[core] Treat custom map download URL as CDN base, not meta server

- Update `MapFilesDownloader::LoadMetaConfig()` to skip the metaserver when a
  custom base URL is set and build MetaConfig with that URL as the only server.
- Keep the existing metaserver-based behavior when no custom base URL is set.

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

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

@@ -1508,8 +1508,8 @@ JNIEXPORT void JNICALL Java_app_organicmaps_sdk_Framework_nativeGet3dMode(JNIEnv
 JNIEXPORT void JNICALL Java_app_organicmaps_sdk_Framework_nativeSetCustomMapDownloadUrl(JNIEnv * env, jclass, 
                                                                                         jstring url)
 {
-  std::string const nativeUrl = jni::ToNativeString(env, url);
+  std::string nativeUrl = jni::ToNativeString(env, url);
-  GetPlatform().SetCustomMetaServerUrl(nativeUrl);
+  GetPlatform().SetCustomMapServerUrl(nativeUrl);
 
   if (g_framework)
   {

libs/platform/platform.cpp

@@ -155,16 +155,19 @@ std::string Platform::ReadPathForFile(std::string const & file, std::string sear
                                 "\nr: ", m_resourcesDir, "\ns: ", m_settingsDir));
 }
 
-void Platform::SetCustomMetaServerUrl(std::string const & url)
+void Platform::SetCustomMapServerUrl(std::string & url)
 {
-    g_customMetaServerUrl = url;
+    strings::Trim(url);
+    m_customMapServerUrl = std::move(url);
+}
+
+std::string const & Platform::CustomMapServerUrl() const
+{
+  return m_customMapServerUrl;
 }
 
 std::string Platform::MetaServerUrl() const
 {
-  if (!g_customMetaServerUrl.empty())
-    return g_customMetaServerUrl;
-
   return METASERVER_URL;
 }
 

libs/platform/platform.hpp

@@ -268,8 +268,9 @@ public:
   /// @return integer version in yyMMdd format.
   int32_t IntVersion() const;
 
-  /// Set custom meta server url to allow user-defined download servers
+  /// Set custom map server url to allow user-defined download servers
-  void SetCustomMetaServerUrl(std::string const & url);
+  void SetCustomMapServerUrl(std::string & url);
+  std::string const & CustomMapServerUrl() const;
 
   /// @return url for clients to download maps
   std::string MetaServerUrl() const;
@@ -342,6 +343,8 @@ private:
   void ShutdownThreads();
 
   void GetSystemFontNames(FilesList & res) const;
+
+  std::string m_customMapServerUrl;
 };
 
 std::string DebugPrint(Platform::EError err);

libs/storage/map_files_downloader.cpp

@@ -156,6 +156,26 @@ std::string GetAcceptLanguage()
 MetaConfig MapFilesDownloader::LoadMetaConfig()
 {
   Platform & pl = GetPlatform();
+  std::optional<MetaConfig> metaConfig;
+
+  std::string const customServer = pl.CustomMapServerUrl();
+
+  if (!customServer.empty())
+  {
+    LOG(LINFO, ("Using custom map server URL:", customServer));
+
+    // Reuse default meta settings (timeouts, other endpoints) and override servers
+    metaConfig = downloader::ParseMetaConfig(pl.DefaultUrlsJSON());
+    CHECK(metaConfig, ());
+
+    metaConfig->m_serversList.clear();
+    metaConfig->m_serversList.push_back(customServer);
+
+    LOG(LINFO, ("Got servers list (custom server):", metaConfig->m_serversList));
+    CHECK(!metaConfig->m_serversList.empty(), ());
+    return *metaConfig;
+  }
+
   std::string const metaServerUrl = pl.MetaServerUrl();
   std::string httpResult;
 
@@ -170,7 +190,7 @@ MetaConfig MapFilesDownloader::LoadMetaConfig()
     request.RunHttpRequest(httpResult);
   }
 
-  std::optional<MetaConfig> metaConfig = downloader::ParseMetaConfig(httpResult);
+  metaConfig = downloader::ParseMetaConfig(httpResult);
   if (!metaConfig)
   {
     metaConfig = downloader::ParseMetaConfig(pl.DefaultUrlsJSON());