subscriptionstore.cpp
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#include "subscriptionstore.h"
#include "cassert"
#include "rwlockguard.h"
SubscriptionNode::SubscriptionNode(const std::string &subtopic) :
subtopic(subtopic)
{
}
SubscriptionStore::SubscriptionStore() :
root(new SubscriptionNode("root")),
clients_by_id_const(clients_by_id)
{
}
void SubscriptionStore::addSubscription(Client_p &client, const std::string &topic)
{
const std::list<std::string> subtopics = split(topic, '/');
RWLockGuard lock_guard(&subscriptionsRwlock);
lock_guard.wrlock();
SubscriptionNode *deepestNode = root.get();
for(const std::string &subtopic : subtopics)
{
SubscriptionNode &nodeRef = *deepestNode;
std::unique_ptr<SubscriptionNode> &node = nodeRef.children[subtopic];
if (!node)
{
node.reset(new SubscriptionNode(subtopic));
}
deepestNode = node.get();
}
if (deepestNode)
{
deepestNode->subscribers.push_front(client->getClientId());
}
clients_by_id[client->getClientId()] = client;
lock_guard.unlock();
giveClientRetainedMessages(client, topic);
}
void SubscriptionStore::removeClient(const Client_p &client)
{
RWLockGuard lock_guard(&subscriptionsRwlock);
lock_guard.wrlock();
clients_by_id.erase(client->getClientId());
}
// TODO: should I implement cache, this needs to be changed to returning a list of clients.
void SubscriptionStore::publishNonRecursively(const MqttPacket &packet, const std::forward_list<std::string> &subscribers) const
{
for (const std::string &client_id : subscribers)
{
auto client_it = clients_by_id_const.find(client_id);
if (client_it != clients_by_id_const.end())
{
client_it->second->writeMqttPacketAndBlameThisClient(packet);
}
}
}
void SubscriptionStore::publishRecursively(std::list<std::string>::const_iterator cur_subtopic_it, std::list<std::string>::const_iterator end,
std::unique_ptr<SubscriptionNode> &this_node, const MqttPacket &packet) const
{
if (cur_subtopic_it == end) // This is the end of the topic path, so look for subscribers here.
{
publishNonRecursively(packet, this_node->subscribers);
return;
}
std::string cur_subtop = *cur_subtopic_it;
auto sub_node = this_node->children.find(cur_subtop);
const auto next_subtopic = ++cur_subtopic_it;
const auto pound_sign_node = this_node->children.find("#");
if (pound_sign_node != this_node->children.end())
{
publishNonRecursively(packet, pound_sign_node->second->subscribers);
}
if (sub_node != this_node->children.end())
{
publishRecursively(next_subtopic, end, sub_node->second, packet);
}
const auto plus_sign_node = this_node->children.find("+");
if (plus_sign_node != this_node->children.end())
{
publishRecursively(next_subtopic, end, plus_sign_node->second, packet);
}
}
void SubscriptionStore::queuePacketAtSubscribers(const std::string &topic, const MqttPacket &packet, const Client_p &sender)
{
// TODO: keep a cache of topics vs clients
const std::list<std::string> subtopics = split(topic, '/');
RWLockGuard lock_guard(&subscriptionsRwlock);
lock_guard.rdlock();
publishRecursively(subtopics.begin(), subtopics.end(), root, packet);
}
void SubscriptionStore::giveClientRetainedMessages(Client_p &client, const std::string &subscribe_topic)
{
RWLockGuard locker(&retainedMessagesRwlock);
locker.rdlock();
for(const RetainedMessage &rm : retainedMessages)
{
Publish publish(rm.topic, rm.payload, rm.qos);
publish.retain = true;
const MqttPacket packet(publish);
if (topicsMatch(subscribe_topic, rm.topic))
client->writeMqttPacket(packet);
}
}
void SubscriptionStore::setRetainedMessage(const std::string &topic, const std::string &payload, char qos)
{
RWLockGuard locker(&retainedMessagesRwlock);
locker.wrlock();
RetainedMessage rm(topic, payload, qos);
auto retained_ptr = retainedMessages.find(rm);
bool retained_found = retained_ptr != retainedMessages.end();
if (!retained_found && payload.empty())
return;
if (retained_found && payload.empty())
{
retainedMessages.erase(rm);
return;
}
if (retained_found)
retainedMessages.erase(rm);
retainedMessages.insert(std::move(rm));
}