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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _nsTextEquivUtils_H_
+#define _nsTextEquivUtils_H_
+
+#include "Accessible.h"
+#include "Role.h"
+
+class nsIContent;
+
+/**
+ * Text equivalent computation rules (see nsTextEquivUtils::gRoleToNameRulesMap)
+ */
+enum ETextEquivRule
+{
+ // No rule.
+ eNoNameRule = 0x00,
+
+ // Walk into subtree only if the currently navigated accessible is not root
+ // accessible (i.e. if the accessible is part of text equivalent computation).
+ eNameFromSubtreeIfReqRule = 0x01,
+
+ // Text equivalent computation from subtree is allowed.
+ eNameFromSubtreeRule = 0x03,
+
+ // The accessible allows to append its value to text equivalent.
+ // XXX: This is temporary solution. Once we move accessible value of links
+ // and linkable accessibles to MSAA part we can remove this.
+ eNameFromValueRule = 0x04
+};
+
+/**
+ * The class provides utils methods to compute the accessible name and
+ * description.
+ */
+class nsTextEquivUtils
+{
+public:
+ typedef mozilla::a11y::Accessible Accessible;
+
+ /**
+ * Determines if the accessible has a given name rule.
+ *
+ * @param aAccessible [in] the given accessible
+ * @param aRule [in] a given name rule
+ * @return true if the accessible has the rule
+ */
+ static inline bool HasNameRule(Accessible* aAccessible, ETextEquivRule aRule)
+ {
+ return (GetRoleRule(aAccessible->Role()) & aRule) == aRule;
+ }
+
+ /**
+ * Calculates the name from accessible subtree if allowed.
+ *
+ * @param aAccessible [in] the given accessible
+ * @param aName [out] accessible name
+ */
+ static nsresult GetNameFromSubtree(Accessible* aAccessible,
+ nsAString& aName);
+
+ /**
+ * Calculates text equivalent from the subtree. Similar to GetNameFromSubtree.
+ * However it returns not empty result for things like HTML p.
+ */
+ static void GetTextEquivFromSubtree(Accessible* aAccessible,
+ nsString& aTextEquiv)
+ {
+ aTextEquiv.Truncate();
+
+ AppendFromAccessibleChildren(aAccessible, &aTextEquiv);
+ aTextEquiv.CompressWhitespace();
+ }
+
+ /**
+ * Calculates text equivalent for the given accessible from its IDRefs
+ * attribute (like aria-labelledby or aria-describedby).
+ *
+ * @param aAccessible [in] the accessible text equivalent is computed for
+ * @param aIDRefsAttr [in] IDRefs attribute on DOM node of the accessible
+ * @param aTextEquiv [out] result text equivalent
+ */
+ static nsresult GetTextEquivFromIDRefs(Accessible* aAccessible,
+ nsIAtom *aIDRefsAttr,
+ nsAString& aTextEquiv);
+
+ /**
+ * Calculates the text equivalent from the given content and its subtree if
+ * allowed and appends it to the given string.
+ *
+ * @param aInitiatorAcc [in] the accessible text equivalent is computed for
+ * in the end (root accessible of text equivalent
+ * calculation recursion)
+ * @param aContent [in] the given content the text equivalent is
+ * computed from
+ * @param aString [in, out] the string
+ */
+ static nsresult AppendTextEquivFromContent(Accessible* aInitiatorAcc,
+ nsIContent *aContent,
+ nsAString *aString);
+
+ /**
+ * Calculates the text equivalent from the given text content (may be text
+ * node or html:br) and appends it to the given string.
+ *
+ * @param aContent [in] the text content
+ * @param aString [in, out] the string
+ */
+ static nsresult AppendTextEquivFromTextContent(nsIContent *aContent,
+ nsAString *aString);
+
+private:
+ /**
+ * Iterates accessible children and calculates text equivalent from each
+ * child.
+ */
+ static nsresult AppendFromAccessibleChildren(Accessible* aAccessible,
+ nsAString *aString);
+
+ /**
+ * Calculates text equivalent from the given accessible and its subtree if
+ * allowed.
+ */
+ static nsresult AppendFromAccessible(Accessible* aAccessible,
+ nsAString *aString);
+
+ /**
+ * Calculates text equivalent from the value of given accessible.
+ */
+ static nsresult AppendFromValue(Accessible* aAccessible,
+ nsAString *aString);
+ /**
+ * Iterates DOM children and calculates text equivalent from each child node.
+ */
+ static nsresult AppendFromDOMChildren(nsIContent *aContent,
+ nsAString *aString);
+
+ /**
+ * Calculates text equivalent from the given DOM node and its subtree if
+ * allowed.
+ */
+ static nsresult AppendFromDOMNode(nsIContent *aContent, nsAString *aString);
+
+ /**
+ * Concatenates strings and appends space between them. Returns true if
+ * text equivalent string was appended.
+ */
+ static bool AppendString(nsAString *aString,
+ const nsAString& aTextEquivalent);
+
+ /**
+ * Returns the rule (constant of ETextEquivRule) for a given role.
+ */
+ static uint32_t GetRoleRule(mozilla::a11y::roles::Role aRole);
+};
+
+#endif