Method sharedDocument

Telegram/SourceFiles/data/data_streaming.cpp:119–148

template <typename Data>
[[nodiscard]] std::shared_ptr<Streaming::Document> Streaming::sharedDocument(
		base::flat_map<not_null<Data*>, std::weak_ptr<Document>> &documents,
		base::flat_map<not_null<Data*>, std::weak_ptr<Reader>> &readers,
		not_null<Data*> data,
		DocumentData *original,
		HistoryItem *context,
		FileOrigin origin) {
	auto otherQualities = LookupOtherQualities(original, data, context);
	const auto i = documents.find(data);
	if (i != end(documents)) {
		if (auto result = i->second.lock()) {
			if (!otherQualities.empty()) {
				result->setOtherQualities(std::move(otherQualities));
			}
			return result;
		}
	}
	auto reader = sharedReader(readers, data, origin);
	if (!reader) {
		return nullptr;
	}
	auto result = std::make_shared<Document>(
		data,
		std::move(reader),
		std::move(otherQualities));
	if (!PruneDestroyedAndSet(documents, data, result)) {
		documents.emplace_or_assign(data, result);
	}
	return result;
}

template <typename Data>
void Streaming::keepAlive(