зеркало из https://github.com/mozilla/pjs.git
196 строки
7.7 KiB
C++
196 строки
7.7 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla.org code.
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*
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* The Initial Developer of the Original Code is
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* Boris Zbarsky <bzbarsky@mit.edu>.
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* Portions created by the Initial Developer are Copyright (C) 2002
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsLayoutUtils_h__
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#define nsLayoutUtils_h__
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class nsIFrame;
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class nsIPresContext;
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class nsIContent;
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class nsIAtom;
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class nsIView;
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#include "prtypes.h"
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#include "nsStyleContext.h"
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#include "nsAutoPtr.h"
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#include "nsStyleSet.h"
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/**
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* nsLayoutUtils is a namespace class used for various helper
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* functions that are useful in multiple places in layout. The goal
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* is not to define multiple copies of the same static helper.
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*/
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class nsLayoutUtils
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{
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public:
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/**
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* GetBeforeFrame returns the :before frame of the given frame, if
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* one exists. This is typically O(1). The frame passed in must be
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* the first-in-flow.
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*
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* @param aFrame the frame whose :before is wanted
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* @param aPresContext the prescontext
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* @return the :before frame or nsnull if there isn't one
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*/
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static nsIFrame* GetBeforeFrame(nsIFrame* aFrame, nsIPresContext* aPresContext);
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/**
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* GetAfterFrame returns the :after frame of the given frame, if one
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* exists. This will walk the in-flow chain to the last-in-flow if
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* needed. This function is typically O(N) in the number of child
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* frames, following in-flows, etc.
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*
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* @param aFrame the frame whose :after is wanted
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* @param aPresContext the prescontext
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* @return the :after frame or nsnull if there isn't one
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*/
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static nsIFrame* GetAfterFrame(nsIFrame* aFrame, nsIPresContext* aPresContext);
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/**
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* Given a frame, search up the frame tree until we find an
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* ancestor "Page" frame, if any.
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*
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* @param the frame to start at
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* @return a frame of type nsLayoutAtoms::pageFrame or nsnull if no
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* such ancestor exists
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*/
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static nsIFrame* GetPageFrame(nsIFrame* aFrame);
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/**
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* IsGeneratedContentFor returns PR_TRUE if aFrame is generated
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* content of type aPseudoElement for aContent
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*
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* @param aContent the content node we're looking at. If this is
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* null, then we just assume that aFrame has the right content
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* pointer.
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* @param aFrame the frame we're looking at
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* @param aPseudoElement the pseudo type we're interested in
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* @return whether aFrame is the generated aPseudoElement frame for aContent
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*/
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static PRBool IsGeneratedContentFor(nsIContent* aContent, nsIFrame* aFrame,
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nsIAtom* aPseudoElement);
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/**
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* CompareTreePosition determines whether aContent1 comes before or
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* after aContent2 in a preorder traversal of the content tree.
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*
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* @param aCommonAncestor either null, or a common ancestor of
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* aContent1 and aContent2. Actually this is
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* only a hint; if it's not an ancestor of
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* aContent1 or aContent2, this function will
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* still work, but it will be slower than
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* normal.
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* @return < 0 if aContent1 is before aContent2
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* > 0 if aContent1 is after aContent2,
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* 0 otherwise (meaning they're the same, or they're in
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* different documents)
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*/
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static PRInt32 CompareTreePosition(nsIContent* aContent1,
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nsIContent* aContent2,
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nsIContent* aCommonAncestor = nsnull)
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{
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return DoCompareTreePosition(aContent1, aContent2, -1, 1, aCommonAncestor);
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}
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/*
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* More generic version of |CompareTreePosition|. |aIf1Ancestor|
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* gives the value to return when 1 is an ancestor of 2, and likewise
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* for |aIf2Ancestor|. Passing (-1, 1) gives preorder traversal
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* order, and (1, -1) gives postorder traversal order.
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*/
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static PRInt32 DoCompareTreePosition(nsIContent* aContent1,
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nsIContent* aContent2,
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PRInt32 aIf1Ancestor,
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PRInt32 aIf2Ancestor,
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nsIContent* aCommonAncestor = nsnull);
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/**
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* GetLastSibling simply finds the last sibling of aFrame, or returns nsnull if
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* aFrame is null.
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*/
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static nsIFrame* GetLastSibling(nsIFrame* aFrame);
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/**
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* FindSiblingViewFor locates the child of aParentView that aFrame's
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* view should be inserted 'above' (i.e., before in sibling view
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* order). This is the first child view of aParentView whose
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* corresponding content is before aFrame's content (view siblings
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* are in reverse content order).
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*/
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static nsIView* FindSiblingViewFor(nsIView* aParentView, nsIFrame* aFrame);
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/**
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* IsProperAncestorFrame checks whether aAncestorFrame is an ancestor
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* of aFrame and not equal to aFrame.
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* @param aCommonAncestor nsnull, or a common ancestor of aFrame and
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* aAncestorFrame. If non-null, this can bound the search and speed up
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* the function
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*/
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static PRBool IsProperAncestorFrame(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
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nsIFrame* aCommonAncestor = nsnull);
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/**
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* HasPseudoStyle returns PR_TRUE if aContent (whose primary style
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* context is aStyleContext) has the aPseudoElement pseudo-style
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* attached to it; returns PR_FALSE otherwise.
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*
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* @param aContent the content node we're looking at
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* @param aStyleContext aContent's style context
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* @param aPseudoElement the name of the pseudo style we care about
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* @param aPresContext the presentation context
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* @return whether aContent has aPseudoElement style attached to it
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*/
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static PRBool HasPseudoStyle(nsIContent* aContent,
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nsStyleContext* aStyleContext,
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nsIAtom* aPseudoElement,
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nsIPresContext* aPresContext)
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{
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NS_PRECONDITION(aPresContext, "Must have a prescontext");
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NS_PRECONDITION(aPseudoElement, "Must have a pseudo name");
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nsRefPtr<nsStyleContext> pseudoContext;
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if (aContent) {
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pseudoContext = aPresContext->StyleSet()->
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ProbePseudoStyleFor(aContent, aPseudoElement, aStyleContext);
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}
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return pseudoContext != nsnull;
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}
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};
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#endif // nsLayoutUtils_h__
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