/* -*- 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 "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->GetParent() &&
             aFrame->PresContext()->FrameConstructor()->
               GetDisplayContentsStyleFor(aContent->GetParent())) ||
             (aContent->IsNodeOfType(nsINode::eTEXT) &&
              aContent->IsStyledByServo() &&
              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.
    if (IsServo()) {
      // 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
    } else {
      // Filter out all other changes for same content for Gecko (Servo asserts against this
      // case above).
      // NOTE: This is captured by reference to please static analysis.
      // Capturing it by value as a pointer should be fine in this case.
      RemoveElementsBy([&](const nsStyleChangeData& aData) {
        return aData.mContent == aContent;
      });
    }
  }

  if (!IsEmpty() && aFrame && aFrame == LastElement().mFrame) {
    LastElement().mHint |= aHint;
    return;
  }

  AppendElement(nsStyleChangeData { aFrame, aContent, aHint });
}