1 files changed, 228 insertions, 0 deletions
diff --git a/layout/generic/nsPlaceholderFrame.cpp b/layout/generic/nsPlaceholderFrame.cpp
new file mode 100644
index 0000000000..f6b4d53193
--- /dev/null
+++ b/layout/generic/nsPlaceholderFrame.cpp
@@ -0,0 +1,228 @@
+/* -*- 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/. */
+
+/*
+ * rendering object for the point that anchors out-of-flow rendering
+ * objects such as floats and absolutely positioned elements
+ */
+
+#include "nsPlaceholderFrame.h"
+
+#include "gfxContext.h"
+#include "gfxUtils.h"
+#include "mozilla/dom/ElementInlines.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/PresShellInlines.h"
+#include "mozilla/ServoStyleSetInlines.h"
+#include "nsCSSFrameConstructor.h"
+#include "nsDisplayList.h"
+#include "nsLayoutUtils.h"
+#include "nsPresContext.h"
+#include "nsPresContextInlines.h"
+#include "nsIFrameInlines.h"
+#include "nsIContentInlines.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+
+nsPlaceholderFrame* NS_NewPlaceholderFrame(PresShell* aPresShell,
+                                           ComputedStyle* aStyle,
+                                           nsFrameState aTypeBits) {
+  return new (aPresShell)
+      nsPlaceholderFrame(aStyle, aPresShell->GetPresContext(), aTypeBits);
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsPlaceholderFrame)
+
+#ifdef DEBUG
+NS_QUERYFRAME_HEAD(nsPlaceholderFrame)
+  NS_QUERYFRAME_ENTRY(nsPlaceholderFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsIFrame)
+#endif
+
+/* virtual */
+void nsPlaceholderFrame::AddInlineMinISize(
+    gfxContext* aRenderingContext, nsIFrame::InlineMinISizeData* aData) {
+  // Override AddInlineMinWith so that *nothing* happens.  In
+  // particular, we don't want to zero out |aData->mTrailingWhitespace|,
+  // since nsLineLayout skips placeholders when trimming trailing
+  // whitespace, and we don't want to set aData->mSkipWhitespace to
+  // false.
+
+  // ...but push floats onto the list
+  if (mOutOfFlowFrame->IsFloating()) {
+    nscoord floatWidth = nsLayoutUtils::IntrinsicForContainer(
+        aRenderingContext, mOutOfFlowFrame, IntrinsicISizeType::MinISize);
+    aData->mFloats.AppendElement(
+        InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
+  }
+}
+
+/* virtual */
+void nsPlaceholderFrame::AddInlinePrefISize(
+    gfxContext* aRenderingContext, nsIFrame::InlinePrefISizeData* aData) {
+  // Override AddInlinePrefWith so that *nothing* happens.  In
+  // particular, we don't want to zero out |aData->mTrailingWhitespace|,
+  // since nsLineLayout skips placeholders when trimming trailing
+  // whitespace, and we don't want to set aData->mSkipWhitespace to
+  // false.
+
+  // ...but push floats onto the list
+  if (mOutOfFlowFrame->IsFloating()) {
+    nscoord floatWidth = nsLayoutUtils::IntrinsicForContainer(
+        aRenderingContext, mOutOfFlowFrame, IntrinsicISizeType::PrefISize);
+    aData->mFloats.AppendElement(
+        InlineIntrinsicISizeData::FloatInfo(mOutOfFlowFrame, floatWidth));
+  }
+}
+
+void nsPlaceholderFrame::Reflow(nsPresContext* aPresContext,
+                                ReflowOutput& aDesiredSize,
+                                const ReflowInput& aReflowInput,
+                                nsReflowStatus& aStatus) {
+  // NOTE that the ReflowInput passed to this method is not fully initialized,
+  // on the grounds that reflowing a placeholder is a rather trivial operation.
+  // (See bug 1367711.)
+
+#ifdef DEBUG
+  // We should be getting reflowed before our out-of-flow. If this is our first
+  // reflow, and our out-of-flow has already received its first reflow (before
+  // us), complain.
+  //
+  // Popups are an exception though, because their position doesn't depend on
+  // the placeholder, so they don't have this requirement (and this condition
+  // doesn't hold anyways because the default popupgroup goes before than the
+  // default tooltip, for example).
+  if (HasAnyStateBits(NS_FRAME_FIRST_REFLOW) &&
+      !mOutOfFlowFrame->IsMenuPopupFrame() &&
+      !mOutOfFlowFrame->HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
+    // Unfortunately, this can currently happen when the placeholder is in a
+    // later continuation or later IB-split sibling than its out-of-flow (as
+    // is the case in some of our existing unit tests). So for now, in that
+    // case, we'll warn instead of asserting.
+    bool isInContinuationOrIBSplit = false;
+    nsIFrame* ancestor = this;
+    while ((ancestor = ancestor->GetParent())) {
+      if (nsLayoutUtils::GetPrevContinuationOrIBSplitSibling(ancestor)) {
+        isInContinuationOrIBSplit = true;
+        break;
+      }
+    }
+
+    if (isInContinuationOrIBSplit) {
+      NS_WARNING("Out-of-flow frame got reflowed before its placeholder");
+    } else {
+      NS_ERROR("Out-of-flow frame got reflowed before its placeholder");
+    }
+  }
+#endif
+
+  MarkInReflow();
+  DO_GLOBAL_REFLOW_COUNT("nsPlaceholderFrame");
+  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);
+  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+  aDesiredSize.ClearSize();
+}
+
+static FrameChildListID ChildListIDForOutOfFlow(nsFrameState aPlaceholderState,
+                                                const nsIFrame* aChild) {
+  if (aPlaceholderState & PLACEHOLDER_FOR_FLOAT) {
+    return FrameChildListID::Float;
+  }
+  if (aPlaceholderState & PLACEHOLDER_FOR_FIXEDPOS) {
+    return nsLayoutUtils::MayBeReallyFixedPos(aChild)
+               ? FrameChildListID::Fixed
+               : FrameChildListID::Absolute;
+  }
+  if (aPlaceholderState & PLACEHOLDER_FOR_ABSPOS) {
+    return FrameChildListID::Absolute;
+  }
+  MOZ_DIAGNOSTIC_ASSERT(false, "unknown list");
+  return FrameChildListID::Float;
+}
+
+void nsPlaceholderFrame::Destroy(DestroyContext& aContext) {
+  if (nsIFrame* oof = mOutOfFlowFrame) {
+    mOutOfFlowFrame = nullptr;
+    oof->RemoveProperty(nsIFrame::PlaceholderFrameProperty());
+
+    // Destroy the out of flow now.
+    ChildListID listId = ChildListIDForOutOfFlow(GetStateBits(), oof);
+    nsFrameManager* fm = PresContext()->FrameConstructor();
+    fm->RemoveFrame(aContext, listId, oof);
+  }
+
+  nsIFrame::Destroy(aContext);
+}
+
+/* virtual */
+bool nsPlaceholderFrame::CanContinueTextRun() const {
+  if (!mOutOfFlowFrame) {
+    return false;
+  }
+  // first-letter frames can continue text runs, and placeholders for floated
+  // first-letter frames can too
+  return mOutOfFlowFrame->CanContinueTextRun();
+}
+
+ComputedStyle* nsPlaceholderFrame::GetParentComputedStyleForOutOfFlow(
+    nsIFrame** aProviderFrame) const {
+  MOZ_ASSERT(GetParent(), "How can we not have a parent here?");
+
+  Element* parentElement =
+      mContent ? mContent->GetFlattenedTreeParentElement() : nullptr;
+  // See the similar code in nsIFrame::DoGetParentComputedStyle.
+  if (parentElement && MOZ_LIKELY(parentElement->HasServoData()) &&
+      Servo_Element_IsDisplayContents(parentElement)) {
+    RefPtr<ComputedStyle> style =
+        ServoStyleSet::ResolveServoStyle(*parentElement);
+    *aProviderFrame = nullptr;
+    // See the comment in GetParentComputedStyle to see why returning this as a
+    // weak ref is fine.
+    return style;
+  }
+
+  return GetLayoutParentStyleForOutOfFlow(aProviderFrame);
+}
+
+ComputedStyle* nsPlaceholderFrame::GetLayoutParentStyleForOutOfFlow(
+    nsIFrame** aProviderFrame) const {
+  // Lie about our pseudo so we can step out of all anon boxes and
+  // pseudo-elements.  The other option would be to reimplement the
+  // {ib} split gunk here.
+  //
+  // See the hack in CorrectStyleParentFrame for why we pass `MAX`.
+  *aProviderFrame = CorrectStyleParentFrame(GetParent(), PseudoStyleType::MAX);
+  return *aProviderFrame ? (*aProviderFrame)->Style() : nullptr;
+}
+
+#if defined(DEBUG) || (defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF))
+
+void nsPlaceholderFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                                          const nsDisplayListSet& aLists) {
+  DO_GLOBAL_REFLOW_COUNT_DSP("nsPlaceholderFrame");
+}
+#endif  // DEBUG || (MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF)
+
+#ifdef DEBUG_FRAME_DUMP
+nsresult nsPlaceholderFrame::GetFrameName(nsAString& aResult) const {
+  return MakeFrameName(u"Placeholder"_ns, aResult);
+}
+
+void nsPlaceholderFrame::List(FILE* out, const char* aPrefix,
+                              ListFlags aFlags) const {
+  nsCString str;
+  ListGeneric(str, aPrefix, aFlags);
+
+  if (mOutOfFlowFrame) {
+    str += " outOfFlowFrame=";
+    str += mOutOfFlowFrame->ListTag();
+  }
+  fprintf_stderr(out, "%s\n", str.get());
+}
+#endif