RP412/MUNGA/RECEIVER.h

#pragma once

#include "node.h"
#include "chain.h"
#include "memblock.h"
#include "memstrm.h"

class Receiver__SharedData;
class Receiver__InheritanceSet;
struct Receiver__HandlerEntry;
class Receiver__MessageHandlerSet;
class Receiver__Message;
class Receiver__DynamicMessage;
class Derivation;
class Event;
class DynamicMemoryStream;
class MessageTap;

//##########################################################################
//##########################    Receiver    ################################
//##########################################################################
//
// It is suggested that calls to methods meant to be serviced by a receiver
// be built through inline functions in the derived class, rather than
// having to build the parameter block in the scope of the caller.  Letting
// the inline code build the parameter block is much cleaner, and allows the
// message code numbers to be held inside the derived class, further
// protecting against calling methods for objects not in a proper derivation
// chain.
//
class Receiver:
	public Node
{
//##########################################################################
// Shared Data Support
//
public:
	typedef Receiver__SharedData SharedData;
	SharedData*
		GetSharedData() const;

	static Derivation* GetClassDerivations();
	Derivation*
		GetDerivation() const;

	static SharedData DefaultData;

	Logical
		IsDerivedFrom(Derivation& parent) const;
	Logical
		IsDerivedFrom(const char* parent) const;

protected:
	const SharedData* sharedData;

//##########################################################################
// Construction and Destruction Support
//
protected:
	Receiver(
		ClassID class_ID,
		SharedData &shared_data
	):
		Node(class_ID),
		sharedData(&shared_data)
			{}

	Receiver(
		PlugStream *stream,
		SharedData &shared_data
	):
		Node(stream),
		sharedData(&shared_data)
			{}

//##########################################################################
// Messaging Support
//
public:
	typedef Receiver__Message Message;
	typedef Receiver__DynamicMessage DynamicMessage;
	typedef Receiver__InheritanceSet InheritanceSet;
	typedef Receiver__HandlerEntry HandlerEntry;
	typedef Receiver__MessageHandlerSet MessageHandlerSet;
	typedef void (Receiver::*Handler)(const Message*);
	typedef Enumeration MessageID;

	enum {
		AnyMessageID=0,
		WatcherChangedMessageID,
		LoadResourceFinishedMessageID,
		NextMessageID
	};

	static const Handler NullHandler;

	void
		Receive(Message *What);

	virtual	void
		Dispatch(Message *What)
			{Receive(What);}

	void
		DefaultMessageHandler(Message*);

	typedef void (Receiver::*ScanCallback)(
		Receiver::Message *message,
		Receiver *receiver
	);

	MessageTap*
		MakeMessageTap(
			Derivation *derivation,
			ScanCallback callback
		);
	MessageTap*
		MakeMessageTap(
			Derivation *derivation,
			ScanCallback callback,
			Receiver::MessageID matching_message,
			Receiver *match_receiver
		);

protected:
	static const HandlerEntry MessageHandlerEntries[];
	// swapping the commented line for the following one due to inconsitincies
	// in the order of initialization for static member variables
	//static MessageHandlerSet MessageHandlers;
	static MessageHandlerSet& GetMessageHandlers();

//##########################################################################
// Event Support
//
public:
	virtual void
		Receive(Event *event);

	void
		FlushEvents(int max_priority=-1);
	void
		FlushMatchingEvents(
			MessageID target_message,
			int max_priority=-1
		);

	void
		ProcessDeferredQueue();

//##########################################################################
// Test Support
//
public:
	static Logical
		TestClass();
	Logical
		TestInstance() const;
};

//##########################################################################
//######################    Receiver::Message    ###########################
//##########################################################################

class Receiver__Message
{
public:
	#if defined(USE_SIGNATURE)
		friend int
			Is_Signature_Bad(const volatile Receiver__Message *);
	#endif

	size_t
		messageLength;
	Receiver::MessageID
		messageID;

	enum {
		ReliableBit,
		NextBit
	};

	enum {
		ReliableFlag = 1 << ReliableBit
	};

	LWord
		messageFlags;

	Receiver__Message(
		Receiver::MessageID id,
		size_t message_length
	):
		messageID(id),
		messageLength(message_length),
		messageFlags(ReliableFlag)			// HACK
			{}

	Logical
		TestInstance() const;
};

//##########################################################################
//###################    Receiver::DynamicMessage    #######################
//##########################################################################

class Receiver__DynamicMessage:
	public DynamicMemoryStream
{
public:
	Receiver__DynamicMessage()
		{}
	Receiver__DynamicMessage(
		void *stream_start,
		size_t stream_size,
		size_t initial_offset=0
	):
		DynamicMemoryStream(stream_start, stream_size, initial_offset)
			{}
	Receiver__DynamicMessage(
		Receiver::MessageID message_ID,
		size_t size = sizeof(Receiver::Message)
	);

	Receiver::Message*
		GetMessagePointer()
			{Check(this); return Cast_Object(Receiver::Message*, streamStart);}

protected:
	MemoryStream&
		WriteBytes(
			const void *ptr,
			size_t number_of_bytes
		);
};

//##########################################################################
//####################    ReceiverDataMessageOf    #########################
//##########################################################################

template <class T> class ReceiverDataMessageOf:
	public Receiver::Message
{
public:
	T
		dataContents;

	ReceiverDataMessageOf(
		Receiver::MessageID id,
		size_t message_length,
		const T& data
	):
		Receiver::Message(id, message_length),
		dataContents(data)
			{}
};

//##########################################################################
//#########################    MessageTap    ###############################
//##########################################################################

class MessageTap:
	public Plug
{
//##########################################################################
// MessageTap Functionality
//
public:
	MessageTap(
		Derivation *derivation,
		Receiver *client,
		Receiver::ScanCallback callback
	);
	MessageTap(
		Derivation *derivation,
		Receiver *client,
		Receiver::ScanCallback callback,
		Receiver::MessageID matching_message,
		Receiver *match_receiver
	);

private:
	Receiver::ScanCallback	scanCallback;
	Receiver*					clientReceiver;
	Receiver*					matchingReceiver;
	Receiver::MessageID		matchingMessageID;

public:
	void
		Scan(
			Receiver *receiver,
			Receiver::Message *message
		);

//##########################################################################
// Memory Allocation
//
private:
	static MemoryBlock* GetAllocatedMemory();

public:
	void* operator new(size_t)			{ return GetAllocatedMemory()->New(); }
	void operator delete(void *where)	{ GetAllocatedMemory()->Delete(where); }

//##########################################################################
// Test support
//
public:
	Logical
		TestInstance() const;
	static Logical
		TestClass();
};

//##########################################################################
//##################    Receiver::InheritanceSet    ########################
//##########################################################################
//
// NOTE: An InheritanceSet generated for a class should only be inherited by
//       other classes derived from that base class.  If this is not done,
//       SEVERE run-time weirdness will happen
//
class Receiver__InheritanceSet SIGNATURED
{
public:
	Logical
		TestInstance() const;
	Enumeration
		GetEntryCount()
			{Check(this); return entryCount;}

protected:
	Enumeration
		entryCount;

	Receiver__InheritanceSet()
		{}
	~Receiver__InheritanceSet()
		{}
};

//##########################################################################
//###################    Receiver::HandlerEntry    #########################
//##########################################################################

struct Receiver__HandlerEntry
{
	Enumeration
		entryID;
	const char*
		entryName;
	Receiver::Handler
		entryHandler;
};

#define MESSAGE_ENTRY(class,message)\
	{\
		class::message##MessageID,\
		#message,\
		(Receiver::Handler)&class::message##MessageHandler\
	}

//##########################################################################
//#################    Receiver::MessageHandlerSet    ######################
//##########################################################################

class Receiver__MessageHandlerSet:
	public Receiver__InheritanceSet
{
//##########################################################################
// Constructors and Destructors
//
public:
	Receiver__MessageHandlerSet(Receiver::MessageID count, const Receiver::HandlerEntry handler_table[], const Receiver::MessageHandlerSet &inheritance)	{ Build(count, handler_table, &inheritance); }
	Receiver__MessageHandlerSet(Receiver::MessageID count, const Receiver::HandlerEntry handler_table[])	{ Build(count, handler_table, NULL); }
	Receiver__MessageHandlerSet(const Receiver::MessageHandlerSet& source)		{ Build(0, NULL, &source); }
	Receiver__MessageHandlerSet()
	{
		messageHandlers = NULL;
		entryCount = 0;
	}
	~Receiver__MessageHandlerSet();

protected:
	void
		Build(
			Receiver::MessageID count,
			const Receiver::HandlerEntry handler_table[],
			const Receiver::MessageHandlerSet *inheritance
		);

//##########################################################################
// HandlerSet Functionality
//
public:
	static const Receiver::MessageHandlerSet
		NullSet;

	Receiver::Handler Find(Receiver::MessageID message) const
	{
		Check(this);
		Verify(message > 0);
		return (message<=entryCount) ? messageHandlers[message-1].entryHandler : Receiver::NullHandler;
	}

	const Receiver::HandlerEntry*
		Find(const char* name) const;

	const char *
		GetName(Receiver::MessageID message) const
			{
				Check(this);
				return (message<=entryCount)
					? messageHandlers[message-1].entryName
					: NULL;
			}

protected:
	Receiver::HandlerEntry* messageHandlers;

//##########################################################################
// Test Support
//
public:
	static Logical
		TestClass();
};

//##########################################################################
//##########################    Derivation    ##############################
//##########################################################################

class Derivation:
	public Node
{
	friend class Receiver;

//##########################################################################
// Construction and Destruction
//
public:
	Derivation(char *who);
	Derivation(Derivation *parent,char *who);

	char *className;

//##########################################################################
// Messagetap support
//
private:
	Derivation(Derivation& copy);
	ChainOf<MessageTap*>
		activeTaps;

public:
	void
		AppendMessageTap(MessageTap* tap);
	Logical
		IsDescendedFrom(Derivation& parent);
	Logical
		IsDescendedFrom(const char* parent);

//##########################################################################
// Inheritance Registration Support
//
private:
	ChainOf<Derivation*>
		classDerivations;

	void
		AppendDerivation(Derivation* child)
			{Check(this); classDerivations.Add(child);}

//##########################################################################
// Test Support
//
public:
	static Logical
		TestClass();
};

//##########################################################################
//###################    Receiver::SharedData    ##########################
//##########################################################################

class Receiver__SharedData SIGNATURED
{
public:
	Receiver__SharedData(
		Derivation* derivation,
		Receiver::MessageHandlerSet &handler
	):
		derivedClasses(derivation),
		activeMessageHandlers(&handler)
	{
		//activeMessageHandlers = &activeMessageHandlersInstance;
	}

	Derivation	*derivedClasses;
	Receiver::MessageHandlerSet	*activeMessageHandlers;

	Logical
  	TestInstance() const;
//private:
//	Receiver::MessageHandlerSet	activeMessageHandlersInstance;
};

inline Receiver::SharedData*
	Receiver::GetSharedData() const
		{Check(this); return Cast_Object(SharedData*,sharedData);}

inline Derivation*
	Receiver::GetDerivation() const
		{Check(this); return GetSharedData()->derivedClasses;}

inline Logical
	Receiver::IsDerivedFrom(Derivation& parent) const
		{return sharedData->derivedClasses->IsDescendedFrom(parent);}

inline Logical
	Receiver::IsDerivedFrom(const char* parent) const
		{Check(this); return GetDerivation()->IsDescendedFrom(parent);}

inline MessageTap*
	Receiver::MakeMessageTap(
		Derivation *derivation,
		ScanCallback callback
	)
		{Check(this); return new MessageTap(derivation, this, callback);}

inline MessageTap*
	Receiver::MakeMessageTap(
		Derivation *derivation,
		ScanCallback callback,
		Receiver::MessageID matching_message,
		Receiver *match_receiver
	)
		{
			Check(this);
			return new MessageTap(
				derivation,
				this,
				callback,
				matching_message,
				match_receiver
			);
		}