subscriber.cpp
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/*
* Redox - A modern, asynchronous, and wicked fast C++11 client for Redis
*
* https://github.com/hmartiro/redox
*
* Copyright 2015 - Hayk Martirosyan <hayk.mart at gmail dot com>
*
* 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 <string.h>
#include "subscriber.hpp"
using namespace std;
namespace redox {
Subscriber::Subscriber(ostream &log_stream, log::Level log_level)
: rdx_(log_stream, log_level), logger_(rdx_.logger_) {}
Subscriber::~Subscriber() {}
void Subscriber::disconnect() {
stop();
wait();
}
void Subscriber::wait() { rdx_.wait(); }
// This is a fairly awkward way of shutting down, where
// we pause to wait for subscriptions to happen, and then
// unsubscribe from everything and wait for that to finish.
// The reason is because hiredis goes into
// a segfault in freeReplyObject() under redisAsyncDisconnect()
// if we don't do this first.
// TODO(hayk): look at hiredis, ask them what causes the error
void Subscriber::stop() {
this_thread::sleep_for(chrono::milliseconds(1000));
for (const string &topic : subscribedTopics())
unsubscribe(topic);
for (const string &topic : psubscribedTopics())
punsubscribe(topic);
{
unique_lock<mutex> ul(subscribed_topics_guard_);
cv_unsub_.wait(ul, [this] {
return (subscribed_topics_.size() == 0);
});
}
{
unique_lock<mutex> ul(psubscribed_topics_guard_);
cv_punsub_.wait(ul, [this] {
return (psubscribed_topics_.size() == 0);
});
}
for (Command<redisReply *> *c : commands_)
c->free();
rdx_.stop();
}
// For debugging only
void debugReply(Command<redisReply *> c) {
redisReply *reply = c.reply();
cout << "------" << endl;
cout << c.cmd() << " " << (reply->type == REDIS_REPLY_ARRAY) << " " << (reply->elements) << endl;
for (size_t i = 0; i < reply->elements; i++) {
redisReply *r = reply->element[i];
cout << "element " << i << ", reply type = " << r->type << " ";
if (r->type == REDIS_REPLY_STRING)
cout << r->str << endl;
else if (r->type == REDIS_REPLY_INTEGER)
cout << r->integer << endl;
else
cout << "some other type" << endl;
}
cout << "------" << endl;
}
void Subscriber::subscribeBase(const string cmd_name, const string topic,
function<void(const string &, const string &)> msg_callback,
function<void(const string &)> sub_callback,
function<void(const string &)> unsub_callback,
function<void(const string &, int)> err_callback) {
Command<redisReply *> &sub_cmd = rdx_.commandLoop<redisReply *>(
{cmd_name, topic},
[this, topic, msg_callback, err_callback, sub_callback, unsub_callback](
Command<redisReply *> &c) {
if (!c.ok()) {
num_pending_subs_--;
if (err_callback)
err_callback(topic, c.status());
return;
}
redisReply *reply = c.reply();
// If the last entry is an integer, then it is a [p]sub/[p]unsub command
if ((reply->type == REDIS_REPLY_ARRAY) &&
(reply->element[reply->elements - 1]->type == REDIS_REPLY_INTEGER)) {
if (!strncmp(reply->element[0]->str, "sub", 3)) {
lock_guard<mutex> lg(subscribed_topics_guard_);
subscribed_topics_.insert(topic);
num_pending_subs_--;
if (sub_callback)
sub_callback(topic);
} else if (!strncmp(reply->element[0]->str, "psub", 4)) {
lock_guard<mutex> lg(psubscribed_topics_guard_);
psubscribed_topics_.insert(topic);
num_pending_subs_--;
if (sub_callback)
sub_callback(topic);
} else if (!strncmp(reply->element[0]->str, "uns", 3)) {
lock_guard<mutex> lg(subscribed_topics_guard_);
subscribed_topics_.erase(topic);
if (unsub_callback)
unsub_callback(topic);
cv_unsub_.notify_all();
} else if (!strncmp(reply->element[0]->str, "puns", 4)) {
lock_guard<mutex> lg(psubscribed_topics_guard_);
psubscribed_topics_.erase(topic);
if (unsub_callback)
unsub_callback(topic);
cv_punsub_.notify_all();
}
else
logger_.error() << "Unknown pubsub message: " << reply->element[0]->str;
}
// Message for subscribe
else if ((reply->type == REDIS_REPLY_ARRAY) && (reply->elements == 3)) {
char *msg = reply->element[2]->str;
int len = reply->element[2]->len;
if (msg && msg_callback)
msg_callback(topic, string(msg, len));
}
// Message for psubscribe
else if ((reply->type == REDIS_REPLY_ARRAY) && (reply->elements == 4)) {
char *msg = reply->element[3]->str;
int len = reply->element[3]->len;
if (msg && msg_callback)
msg_callback(reply->element[2]->str, string(msg, len));
}
else
logger_.error() << "Unknown pubsub message of type " << reply->type;
},
1e10 // To keep the command around for a few hundred years
);
// Add it to the command list
commands_.insert(&sub_cmd);
num_pending_subs_++;
}
void Subscriber::subscribe(const string topic,
function<void(const string &, const string &)> msg_callback,
function<void(const string &)> sub_callback,
function<void(const string &)> unsub_callback,
function<void(const string &, int)> err_callback) {
lock_guard<mutex> lg(subscribed_topics_guard_);
if (subscribed_topics_.find(topic) != subscribed_topics_.end()) {
logger_.warning() << "Already subscribed to " << topic << "!";
return;
}
subscribeBase("SUBSCRIBE", topic, msg_callback, sub_callback, unsub_callback, err_callback);
}
void Subscriber::psubscribe(const string topic,
function<void(const string &, const string &)> msg_callback,
function<void(const string &)> sub_callback,
function<void(const string &)> unsub_callback,
function<void(const string &, int)> err_callback) {
lock_guard<mutex> lg(psubscribed_topics_guard_);
if (psubscribed_topics_.find(topic) != psubscribed_topics_.end()) {
logger_.warning() << "Already psubscribed to " << topic << "!";
return;
}
subscribeBase("PSUBSCRIBE", topic, msg_callback, sub_callback, unsub_callback, err_callback);
}
void Subscriber::unsubscribeBase(const string cmd_name, const string topic,
function<void(const string &, int)> err_callback) {
rdx_.command<redisReply *>({cmd_name, topic}, [topic, err_callback](Command<redisReply *> &c) {
if (!c.ok()) {
if (err_callback)
err_callback(topic, c.status());
return;
}
});
}
void Subscriber::unsubscribe(const string topic, function<void(const string &, int)> err_callback) {
lock_guard<mutex> lg(subscribed_topics_guard_);
if (subscribed_topics_.find(topic) == subscribed_topics_.end()) {
logger_.warning() << "Cannot unsubscribe from " << topic << ", not subscribed!";
return;
}
unsubscribeBase("UNSUBSCRIBE", topic, err_callback);
}
void Subscriber::punsubscribe(const string topic,
function<void(const string &, int)> err_callback) {
lock_guard<mutex> lg(psubscribed_topics_guard_);
if (psubscribed_topics_.find(topic) == psubscribed_topics_.end()) {
logger_.warning() << "Cannot punsubscribe from " << topic << ", not psubscribed!";
return;
}
unsubscribeBase("PUNSUBSCRIBE", topic, err_callback);
}
} // End namespace