[core] Allow overriding map metaserver URL and reset downloader cache

- Add custom meta server API.
- Implement override.
- Add reset hook and implement reset.
- Expose reset from Storage.
- Let JNI set URL and reset cache.

Signed-off-by: NoelClick <dev@noel.click>

android/sdk/src/main/cpp/app/organicmaps/sdk/Framework.cpp

@@ -1505,6 +1505,22 @@ JNIEXPORT void JNICALL Java_app_organicmaps_sdk_Framework_nativeGet3dMode(JNIEnv
   env->SetBooleanField(result, buildingsField, buildings);
 }
 
+JNIEXPORT void JNICALL Java_app_organicmaps_sdk_Framework_nativeSetCustomMapDownloadUrl(JNIEnv * env, jclass, 
+                                                                                        jstring url)
+{
+  std::string const nativeUrl = jni::ToNativeString(env, url);
+  GetPlatform().SetCustomMetaServerUrl(nativeUrl);
+
+  if (g_framework)
+  {
+    frm()->GetStorage().ResetMapDownloadMetaConfig();
+  }
+  else
+  {
+    LOG(LINFO, ("nativeSetCustomMapDownloadUrl: framework not created yet, skipping ResetMapDownloadMetaConfig"));
+  }
+}
+
 JNIEXPORT void JNICALL Java_app_organicmaps_sdk_Framework_nativeSetAutoZoomEnabled(JNIEnv * env, jclass,
                                                                                    jboolean enabled)
 {

libs/platform/platform.cpp

@@ -49,6 +49,11 @@ bool GetFileTypeChecked(std::string const & path, Platform::EFileType & type)
 }
 }  // namespace
 
+namespace
+{
+    std::string g_customMetaServerUrl;
+} // namespace
+
 // static
 Platform::EError Platform::ErrnoToError()
 {
@@ -150,8 +155,16 @@ std::string Platform::ReadPathForFile(std::string const & file, std::string sear
                                 "\nr: ", m_resourcesDir, "\ns: ", m_settingsDir));
 }
 
+void Platform::SetCustomMetaServerUrl(std::string const & url)
+{
+    g_customMetaServerUrl = url;
+}
+
 std::string Platform::MetaServerUrl() const
 {
+  if (!g_customMetaServerUrl.empty())
+    return g_customMetaServerUrl;
+
   return METASERVER_URL;
 }
 

libs/platform/platform.hpp

@@ -268,6 +268,9 @@ public:
   /// @return integer version in yyMMdd format.
   int32_t IntVersion() const;
 
+  /// Set custom meta server url to allow user-defined download servers
+  void SetCustomMetaServerUrl(std::string const & url);
+
   /// @return url for clients to download maps
   std::string MetaServerUrl() const;
 

libs/storage/map_files_downloader.cpp

@@ -190,4 +190,10 @@ void MapFilesDownloader::GetMetaConfig(MetaConfigCallback const & callback)
   callback(LoadMetaConfig());
 }
 
+void MapFilesDownloader::ResetMetaConfig()
+{
+    m_serversList.clear();
+    m_isMetaConfigRequested = false;
+}
+
 }  // namespace storage

libs/storage/map_files_downloader.hpp

@@ -66,6 +66,9 @@ public:
   void SetDownloadingPolicy(DownloadingPolicy * policy);
   void SetDataVersion(int64_t version) { m_dataVersion = version; }
 
+  /// Reset after changes, e.g. map download URL.
+  void ResetMetaConfig();
+
   /// @name Legacy functions for Android resources downloading routine (initial World download).
   /// @{
   void EnsureMetaConfigReady(std::function<void()> && callback);

libs/storage/storage.hpp

@@ -585,6 +585,12 @@ public:
 
   void RestoreDownloadQueue();
 
+  void ResetMapDownloadMetaConfig()
+  {
+    if (m_downloader)
+      m_downloader->ResetMetaConfig();
+  }
+
 protected:
   void OnFinishDownloading();