1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /* ***** BEGIN LICENSE BLOCK *****
3 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 : *
5 : * The contents of this file are subject to the Mozilla Public License Version
6 : * 1.1 (the "License"); you may not use this file except in compliance with
7 : * the License. You may obtain a copy of the License at
8 : * http://www.mozilla.org/MPL/
9 : *
10 : * Software distributed under the License is distributed on an "AS IS" basis,
11 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 : * for the specific language governing rights and limitations under the
13 : * License.
14 : *
15 : * The Original Code is Mozilla Communicator client code.
16 : *
17 : * The Initial Developer of the Original Code is
18 : * Netscape Communications Corporation.
19 : * Portions created by the Initial Developer are Copyright (C) 1998
20 : * the Initial Developer. All Rights Reserved.
21 : *
22 : * Contributor(s):
23 : * Chris Waterson <waterson@netscape.com>
24 : *
25 : * Alternatively, the contents of this file may be used under the terms of
26 : * either of the GNU General Public License Version 2 or later (the "GPL"),
27 : * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 : * in which case the provisions of the GPL or the LGPL are applicable instead
29 : * of those above. If you wish to allow use of your version of this file only
30 : * under the terms of either the GPL or the LGPL, and not to allow others to
31 : * use your version of this file under the terms of the MPL, indicate your
32 : * decision by deleting the provisions above and replace them with the notice
33 : * and other provisions required by the GPL or the LGPL. If you do not delete
34 : * the provisions above, a recipient may use your version of this file under
35 : * the terms of any one of the MPL, the GPL or the LGPL.
36 : *
37 : * ***** END LICENSE BLOCK ***** */
38 :
39 : #ifndef nsForwardReference_h__
40 : #define nsForwardReference_h__
41 :
42 : class nsForwardReference
43 : {
44 : protected:
45 0 : nsForwardReference() {}
46 :
47 : public:
48 0 : 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__
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