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/* -*- 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 */
#ifndef mozilla_SelectionMovementUtils_h
#define mozilla_SelectionMovementUtils_h
#include "mozilla/intl/BidiEmbeddingLevel.h"
#include "mozilla/Attributes.h"
#include "mozilla/EnumSet.h"
#include "mozilla/Result.h"
#include "nsIFrame.h"
struct nsPrevNextBidiLevels;
namespace mozilla {
class PresShell;
enum class PeekOffsetOption : uint16_t;
namespace intl {
class BidiEmbeddingLevel;
struct MOZ_STACK_CLASS PrimaryFrameData {
// The frame which should be used to layout the caret.
nsIFrame* mFrame = nullptr;
// The offset in content of mFrame. This is valid only when mFrame is not
// nullptr.
uint32_t mOffsetInFrameContent = 0;
// Whether the caret should be put before or after the point. This is valid
// only when mFrame is not nullptr.
CaretAssociationHint mHint{0}; // Before
struct MOZ_STACK_CLASS CaretFrameData : public PrimaryFrameData {
// The frame which is found only from a DOM point. This frame becomes
// different from mFrame when the point is around end of a line or
// at a bidi text boundary.
nsIFrame* mUnadjustedFrame = nullptr;
enum class ForceEditableRegion : bool { No, Yes };
class SelectionMovementUtils final {
using PeekOffsetOptions = EnumSet<PeekOffsetOption>;
* Given a node and its child offset, return the nsIFrame and the offset into
* that frame.
* @param aNode input parameter for the node to look at
* TODO: Make this `const nsIContent*` for `ContentEventHandler`.
* @param aOffset offset into above node.
* @param aReturnOffset will contain offset into frame.
static nsIFrame* GetFrameForNodeOffset(nsIContent* aNode, uint32_t aOffset,
CaretAssociationHint aHint,
uint32_t* aReturnOffset = nullptr);
* GetPrevNextBidiLevels will return the frames and associated Bidi levels of
* the characters logically before and after a (collapsed) selection.
* @param aNode is the node containing the selection
* @param aContentOffset is the offset of the selection in the node
* @param aJumpLines
* If true, look across line boundaries.
* If false, behave as if there were base-level frames at line edges.
* @return A struct holding the before/after frame and the before/after
* level.
* At the beginning and end of each line there is assumed to be a frame with
* Bidi level equal to the paragraph embedding level.
* In these cases the before frame and after frame respectively will be
* nullptr.
static nsPrevNextBidiLevels GetPrevNextBidiLevels(nsIContent* aNode,
uint32_t aContentOffset,
CaretAssociationHint aHint,
bool aJumpLines);
* PeekOffsetForCaretMove() only peek offset for caret move from the specified
* point of the normal selection. I.e., won't change selection ranges nor
* bidi information.
static Result<PeekOffsetStruct, nsresult> PeekOffsetForCaretMove(
nsIContent* aContent, uint32_t aOffset, nsDirection aDirection,
CaretAssociationHint aHint, intl::BidiEmbeddingLevel aCaretBidiLevel,
const nsSelectionAmount aAmount, const nsPoint& aDesiredCaretPos,
PeekOffsetOptions aOptions);
* IsIntraLineCaretMove() is a helper method for PeekOffsetForCaretMove()
* and CreateRangeExtendedToSomwhereFromNormalSelection(). This returns
* whether aAmount is intra line move or is crossing hard line break.
* This returns error if aMount is not supported by the methods.
static Result<bool, nsresult> IsIntraLineCaretMove(
nsSelectionAmount aAmount) {
switch (aAmount) {
case eSelectCharacter:
case eSelectCluster:
case eSelectWord:
case eSelectWordNoSpace:
case eSelectBeginLine:
case eSelectEndLine:
return true;
case eSelectLine:
return false;
* Return a frame for considering caret geometry.
* @param aFrameSelection [optional] If this is specified and selection in
* aContent is not managed by the specified
* instance, return nullptr.
* @param aContentNode The content node where selection is collapsed.
* @param aOffset Collapsed position in aContentNode
* @param aFrameHint Caret association hint.
* @param aBidiLevel
* @param aForceEditableRegion Whether selection should be limited in
* editable region or not.
static CaretFrameData GetCaretFrameForNodeOffset(
const nsFrameSelection* aFrameSelection, nsIContent* aContentNode,
uint32_t aOffset, CaretAssociationHint aFrameHint,
intl::BidiEmbeddingLevel aBidiLevel,
ForceEditableRegion aForceEditableRegion);
static bool AdjustFrameForLineStart(nsIFrame*& aFrame,
uint32_t& aFrameOffset);
* Get primary frame and some other data for putting caret or extending
* selection at the point.
static PrimaryFrameData GetPrimaryFrameForCaret(
nsIContent* aContent, uint32_t aOffset, bool aVisual,
CaretAssociationHint aHint, intl::BidiEmbeddingLevel aCaretBidiLevel);
* GetFrameFromLevel will scan in a given direction
* until it finds a frame with a Bidi level less than or equal to a given
* level. It will return the last frame before this.
* @param aPresContext is the context to use
* @param aFrameIn is the frame to start from
* @param aDirection is the direction to scan
* @param aBidiLevel is the level to search for
static Result<nsIFrame*, nsresult> GetFrameFromLevel(
nsIFrame* aFrameIn, nsDirection aDirection,
intl::BidiEmbeddingLevel aBidiLevel);
// This is helper method for GetPrimaryFrameForCaret.
// If aVisual is true, this returns caret frame.
// If false, this returns primary frame.
static PrimaryFrameData GetPrimaryOrCaretFrameForNodeOffset(
nsIContent* aContent, uint32_t aOffset, bool aVisual,
CaretAssociationHint aHint, intl::BidiEmbeddingLevel aCaretBidiLevel);
} // namespace mozilla
#endif // #ifndef mozilla_SelectionMovementUtils_h