Initial commit

Lts/Plugins/AudioVideoManagement/Data/avm_exercise_context.h

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+/**
+  * @RDE_HEADER@
+  * AvmExerciseContext
+  * $Id$
+  * $HeadURL$
+  * $Author$
+  * Created by Christian Fröbel, NLSE, 2018-07-30
+  */
+
+#pragma once
+
+#include <map>
+#include <functional>
+#include <memory>
+
+namespace LtsSession
+{
+class LtsSessionDataDds;
+}
+
+namespace OperatorManagement
+{
+namespace Interface
+{
+class Dtc;
+}
+}
+
+namespace ExerciseManagement
+{
+namespace Interface
+{
+class Dtc;
+}
+}
+
+namespace InfrastructureManagement
+{
+namespace Interface
+{
+class Dtc;
+}
+}
+
+namespace AudioVideoManagement
+{
+
+namespace Interface
+{
+class Dtc;
+class Ftc;
+}
+
+class StreamNameMapping;
+
+/**
+ * For each Exercise -- as defined by its Id -- AvmExerciseContextManager manages
+ * an associated ExerciseContext. The ExerciseContext just holds all necessary entities.
+ * The idea is that any number of PluginInterface-instances with the same exerciseId
+ * share the same ExerciseContext.
+ * For example, all PluginInterface-instances for Exercise 42 can share the *same* Dtc or Ftc.
+ * Thus Dtc and Ftc are part of the ExerciseContext.
+ * 
+ * The lifetime of an ExerciseContext can be longer than the lifetime of a PluginInterface-instance.
+ * AvsSessionContext uses (references) entities from the ExerciseContext.
+ * This is ok as it is guaranteed that the lifetime of the ExerciseContext is at least as long
+ * as the lifetime of AvsSessionContext.
+ * Actually they have the same lifetime -- if an AvsSessionContext exists.
+ * 
+ * The difference is that there can be at most one AvsSessionContext at the same time.
+ * But there can be at most one ExerciseContext *for each* exerciseId at the same time.
+ * For the global exercise (exerciseId 0) there is never an AvsSessionContext.
+ * 
+ * The following picuture illustrates the lifetimes:
+ * 
+ * App1 (42)                            ---------         ---------
+ * App2 (42)                                        ---------               ---------
+ * App3 (35)                                                          =========
+ *                                      
+ * ExerciseContext (42)                 ---------   ---------------         ---------
+ * ExerciseContext (35)                                               =========
+ *                                      
+ * AvsSessionContext (42)               ---------   ---------------
+ * AvsSessionContext (35)                                             =========
+ *                                     
+ * PluginInterface-instance 1 (42)      ---------
+ * PluginInterface-instance 2 (42)                  ---------
+ * PluginInterface-instance 3 (42)                        ---------
+ * PluginInterface-instance 4 (35)                                    =========
+ * PluginInterface-instance 5 (42)                                          ---------
+ * 
+ * @see AvsSessionContext
+ * @author Christian Fröbel
+ */
+class AvmExerciseContextManager
+{
+public:
+  struct ExerciseContext;
+  
+  ~AvmExerciseContextManager();
+  
+  /**
+   * Don't use directly; use AvmExerciseContextHandle instead.
+   */
+  ///@{
+  ExerciseContext *acquire(int exerciseId, LtsSession::LtsSessionDataDds *session);
+  void release(int exerciseId, ExerciseContext *composite);
+  ///@}
+  
+private:
+  /**
+   * Small internal helper class in order to keep track of the refCount.
+   * Here, the refCount denotes the number of PluginInterface-Instances for the same Exercise.
+   */
+  struct RefCountedContext
+  {
+    explicit RefCountedContext(std::unique_ptr<ExerciseContext> &&context);
+    RefCountedContext(RefCountedContext &&) noexcept;
+    ~RefCountedContext();
+    
+    int                                refCount{1};
+    std::unique_ptr<ExerciseContext>   context;
+  };
+  
+  using ExerciseId = int;
+  std::map<ExerciseId, RefCountedContext>   m_activeContexts;
+};
+
+
+/**
+ * Helper class to automatically call AvmExerciseContextManager::acquire()
+ * and AvmExerciseContextManager::release() in the ctor and dtor respectively.
+ * Instances can be moved but not copied.
+ * 
+ * @author Christian Fröbel
+ */
+class AvmExerciseContextHandle
+{
+public:
+  AvmExerciseContextHandle();
+  AvmExerciseContextHandle(AvmExerciseContextManager *context, int exerciseId, LtsSession::LtsSessionDataDds *session);
+  
+  operator bool() const { return m_context.get(); }
+  
+  /** Only available when not in global Exercise */
+  StreamNameMapping *streamNameMapping() const;
+  
+  const std::shared_ptr<Interface::Dtc> &dtc() const;
+  const std::shared_ptr<Interface::Ftc> &ftc() const;
+  
+  OperatorManagement::Interface::Dtc *opmDtc() const;
+  ExerciseManagement::Interface::Dtc *exmDtc() const;
+  InfrastructureManagement::Interface::Dtc *ismDtc() const;
+
+
+private:
+  using Releaser = std::function<void (AvmExerciseContextManager::ExerciseContext *)>;
+  std::unique_ptr<AvmExerciseContextManager::ExerciseContext, Releaser>   m_context;
+};
+
+} // namespace AudioVideoManagement