Task #3696: Improved SharedMemory test

RTCP/InputProc/test/tSharedMemory.cc

 #include <lofar_config.h>
 #include "SharedMemory.h"
 #include <Common/LofarLogger.h>
+#include <Common/Thread/Thread.h>
+#include <unistd.h>
 
 using namespace LOFAR;
 using namespace RTCP;
 
+Semaphore semaphore;
+
+class A {
+public:
+  void creator() {
+    sleep(1);
+
+    SharedMemoryArena m( 0x12345678, 1024, SharedMemoryArena::CREATE, 0 );
+
+    LOG_INFO("Memory area created");
+
+    // wait for done
+    semaphore.down();
+  }
+
+  void reader() {
+    LOG_INFO("Waiting for memory area");
+
+    SharedMemoryArena m( 0x12345678, 1024, SharedMemoryArena::READ, 2 );
+
+    LOG_INFO("Memory area attached");
+
+    // signal done
+    semaphore.up();
+  }
+};
+
 int main( int, char **argv ) {
   INIT_LOGGER( argv[0] );
 
@@ -14,4 +43,72 @@ int main( int, char **argv ) {
 
     SharedMemoryArena m( 0x12345678, 1024, SharedMemoryArena::CREATE, 0 );
   }
+
+  /* Create a shared memory region and access it */
+  {
+    LOG_INFO("Create shared memory region and access it");
+
+    SharedMemoryArena x( 0x12345678, 1024, SharedMemoryArena::CREATE, 0 );
+
+    SharedMemoryArena y( 0x12345678, 1024, SharedMemoryArena::READ, 0 );
+  }
+
+  /* Access a non-existing shared memory region */
+  {
+    LOG_INFO("Access a non-existing shared memory region");
+
+    bool caught_exception = false;
+
+    try {
+      SharedMemoryArena y( 0x12345678, 1024, SharedMemoryArena::READ, 0 );
+    } catch(SystemCallException &e) {
+      caught_exception = true;
+    }
+
+    ASSERT(caught_exception);
+  }
+
+  /* Access a non-existing shared memory region, with timeout */
+  {
+    LOG_INFO("Access a non-existing shared memory region");
+
+    bool caught_exception = false;
+
+    try {
+      SharedMemoryArena y( 0x12345678, 1024, SharedMemoryArena::READ, 1 );
+    } catch(SharedMemoryArena::TimeOutException &e) {
+      caught_exception = true;
+    }
+
+    ASSERT(caught_exception);
+  }
+
+#ifdef USE_THREADS
+  LOG_INFO("Debugging concurrent access");
+
+  {
+    /* Start reader before creator */
+    A obj;
+
+    // delayed creation of memory region
+    Thread creator(&obj, &A::creator);
+
+    // wait for access
+    obj.reader();
+  }
+#endif
+
+  /* Check whether memory access works as expected */
+  {
+    LOG_INFO("Checking memory access through SharedStruct");
+
+    SharedStruct<int> writer( 0x12345678, true, 0 );
+
+    SharedStruct<int> reader( 0x12345678, false, 0 );
+
+    writer.get() = 42;
+    ASSERT( reader.get() == 42 );
+  }
+
+  return 0;
 }