1 files changed, 72 insertions, 0 deletions
diff --git a/layout/base/nsStyleChangeList.cpp b/layout/base/nsStyleChangeList.cpp
new file mode 100644
index 0000000000..d41ee99195
--- /dev/null
+++ b/layout/base/nsStyleChangeList.cpp
@@ -0,0 +1,72 @@
+/* -*- 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/. */
+
+/*
+ * a list of the recomputation that needs to be done in response to a
+ * style change
+ */
+
+#include "nsStyleChangeList.h"
+
+#include "mozilla/dom/ElementInlines.h"
+
+#include "nsCSSFrameConstructor.h"
+#include "nsIContent.h"
+#include "nsIFrame.h"
+
+void nsStyleChangeList::AppendChange(nsIFrame* aFrame, nsIContent* aContent,
+                                     nsChangeHint aHint) {
+  MOZ_ASSERT(aFrame || (aHint & nsChangeHint_ReconstructFrame),
+             "must have frame");
+  MOZ_ASSERT(aHint, "No hint to process?");
+  MOZ_ASSERT(!(aHint & nsChangeHint_NeutralChange),
+             "Neutral changes do not need extra processing, "
+             "and should be stripped out");
+  MOZ_ASSERT(aContent || !(aHint & nsChangeHint_ReconstructFrame),
+             "must have content");
+  // XXXbz we should make this take Element instead of nsIContent
+  MOZ_ASSERT(
+      !aContent || aContent->IsElement() ||
+          // display:contents elements posts the changes for their children:
+          (aFrame && aContent->GetFlattenedTreeParentElementForStyle() &&
+           Servo_Element_IsDisplayContents(
+               aContent->GetFlattenedTreeParentElementForStyle())) ||
+          (aContent->IsText() && aContent->HasFlag(NODE_NEEDS_FRAME) &&
+           aHint & nsChangeHint_ReconstructFrame),
+      "Shouldn't be trying to restyle non-elements directly, "
+      "except if it's a display:contents child or a text node "
+      "doing lazy frame construction");
+  MOZ_ASSERT(!(aHint & nsChangeHint_AllReflowHints) ||
+                 (aHint & nsChangeHint_NeedReflow),
+             "Reflow hint bits set without actually asking for a reflow");
+
+  if (aHint & nsChangeHint_ReconstructFrame) {
+    // If Servo fires reconstruct at a node, it is the only change hint fired at
+    // that node.
+
+    // Note: Because we check whether |aHint| is a reconstruct above (which is
+    // necessary to avoid debug test timeouts on certain crashtests), this check
+    // will not find bugs where we add a non-reconstruct hint for an element
+    // after adding a reconstruct. This is ok though, since
+    // ProcessRestyledFrames will handle that case via mDestroyedFrames.
+#ifdef DEBUG
+    for (size_t i = 0; i < Length(); ++i) {
+      MOZ_ASSERT(aContent != (*this)[i].mContent ||
+                     !((*this)[i].mHint & nsChangeHint_ReconstructFrame),
+                 "Should not append a non-ReconstructFrame hint after \
+                 appending a ReconstructFrame hint for the same \
+                 content.");
+    }
+#endif
+  }
+
+  if (!IsEmpty() && aFrame && aFrame == LastElement().mFrame) {
+    LastElement().mHint |= aHint;
+    return;
+  }
+
+  AppendElement(nsStyleChangeData{aFrame, aContent, aHint});
+}