GenericTaskQueue.h [plain text]
#pragma once
#include "Timer.h"
#include <wtf/Deque.h>
#include <wtf/Function.h>
#include <wtf/MainThread.h>
#include <wtf/UniqueRef.h>
#include <wtf/WeakPtr.h>
namespace WTF {
class Lock;
};
namespace WebCore {
template <typename T>
class TaskDispatcher {
WTF_MAKE_FAST_ALLOCATED;
public:
explicit TaskDispatcher(T* context)
: m_context(context)
{
}
void postTask(Function<void()>&& function)
{
ASSERT(m_context);
m_context->enqueueTaskForDispatcher(WTFMove(function));
}
private:
T* m_context;
};
template<>
class TaskDispatcher<Timer> : public CanMakeWeakPtr<TaskDispatcher<Timer>> {
WTF_MAKE_FAST_ALLOCATED;
public:
TaskDispatcher();
void postTask(Function<void()>&&);
private:
static Timer& sharedTimer();
static WTF::Lock& sharedLock();
static void sharedTimerFired();
static Deque<WeakPtr<TaskDispatcher<Timer>>>& pendingDispatchers();
void dispatchOneTask();
Deque<Function<void()>> m_pendingTasks;
};
template <typename T>
class GenericTaskQueue : public CanMakeWeakPtr<GenericTaskQueue<T>> {
WTF_MAKE_FAST_ALLOCATED;
public:
GenericTaskQueue()
: m_dispatcher(makeUniqueRef<TaskDispatcher<T>>())
{
}
explicit GenericTaskQueue(T& t)
: m_dispatcher(makeUniqueRef<TaskDispatcher<T>>(&t))
{
}
explicit GenericTaskQueue(T* t)
: m_dispatcher(makeUniqueRef<TaskDispatcher<T>>(t))
, m_isClosed(!t)
{
}
~GenericTaskQueue()
{
if (!isMainThread())
m_dispatcher->postTask([dispatcher = WTFMove(m_dispatcher)] { });
}
typedef WTF::Function<void ()> TaskFunction;
void enqueueTask(TaskFunction&& task)
{
if (m_isClosed)
return;
++m_pendingTasks;
m_dispatcher->postTask([weakThis = makeWeakPtr(*this), task = WTFMove(task)] {
if (!weakThis)
return;
ASSERT(weakThis->m_pendingTasks);
--weakThis->m_pendingTasks;
task();
});
}
void close()
{
cancelAllTasks();
m_isClosed = true;
}
void cancelAllTasks()
{
CanMakeWeakPtr<GenericTaskQueue<T>>::weakPtrFactory().revokeAll();
m_pendingTasks = 0;
}
bool hasPendingTasks() const { return m_pendingTasks; }
bool isClosed() const { return m_isClosed; }
private:
UniqueRef<TaskDispatcher<T>> m_dispatcher;
unsigned m_pendingTasks { 0 };
bool m_isClosed { false };
};
}