content/xul/document/src/nsForwardReference.h

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   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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  14  *
  15  * The Original Code is Mozilla Communicator client code.
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  17  * The Initial Developer of the Original Code is
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  22  * Contributor(s):
  23  *   Chris Waterson <waterson@netscape.com>
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  38
  39 #ifndef nsForwardReference_h__
  40 #define nsForwardReference_h__
  41
  42 class nsForwardReference
  43 {
  44 protected:
  45     nsForwardReference() {}
  46
  47 public:
  48     virtual ~nsForwardReference() {}
  49
  50     /**
  51      * Priority codes returned from GetPhase()
  52      */
  53     enum Phase {
  54         /** A dummy marker, used to indicate unstarted resolution */
  55         eStart,
  56
  57         /** The initial pass, after which the content model will be
  58             fully built */
  59         eConstruction,
  60
  61         /** A second pass, after which all 'magic attribute' hookup
  62             will have been performed */
  63         eHookup,
  64
  65         /** A dummy marker, used in kPasses to indicate termination */
  66         eDone
  67     };
  68
  69     /**
  70      * Forward references are categorized by 'priority', and all
  71      * forward references in a higher priority are resolved before any
  72      * reference in a lower priority. This variable specifies this
  73      * ordering. The last Priority is guaranteed to be eDone.
  74      */
  75     static const Phase kPasses[];
  76
  77     /**
  78      * Get the state in which the forward reference should be resolved.
  79      * 'eConstruction' references are all resolved before 'eHookup' references
  80      * are resolved.
  81      *
  82      * @return the Phase in which the reference needs to be resolved
  83      */
  84     virtual Phase GetPhase() = 0;
  85
  86     /**
  87      * Result codes returned from Resolve()
  88      */
  89     enum Result {
  90         /** Resolution succeeded, I'm done. */
  91         eResolve_Succeeded,
  92
  93         /** Couldn't resolve, but try me later. */
  94         eResolve_Later,
  95
  96         /** Something bad happened, don't try again. */
  97         eResolve_Error
  98     };
  99
 100     /**
 101      * Attempt to resolve the forward reference.
 102      *
 103      * @return a Result that tells the resolver how to treat
 104      * the reference.
 105      */
 106     virtual Result Resolve() = 0;
 107 };
 108
 109 #endif // nsForwardReference_h__