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1 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 : /* vim:expandtab:shiftwidth=2:tabstop=2:
3 : */
4 : /* This Source Code Form is subject to the terms of the Mozilla Public
5 : * License, v. 2.0. If a copy of the MPL was not distributed with this
6 : * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
7 :
8 : #ifndef _nsTextEquivUtils_H_
9 : #define _nsTextEquivUtils_H_
10 :
11 : #include "Accessible.h"
12 : #include "Role.h"
13 :
14 : class nsIContent;
15 :
16 : /**
17 : * Text equivalent computation rules (see nsTextEquivUtils::gRoleToNameRulesMap)
18 : */
19 : enum ETextEquivRule
20 : {
21 : // No rule.
22 : eNoNameRule = 0x00,
23 :
24 : // Walk into subtree only if the currently navigated accessible is not root
25 : // accessible (i.e. if the accessible is part of text equivalent computation).
26 : eNameFromSubtreeIfReqRule = 0x01,
27 :
28 : // Text equivalent computation from subtree is allowed.
29 : eNameFromSubtreeRule = 0x03,
30 :
31 : // The accessible allows to append its value to text equivalent.
32 : // XXX: This is temporary solution. Once we move accessible value of links
33 : // and linkable accessibles to MSAA part we can remove this.
34 : eNameFromValueRule = 0x04
35 : };
36 :
37 : /**
38 : * The class provides utils methods to compute the accessible name and
39 : * description.
40 : */
41 : class nsTextEquivUtils
42 : {
43 : public:
44 : typedef mozilla::a11y::Accessible Accessible;
45 :
46 : /**
47 : * Determines if the accessible has a given name rule.
48 : *
49 : * @param aAccessible [in] the given accessible
50 : * @param aRule [in] a given name rule
51 : * @return true if the accessible has the rule
52 : */
53 0 : static inline bool HasNameRule(Accessible* aAccessible, ETextEquivRule aRule)
54 : {
55 0 : return (GetRoleRule(aAccessible->Role()) & aRule) == aRule;
56 : }
57 :
58 : /**
59 : * Calculates the name from accessible subtree if allowed.
60 : *
61 : * @param aAccessible [in] the given accessible
62 : * @param aName [out] accessible name
63 : */
64 : static nsresult GetNameFromSubtree(Accessible* aAccessible,
65 : nsAString& aName);
66 :
67 : /**
68 : * Calculates text equivalent from the subtree. Similar to GetNameFromSubtree.
69 : * However it returns not empty result for things like HTML p.
70 : */
71 0 : static void GetTextEquivFromSubtree(Accessible* aAccessible,
72 : nsString& aTextEquiv)
73 : {
74 0 : aTextEquiv.Truncate();
75 :
76 0 : AppendFromAccessibleChildren(aAccessible, &aTextEquiv);
77 0 : aTextEquiv.CompressWhitespace();
78 0 : }
79 :
80 : /**
81 : * Calculates text equivalent for the given accessible from its IDRefs
82 : * attribute (like aria-labelledby or aria-describedby).
83 : *
84 : * @param aAccessible [in] the accessible text equivalent is computed for
85 : * @param aIDRefsAttr [in] IDRefs attribute on DOM node of the accessible
86 : * @param aTextEquiv [out] result text equivalent
87 : */
88 : static nsresult GetTextEquivFromIDRefs(Accessible* aAccessible,
89 : nsIAtom *aIDRefsAttr,
90 : nsAString& aTextEquiv);
91 :
92 : /**
93 : * Calculates the text equivalent from the given content and its subtree if
94 : * allowed and appends it to the given string.
95 : *
96 : * @param aInitiatorAcc [in] the accessible text equivalent is computed for
97 : * in the end (root accessible of text equivalent
98 : * calculation recursion)
99 : * @param aContent [in] the given content the text equivalent is
100 : * computed from
101 : * @param aString [in, out] the string
102 : */
103 : static nsresult AppendTextEquivFromContent(Accessible* aInitiatorAcc,
104 : nsIContent *aContent,
105 : nsAString *aString);
106 :
107 : /**
108 : * Calculates the text equivalent from the given text content (may be text
109 : * node or html:br) and appends it to the given string.
110 : *
111 : * @param aContent [in] the text content
112 : * @param aString [in, out] the string
113 : */
114 : static nsresult AppendTextEquivFromTextContent(nsIContent *aContent,
115 : nsAString *aString);
116 :
117 : private:
118 : /**
119 : * Iterates accessible children and calculates text equivalent from each
120 : * child.
121 : */
122 : static nsresult AppendFromAccessibleChildren(Accessible* aAccessible,
123 : nsAString *aString);
124 :
125 : /**
126 : * Calculates text equivalent from the given accessible and its subtree if
127 : * allowed.
128 : */
129 : static nsresult AppendFromAccessible(Accessible* aAccessible,
130 : nsAString *aString);
131 :
132 : /**
133 : * Calculates text equivalent from the value of given accessible.
134 : */
135 : static nsresult AppendFromValue(Accessible* aAccessible,
136 : nsAString *aString);
137 : /**
138 : * Iterates DOM children and calculates text equivalent from each child node.
139 : */
140 : static nsresult AppendFromDOMChildren(nsIContent *aContent,
141 : nsAString *aString);
142 :
143 : /**
144 : * Calculates text equivalent from the given DOM node and its subtree if
145 : * allowed.
146 : */
147 : static nsresult AppendFromDOMNode(nsIContent *aContent, nsAString *aString);
148 :
149 : /**
150 : * Concatenates strings and appends space between them. Returns true if
151 : * text equivalent string was appended.
152 : */
153 : static bool AppendString(nsAString *aString,
154 : const nsAString& aTextEquivalent);
155 :
156 : /**
157 : * Returns the rule (constant of ETextEquivRule) for a given role.
158 : */
159 : static uint32_t GetRoleRule(mozilla::a11y::roles::Role aRole);
160 : };
161 :
162 : #endif
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