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gecko-dev/layout/generic/SelectionMovementUtils.cpp

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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 http://mozilla.org/MPL/2.0/. */
#include "ErrorList.h"
#include "SelectionMovementUtils.h"
#include "mozilla/CaretAssociationHint.h"
#include "mozilla/Maybe.h"
#include "mozilla/PresShell.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/Selection.h"
#include "mozilla/dom/ShadowRoot.h"
#include "mozilla/intl/BidiEmbeddingLevel.h"
#include "nsBidiPresUtils.h"
#include "nsBlockFrame.h"
#include "nsCaret.h"
#include "nsCOMPtr.h"
#include "nsFrameSelection.h"
#include "nsFrameTraversal.h"
#include "nsIContent.h"
#include "nsIFrame.h"
#include "nsIFrameInlines.h"
#include "nsLayoutUtils.h"
#include "nsPresContext.h"
#include "nsTextFrame.h"
namespace mozilla {
using namespace dom;
// FYI: This was done during a call of GetPrimaryFrameForCaretAtFocusNode.
// Therefore, this may not be intended by the original author.
// static
Result<PeekOffsetStruct, nsresult>
SelectionMovementUtils::PeekOffsetForCaretMove(
nsIContent* aContent, uint32_t aOffset, nsDirection aDirection,
CaretAssociationHint aHint, intl::BidiEmbeddingLevel aCaretBidiLevel,
const nsSelectionAmount aAmount, const nsPoint& aDesiredCaretPos,
PeekOffsetOptions aOptions) {
const PrimaryFrameData frameForFocus =
SelectionMovementUtils::GetPrimaryFrameForCaret(
aContent, aOffset, aOptions.contains(PeekOffsetOption::Visual), aHint,
aCaretBidiLevel);
if (!frameForFocus.mFrame) {
return Err(NS_ERROR_FAILURE);
}
aOptions += {PeekOffsetOption::JumpLines, PeekOffsetOption::IsKeyboardSelect};
PeekOffsetStruct pos(
aAmount, aDirection,
static_cast<int32_t>(frameForFocus.mOffsetInFrameContent),
aDesiredCaretPos, aOptions);
nsresult rv = frameForFocus.mFrame->PeekOffset(&pos);
if (NS_FAILED(rv)) {
return Err(rv);
}
return pos;
}
// static
nsPrevNextBidiLevels SelectionMovementUtils::GetPrevNextBidiLevels(
nsIContent* aNode, uint32_t aContentOffset, CaretAssociationHint aHint,
bool aJumpLines) {
// Get the level of the frames on each side
nsIFrame* currentFrame;
uint32_t currentOffset;
nsDirection direction;
nsPrevNextBidiLevels levels{};
levels.SetData(nullptr, nullptr, intl::BidiEmbeddingLevel::LTR(),
intl::BidiEmbeddingLevel::LTR());
currentFrame = SelectionMovementUtils::GetFrameForNodeOffset(
aNode, aContentOffset, aHint, &currentOffset);
if (!currentFrame) {
return levels;
}
auto [frameStart, frameEnd] = currentFrame->GetOffsets();
if (0 == frameStart && 0 == frameEnd) {
direction = eDirPrevious;
} else if (static_cast<uint32_t>(frameStart) == currentOffset) {
direction = eDirPrevious;
} else if (static_cast<uint32_t>(frameEnd) == currentOffset) {
direction = eDirNext;
} else {
// we are neither at the beginning nor at the end of the frame, so we have
// no worries
intl::BidiEmbeddingLevel currentLevel = currentFrame->GetEmbeddingLevel();
levels.SetData(currentFrame, currentFrame, currentLevel, currentLevel);
return levels;
}
PeekOffsetOptions peekOffsetOptions{PeekOffsetOption::StopAtScroller};
if (aJumpLines) {
peekOffsetOptions += PeekOffsetOption::JumpLines;
}
nsIFrame* newFrame =
currentFrame->GetFrameFromDirection(direction, peekOffsetOptions).mFrame;
FrameBidiData currentBidi = currentFrame->GetBidiData();
intl::BidiEmbeddingLevel currentLevel = currentBidi.embeddingLevel;
intl::BidiEmbeddingLevel newLevel =
newFrame ? newFrame->GetEmbeddingLevel() : currentBidi.baseLevel;
// If not jumping lines, disregard br frames, since they might be positioned
// incorrectly.
// XXX This could be removed once bug 339786 is fixed.
if (!aJumpLines) {
if (currentFrame->IsBrFrame()) {
currentFrame = nullptr;
currentLevel = currentBidi.baseLevel;
}
if (newFrame && newFrame->IsBrFrame()) {
newFrame = nullptr;
newLevel = currentBidi.baseLevel;
}
}
if (direction == eDirNext) {
levels.SetData(currentFrame, newFrame, currentLevel, newLevel);
} else {
levels.SetData(newFrame, currentFrame, newLevel, currentLevel);
}
return levels;
}
// static
Result<nsIFrame*, nsresult> SelectionMovementUtils::GetFrameFromLevel(
nsIFrame* aFrameIn, nsDirection aDirection,
intl::BidiEmbeddingLevel aBidiLevel) {
if (!aFrameIn) {
return Err(NS_ERROR_NULL_POINTER);
}
intl::BidiEmbeddingLevel foundLevel = intl::BidiEmbeddingLevel::LTR();
nsFrameIterator frameIterator(aFrameIn->PresContext(), aFrameIn,
nsFrameIterator::Type::Leaf,
false, // aVisual
false, // aLockInScrollView
false, // aFollowOOFs
false // aSkipPopupChecks
);
nsIFrame* foundFrame = aFrameIn;
nsIFrame* theFrame = nullptr;
do {
theFrame = foundFrame;
foundFrame = frameIterator.Traverse(aDirection == eDirNext);
if (!foundFrame) {
return Err(NS_ERROR_FAILURE);
}
foundLevel = foundFrame->GetEmbeddingLevel();
} while (foundLevel > aBidiLevel);
MOZ_ASSERT(theFrame);
return theFrame;
}
bool SelectionMovementUtils::AdjustFrameForLineStart(nsIFrame*& aFrame,
uint32_t& aFrameOffset) {
if (!aFrame->HasSignificantTerminalNewline()) {
return false;
}
auto [start, end] = aFrame->GetOffsets();
if (aFrameOffset != static_cast<uint32_t>(end)) {
return false;
}
nsIFrame* nextSibling = aFrame->GetNextSibling();
if (!nextSibling) {
return false;
}
aFrame = nextSibling;
std::tie(start, end) = aFrame->GetOffsets();
aFrameOffset = start;
return true;
}
static bool IsDisplayContents(const nsIContent* aContent) {
return aContent->IsElement() && aContent->AsElement()->IsDisplayContents();
}
// static
nsIFrame* SelectionMovementUtils::GetFrameForNodeOffset(
nsIContent* aNode, uint32_t aOffset, CaretAssociationHint aHint,
uint32_t* aReturnOffset /* = nullptr */) {
if (!aNode) {
return nullptr;
}
if (static_cast<int32_t>(aOffset) < 0) {
return nullptr;
}
if (!aNode->GetPrimaryFrame() && !IsDisplayContents(aNode)) {
return nullptr;
}
nsIFrame* returnFrame = nullptr;
nsCOMPtr<nsIContent> theNode;
uint32_t offsetInFrameContent;
while (true) {
offsetInFrameContent = aOffset;
theNode = aNode;
if (aNode->IsElement()) {
uint32_t childIndex = 0;
uint32_t numChildren = theNode->GetChildCount();
if (aHint == CaretAssociationHint::Before) {
if (aOffset > 0) {
childIndex = aOffset - 1;
} else {
childIndex = aOffset;
}
} else {
MOZ_ASSERT(aHint == CaretAssociationHint::After);
if (aOffset >= numChildren) {
if (numChildren > 0) {
childIndex = numChildren - 1;
} else {
childIndex = 0;
}
} else {
childIndex = aOffset;
}
}
if (childIndex > 0 || numChildren > 0) {
nsCOMPtr<nsIContent> childNode =
theNode->GetChildAt_Deprecated(childIndex);
if (!childNode) {
break;
}
theNode = childNode;
}
// Now that we have the child node, check if it too
// can contain children. If so, descend into child.
if (theNode->IsElement() && theNode->GetChildCount() &&
!theNode->HasIndependentSelection()) {
aNode = theNode;
aOffset = aOffset > childIndex ? theNode->GetChildCount() : 0;
continue;
}
// Check to see if theNode is a text node. If it is, translate
// aOffset into an offset into the text node.
RefPtr<Text> textNode = theNode->GetAsText();
if (textNode) {
if (theNode->GetPrimaryFrame()) {
if (aOffset > childIndex) {
uint32_t textLength = textNode->Length();
offsetInFrameContent = textLength;
} else {
offsetInFrameContent = 0;
}
} else {
uint32_t numChildren = aNode->GetChildCount();
uint32_t newChildIndex = aHint == CaretAssociationHint::Before
? childIndex - 1
: childIndex + 1;
if (newChildIndex < numChildren) {
nsCOMPtr<nsIContent> newChildNode =
aNode->GetChildAt_Deprecated(newChildIndex);
if (!newChildNode) {
return nullptr;
}
aNode = newChildNode;
aOffset = aHint == CaretAssociationHint::Before
? aNode->GetChildCount()
: 0;
continue;
} // newChildIndex is illegal which means we're at first or last
// child. Just use original node to get the frame.
theNode = aNode;
}
}
}
// If the node is a ShadowRoot, the frame needs to be adjusted,
// because a ShadowRoot does not get a frame. Its children are rendered
// as children of the host.
if (ShadowRoot* shadow = ShadowRoot::FromNode(theNode)) {
theNode = shadow->GetHost();
}
returnFrame = theNode->GetPrimaryFrame();
if (!returnFrame) {
if (aHint == CaretAssociationHint::Before) {
if (aOffset > 0) {
--aOffset;
continue;
}
break;
}
if (aOffset < theNode->GetChildCount()) {
++aOffset;
continue;
}
break;
}
break;
} // end while
if (!returnFrame) {
return nullptr;
}
// If we ended up here and were asked to position the caret after a visible
// break, let's return the frame on the next line instead if it exists.
if (aOffset > 0 && (uint32_t)aOffset >= aNode->Length() &&
theNode == aNode->GetLastChild()) {
nsIFrame* newFrame;
nsLayoutUtils::IsInvisibleBreak(theNode, &newFrame);
if (newFrame) {
returnFrame = newFrame;
offsetInFrameContent = 0;
}
}
// find the child frame containing the offset we want
int32_t unused = 0;
returnFrame->GetChildFrameContainingOffset(
static_cast<int32_t>(offsetInFrameContent),
aHint == CaretAssociationHint::After, &unused, &returnFrame);
if (aReturnOffset) {
*aReturnOffset = offsetInFrameContent;
}
return returnFrame;
}
/**
* Find the first frame in an in-order traversal of the frame subtree rooted
* at aFrame which is either a text frame logically at the end of a line,
* or which is aStopAtFrame. Return null if no such frame is found. We don't
* descend into the children of non-eLineParticipant frames.
*/
static nsIFrame* CheckForTrailingTextFrameRecursive(nsIFrame* aFrame,
nsIFrame* aStopAtFrame) {
if (aFrame == aStopAtFrame ||
((aFrame->IsTextFrame() &&
(static_cast<nsTextFrame*>(aFrame))->IsAtEndOfLine()))) {
return aFrame;
}
if (!aFrame->IsLineParticipant()) {
return nullptr;
}
for (nsIFrame* f : aFrame->PrincipalChildList()) {
if (nsIFrame* r = CheckForTrailingTextFrameRecursive(f, aStopAtFrame)) {
return r;
}
}
return nullptr;
}
static nsLineBox* FindContainingLine(nsIFrame* aFrame) {
while (aFrame && aFrame->IsLineParticipant()) {
nsIFrame* parent = aFrame->GetParent();
nsBlockFrame* blockParent = do_QueryFrame(parent);
if (blockParent) {
bool isValid;
nsBlockInFlowLineIterator iter(blockParent, aFrame, &isValid);
return isValid ? iter.GetLine().get() : nullptr;
}
aFrame = parent;
}
return nullptr;
}
static void AdjustCaretFrameForLineEnd(nsIFrame** aFrame, uint32_t* aOffset,
bool aEditableOnly) {
nsLineBox* line = FindContainingLine(*aFrame);
if (!line) {
return;
}
uint32_t count = line->GetChildCount();
for (nsIFrame* f = line->mFirstChild; count > 0;
--count, f = f->GetNextSibling()) {
nsIFrame* r = CheckForTrailingTextFrameRecursive(f, *aFrame);
if (r == *aFrame) {
return;
}
if (!r) {
continue;
}
// If found text frame is non-editable but the start frame content is
// editable, we don't want to put caret into the non-editable text node.
// We should return the given frame as-is in this case.
if (aEditableOnly && !r->GetContent()->IsEditable()) {
return;
}
// We found our frame, but we may not be able to properly paint the caret
// if -moz-user-modify differs from our actual frame.
MOZ_ASSERT(r->IsTextFrame(), "Expected text frame");
*aFrame = r;
*aOffset = (static_cast<nsTextFrame*>(r))->GetContentEnd();
return;
// FYI: Setting the caret association hint was done during a call of
// GetPrimaryFrameForCaretAtFocusNode. Therefore, this may not be intended
// by the original author.
}
}
CaretFrameData SelectionMovementUtils::GetCaretFrameForNodeOffset(
const nsFrameSelection* aFrameSelection, nsIContent* aContentNode,
uint32_t aOffset, CaretAssociationHint aFrameHint,
intl::BidiEmbeddingLevel aBidiLevel,
ForceEditableRegion aForceEditableRegion) {
if (!aContentNode || !aContentNode->IsInComposedDoc()) {
return {};
}
CaretFrameData result;
result.mHint = aFrameHint;
if (aFrameSelection) {
PresShell* presShell = aFrameSelection->GetPresShell();
if (!presShell) {
return {};
}
if (!aContentNode || !aContentNode->IsInComposedDoc() ||
presShell->GetDocument() != aContentNode->GetComposedDoc()) {
return {};
}
result.mHint = aFrameSelection->GetHint();
}
MOZ_ASSERT_IF(aForceEditableRegion == ForceEditableRegion::Yes,
aContentNode->IsEditable());
result.mFrame = result.mUnadjustedFrame =
SelectionMovementUtils::GetFrameForNodeOffset(
aContentNode, aOffset, aFrameHint, &result.mOffsetInFrameContent);
if (!result.mFrame) {
return {};
}
if (SelectionMovementUtils::AdjustFrameForLineStart(
result.mFrame, result.mOffsetInFrameContent)) {
result.mHint = CaretAssociationHint::After;
} else {
// if the frame is after a text frame that's logically at the end of the
// line (e.g. if the frame is a <br> frame), then put the caret at the end
// of that text frame instead. This way, the caret will be positioned as if
// trailing whitespace was not trimmed.
AdjustCaretFrameForLineEnd(
&result.mFrame, &result.mOffsetInFrameContent,
aForceEditableRegion == ForceEditableRegion::Yes);
}
// Mamdouh : modification of the caret to work at rtl and ltr with Bidi
//
// Direction Style from visibility->mDirection
// ------------------
if (!result.mFrame->PresContext()->BidiEnabled()) {
return result;
}
// If there has been a reflow, take the caret Bidi level to be the level of
// the current frame
if (aBidiLevel & BIDI_LEVEL_UNDEFINED) {
aBidiLevel = result.mFrame->GetEmbeddingLevel();
}
nsIFrame* frameBefore;
nsIFrame* frameAfter;
intl::BidiEmbeddingLevel
levelBefore; // Bidi level of the character before the caret
intl::BidiEmbeddingLevel
levelAfter; // Bidi level of the character after the caret
auto [start, end] = result.mFrame->GetOffsets();
if (start == 0 || end == 0 ||
static_cast<uint32_t>(start) == result.mOffsetInFrameContent ||
static_cast<uint32_t>(end) == result.mOffsetInFrameContent) {
nsPrevNextBidiLevels levels = SelectionMovementUtils::GetPrevNextBidiLevels(
aContentNode, aOffset, result.mHint, false);
/* Boundary condition, we need to know the Bidi levels of the characters
* before and after the caret */
if (levels.mFrameBefore || levels.mFrameAfter) {
frameBefore = levels.mFrameBefore;
frameAfter = levels.mFrameAfter;
levelBefore = levels.mLevelBefore;
levelAfter = levels.mLevelAfter;
if ((levelBefore != levelAfter) || (aBidiLevel != levelBefore)) {
aBidiLevel =
std::max(aBidiLevel, std::min(levelBefore, levelAfter)); // rule c3
aBidiLevel =
std::min(aBidiLevel, std::max(levelBefore, levelAfter)); // rule c4
if (aBidiLevel == levelBefore || // rule c1
(aBidiLevel > levelBefore && aBidiLevel < levelAfter &&
aBidiLevel.IsSameDirection(levelBefore)) || // rule c5
(aBidiLevel < levelBefore && aBidiLevel > levelAfter &&
aBidiLevel.IsSameDirection(levelBefore))) // rule c9
{
if (result.mFrame != frameBefore) {
if (frameBefore) { // if there is a frameBefore, move into it
result.mFrame = frameBefore;
std::tie(start, end) = result.mFrame->GetOffsets();
result.mOffsetInFrameContent = end;
} else {
// if there is no frameBefore, we must be at the beginning of
// the line so we stay with the current frame. Exception: when
// the first frame on the line has a different Bidi level from
// the paragraph level, there is no real frame for the caret to
// be in. We have to find the visually first frame on the line.
intl::BidiEmbeddingLevel baseLevel = frameAfter->GetBaseLevel();
if (baseLevel != levelAfter) {
PeekOffsetStruct pos(eSelectBeginLine, eDirPrevious, 0,
nsPoint(0, 0),
{PeekOffsetOption::StopAtScroller,
PeekOffsetOption::Visual});
if (NS_SUCCEEDED(frameAfter->PeekOffset(&pos))) {
result.mFrame = pos.mResultFrame;
result.mOffsetInFrameContent = pos.mContentOffset;
}
}
}
}
} else if (aBidiLevel == levelAfter || // rule c2
(aBidiLevel > levelBefore && aBidiLevel < levelAfter &&
aBidiLevel.IsSameDirection(levelAfter)) || // rule c6
(aBidiLevel < levelBefore && aBidiLevel > levelAfter &&
aBidiLevel.IsSameDirection(levelAfter))) // rule c10
{
if (result.mFrame != frameAfter) {
if (frameAfter) {
// if there is a frameAfter, move into it
result.mFrame = frameAfter;
std::tie(start, end) = result.mFrame->GetOffsets();
result.mOffsetInFrameContent = start;
} else {
// if there is no frameAfter, we must be at the end of the line
// so we stay with the current frame.
// Exception: when the last frame on the line has a different
// Bidi level from the paragraph level, there is no real frame
// for the caret to be in. We have to find the visually last
// frame on the line.
intl::BidiEmbeddingLevel baseLevel = frameBefore->GetBaseLevel();
if (baseLevel != levelBefore) {
PeekOffsetStruct pos(eSelectEndLine, eDirNext, 0, nsPoint(0, 0),
{PeekOffsetOption::StopAtScroller,
PeekOffsetOption::Visual});
if (NS_SUCCEEDED(frameBefore->PeekOffset(&pos))) {
result.mFrame = pos.mResultFrame;
result.mOffsetInFrameContent = pos.mContentOffset;
}
}
}
}
} else if (aBidiLevel > levelBefore &&
aBidiLevel < levelAfter && // rule c7/8
// before and after have the same parity
levelBefore.IsSameDirection(levelAfter) &&
// caret has different parity
!aBidiLevel.IsSameDirection(levelAfter)) {
MOZ_ASSERT_IF(aFrameSelection && aFrameSelection->GetPresShell(),
aFrameSelection->GetPresShell()->GetPresContext() ==
frameAfter->PresContext());
Result<nsIFrame*, nsresult> frameOrError =
SelectionMovementUtils::GetFrameFromLevel(frameAfter, eDirNext,
aBidiLevel);
if (MOZ_LIKELY(frameOrError.isOk())) {
result.mFrame = frameOrError.unwrap();
std::tie(start, end) = result.mFrame->GetOffsets();
levelAfter = result.mFrame->GetEmbeddingLevel();
if (aBidiLevel.IsRTL()) {
// c8: caret to the right of the rightmost character
result.mOffsetInFrameContent = levelAfter.IsRTL() ? start : end;
} else {
// c7: caret to the left of the leftmost character
result.mOffsetInFrameContent = levelAfter.IsRTL() ? end : start;
}
}
} else if (aBidiLevel < levelBefore &&
aBidiLevel > levelAfter && // rule c11/12
// before and after have the same parity
levelBefore.IsSameDirection(levelAfter) &&
// caret has different parity
!aBidiLevel.IsSameDirection(levelAfter)) {
MOZ_ASSERT_IF(aFrameSelection && aFrameSelection->GetPresShell(),
aFrameSelection->GetPresShell()->GetPresContext() ==
frameBefore->PresContext());
Result<nsIFrame*, nsresult> frameOrError =
SelectionMovementUtils::GetFrameFromLevel(
frameBefore, eDirPrevious, aBidiLevel);
if (MOZ_LIKELY(frameOrError.isOk())) {
result.mFrame = frameOrError.unwrap();
std::tie(start, end) = result.mFrame->GetOffsets();
levelBefore = result.mFrame->GetEmbeddingLevel();
if (aBidiLevel.IsRTL()) {
// c12: caret to the left of the leftmost character
result.mOffsetInFrameContent = levelBefore.IsRTL() ? end : start;
} else {
// c11: caret to the right of the rightmost character
result.mOffsetInFrameContent = levelBefore.IsRTL() ? start : end;
}
}
}
}
}
}
return result;
}
// static
PrimaryFrameData SelectionMovementUtils::GetPrimaryFrameForCaret(
nsIContent* aContent, uint32_t aOffset, bool aVisual,
CaretAssociationHint aHint, intl::BidiEmbeddingLevel aCaretBidiLevel) {
MOZ_ASSERT(aContent);
{
const PrimaryFrameData result =
SelectionMovementUtils::GetPrimaryOrCaretFrameForNodeOffset(
aContent, aOffset, aVisual, aHint, aCaretBidiLevel);
if (result.mFrame) {
return result;
}
}
// If aContent is whitespace only, we promote focus node to parent because
// whitespace only node might have no frame.
if (!aContent->TextIsOnlyWhitespace()) {
return {};
}
nsIContent* parent = aContent->GetParent();
if (NS_WARN_IF(!parent)) {
return {};
}
const Maybe<uint32_t> offset = parent->ComputeIndexOf(aContent);
if (NS_WARN_IF(offset.isNothing())) {
return {};
}
return SelectionMovementUtils::GetPrimaryOrCaretFrameForNodeOffset(
parent, *offset, aVisual, aHint, aCaretBidiLevel);
}
// static
PrimaryFrameData SelectionMovementUtils::GetPrimaryOrCaretFrameForNodeOffset(
nsIContent* aContent, uint32_t aOffset, bool aVisual,
CaretAssociationHint aHint, intl::BidiEmbeddingLevel aCaretBidiLevel) {
if (aVisual) {
const CaretFrameData result =
SelectionMovementUtils::GetCaretFrameForNodeOffset(
nullptr, aContent, aOffset, aHint, aCaretBidiLevel,
aContent && aContent->IsEditable() ? ForceEditableRegion::Yes
: ForceEditableRegion::No);
return {result.mFrame, result.mOffsetInFrameContent, result.mHint};
}
uint32_t offset = 0;
nsIFrame* theFrame = SelectionMovementUtils::GetFrameForNodeOffset(
aContent, aOffset, aHint, &offset);
return {theFrame, offset, aHint};
}
} // namespace mozilla
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