shared_guard guard(m_instances_mtx);

auto i = m_entries.find(key);

if (i != m_entries.end()) {

return i->second;

}

CPPA_LOG_DEBUG("no cache entry found for " << CPPA_ARG(key));

return {nullptr, exit_reason::not_exited};

bool add_attachable = false;

if (value != nullptr) {

shared_guard guard(m_instances_mtx);

auto i = m_entries.find(key);

if (i == m_entries.end()) {

auto entry = std::make_pair(key,

value_type(value,

exit_reason::not_exited));

upgrade_guard uguard(guard);

add_attachable = m_entries.insert(entry).second;

}

}

if (add_attachable) {

CPPA_LOG_INFO("added " << key);

struct eraser : attachable {

actor_id m_id;

actor_registry* m_registry;

eraser(actor_id id, actor_registry* s) : m_id(id), m_registry(s) { }

void actor_exited(std::uint32_t reason) {

m_registry->erase(m_id, reason);

}

bool matches(const token&) {

return false;

}

};

value->attach(new eraser(key, this));

}

exclusive_guard guard(m_instances_mtx);

auto i = m_entries.find(key);

if (i != m_entries.end()) {

auto& entry = i->second;

CPPA_LOG_INFO("erased " << key << ", reason = " << std::hex << reason);

entry.first = nullptr;

entry.second = reason;

}

size_t new_val = --m_running;

/*

else*/ if (new_val <= 1) {

std::unique_lock<std::mutex> guard(m_running_mtx);

m_running_cv.notify_all();

}

CPPA_LOG_TRACE(CPPA_ARG(expected));

std::unique_lock<std::mutex> guard(m_running_mtx);

while (m_running.load() != expected) {

m_running_cv.wait(guard);

}