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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/core/utils/threading/Executor.h>
#include <aws/core/utils/threading/ThreadTask.h>
#include <thread>
#include <cassert>
static const char* POOLED_CLASS_TAG = "PooledThreadExecutor";
using namespace Aws::Utils::Threading;
bool DefaultExecutor::SubmitToThread(std::function<void()>&& fx)
{
// Generalized lambda capture is C++14, using std::bind as a workaround to force moving fx (instead of copying)
std::function<void()> main = std::bind(
[this](std::function<void()>& storedFx)
{
storedFx();
Detach(std::this_thread::get_id());
},
std::move(fx)
);
State expected;
do
{
expected = State::Free;
if(m_state.compare_exchange_strong(expected, State::Locked))
{
std::thread t(std::move(main));
const auto id = t.get_id(); // copy the id before we std::move the thread
m_threads.emplace(id, std::move(t));
m_state = State::Free;
return true;
}
}
while(expected != State::Shutdown);
return false;
}
void DefaultExecutor::Detach(std::thread::id id)
{
State expected;
do
{
expected = State::Free;
if(m_state.compare_exchange_strong(expected, State::Locked))
{
auto it = m_threads.find(id);
assert(it != m_threads.end());
it->second.detach();
m_threads.erase(it);
m_state = State::Free;
return;
}
}
while(expected != State::Shutdown);
}
DefaultExecutor::~DefaultExecutor()
{
auto expected = State::Free;
while(!m_state.compare_exchange_strong(expected, State::Shutdown))
{
//spin while currently detaching threads finish
assert(expected == State::Locked);
expected = State::Free;
}
auto it = m_threads.begin();
while(!m_threads.empty())
{
it->second.join();
it = m_threads.erase(it);
}
}
PooledThreadExecutor::PooledThreadExecutor(size_t poolSize, OverflowPolicy overflowPolicy) :
m_sync(0, poolSize), m_poolSize(poolSize), m_overflowPolicy(overflowPolicy)
{
for (size_t index = 0; index < m_poolSize; ++index)
{
m_threadTaskHandles.push_back(Aws::New<ThreadTask>(POOLED_CLASS_TAG, *this));
}
}
PooledThreadExecutor::~PooledThreadExecutor()
{
for(auto threadTask : m_threadTaskHandles)
{
threadTask->StopProcessingWork();
}
m_sync.ReleaseAll();
for (auto threadTask : m_threadTaskHandles)
{
Aws::Delete(threadTask);
}
while(m_tasks.size() > 0)
{
std::function<void()>* fn = m_tasks.front();
m_tasks.pop();
if(fn)
{
Aws::Delete(fn);
}
}
}
bool PooledThreadExecutor::SubmitToThread(std::function<void()>&& fn)
{
//avoid the need to do copies inside the lock. Instead lets do a pointer push.
std::function<void()>* fnCpy = Aws::New<std::function<void()>>(POOLED_CLASS_TAG, std::forward<std::function<void()>>(fn));
{
std::lock_guard<std::mutex> locker(m_queueLock);
if (m_overflowPolicy == OverflowPolicy::REJECT_IMMEDIATELY && m_tasks.size() >= m_poolSize)
{
Aws::Delete(fnCpy);
return false;
}
m_tasks.push(fnCpy);
}
m_sync.Release();
return true;
}
std::function<void()>* PooledThreadExecutor::PopTask()
{
std::lock_guard<std::mutex> locker(m_queueLock);
if (m_tasks.size() > 0)
{
std::function<void()>* fn = m_tasks.front();
if (fn)
{
m_tasks.pop();
return fn;
}
}
return nullptr;
}
bool PooledThreadExecutor::HasTasks()
{
std::lock_guard<std::mutex> locker(m_queueLock);
return m_tasks.size() > 0;
}
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