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// Copyright (c) 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "core/editing/commands/InsertIncrementalTextCommand.h"
#include "core/dom/Document.h"
#include "core/dom/Element.h"
#include "core/dom/Text.h"
#include "core/editing/EditingUtilities.h"
#include "core/editing/Editor.h"
#include "core/editing/PlainTextRange.h"
#include "core/editing/VisibleUnits.h"
#include "core/editing/iterators/CharacterIterator.h"
#include "core/html/HTMLSpanElement.h"
namespace blink {
namespace {
size_t computeCommonPrefixLength(const String& str1, const String& str2) {
const size_t maxCommonPrefixLength = std::min(str1.length(), str2.length());
for (size_t index = 0; index < maxCommonPrefixLength; ++index) {
if (str1[index] != str2[index])
return index;
}
return maxCommonPrefixLength;
}
size_t computeCommonSuffixLength(const String& str1, const String& str2) {
const size_t length1 = str1.length();
const size_t length2 = str2.length();
const size_t maxCommonSuffixLength = std::min(length1, length2);
for (size_t index = 0; index < maxCommonSuffixLength; ++index) {
if (str1[length1 - index - 1] != str2[length2 - index - 1])
return index;
}
return maxCommonSuffixLength;
}
// If current position is at grapheme boundary, return 0; otherwise, return the
// distance to its nearest left grapheme boundary.
size_t computeDistanceToLeftGraphemeBoundary(const Position& position) {
const Position& adjustedPosition = previousPositionOf(
nextPositionOf(position, PositionMoveType::GraphemeCluster),
PositionMoveType::GraphemeCluster);
DCHECK_EQ(position.anchorNode(), adjustedPosition.anchorNode());
DCHECK_GE(position.computeOffsetInContainerNode(),
adjustedPosition.computeOffsetInContainerNode());
return static_cast<size_t>(position.computeOffsetInContainerNode() -
adjustedPosition.computeOffsetInContainerNode());
}
size_t computeCommonGraphemeClusterPrefixLength(
const int selectionStart,
const String& oldText,
const String& newText,
const Element* rootEditableElement) {
const size_t commonPrefixLength = computeCommonPrefixLength(oldText, newText);
// For grapheme cluster, we should adjust it for grapheme boundary.
const EphemeralRange& range =
PlainTextRange(0, selectionStart + commonPrefixLength)
.createRange(*rootEditableElement);
if (range.isNull())
return 0;
const Position& position = range.endPosition();
const size_t diff = computeDistanceToLeftGraphemeBoundary(position);
DCHECK_GE(commonPrefixLength, diff);
return commonPrefixLength - diff;
}
// If current position is at grapheme boundary, return 0; otherwise, return the
// distance to its nearest right grapheme boundary.
size_t computeDistanceToRightGraphemeBoundary(const Position& position) {
const Position& adjustedPosition = nextPositionOf(
previousPositionOf(position, PositionMoveType::GraphemeCluster),
PositionMoveType::GraphemeCluster);
DCHECK_EQ(position.anchorNode(), adjustedPosition.anchorNode());
DCHECK_GE(adjustedPosition.computeOffsetInContainerNode(),
position.computeOffsetInContainerNode());
return static_cast<size_t>(adjustedPosition.computeOffsetInContainerNode() -
position.computeOffsetInContainerNode());
}
size_t computeCommonGraphemeClusterSuffixLength(
const int selectionStart,
const String& oldText,
const String& newText,
const Element* rootEditableElement) {
const size_t commonSuffixLength = computeCommonSuffixLength(oldText, newText);
// For grapheme cluster, we should adjust it for grapheme boundary.
const EphemeralRange& range =
PlainTextRange(0, selectionStart + oldText.length() - commonSuffixLength)
.createRange(*rootEditableElement);
if (range.isNull())
return 0;
const Position& position = range.endPosition();
const size_t diff = computeDistanceToRightGraphemeBoundary(position);
DCHECK_GE(commonSuffixLength, diff);
return commonSuffixLength - diff;
}
const String computeTextForInsertion(const String& newText,
const size_t commonPrefixLength,
const size_t commonSuffixLength) {
return newText.substring(
commonPrefixLength,
newText.length() - commonPrefixLength - commonSuffixLength);
}
VisibleSelection computeSelectionForInsertion(
const EphemeralRange& selectionRange,
const int offset,
const int length,
const bool isDirectional) {
CharacterIterator charIt(selectionRange);
const EphemeralRange& rangeForInsertion =
charIt.calculateCharacterSubrange(offset, length);
const VisibleSelection& selection =
createVisibleSelection(SelectionInDOMTree::Builder()
.setBaseAndExtent(rangeForInsertion)
.setIsDirectional(isDirectional)
.build());
return selection;
}
} // anonymous namespace
InsertIncrementalTextCommand* InsertIncrementalTextCommand::create(
Document& document,
const String& text,
bool selectInsertedText,
RebalanceType rebalanceType) {
return new InsertIncrementalTextCommand(document, text, selectInsertedText,
rebalanceType);
}
InsertIncrementalTextCommand::InsertIncrementalTextCommand(
Document& document,
const String& text,
bool selectInsertedText,
RebalanceType rebalanceType)
: InsertTextCommand(document, text, selectInsertedText, rebalanceType) {}
void InsertIncrementalTextCommand::doApply(EditingState* editingState) {
const Element* element = endingSelection().rootEditableElement();
DCHECK(element);
const EphemeralRange selectionRange(endingSelection().start(),
endingSelection().end());
const String oldText = plainText(selectionRange);
const String& newText = m_text;
const int selectionStart =
endingSelection().start().computeOffsetInContainerNode();
const size_t newTextLength = newText.length();
const size_t oldTextLength = oldText.length();
const size_t commonPrefixLength = computeCommonGraphemeClusterPrefixLength(
selectionStart, oldText, newText, element);
// We should ignore common prefix when finding common suffix.
const size_t commonSuffixLength = computeCommonGraphemeClusterSuffixLength(
selectionStart, oldText.right(oldTextLength - commonPrefixLength),
newText.right(newTextLength - commonPrefixLength), element);
DCHECK_GE(oldTextLength, commonPrefixLength + commonSuffixLength);
m_text =
computeTextForInsertion(m_text, commonPrefixLength, commonSuffixLength);
const int offset = static_cast<int>(commonPrefixLength);
const int length =
static_cast<int>(oldTextLength - commonPrefixLength - commonSuffixLength);
const VisibleSelection& selectionForInsertion = computeSelectionForInsertion(
selectionRange, offset, length, endingSelection().isDirectional());
setEndingSelectionWithoutValidation(selectionForInsertion.start(),
selectionForInsertion.end());
InsertTextCommand::doApply(editingState);
}
} // namespace blink
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