FS: Make EnsureSaveData create the savedata folder when called for the first time.

src/core/file_sys/filesystem.h

@@ -183,10 +183,9 @@ public:
     /**
      * Deletes the archive contents and then re-creates the base folder
      * @param path Path to the archive
-     * @param format_info Format information for the new archive
      * @return ResultCode of the operation, 0 on success
      */
-    virtual ResultCode Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) = 0;
+    virtual ResultCode Format(const Path& path) = 0;
 
     /**
      * Retrieves the format info about the archive with the specified path

src/core/file_sys/romfs_factory.cpp

@@ -23,7 +23,7 @@ ResultVal<std::unique_ptr<FileSystemBackend>> RomFS_Factory::Open(const Path& pa
     return MakeResult<std::unique_ptr<FileSystemBackend>>(std::move(archive));
 }
 
-ResultCode RomFS_Factory::Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) {
+ResultCode RomFS_Factory::Format(const Path& path) {
     LOG_ERROR(Service_FS, "Unimplemented Format archive %s", GetName().c_str());
     // TODO(bunnei): Find the right error code for this
     return ResultCode(-1);

src/core/file_sys/romfs_factory.h

@@ -23,7 +23,7 @@ public:
         return "ArchiveFactory_RomFS";
     }
     ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) override;
-    ResultCode Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) override;
+    ResultCode Format(const Path& path) override;
     ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
 
 private:

src/core/file_sys/savedata_factory.cpp

@@ -17,26 +17,40 @@ SaveData_Factory::SaveData_Factory(std::string nand_directory)
     : nand_directory(std::move(nand_directory)) {}
 
 ResultVal<std::unique_ptr<FileSystemBackend>> SaveData_Factory::Open(const Path& path) {
-    u64 title_id = Kernel::g_current_process->program_id;
-    // TODO(Subv): Somehow obtain this value.
-    u32 user = 0;
-    std::string save_directory = Common::StringFromFormat("%ssave/%016" PRIX64 "/%08X",
-                                                          nand_directory.c_str(), title_id, user);
+    std::string save_directory = GetFullPath();
+    // Return an error if the save data doesn't actually exist.
+    if (!FileUtil::IsDirectory(save_directory)) {
+        // TODO(Subv): Find out correct error code.
+        return ResultCode(-1);
+    }
+
     auto archive = std::make_unique<Disk_FileSystem>(save_directory);
     return MakeResult<std::unique_ptr<FileSystemBackend>>(std::move(archive));
 }
 
-ResultCode SaveData_Factory::Format(const Path& path,
-                                    const FileSys::ArchiveFormatInfo& format_info) {
-    LOG_ERROR(Service_FS, "Unimplemented Format archive %s", GetName().c_str());
-    // TODO(bunnei): Find the right error code for this
+ResultCode SaveData_Factory::Format(const Path& path) {
+    LOG_WARNING(Service_FS, "Format archive %s", GetName().c_str());
+    // Create the save data directory.
+    if (!FileUtil::CreateFullPath(GetFullPath())) {
+        // TODO(Subv): Find the correct error code.
         return ResultCode(-1);
     }
 
+    return RESULT_SUCCESS;
+}
+
 ResultVal<ArchiveFormatInfo> SaveData_Factory::GetFormatInfo(const Path& path) const {
     LOG_ERROR(Service_FS, "Unimplemented GetFormatInfo archive %s", GetName().c_str());
     // TODO(bunnei): Find the right error code for this
     return ResultCode(-1);
 }
 
+std::string SaveData_Factory::GetFullPath() const {
+    u64 title_id = Kernel::g_current_process->program_id;
+    // TODO(Subv): Somehow obtain this value.
+    u32 user = 0;
+    return Common::StringFromFormat("%ssave/%016" PRIX64 "/%08X/", nand_directory.c_str(), title_id,
+                                    user);
+}
+
 } // namespace FileSys

src/core/file_sys/savedata_factory.h

@@ -21,11 +21,13 @@ public:
         return "SaveData_Factory";
     }
     ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) override;
-    ResultCode Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) override;
+    ResultCode Format(const Path& path) override;
     ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
 
 private:
     std::string nand_directory;
+
+    std::string GetFullPath() const;
 };
 
 } // namespace FileSys

src/core/hle/service/am/am.cpp

@@ -2,12 +2,15 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <cinttypes>
+#include "core/file_sys/filesystem.h"
 #include "core/hle/ipc_helpers.h"
 #include "core/hle/kernel/event.h"
 #include "core/hle/service/am/am.h"
 #include "core/hle/service/am/applet_ae.h"
 #include "core/hle/service/am/applet_oe.h"
 #include "core/hle/service/apm/apm.h"
+#include "core/hle/service/filesystem/filesystem.h"
 #include "core/hle/service/nvflinger/nvflinger.h"
 
 namespace Service {
@@ -416,9 +419,24 @@ void IApplicationFunctions::PopLaunchParameter(Kernel::HLERequestContext& ctx) {
 }
 
 void IApplicationFunctions::EnsureSaveData(Kernel::HLERequestContext& ctx) {
-    LOG_WARNING(Service, "(STUBBED) called");
+    IPC::RequestParser rp{ctx};
+    u128 uid = rp.PopRaw<u128>();
+
+    LOG_WARNING(Service, "(STUBBED) called uid = %016" PRIX64 "%016" PRIX64, uid[1], uid[0]);
+
     IPC::ResponseBuilder rb{ctx, 4};
+
+    FileSys::Path unused;
+    auto savedata = FileSystem::OpenFileSystem(FileSystem::Type::SaveData, unused);
+    if (savedata.Failed()) {
+        // Create the save data and return an error indicating that the operation was performed.
+        FileSystem::FormatFileSystem(FileSystem::Type::SaveData);
+        // TODO(Subv): Find out the correct error code for this.
+        rb.Push(ResultCode(ErrorModule::FS, 40));
+    } else {
         rb.Push(RESULT_SUCCESS);
+    }
+
     rb.Push<u64>(0);
 }
 

src/core/hle/service/filesystem/filesystem.cpp

@@ -43,6 +43,19 @@ ResultVal<std::unique_ptr<FileSys::FileSystemBackend>> OpenFileSystem(Type type,
     return itr->second->Open(path);
 }
 
+ResultCode FormatFileSystem(Type type) {
+    LOG_TRACE(Service_FS, "Formatting FileSystem with type=%d", type);
+
+    auto itr = filesystem_map.find(type);
+    if (itr == filesystem_map.end()) {
+        // TODO(bunnei): Find a better error code for this
+        return ResultCode(-1);
+    }
+
+    FileSys::Path unused;
+    return itr->second->Format(unused);
+}
+
 void RegisterFileSystems() {
     filesystem_map.clear();
 

src/core/hle/service/filesystem/filesystem.h

@@ -44,6 +44,13 @@ ResultCode RegisterFileSystem(std::unique_ptr<FileSys::FileSystemFactory>&& fact
 ResultVal<std::unique_ptr<FileSys::FileSystemBackend>> OpenFileSystem(Type type,
                                                                       FileSys::Path& path);
 
+/**
+ * Formats a file system
+ * @param type Type of the file system to format
+ * @return ResultCode of the operation
+ */
+ResultCode FormatFileSystem(Type type);
+
 /// Registers all Filesystem services with the specified service manager.
 void InstallInterfaces(SM::ServiceManager& service_manager);