Moved management of selecting scroll to separated class in td_ui.

Telegram/SourceFiles/chat_helpers/emoji_interactions.cpp

@@ -490,7 +490,7 @@ EmojiInteractionsBunch EmojiInteractions::Parse(const QByteArray &json) {
 		return {};
 	}
 	auto result = EmojiInteractionsBunch();
-	for (const auto &interaction : actions) {
+	for (const auto interaction : actions) {
 		const auto object = interaction.toObject();
 		const auto index = object.value("i").toInt();
 		if (index < 0 || index > 10) {

Telegram/SourceFiles/history/history_inner_widget.cpp

@@ -252,6 +252,11 @@ HistoryInner::HistoryInner(
 	) | rpl::start_with_next([=](bool wide) {
 		_isChatWide = wide;
 	}, lifetime());
+
+	_selectScroll.scrolls(
+	) | rpl::start_with_next([=](int d) {
+		_scroll->scrollToY(_scroll->scrollTop() + d);
+	}, _scroll->lifetime());
 }
 
 Main::Session &HistoryInner::session() const {
@@ -1226,7 +1231,7 @@ void HistoryInner::mouseActionCancel() {
 	_dragStartPosition = QPoint(0, 0);
 	_dragSelFrom = _dragSelTo = nullptr;
 	_wasSelectedText = false;
-	_widget->noSelectingScroll();
+	_selectScroll.cancel();
 }
 
 std::unique_ptr<QMimeData> HistoryInner::prepareDrag() {
@@ -1281,7 +1286,7 @@ std::unique_ptr<QMimeData> HistoryInner::prepareDrag() {
 	}();
 	if (auto mimeData = TextUtilities::MimeDataFromText(selectedText)) {
 		updateDragSelection(nullptr, nullptr, false);
-		_widget->noSelectingScroll();
+		_selectScroll.cancel();
 
 		if (!urls.isEmpty()) mimeData->setUrls(urls);
 		if (uponSelected && !_controller->adaptive().isOneColumn()) {
@@ -1474,7 +1479,7 @@ void HistoryInner::mouseActionFinish(
 	_mouseAction = MouseAction::None;
 	_mouseActionItem = nullptr;
 	_mouseSelectType = TextSelectType::Letters;
-	_widget->noSelectingScroll();
+	_selectScroll.cancel();
 	_widget->updateTopBarSelection();
 
 	if (QGuiApplication::clipboard()->supportsSelection()
@@ -3064,10 +3069,13 @@ void HistoryInner::mouseActionUpdate() {
 	}
 
 	if (_mouseAction == MouseAction::Selecting) {
-		_widget->checkSelectingScroll(mousePos);
+		_selectScroll.checkDeltaScroll(
+			mousePos,
+			_scroll->scrollTop(),
+			_scroll->scrollTop() + _scroll->height());
 	} else {
 		updateDragSelection(nullptr, nullptr, false);
-		_widget->noSelectingScroll();
+		_selectScroll.cancel();
 	}
 
 	if (_mouseAction == MouseAction::None && (lnkChanged || cur != _cursor)) {

Telegram/SourceFiles/history/history_inner_widget.h

@@ -7,9 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "base/timer.h"
 #include "ui/rp_widget.h"
 #include "ui/effects/animations.h"
+#include "ui/chat/select_scroll_manager.h" // Has base/timer.h.
 #include "ui/widgets/tooltip.h"
 #include "ui/widgets/scroll_area.h"
 #include "history/view/history_view_top_bar_widget.h"
@@ -413,6 +413,8 @@ private:
 	QPoint _touchStart, _touchPrevPos, _touchPos;
 	base::Timer _touchSelectTimer;
 
+	Ui::SelectScrollManager _selectScroll;
+
 	Ui::TouchScrollState _touchScrollState = Ui::TouchScrollState::Manual;
 	bool _touchPrevPosValid = false;
 	bool _touchWaitingAcceleration = false;

Telegram/SourceFiles/history/history_widget.cpp

@@ -247,7 +247,6 @@ HistoryWidget::HistoryWidget(
 	controller,
 	this)))
 , _membersDropdownShowTimer([=] { showMembersDropdown(); })
-, _scrollTimer([=] { scrollByTimer(); })
 , _saveDraftTimer([=] { saveDraft(); })
 , _saveCloudDraftTimer([=] { saveCloudDraft(); })
 , _topShadow(this) {
@@ -2079,7 +2078,6 @@ void HistoryWidget::showHistory(
 		}
 	}
 
-	noSelectingScroll();
 	_nonEmptySelection = false;
 	_itemRevealPending.clear();
 	_itemRevealAnimations.clear();
@@ -7313,32 +7311,6 @@ QPoint HistoryWidget::clampMousePosition(QPoint point) {
 	return point;
 }
 
-void HistoryWidget::scrollByTimer() {
-	const auto d = (_scrollDelta > 0)
-		? qMin(_scrollDelta * 3 / 20 + 1, int32(Ui::kMaxScrollSpeed))
-		: qMax(_scrollDelta * 3 / 20 - 1, -int32(Ui::kMaxScrollSpeed));
-	_scroll->scrollToY(_scroll->scrollTop() + d);
-}
-
-void HistoryWidget::checkSelectingScroll(QPoint point) {
-	if (point.y() < _scroll->scrollTop()) {
-		_scrollDelta = point.y() - _scroll->scrollTop();
-	} else if (point.y() >= _scroll->scrollTop() + _scroll->height()) {
-		_scrollDelta = point.y() - _scroll->scrollTop() - _scroll->height() + 1;
-	} else {
-		_scrollDelta = 0;
-	}
-	if (_scrollDelta) {
-		_scrollTimer.callEach(15);
-	} else {
-		_scrollTimer.cancel();
-	}
-}
-
-void HistoryWidget::noSelectingScroll() {
-	_scrollTimer.cancel();
-}
-
 bool HistoryWidget::touchScroll(const QPoint &delta) {
 	int32 scTop = _scroll->scrollTop(), scMax = _scroll->scrollTopMax();
 	const auto scNew = std::clamp(scTop - delta.y(), 0, scMax);

Telegram/SourceFiles/history/history_widget.h

@@ -183,9 +183,6 @@ public:
 
 	QPoint clampMousePosition(QPoint point);
 
-	void checkSelectingScroll(QPoint point);
-	void noSelectingScroll();
-
 	bool touchScroll(const QPoint &delta);
 
 	void enqueueMessageHighlight(not_null<HistoryView::Element*> view);
@@ -365,7 +362,6 @@ private:
 	void preloadHistoryIfNeeded();
 
 	void handleScroll();
-	void scrollByTimer();
 	void updateHistoryItemsByTimer();
 
 	[[nodiscard]] Dialogs::EntryState computeDialogsEntryState() const;
@@ -762,9 +758,6 @@ private:
 	Window::SlideDirection _showDirection;
 	QPixmap _cacheUnder, _cacheOver;
 
-	base::Timer _scrollTimer;
-	int32 _scrollDelta = 0;
-
 	MsgId _highlightedMessageId = 0;
 	std::deque<MsgId> _highlightQueue;
 	base::Timer _highlightTimer;

Telegram/SourceFiles/ui/chat/select_scroll_manager.cpp

@@ -0,0 +1,50 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "ui/chat/select_scroll_manager.h"
+
+#include "ui/widgets/scroll_area.h"
+
+namespace Ui {
+
+SelectScrollManager::SelectScrollManager()
+: _timer([=] { scrollByTimer(); }) {
+}
+
+void SelectScrollManager::scrollByTimer() {
+	const auto d = (_delta > 0)
+		? std::min(_delta * 3 / 20 + 1, kMaxScrollSpeed)
+		: std::max(_delta * 3 / 20 - 1, -kMaxScrollSpeed);
+	_scrolls.fire_copy(d);
+}
+
+void SelectScrollManager::checkDeltaScroll(
+		const QPoint &point,
+		int top,
+		int bottom) {
+	const auto diff = point.y() - top;
+	_delta = (diff < 0)
+		? diff
+		: (point.y() >= bottom)
+		? (point.y() - bottom + 1)
+		: 0;
+	if (_delta) {
+		_timer.callEach(15);
+	} else {
+		_timer.cancel();
+	}
+}
+
+void SelectScrollManager::cancel() {
+	_timer.cancel();
+}
+
+rpl::producer<int> SelectScrollManager::scrolls() {
+	return _scrolls.events();
+}
+
+} // namespace Ui

Telegram/SourceFiles/ui/chat/select_scroll_manager.h

@@ -0,0 +1,34 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "base/timer.h"
+
+namespace Ui {
+
+class ScrollArea;
+
+class SelectScrollManager final {
+public:
+	SelectScrollManager();
+
+	void checkDeltaScroll(const QPoint &point, int top, int bottom);
+	void cancel();
+
+	rpl::producer<int> scrolls();
+
+private:
+	void scrollByTimer();
+
+	base::Timer _timer;
+	int _delta = 0;
+	rpl::event_stream<int> _scrolls;
+
+};
+
+} // namespace Ui

Telegram/cmake/td_ui.cmake

@@ -164,6 +164,8 @@ PRIVATE
     ui/chat/pinned_bar.h
     ui/chat/requests_bar.cpp
     ui/chat/requests_bar.h
+    ui/chat/select_scroll_manager.cpp
+    ui/chat/select_scroll_manager.h
     ui/controls/call_mute_button.cpp
     ui/controls/call_mute_button.h
     ui/controls/delete_message_context_action.cpp