1 files changed, 88 insertions, 0 deletions
diff --git a/layout/mathml/nsMathMLmunderoverFrame.h b/layout/mathml/nsMathMLmunderoverFrame.h
new file mode 100644
index 0000000000..1282464ed3
--- /dev/null
+++ b/layout/mathml/nsMathMLmunderoverFrame.h
@@ -0,0 +1,88 @@
+/* -*- 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/. */
+
+#ifndef nsMathMLmunderoverFrame_h___
+#define nsMathMLmunderoverFrame_h___
+
+#include "mozilla/Attributes.h"
+#include "nsIReflowCallback.h"
+#include "nsMathMLContainerFrame.h"
+
+namespace mozilla {
+class PresShell;
+}  // namespace mozilla
+
+//
+// <munderover> -- attach an underscript-overscript pair to a base
+//
+
+class nsMathMLmunderoverFrame final : public nsMathMLContainerFrame,
+                                      public nsIReflowCallback {
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(nsMathMLmunderoverFrame)
+
+  friend nsIFrame* NS_NewMathMLmunderoverFrame(mozilla::PresShell* aPresShell,
+                                               ComputedStyle* aStyle);
+
+  nsresult Place(DrawTarget* aDrawTarget, bool aPlaceOrigin,
+                 ReflowOutput& aDesiredSize) override;
+
+  NS_IMETHOD InheritAutomaticData(nsIFrame* aParent) override;
+
+  NS_IMETHOD TransmitAutomaticData() override;
+
+  NS_IMETHOD UpdatePresentationData(uint32_t aFlagsValues,
+                                    uint32_t aFlagsToUpdate) override;
+
+  void Destroy(DestroyContext&) override;
+
+  nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
+                            int32_t aModType) override;
+
+  uint8_t ScriptIncrement(nsIFrame* aFrame) override;
+
+  // nsIReflowCallback.
+  bool ReflowFinished() override;
+  void ReflowCallbackCanceled() override;
+
+ protected:
+  explicit nsMathMLmunderoverFrame(ComputedStyle* aStyle,
+                                   nsPresContext* aPresContext)
+      : nsMathMLContainerFrame(aStyle, aPresContext, kClassID),
+        mIncrementUnder(false),
+        mIncrementOver(false) {}
+
+  virtual ~nsMathMLmunderoverFrame();
+
+ private:
+  // Helper to set the "increment script level" flag on the element belonging
+  // to a child frame given by aChildIndex.
+  //
+  // When this flag is set, the style system will increment the scriptlevel for
+  // the child element. This is needed for situations where the style system
+  // cannot itself determine the scriptlevel (mfrac, munder, mover, munderover).
+  //
+  // This should be called during reflow.
+  //
+  // We set the flag and if it changed, we request appropriate restyling and
+  // also queue a post-reflow callback to ensure that restyle and reflow happens
+  // immediately after the current reflow.
+  void SetIncrementScriptLevel(uint32_t aChildIndex, bool aIncrement);
+  void SetPendingPostReflowIncrementScriptLevel();
+
+  bool mIncrementUnder;
+  bool mIncrementOver;
+
+  struct SetIncrementScriptLevelCommand {
+    uint32_t mChildIndex;
+    bool mDoIncrement;
+  };
+
+  nsTArray<SetIncrementScriptLevelCommand>
+      mPostReflowIncrementScriptLevelCommands;
+};
+
+#endif /* nsMathMLmunderoverFrame_h___ */