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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed
+ * with this work for additional information regarding copyright
+ * ownership. The ASF licenses this file to you under the Apache
+ * License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_FRAMEWORK_INC_THREADHELP_GATE_HXX
+#define INCLUDED_FRAMEWORK_INC_THREADHELP_GATE_HXX
+
+#include <osl/mutex.hxx>
+#include <osl/conditn.hxx>
+
+namespace framework{
+
+/*-************************************************************************************************************
+ @short implement a gate to block multiple threads at the same time or unblock all
+ @descr A gate can be used as a negative-condition! You can open a "door" - wait() will not block ...
+ or you can close it - wait() blocks till open() is called again.
+ Then all currently waiting threads are running immediately - but new ones are blocked!
+
+ @attention To prevent us against wrong using, the default ctor, copy ctor and the =operator are marked private!
+
+ @devstatus ready to use
+*//*-*************************************************************************************************************/
+class Gate
+{
+
+ // public methods
+
+ public:
+
+ /*-****************************************************************************************************
+ @short ctor
+ @descr These initialize the object right as an open gate.
+ *//*-*****************************************************************************************************/
+ Gate()
+ : m_bClosed ( false )
+ {
+ open();
+ }
+
+ /*-****************************************************************************************************
+ @short dtor
+ @descr Is user forget it - we open the gate ...
+ blocked threads can running ... but I don't know
+ if it's right - we are destroyed yet!?
+ *//*-*****************************************************************************************************/
+ ~Gate()
+ {
+ open();
+ }
+ /*-****************************************************************************************************
+ @short copy-ctor
+ @descr Forbid copy construction
+ *//*-*****************************************************************************************************/
+ Gate(const Gate&) = delete;
+ /*-****************************************************************************************************
+ @short copy-assignment
+ @descr Forbid copy assigning
+ *//*-*****************************************************************************************************/
+ Gate& operator=(const Gate&) = delete;
+
+ /*-****************************************************************************************************
+ @short open the gate
+ @descr A wait() call will not block then.
+
+ @seealso method close()
+ *//*-*****************************************************************************************************/
+ void open()
+ {
+ // We must safe access to our internal member!
+ ::osl::MutexGuard aLock( m_aAccessLock );
+ // Set condition -> wait don't block any longer -> gate is open
+ m_aPassage.set();
+ // Check if operation was successful!
+ // Check returns false if condition isn't set => m_bClosed will be true then => we must return false; opening failed
+ m_bClosed = !m_aPassage.check();
+ }
+
+ /*-****************************************************************************************************
+ @short close the gate
+ @descr A wait() call will block then.
+
+ @seealso method open()
+ *//*-*****************************************************************************************************/
+ void close()
+ {
+ // We must safe access to our internal member!
+ ::osl::MutexGuard aLock( m_aAccessLock );
+ // Reset condition -> wait blocks now -> gate is closed
+ m_aPassage.reset();
+ // Check if operation was successful!
+ // Check returns false if condition was reset => m_bClosed will be true then => we can return true; closing ok
+ m_bClosed = !m_aPassage.check();
+ }
+
+ /*-****************************************************************************************************
+ @short must be called to pass the gate
+ @descr If gate "open" => wait() will not block.
+ If gate "closed" => wait() will block till somewhere open it again.
+
+ @seealso method wait()
+ @seealso method open()
+
+ *//*-*****************************************************************************************************/
+ void wait()
+ {
+ // We must safe access to our internal member!
+ ::osl::ClearableMutexGuard aLock( m_aAccessLock );
+ // If gate not closed - caller can pass it.
+ if( m_bClosed )
+ {
+ // Then we must release used access lock -
+ // because next call will block...
+ // and if we hold the access lock nobody else can use this object without a deadlock!
+ aLock.clear();
+ // Wait for opening gate...
+ m_aPassage.wait();
+ }
+ }
+
+ // private member
+
+ private:
+
+ ::osl::Mutex m_aAccessLock;
+ ::osl::Condition m_aPassage;
+ bool m_bClosed;
+
+}; // class Gate
+
+} // namespace framework
+
+#endif // INCLUDED_FRAMEWORK_INC_THREADHELP_GATE_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */