added Poco::Data::Session::isGood()

Data/MySQL/include/Poco/Data/MySQL/MySQLException.h

@@ -44,6 +44,9 @@ public:
 	MySQLException(const MySQLException& exc);
 		/// Creates MySQLException.
 
+	MySQLException(const std::string& msg, int code);
+		/// Creates MySQLException.
+
 	~MySQLException() noexcept;
 		/// Destroys MySQLexception.
 

Data/MySQL/include/Poco/Data/MySQL/SessionHandle.h

@@ -70,6 +70,9 @@ public:
 	void reset();
 		/// Reset connection with dababase and clears session state, but without disconnecting
 
+	bool ping();
+		/// Checks if the connection is alive.
+
 	operator MYSQL* ();
 
 private:

Data/MySQL/include/Poco/Data/MySQL/SessionImpl.h

@@ -73,6 +73,18 @@ public:
 	bool isConnected() const;
 		/// Returns true if connected, false otherwise.
 
+	bool isGood() const;
+		/// Returns true iff the database session is good.
+		/// For the session to be considered good:
+		///   - it must be connected
+		///   - and it's last error code must be 0,
+		///     or mysql_ping() must be okay.
+		///
+		/// Furthermore, if the "failIfInnoReadOnly" property
+		/// has been set to true, the innodb_read_only setting
+		/// must be false. The flag is only checked if the
+		/// session has a non-zero error code.
+
 	void setConnectionTimeout(std::size_t timeout);
 		/// Sets the session connection timeout value.
 
@@ -120,6 +132,20 @@ public:
 	Poco::Any getInsertId(const std::string&) const;
 		/// Get insert id
 
+	void setFailIfInnoReadOnly(const std::string&, bool value);
+		/// Sets the "failIfInnoReadOnly" feature. If set, isGood() will
+		/// return false if the database is in read-only mode.
+
+	bool getFailIfInnoReadOnly(const std::string&) const;
+		/// Returns the state of the "failIfInnoReadOnly" feature.
+
+	void setLastError(int err);
+		/// Sets an error code. If a non-zero error code is set, the session
+		/// is considered bad.
+
+	int getLastError() const;
+		/// Returns the last set error code.
+
 	SessionHandle& handle();
 		// Get handle
 
@@ -158,7 +184,9 @@ private:
 	mutable SessionHandle _handle;
 	bool                  _connected;
 	bool                  _inTransaction;
+	bool                  _failIfInnoReadOnly;
 	std::size_t           _timeout;
+	mutable int           _lastError;
 	Poco::FastMutex       _mutex;
 };
 
@@ -183,6 +211,30 @@ inline Poco::Any SessionImpl::getInsertId(const std::string&) const
 }
 
 
+inline void SessionImpl::setFailIfInnoReadOnly(const std::string&, bool value)
+{
+	_failIfInnoReadOnly = value;
+}
+
+
+inline bool SessionImpl::getFailIfInnoReadOnly(const std::string&) const
+{
+	return _failIfInnoReadOnly;
+}
+
+
+inline void SessionImpl::setLastError(int err)
+{
+	_lastError = err;
+}
+
+
+inline int SessionImpl::getLastError() const
+{
+	return _lastError;
+}
+
+
 inline SessionHandle& SessionImpl::handle()
 {
 	return _handle;
@@ -207,12 +259,6 @@ inline bool SessionImpl::isTransactionIsolation(Poco::UInt32 ti) const
 }
 
 
-inline bool SessionImpl::isConnected() const
-{
-	return _connected;
-}
-	
-
 inline std::size_t SessionImpl::getConnectionTimeout() const
 {
 	return _timeout;

Data/MySQL/src/MySQLException.cpp

@@ -32,6 +32,11 @@ MySQLException::MySQLException(const MySQLException& exc) : Poco::Data::DataExce
 }
 
 
+MySQLException::MySQLException(const std::string& msg, int code) : Poco::Data::DataException(std::string("[MySQL]: ") + msg, code)
+{
+}
+
+
 MySQLException::~MySQLException() noexcept
 {
 }

Data/MySQL/src/MySQLStatementImpl.cpp

@@ -119,12 +119,21 @@ bool MySQLStatementImpl::canCompile() const
 
 void MySQLStatementImpl::compileImpl()
 {
+	try
+	{
 		_metadata.reset();
 		_stmt.prepare(toString());
 		_metadata.init(_stmt);
 
 		if (_metadata.columnsReturned() > 0)
 			_stmt.bindResult(_metadata.row());
+	}
+	catch (MySQLException& exc)
+	{
+		static_cast<SessionImpl&>(session()).setLastError(exc.code());
+		throw;
+	}
+	static_cast<SessionImpl&>(session()).setLastError(0);
 }
 
 
@@ -141,8 +150,17 @@ void MySQLStatementImpl::bindImpl()
 	}
 
 	_stmt.bindParams(_pBinder->getBindArray(), _pBinder->size());
+	try
+	{
 		_stmt.execute();
+	}
+	catch (MySQLException& exc)
+	{
+		static_cast<SessionImpl&>(session()).setLastError(exc.code());
+		throw;
+	}
 	_hasNext = NEXT_DONTKNOW;
+	static_cast<SessionImpl&>(session()).setLastError(0);
 }
 
 

Data/MySQL/src/SessionHandle.cpp

@@ -192,4 +192,11 @@ void SessionHandle::reset()
 }
 
 
+bool SessionHandle::ping()
+{
+	int rc = mysql_ping(_pHandle);
+	return rc == 0;
+}
+
+
 } } } // namespace Poco::Data::MySQL

Data/MySQL/src/SessionImpl.cpp

@@ -49,10 +49,13 @@ SessionImpl::SessionImpl(const std::string& connectionString, std::size_t loginT
 	_connector("MySQL"),
 	_handle(0),
 	_connected(false),
-	_inTransaction(false)
+	_inTransaction(false),
+	_failIfInnoReadOnly(false),
+	_lastError(0)
 {
 	addProperty("insertId", &SessionImpl::setInsertId, &SessionImpl::getInsertId);
 	setProperty("handle", static_cast<MYSQL*>(_handle));
+	addFeature("failIfInnoReadOnly", &SessionImpl::setFailIfInnoReadOnly, &SessionImpl::getFailIfInnoReadOnly);
 	open();
 }
 
@@ -266,6 +269,50 @@ void SessionImpl::reset()
 }
 
 
+inline bool SessionImpl::isConnected() const
+{
+	return _connected;
+}
+
+
+bool SessionImpl::isGood() const
+{
+	if (_connected)
+	{
+		if (_lastError)
+		{
+			if (_failIfInnoReadOnly)
+			{
+				try
+				{
+					int ro = 0;
+					if (0 == getSetting("innodb_read_only", ro))
+					{
+						_lastError = 0;
+						return true;
+					}
+				}
+				catch (...)
+				{
+				}
+				return false;
+			}
+			else
+			{
+				if (_handle.ping())
+				{
+					_lastError = 0;
+					return true;
+				}
+				return false;
+			}
+		}
+		else return true;
+	}
+	else return false;
+}
+
+
 void SessionImpl::close()
 {
 	if (_connected)

Data/include/Poco/Data/PooledSessionImpl.h

@@ -52,6 +52,7 @@ public:
 	void close();
 	void reset();
 	bool isConnected() const;
+	bool isGood() const;
 	void setConnectionTimeout(std::size_t timeout);
 	std::size_t getConnectionTimeout() const;
 	bool canTransact() const;

Data/include/Poco/Data/Session.h

@@ -218,6 +218,9 @@ public:
 	void reconnect();
 		/// Closes the session and opens it.
 
+	bool isGood();
+		/// Returns true iff the session is good and can be used, false otherwise.
+
 	void setLoginTimeout(std::size_t timeout);
 		/// Sets the session login timeout value.
 
@@ -350,6 +353,12 @@ inline void Session::reconnect()
 }
 
 
+inline bool Session::isGood()
+{
+	return _pImpl->isGood();
+}
+
+
 inline void Session::setLoginTimeout(std::size_t timeout)
 {
 	_pImpl->setLoginTimeout(timeout);

Data/include/Poco/Data/SessionImpl.h

@@ -77,6 +77,11 @@ public:
 	virtual bool isConnected() const = 0;
 		/// Returns true if session is connected, false otherwise.
 
+	virtual bool isGood() const;
+		/// Returns true if session is good and can be used, false otherwise.
+		///
+		/// The default implementation returns result of isConnected().
+
 	void setLoginTimeout(std::size_t timeout);
 		/// Sets the session login timeout value.
 

Data/src/PooledSessionImpl.cpp

@@ -66,6 +66,12 @@ bool PooledSessionImpl::isConnected() const
 }
 
 
+bool PooledSessionImpl::isGood() const
+{
+	return access()->isGood();
+}
+
+
 void PooledSessionImpl::setConnectionTimeout(std::size_t timeout)
 {
 	return access()->setConnectionTimeout(timeout);

Data/src/SessionImpl.cpp

@@ -49,4 +49,10 @@ void SessionImpl::setConnectionString(const std::string& connectionString)
 }
 
 
+bool SessionImpl::isGood() const
+{
+	return isConnected();
+}
+
+
 } } // namespace Poco::Data

Data/src/SessionPool.cpp

@@ -100,7 +100,7 @@ void SessionPool::purgeDeadSessions()
 	SessionList::iterator it = _idleSessions.begin();
 	for (; it != _idleSessions.end(); )
 	{
-		if (!(*it)->session()->isConnected())
+		if (!(*it)->session()->isGood())
 		{
 			it = _idleSessions.erase(it);
 			--_nSessions;
@@ -139,7 +139,7 @@ int SessionPool::dead()
 	SessionList::iterator itEnd = _activeSessions.end();
 	for (; it != itEnd; ++it)
 	{
-		if (!(*it)->session()->isConnected())
+		if (!(*it)->session()->isGood())
 			++count;
 	}
 
@@ -233,7 +233,7 @@ void SessionPool::putBack(PooledSessionHolderPtr pHolder)
 	SessionList::iterator it = std::find(_activeSessions.begin(), _activeSessions.end(), pHolder);
 	if (it != _activeSessions.end())
 	{
-		if (pHolder->session()->isConnected())
+		if (pHolder->session()->isGood())
 		{
 			pHolder->session()->reset();
 
@@ -271,7 +271,7 @@ void SessionPool::onJanitorTimer(Poco::Timer&)
 	SessionList::iterator it = _idleSessions.begin(); 
 	while (_nSessions > _minSessions && it != _idleSessions.end())
 	{
-		if ((*it)->idle() > _idleTime || !(*it)->session()->isConnected())
+		if ((*it)->idle() > _idleTime || !(*it)->session()->isGood())
 		{	
 			try	{ (*it)->session()->close(); }
 			catch (...) { }