Added onDisconnected callback called after calling db:disconnect.

.gitignore

@@ -11,4 +11,5 @@
 *.zip
 cmake-build-debug
 .idea
-.vs
+.vs
+.cache

README.md

@@ -58,6 +58,7 @@ Database:connect()
 Database:disconnect(shouldWait)
 -- Returns nothing
 -- disconnects from the database and waits for all queries to finish if shouldWait is true
+-- This function calls the onDisconnected callback if it existed on the database before the database was connected.
 
 Database:query( sql )
 -- Returns [Query]
@@ -149,6 +150,11 @@ Database.onConnected( db )
 Database.onConnectionFailed( db, err )
 -- Called when the connection to the MySQL server fails, [String] err is why.
 
+Database.onDisconnected( db )
+-- Called after Database.disconnect has been called and all queries have finished executing
+-- Note: You have to set this callback before calling Database:connect() or it will not be called.
+
+
 -- Query/PreparedQuery object (transactions also inherit all functions, some have no effect though)
 
 -- Functions

src/lua/LuaDatabase.cpp

@@ -103,6 +103,12 @@ MYSQLOO_LUA_FUNCTION(connect) {
         LUA->Push(1);
         database->m_tableReference = LuaReferenceCreate(LUA);
     }
+
+    LUA->ReferencePush(database->m_tableReference);
+    LUA->GetField(-1, "onDisconnected");
+    database->m_hasOnDisconnected = LUA->IsType(-1, GarrysMod::Lua::Type::Function);
+    LUA->Pop(2); // callback, table
+
     database->m_database->connect();
     return 0;
 }
@@ -351,7 +357,6 @@ void LuaDatabase::think(ILuaBase *LUA) {
                 LUA->ReferencePush(this->m_tableReference);
                 pcallWithErrorReporter(LUA, 1);
             }
-            LUA->Pop(); //Callback function
         } else {
             LUA->GetField(-1, "onConnectionFailed");
             if (LUA->GetType(-1) == GarrysMod::Lua::Type::Function) {
@@ -360,11 +365,15 @@ void LuaDatabase::think(ILuaBase *LUA) {
                 LUA->PushString(error.c_str());
                 pcallWithErrorReporter(LUA, 2);
             }
-            LUA->Pop(); //Callback function
         }
+        LUA->Pop(); // DB Table
 
-        LuaReferenceFree(LUA, this->m_tableReference);
-        this->m_tableReference = 0;
+        if (!this->m_hasOnDisconnected) {
+            // Only free the table reference if we do not have an onDisconnected callback.
+            // Otherwise, it will be freed after the onDisconnected callback was called.
+            LuaReferenceFree(LUA, this->m_tableReference);
+            this->m_tableReference = 0;
+        }
     }
 
     //Run callbacks of finished queries
@@ -372,6 +381,21 @@ void LuaDatabase::think(ILuaBase *LUA) {
     for (auto &pair: finishedQueries) {
         LuaQuery::runCallback(LUA, pair.first, pair.second);
     }
+
+    if (database->wasDisconnected() && this->m_hasOnDisconnected && this->m_tableReference != 0) {
+        this->m_hasOnDisconnected = false;
+
+        LUA->ReferencePush(this->m_tableReference);
+
+        LUA->GetField(-1, "onDisconnected");
+        if (LUA->GetType(-1) == GarrysMod::Lua::Type::Function) {
+            LUA->ReferencePush(this->m_tableReference);
+            pcallWithErrorReporter(LUA, 1);
+        }
+        LUA->Pop(1); // DB Table
+
+        LuaReferenceFree(LUA, this->m_tableReference);
+    }
 }
 
 void LuaDatabase::onDestroyedByLua(ILuaBase *LUA) {

src/lua/LuaDatabase.h

@@ -17,6 +17,7 @@ public:
     void think(ILuaBase *LUA);
 
     int m_tableReference = 0;
+    bool m_hasOnDisconnected = false;
     std::shared_ptr<Database> m_database;
     bool m_dbCallbackRan = false;
 

src/lua/LuaObject.cpp

@@ -68,6 +68,11 @@ LUA_FUNCTION(errorReporter) {
     return 1;
 }
 
+/**
+ * Similar to LUA->PCall but also uses an error reporter and prints the
+ * error to the console using ErrorNoHalt (if it exists).
+ * Consumes the function and all nargs arguments on the stack, does not return any values.
+ */
 void LuaObject::pcallWithErrorReporter(ILuaBase *LUA, int nargs) {
     LUA->PushCFunction(errorReporter);
     int errorHandlerIndex = LUA->Top() - nargs - 1;

src/mysql/Database.cpp

@@ -215,7 +215,13 @@ void Database::disconnect(bool wait) {
     if (wait && m_thread.joinable()) {
         m_thread.join();
     }
-    disconnected = true;
+}
+
+/*
+ * Returns true after the database has been fully disconnected and no more queries are in the queue.
+ */
+bool Database::wasDisconnected() {
+    return disconnected;
 }
 
 /* Returns the status of the database, constants can be found in GMModule
@@ -361,6 +367,7 @@ void Database::connectRun() {
         if (m_status == DATABASE_CONNECTED) {
             m_status = DATABASE_NOT_CONNECTED;
         }
+        disconnected = true;
     });
     {
         auto connectionSignaler = finally([&] { m_connectWakeupVariable.notify_one(); });

src/mysql/Database.h

@@ -115,6 +115,7 @@ public:
         return finishedQueries.clear();
     }
 
+    bool wasDisconnected();
 private:
     Database(std::string host, std::string username, std::string pw, std::string database, unsigned int port,
              std::string unixSocket);
@@ -158,10 +159,10 @@ private:
     bool shouldAutoReconnect = true;
     bool useMultiStatements = true;
     bool startedConnecting = false;
-    bool disconnected = false;
     bool m_canWait = false;
     std::pair<std::shared_ptr<IQuery>, std::shared_ptr<IQueryData>> m_waitingQuery = {nullptr, nullptr};
     std::atomic<bool> m_success{true};
+    std::atomic<bool> disconnected { false };
     std::atomic<bool> m_connectionDone{false};
     std::atomic<bool> cachePreparedStatements{true};
     std::condition_variable m_queryWakeupVariable{};