From 8915f5d40d1040f8408a59dfb552aaee73705a4e Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 17 Oct 2023 12:01:50 +0400
Subject: [PATCH] Fix modifications tracking with skip block.

---
 ui/text/text.cpp        | 57 ++++++++++++++++++++++++++++++++++++++---
 ui/text/text.h          |  2 ++
 ui/text/text_parser.cpp | 35 +++++--------------------
 3 files changed, 63 insertions(+), 31 deletions(-)

diff --git a/ui/text/text.cpp b/ui/text/text.cpp
index a4ba32e..af66be4 100644
--- a/ui/text/text.cpp
+++ b/ui/text/text.cpp
@@ -673,9 +673,12 @@ bool String::updateSkipBlock(int width, int height) {
 		if (block->f_width().toInt() == width && block->height() == height) {
 			return false;
 		}
-		_text.resize(block->position());
+		const auto size = block->position();
+		_text.resize(size);
 		_blocks.pop_back();
+		removeModificationsAfter(size);
 	} else if (_endsWithQuote) {
+		insertModifications(_text.size(), 1);
 		_text.push_back(QChar::LineFeed);
 		_blocks.push_back(Block::Newline(
 			_st->font,
@@ -687,6 +690,7 @@ bool String::updateSkipBlock(int width, int height) {
 			0));
 		_skipBlockAddedNewline = true;
 	}
+	insertModifications(_text.size(), 1);
 	_text.push_back('_');
 	_blocks.push_back(Block::Skip(
 		_st->font,
@@ -704,18 +708,65 @@ bool String::removeSkipBlock() {
 	if (_blocks.empty() || _blocks.back()->type() != TextBlockType::Skip) {
 		return false;
 	} else if (_skipBlockAddedNewline) {
-		_text.resize(_blocks.back()->position() - 1);
+		const auto size = _blocks.back()->position() - 1;
+		_text.resize(size);
 		_blocks.pop_back();
 		_blocks.pop_back();
 		_skipBlockAddedNewline = false;
+		removeModificationsAfter(size);
 	} else {
-		_text.resize(_blocks.back()->position());
+		const auto size = _blocks.back()->position();
+		_text.resize(size);
 		_blocks.pop_back();
+		removeModificationsAfter(size);
 	}
 	recountNaturalSize(false);
 	return true;
 }
 
+void String::insertModifications(int position, int delta) {
+	auto &modifications = ensureExtended()->modifications;
+	auto i = end(modifications);
+	while (i != begin(modifications) && (--i)->position >= position) {
+		if (i->position < position) {
+			break;
+		} else if (delta > 0) {
+			++i->position;
+		} else if (i->position == position) {
+			break;
+		}
+	}
+	if (i != end(modifications) && i->position == position) {
+		++i->skipped;
+	} else {
+		modifications.insert(i, {
+			.position = position,
+			.skipped = uint16(delta < 0 ? (-delta) : 0),
+			.added = (delta > 0),
+		});
+	}
+}
+
+void String::removeModificationsAfter(int size) {
+	if (!_extended) {
+		return;
+	}
+	auto &modifications = _extended->modifications;
+	for (auto i = end(modifications); i != begin(modifications);) {
+		--i;
+		if (i->position > size) {
+			i = modifications.erase(i);
+		} else if (i->position == size) {
+			i->added = false;
+			if (!i->skipped) {
+				i = modifications.erase(i);
+			}
+		} else {
+			break;
+		}
+	}
+}
+
 int String::countWidth(int width, bool breakEverywhere) const {
 	if (QFixed(width) >= _maxWidth) {
 		return _maxWidth;
diff --git a/ui/text/text.h b/ui/text/text.h
index 4ee53ec..bb412a1 100644
--- a/ui/text/text.h
+++ b/ui/text/text.h
@@ -407,6 +407,8 @@ private:
 		bool breakEverywhere,
 		Callback callback) const;
 
+	void insertModifications(int position, int delta);
+	void removeModificationsAfter(int size);
 	void recountNaturalSize(
 		bool initial,
 		Qt::LayoutDirection optionsDir = Qt::LayoutDirectionAuto);
diff --git a/ui/text/text_parser.cpp b/ui/text/text_parser.cpp
index 393c59e..27de57a 100644
--- a/ui/text/text_parser.cpp
+++ b/ui/text/text_parser.cpp
@@ -183,7 +183,7 @@ void Parser::createBlock(int32 skipBack) {
 	if (_newlineAwaited) {
 		_newlineAwaited = false;
 		if (!newline) {
-			updateModifications(_blockStart, 1);
+			_t->insertModifications(_blockStart, 1);
 			_t->_text.insert(_blockStart, QChar::LineFeed);
 			createBlock(skipBack - length);
 		}
@@ -226,7 +226,7 @@ void Parser::createBlock(int32 skipBack) {
 
 void Parser::createNewlineBlock(bool fromOriginalText) {
 	if (!fromOriginalText) {
-		updateModifications(_t->_text.size(), 1);
+		_t->insertModifications(_t->_text.size(), 1);
 	}
 	_t->_text.push_back(QChar::LineFeed);
 	_allowDiacritic = false;
@@ -523,7 +523,9 @@ void Parser::parseCurrentChar() {
 	}
 
 	if (skip) {
-		updateModifications(_t->_text.size(), -1);
+		if (_ptr < _end) {
+			_t->insertModifications(_t->_text.size(), -1);
+		}
 		_ch = 0;
 		_allowDiacritic = false;
 	} else {
@@ -572,7 +574,7 @@ void Parser::parseEmojiFromCurrent() {
 		Assert(!_t->_text.isEmpty());
 		const auto last = _t->_text[_t->_text.size() - 1];
 		if (last.unicode() != Emoji::kPostfix) {
-			updateModifications(_t->_text.size(), 1);
+			_t->insertModifications(_t->_text.size(), 1);
 			_t->_text.push_back(QChar(Emoji::kPostfix));
 			++len;
 		}
@@ -602,29 +604,6 @@ bool Parser::isLinkEntity(const EntityInText &entity) const {
 	return ranges::find(urls, type) != std::end(urls);
 }
 
-void Parser::updateModifications(int index, int delta) {
-	auto &modifications = _t->ensureExtended()->modifications;
-	auto i = end(modifications);
-	while (i != begin(modifications) && (--i)->position >= index) {
-		if (i->position < index) {
-			break;
-		} else if (delta > 0) {
-			++i->position;
-		} else if (i->position == index) {
-			break;
-		}
-	}
-	if (i != end(modifications) && i->position == index) {
-		++i->skipped;
-	} else {
-		modifications.insert(i, {
-			.position = index,
-			.skipped = uint16(delta < 0 ? 1 : 0),
-			.added = (delta > 0),
-		});
-	}
-}
-
 void Parser::parse(const TextParseOptions &options) {
 	skipBadEntities();
 	trimSourceRange();
@@ -636,7 +615,7 @@ void Parser::parse(const TextParseOptions &options) {
 	_t->_text.reserve(_end - _ptr);
 
 	if (_ptr > _start) {
-		updateModifications(0, -(_ptr - _start));
+		_t->insertModifications(0, -(_ptr - _start));
 	}
 
 	for (; _ptr <= _end; ++_ptr) {