[10865] Make DB code thread-safe. Original patch by Machiavelli and Kero99.

Signed-off-by: Ambal <pogrebniak@gala.net>

src/shared/Database/DatabaseMysql.cpp

@@ -264,6 +264,8 @@ bool DatabaseMysql::Execute(const char *sql)
     // don't use queued execution if it has not been initialized
     if (!m_threadBody) return DirectExecute(sql);
 
+    ACE_Guard<ACE_Thread_Mutex> _lock(nMutex);
+
     tranThread = ACE_Based::Thread::current();              // owner of this transaction
     TransactionQueues::iterator i = m_tranQueues.find(tranThread);
     if (i != m_tranQueues.end() && i->second != NULL)
@@ -341,6 +343,8 @@ bool DatabaseMysql::BeginTransaction()
         return true;                                        // transaction started
     }
 
+    ACE_Guard<ACE_Thread_Mutex> _lock(nMutex);
+
     tranThread = ACE_Based::Thread::current();              // owner of this transaction
     TransactionQueues::iterator i = m_tranQueues.find(tranThread);
     if (i != m_tranQueues.end() && i->second != NULL)
@@ -369,16 +373,18 @@ bool DatabaseMysql::CommitTransaction()
         return _res;
     }
 
+    ACE_Guard<ACE_Thread_Mutex> _lock(nMutex);
+
     tranThread = ACE_Based::Thread::current();
     TransactionQueues::iterator i = m_tranQueues.find(tranThread);
     if (i != m_tranQueues.end() && i->second != NULL)
     {
         m_threadBody->Delay(i->second);
-        i->second = NULL;
+        m_tranQueues.erase(i);
         return true;
     }
-    else
-        return false;
+
+    return false;
 }
 
 bool DatabaseMysql::RollbackTransaction()
@@ -397,13 +403,16 @@ bool DatabaseMysql::RollbackTransaction()
         return _res;
     }
 
+    ACE_Guard<ACE_Thread_Mutex> _lock(nMutex);
+
     tranThread = ACE_Based::Thread::current();
     TransactionQueues::iterator i = m_tranQueues.find(tranThread);
     if (i != m_tranQueues.end() && i->second != NULL)
     {
         delete i->second;
-        i->second = NULL;
+        m_tranQueues.erase(i);
     }
+
     return true;
 }
 

src/shared/Database/DatabaseMysql.h

@@ -65,7 +65,8 @@ class MANGOS_DLL_SPEC DatabaseMysql : public Database
         // must be call before finish thread run
         void ThreadEnd();
     private:
-        ACE_Thread_Mutex mMutex;
+        ACE_Thread_Mutex mMutex;        // For thread safe operations between core and mySQL server
+        ACE_Thread_Mutex nMutex;        // For thread safe operations on m_transQueues
 
         ACE_Based::Thread * tranThread;
 

src/shared/Database/SqlDelayThread.cpp

@@ -24,6 +24,14 @@ SqlDelayThread::SqlDelayThread(Database* db) : m_dbEngine(db), m_running(true)
 {
 }
 
+SqlDelayThread::~SqlDelayThread()
+{
+    //empty SQL queue before exiting
+    SqlOperation* s = NULL;
+    while (m_sqlQueue.next(s))
+        delete s;
+}
+
 void SqlDelayThread::run()
 {
     #ifndef DO_POSTGRESQL
@@ -39,14 +47,15 @@ void SqlDelayThread::run()
     {
         // if the running state gets turned off while sleeping
         // empty the queue before exiting
-
         ACE_Based::Thread::Sleep(loopSleepms);
+
         SqlOperation* s = NULL;
         while (m_sqlQueue.next(s))
         {
             s->Execute(m_dbEngine);
             delete s;
         }
+
         if((loopCounter++) >= pingEveryLoop)
         {
             loopCounter = 0;

src/shared/Database/SqlDelayThread.h

@@ -36,9 +36,9 @@ class SqlDelayThread : public ACE_Based::Runnable
         Database* m_dbEngine;                               ///< Pointer to used Database engine
         volatile bool m_running;
 
-        SqlDelayThread();
     public:
         SqlDelayThread(Database* db);
+        ~SqlDelayThread();
 
         ///< Put sql statement to delay queue
         bool Delay(SqlOperation* sql) { m_sqlQueue.add(sql); return true; }

src/shared/Database/SqlOperations.cpp

@@ -31,8 +31,10 @@ void SqlStatement::Execute(Database *db)
 
 void SqlTransaction::Execute(Database *db)
 {
+    ACE_Guard<ACE_Thread_Mutex> _lock(m_Mutex);
     if(m_queue.empty())
         return;
+
     db->DirectExecute("START TRANSACTION");
     while(!m_queue.empty())
     {
@@ -42,17 +44,20 @@ void SqlTransaction::Execute(Database *db)
         if(!db->DirectExecute(sql))
         {
             delete [] sql;
+
             db->DirectExecute("ROLLBACK");
             while(!m_queue.empty())
             {
                 delete [] (const_cast<char*>(m_queue.front()));
                 m_queue.pop();
             }
+
             return;
         }
 
         delete [] sql;
     }
+
     db->DirectExecute("COMMIT");
 }
 

src/shared/Database/SqlOperations.h

@@ -55,9 +55,18 @@ class SqlTransaction : public SqlOperation
 {
     private:
         std::queue<const char *> m_queue;
+        ACE_Thread_Mutex m_Mutex;
     public:
         SqlTransaction() {}
-        void DelayExecute(const char *sql) { m_queue.push(mangos_strdup(sql)); }
+        void DelayExecute(const char *sql)
+        {
+            char* _sql = mangos_strdup(sql);
+            if (_sql)
+            {
+                ACE_Guard<ACE_Thread_Mutex> _lock(m_Mutex);
+                m_queue.push(_sql);
+            }
+        }
         void Execute(Database *db);
 };
 

src/shared/LockedQueue.h

@@ -55,27 +55,18 @@ namespace ACE_Based
             //! Adds an item to the queue.
             void add(const T& item)
             {
-                lock();
-
-                //ASSERT(!this->_canceled);
-                // throw Cancellation_Exception();
-
+                ACE_Guard<LockType> g(this->_lock);
                 _queue.push_back(item);
-
-                unlock();
             }
 
             //! Gets the next result in the queue, if any.
             bool next(T& result)
             {
-                ACE_Guard<LockType> g(this->_lock);
+                ACE_GUARD_RETURN (LockType, g, this->_lock, false);
 
                 if (_queue.empty())
                     return false;
 
-                //ASSERT (!_queue.empty() || !this->_canceled);
-                // throw Cancellation_Exception();
-
                 result = _queue.front();
                 _queue.pop_front();
 
@@ -85,7 +76,7 @@ namespace ACE_Based
             template<class Checker>
             bool next(T& result, Checker& check)
             {
-                ACE_Guard<LockType> g(this->_lock);
+                ACE_GUARD_RETURN (LockType, g, this->_lock, false);
 
                 if (_queue.empty())
                     return false;
@@ -111,18 +102,14 @@ namespace ACE_Based
             //! Cancels the queue.
             void cancel()
             {
-                lock();
-
+                ACE_Guard<LockType> g(this->_lock);
                 _canceled = true;
-
-                unlock();
             }
 
             //! Checks if the queue is cancelled.
             bool cancelled()
             {
                 ACE_Guard<LockType> g(this->_lock);
-
                 return _canceled;
             }
 
@@ -137,6 +124,13 @@ namespace ACE_Based
             {
                 this->_lock.release();
             }
+            
+            ///! Checks if we're empty or not with locks held
+            bool empty()
+            {
+                ACE_Guard<LockType> g(this->_lock);
+                return _queue.empty();
+            }
     };
 }
 #endif

src/shared/revision_nr.h

@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "10864"
+ #define REVISION_NR "10865"
 #endif // __REVISION_NR_H__