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-rw-r--r--accessible/base/nsTextEquivUtils.cpp367
1 files changed, 367 insertions, 0 deletions
diff --git a/accessible/base/nsTextEquivUtils.cpp b/accessible/base/nsTextEquivUtils.cpp
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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/. */
+
+#include "nsTextEquivUtils.h"
+
+#include "LocalAccessible.h"
+#include "LocalAccessible-inl.h"
+#include "AccIterator.h"
+#include "nsCoreUtils.h"
+#include "mozilla/dom/Text.h"
+#include "nsIContentInlines.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+/**
+ * The accessible for which we are computing a text equivalent. It is useful
+ * for bailing out during recursive text computation, or for special cases
+ * like step f. of the ARIA implementation guide.
+ */
+static const Accessible* sInitiatorAcc = nullptr;
+
+////////////////////////////////////////////////////////////////////////////////
+// nsTextEquivUtils. Public.
+
+nsresult nsTextEquivUtils::GetNameFromSubtree(
+ const LocalAccessible* aAccessible, nsAString& aName) {
+ aName.Truncate();
+
+ if (sInitiatorAcc) return NS_OK;
+
+ sInitiatorAcc = aAccessible;
+ if (GetRoleRule(aAccessible->Role()) == eNameFromSubtreeRule) {
+ // XXX: is it necessary to care the accessible is not a document?
+ if (aAccessible->IsContent()) {
+ nsAutoString name;
+ AppendFromAccessibleChildren(aAccessible, &name);
+ name.CompressWhitespace();
+ if (!nsCoreUtils::IsWhitespaceString(name)) aName = name;
+ }
+ }
+
+ sInitiatorAcc = nullptr;
+
+ return NS_OK;
+}
+
+nsresult nsTextEquivUtils::GetTextEquivFromIDRefs(
+ const LocalAccessible* aAccessible, nsAtom* aIDRefsAttr,
+ nsAString& aTextEquiv) {
+ aTextEquiv.Truncate();
+
+ nsIContent* content = aAccessible->GetContent();
+ if (!content) return NS_OK;
+
+ nsIContent* refContent = nullptr;
+ IDRefsIterator iter(aAccessible->Document(), content, aIDRefsAttr);
+ while ((refContent = iter.NextElem())) {
+ if (!aTextEquiv.IsEmpty()) aTextEquiv += ' ';
+
+ nsresult rv =
+ AppendTextEquivFromContent(aAccessible, refContent, &aTextEquiv);
+ NS_ENSURE_SUCCESS(rv, rv);
+ }
+
+ return NS_OK;
+}
+
+nsresult nsTextEquivUtils::AppendTextEquivFromContent(
+ const LocalAccessible* aInitiatorAcc, nsIContent* aContent,
+ nsAString* aString) {
+ // Prevent recursion which can cause infinite loops.
+ if (sInitiatorAcc) return NS_OK;
+
+ sInitiatorAcc = aInitiatorAcc;
+
+ // If the given content is not visible or isn't accessible then go down
+ // through the DOM subtree otherwise go down through accessible subtree and
+ // calculate the flat string.
+ nsIFrame* frame = aContent->GetPrimaryFrame();
+ bool isVisible = frame && frame->StyleVisibility()->IsVisible();
+
+ nsresult rv = NS_ERROR_FAILURE;
+ bool goThroughDOMSubtree = true;
+
+ if (isVisible) {
+ LocalAccessible* accessible =
+ aInitiatorAcc->Document()->GetAccessible(aContent);
+ if (accessible) {
+ rv = AppendFromAccessible(accessible, aString);
+ goThroughDOMSubtree = false;
+ }
+ }
+
+ if (goThroughDOMSubtree) rv = AppendFromDOMNode(aContent, aString);
+
+ sInitiatorAcc = nullptr;
+ return rv;
+}
+
+nsresult nsTextEquivUtils::AppendTextEquivFromTextContent(nsIContent* aContent,
+ nsAString* aString) {
+ if (aContent->IsText()) {
+ if (aContent->TextLength() > 0) {
+ nsIFrame* frame = aContent->GetPrimaryFrame();
+ if (frame) {
+ nsIFrame::RenderedText text = frame->GetRenderedText(
+ 0, UINT32_MAX, nsIFrame::TextOffsetType::OffsetsInContentText,
+ nsIFrame::TrailingWhitespace::DontTrim);
+ aString->Append(text.mString);
+ } else {
+ // If aContent is an object that is display: none, we have no a frame.
+ aContent->GetAsText()->AppendTextTo(*aString);
+ }
+ }
+
+ return NS_OK;
+ }
+
+ if (aContent->IsHTMLElement() &&
+ aContent->NodeInfo()->Equals(nsGkAtoms::br)) {
+ aString->AppendLiteral("\r\n");
+ return NS_OK;
+ }
+
+ return NS_OK_NO_NAME_CLAUSE_HANDLED;
+}
+
+nsresult nsTextEquivUtils::AppendFromDOMChildren(nsIContent* aContent,
+ nsAString* aString) {
+ for (nsIContent* childContent = aContent->GetFirstChild(); childContent;
+ childContent = childContent->GetNextSibling()) {
+ nsresult rv = AppendFromDOMNode(childContent, aString);
+ NS_ENSURE_SUCCESS(rv, rv);
+ }
+
+ return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsTextEquivUtils. Private.
+
+nsresult nsTextEquivUtils::AppendFromAccessibleChildren(
+ const Accessible* aAccessible, nsAString* aString) {
+ nsresult rv = NS_OK_NO_NAME_CLAUSE_HANDLED;
+
+ uint32_t childCount = aAccessible->ChildCount();
+ for (uint32_t childIdx = 0; childIdx < childCount; childIdx++) {
+ Accessible* child = aAccessible->ChildAt(childIdx);
+ rv = AppendFromAccessible(child, aString);
+ NS_ENSURE_SUCCESS(rv, rv);
+ }
+
+ return rv;
+}
+
+nsresult nsTextEquivUtils::AppendFromAccessible(Accessible* aAccessible,
+ nsAString* aString) {
+ // XXX: is it necessary to care the accessible is not a document?
+ bool isHTMLBlock = false;
+ if (aAccessible->IsLocal() && aAccessible->AsLocal()->IsContent()) {
+ nsIContent* content = aAccessible->AsLocal()->GetContent();
+ nsresult rv = AppendTextEquivFromTextContent(content, aString);
+ if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) return rv;
+ if (!content->IsText()) {
+ nsIFrame* frame = content->GetPrimaryFrame();
+ if (frame) {
+ // If this is a block level frame (as opposed to span level), we need to
+ // add spaces around that block's text, so we don't get words jammed
+ // together in final name.
+ const nsStyleDisplay* display = frame->StyleDisplay();
+ if (display->IsBlockOutsideStyle() ||
+ display->mDisplay == StyleDisplay::TableCell) {
+ isHTMLBlock = true;
+ if (!aString->IsEmpty()) {
+ aString->Append(char16_t(' '));
+ }
+ }
+ }
+ }
+ }
+
+ bool isEmptyTextEquiv = true;
+
+ // If the name is from tooltip then append it to result string in the end
+ // (see h. step of name computation guide).
+ nsAutoString text;
+ if (aAccessible->Name(text) != eNameFromTooltip) {
+ isEmptyTextEquiv = !AppendString(aString, text);
+ }
+
+ // Implementation of f. step.
+ nsresult rv = AppendFromValue(aAccessible, aString);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) isEmptyTextEquiv = false;
+
+ // Implementation of g) step of text equivalent computation guide. Go down
+ // into subtree if accessible allows "text equivalent from subtree rule" or
+ // it's not root and not control.
+ if (isEmptyTextEquiv) {
+ if (ShouldIncludeInSubtreeCalculation(aAccessible)) {
+ rv = AppendFromAccessibleChildren(aAccessible, aString);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) isEmptyTextEquiv = false;
+ }
+ }
+
+ // Implementation of h. step
+ if (isEmptyTextEquiv && !text.IsEmpty()) {
+ AppendString(aString, text);
+ if (isHTMLBlock) {
+ aString->Append(char16_t(' '));
+ }
+ return NS_OK;
+ }
+
+ if (!isEmptyTextEquiv && isHTMLBlock) {
+ aString->Append(char16_t(' '));
+ }
+ return rv;
+}
+
+nsresult nsTextEquivUtils::AppendFromValue(Accessible* aAccessible,
+ nsAString* aString) {
+ if (GetRoleRule(aAccessible->Role()) != eNameFromValueRule) {
+ return NS_OK_NO_NAME_CLAUSE_HANDLED;
+ }
+
+ // Implementation of step f. of text equivalent computation. If the given
+ // accessible is not root accessible (the accessible the text equivalent is
+ // computed for in the end) then append accessible value. Otherwise append
+ // value if and only if the given accessible is in the middle of its parent.
+
+ nsAutoString text;
+ if (aAccessible != sInitiatorAcc) {
+ aAccessible->Value(text);
+
+ return AppendString(aString, text) ? NS_OK : NS_OK_NO_NAME_CLAUSE_HANDLED;
+ }
+
+ // XXX: is it necessary to care the accessible is not a document?
+ if (aAccessible->IsDoc()) return NS_ERROR_UNEXPECTED;
+
+ for (Accessible* next = aAccessible->NextSibling(); next;
+ next = next->NextSibling()) {
+ if (!IsWhitespaceLeaf(next)) {
+ for (Accessible* prev = aAccessible->PrevSibling(); prev;
+ prev = prev->PrevSibling()) {
+ if (!IsWhitespaceLeaf(prev)) {
+ aAccessible->Value(text);
+
+ return AppendString(aString, text) ? NS_OK
+ : NS_OK_NO_NAME_CLAUSE_HANDLED;
+ }
+ }
+ }
+ }
+
+ return NS_OK_NO_NAME_CLAUSE_HANDLED;
+}
+
+nsresult nsTextEquivUtils::AppendFromDOMNode(nsIContent* aContent,
+ nsAString* aString) {
+ nsresult rv = AppendTextEquivFromTextContent(aContent, aString);
+ NS_ENSURE_SUCCESS(rv, rv);
+
+ if (rv != NS_OK_NO_NAME_CLAUSE_HANDLED) return NS_OK;
+
+ if (aContent->IsXULElement()) {
+ nsAutoString textEquivalent;
+ if (aContent->NodeInfo()->Equals(nsGkAtoms::label, kNameSpaceID_XUL)) {
+ aContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::value,
+ textEquivalent);
+ } else {
+ aContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::label,
+ textEquivalent);
+ }
+
+ if (textEquivalent.IsEmpty()) {
+ aContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::tooltiptext,
+ textEquivalent);
+ }
+
+ AppendString(aString, textEquivalent);
+ }
+
+ return AppendFromDOMChildren(aContent, aString);
+}
+
+bool nsTextEquivUtils::AppendString(nsAString* aString,
+ const nsAString& aTextEquivalent) {
+ if (aTextEquivalent.IsEmpty()) return false;
+
+ // Insert spaces to insure that words from controls aren't jammed together.
+ if (!aString->IsEmpty() && !nsCoreUtils::IsWhitespace(aString->Last())) {
+ aString->Append(char16_t(' '));
+ }
+
+ aString->Append(aTextEquivalent);
+
+ if (!nsCoreUtils::IsWhitespace(aString->Last())) {
+ aString->Append(char16_t(' '));
+ }
+
+ return true;
+}
+
+uint32_t nsTextEquivUtils::GetRoleRule(role aRole) {
+#define ROLE(geckoRole, stringRole, ariaRole, atkRole, macRole, macSubrole, \
+ msaaRole, ia2Role, androidClass, nameRule) \
+ case roles::geckoRole: \
+ return nameRule;
+
+ switch (aRole) {
+#include "RoleMap.h"
+ default:
+ MOZ_CRASH("Unknown role.");
+ }
+
+#undef ROLE
+}
+
+bool nsTextEquivUtils::ShouldIncludeInSubtreeCalculation(
+ Accessible* aAccessible) {
+ uint32_t nameRule = GetRoleRule(aAccessible->Role());
+ if (nameRule == eNameFromSubtreeRule) {
+ return true;
+ }
+ if (!(nameRule & eNameFromSubtreeIfReqRule)) {
+ return false;
+ }
+
+ if (aAccessible == sInitiatorAcc) {
+ // We're calculating the text equivalent for this accessible, but this
+ // accessible should only be included when calculating the text equivalent
+ // for something else.
+ return false;
+ }
+
+ // sInitiatorAcc can be null when, for example, LocalAccessible::Value calls
+ // GetTextEquivFromSubtree.
+ role initiatorRole = sInitiatorAcc ? sInitiatorAcc->Role() : roles::NOTHING;
+ if (initiatorRole == roles::OUTLINEITEM &&
+ aAccessible->Role() == roles::GROUPING) {
+ // Child treeitems are contained in a group. We don't want to include those
+ // in the parent treeitem's text equivalent.
+ return false;
+ }
+
+ return true;
+}
+
+bool nsTextEquivUtils::IsWhitespaceLeaf(Accessible* aAccessible) {
+ if (!aAccessible || !aAccessible->IsTextLeaf()) {
+ return false;
+ }
+
+ nsAutoString name;
+ aAccessible->Name(name);
+ return nsCoreUtils::IsWhitespaceString(name);
+}