file_sys: Cleanup to better match Switch file system constructs.

file_sys: Add factory class for RomFS file system.

src/core/file_sys/filesystem.h

@@ -0,0 +1,190 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+#include "common/bit_field.h"
+#include "common/common_types.h"
+#include "common/swap.h"
+#include "core/hle/result.h"
+
+namespace FileSys {
+
+class StorageBackend;
+class DirectoryBackend;
+
+// Path string type
+enum LowPathType : u32 {
+    Invalid = 0,
+    Empty = 1,
+    Binary = 2,
+    Char = 3,
+    Wchar = 4,
+};
+
+union Mode {
+    u32 hex;
+    BitField<0, 1, u32> read_flag;
+    BitField<1, 1, u32> write_flag;
+    BitField<2, 1, u32> create_flag;
+};
+
+class Path {
+public:
+    Path() : type(Invalid) {}
+    Path(const char* path) : type(Char), string(path) {}
+    Path(std::vector<u8> binary_data) : type(Binary), binary(std::move(binary_data)) {}
+    Path(LowPathType type, u32 size, u32 pointer);
+
+    LowPathType GetType() const {
+        return type;
+    }
+
+    /**
+     * Gets the string representation of the path for debugging
+     * @return String representation of the path for debugging
+     */
+    std::string DebugStr() const;
+
+    std::string AsString() const;
+    std::u16string AsU16Str() const;
+    std::vector<u8> AsBinary() const;
+
+private:
+    LowPathType type;
+    std::vector<u8> binary;
+    std::string string;
+    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 Path& 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 Path& 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 Path& 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 Path& src_path, const Path& 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 Path& path,
+                                                          const 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 Path& path) const = 0;
+
+    /**
+     * Get the free space
+     * @return The number of free bytes in the archive
+     */
+    virtual u64 GetFreeSpaceSize() 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
+     * @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;
+
+    /**
+     * 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