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       1             : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
       2             : /* This Source Code Form is subject to the terms of the Mozilla Public
       3             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       4             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       5             : 
       6             : #ifndef nsForwardReference_h__
       7             : #define nsForwardReference_h__
       8             : 
       9             : class nsForwardReference
      10             : {
      11             : protected:
      12          47 :     nsForwardReference() {}
      13             : 
      14             : public:
      15          47 :     virtual ~nsForwardReference() {}
      16             : 
      17             :     /**
      18             :      * Priority codes returned from GetPhase()
      19             :      */
      20             :     enum Phase {
      21             :         /** A dummy marker, used to indicate unstarted resolution */
      22             :         eStart,
      23             : 
      24             :         /** The initial pass, after which the content model will be
      25             :             fully built */
      26             :         eConstruction,
      27             : 
      28             :         /** A second pass, after which all 'magic attribute' hookup
      29             :             will have been performed */
      30             :         eHookup,
      31             : 
      32             :         /** A dummy marker, used in kPasses to indicate termination */
      33             :         eDone
      34             :     };
      35             : 
      36             :     /**
      37             :      * Forward references are categorized by 'priority', and all
      38             :      * forward references in a higher priority are resolved before any
      39             :      * reference in a lower priority. This variable specifies this
      40             :      * ordering. The last Priority is guaranteed to be eDone.
      41             :      */
      42             :     static const Phase kPasses[];
      43             : 
      44             :     /**
      45             :      * Get the state in which the forward reference should be resolved.
      46             :      * 'eConstruction' references are all resolved before 'eHookup' references
      47             :      * are resolved.
      48             :      *
      49             :      * @return the Phase in which the reference needs to be resolved
      50             :      */
      51             :     virtual Phase GetPhase() = 0;
      52             : 
      53             :     /**
      54             :      * Result codes returned from Resolve()
      55             :      */
      56             :     enum Result {
      57             :         /** Resolution succeeded, I'm done. */
      58             :         eResolve_Succeeded,
      59             : 
      60             :         /** Couldn't resolve, but try me later. */
      61             :         eResolve_Later,
      62             : 
      63             :         /** Something bad happened, don't try again. */
      64             :         eResolve_Error
      65             :     };
      66             : 
      67             :     /**
      68             :      * Attempt to resolve the forward reference.
      69             :      *
      70             :      * @return a Result that tells the resolver how to treat
      71             :      * the reference.
      72             :      */
      73             :     virtual Result Resolve() = 0;
      74             : };
      75             : 
      76             : #endif // nsForwardReference_h__