WIP draft capturing mechanism implementation, using the new tools and helpers...

src/proc/control/command-mutation.hpp

@@ -37,6 +37,7 @@
 
 //#include "pre.hpp"
 #include "lib/error.hpp"
+#include "lib/bool-checkable.hpp"
 #include "proc/control/command-closure.hpp"
 #include "proc/control/memento-tie.hpp"
 
@@ -66,6 +67,7 @@ namespace control {
    * @todo Type-comment
    */
   class Mutation
+    : public lib::BoolCheckable<Mutation>
     {
       CmdFunctor func_;
       CmdClosure* clo_;
@@ -101,37 +103,24 @@ namespace control {
         }
       
       
-      /* == diagnostics == */
+      /** diagnostics */
-      typedef CmdClosure* Mutation::*_unspecified_bool_type;
-      
-      /** implicit conversion to "bool" */ 
-      operator _unspecified_bool_type()  const { return  isValid()? &Mutation::clo_ : 0; }  // never throws
-      bool operator! ()                  const { return !isValid(); }                      //  ditto
-      
       operator string()  const
         { 
           return isValid()? string (*clo_) : "Mutation(state missing)";
         }
       
-    protected:
       virtual bool
       isValid ()   const
         {
           return func_ && clo_;
         }
       
+    protected:
       void
       invoke (CmdFunctor & closedFunction)
         {
           closedFunction.getFun<void()>() ();
         }
-      
-      CmdClosure&
-      getClosure() ///< Interface for subclasses to access the bound parameters
-        {
-          REQUIRE (clo_, "Lifecycle error: function arguments not yet bound");
-          return *clo_;
-        }
     };
   
   
@@ -146,51 +135,24 @@ namespace control {
   class UndoMutation
     : public Mutation
     {
-      Mutation memento_;
+      Mutation captureMemento_;
       
     public:
-      template<typename SIG_undo, typename SIG_cap>
+      template<typename TIE>
-      UndoMutation (function<SIG_undo> const& undoFunc,
+      UndoMutation (TIE & mementoHolder)
-                    function<SIG_cap> const& captureFunc)
+        : Mutation (mementoHolder.tieUndoFunc())
-        : Mutation (undoFunc)
+        , captureMemento_(mementoHolder.tieCaptureFunc())
-        , memento_(captureFunc)
         { }
       
-#if false /////////////////////////////////////////////////TODO: remove after refactoring
-      UndoMutation (UndoMutation const& o)
-        : Mutation (*this)
-        , captureFunc_(o.captureFunc_)
-        , memento_(o.memento_->clone().get())
-        { }
-      
-      UndoMutation&
-      operator= (UndoMutation const& o)
-        {
-          Mutation::operator= (o);
-          captureFunc_ = o.captureFunc_;
-          memento_.reset(o.memento_->clone().get());
-          return *this;
-        }
-      
       
       virtual Mutation&
       close (CmdClosure& cmdClosure)
         {
-          REQUIRE (!memento_,    "Lifecycle error: already closed over the arguments");
+          Mutation::close(cmdClosure);
-          REQUIRE (captureFunc_, "Param error: not bound to a valid function");
+          captureMemento_.close(cmdClosure);
-          
-          // create a special state closure, which can later on store the captured undo state (memento)
-          scoped_ptr<MementoClosure> stateClosure (new MementoClosure (captureFunc_));
-          CmdFunctor closedCaptureFunc = cmdClosure.bindArguments(captureFunc_);
-          
-          // the undoFunc (within parent class) will retrieve an argument tuple extended by the memento
-          Mutation::close (stateClosure->decorate (cmdClosure));
-          
-          captureFunc_ = closedCaptureFunc;
-//          memento_.swap(stateClosure);
           return *this;
         }
-#endif      
+      
       
       Mutation&
       captureState ()
@@ -199,22 +161,16 @@ namespace control {
             throw lumiera::error::State ("need to bind function arguments prior to capturing undo state",
                                          LUMIERA_ERROR_UNBOUND_ARGUMENTS);
           
-          memento_();
+          captureMemento_();
           return *this;
         }
       
-      CmdClosure&
-      getMemento()
-        {
-          ASSERT (memento_, "Lifecycle error: need to close first");
-//          return *memento_;
-        }
       
     private:
       virtual bool
       isValid ()   const
         {
-//          return Mutation::isValid() && captureFunc_ && memento_;
+          return Mutation::isValid() && memento_;
         }
       
       

src/proc/control/memento-tie.hpp

@@ -28,7 +28,6 @@
  ** the "undo capture function" and the actual "undo function", by retrieving the
  ** memento data or memento object from the former and feeding it to the latter
  ** as an additional parameter, when the undo operation is invoked.
- ** //TODO
  **  
  ** @see CmdClosure
  ** @see UndoMutation
@@ -44,7 +43,7 @@
 //#include "pre.hpp"
 //#include "lib/meta/typelist.hpp"  ////////////////TODO include these??
 //#include "lib/meta/function.hpp"
-//#include "lib/meta/function-closure.hpp"
+#include "lib/meta/function-closure.hpp"
 //#include "lib/meta/function-erasure.hpp"
 //#include "lib/meta/tuple.hpp"
 #include "proc/control/command-signature.hpp"
@@ -52,7 +51,7 @@
 #include "lib/util.hpp"
 
 //#include <tr1/memory>
-//#include <tr1/functional>
+#include <tr1/functional>
 //#include <iostream> 
 //#include <string>
 
@@ -70,6 +69,7 @@ namespace control {
 //  using std::tr1::shared_ptr;
 //  using util::unConst;
   using std::string;
+  using lumiera::typelist::func::bindLast;
 //  using std::ostream;
 //  using std::tr1::function;
 //  using lumiera::typelist::FunctionSignature;
@@ -85,10 +85,10 @@ namespace control {
   
   /**
    *  Binding together state capturing and execution of the undo operation.
-   *  MementoTie itself is passive container object with a very specific type,
+   *  MementoTie itself is a passive container object with a very specific type,
    *  depending on the type of the operation arguments and the type of the memento.
    *  It is to be allocated within the ArgumentHolder of the command, thereby wrapping
-   *  or decorating the undo and capture function, setting up  the necessary bindings and
+   *  or decorating the undo and capture function, setting up the necessary bindings and
    *  closures, allowing them to cooperate behind the scenes to carry out the UNDO functionality.
    *  Through a reference to the MementoTie, the UndoMutation functor gets access to the prepared
    *  functions, storing them into generic containers (type erasure) for later invocation. 
@@ -109,20 +109,15 @@ namespace control {
       /** storage holding the captured state for undo */
       MEM memento_;
       
-      function<SIG> undo_;
+      bool isCaptured_;
-      function<SIG> capture_;
       
+      function<SIG_undo> undo_;
+      function<SIG_cap> capture_;
       
-      function<SIG>
+      void capture (MEM const& mementoVal)
-      buildFun()
         {
-//          PlaceholderTuple<SIG> tup;
+          memento_ = mementoVal;
-//          return tupleApplicator(tup).bind(origFun);
+          isCaptured_ = true;
-        }
-      
-      void capture ()
-        {
-          memento_ = capture();
         }
       
     public:
@@ -133,11 +128,58 @@ namespace control {
        */
       MementoTie (function<SIG_undo> const& undoFunc,
                   function<SIG_cap> const& captureFunc)
+        : memento_()
+        , isCaptured_(false)
+        , undo_(undoFunc)
+        , capture_(captureFunc)
         { }
       
-    };
       
-  ////////////////TODO currently just fleshing  out the API....
+      /** bind the undo function to the internal memento store within this object.
+       *  @return a functor, which, when invoked with the remaining arguments, will
+       *        automatically call #getState() to retrieve the current memento value.
+       *  @note similar to #getState(), the returned functor will throw
+       *        when the state capturing wasn't yet invoked
+       */
+      function<SIG>
+      tieUndoFunc()
+        {
+          using std::tr1::bind;
+          
+          return bindLast( undo_
+                         , bind (&MementoTie::getState, this)
+                         );
+        }
+      
+      /** bind the capturing function to the internal memento store within this object.
+       *  @return a functor, which on invocation will automatically store the return value
+       *        of the capturing function (= the current memento value) into the field
+       *        #memento_ within this object 
+       */
+      function<SIG>
+      tieCaptureFunc()
+        {
+          using std::tr1::placeholders::_1;
+          
+          function<void(MEM)> doCaptureMemento = bind (&MementoTie::capture, this, _1);
+          
+          return chained(capture_, doCaptureMemento);
+        }
+      
+      
+      /** get the currently captured memento state value
+       *  @throw when the capturing function wasn't yet invoked
+       */
+      MEM&
+      getState ()
+        {
+          if (!isCaptured_)
+            throw lumiera::error::State ("need to invoke memento state capturing beforehand",
+                                         LUMIERA_ERROR_MISSING_MEMENTO);
+          return memento_;
+        }
+      
+    };