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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 01:47:29 +0000 |
commit | 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch) | |
tree | a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /layout/generic/nsPlaceholderFrame.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip |
Adding upstream version 115.8.0esr.upstream/115.8.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'layout/generic/nsPlaceholderFrame.h')
-rw-r--r-- | layout/generic/nsPlaceholderFrame.h | 187 |
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___ */ |