layout/generic/nsPlaceholderFrame.h@b8a032363ba2 (annotated)
layout/generic/nsPlaceholderFrame.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | /* |
| michael@0 | 7 | * rendering object for the point that anchors out-of-flow rendering |
| michael@0 | 8 | * objects such as floats and absolutely positioned elements |
| michael@0 | 9 | */ |
| michael@0 | 10 | |
| michael@0 | 11 | /* |
| michael@0 | 12 | * Destruction of a placeholder and its out-of-flow must observe the |
| michael@0 | 13 | * following constraints: |
| michael@0 | 14 | * |
| michael@0 | 15 | * - The mapping from the out-of-flow to the placeholder must be |
| michael@0 | 16 | * removed from the frame manager before the placeholder is destroyed. |
| michael@0 | 17 | * - The mapping from the out-of-flow to the placeholder must be |
| michael@0 | 18 | * removed from the frame manager before the out-of-flow is destroyed. |
| michael@0 | 19 | * - The placeholder must be removed from the frame tree, or have the |
| michael@0 | 20 | * mapping from it to its out-of-flow cleared, before the out-of-flow |
| michael@0 | 21 | * is destroyed (so that the placeholder will not point to a destroyed |
| michael@0 | 22 | * frame while it's in the frame tree). |
| michael@0 | 23 | * |
| michael@0 | 24 | * Furthermore, some code assumes that placeholders point to something |
| michael@0 | 25 | * useful, so placeholders without an associated out-of-flow should not |
| michael@0 | 26 | * remain in the tree. |
| michael@0 | 27 | * |
| michael@0 | 28 | * The placeholder's Destroy() implementation handles the destruction of |
| michael@0 | 29 | * the placeholder and its out-of-flow. To avoid crashes, frame removal |
| michael@0 | 30 | * and destruction code that works with placeholders must not assume |
| michael@0 | 31 | * that the placeholder points to its out-of-flow. |
| michael@0 | 32 | */ |
| michael@0 | 33 | |
| michael@0 | 34 | #ifndef nsPlaceholderFrame_h___ |
| michael@0 | 35 | #define nsPlaceholderFrame_h___ |
| michael@0 | 36 | |
| michael@0 | 37 | #include "mozilla/Attributes.h" |
| michael@0 | 38 | #include "nsFrame.h" |
| michael@0 | 39 | #include "nsGkAtoms.h" |
| michael@0 | 40 | |
| michael@0 | 41 | nsIFrame* NS_NewPlaceholderFrame(nsIPresShell* aPresShell, |
| michael@0 | 42 | nsStyleContext* aContext, |
| michael@0 | 43 | nsFrameState aTypeBit); |
| michael@0 | 44 | |
| michael@0 | 45 | #define PLACEHOLDER_TYPE_MASK (PLACEHOLDER_FOR_FLOAT | \ |
| michael@0 | 46 | PLACEHOLDER_FOR_ABSPOS | \ |
| michael@0 | 47 | PLACEHOLDER_FOR_FIXEDPOS | \ |
| michael@0 | 48 | PLACEHOLDER_FOR_POPUP) |
| michael@0 | 49 | |
| michael@0 | 50 | /** |
| michael@0 | 51 | * Implementation of a frame that's used as a placeholder for a frame that |
| michael@0 | 52 | * has been moved out of the flow. |
| michael@0 | 53 | */ |
| michael@0 | 54 | class nsPlaceholderFrame MOZ_FINAL : public nsFrame { |
| michael@0 | 55 | public: |
| michael@0 | 56 | NS_DECL_FRAMEARENA_HELPERS |
| michael@0 | 57 | #ifdef DEBUG |
| michael@0 | 58 | NS_DECL_QUERYFRAME_TARGET(nsPlaceholderFrame) |
| michael@0 | 59 | NS_DECL_QUERYFRAME |
| michael@0 | 60 | #endif |
| michael@0 | 61 | |
| michael@0 | 62 | /** |
| michael@0 | 63 | * Create a new placeholder frame. aTypeBit must be one of the |
| michael@0 | 64 | * PLACEHOLDER_FOR_* constants above. |
| michael@0 | 65 | */ |
| michael@0 | 66 | friend nsIFrame* NS_NewPlaceholderFrame(nsIPresShell* aPresShell, |
| michael@0 | 67 | nsStyleContext* aContext, |
| michael@0 | 68 | nsFrameState aTypeBit); |
| michael@0 | 69 | nsPlaceholderFrame(nsStyleContext* aContext, nsFrameState aTypeBit) |
| michael@0 | 70 | : nsFrame(aContext) |
| michael@0 | 71 | { |
| michael@0 | 72 | NS_PRECONDITION(aTypeBit == PLACEHOLDER_FOR_FLOAT || |
| michael@0 | 73 | aTypeBit == PLACEHOLDER_FOR_ABSPOS || |
| michael@0 | 74 | aTypeBit == PLACEHOLDER_FOR_FIXEDPOS || |
| michael@0 | 75 | aTypeBit == PLACEHOLDER_FOR_POPUP, |
| michael@0 | 76 | "Unexpected type bit"); |
| michael@0 | 77 | AddStateBits(aTypeBit); |
| michael@0 | 78 | } |
| michael@0 | 79 | |
| michael@0 | 80 | // Get/Set the associated out of flow frame |
| michael@0 | 81 | nsIFrame* GetOutOfFlowFrame() const { return mOutOfFlowFrame; } |
| michael@0 | 82 | void SetOutOfFlowFrame(nsIFrame* aFrame) { |
| michael@0 | 83 | NS_ASSERTION(!aFrame || !aFrame->GetPrevContinuation(), |
| michael@0 | 84 | "OOF must be first continuation"); |
| michael@0 | 85 | mOutOfFlowFrame = aFrame; |
| michael@0 | 86 | } |
| michael@0 | 87 | |
| michael@0 | 88 | // nsIFrame overrides |
| michael@0 | 89 | // We need to override GetMinSize and GetPrefSize because XUL uses |
| michael@0 | 90 | // placeholders not within lines. |
| michael@0 | 91 | virtual void AddInlineMinWidth(nsRenderingContext* aRenderingContext, |
| michael@0 | 92 | InlineMinWidthData* aData) MOZ_OVERRIDE; |
| michael@0 | 93 | virtual void AddInlinePrefWidth(nsRenderingContext* aRenderingContext, |
| michael@0 | 94 | InlinePrefWidthData* aData) MOZ_OVERRIDE; |
| michael@0 | 95 | virtual nsSize GetMinSize(nsBoxLayoutState& aBoxLayoutState) MOZ_OVERRIDE; |
| michael@0 | 96 | virtual nsSize GetPrefSize(nsBoxLayoutState& aBoxLayoutState) MOZ_OVERRIDE; |
| michael@0 | 97 | virtual nsSize GetMaxSize(nsBoxLayoutState& aBoxLayoutState) MOZ_OVERRIDE; |
| michael@0 | 98 | |
| michael@0 | 99 | virtual nsresult Reflow(nsPresContext* aPresContext, |
| michael@0 | 100 | nsHTMLReflowMetrics& aDesiredSize, |
| michael@0 | 101 | const nsHTMLReflowState& aReflowState, |
| michael@0 | 102 | nsReflowStatus& aStatus) MOZ_OVERRIDE; |
| michael@0 | 103 | |
| michael@0 | 104 | virtual void DestroyFrom(nsIFrame* aDestructRoot) MOZ_OVERRIDE; |
| michael@0 | 105 | |
| michael@0 | 106 | #if defined(DEBUG) || (defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF)) |
| michael@0 | 107 | virtual void BuildDisplayList(nsDisplayListBuilder* aBuilder, |
| michael@0 | 108 | const nsRect& aDirtyRect, |
| michael@0 | 109 | const nsDisplayListSet& aLists) MOZ_OVERRIDE; |
| michael@0 | 110 | #endif // DEBUG || (MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF) |
| michael@0 | 111 | |
| michael@0 | 112 | #ifdef DEBUG_FRAME_DUMP |
| michael@0 | 113 | void List(FILE* out = stderr, const char* aPrefix = "", uint32_t aFlags = 0) const MOZ_OVERRIDE; |
| michael@0 | 114 | virtual nsresult GetFrameName(nsAString& aResult) const MOZ_OVERRIDE; |
| michael@0 | 115 | #endif // DEBUG |
| michael@0 | 116 | |
| michael@0 | 117 | /** |
| michael@0 | 118 | * Get the "type" of the frame |
| michael@0 | 119 | * |
| michael@0 | 120 | * @see nsGkAtoms::placeholderFrame |
| michael@0 | 121 | */ |
| michael@0 | 122 | virtual nsIAtom* GetType() const MOZ_OVERRIDE; |
| michael@0 | 123 | |
| michael@0 | 124 | virtual bool IsEmpty() MOZ_OVERRIDE { return true; } |
| michael@0 | 125 | virtual bool IsSelfEmpty() MOZ_OVERRIDE { return true; } |
| michael@0 | 126 | |
| michael@0 | 127 | virtual bool CanContinueTextRun() const MOZ_OVERRIDE; |
| michael@0 | 128 | |
| michael@0 | 129 | #ifdef ACCESSIBILITY |
| michael@0 | 130 | virtual mozilla::a11y::AccType AccessibleType() MOZ_OVERRIDE |
| michael@0 | 131 | { |
| michael@0 | 132 | nsIFrame* realFrame = GetRealFrameForPlaceholder(this); |
| michael@0 | 133 | return realFrame ? realFrame->AccessibleType() : |
| michael@0 | 134 | nsFrame::AccessibleType(); |
| michael@0 | 135 | } |
| michael@0 | 136 | #endif |
| michael@0 | 137 | |
| michael@0 | 138 | virtual nsIFrame* GetParentStyleContextFrame() const MOZ_OVERRIDE; |
| michael@0 | 139 | |
| michael@0 | 140 | /** |
| michael@0 | 141 | * @return the out-of-flow for aFrame if aFrame is a placeholder; otherwise |
| michael@0 | 142 | * aFrame |
| michael@0 | 143 | */ |
| michael@0 | 144 | static nsIFrame* GetRealFrameFor(nsIFrame* aFrame) { |
| michael@0 | 145 | NS_PRECONDITION(aFrame, "Must have a frame to work with"); |
| michael@0 | 146 | if (aFrame->GetType() == nsGkAtoms::placeholderFrame) { |
| michael@0 | 147 | return GetRealFrameForPlaceholder(aFrame); |
| michael@0 | 148 | } |
| michael@0 | 149 | return aFrame; |
| michael@0 | 150 | } |
| michael@0 | 151 | |
| michael@0 | 152 | /** |
| michael@0 | 153 | * @return the out-of-flow for aFrame, which is known to be a placeholder |
| michael@0 | 154 | */ |
| michael@0 | 155 | static nsIFrame* GetRealFrameForPlaceholder(nsIFrame* aFrame) { |
| michael@0 | 156 | NS_PRECONDITION(aFrame->GetType() == nsGkAtoms::placeholderFrame, |
| michael@0 | 157 | "Must have placeholder frame as input"); |
| michael@0 | 158 | nsIFrame* outOfFlow = |
| michael@0 | 159 | static_cast<nsPlaceholderFrame*>(aFrame)->GetOutOfFlowFrame(); |
| michael@0 | 160 | NS_ASSERTION(outOfFlow, "Null out-of-flow for placeholder?"); |
| michael@0 | 161 | return outOfFlow; |
| michael@0 | 162 | } |
| michael@0 | 163 | |
| michael@0 | 164 | protected: |
| michael@0 | 165 | nsIFrame* mOutOfFlowFrame; |
| michael@0 | 166 | }; |
| michael@0 | 167 | |
| michael@0 | 168 | #endif /* nsPlaceholderFrame_h___ */ |
