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 (Function< void(AsyncResult &)> *afterStopped=nullptr)
	Ask to stop current async operation. More...
bool	isFree () const
	Returns true if this request is free. More...
bool	isCancelling () const
	Returns true if this request is being cancelled. More...
bool	isActive () const
	Returns true if this request is active or being reactivated. More...
Type	getType () const
	Returns request type. More...

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));
    }
    int numRequests = 0;
    eventLoop.enumerateRequests([&](AsyncRequest&) { numRequests++; });
    SC_TEST_EXPECT(eventLoop.run());
    SC_TEST_EXPECT(numRequests == NUM_WORKS);
 
    // 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