Library: thread self recognition feature defined (#1054)

src/backend/thread-wrapper.hpp

@@ -80,7 +80,7 @@ namespace backend {
    * # failures in the thread function
    * The operation started in the new thread is protected by a top-level catch block.
    * Error states or caught exceptions can be propagated through the lumiera_error
-   * state flag, when using the \c join() facility. By invoking \join().maybeThrow()
+   * state flag, when using ThreadJoinable::join(). By invoking `join().maybeThrow()`
    * on a join-able thread, exceptions can be propagated.
    * @note any errorstate or caught exception detected on termination of a standard
    * async Thread is considered a violation of policy and will result in emergency
@@ -221,6 +221,13 @@ namespace backend {
                           ////////////////////////////////////////////////////////TICKET #1054 : consider to call safeguard here, to ensure this is called from within the thread
           lumiera_thread_sync ();
         }
+      
+    protected:
+      bool
+      invokedWithinThread()
+        {
+          UNIMPLEMENTED ("thread self recognition");
+        }
     };
   
   

tests/backend/thread-wrapper-join-test.cpp

@@ -24,10 +24,8 @@
 #include "lib/test/run.hpp"
 #include "lib/test/test-helper.hpp"
 
-#include "lib/symbol.hpp"
 #include "backend/thread-wrapper.hpp"
 #include "lib/error.hpp"
-#include "lib/sync.hpp"
 
 #include <functional>
 
@@ -126,7 +124,7 @@ namespace test {
                                 , bind (&ThreadWrapperJoin_test::theAction, this, DESTRUCTION_CODE)
                                 );
           
-          CHECK (!thread2.join().isValid() ); // can check success without throwing
+          CHECK (not thread2.join().isValid()); // can check success without throwing
         }
     };
   

tests/backend/thread-wrapper-self-recognition-test.cpp

@@ -0,0 +1,90 @@
+/*
+  ThreadWrapperSelfRecognitionTest(Test)  -  detect when code is running within a thread
+
+  Copyright (C)         Lumiera.org
+    2017,               Hermann Vosseler <Ichthyostega@web.de>
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License as
+  published by the Free Software Foundation; either version 2 of
+  the License, or (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+* *****************************************************/
+
+
+#include "lib/test/run.hpp"
+#include "lib/test/test-helper.hpp"
+
+#include "backend/thread-wrapper.hpp"
+#include "lib/error.hpp"
+
+using test::Test;
+
+
+
+namespace backend {
+namespace test {
+  
+  using lumiera::error::LUMIERA_ERROR_LOGIC;
+  namespace {
+    
+    class TestThread
+      : Thread
+      {
+        void
+        doIt()
+          {
+            CHECK (invocation_happens_within_this_thread());
+          }
+        
+        public:
+          TestThread()
+            : Thread{"test Thread self recognition", [&]() { doIt(); }}
+            { }
+          
+          bool
+          invocation_happens_within_this_thread()
+            {
+              return invokedWithinThread();
+            }
+      };
+    
+  }
+  
+  
+  /******************************************************//**
+   * @test verify the ability of a thread to detect code
+   *       executing within the thread itself.
+   * 
+   * @see Thread::invokedWithinThread()
+   * @see proc::control::DispatcherLoop::stateIsSynched()
+   */
+  class ThreadWrapperSelfRecognitionTest_test : public Test
+    {
+      
+      virtual void
+      run (Arg)
+        {
+          TestThread testThread;
+          
+          CHECK (not testThread.invocation_happens_within_this_thread());
+        }
+    };
+  
+  
+  
+  /** Register this test class... */
+  LAUNCHER (ThreadWrapperSelfRecognitionTest_test, "function common");
+  
+  
+  
+}} // namespace backend::test