Method requestTopicMessages

Telegram/SourceFiles/export/export_api_wrap.cpp:2324–2412

}

void ApiWrap::requestTopicMessages(
		PeerId peerId,
		MTPInputPeer inputPeer,
		int32 topicRootId,
		FnMut<bool(int count)> start,
		Fn<bool(DownloadProgress)> progress,
		Fn<bool(Data::MessagesSlice&&)> slice,
		FnMut<void()> done) {
	Expects(_topicProcess == nullptr);
	Expects(_selfId.has_value());

	_topicProcess = std::make_unique<TopicProcess>();
	_topicProcess->context.selfPeerId = peerFromUser(*_selfId);
	_topicProcess->peerId = peerId;
	_topicProcess->inputPeer = inputPeer;
	_topicProcess->topicRootId = topicRootId;
	_topicProcess->relativePath = "chats/chat_"
		+ QString::number(peerId.value)
		+ "/topic_"
		+ QString::number(topicRootId)
		+ "/";
	_topicProcess->start = std::move(start);
	_topicProcess->fileProgress = std::move(progress);
	_topicProcess->handleSlice = std::move(slice);
	_topicProcess->done = std::move(done);

	mainRequest(MTPchannels_GetMessages(
		MTP_inputChannel(
			inputPeer.c_inputPeerChannel().vchannel_id(),
			inputPeer.c_inputPeerChannel().vaccess_hash()),
		MTP_vector<MTPInputMessage>(
			1,
			MTP_inputMessageID(MTP_int(topicRootId)))
	)).done([=](const MTPmessages_Messages &rootResult) {
		Expects(_topicProcess != nullptr);

		auto rootSlice = rootResult.match([&](
				const MTPDmessages_messagesNotModified &) {
			return Data::MessagesSlice();
		}, [&](const auto &data) {
			return Data::ParseMessagesSlice(
				_topicProcess->context,
				data.vmessages(),
				data.vusers(),
				data.vchats(),
				_topicProcess->relativePath);
		});

		auto rootSlicePtr = std::make_shared<Data::MessagesSlice>(
			std::move(rootSlice));

		requestTopicReplies(
			0,
			0,
			kMessagesSliceLimit,
			[=](const MTPmessages_Messages &result) {
				Expects(_topicProcess != nullptr);