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#include <Access/AccessChangesNotifier.h>
#include <boost/range/algorithm/copy.hpp>
namespace DB
{
AccessChangesNotifier::AccessChangesNotifier() : handlers(std::make_shared<Handlers>())
{
}
AccessChangesNotifier::~AccessChangesNotifier() = default;
void AccessChangesNotifier::onEntityAdded(const UUID & id, const AccessEntityPtr & new_entity)
{
std::lock_guard lock{queue_mutex};
Event event;
event.id = id;
event.entity = new_entity;
event.type = new_entity->getType();
queue.push(std::move(event));
}
void AccessChangesNotifier::onEntityUpdated(const UUID & id, const AccessEntityPtr & changed_entity)
{
std::lock_guard lock{queue_mutex};
Event event;
event.id = id;
event.entity = changed_entity;
event.type = changed_entity->getType();
queue.push(std::move(event));
}
void AccessChangesNotifier::onEntityRemoved(const UUID & id, AccessEntityType type)
{
std::lock_guard lock{queue_mutex};
Event event;
event.id = id;
event.type = type;
queue.push(std::move(event));
}
scope_guard AccessChangesNotifier::subscribeForChanges(AccessEntityType type, const OnChangedHandler & handler)
{
std::lock_guard lock{handlers->mutex};
auto & list = handlers->by_type[static_cast<size_t>(type)];
list.push_back(handler);
auto handler_it = std::prev(list.end());
return [my_handlers = handlers, type, handler_it]
{
std::lock_guard lock2{my_handlers->mutex};
auto & list2 = my_handlers->by_type[static_cast<size_t>(type)];
list2.erase(handler_it);
};
}
scope_guard AccessChangesNotifier::subscribeForChanges(const UUID & id, const OnChangedHandler & handler)
{
std::lock_guard lock{handlers->mutex};
auto it = handlers->by_id.emplace(id, std::list<OnChangedHandler>{}).first;
auto & list = it->second;
list.push_back(handler);
auto handler_it = std::prev(list.end());
return [my_handlers = handlers, it, handler_it]
{
std::lock_guard lock2{my_handlers->mutex};
auto & list2 = it->second;
list2.erase(handler_it);
if (list2.empty())
my_handlers->by_id.erase(it);
};
}
scope_guard AccessChangesNotifier::subscribeForChanges(const std::vector<UUID> & ids, const OnChangedHandler & handler)
{
scope_guard subscriptions;
for (const auto & id : ids)
subscriptions.join(subscribeForChanges(id, handler));
return subscriptions;
}
void AccessChangesNotifier::sendNotifications()
{
/// Only one thread can send notification at any time.
std::lock_guard sending_notifications_lock{sending_notifications};
std::unique_lock queue_lock{queue_mutex};
while (!queue.empty())
{
auto event = std::move(queue.front());
queue.pop();
queue_lock.unlock();
std::vector<OnChangedHandler> current_handlers;
{
std::lock_guard handlers_lock{handlers->mutex};
boost::range::copy(handlers->by_type[static_cast<size_t>(event.type)], std::back_inserter(current_handlers));
auto it = handlers->by_id.find(event.id);
if (it != handlers->by_id.end())
boost::range::copy(it->second, std::back_inserter(current_handlers));
}
for (const auto & handler : current_handlers)
{
try
{
handler(event.id, event.entity);
}
catch (...)
{
tryLogCurrentException(__PRETTY_FUNCTION__);
}
}
queue_lock.lock();
}
}
}
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