GenericTaskQueue.h [plain text]
#ifndef GenericTaskQueue_h
#define GenericTaskQueue_h
#include "Timer.h"
#include <wtf/Deque.h>
#include <wtf/WeakPtr.h>
namespace WebCore {
template <typename T>
class TaskDispatcher {
public:
TaskDispatcher(T& context)
: m_context(context)
{
}
void postTask(std::function<void()> f)
{
m_context.postTask(f);
}
private:
T& m_context;
};
template<>
class TaskDispatcher<Timer> {
public:
TaskDispatcher()
: m_timer(*this, &TaskDispatcher<Timer>::timerFired)
{
}
void postTask(std::function<void()> function)
{
m_queue.append(function);
m_timer.startOneShot(0);
}
void timerFired()
{
Deque<std::function<void()>> queue;
queue.swap(m_queue);
for (std::function<void()>& function : queue)
function();
}
Timer m_timer;
Deque<std::function<void()>> m_queue;
};
template <typename T>
class GenericTaskQueue {
public:
GenericTaskQueue()
: m_weakPtrFactory(this)
, m_dispatcher()
{
}
GenericTaskQueue(T& t)
: m_weakPtrFactory(this)
, m_dispatcher(t)
{
}
typedef std::function<void()> TaskFunction;
void enqueueTask(TaskFunction task)
{
if (m_isClosed)
return;
++m_pendingTasks;
auto weakThis = m_weakPtrFactory.createWeakPtr();
m_dispatcher.postTask([weakThis, task] {
if (!weakThis)
return;
ASSERT(weakThis->m_pendingTasks);
--weakThis->m_pendingTasks;
task();
});
}
void close()
{
cancelAllTasks();
m_isClosed = true;
}
void cancelAllTasks()
{
m_weakPtrFactory.revokeAll();
m_pendingTasks = 0;
}
bool hasPendingTasks() const { return m_pendingTasks; }
private:
WeakPtrFactory<GenericTaskQueue> m_weakPtrFactory;
TaskDispatcher<T> m_dispatcher;
unsigned m_pendingTasks { 0 };
bool m_isClosed { false };
};
}
#endif