echomap::ResultChannel< ResultT > Class Template Reference

Maintains a type-safe multi-observer single-consumer message bus for WorkerResult objects. More...

#include <ResultChannel.hpp>

Public Member Functions
template<class SlotT>
sigc::connection	observe (SlotT &&slot)
	Provide a new slot as an observer on the channel.
template<class SlotT> requires (!std::is_const_v<ResultT>)
sigc::connection	nominate_consumer (SlotT &&slot)
	Nominate the consumer slot for the channel.

Private Types
using	ObserverSignalT = sigc::signal<void(const ResultT&)>
using	ConsumerSignalT = sigc::signal<void(ResultT&&)>

Private Member Functions
void	publish (ResultT &&result)
	Publish a consumable result onto the channel for all observers, followed by the single consumer.
void	publish (const ResultT &result)
	Publish a non-consumable result onto the channel for all observers.

Private Attributes
ObserverSignalT	observers
ConsumerSignalT	consumer

Friends
class	WorkerResultDespatcher

Detailed Description

template<class ResultT>
class echomap::ResultChannel< ResultT >

Maintains a type-safe multi-observer single-consumer message bus for WorkerResult objects.

Template Parameters

ResultT

The type of result to broadcast on the channel. In practice, this is the first parameter of the subscribed slots.

Definition at line 29 of file ResultChannel.hpp.

Member Typedef Documentation

ConsumerSignalT

template<class ResultT>

using echomap::ResultChannel< ResultT >::ConsumerSignalT = sigc::signal<void(ResultT&&)>

private

Definition at line 72 of file ResultChannel.hpp.

ObserverSignalT

template<class ResultT>

using echomap::ResultChannel< ResultT >::ObserverSignalT = sigc::signal<void(const ResultT&)>

private

Definition at line 71 of file ResultChannel.hpp.

Member Function Documentation

nominate_consumer()

template<class ResultT>

template<class SlotT>
requires (!std::is_const_v<ResultT>)

sigc::connection echomap::ResultChannel< ResultT >::nominate_consumer ( SlotT && slot )

inlinenodiscard

Nominate the consumer slot for the channel.

Template Parameters

SlotT

The slot type signature, accepting ResultT&&.

Parameters

slot	The slot to consume the result following broadcast to observers.

Exceptions

std::runtime_error

The channel already had a nominated consumer.

Warning

This function may only be called once for each channel; otherwise, an exception will be thrown.

Definition at line 58 of file ResultChannel.hpp.

    {
        if (!consumer.empty())
            throw std::logic_error("Result channel already has a nominated consumer.");
 
        return consumer.connect(std::forward<SlotT>(slot));
    }

observe()

template<class ResultT>

template<class SlotT>

sigc::connection echomap::ResultChannel< ResultT >::observe ( SlotT && slot )

inlinenodiscard

Provide a new slot as an observer on the channel.

Template Parameters

SlotT

The slot type signature, accepting const ResultT&.

Parameters

slot	The slot to add to the subscribers of the channel.

Returns

The connection between the slot and the signal.

Definition at line 40 of file ResultChannel.hpp.

    {
        return observers.connect(std::forward<SlotT>(slot));
    }

publish() [1/2]

template<class ResultT>

void echomap::ResultChannel< ResultT >::publish ( const ResultT & result )

inlineprivate

Publish a non-consumable result onto the channel for all observers.

Parameters

result

A constant l-value reference to the result to publish on the channel.

Definition at line 105 of file ResultChannel.hpp.

    {
        observers.emit(result);
    }

publish() [2/2]

template<class ResultT>

void echomap::ResultChannel< ResultT >::publish ( ResultT && result )

inlineprivate

Publish a consumable result onto the channel for all observers, followed by the single consumer.

Parameters

result

An r-value reference to the result to publish on the channel.

Definition at line 79 of file ResultChannel.hpp.

    {
        std::exception_ptr observer_exception;
 
        // Emit const ResultT& to all observers.
        try {
            publish(result);
        } catch (...) {
            observer_exception = std::current_exception();
        }
 
        // If there is a nominated consumer, send it out.
        if (!consumer.empty())
            consumer.emit(std::move(result));
 
        if (observer_exception)
            std::rethrow_exception(observer_exception);
    }

Friends And Related Symbol Documentation

WorkerResultDespatcher

template<class ResultT>

friend class WorkerResultDespatcher

friend

Definition at line 69 of file ResultChannel.hpp.

Member Data Documentation

consumer

template<class ResultT>

ConsumerSignalT echomap::ResultChannel< ResultT >::consumer

private

Definition at line 113 of file ResultChannel.hpp.

observers

template<class ResultT>

ObserverSignalT echomap::ResultChannel< ResultT >::observers

private

Definition at line 112 of file ResultChannel.hpp.

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

• src/async/ResultChannel.hpp