction is not permited. More...

	Future (self_t &&other) noexcept(std::is_nothrow_move_assignable< Future >::value)
	Move constructor. More...

	~Future ()
	Destructor. More...

self_t &	operator= (const self_t &other)=delete
	Copy assignment is not permited. More...

self_t &	operator= (self_t &&other) noexcept(std::is_nothrow_move_assignable< ResultT >::value)
	Move assignment. More...

void	wait ()
	Wait for the value to become available. More...

bool	test ()
	Test whether the value is available. More...

ResultT	get ()
	Return the value after making sure that the value is available. More...

bool	valid () noexcept
	Check whether the future is valid, i.e., whether either a value or a function to access the valid has been provided. More...

Friends
template<typename ResultT_ >
std::ostream &	operator<< (std::ostream &os, const Future< ResultT_ > &future)

Detailed Description

template<typename ResultT>
class dash::Future< ResultT >

Implementation of a future used to wait for an operation to complete and access the value returned by that operation.

Definition at line 20 of file Future.h.

Member Typedef Documentation

◆ destroy_func_t

template<typename ResultT>

typedef std::function<void (void)> dash::Future< ResultT >::destroy_func_t

Callback function called upon destruction.

Definition at line 38 of file Future.h.

◆ get_func_t

template<typename ResultT>

typedef std::function<ResultT (void)> dash::Future< ResultT >::get_func_t

Callback function returning the result value.

Definition at line 28 of file Future.h.

◆ test_func_t

template<typename ResultT>

typedef std::function<bool (ResultT*)> dash::Future< ResultT >::test_func_t

Callback function to test for the availability of the result value.

Definition at line 33 of file Future.h.

Constructor & Destructor Documentation

◆ Future() [1/7]

template<typename ResultT>

dash::Future< ResultT >::Future ( ) const

defaultnoexcept

Default constructor, creates a future that invalid.

See also: dash::Future::valid

Referenced by dash::Future< ResultT >::Future(), and dash::Future< void >::Future().

◆ Future() [2/7]

template<typename ResultT>

dash::Future< ResultT >::Future ( ResultT result )

inlinenoexcept

Create a future from an already available value.

Definition at line 71 of file Future.h.

   : _value(std::move(result)),
     _ready(true)
   { }

◆ Future() [3/7]

template<typename ResultT>

dash::Future< ResultT >::Future ( get_func_t get_func )

inlinenoexcept

Create a future using a function that returns the value.

Parameters

get_func Function returning the result value.

Definition at line 81 of file Future.h.

     : _get_func(std::move(get_func))
   {
   }

◆ Future() [4/7]

template<typename ResultT>

dash::Future< ResultT >::Future	(	get_func_t	get_func,
		test_func_t	test_func
	)

inlinenoexcept

Create a future using a function that returns the value and a function to test whether the value returned by get_func is ready.

Parameters

get_func	Function returning the result value.
test_func	Function returning `true` and assigning the result value to the pointer passed to it if the value is available.

Definition at line 94 of file Future.h.

     : _get_func(std::move(get_func))
     , _test_func(std::move(test_func))
   {
   }

◆ Future() [5/7]

template<typename ResultT>

dash::Future< ResultT >::Future	(	get_func_t	get_func,
		test_func_t	test_func,
		destroy_func_t	destroy_func
	)

inlinenoexcept

Create a future using a function that returns the value and a function to test whether the value returned by get_func is ready, plus a function to be called upon destruction of the future.

Parameters

get_func	Function returning the result value.
test_func	Function returning `true` and assigning the result value to the pointer passed to it if the value is available.
destroy_func	Function called upon destruction of the future.

Definition at line 110 of file Future.h.

References dash::Future< ResultT >::Future().

     : _get_func(std::move(get_func))
     , _test_func(std::move(test_func))
     , _destroy_func(std::move(destroy_func))
   {
   }

◆ Future() [6/7]

template<typename ResultT>

dash::Future< ResultT >::Future ( const self_t & other )

delete

Copy construction is not permited.

◆ Future() [7/7]

template<typename ResultT>

dash::Future< ResultT >::Future ( self_t && other )

inlinenoexcept

Move constructor.

Definition at line 126 of file Future.h.

   {
     *this = std::move(other);
   }

◆ ~Future()

template<typename ResultT>

dash::Future< ResultT >::~Future ( )

inline

Destructor.

Calls the destroy_func passed to the constructor, if available.

Definition at line 136 of file Future.h.

References dash::Future< ResultT >::operator=().

             {
     if (_destroy_func) {
       _destroy_func();
     }
   }

Member Function Documentation

◆ get()

template<typename ResultT>

ResultT dash::Future< ResultT >::get ( )

inline

Return the value after making sure that the value is available.

Definition at line 209 of file Future.h.

References dash::Future< ResultT >::wait().

   {
     DASH_LOG_TRACE_VAR("Future.get()", _ready);
     wait();
     DASH_LOG_TRACE_VAR("Future.get >", _value);
     return _value;
   }

◆ operator=() [1/2]

template<typename ResultT>

self_t& dash::Future< ResultT >::operator= ( const self_t & other )

delete

Copy assignment is not permited.

Referenced by dash::Future< ResultT >::~Future(), and dash::Future< void >::~Future().

◆ operator=() [2/2]

template<typename ResultT>

self_t& dash::Future< ResultT >::operator= ( self_t && other )

inlinenoexcept

Move assignment.

Definition at line 150 of file Future.h.

   {
     _get_func     = std::move(other._get_func);
     _test_func    = std::move(other._test_func);
     _destroy_func = std::move(other._destroy_func);
     _value        = std::move(other._value);
     _ready        = other._ready;
     return *this;
   }

◆ test()

template<typename ResultT>

bool dash::Future< ResultT >::test ( )

inline

Test whether the value is available.

It is safe to call get after this call returned true. This function will block if no test-function has been provided.

Returns: true if the value is available, false otherwise.

Definition at line 189 of file Future.h.

   {
     if (!_ready) {
       if (_test_func) {
         _ready = _test_func(&_value);
       } else if (_get_func) {
         _value = _get_func();
         _ready = true;
       } else {
         DASH_THROW(
           dash::exception::RuntimeError,
           "Future not initialized with function");
       }
     }
     return _ready;
   }

◆ valid()

template<typename ResultT>

bool dash::Future< ResultT >::valid ( )

inlinenoexcept

Check whether the future is valid, i.e., whether either a value or a function to access the valid has been provided.

Definition at line 222 of file Future.h.

   {
     return (_ready || _get_func != nullptr);
   }

◆ wait()

template<typename ResultT>

void dash::Future< ResultT >::wait ( )

inline

Wait for the value to become available.

It is safe to call get after this call returned.

Definition at line 165 of file Future.h.

Referenced by dash::Future< ResultT >::get(), dash::Future< void >::get(), and dash::summa().

   {
     DASH_LOG_TRACE_VAR("Future.wait()", _ready);
     if (_ready) {
       return;
     }
     if (!_get_func) {
       DASH_LOG_ERROR("Future.wait()", "No function");
       DASH_THROW(
         dash::exception::RuntimeError,
         "Future not initialized with function");
     }
     _value = _get_func();
     _ready = true;
     DASH_LOG_TRACE_VAR("Future.wait >", _ready);
   }

The documentation for this class was generated from the following file:

/tmp/tmporruphar/dash/include/dash/Future.h

Public Types

Public Member Functions

Friends

Detailed Description

template<typename ResultT> class dash::Future< ResultT >

Member Typedef Documentation

◆ destroy_func_t

◆ get_func_t

◆ test_func_t

Constructor & Destructor Documentation

◆ Future() [1/7]

◆ Future() [2/7]

◆ Future() [3/7]

◆ Future() [4/7]

◆ Future() [5/7]

◆ Future() [6/7]

◆ Future() [7/7]

◆ ~Future()

Member Function Documentation

◆ get()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ test()

◆ valid()

◆ wait()

template<typename ResultT>
class dash::Future< ResultT >