/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is mozilla.org code. * * The Initial Developer of the Original Code is * Netscape Communications Corporation. * Portions created by the Initial Developer are Copyright (C) 1998 * the Initial Developer. All Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the terms of * either of the GNU General Public License Version 2 or later (the "GPL"), * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ /* * 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). * * Therefore the safe order of teardown is to: * * 1) Unregister the placeholder from the frame manager. * 2) Destroy the placeholder * 3) Destroy the out of flow * * In certain cases it may be possible to replace step (2) with: * * 2') Null out the mOutOfFlowFrame pointer in the placeholder * * and add * * 4) Destroy the placeholder * * but this is somewhat dangerous, since lots of code assumes that * placeholders point to something useful. */ #ifndef nsPlaceholderFrame_h___ #define nsPlaceholderFrame_h___ #include "nsFrame.h" #include "nsGkAtoms.h" nsIFrame* NS_NewPlaceholderFrame(nsIPresShell* aPresShell, nsStyleContext* aContext, nsFrameState aTypeBit); // Frame state bits that are used to keep track of what this is a // placeholder for. #define PLACEHOLDER_FOR_FLOAT 0x00100000 #define PLACEHOLDER_FOR_ABSPOS 0x00200000 #define PLACEHOLDER_FOR_FIXEDPOS 0x00400000 #define PLACEHOLDER_FOR_POPUP 0x00800000 #define PLACEHOLDER_TYPE_MASK 0x00F00000 /** * Implementation of a frame that's used as a placeholder for a frame that * has been moved out of the flow */ class nsPlaceholderFrame : public nsFrame { public: NS_DECL_FRAMEARENA_HELPERS /** * Create a new placeholder frame. aTypeBit must be one of the * PLACEHOLDER_FOR_* constants above. */ friend nsIFrame* NS_NewPlaceholderFrame(nsIPresShell* aPresShell, nsStyleContext* aContext, nsFrameState aTypeBit); nsPlaceholderFrame(nsStyleContext* aContext, nsFrameState aTypeBit) : nsFrame(aContext) { NS_PRECONDITION(aTypeBit == PLACEHOLDER_FOR_FLOAT || aTypeBit == PLACEHOLDER_FOR_ABSPOS || aTypeBit == PLACEHOLDER_FOR_FIXEDPOS || aTypeBit == PLACEHOLDER_FOR_POPUP, "Unexpected type bit"); AddStateBits(aTypeBit); } virtual ~nsPlaceholderFrame(); // 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; } // nsIHTMLReflow overrides // We need to override GetMinWidth and GetPrefWidth because XUL uses // placeholders not within lines. virtual nscoord GetMinWidth(nsIRenderingContext *aRenderingContext); virtual nscoord GetPrefWidth(nsIRenderingContext *aRenderingContext); virtual void AddInlineMinWidth(nsIRenderingContext *aRenderingContext, InlineMinWidthData *aData); virtual void AddInlinePrefWidth(nsIRenderingContext *aRenderingContext, InlinePrefWidthData *aData); NS_IMETHOD Reflow(nsPresContext* aPresContext, nsHTMLReflowMetrics& aDesiredSize, const nsHTMLReflowState& aReflowState, nsReflowStatus& aStatus); virtual void Destroy(); // nsIFrame overrides #if defined(DEBUG) || (defined(MOZ_REFLOW_PERF_DSP) && defined(MOZ_REFLOW_PERF)) NS_IMETHOD BuildDisplayList(nsDisplayListBuilder* aBuilder, const nsRect& aDirtyRect, const nsDisplayListSet& aLists); #endif // DEBUG || (MOZ_REFLOW_PERF_DSP && MOZ_REFLOW_PERF) #ifdef DEBUG NS_IMETHOD List(FILE* out, PRInt32 aIndent) const; #endif // DEBUG /** * Get the "type" of the frame * * @see nsGkAtoms::placeholderFrame */ virtual nsIAtom* GetType() const; #ifdef DEBUG NS_IMETHOD GetFrameName(nsAString& aResult) const; #endif virtual PRBool IsEmpty() { return PR_TRUE; } virtual PRBool IsSelfEmpty() { return PR_TRUE; } virtual PRBool CanContinueTextRun() const; #ifdef ACCESSIBILITY NS_IMETHOD GetAccessible(nsIAccessible** aAccessible) { nsIFrame *realFrame = GetRealFrameForPlaceholder(this); return realFrame ? realFrame->GetAccessible(aAccessible) : nsFrame::GetAccessible(aAccessible); } #endif NS_IMETHOD GetParentStyleContextFrame(nsPresContext* aPresContext, nsIFrame** aProviderFrame, PRBool* aIsChild); /** * @return the out-of-flow for aFrame if aFrame is a placeholder; otherwise * aFrame */ static nsIFrame* GetRealFrameFor(nsIFrame* aFrame) { NS_PRECONDITION(aFrame, "Must have a frame to work with"); if (aFrame->GetType() == nsGkAtoms::placeholderFrame) { return GetRealFrameForPlaceholder(aFrame); } return aFrame; } /** * @return the out-of-flow for aFrame, which is known to be a placeholder */ static nsIFrame* GetRealFrameForPlaceholder(nsIFrame* aFrame) { NS_PRECONDITION(aFrame->GetType() == nsGkAtoms::placeholderFrame, "Must have placeholder frame as input"); nsIFrame* outOfFlow = static_cast(aFrame)->GetOutOfFlowFrame(); NS_ASSERTION(outOfFlow, "Null out-of-flow for placeholder?"); return outOfFlow; } protected: nsIFrame* mOutOfFlowFrame; }; #endif /* nsPlaceholderFrame_h___ */