Revert "Virtual Filesystem (#597)"

This reverts commit 77c684c114.

src/core/file_sys/filesystem.h

@@ -66,4 +66,136 @@ private:
     std::u16string u16str;
 };
 
+/// Parameters of the archive, as specified in the Create or Format call.
+struct ArchiveFormatInfo {
+    u32_le total_size;         ///< The pre-defined size of the archive.
+    u32_le number_directories; ///< The pre-defined number of directories in the archive.
+    u32_le number_files;       ///< The pre-defined number of files in the archive.
+    u8 duplicate_data;         ///< Whether the archive should duplicate the data.
+};
+static_assert(std::is_pod<ArchiveFormatInfo>::value, "ArchiveFormatInfo is not POD");
+
+class FileSystemBackend : NonCopyable {
+public:
+    virtual ~FileSystemBackend() {}
+
+    /**
+     * Get a descriptive name for the archive (e.g. "RomFS", "SaveData", etc.)
+     */
+    virtual std::string GetName() const = 0;
+
+    /**
+     * Create a file specified by its path
+     * @param path Path relative to the Archive
+     * @param size The size of the new file, filled with zeroes
+     * @return Result of the operation
+     */
+    virtual ResultCode CreateFile(const std::string& path, u64 size) const = 0;
+
+    /**
+     * Delete a file specified by its path
+     * @param path Path relative to the archive
+     * @return Result of the operation
+     */
+    virtual ResultCode DeleteFile(const std::string& path) const = 0;
+
+    /**
+     * Create a directory specified by its path
+     * @param path Path relative to the archive
+     * @return Result of the operation
+     */
+    virtual ResultCode CreateDirectory(const std::string& path) const = 0;
+
+    /**
+     * Delete a directory specified by its path
+     * @param path Path relative to the archive
+     * @return Result of the operation
+     */
+    virtual ResultCode DeleteDirectory(const Path& path) const = 0;
+
+    /**
+     * Delete a directory specified by its path and anything under it
+     * @param path Path relative to the archive
+     * @return Result of the operation
+     */
+    virtual ResultCode DeleteDirectoryRecursively(const Path& path) const = 0;
+
+    /**
+     * Rename a File specified by its path
+     * @param src_path Source path relative to the archive
+     * @param dest_path Destination path relative to the archive
+     * @return Result of the operation
+     */
+    virtual ResultCode RenameFile(const std::string& src_path,
+                                  const std::string& dest_path) const = 0;
+
+    /**
+     * Rename a Directory specified by its path
+     * @param src_path Source path relative to the archive
+     * @param dest_path Destination path relative to the archive
+     * @return Result of the operation
+     */
+    virtual ResultCode RenameDirectory(const Path& src_path, const Path& dest_path) const = 0;
+
+    /**
+     * Open a file specified by its path, using the specified mode
+     * @param path Path relative to the archive
+     * @param mode Mode to open the file with
+     * @return Opened file, or error code
+     */
+    virtual ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
+                                                                Mode mode) const = 0;
+
+    /**
+     * Open a directory specified by its path
+     * @param path Path relative to the archive
+     * @return Opened directory, or error code
+     */
+    virtual ResultVal<std::unique_ptr<DirectoryBackend>> OpenDirectory(
+        const std::string& path) const = 0;
+
+    /**
+     * Get the free space
+     * @return The number of free bytes in the archive
+     */
+    virtual u64 GetFreeSpaceSize() const = 0;
+
+    /**
+     * Get the type of the specified path
+     * @return The type of the specified path or error code
+     */
+    virtual ResultVal<EntryType> GetEntryType(const std::string& path) const = 0;
+};
+
+class FileSystemFactory : NonCopyable {
+public:
+    virtual ~FileSystemFactory() {}
+
+    /**
+     * Get a descriptive name for the archive (e.g. "RomFS", "SaveData", etc.)
+     */
+    virtual std::string GetName() const = 0;
+
+    /**
+     * Tries to open the archive of this type with the specified path
+     * @param path Path to the archive
+     * @return An ArchiveBackend corresponding operating specified archive path.
+     */
+    virtual ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) = 0;
+
+    /**
+     * Deletes the archive contents and then re-creates the base folder
+     * @param path Path to the archive
+     * @return ResultCode of the operation, 0 on success
+     */
+    virtual ResultCode Format(const Path& path) = 0;
+
+    /**
+     * Retrieves the format info about the archive with the specified path
+     * @param path Path to the archive
+     * @return Format information about the archive or error code
+     */
+    virtual ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const = 0;
+};
+
 } // namespace FileSys