Switch database mutex to recursive because we copy it everywhere

... and I have no idea if any of the calls are re-entrant. yay.

common/dbcore.cpp

@@ -34,7 +34,7 @@
 
 DBcore::DBcore()
 	: mysql(mysql_init(nullptr))
-	, m_mutex(std::make_shared<std::mutex>())
+	, m_mutex(std::make_shared<Mutex>())
 {
 }
 
@@ -220,12 +220,12 @@ bool DBcore::Open(
 
 bool DBcore::Open(uint32 *errnum, char *errbuf)
 {
+	// Expects m_mutex to already be locked.
+
 	if (errbuf) {
 		errbuf[0] = 0;
 	}
 
-	std::scoped_lock lock(*m_mutex);
-
 	if (GetStatus() == Connected) {
 		return true;
 	}
@@ -294,7 +294,7 @@ std::string DBcore::Escape(const std::string& s)
 	return temp.data();
 }
 
-void DBcore::SetMutex(const std::shared_ptr<std::mutex>& mutex)
+void DBcore::SetMutex(const std::shared_ptr<Mutex>& mutex)
 {
 	DBcore::m_mutex = mutex;
 }

common/dbcore.h

@@ -36,6 +36,8 @@ public:
 		Closed, Connected, Error
 	};
 
+	using Mutex = std::recursive_mutex;
+
 	DBcore();
 	~DBcore();
 	eStatus GetStatus() { return pStatus; }
@@ -59,7 +61,7 @@ public:
 		mysql      = o.mysql;
 		mysqlOwner = false;
 	}
-	void SetMutex(const std::shared_ptr<std::mutex>& mutex);
+	void SetMutex(const std::shared_ptr<Mutex>& mutex);
 
 	// only safe on connections shared with other threads if results buffered
 	// unsafe to use off main thread due to internal server logging
@@ -86,8 +88,7 @@ private:
 	bool    mysqlOwner = true;
 	eStatus pStatus = Closed;
 
-	std::shared_ptr<std::mutex> m_mutex;
-	std::mutex m_query_lock;
+	std::shared_ptr<Mutex> m_mutex;
 
 	std::string origin_host;
 

common/event/task_scheduler.cpp

@@ -95,7 +95,7 @@ void TaskScheduler::ProcessWork()
 			m_data->cv.wait(lock,
 				[this]
 			{
-				return !m_data->running || m_data->tasks.empty();
+				return !m_data->running || !m_data->tasks.empty();
 			});
 
 			if (!m_data->running)

common/mysql_stmt.cpp

@@ -35,7 +35,7 @@ void PreparedStmt::StmtDeleter::operator()(MYSQL_STMT* stmt) noexcept
 	mysql_stmt_close(stmt);
 }
 
-PreparedStmt::PreparedStmt(MYSQL& mysql, std::string query, std::mutex& mutex, StmtOptions opts)
+PreparedStmt::PreparedStmt(MYSQL& mysql, std::string query, DBcore::Mutex& mutex, StmtOptions opts)
 	: m_stmt(mysql_stmt_init(&mysql), { mutex })
 	, m_query(std::move(query))
 	, m_options(opts)

common/mysql_stmt.h

@@ -17,8 +17,8 @@
 */
 #pragma once
 
+#include "common/dbcore.h"
 
-#include "mysql.h"
 #include <cassert>
 #include <cstring>
 #include <memory>
@@ -185,7 +185,7 @@ public:
 		int64_t, uint64_t, float, double, bool, std::string_view, std::nullptr_t>;
 
 	PreparedStmt() = delete;
-	PreparedStmt(MYSQL& mysql, std::string query, std::mutex& mutex, StmtOptions opts = {});
+	PreparedStmt(MYSQL& mysql, std::string query, DBcore::Mutex& mutex, StmtOptions opts = {});
 
 	const std::string& GetQuery() const { return m_query; }
 	StmtOptions GetOptions() const { return m_options; }
@@ -221,7 +221,7 @@ private:
 
 	struct StmtDeleter
 	{
-		std::mutex& mutex;
+		DBcore::Mutex& mutex;
 
 		void operator()(MYSQL_STMT* stmt) noexcept;
 	};
@@ -235,7 +235,7 @@ private:
 	std::string m_query;
 	StmtOptions m_options = {};
 	bool m_need_bind = true;
-	std::mutex& m_mutex; // connection mutex
+	DBcore::Mutex& m_mutex; // connection mutex
 };
 
 } // namespace mysql

world/cli/cli_database_concurrency.cpp

@@ -76,7 +76,7 @@ void WorldserverCLI::TestDatabaseConcurrency(int argc, char **argv, argh::parser
 		return;
 	}
 
-	std::shared_ptr<std::mutex> sharedMutex = std::make_shared<std::mutex>();
+	std::shared_ptr<DBcore::Mutex> sharedMutex = std::make_shared<DBcore::Mutex>();
 
 	db.SetMutex(sharedMutex);
 

world/world_boot.cpp

@@ -180,7 +180,7 @@ bool WorldBoot::LoadDatabaseConnections()
 		// when database and content_db share the same underlying mysql connection
 		// it needs to be protected by a shared mutex otherwise we produce concurrency issues
 		// when database actions are occurring in different threads
-		std::shared_ptr<std::mutex> sharedMutex = std::make_shared<std::mutex>();
+		std::shared_ptr<DBcore::Mutex> sharedMutex = std::make_shared<DBcore::Mutex>();
 		database.SetMutex(sharedMutex);
 		content_db.SetMutex(sharedMutex);
 	}

zone/main.cpp

@@ -246,7 +246,7 @@ int main(int argc, char **argv)
 		// when database and content_db share the same underlying mysql connection
 		// it needs to be protected by a shared mutex otherwise we produce concurrency issues
 		// when database actions are occurring in different threads
-		std::shared_ptr<std::mutex> sharedMutex = std::make_shared<std::mutex>();
+		std::shared_ptr<DBcore::Mutex> sharedMutex = std::make_shared<DBcore::Mutex>();
 		database.SetMutex(sharedMutex);
 		content_db.SetMutex(sharedMutex);
 	}