lafagnosticuifoundation/cone/inc/Coemop.h
changeset 0 2f259fa3e83a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lafagnosticuifoundation/cone/inc/Coemop.h	Tue Feb 02 01:00:49 2010 +0200
@@ -0,0 +1,180 @@
+// Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of "Eclipse Public License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.eclipse.org/legal/epl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+//
+
+#ifndef __COEMOP_H__
+#define __COEMOP_H__
+
+#include <e32std.h>
+
+/** Declares an object type, ETypeId, for a class, in order to allow the object 
+provider mechanism to locate and provide objects from the class.
+
+@publishedAll
+@released
+@see MObjectProvider */
+#define DECLARE_TYPE_ID(id) enum { ETypeId = id };
+
+//
+// Used to wrap object type IDs in a standardised manner. Object type IDs must be asserted 
+// in an ETypeId member data property by any types of object which 
+// are capable of being retrieved by the MObjectProvider interface
+//
+class TTypeUid : public TUid
+/** Part of the object provider mechanism, this class encapsulates the Uid that 
+identifies the type of object that an object provider is to get.
+
+The class is also used to encapsulate a pointer to the object that the object 
+provider has found.
+
+An object that is intended to be capable of being retrieved by the object 
+provider mechanism must include enum {ETypeId = 0xabcdefgh}; in its class 
+definition, where 0xabcdefgh is the Uid value. The macro DECLARE_TYPE_ID can 
+be used to do this.
+
+An instance of this class is passed to the MObjectProvider::MopSupplyObject() 
+function implemented by an object provider. A TTypeUid::Ptr is also returned 
+by this function.
+
+@publishedAll
+@released
+@see MObjectProvider */
+	{
+public:
+	class Ptr
+	/** Encapsulates a pointer to an object fetched by an object provider.
+
+	The class has no public constructor. TTypeUid::MakePtr() or TTypeUid::Null() 
+	must be used to construct instances of this class. */
+		{
+		friend class TTypeUid;
+	private:
+		explicit inline Ptr(TAny* aPtr)
+			: iPtr(aPtr)
+			{}
+	public:
+		inline TAny* Pointer() const
+		/** Retrieves the pointer to an object which is encapsulated by the Ptr.
+	
+		@return A pointer to an object. */
+			{return iPtr;}
+	private:
+		TAny* iPtr;
+		};
+public:
+	inline TTypeUid(TInt aUid)
+	/** Constructor that takes a Uid value.
+	
+	@param aUid The Uid value that defines the type of object that an object provider 
+	is to get. */
+		{ iUid = aUid; }
+	inline static Ptr Null()
+	/** Constructs a Ptr which encapsulates a NULL pointer.
+	
+	@return The constructed Ptr object */
+		{ return Ptr(NULL); }
+	template <class T> inline Ptr MakePtr(T* aT) const
+	/** Constructs a Ptr which encapsulates the specified object pointer.
+	
+	@param aT A pointer to the object which is to be encapsulated.
+	@return The constructed Ptr object */
+		{ __ASSERT_DEBUG(iUid == T::ETypeId,User::Invariant()); return Ptr(aT); }
+	};
+
+
+class MObjectProvider
+/** An interface that allows an object to be part of a network of object providers.
+
+The object provider mechanism can be used to find and access objects of a 
+given type, where the type is defined by a TTypeUid object. Object providers 
+may be arranged in a hierarchy, i.e. an object provider may have a parent-child 
+relationship with another object provider.
+
+An object provider must provide an implementation for the MopSupplyObject() 
+function and can choose to provide an implementation for the MopNext() function. 
+Typically, it will also have functionality to define who its parent is.
+
+CCoeControl is an example of a class that implements this interface. Top level 
+controls must have the view or app UI set as their object provider. This is 
+done by calling CCoeControl::SetMopParent() on the view or the app UI. The 
+view or app UI does this by calling the top level control's CCoeControl::SetMopParent() 
+function. 
+
+@publishedAll 
+@released */
+	{
+public:
+	template<class T>
+	T* MopGetObject(T*& aPtr) 
+	/** Gets an object of the type defined by the template parameter.
+	
+	The object may be supplied directly by this object provider, or by other object 
+	providers higher up the hierarchy.
+	
+	@param aPtr A reference to a pointer to an object of a type that is to be 
+	retrieved.
+	@return A pointer to an object of the type required, or NULL if none can be 
+	found. */
+		{ return (aPtr=(T*)MopGetById(T::ETypeId)); }
+		
+	
+	template<class T>	
+	T*  MopGetObjectNoChaining(T*& aPtr)
+	/** Gets an object of the type defined by the template parameter.
+	
+	The object will be supplied directly by this object provider, or NULL 
+	will be returned, this function does not recurse through the object chain.
+		
+	@param aPtr A reference to a pointer to an object of a type that is to be 
+	retrieved.
+	@return A pointer to an object of the type required, or NULL if none can be 
+	found. */
+		{ return (aPtr=(T*)MopGetByIdNoChaining(T::ETypeId)); }
+	
+	/**
+	@publishedAll 
+	@released */
+	MObjectProvider* FindParent(MObjectProvider* aMopToFind);
+	
+private: // must be overridden
+	/** Gets an object whose type is encapsulated by the specified TTypeUid object.
+
+	@param aId Encapsulates the Uid that identifies the type of object required.
+	@return Encapsulates the pointer to the object provided. 
+	Note that the encapsulated pointer may be NULL.
+
+	@publishedAll 
+	@released */
+	virtual TTypeUid::Ptr MopSupplyObject(TTypeUid aId) = 0;
+
+protected:
+	IMPORT_C MObjectProvider();
+
+private: // may be overridden to continue chain of responsibility
+	/**
+	@publishedAll 
+	@released */
+	IMPORT_C virtual MObjectProvider* MopNext();
+	IMPORT_C virtual void MObjectProvider_Reserved1();
+	IMPORT_C virtual void MObjectProvider_Reserved2();
+
+private: 
+	IMPORT_C TAny* MopGetById(TTypeUid aId);
+	IMPORT_C TAny* MopGetByIdNoChaining(TTypeUid aId);
+	
+private:
+	TInt iMObjectProvider_Reserved1;
+	};
+
+#endif	// __COEMOP_H__