/*
 * Copyright 1995, 1996 Perforce Software.  All rights reserved.
 *
 * This file is part of Perforce - the FAST SCM System.
 */
 
/*
 * handler.h - last chance handlers to keep track of loose objects
 *
 * Handlers provide a way of associating an object with a string so
 * context can be retained across RPC dispatched function calls.  
 * This is used for file transfers, which are carried out in a series
 * of RPC calls.  The sender picks a handle name and then uses that
 * consistenly during the transfer.  The receiver uses the provided handle
 * name to stash and retrieve the object the represents the open file.
 *
 * Handlers also provide a means of tracking across objects.  If any
 * object encounters an error, it can mark the handle so that a subsequent
 * call to AnyErrors() can report so.
 *
 * Public classes:
 *
 *	Handlers - a list of LastChance objects
 *	LastChance - a virtual base class that gets deleted with the
 *			handlers.
 */
 
class LastChance;
 
struct Handler {
	    StrBuf	name;
	    int		anyErrors;
	    LastChance	*lastChance;
} ;
 
class LastChance {
 
    public:
			LastChance()
			{
			    handler = 0;
			    isError = 0;
			}
 
	virtual		~LastChance();
 
	void		Install( Handler *h )
			{
			    handler = h; 
			    handler->lastChance = this;
			}
 
	void		SetError()
			{
			    isError = 1;
			}
 
	void		SetError( Error *e )
			{
			    if( e->Test() ) isError = 1;
			}
 
	int		IsError()
			{
			    return isError;
			}
 
    private:
	Handler		*handler;
	int		isError;
 
} ;
 
const int maxHandlers = 3;
 
class Handlers {
 
    public:
			Handlers();
			~Handlers();
 
	void		Install( const StrPtr *name, 
				LastChance *lastChance,
				Error *e );
 
	LastChance *	Get( const StrPtr *name, Error *e );
 
	int		AnyErrors( const StrPtr *nane );
 
    private:
 
	int		numHandlers;
	Handler 	table[maxHandlers];
	Handler		*Find( const StrPtr *handle, Error *e = 0 );
} ;