inline MachineThreads& wasmThreads()
{
static LazyNeverDestroyed<MachineThreads> threads;
static std::once_flag once;
std::call_once(once, [] {
threads.construct();
});
return threads;
}
FunctionOverrides& FunctionOverrides::overrides()
{
static LazyNeverDestroyed<FunctionOverrides> overrides;
static std::once_flag initializeListFlag;
std::call_once(initializeListFlag, [] {
const char* overridesFileName = Options::functionOverrides();
overrides.construct(overridesFileName);
});
return overrides;
}
const Extensions3DCache& Extensions3DCache::singleton()
{
static std::once_flag onceFlag;
static LazyNeverDestroyed<Extensions3DCache> extensions3DCache;
std::call_once(onceFlag, []{
extensions3DCache.construct();
});
return extensions3DCache;
}
FunctionWhitelist& FunctionWhitelist::ensureGlobalWhitelist()
{
static LazyNeverDestroyed<FunctionWhitelist> functionWhitelist;
static std::once_flag initializeWhitelistFlag;
std::call_once(initializeWhitelistFlag, [] {
const char* functionWhitelistFile = Options::dfgWhitelist();
functionWhitelist.construct(functionWhitelistFile);
});
return functionWhitelist;
}
DefaultSharedWorkerRepository& DefaultSharedWorkerRepository::instance()
{
static std::once_flag onceFlag;
static LazyNeverDestroyed<DefaultSharedWorkerRepository> instance;
std::call_once(onceFlag, []{
instance.construct();
});
return instance;
}
NetworkStateNotifier& networkStateNotifier()
{
static std::once_flag onceFlag;
static LazyNeverDestroyed<NetworkStateNotifier> networkStateNotifier;
std::call_once(onceFlag, []{
networkStateNotifier.construct();
});
return networkStateNotifier;
}
// FIXME: move all guid-related functions to a DatabaseVersionTracker class.
static std::mutex& guidMutex()
{
static std::once_flag onceFlag;
static LazyNeverDestroyed<std::mutex> mutex;
std::call_once(onceFlag, []{
mutex.construct();
});
return mutex;
}
// Because of driver bugs, exiting the program when there are active pbuffers
// can crash the X server (this has been observed with the official Nvidia drivers).
// We need to ensure that we clean everything up on exit. There are several reasons
// that GraphicsContext3Ds will still be alive at exit, including user error (memory
// leaks) and the page cache. In any case, we don't want the X server to crash.
static HashSet<GLContextGLX*>& activeContexts()
{
static std::once_flag onceFlag;
static LazyNeverDestroyed<HashSet<GLContextGLX*>> contexts;
std::call_once(onceFlag, [] {
contexts.construct();
std::atexit([] {
for (auto* context : activeContexts())
context->clear();
});
});
return contexts;
}
void WorkQueue::concurrentApply(size_t iterations, WTF::Function<void (size_t index)>&& function)
{
if (!iterations)
return;
if (iterations == 1) {
function(0);
return;
}
class ThreadPool {
public:
ThreadPool()
{
// We don't need a thread for the current core.
unsigned threadCount = numberOfProcessorCores() - 1;
m_workers.reserveInitialCapacity(threadCount);
for (unsigned i = 0; i < threadCount; ++i) {
m_workers.append(Thread::create("ThreadPool Worker", [this] {
threadBody();
}));
}
}
size_t workerCount() const { return m_workers.size(); }
void dispatch(const WTF::Function<void ()>* function)
{
LockHolder holder(m_lock);
m_queue.append(function);
m_condition.notifyOne();
}
private:
NO_RETURN void threadBody()
{
while (true) {
const WTF::Function<void ()>* function;
{
LockHolder holder(m_lock);
m_condition.wait(m_lock, [this] {
return !m_queue.isEmpty();
});
function = m_queue.takeFirst();
}
(*function)();
}
}
Lock m_lock;
Condition m_condition;
Deque<const WTF::Function<void ()>*> m_queue;
Vector<Ref<Thread>> m_workers;
};
static LazyNeverDestroyed<ThreadPool> threadPool;
static std::once_flag onceFlag;
std::call_once(onceFlag, [] {
threadPool.construct();
});
// Cap the worker count to the number of iterations (excluding this thread)
const size_t workerCount = std::min(iterations - 1, threadPool->workerCount());
std::atomic<size_t> currentIndex(0);
std::atomic<size_t> activeThreads(workerCount + 1);
Condition condition;
Lock lock;
WTF::Function<void ()> applier = [&, function = WTFMove(function)] {
size_t index;
// Call the function for as long as there are iterations left.
while ((index = currentIndex++) < iterations)
function(index);
// If there are no active threads left, signal the caller.
if (!--activeThreads) {
LockHolder holder(lock);
condition.notifyOne();
}
};
for (size_t i = 0; i < workerCount; ++i)
threadPool->dispatch(&applier);
applier();
LockHolder holder(lock);
condition.wait(lock, [&] { return !activeThreads; });
}