Core/DBLayer: Convert async queries to new query callbacks and remove old callback handling

6 files changed, 162 insertions, 268 deletions

diff --git a/src/server/database/Database/DatabaseWorkerPool.cpp b/src/server/database/Database/DatabaseWorkerPool.cpp
index 0a3865009b0..e680ed834a3 100644
--- a/src/server/database/Database/DatabaseWorkerPool.cpp
+++ b/src/server/database/Database/DatabaseWorkerPool.cpp
@@ -17,6 +17,7 @@
 
 #include "DatabaseWorkerPool.h"
 #include "DatabaseEnv.h"
+#include "QueryCallback.h"
 
 #define MIN_MYSQL_SERVER_VERSION 50100u
 #define MIN_MYSQL_CLIENT_VERSION 50100u
@@ -146,23 +147,23 @@ PreparedQueryResult DatabaseWorkerPool<T>::Query(PreparedStatement* stmt)
 }
 
 template <class T>
-QueryResultFuture DatabaseWorkerPool<T>::AsyncQuery(const char* sql)
+QueryCallback DatabaseWorkerPool<T>::AsyncQuery(const char* sql)
 {
     BasicStatementTask* task = new BasicStatementTask(sql, true);
     // Store future result before enqueueing - task might get already processed and deleted before returning from this method
     QueryResultFuture result = task->GetFuture();
     Enqueue(task);
-    return result;
+    return QueryCallback(std::move(result));
 }
 
 template <class T>
-PreparedQueryResultFuture DatabaseWorkerPool<T>::AsyncQuery(PreparedStatement* stmt)
+QueryCallback DatabaseWorkerPool<T>::AsyncQuery(PreparedStatement* stmt)
 {
     PreparedStatementTask* task = new PreparedStatementTask(stmt, true);
     // Store future result before enqueueing - task might get already processed and deleted before returning from this method
     PreparedQueryResultFuture result = task->GetFuture();
     Enqueue(task);
-    return result;
+    return QueryCallback(std::move(result));
 }
 
 template <class T>
diff --git a/src/server/database/Database/DatabaseWorkerPool.h b/src/server/database/Database/DatabaseWorkerPool.h
index a082a9b6b0e..b195d2d6a28 100644
--- a/src/server/database/Database/DatabaseWorkerPool.h
+++ b/src/server/database/Database/DatabaseWorkerPool.h
@@ -19,7 +19,6 @@
 #define _DATABASEWORKERPOOL_H
 
 #include "Common.h"
-#include "QueryCallback.h"
 #include "MySQLConnection.h"
 #include "Transaction.h"
 #include "DatabaseWorker.h"
@@ -34,6 +33,8 @@
 #include <memory>
 #include <array>
 
+class QueryCallback;
+
 class PingOperation : public SQLOperation
 {
     //! Operation for idle delaythreads
@@ -192,12 +193,12 @@ class DatabaseWorkerPool
 
         //! Enqueues a query in string format that will set the value of the QueryResultFuture return object as soon as the query is executed.
         //! The return value is then processed in ProcessQueryCallback methods.
-        QueryResultFuture AsyncQuery(const char* sql);
+        QueryCallback AsyncQuery(const char* sql);
 
         //! Enqueues a query in string format -with variable args- that will set the value of the QueryResultFuture return object as soon as the query is executed.
         //! The return value is then processed in ProcessQueryCallback methods.
         template<typename Format, typename... Args>
-        QueryResultFuture AsyncPQuery(Format&& sql, Args&&... args)
+        QueryCallback AsyncPQuery(Format&& sql, Args&&... args)
         {
             return AsyncQuery(Trinity::StringFormat(std::forward<Format>(sql), std::forward<Args>(args)...).c_str());
         }
@@ -205,7 +206,7 @@ class DatabaseWorkerPool
         //! Enqueues a query in prepared format that will set the value of the PreparedQueryResultFuture return object as soon as the query is executed.
         //! The return value is then processed in ProcessQueryCallback methods.
         //! Statement must be prepared with CONNECTION_ASYNC flag.
-        PreparedQueryResultFuture AsyncQuery(PreparedStatement* stmt);
+        QueryCallback AsyncQuery(PreparedStatement* stmt);
 
         //! Enqueues a vector of SQL operations (can be both adhoc and prepared) that will set the value of the QueryResultHolderFuture
         //! return object as soon as the query is executed.
diff --git a/src/server/database/Database/QueryCallback.cpp b/src/server/database/Database/QueryCallback.cpp
index f88ad7a6e47..8850f87b20a 100644
--- a/src/server/database/Database/QueryCallback.cpp
+++ b/src/server/database/Database/QueryCallback.cpp
@@ -18,115 +18,186 @@
 #include "QueryCallback.h"
 
 template<typename T>
+inline void Construct(T& t)
+{
+    new (&t) T();
+}
+
+template<typename T>
 inline void Destroy(T& t)
 {
     t.~T();
 }
 
 template<typename T>
-void DestroyActiveMember(T& obj)
+void ConstructActiveMember(T* obj)
+{
+    if (!obj->_isPrepared)
+        Construct(obj->_string);
+    else
+        Construct(obj->_prepared);
+}
+
+template<typename T>
+void DestroyActiveMember(T* obj)
 {
-    if (!obj._isPrepared)
-        Destroy(obj._string);
+    if (!obj->_isPrepared)
+        Destroy(obj->_string);
     else
-        Destroy(obj._prepared);
+        Destroy(obj->_prepared);
 }
 
 template<typename T>
-void MoveFrom(T& to, T&& from)
+void MoveFrom(T* to, T&& from)
 {
-    DestroyActiveMember(to);
-    to._isPrepared = from._isPrepared;
-    if (!to._isPrepared)
-        to._string = std::move(from._string);
+    ASSERT(to->_isPrepared == from._isPrepared);
+
+    if (!to->_isPrepared)
+        to->_string = std::move(from._string);
     else
-        to._prepared = std::move(from._prepared);
+        to->_prepared = std::move(from._prepared);
 }
 
-struct QueryCallbackNew::QueryCallbackData
+struct QueryCallback::QueryCallbackData
 {
 public:
-    friend class QueryCallbackNew;
+    friend class QueryCallback;
 
-    QueryCallbackData(std::function<void(QueryResult)>&& callback) : _string(std::move(callback)), _isPrepared(false) { }
-    QueryCallbackData(std::function<void(PreparedQueryResult)>&& callback) : _prepared(std::move(callback)), _isPrepared(true) { }
-    QueryCallbackData(QueryCallbackData&& right) { MoveFrom(*this, std::move(right)); }
-    QueryCallbackData& operator=(QueryCallbackData&& right) { MoveFrom(*this, std::move(right)); return *this; }
-    ~QueryCallbackData() { DestroyActiveMember(*this); }
+    QueryCallbackData(std::function<void(QueryCallback&, QueryResult)>&& callback) : _string(std::move(callback)), _isPrepared(false) { TC_LOG_ERROR(LOGGER_ROOT, "QueryCallbackData [%p]: Constructing from string query", (void*)this); }
+    QueryCallbackData(std::function<void(QueryCallback&, PreparedQueryResult)>&& callback) : _prepared(std::move(callback)), _isPrepared(true) { TC_LOG_ERROR(LOGGER_ROOT, "QueryCallbackData [%p]: Constructing from prepared query", (void*)this); }
+    QueryCallbackData(QueryCallbackData&& right)
+    {
+        _isPrepared = right._isPrepared;
+        ConstructActiveMember(this);
+        MoveFrom(this, std::move(right));
+    }
+    QueryCallbackData& operator=(QueryCallbackData&& right)
+    {
+        if (this != &right)
+        {
+            if (_isPrepared != right._isPrepared)
+            {
+                DestroyActiveMember(this);
+                _isPrepared = right._isPrepared;
+                ConstructActiveMember(this);
+            }
+            MoveFrom(this, std::move(right));
+        }
+        return *this;
+    }
+    ~QueryCallbackData() { DestroyActiveMember(this); }
 
 private:
     QueryCallbackData(QueryCallbackData const&) = delete;
     QueryCallbackData& operator=(QueryCallbackData const&) = delete;
 
-    template<typename T> friend void MoveFrom(T& to, T&& from);
-    template<typename T> friend void DestroyActiveMember(T& obj);
+    template<typename T> friend void ConstructActiveMember(T* obj);
+    template<typename T> friend void DestroyActiveMember(T* obj);
+    template<typename T> friend void MoveFrom(T* to, T&& from);
 
     union
     {
-        std::function<void(QueryResult)> _string;
-        std::function<void(PreparedQueryResult)> _prepared;
+        std::function<void(QueryCallback&, QueryResult)> _string;
+        std::function<void(QueryCallback&, PreparedQueryResult)> _prepared;
     };
     bool _isPrepared;
 };
 
-QueryCallbackNew::QueryCallbackNew(std::future<QueryResult>&& result) : _string(std::move(result)), _isPrepared(false)
+QueryCallback::QueryCallback(std::future<QueryResult>&& result) : _string(std::move(result)), _isPrepared(false)
 {
 }
 
-QueryCallbackNew::QueryCallbackNew(std::future<PreparedQueryResult>&& result) : _prepared(std::move(result)), _isPrepared(true)
+QueryCallback::QueryCallback(std::future<PreparedQueryResult>&& result) : _prepared(std::move(result)), _isPrepared(true)
 {
 }
 
-QueryCallbackNew::QueryCallbackNew(QueryCallbackNew&& right)
+QueryCallback::QueryCallback(QueryCallback&& right)
 {
-    MoveFrom(*this, std::move(right));
+    _isPrepared = right._isPrepared;
+    ConstructActiveMember(this);
+    MoveFrom(this, std::move(right));
     _callbacks = std::move(right._callbacks);
 }
 
-QueryCallbackNew& QueryCallbackNew::operator=(QueryCallbackNew&& right)
+QueryCallback& QueryCallback::operator=(QueryCallback&& right)
 {
-    MoveFrom(*this, std::move(right));
-    _callbacks = std::move(right._callbacks);
+    if (this != &right)
+    {
+        if (_isPrepared != right._isPrepared)
+        {
+            DestroyActiveMember(this);
+            _isPrepared = right._isPrepared;
+            ConstructActiveMember(this);
+        }
+        MoveFrom(this, std::move(right));
+        _callbacks = std::move(right._callbacks);
+    }
     return *this;
 }
 
-QueryCallbackNew::~QueryCallbackNew()
+QueryCallback::~QueryCallback()
 {
-    DestroyActiveMember(*this);
+    DestroyActiveMember(this);
 }
 
-QueryCallbackNew&& QueryCallbackNew::WithCallback(std::function<void(QueryResult)>&& callback)
+QueryCallback&& QueryCallback::WithCallback(std::function<void(QueryResult)>&& callback)
+{
+    return WithChainingCallback([callback](QueryCallback& /*this*/, QueryResult result) { callback(std::move(result)); });
+}
+
+QueryCallback&& QueryCallback::WithPreparedCallback(std::function<void(PreparedQueryResult)>&& callback)
+{
+    return WithChainingPreparedCallback([callback](QueryCallback& /*this*/, PreparedQueryResult result) { callback(std::move(result)); });
+}
+
+QueryCallback&& QueryCallback::WithChainingCallback(std::function<void(QueryCallback&, QueryResult)>&& callback)
 {
     ASSERT(!_callbacks.empty() || !_isPrepared, "Attempted to set callback function for string query on a prepared async query");
     _callbacks.emplace(std::move(callback));
     return std::move(*this);
 }
 
-QueryCallbackNew&& QueryCallbackNew::WithPreparedCallback(std::function<void(PreparedQueryResult)>&& callback)
+QueryCallback&& QueryCallback::WithChainingPreparedCallback(std::function<void(QueryCallback&, PreparedQueryResult)>&& callback)
 {
     ASSERT(!_callbacks.empty() || _isPrepared, "Attempted to set callback function for prepared query on a string async query");
     _callbacks.emplace(std::move(callback));
     return std::move(*this);
 }
 
-QueryCallbackNew::Status QueryCallbackNew::InvokeIfReady()
+void QueryCallback::SetNextQuery(QueryCallback&& next)
+{
+    MoveFrom(this, std::move(next));
+}
+
+QueryCallback::Status QueryCallback::InvokeIfReady()
 {
     QueryCallbackData& callback = _callbacks.front();
+    auto checkStateAndReturnCompletion = [this]()
+    {
+        _callbacks.pop();
+        bool hasNext = !_isPrepared ? _string.valid() : _prepared.valid();
+        if (_callbacks.empty())
+        {
+            ASSERT(!hasNext);
+            return Completed;
+        }
+
+        // abort chain
+        if (!hasNext)
+            return Completed;
+
+        ASSERT(_isPrepared == _callbacks.front()._isPrepared);
+        return NextStep;
+    };
+
     if (!_isPrepared)
     {
         if (_string.valid() && _string.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
         {
-            std::function<void(QueryResult)> cb(std::move(callback._string));
-            cb(_string.get());
-            _callbacks.pop();
-            if (_callbacks.empty())
-            {
-                ASSERT(!_isPrepared ? !_string.valid() : !_prepared.valid());
-                return Completed;
-            }
-
-            ASSERT(_isPrepared == _callbacks.front()._isPrepared);
-            return NextStep;
+            std::future<QueryResult> f(std::move(_string));
+            std::function<void(QueryCallback&, QueryResult)> cb(std::move(callback._string));
+            cb(*this, f.get());
+            return checkStateAndReturnCompletion();
         }
     }
     else
@@ -134,17 +205,9 @@ QueryCallbackNew::Status QueryCallbackNew::InvokeIfReady()
         if (_prepared.valid() && _prepared.wait_for(std::chrono::seconds(0)) == std::future_status::ready)
         {
             std::future<PreparedQueryResult> f(std::move(_prepared));
-            std::function<void(PreparedQueryResult)> cb(std::move(callback._prepared));
-            cb(_prepared.get());
-            _callbacks.pop();
-            if (_callbacks.empty())
-            {
-                ASSERT(!_isPrepared ? !_string.valid() : !_prepared.valid());
-                return Completed;
-            }
-
-            ASSERT(_isPrepared == _callbacks.front()._isPrepared);
-            return NextStep;
+            std::function<void(QueryCallback&, PreparedQueryResult)> cb(std::move(callback._prepared));
+            cb(*this, f.get());
+            return checkStateAndReturnCompletion();
         }
     }
 
diff --git a/src/server/database/Database/QueryCallback.h b/src/server/database/Database/QueryCallback.h
index 6c4a8a81b4e..f9c93000da7 100644
--- a/src/server/database/Database/QueryCallback.h
+++ b/src/server/database/Database/QueryCallback.h
@@ -18,27 +18,26 @@
 #ifndef _QUERY_CALLBACK_H
 #define _QUERY_CALLBACK_H
 
-#include <future>
 #include "QueryResult.h"
+#include <future>
 
-typedef std::future<QueryResult> QueryResultFuture;
-typedef std::promise<QueryResult> QueryResultPromise;
-typedef std::future<PreparedQueryResult> PreparedQueryResultFuture;
-typedef std::promise<PreparedQueryResult> PreparedQueryResultPromise;
-
-#define CALLBACK_STAGE_INVALID uint8(-1)
-
-class TC_DATABASE_API QueryCallbackNew
+class TC_DATABASE_API QueryCallback
 {
 public:
-    explicit QueryCallbackNew(std::future<QueryResult>&& result);
-    explicit QueryCallbackNew(std::future<PreparedQueryResult>&& result);
-    QueryCallbackNew(QueryCallbackNew&& right);
-    QueryCallbackNew& operator=(QueryCallbackNew&& right);
-    ~QueryCallbackNew();
+    explicit QueryCallback(std::future<QueryResult>&& result);
+    explicit QueryCallback(std::future<PreparedQueryResult>&& result);
+    QueryCallback(QueryCallback&& right);
+    QueryCallback& operator=(QueryCallback&& right);
+    ~QueryCallback();
+
+    QueryCallback&& WithCallback(std::function<void(QueryResult)>&& callback);
+    QueryCallback&& WithPreparedCallback(std::function<void(PreparedQueryResult)>&& callback);
+
+    QueryCallback&& WithChainingCallback(std::function<void(QueryCallback&, QueryResult)>&& callback);
+    QueryCallback&& WithChainingPreparedCallback(std::function<void(QueryCallback&, PreparedQueryResult)>&& callback);
 
-    QueryCallbackNew&& WithCallback(std::function<void(QueryResult)>&& callback);
-    QueryCallbackNew&& WithPreparedCallback(std::function<void(PreparedQueryResult)>&& callback);
+    // Moves std::future from next to this object
+    void SetNextQuery(QueryCallback&& next);
 
     enum Status
     {
@@ -50,11 +49,12 @@ public:
     Status InvokeIfReady();
 
 private:
-    QueryCallbackNew(QueryCallbackNew const& right) = delete;
-    QueryCallbackNew& operator=(QueryCallbackNew const& right) = delete;
+    QueryCallback(QueryCallback const& right) = delete;
+    QueryCallback& operator=(QueryCallback const& right) = delete;
 
-    template<typename T> friend void MoveFrom(T& to, T&& from);
-    template<typename T> friend void DestroyActiveMember(T& obj);
+    template<typename T> friend void ConstructActiveMember(T* obj);
+    template<typename T> friend void DestroyActiveMember(T* obj);
+    template<typename T> friend void MoveFrom(T* to, T&& from);
 
     union
     {
@@ -67,182 +67,4 @@ private:
     std::queue<QueryCallbackData, std::list<QueryCallbackData>> _callbacks;
 };
 
-template <typename Result, typename ParamType, bool chain = false>
-class QueryCallback
-{
-    public:
-        QueryCallback() : _param(), _stage(chain ? 0 : CALLBACK_STAGE_INVALID)  { }
-
-        //! The parameter of this function should be a resultset returned from either .AsyncQuery or .AsyncPQuery
-        void SetFutureResult(std::future<Result> value)
-        {
-            _result = std::move(value);
-        }
-
-        std::future<Result>& GetFutureResult()
-        {
-            return _result;
-        }
-
-        bool IsReady()
-        {
-            return _result.valid() && _result.wait_for(std::chrono::seconds(0)) == std::future_status::ready;
-        }
-
-        void GetResult(Result& res)
-        {
-            res = _result.get();
-        }
-
-        void FreeResult()
-        {
-            // Nothing to do here, the constructor of std::future will take care of the cleanup
-        }
-
-        void SetParam(ParamType value)
-        {
-            _param = value;
-        }
-
-        ParamType GetParam()
-        {
-            return _param;
-        }
-
-        //! Resets the stage of the callback chain
-        void ResetStage()
-        {
-            if (!chain)
-                return;
-
-            _stage = 0;
-        }
-
-        //! Advances the callback chain to the next stage, so upper level code can act on its results accordingly
-        void NextStage()
-        {
-            if (!chain)
-                return;
-
-            ++_stage;
-        }
-
-        //! Returns the callback stage (or CALLBACK_STAGE_INVALID if invalid)
-        uint8 GetStage()
-        {
-            return _stage;
-        }
-
-        //! Resets all underlying variables (param, result and stage)
-        void Reset()
-        {
-            SetParam(ParamType());
-            FreeResult();
-            ResetStage();
-        }
-
-    private:
-        std::future<Result> _result;
-        ParamType _param;
-        uint8 _stage;
-
-        QueryCallback(QueryCallback const& right) = delete;
-        QueryCallback& operator=(QueryCallback const& right) = delete;
-};
-
-template <typename Result, typename ParamType1, typename ParamType2, bool chain = false>
-class QueryCallback_2
-{
-    public:
-        QueryCallback_2() : _stage(chain ? 0 : CALLBACK_STAGE_INVALID) { }
-
-        //! The parameter of this function should be a resultset returned from either .AsyncQuery or .AsyncPQuery
-        void SetFutureResult(std::future<Result> value)
-        {
-            _result = std::move(value);
-        }
-
-        std::future<Result>& GetFutureResult()
-        {
-            return _result;
-        }
-
-        bool IsReady()
-        {
-            return _result.valid() && _result.wait_for(std::chrono::seconds(0)) == std::future_status::ready;
-        }
-
-        void GetResult(Result& res)
-        {
-            res = _result.get();
-        }
-
-        void FreeResult()
-        {
-            // Nothing to do here, the constructor of std::future will take care of the cleanup
-        }
-
-        void SetFirstParam(ParamType1 value)
-        {
-            _param_1 = value;
-        }
-
-        void SetSecondParam(ParamType2 value)
-        {
-            _param_2 = value;
-        }
-
-        ParamType1 GetFirstParam()
-        {
-            return _param_1;
-        }
-
-        ParamType2 GetSecondParam()
-        {
-            return _param_2;
-        }
-
-        //! Resets the stage of the callback chain
-        void ResetStage()
-        {
-            if (!chain)
-                return;
-
-            _stage = 0;
-        }
-
-        //! Advances the callback chain to the next stage, so upper level code can act on its results accordingly
-        void NextStage()
-        {
-            if (!chain)
-                return;
-
-            ++_stage;
-        }
-
-        //! Returns the callback stage (or CALLBACK_STAGE_INVALID if invalid)
-        uint8 GetStage()
-        {
-            return _stage;
-        }
-
-        //! Resets all underlying variables (param, result and stage)
-        void Reset()
-        {
-            SetFirstParam(NULL);
-            SetSecondParam(NULL);
-            FreeResult();
-            ResetStage();
-        }
-
-    private:
-        std::future<Result> _result;
-        ParamType1 _param_1;
-        ParamType2 _param_2;
-        uint8 _stage;
-
-        QueryCallback_2(QueryCallback_2 const& right) = delete;
-        QueryCallback_2& operator=(QueryCallback_2 const& right) = delete;
-};
-
 #endif // _QUERY_CALLBACK_H
diff --git a/src/server/database/Database/QueryCallbackProcessor.cpp b/src/server/database/Database/QueryCallbackProcessor.cpp
index 0eaa1c2352c..9f8b8fc4ad9 100644
--- a/src/server/database/Database/QueryCallbackProcessor.cpp
+++ b/src/server/database/Database/QueryCallbackProcessor.cpp
@@ -27,15 +27,22 @@ QueryCallbackProcessor::~QueryCallbackProcessor()
 {
 }
 
-void QueryCallbackProcessor::AddQuery(QueryCallbackNew&& query)
+void QueryCallbackProcessor::AddQuery(QueryCallback&& query)
 {
     _callbacks.emplace_back(std::move(query));
 }
 
 void QueryCallbackProcessor::ProcessReadyQueries()
 {
-    _callbacks.erase(std::remove_if(_callbacks.begin(), _callbacks.end(), [](QueryCallbackNew& callback)
+    if (_callbacks.empty())
+        return;
+
+    std::vector<QueryCallback> updateCallbacks{ std::move(_callbacks) };
+
+    updateCallbacks.erase(std::remove_if(updateCallbacks.begin(), updateCallbacks.end(), [](QueryCallback& callback)
     {
-        return callback.InvokeIfReady() == QueryCallbackNew::Completed;
-    }), _callbacks.end());
+        return callback.InvokeIfReady() == QueryCallback::Completed;
+    }), updateCallbacks.end());
+
+    _callbacks.insert(_callbacks.end(), std::make_move_iterator(updateCallbacks.begin()), std::make_move_iterator(updateCallbacks.end()));
 }
diff --git a/src/server/database/Database/QueryCallbackProcessor.h b/src/server/database/Database/QueryCallbackProcessor.h
index 08ae3d15693..0b06fd8fc27 100644
--- a/src/server/database/Database/QueryCallbackProcessor.h
+++ b/src/server/database/Database/QueryCallbackProcessor.h
@@ -21,7 +21,7 @@
 #include "Define.h"
 #include <vector>
 
-class QueryCallbackNew;
+class QueryCallback;
 
 class TC_DATABASE_API QueryCallbackProcessor
 {
@@ -29,14 +29,14 @@ public:
     QueryCallbackProcessor();
     ~QueryCallbackProcessor();
 
-    void AddQuery(QueryCallbackNew&& query);
+    void AddQuery(QueryCallback&& query);
     void ProcessReadyQueries();
 
 private:
     QueryCallbackProcessor(QueryCallbackProcessor const&) = delete;
     QueryCallbackProcessor& operator=(QueryCallbackProcessor const&) = delete;
 
-    std::vector<QueryCallbackNew> _callbacks;
+    std::vector<QueryCallback> _callbacks;
 };
 
 #endif // QueryCallbackProcessor_h__