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Diffstat (limited to 'accessible/base/nsTextEquivUtils.cpp')
| -rw-r--r-- | accessible/base/nsTextEquivUtils.cpp | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/accessible/base/nsTextEquivUtils.cpp b/accessible/base/nsTextEquivUtils.cpp new file mode 100644 index 0000000000..d95229c1dc --- /dev/null +++ b/accessible/base/nsTextEquivUtils.cpp @@ -0,0 +1,360 @@ +/* -*- 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-inl.h" +#include "AccIterator.h" +#include "nsCoreUtils.h" +#include "mozilla/dom/ChildIterator.h" +#include "mozilla/dom/Text.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 += ' '; + + if (refContent->IsHTMLElement(nsGkAtoms::slot)) printf("jtd idref slot\n"); + 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; + + nsresult rv = NS_ERROR_FAILURE; + if (LocalAccessible* accessible = + aInitiatorAcc->Document()->GetAccessible(aContent)) { + rv = AppendFromAccessible(accessible, aString); + } else { + // The given content is invisible or otherwise inaccessible, so use the DOM + // subtree. + 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) { + auto iter = + dom::AllChildrenIterator(aContent, nsIContent::eAllChildren, true); + while (nsIContent* childContent = iter.GetNextChild()) { + 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->IsAnyOfHTMLElements(nsGkAtoms::script, nsGkAtoms::style)) { + // The text within these elements is never meant for users. + return NS_OK; + } + + if (aContent->IsXULElement()) { + nsAutoString textEquivalent; + if (aContent->NodeInfo()->Equals(nsGkAtoms::label, kNameSpaceID_XUL)) { + aContent->AsElement()->GetAttr(nsGkAtoms::value, textEquivalent); + } else { + aContent->AsElement()->GetAttr(nsGkAtoms::label, textEquivalent); + } + + if (textEquivalent.IsEmpty()) { + aContent->AsElement()->GetAttr(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); +} |