On Windows desktop, use wide path strings in Remote Config. (#1316)

* On Windows desktop, use wide path strings in Remote Config.

* Move header to below platform.h.

* Format code.

* On desktop, move Remote Config data into the AppDataDir instead of the current directory.

* Remove extraneous forward reference.

* Format code.

* For debugging, add an international path to Windows runs.

* Fix Mkdir.

* Clean up data directory and make suffix optional.

* Fix usage of AppDataDir without app name.

* Slash.

* Re-add app data prefix.

* Change / to .

* Fix include.

* Fix string.

* Fix string usage

* Remove temporary international directory for testing.

* Add international characters to path.

* Format code.

Author: jonsimantov

app/src/filesystem.h

@@ -20,7 +20,6 @@
 #include <string>
 
 namespace firebase {
-
 /**
  * Returns a system-defined best directory in which to create application
  * data. Values vary wildly across platforms. They include:

remote_config/src/desktop/file_manager.cc

@@ -21,14 +21,33 @@
 #include <string>
 #include <utility>
 
+#include "app/src/filesystem.h"
+#include "app/src/include/firebase/internal/platform.h"
 #include "remote_config/src/desktop/config_data.h"
 
+#if FIREBASE_PLATFORM_WINDOWS
+#include <codecvt>
+#include <locale>
+#endif
+
 namespace firebase {
 namespace remote_config {
 namespace internal {
 
-RemoteConfigFileManager::RemoteConfigFileManager(const std::string& file_path)
-    : file_path_(file_path) {}
+RemoteConfigFileManager::RemoteConfigFileManager(const std::string& filename,
+                                                 const firebase::App& app) {
+  std::string app_data_prefix = std::string(app.options().package_name()) +
+                                "/" + app.name() + "/" + "TẽstPạth";
+  std::string file_path =
+      AppDataDir(app_data_prefix.c_str(), /*should_create=*/true) + "/" +
+      filename;
+#if FIREBASE_PLATFORM_WINDOWS
+  std::wstring_convert<std::codecvt_utf8<wchar_t>> utf8_to_wstring;
+  file_path_ = utf8_to_wstring.from_bytes(file_path);
+#else
+  file_path_ = file_path;
+#endif
+}
 
 bool RemoteConfigFileManager::Load(LayeredConfigs* configs) const {
   std::fstream input(file_path_, std::ios::in | std::ios::binary);

remote_config/src/desktop/file_manager.h

@@ -17,6 +17,8 @@
 
 #include <string>
 
+#include "app/src/include/firebase/app.h"
+#include "app/src/include/firebase/internal/platform.h"
 #include "remote_config/src/desktop/config_data.h"
 
 namespace firebase {
@@ -27,7 +29,8 @@ namespace internal {
 // load from file.
 class RemoteConfigFileManager {
  public:
-  explicit RemoteConfigFileManager(const std::string& file_path);
+  RemoteConfigFileManager(const std::string& file_path,
+                          const firebase::App& app);
 
   // Load `configs` from file. Will return `true` if success.
   bool Load(LayeredConfigs* configs) const;
@@ -36,8 +39,12 @@ class RemoteConfigFileManager {
   bool Save(const LayeredConfigs& configs) const;
 
  private:
-  // Path to file with data.
+  // Path to file with data. On Windows, use a UTF-16 path string.
+#if FIREBASE_PLATFORM_WINDOWS
+  std::wstring file_path_;
+#else
   std::string file_path_;
+#endif
 };
 
 }  // namespace internal

remote_config/src/desktop/remote_config_desktop.cc

@@ -25,6 +25,7 @@
 #include <vector>
 
 #include "app/src/callback.h"
+#include "app/src/include/firebase/internal/platform.h"
 #include "app/src/time.h"
 #include "remote_config/src/common.h"
 #include "remote_config/src/include/firebase/remote_config.h"
@@ -78,7 +79,7 @@ RemoteConfigInternal::RemoteConfigInternal(
 
 RemoteConfigInternal::RemoteConfigInternal(const firebase::App& app)
     : app_(app),
-      file_manager_(kFilePathSuffix),
+      file_manager_(kFilePathSuffix, app),
       is_fetch_process_have_task_(false),
       future_impl_(kRemoteConfigFnCount),
       safe_this_(this),