// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "platform/WaitableEvent.h"

#include "base/synchronization/waitable_event.h"
#include "platform/heap/SafePoint.h"
#include "platform/heap/ThreadState.h"
#include "wtf/Optional.h"
#include "wtf/PtrUtil.h"
#include <vector>

namespace blink {

WaitableEvent::WaitableEvent(ResetPolicy policy, InitialState state) {
  m_impl = WTF::wrapUnique(new base::WaitableEvent(
      policy == ResetPolicy::Manual
          ? base::WaitableEvent::ResetPolicy::MANUAL
          : base::WaitableEvent::ResetPolicy::AUTOMATIC,
      state == InitialState::Signaled
          ? base::WaitableEvent::InitialState::SIGNALED
          : base::WaitableEvent::InitialState::NOT_SIGNALED));
}

WaitableEvent::~WaitableEvent() {}

void WaitableEvent::reset() {
  m_impl->Reset();
}

void WaitableEvent::wait() {
  if (ThreadState::current()) {
    // We only enter a safe point scope if the thread is attached, ex. never
    // during shutdown.
    // TODO(esprehn): Why can't SafePointScope do this for us?
    SafePointScope scope(BlinkGC::HeapPointersOnStack);
    m_impl->Wait();
  } else {
    m_impl->Wait();
  }
}

void WaitableEvent::signal() {
  m_impl->Signal();
}

size_t WaitableEvent::waitMultiple(const WTF::Vector<WaitableEvent*>& events) {
  std::vector<base::WaitableEvent*> baseEvents;
  for (size_t i = 0; i < events.size(); ++i)
    baseEvents.push_back(events[i]->m_impl.get());
  size_t idx =
      base::WaitableEvent::WaitMany(baseEvents.data(), baseEvents.size());
  DCHECK_LT(idx, events.size());
  return idx;
}

}  // namespace blink