channel.cc

// Copyright 2016 Regents of the University of Michigan
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "channel.h"

using namespace std;

namespace dadrian {

WaitGroup::WaitGroup() : m_counter(0) {}

void WaitGroup::add(size_t delta) {
    m_counter += delta;
}

void WaitGroup::done() {
    auto previous = m_counter.fetch_sub(1);
    if (previous == 1) {
        // Current is now zero, wake everything up
        m_cv.notify_all();
    }
}

void WaitGroup::wait() {
    unique_lock<mutex> lock(m_mutex);
    m_cv.wait(lock, [&]() { return m_counter == 0; });
}

} // namespace dadrian