[Database] Address deadlock in player events (#2974)

* DB mutex testing

* Mutex tweaks, native string escaping

common/dbcore.cpp

@@ -70,17 +70,20 @@ DBcore::~DBcore()
 // Sends the MySQL server a keepalive
 void DBcore::ping()
 {
-	if (!MDatabase.trylock()) {
+	if (!m_query_lock.try_lock()) {
 		// well, if's it's locked, someone's using it. If someone's using it, it doesnt need a keepalive
 		return;
 	}
 	mysql_ping(&mysql);
-	MDatabase.unlock();
+	m_query_lock.unlock();
 }
 
 MySQLRequestResult DBcore::QueryDatabase(std::string query, bool retryOnFailureOnce)
 {
-	return QueryDatabase(query.c_str(), query.length(), retryOnFailureOnce);
+	m_query_lock.lock();
+	auto r = QueryDatabase(query.c_str(), query.length(), retryOnFailureOnce);
+	m_query_lock.unlock();
+	return r;
 }
 
 bool DBcore::DoesTableExist(std::string table_name)
@@ -95,15 +98,11 @@ MySQLRequestResult DBcore::QueryDatabase(const char *query, uint32 querylen, boo
 	BenchTimer timer;
 	timer.reset();
 
-	LockMutex lock(&MDatabase);
-
 	// Reconnect if we are not connected before hand.
 	if (pStatus != Connected) {
 		Open();
 	}
 
-
-
 	// request query. != 0 indicates some kind of error.
 	if (mysql_real_query(&mysql, query, querylen) != 0) {
 		unsigned int errorNumber = mysql_errno(&mysql);
@@ -299,3 +298,12 @@ void DBcore::SetOriginHost(const std::string &origin_host)
 {
 	DBcore::origin_host = origin_host;
 }
+
+std::string DBcore::Escape(const std::string& s)
+{
+	const std::size_t s_len = s.length();
+	std::vector<char> temp((s_len * 2) + 1, '\0');
+	mysql_real_escape_string(&mysql, temp.data(), s.c_str(), s_len);
+
+	return temp.data();
+}

common/dbcore.h

@@ -12,6 +12,7 @@
 
 #include <mysql.h>
 #include <string.h>
+#include <mutex>
 
 class DBcore {
 public:
@@ -27,6 +28,7 @@ public:
 	void TransactionBegin();
 	void TransactionCommit();
 	void TransactionRollback();
+	std::string Escape(const std::string& s);
 	uint32 DoEscapeString(char *tobuf, const char *frombuf, uint32 fromlen);
 	void ping();
 	MYSQL *getMySQL() { return &mysql; }
@@ -57,6 +59,8 @@ private:
 	Mutex   MDatabase;
 	eStatus pStatus;
 
+	std::mutex m_query_lock{};
+
 	std::string origin_host;
 
 	char   *pHost;

common/events/player_event_logs.cpp

@@ -113,7 +113,9 @@ bool PlayerEventLogs::IsEventEnabled(PlayerEvent::EventType event)
 // this processes any current player events on the queue
 void PlayerEventLogs::ProcessBatchQueue()
 {
+	m_batch_queue_lock.lock();
 	if (m_record_batch_queue.empty()) {
+		m_batch_queue_lock.unlock();
 		return;
 	}
 
@@ -128,7 +130,6 @@ void PlayerEventLogs::ProcessBatchQueue()
 	);
 
 	// empty
-	m_batch_queue_lock.lock();
 	m_record_batch_queue = {};
 	m_batch_queue_lock.unlock();
 }

common/repositories/base/base_player_event_logs_repository.h

@@ -240,8 +240,8 @@ public:
 		v.push_back(columns[7] + " = " + std::to_string(e.z));
 		v.push_back(columns[8] + " = " + std::to_string(e.heading));
 		v.push_back(columns[9] + " = " + std::to_string(e.event_type_id));
-		v.push_back(columns[10] + " = '" + Strings::Escape(e.event_type_name) + "'");
+		v.push_back(columns[10] + " = '" + db.Escape(e.event_type_name) + "'");
-		v.push_back(columns[11] + " = '" + Strings::Escape(e.event_data) + "'");
+		v.push_back(columns[11] + " = '" + db.Escape(e.event_data) + "'");
 		v.push_back(columns[12] + " = FROM_UNIXTIME(" + (e.created_at > 0 ? std::to_string(e.created_at) : "null") + ")");
 
 		auto results = db.QueryDatabase(
@@ -274,8 +274,8 @@ public:
 		v.push_back(std::to_string(e.z));
 		v.push_back(std::to_string(e.heading));
 		v.push_back(std::to_string(e.event_type_id));
-		v.push_back("'" + Strings::Escape(e.event_type_name) + "'");
+		v.push_back("'" + db.Escape(e.event_type_name) + "'");
-		v.push_back("'" + Strings::Escape(e.event_data) + "'");
+		v.push_back("'" + db.Escape(e.event_data) + "'");
 		v.push_back("FROM_UNIXTIME(" + (e.created_at > 0 ? std::to_string(e.created_at) : "null") + ")");
 
 		auto results = db.QueryDatabase(
@@ -316,8 +316,8 @@ public:
 			v.push_back(std::to_string(e.z));
 			v.push_back(std::to_string(e.heading));
 			v.push_back(std::to_string(e.event_type_id));
-			v.push_back("'" + Strings::Escape(e.event_type_name) + "'");
+			v.push_back("'" + db.Escape(e.event_type_name) + "'");
-			v.push_back("'" + Strings::Escape(e.event_data) + "'");
+			v.push_back("'" + db.Escape(e.event_data) + "'");
 			v.push_back("FROM_UNIXTIME(" + (e.created_at > 0 ? std::to_string(e.created_at) : "null") + ")");
 
 			insert_chunks.push_back("(" + Strings::Implode(",", v) + ")");