1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/accessible/src/base/nsTextEquivUtils.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,162 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim:expandtab:shiftwidth=2:tabstop=2:
1.6 + */
1.7 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.8 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.9 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.10 +
1.11 +#ifndef _nsTextEquivUtils_H_
1.12 +#define _nsTextEquivUtils_H_
1.13 +
1.14 +#include "Accessible.h"
1.15 +#include "Role.h"
1.16 +
1.17 +class nsIContent;
1.18 +
1.19 +/**
1.20 + * Text equivalent computation rules (see nsTextEquivUtils::gRoleToNameRulesMap)
1.21 + */
1.22 +enum ETextEquivRule
1.23 +{
1.24 + // No rule.
1.25 + eNoNameRule = 0x00,
1.26 +
1.27 + // Walk into subtree only if the currently navigated accessible is not root
1.28 + // accessible (i.e. if the accessible is part of text equivalent computation).
1.29 + eNameFromSubtreeIfReqRule = 0x01,
1.30 +
1.31 + // Text equivalent computation from subtree is allowed.
1.32 + eNameFromSubtreeRule = 0x03,
1.33 +
1.34 + // The accessible allows to append its value to text equivalent.
1.35 + // XXX: This is temporary solution. Once we move accessible value of links
1.36 + // and linkable accessibles to MSAA part we can remove this.
1.37 + eNameFromValueRule = 0x04
1.38 +};
1.39 +
1.40 +/**
1.41 + * The class provides utils methods to compute the accessible name and
1.42 + * description.
1.43 + */
1.44 +class nsTextEquivUtils
1.45 +{
1.46 +public:
1.47 + typedef mozilla::a11y::Accessible Accessible;
1.48 +
1.49 + /**
1.50 + * Determines if the accessible has a given name rule.
1.51 + *
1.52 + * @param aAccessible [in] the given accessible
1.53 + * @param aRule [in] a given name rule
1.54 + * @return true if the accessible has the rule
1.55 + */
1.56 + static inline bool HasNameRule(Accessible* aAccessible, ETextEquivRule aRule)
1.57 + {
1.58 + return (GetRoleRule(aAccessible->Role()) & aRule) == aRule;
1.59 + }
1.60 +
1.61 + /**
1.62 + * Calculates the name from accessible subtree if allowed.
1.63 + *
1.64 + * @param aAccessible [in] the given accessible
1.65 + * @param aName [out] accessible name
1.66 + */
1.67 + static nsresult GetNameFromSubtree(Accessible* aAccessible,
1.68 + nsAString& aName);
1.69 +
1.70 + /**
1.71 + * Calculates text equivalent from the subtree. Similar to GetNameFromSubtree.
1.72 + * However it returns not empty result for things like HTML p.
1.73 + */
1.74 + static void GetTextEquivFromSubtree(Accessible* aAccessible,
1.75 + nsString& aTextEquiv)
1.76 + {
1.77 + aTextEquiv.Truncate();
1.78 +
1.79 + AppendFromAccessibleChildren(aAccessible, &aTextEquiv);
1.80 + aTextEquiv.CompressWhitespace();
1.81 + }
1.82 +
1.83 + /**
1.84 + * Calculates text equivalent for the given accessible from its IDRefs
1.85 + * attribute (like aria-labelledby or aria-describedby).
1.86 + *
1.87 + * @param aAccessible [in] the accessible text equivalent is computed for
1.88 + * @param aIDRefsAttr [in] IDRefs attribute on DOM node of the accessible
1.89 + * @param aTextEquiv [out] result text equivalent
1.90 + */
1.91 + static nsresult GetTextEquivFromIDRefs(Accessible* aAccessible,
1.92 + nsIAtom *aIDRefsAttr,
1.93 + nsAString& aTextEquiv);
1.94 +
1.95 + /**
1.96 + * Calculates the text equivalent from the given content and its subtree if
1.97 + * allowed and appends it to the given string.
1.98 + *
1.99 + * @param aInitiatorAcc [in] the accessible text equivalent is computed for
1.100 + * in the end (root accessible of text equivalent
1.101 + * calculation recursion)
1.102 + * @param aContent [in] the given content the text equivalent is
1.103 + * computed from
1.104 + * @param aString [in, out] the string
1.105 + */
1.106 + static nsresult AppendTextEquivFromContent(Accessible* aInitiatorAcc,
1.107 + nsIContent *aContent,
1.108 + nsAString *aString);
1.109 +
1.110 + /**
1.111 + * Calculates the text equivalent from the given text content (may be text
1.112 + * node or html:br) and appends it to the given string.
1.113 + *
1.114 + * @param aContent [in] the text content
1.115 + * @param aString [in, out] the string
1.116 + */
1.117 + static nsresult AppendTextEquivFromTextContent(nsIContent *aContent,
1.118 + nsAString *aString);
1.119 +
1.120 +private:
1.121 + /**
1.122 + * Iterates accessible children and calculates text equivalent from each
1.123 + * child.
1.124 + */
1.125 + static nsresult AppendFromAccessibleChildren(Accessible* aAccessible,
1.126 + nsAString *aString);
1.127 +
1.128 + /**
1.129 + * Calculates text equivalent from the given accessible and its subtree if
1.130 + * allowed.
1.131 + */
1.132 + static nsresult AppendFromAccessible(Accessible* aAccessible,
1.133 + nsAString *aString);
1.134 +
1.135 + /**
1.136 + * Calculates text equivalent from the value of given accessible.
1.137 + */
1.138 + static nsresult AppendFromValue(Accessible* aAccessible,
1.139 + nsAString *aString);
1.140 + /**
1.141 + * Iterates DOM children and calculates text equivalent from each child node.
1.142 + */
1.143 + static nsresult AppendFromDOMChildren(nsIContent *aContent,
1.144 + nsAString *aString);
1.145 +
1.146 + /**
1.147 + * Calculates text equivalent from the given DOM node and its subtree if
1.148 + * allowed.
1.149 + */
1.150 + static nsresult AppendFromDOMNode(nsIContent *aContent, nsAString *aString);
1.151 +
1.152 + /**
1.153 + * Concatenates strings and appends space between them. Returns true if
1.154 + * text equivalent string was appended.
1.155 + */
1.156 + static bool AppendString(nsAString *aString,
1.157 + const nsAString& aTextEquivalent);
1.158 +
1.159 + /**
1.160 + * Returns the rule (constant of ETextEquivRule) for a given role.
1.161 + */
1.162 + static uint32_t GetRoleRule(mozilla::a11y::roles::Role aRole);
1.163 +};
1.164 +
1.165 +#endif
