Support structured bindings in base::flat_map.

Telegram/SourceFiles/app.cpp

@@ -662,7 +662,7 @@ namespace App {
 					bool found = !h || !h->lastKeyboardFrom;
 					auto botStatus = -1;
 					for (auto i = chat->participants.begin(); i != chat->participants.end();) {
-						auto [user, version] = *i;
+						const auto [user, version] = *i;
 						if (version < pversion) {
 							i = chat->participants.erase(i);
 						} else {
@@ -761,7 +761,7 @@ namespace App {
 					}
 					if (chat->botStatus > 0 && user->botInfo) {
 						int32 botStatus = -1;
-						for (auto [participant, v] : chat->participants) {
+						for (const auto [participant, v] : chat->participants) {
 							if (participant->botInfo) {
 								if (true || botStatus > 0/* || !participant->botInfo->readsAllHistory*/) {
 									botStatus = 2;

Telegram/SourceFiles/base/flat_map.h

@@ -76,6 +76,7 @@ struct flat_multi_map_pair_type {
 
 	const Key first;
 	Value second;
+
 };
 
 template <
@@ -316,6 +317,18 @@ public:
 	}
 	flat_multi_map &operator=(flat_multi_map &&other) = default;
 
+	template <
+		typename Iterator,
+		typename = typename std::iterator_traits<Iterator>::iterator_category>
+	flat_multi_map(Iterator first, Iterator last)
+	: _data(first, last) {
+		std::sort(std::begin(impl()), std::end(impl()), compare());
+	}
+
+	flat_multi_map(std::initializer_list<pair_type> iter)
+	: flat_multi_map(iter.begin(), iter.end()) {
+	}
+
 	size_type size() const {
 		return impl().size();
 	}
@@ -614,6 +627,20 @@ public:
 	using reverse_iterator = typename parent::reverse_iterator;
 	using const_reverse_iterator = typename parent::const_reverse_iterator;
 
+	flat_map() = default;
+
+	template <
+		typename Iterator,
+		typename = typename std::iterator_traits<Iterator>::iterator_category
+	>
+	flat_map(Iterator first, Iterator last) : parent(first, last) {
+		finalize();
+	}
+
+	flat_map(std::initializer_list<pair_type> iter) : parent(iter.begin(), iter.end()) {
+		finalize();
+	}
+
 	using parent::parent;
 	using parent::size;
 	using parent::empty;
@@ -732,6 +759,74 @@ public:
 		return std::move(result);
 	}
 
+private:
+	void finalize() {
+		this->impl().erase(
+			std::unique(
+				std::begin(this->impl()),
+				std::end(this->impl()),
+				[&](auto &&a, auto &&b) {
+					return !this->compare()(a, b);
+				}
+			),
+			std::end(this->impl()));
+	}
+
 };
 
 } // namespace base
+
+// Structured bindings support.
+namespace std {
+
+template <typename Key, typename Value>
+class tuple_size<base::flat_multi_map_pair_type<Key, Value>>
+: public integral_constant<size_t, 2> {
+};
+
+template <typename Key, typename Value>
+class tuple_element<0, base::flat_multi_map_pair_type<Key, Value>> {
+public:
+	using type = const Key;
+};
+
+template <typename Key, typename Value>
+class tuple_element<1, base::flat_multi_map_pair_type<Key, Value>> {
+public:
+	using type = Value;
+};
+
+} // namespace std
+
+// Structured bindings support.
+namespace base {
+namespace details {
+
+template <std::size_t N, typename Key, typename Value>
+using flat_multi_map_pair_element = std::tuple_element_t<
+	N,
+	flat_multi_map_pair_type<Key, Value>>;
+
+} // namespace details
+
+template <std::size_t N, typename Key, typename Value>
+auto get(base::flat_multi_map_pair_type<Key, Value> &value)
+-> details::flat_multi_map_pair_element<N, Key, Value> & {
+	if constexpr (N == 0) {
+		return value.first;
+	} else {
+		return value.second;
+	}
+}
+
+template <std::size_t N, typename Key, typename Value>
+auto get(const base::flat_multi_map_pair_type<Key, Value> &value)
+-> const details::flat_multi_map_pair_element<N, Key, Value> & {
+	if constexpr (N == 0) {
+		return value.first;
+	} else {
+		return value.second;
+	}
+}
+
+} // namespace base

Telegram/SourceFiles/base/flat_map_tests.cpp

@@ -91,3 +91,31 @@ TEST_CASE("flat_maps custom comparator", "[flat_map]") {
 		checkSorted();
 	}
 }
+
+TEST_CASE("flat_maps structured bindings", "[flat_map]") {
+	base::flat_map<int, std::unique_ptr<double>> v;
+	v.emplace(0, std::make_unique<double>(0.));
+	v.emplace(1, std::make_unique<double>(1.));
+
+	SECTION("structred binded range-based for loop") {
+		for (const auto &[key, value] : v) {
+			REQUIRE(key == int(std::round(*value)));
+		}
+	}
+
+	SECTION("non-const structured binded range-based for loop") {
+		base::flat_map<int, int> second = {
+			{ 1, 1 },
+			{ 2, 2 },
+			{ 2, 3 },
+			{ 3, 3 },
+		};
+		REQUIRE(second.size() == 3);
+		//for (auto [a, b] : second) { // #MSVC Bug, reported
+		//	REQUIRE(a == b);
+		//}
+		for (const auto [a, b] : second) {
+			REQUIRE(a == b);
+		}
+	}
+}

Telegram/SourceFiles/boxes/peer_list_controllers.cpp

@@ -656,7 +656,7 @@ void EditChatAdminsBoxController::rebuildRows() {
 	admins.reserve(allAdmins ? _chat->participants.size() : _chat->admins.size());
 	others.reserve(_chat->participants.size());
 
-	for (auto [user, version] : _chat->participants) {
+	for (const auto [user, version] : _chat->participants) {
 		if (user->id == peerFromUser(_chat->creator)) continue;
 		if (_chat->admins.contains(user)) {
 			admins.push_back(user);

Telegram/SourceFiles/history/view/history_view_top_bar_widget.cpp

@@ -765,7 +765,7 @@ void TopBarWidget::updateOnlineDisplay() {
 			const auto self = Auth().user();
 			auto online = 0;
 			auto onlyMe = true;
-			for (auto [user, v] : chat->participants) {
+			for (const auto [user, v] : chat->participants) {
 				if (user->onlineTill > now) {
 					++online;
 					if (onlyMe && user != self) onlyMe = false;
@@ -833,7 +833,7 @@ void TopBarWidget::updateOnlineDisplayTimer() {
 	if (const auto user = _activeChat.peer()->asUser()) {
 		handleUser(user);
 	} else if (auto chat = _activeChat.peer()->asChat()) {
-		for (auto [user, v] : chat->participants) {
+		for (const auto [user, v] : chat->participants) {
 			handleUser(user);
 		}
 	} else if (_activeChat.peer()->isChannel()) {

Telegram/SourceFiles/profile/profile_block_group_members.cpp

@@ -406,7 +406,7 @@ void GroupMembersWidget::fillChatMembers(ChatData *chat) {
 	reserveItemsForSize(chat->participants.size());
 	addUser(chat, Auth().user())->onlineForSort
 		= std::numeric_limits<TimeId>::max();
-	for (auto [user, v] : chat->participants) {
+	for (const auto &[user, v] : chat->participants) {
 		if (!user->isSelf()) {
 			addUser(chat, user);
 		}