140 lines
4.4 KiB
C++
140 lines
4.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsILineIterator_h___
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#define nsILineIterator_h___
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#include "nscore.h"
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#include "nsINode.h"
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#include "nsRect.h"
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#include "mozilla/Attributes.h"
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#include "mozilla/Result.h"
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#include "mozilla/WritingModes.h"
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class nsIFrame;
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/**
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* Line iterator API.
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*
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* Lines are numbered from 0 to N, where 0 is the top line and N is
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* the bottom line.
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*
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* Obtain this interface from frames via nsIFrame::GetLineIterator.
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* This iterator belongs to the frame from which it was obtained, and should
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* not be deleted by the caller.
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* Note that any modification of the frame will invalidate the iterator!
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* Users must get a new iterator any time the target may have been touched.
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*/
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class nsILineIterator {
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protected:
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~nsILineIterator() = default;
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public:
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/**
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* The number of lines in the block
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*/
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virtual int32_t GetNumLines() const = 0;
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/**
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* Returns whether our lines are rtl.
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*/
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virtual bool IsLineIteratorFlowRTL() = 0;
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struct LineInfo {
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/** The first frame on the line. */
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nsIFrame* mFirstFrameOnLine = nullptr;
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/** The numbers of frames on the line. */
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int32_t mNumFramesOnLine = 0;
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/**
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* The bounding box of the line (which is based on the in-flow position of
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* the frames on the line; if a frame was moved because of relative
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* positioning then its coordinates may be outside the line bounds)
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*/
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nsRect mLineBounds;
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/** Whether the line is wrapped at the end */
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bool mIsWrapped = false;
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/**
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* Return last frame of the line if there is no enough siblings of
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* mFirstFrameOnLine.
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* Otherwise, nullptr including in the unexpected error cases.
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*/
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nsIFrame* GetLastFrameOnLine() const;
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};
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// Return miscellaneous information about a line.
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virtual mozilla::Result<LineInfo, nsresult> GetLine(int32_t aLineNumber) = 0;
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/**
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* Given a frame that's a child of the block, find which line its on
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* and return that line index, as long as it's at least as big as
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* aStartLine. Returns -1 if the frame cannot be found on lines
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* starting with aStartLine.
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*/
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virtual int32_t FindLineContaining(nsIFrame* aFrame,
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int32_t aStartLine = 0) = 0;
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// Given a line number and a coordinate, find the frame on the line
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// that is nearest to aPos along the inline axis. (The block-axis coord
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// of aPos is irrelevant.)
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// The aPosIsBeforeFirstFrame and aPosIsAfterLastFrame flags are updated
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// appropriately.
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NS_IMETHOD FindFrameAt(int32_t aLineNumber, nsPoint aPos,
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nsIFrame** aFrameFound, bool* aPosIsBeforeFirstFrame,
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bool* aPosIsAfterLastFrame) = 0;
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// Check whether visual and logical order of frames within a line are
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// identical.
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// If not, return the first and last visual frames
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NS_IMETHOD CheckLineOrder(int32_t aLine, bool* aIsReordered,
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nsIFrame** aFirstVisual,
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nsIFrame** aLastVisual) = 0;
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};
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namespace mozilla {
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// Helper struct for FindFrameAt.
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struct LineFrameFinder {
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LineFrameFinder(const nsPoint& aPos, const nsSize& aContainerSize,
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WritingMode aWM, bool aIsReversed)
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: mPos(aWM, aPos, aContainerSize),
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mContainerSize(aContainerSize),
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mWM(aWM),
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mIsReversed(aIsReversed) {}
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void Scan(nsIFrame*);
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void Finish(nsIFrame**, bool* aPosIsBeforeFirstFrame,
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bool* aPosIsAfterLastFrame);
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const LogicalPoint mPos;
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const nsSize mContainerSize;
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const WritingMode mWM;
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const bool mIsReversed;
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bool IsDone() const { return mDone; }
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private:
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bool mDone = false;
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nsIFrame* mFirstFrame = nullptr;
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nsIFrame* mClosestFromStart = nullptr;
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nsIFrame* mClosestFromEnd = nullptr;
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};
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} // namespace mozilla
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/**
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* Helper intended to be used in a scope where we're using an nsILineIterator
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* and want to verify that no DOM mutations (which would invalidate the
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* iterator) occur while we're using it.
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*/
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class MOZ_RAII AutoAssertNoDomMutations final {
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#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
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nsMutationGuard mGuard;
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#endif
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public:
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~AutoAssertNoDomMutations() { MOZ_DIAGNOSTIC_ASSERT(!mGuard.Mutated(0)); }
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};
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#endif /* nsILineIterator_h___ */
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