Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 146 insertions, 0 deletions

diff --git a/include/framework/gate.hxx b/include/framework/gate.hxx
new file mode 100644
index 000000000..ab9f81c24
--- /dev/null
+++ b/include/framework/gate.hxx
@@ -0,0 +1,146 @@
+/* -*- 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 .
+ */
+
+#pragma once
+
+#include <mutex>
+#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!
+            std::unique_lock 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!
+            std::unique_lock 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!
+            std::unique_lock 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.unlock();
+                // Wait for opening gate...
+                m_aPassage.wait();
+            }
+        }
+
+    //  private member
+
+    private:
+
+        std::mutex          m_aAccessLock;
+        ::osl::Condition    m_aPassage;
+        bool                m_bClosed;
+
+};      //  class Gate
+
+}       //  namespace framework
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */