michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsForwardReference_h__
michael@0: #define nsForwardReference_h__
michael@0: 
michael@0: class nsForwardReference
michael@0: {
michael@0: protected:
michael@0:     nsForwardReference() {}
michael@0: 
michael@0: public:
michael@0:     virtual ~nsForwardReference() {}
michael@0: 
michael@0:     /**
michael@0:      * Priority codes returned from GetPhase()
michael@0:      */
michael@0:     enum Phase {
michael@0:         /** A dummy marker, used to indicate unstarted resolution */
michael@0:         eStart,
michael@0: 
michael@0:         /** The initial pass, after which the content model will be
michael@0:             fully built */
michael@0:         eConstruction,
michael@0: 
michael@0:         /** A second pass, after which all 'magic attribute' hookup
michael@0:             will have been performed */
michael@0:         eHookup,
michael@0: 
michael@0:         /** A dummy marker, used in kPasses to indicate termination */
michael@0:         eDone
michael@0:     };
michael@0: 
michael@0:     /**
michael@0:      * Forward references are categorized by 'priority', and all
michael@0:      * forward references in a higher priority are resolved before any
michael@0:      * reference in a lower priority. This variable specifies this
michael@0:      * ordering. The last Priority is guaranteed to be eDone.
michael@0:      */
michael@0:     static const Phase kPasses[];
michael@0: 
michael@0:     /**
michael@0:      * Get the state in which the forward reference should be resolved.
michael@0:      * 'eConstruction' references are all resolved before 'eHookup' references
michael@0:      * are resolved.
michael@0:      *
michael@0:      * @return the Phase in which the reference needs to be resolved
michael@0:      */
michael@0:     virtual Phase GetPhase() = 0;
michael@0: 
michael@0:     /**
michael@0:      * Result codes returned from Resolve()
michael@0:      */
michael@0:     enum Result {
michael@0:         /** Resolution succeeded, I'm done. */
michael@0:         eResolve_Succeeded,
michael@0: 
michael@0:         /** Couldn't resolve, but try me later. */
michael@0:         eResolve_Later,
michael@0: 
michael@0:         /** Something bad happened, don't try again. */
michael@0:         eResolve_Error
michael@0:     };
michael@0: 
michael@0:     /**
michael@0:      * Attempt to resolve the forward reference.
michael@0:      *
michael@0:      * @return a Result that tells the resolver how to treat
michael@0:      * the reference.
michael@0:      */
michael@0:     virtual Result Resolve() = 0;
michael@0: };
michael@0: 
michael@0: #endif // nsForwardReference_h__