Add rpl::take(count).

Telegram/SourceFiles/boxes/change_phone_box.cpp

@@ -20,6 +20,9 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 */
 #include "boxes/change_phone_box.h"
 
+#include <rpl/filter.h>
+#include <rpl/mappers.h>
+#include <rpl/take.h>
 #include "lang/lang_keys.h"
 #include "styles/style_boxes.h"
 #include "ui/widgets/labels.h"
@@ -39,13 +42,19 @@ void createErrorLabel(
 		int y) {
 	if (label) {
 		label->hide(anim::type::normal);
-		auto context = label.data();
-		App::CallDelayed(
-			st::fadeWrapDuration,
-			context,
-			[old = std::move(label)]() mutable {
-				old.destroy();
-			});
+
+		auto saved = label.data();
+		auto destroy = [old = std::move(label)]() mutable {
+			old.destroyDelayed();
+		};
+
+		using namespace rpl::mappers;
+		saved->shownValue()
+			| rpl::filter($1 == false)
+			| rpl::take(1)
+			| rpl::start_with_done(
+				std::move(destroy),
+				saved->lifetime());
 	}
 	if (!text.isEmpty()) {
 		label.create(

Telegram/SourceFiles/rpl/operators_tests.cpp

@@ -388,4 +388,18 @@ TEST_CASE("basic operators tests", "[rpl::operators]") {
 		}
 		REQUIRE(*sum == "0-11-22-3");
 	}
+
+	SECTION("take test") {
+		auto sum = std::make_shared<std::string>("");
+		{
+			rpl::lifetime lifetime;
+			rpl::ints(10) | take(3)
+				| start_with_next_done([=](int value) {
+					*sum += std::to_string(value);
+				}, [=] {
+					*sum += "done";
+				}, lifetime);
+		}
+		REQUIRE(*sum == "012done");
+	}
 }

Telegram/SourceFiles/rpl/rpl.h

@@ -30,6 +30,7 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 #include <rpl/fail.h>
 #include <rpl/never.h>
 
+#include <rpl/take.h>
 #include <rpl/then.h>
 #include <rpl/deferred.h>
 #include <rpl/map.h>

Telegram/SourceFiles/rpl/take.h

@@ -0,0 +1,74 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop version of Telegram messaging app, see https://telegram.org
+
+Telegram Desktop is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+It is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+In addition, as a special exception, the copyright holders give permission
+to link the code of portions of this program with the OpenSSL library.
+
+Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
+Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
+*/
+#pragma once
+
+namespace rpl {
+namespace details {
+
+class take_helper {
+public:
+	take_helper(int count) : _count(count) {
+	}
+
+	template <
+		typename Value,
+		typename Error,
+		typename Generator>
+	auto operator()(producer<Value, Error, Generator> &&initial) {
+		return make_producer<Value, Error>([
+			initial = std::move(initial),
+			limit = _count
+		](const auto &consumer) mutable {
+			auto count = consumer.template make_state<int>(limit);
+			return std::move(initial).start(
+			[consumer, count](auto &&value) {
+				auto left = (*count)--;
+				if (left) {
+					consumer.put_next_forward(
+						std::forward<decltype(value)>(value));
+					--left;
+				}
+				if (!left) {
+					consumer.put_done();
+				}
+			}, [consumer](auto &&error) {
+				consumer.put_error_forward(
+					std::forward<decltype(error)>(error));
+			}, [consumer] {
+				consumer.put_done();
+			});
+		});
+	}
+
+private:
+	int _count = 0;
+
+};
+
+} // namespace details
+inline auto take(int count)
+-> details::take_helper {
+	Expects(count >= 0);
+	return details::take_helper(count);
+}
+
+
+} // namespace rpl

Telegram/SourceFiles/ui/abstract_button.cpp

@@ -20,8 +20,20 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 */
 #include "ui/abstract_button.h"
 
+#include <rpl/filter.h>
+#include <rpl/mappers.h>
+
 namespace Ui {
 
+AbstractButton::AbstractButton(QWidget *parent) : RpWidget(parent) {
+	setMouseTracking(true);
+
+	using namespace rpl::mappers;
+	shownValue()
+		| rpl::filter($1 == false)
+		| rpl::start_with_next([this] { clearState(); }, lifetime());
+}
+
 void AbstractButton::leaveEventHook(QEvent *e) {
 	if (_state & StateFlag::Down) return;
 

Telegram/SourceFiles/ui/abstract_button.h

@@ -30,9 +30,7 @@ class AbstractButton : public RpWidget {
 	Q_OBJECT
 
 public:
-	AbstractButton(QWidget *parent) : RpWidget(parent) {
-		setMouseTracking(true);
-	}
+	AbstractButton(QWidget *parent);
 
 	Qt::KeyboardModifiers clickModifiers() const {
 		return _modifiers;
@@ -58,13 +56,6 @@ public:
 		_clickedCallback = std::move(callback);
 	}
 
-	void setVisible(bool visible) override {
-		TWidget::setVisible(visible);
-		if (!visible) {
-			clearState();
-		}
-	}
-
 	auto clicks() const {
 		return _clicks.events();
 	}

Telegram/SourceFiles/ui/effects/fade_animation.cpp

@@ -100,7 +100,6 @@ void FadeAnimation::stopAnimation() {
 	_animation.finish();
 	if (!_cache.isNull()) {
 		_cache = QPixmap();
-		updateCallback();
 		if (_visible) {
 			_widget->showChildren();
 		}

Telegram/SourceFiles/ui/rp_widget.h

@@ -76,6 +76,10 @@ public:
 	virtual rpl::producer<int> desiredHeightValue() const {
 		return heightValue();
 	}
+	auto shownValue() const {
+		auto &stream = eventStreams().shown;
+		return stream.events_starting_with(!this->isHidden());
+	}
 
 	auto paintRequest() const {
 		return eventStreams().paint.events();
@@ -85,6 +89,17 @@ public:
 		return eventStreams().alive.events();
 	}
 
+	void setVisible(bool visible) final override {
+		auto wasVisible = !this->isHidden();
+		Parent::setVisible(visible);
+		auto nowVisible = !this->isHidden();
+		if (nowVisible != wasVisible) {
+			if (auto streams = _eventStreams.get()) {
+				streams->shown.fire_copy(nowVisible);
+			}
+		}
+	}
+
 	template <typename Error, typename Generator>
 	void showOn(rpl::producer<bool, Error, Generator> &&shown) {
 		std::move(shown)
@@ -133,6 +148,7 @@ private:
 	struct EventStreams {
 		rpl::event_stream<QRect> geometry;
 		rpl::event_stream<QRect> paint;
+		rpl::event_stream<bool> shown;
 		rpl::event_stream<> alive;
 	};
 	struct LifetimeHolder {

Telegram/gyp/tests/tests.gyp

@@ -121,6 +121,7 @@
       '<(src_loc)/rpl/producer_tests.cpp',
       '<(src_loc)/rpl/range.h',
       '<(src_loc)/rpl/rpl.h',
+      '<(src_loc)/rpl/take.h',
       '<(src_loc)/rpl/then.h',
       '<(src_loc)/rpl/type_erased.h',
       '<(src_loc)/rpl/variable.h',