SC::AsyncLoopWork Struct Reference

Executes work in a thread pool and then invokes a callback on the event loop thread. More...

#include <Async.h>

Inheritance diagram for SC::AsyncLoopWork:

Public Types
using	CompletionData = AsyncCompletionData
	Completion data for AsyncLoopWakeUp. More...
using	Result = AsyncResultOf< AsyncLoopWork, CompletionData >
	Callback result for AsyncLoopWakeUp. More...
Public Types inherited from SC::AsyncRequest
enum class	Type : uint8_t {   LoopTimeout ,   LoopWakeUp ,   LoopWork ,   ProcessExit ,   SocketAccept ,   SocketConnect ,   SocketSend ,   SocketReceive ,   SocketClose ,   FileRead ,   FileWrite ,   FileClose ,   FilePoll }
	Type of async request. More...

Public Member Functions
SC::Result	setThreadPool (ThreadPool &threadPool)
	Sets the ThreadPool that will supply the thread to run the async work on. More...
SC::Result	start (AsyncEventLoop &eventLoop)
	Schedule work to be executed on a background thread, notifying the event loop when it's finished. More...
Public Member Functions inherited from SC::AsyncRequest
void	setDebugName (const char *newDebugName)
AsyncEventLoop *	getEventLoop () const
	Get the event loop associated with this AsyncRequest. More...
void	cacheInternalEventLoop (AsyncEventLoop &loop)
	Caches the event loop associated with this AsyncRequest. More...
Result	setThreadPoolAndTask (ThreadPool &pool, AsyncTask &task)
	Sets the thread pool and task to use for this request. More...
void	resetThreadPoolAndTask ()
	Resets anything previously set with setThreadPoolAndTask. More...
	AsyncRequest (Type type)
	Constructs a free async request of given type. More...
Result	stop ()
	Stops the async operation. More...
bool	isFree () const

Public Attributes
Function< SC::Result()>	work
Function< void(Result &)>	callback
	Called to execute the work in a background threadpool thread. More...
Public Attributes inherited from SC::AsyncRequest
AsyncRequest *	next = nullptr
AsyncRequest *	prev = nullptr

Additional Inherited Members
Protected Member Functions inherited from SC::AsyncRequest
Result	validateAsync ()
void	queueSubmission (AsyncEventLoop &eventLoop)
Protected Attributes inherited from SC::AsyncRequest
AsyncEventLoop *	eventLoop = nullptr
AsyncTask *	asyncTask = nullptr

Detailed Description

Executes work in a thread pool and then invokes a callback on the event loop thread.

AsyncLoopWork::work is invoked on one of the thread supplied by the ThreadPool passed during AsyncLoopWork::start. AsyncLoopWork::callback will be called as a completion, on the event loop thread AFTER work callback is finished.

    // This test creates a thread pool with 4 thread and 16 AsyncLoopWork.
    // All the 16 AsyncLoopWork are scheduled to do some work on a background thread.
    // After work is done, their respective after-work callback is invoked on the event loop thread.
 
    static constexpr int NUM_THREADS = 4;
    static constexpr int NUM_WORKS   = NUM_THREADS * NUM_THREADS;
 
    ThreadPool threadPool;
    SC_TEST_EXPECT(threadPool.create(NUM_THREADS));
 
    AsyncEventLoop eventLoop;
    SC_TEST_EXPECT(eventLoop.create());
 
    AsyncLoopWork works[NUM_WORKS];
 
    int         numAfterWorkCallbackCalls = 0;
    Atomic<int> numWorkCallbackCalls      = 0;
 
    for (int idx = 0; idx < NUM_WORKS; ++idx)
    {
        works[idx].work = [&]
        {
            // This work callback is called on some random threadPool thread
            Thread::Sleep(50);                 // Execute some work on the thread
            numWorkCallbackCalls.fetch_add(1); // Atomically increment this counter
            return Result(true);
        };
        works[idx].callback = [&](AsyncLoopWork::Result&)
        {
            // This after-work callback is invoked on the event loop thread.
            // More precisely this runs on the thread calling eventLoop.run().
            numAfterWorkCallbackCalls++; // No need for atomics here, callback is run inside loop thread
        };
        // Must always call setThreadPool at least once before start
        SC_TEST_EXPECT(works[idx].setThreadPool(threadPool));
        SC_TEST_EXPECT(works[idx].start(eventLoop));
    }
    SC_TEST_EXPECT(eventLoop.run());
 
    // Check that callbacks have been actually called
    SC_TEST_EXPECT(numWorkCallbackCalls.load() == NUM_WORKS);
    SC_TEST_EXPECT(numAfterWorkCallbackCalls == NUM_WORKS);

Member Typedef Documentation

CompletionData

using SC::AsyncLoopWork::CompletionData = AsyncCompletionData

Completion data for AsyncLoopWakeUp.

Result

using SC::AsyncLoopWork::Result = AsyncResultOf<AsyncLoopWork, CompletionData>

Callback result for AsyncLoopWakeUp.

Member Function Documentation

setThreadPool()

SC::Result SC::AsyncLoopWork::setThreadPool

(

ThreadPool &

threadPool

)

Sets the ThreadPool that will supply the thread to run the async work on.

Note

Always call this method at least once before AsyncLoopWork::start

start()

SC::Result SC::AsyncLoopWork::start

(

AsyncEventLoop &

eventLoop

)

Schedule work to be executed on a background thread, notifying the event loop when it's finished.

Parameters

eventLoop

The AsyncEventLoop where to schedule this work on

Note

Remember to call AsyncLoopWork::setThreadPool at least once before calling AsyncLoopWork::start

Member Data Documentation

callback

Function<void(Result&)> SC::AsyncLoopWork::callback

Called to execute the work in a background threadpool thread.

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

• Async.h