Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 187 insertions, 0 deletions

diff --git a/layout/generic/nsPlaceholderFrame.h b/layout/generic/nsPlaceholderFrame.h
new file mode 100644
index 0000000000..4cbb54259a
--- /dev/null
+++ b/layout/generic/nsPlaceholderFrame.h
@@ -0,0 +1,187 @@
+/* -*- 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
+ */
+
+/*
+ * Destruction of a placeholder and its out-of-flow must observe the
+ * following constraints:
+ *
+ * - The mapping from the out-of-flow to the placeholder must be
+ *   removed from the frame manager before the placeholder is destroyed.
+ * - The mapping from the out-of-flow to the placeholder must be
+ *   removed from the frame manager before the out-of-flow is destroyed.
+ * - The placeholder must be removed from the frame tree, or have the
+ *   mapping from it to its out-of-flow cleared, before the out-of-flow
+ *   is destroyed (so that the placeholder will not point to a destroyed
+ *   frame while it's in the frame tree).
+ *
+ * Furthermore, some code assumes that placeholders point to something
+ * useful, so placeholders without an associated out-of-flow should not
+ * remain in the tree.
+ *
+ * The placeholder's Destroy() implementation handles the destruction of
+ * the placeholder and its out-of-flow. To avoid crashes, frame removal
+ * and destruction code that works with placeholders must not assume
+ * that the placeholder points to its out-of-flow.
+ */
+
+#ifndef nsPlaceholderFrame_h___
+#define nsPlaceholderFrame_h___
+
+#include "mozilla/Attributes.h"
+#include "nsIFrame.h"
+#include "nsGkAtoms.h"
+
+namespace mozilla {
+class PresShell;
+}  // namespace mozilla
+
+class nsPlaceholderFrame;
+nsPlaceholderFrame* NS_NewPlaceholderFrame(mozilla::PresShell* aPresShell,
+                                           mozilla::ComputedStyle* aStyle,
+                                           nsFrameState aTypeBits);
+
+#define PLACEHOLDER_TYPE_MASK                                                  \
+  (PLACEHOLDER_FOR_FLOAT | PLACEHOLDER_FOR_ABSPOS | PLACEHOLDER_FOR_FIXEDPOS | \
+   PLACEHOLDER_FOR_TOPLAYER)
+
+/**
+ * Implementation of a frame that's used as a placeholder for a frame that
+ * has been moved out of the flow.
+ */
+class nsPlaceholderFrame final : public nsIFrame {
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(nsPlaceholderFrame)
+#ifdef DEBUG
+  NS_DECL_QUERYFRAME
+#endif
+
+  /**
+   * Create a new placeholder frame.  aTypeBit must be one of the
+   * PLACEHOLDER_FOR_* constants above.
+   */
+  friend nsPlaceholderFrame* NS_NewPlaceholderFrame(
+      mozilla::PresShell* aPresShell, ComputedStyle* aStyle,
+      nsFrameState aTypeBits);
+
+  nsPlaceholderFrame(ComputedStyle* aStyle, nsPresContext* aPresContext,
+                     nsFrameState aTypeBits)
+      : nsIFrame(aStyle, aPresContext, kClassID), mOutOfFlowFrame(nullptr) {
+    MOZ_ASSERT(
+        aTypeBits == PLACEHOLDER_FOR_FLOAT ||
+            aTypeBits == PLACEHOLDER_FOR_ABSPOS ||
+            aTypeBits == PLACEHOLDER_FOR_FIXEDPOS ||
+            aTypeBits == (PLACEHOLDER_FOR_TOPLAYER | PLACEHOLDER_FOR_ABSPOS) ||
+            aTypeBits == (PLACEHOLDER_FOR_TOPLAYER | PLACEHOLDER_FOR_FIXEDPOS),
+        "Unexpected type bit");
+    AddStateBits(aTypeBits);
+  }
+
+  // Get/Set the associated out of flow frame
+  nsIFrame* GetOutOfFlowFrame() const { return mOutOfFlowFrame; }
+  void SetOutOfFlowFrame(nsIFrame* aFrame) {
+    NS_ASSERTION(!aFrame || !aFrame->GetPrevContinuation(),
+                 "OOF must be first continuation");
+    mOutOfFlowFrame = aFrame;
+  }
+
+  // nsIFrame overrides
+  void AddInlineMinISize(gfxContext* aRenderingContext,
+                         InlineMinISizeData* aData) override;
+  void AddInlinePrefISize(gfxContext* aRenderingContext,
+                          InlinePrefISizeData* aData) override;
+
+  void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
+              const ReflowInput& aReflowInput,
+              nsReflowStatus& aStatus) override;
+
+  void Destroy(DestroyContext&) override;
+
+#if defined(DEBUG) || (defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF))
+  void BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                        const nsDisplayListSet& aLists) override;
+#endif  // DEBUG || (MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF)
+
+#ifdef DEBUG_FRAME_DUMP
+  void List(FILE* out = stderr, const char* aPrefix = "",
+            ListFlags aFlags = ListFlags()) const override;
+  nsresult GetFrameName(nsAString& aResult) const override;
+#endif  // DEBUG
+
+  bool IsEmpty() override { return true; }
+  bool IsSelfEmpty() override { return true; }
+
+  bool CanContinueTextRun() const override;
+
+  void SetLineIsEmptySoFar(bool aValue) {
+    AddOrRemoveStateBits(PLACEHOLDER_LINE_IS_EMPTY_SO_FAR, aValue);
+    AddStateBits(PLACEHOLDER_HAVE_LINE_IS_EMPTY_SO_FAR);
+  }
+  bool GetLineIsEmptySoFar(bool* aResult) const {
+    bool haveValue = HasAnyStateBits(PLACEHOLDER_HAVE_LINE_IS_EMPTY_SO_FAR);
+    if (haveValue) {
+      *aResult = HasAnyStateBits(PLACEHOLDER_LINE_IS_EMPTY_SO_FAR);
+    }
+    return haveValue;
+  }
+  void ForgetLineIsEmptySoFar() {
+    RemoveStateBits(PLACEHOLDER_HAVE_LINE_IS_EMPTY_SO_FAR);
+  }
+
+#ifdef ACCESSIBILITY
+  mozilla::a11y::AccType AccessibleType() override {
+    nsIFrame* realFrame = GetRealFrameForPlaceholder(this);
+    return realFrame ? realFrame->AccessibleType() : nsIFrame::AccessibleType();
+  }
+#endif
+
+  ComputedStyle* GetParentComputedStyleForOutOfFlow(
+      nsIFrame** aProviderFrame) const;
+
+  // Like GetParentComputedStyleForOutOfFlow, but ignores display:contents bits.
+  ComputedStyle* GetLayoutParentStyleForOutOfFlow(
+      nsIFrame** aProviderFrame) const;
+
+  bool RenumberFrameAndDescendants(int32_t* aOrdinal, int32_t aDepth,
+                                   int32_t aIncrement,
+                                   bool aForCounting) override {
+    return mOutOfFlowFrame->RenumberFrameAndDescendants(
+        aOrdinal, aDepth, aIncrement, aForCounting);
+  }
+
+  /**
+   * @return the out-of-flow for aFrame if aFrame is a placeholder; otherwise
+   * aFrame
+   */
+  static nsIFrame* GetRealFrameFor(nsIFrame* aFrame) {
+    MOZ_ASSERT(aFrame, "Must have a frame to work with");
+    if (aFrame->IsPlaceholderFrame()) {
+      return GetRealFrameForPlaceholder(aFrame);
+    }
+    return aFrame;
+  }
+
+  /**
+   * @return the out-of-flow for aFrame, which is known to be a placeholder
+   */
+  static nsIFrame* GetRealFrameForPlaceholder(nsIFrame* aFrame) {
+    MOZ_ASSERT(aFrame->IsPlaceholderFrame(),
+               "Must have placeholder frame as input");
+    nsIFrame* outOfFlow =
+        static_cast<nsPlaceholderFrame*>(aFrame)->GetOutOfFlowFrame();
+    NS_ASSERTION(outOfFlow, "Null out-of-flow for placeholder?");
+    return outOfFlow;
+  }
+
+ protected:
+  nsIFrame* mOutOfFlowFrame;
+};
+
+#endif /* nsPlaceholderFrame_h___ */