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-rw-r--r--layout/mathml/nsMathMLsemanticsFrame.cpp117
1 files changed, 117 insertions, 0 deletions
diff --git a/layout/mathml/nsMathMLsemanticsFrame.cpp b/layout/mathml/nsMathMLsemanticsFrame.cpp
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+++ b/layout/mathml/nsMathMLsemanticsFrame.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "nsMathMLsemanticsFrame.h"
+
+#include "nsMimeTypes.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/gfx/2D.h"
+
+using namespace mozilla;
+
+//
+// <semantics> -- associate annotations with a MathML expression
+//
+
+nsIFrame* NS_NewMathMLsemanticsFrame(PresShell* aPresShell,
+ ComputedStyle* aStyle) {
+ return new (aPresShell)
+ nsMathMLsemanticsFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsMathMLsemanticsFrame)
+
+nsMathMLsemanticsFrame::~nsMathMLsemanticsFrame() = default;
+
+nsIFrame* nsMathMLsemanticsFrame::GetSelectedFrame() {
+ // By default, we will display the first child of the <semantics> element.
+ nsIFrame* childFrame = mFrames.FirstChild();
+ mSelectedFrame = childFrame;
+
+ // An empty <semantics> is invalid
+ if (!childFrame) {
+ mInvalidMarkup = true;
+ return mSelectedFrame;
+ }
+ mInvalidMarkup = false;
+
+ // Using <annotation> or <annotation-xml> as a first child is invalid.
+ // However some people use this syntax so we take care of this case too.
+ bool firstChildIsAnnotation = false;
+ nsIContent* childContent = childFrame->GetContent();
+ if (childContent->IsAnyOfMathMLElements(nsGkAtoms::annotation_,
+ nsGkAtoms::annotation_xml_)) {
+ firstChildIsAnnotation = true;
+ }
+
+ // If the first child is a presentation MathML element other than
+ // <annotation> or <annotation-xml>, we are done.
+ if (!firstChildIsAnnotation && childFrame->IsFrameOfType(nsIFrame::eMathML)) {
+ nsIMathMLFrame* mathMLFrame = do_QueryFrame(childFrame);
+ if (mathMLFrame) {
+ TransmitAutomaticData();
+ return mSelectedFrame;
+ }
+ // The first child is not an annotation, so skip it.
+ childFrame = childFrame->GetNextSibling();
+ }
+
+ // Otherwise, we read the list of annotations and select the first one that
+ // could be displayed in place of the first child of <semantics>. If none is
+ // found, we fallback to this first child.
+ for (; childFrame; childFrame = childFrame->GetNextSibling()) {
+ nsIContent* childContent = childFrame->GetContent();
+
+ if (childContent->IsMathMLElement(nsGkAtoms::annotation_)) {
+ // If the <annotation> element has an src attribute we ignore it.
+ // XXXfredw Should annotation images be supported? See the related
+ // bug 297465 for mglyph.
+ if (childContent->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::src))
+ continue;
+
+ // Otherwise, we assume it is a text annotation that can always be
+ // displayed and stop here.
+ mSelectedFrame = childFrame;
+ break;
+ }
+
+ if (childContent->IsMathMLElement(nsGkAtoms::annotation_xml_)) {
+ // If the <annotation-xml> element has an src attribute we ignore it.
+ if (childContent->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::src))
+ continue;
+
+ // If the <annotation-xml> element has an encoding attribute
+ // describing presentation MathML, SVG or HTML we assume the content
+ // can be displayed and stop here.
+ //
+ // We recognize the following encoding values:
+ //
+ // - "MathML-Presentation", which is mentioned in the MathML3 REC
+ // - "SVG1.1" which is mentioned in the W3C note
+ // http://www.w3.org/Math/Documents/Notes/graphics.xml
+ // - Other mime Content-Types for SVG and HTML
+ //
+ // We exclude APPLICATION_MATHML_XML = "application/mathml+xml" which
+ // is ambiguous about whether it is Presentation or Content MathML.
+ // Authors must use a more explicit encoding value.
+ nsAutoString value;
+ childContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::encoding,
+ value);
+ if (value.EqualsLiteral("application/mathml-presentation+xml") ||
+ value.EqualsLiteral("MathML-Presentation") ||
+ value.EqualsLiteral(IMAGE_SVG_XML) || value.EqualsLiteral("SVG1.1") ||
+ value.EqualsLiteral(APPLICATION_XHTML_XML) ||
+ value.EqualsLiteral(TEXT_HTML)) {
+ mSelectedFrame = childFrame;
+ break;
+ }
+ }
+ }
+
+ TransmitAutomaticData();
+ return mSelectedFrame;
+}