Repo created

libs/storage/map_files_downloader.hpp

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+#pragma once
+
+#include "storage/downloader_queue_universal.hpp"
+#include "storage/downloading_policy.hpp"
+#include "storage/queued_country.hpp"
+
+#include "platform/downloader_defines.hpp"
+#include "platform/http_request.hpp"
+#include "platform/safe_callback.hpp"
+
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "platform/servers_list.hpp"
+
+namespace storage
+{
+using downloader::MetaConfig;
+
+// This interface encapsulates HTTP routines for receiving servers
+// URLs and downloading a single map file.
+class MapFilesDownloader
+{
+public:
+  // Denotes bytes downloaded and total number of bytes.
+  using ServersList = std::vector<std::string>;
+  using MetaConfigCallback = platform::SafeCallback<void(MetaConfig const & metaConfig)>;
+
+  virtual ~MapFilesDownloader() = default;
+
+  /// Asynchronously downloads a map file (first queries the metaserver
+  /// for the map servers list, if it haven't been done before),
+  /// periodically invokes onProgress callback and finally invokes onDownloaded
+  /// callback. Both callbacks will be invoked on the main thread.
+  void DownloadMapFile(QueuedCountry && queuedCountry);
+
+  // Removes item from m_quarantine queue when list of servers is not received.
+  // Parent method must be called into override method.
+  virtual void Remove(CountryId const & id);
+
+  // Clears m_quarantine queue when list of servers is not received.
+  // Parent method must be called into override method.
+  virtual void Clear();
+
+  // Returns m_quarantine queue when list of servers is not received.
+  // Parent method must be called into override method.
+  virtual QueueInterface const & GetQueue() const;
+
+  /**
+   * @brief Async file download as string buffer (for small files only).
+   * Request can be skipped if current servers list is empty.
+   * Callback will be skipped on download error.
+   * NOTE: not in use at the moment.
+   * @param[in]  url        Final url part like "index.json" or "maps/210415/countries.txt".
+   * @param[in]  forceReset True - force reset current request, if any.
+   */
+  void DownloadAsString(std::string url, std::function<bool(std::string const &)> && callback, bool forceReset = false);
+
+  // Used in tests only.
+  void SetServersList(ServersList const & serversList);
+
+  void SetDownloadingPolicy(DownloadingPolicy * policy);
+  void SetDataVersion(int64_t version) { m_dataVersion = version; }
+
+  /// @name Legacy functions for Android resources downloading routine (initial World download).
+  /// @{
+  void EnsureMetaConfigReady(std::function<void()> && callback);
+  std::vector<std::string> MakeUrlListLegacy(std::string const & fileName) const;
+  /// @}
+
+protected:
+  bool IsDownloadingAllowed() const;
+  // Produces download urls for all servers.
+  std::vector<std::string> MakeUrlList(std::string const & relativeUrl) const;
+
+  // Synchronously loads a list of map servers from the metaserver.
+  // On dl failure fallbacks to the hardcoded list.
+  MetaConfig LoadMetaConfig();
+
+private:
+  /**
+   * @brief This method is blocking and should be called on network thread.
+   * Default implementation receives a list of all servers that can be asked
+   * for a map file and invokes callback on the main thread (@see MetaConfigCallback as SafeCallback).
+   */
+  virtual void GetMetaConfig(MetaConfigCallback const & callback);
+  /// Asynchronously downloads the file and saves result to provided directory.
+  virtual void Download(QueuedCountry && queuedCountry) = 0;
+
+  /// @param[in]  callback  Called in main thread (@see GetMetaConfig).
+  void RunMetaConfigAsync(std::function<void()> && callback);
+
+  /// Current file downloading request for DownloadAsString.
+  using RequestT = downloader::HttpRequest;
+  std::unique_ptr<RequestT> m_fileRequest;
+
+  ServersList m_serversList;
+  int64_t m_dataVersion = 0;
+
+  /// Used as guard for m_serversList assign.
+  std::atomic_bool m_isMetaConfigRequested = false;
+
+  DownloadingPolicy * m_downloadingPolicy = nullptr;
+
+  // This queue accumulates download requests before
+  // the servers list is received on the network thread.
+  Queue m_pendingRequests;
+};
+}  // namespace storage