Virtual Filesystem (#597)

* Add VfsFile and VfsDirectory classes

* Finish abstract Vfs classes

* Implement RealVfsFile (computer fs backend)

* Finish RealVfsFile and RealVfsDirectory

* Finished OffsetVfsFile

* More changes

* Fix import paths

* Major refactor

* Remove double const

* Use experimental/filesystem or filesystem depending on compiler

* Port partition_filesystem

* More changes

* More Overhaul

* FSP_SRV fixes

* Fixes and testing

* Try to get filesystem to compile

* Filesystem on linux

* Remove std::filesystem and document/test

* Compile fixes

* Missing include

* Bug fixes

* Fixes

* Rename v_file and v_dir

* clang-format fix

* Rename NGLOG_* to LOG_*

* Most review changes

* Fix TODO

* Guess 'main' to be Directory by filename

23 files changed, 1127 insertions, 996 deletions

diff --git a/src/core/file_sys/content_archive.cpp b/src/core/file_sys/content_archive.cpp
new file mode 100644
index 000000000..b45b83a26
--- /dev/null
+++ b/src/core/file_sys/content_archive.cpp
@@ -0,0 +1,164 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/logging/log.h"
+#include "core/file_sys/content_archive.h"
+#include "core/file_sys/vfs_offset.h"
+#include "core/loader/loader.h"
+
+namespace FileSys {
+
+// Media offsets in headers are stored divided by 512. Mult. by this to get real offset.
+constexpr u64 MEDIA_OFFSET_MULTIPLIER = 0x200;
+
+constexpr u64 SECTION_HEADER_SIZE = 0x200;
+constexpr u64 SECTION_HEADER_OFFSET = 0x400;
+
+constexpr u32 IVFC_MAX_LEVEL = 6;
+
+enum class NCASectionFilesystemType : u8 { PFS0 = 0x2, ROMFS = 0x3 };
+
+struct NCASectionHeaderBlock {
+    INSERT_PADDING_BYTES(3);
+    NCASectionFilesystemType filesystem_type;
+    u8 crypto_type;
+    INSERT_PADDING_BYTES(3);
+};
+static_assert(sizeof(NCASectionHeaderBlock) == 0x8, "NCASectionHeaderBlock has incorrect size.");
+
+struct PFS0Superblock {
+    NCASectionHeaderBlock header_block;
+    std::array<u8, 0x20> hash;
+    u32_le size;
+    INSERT_PADDING_BYTES(4);
+    u64_le hash_table_offset;
+    u64_le hash_table_size;
+    u64_le pfs0_header_offset;
+    u64_le pfs0_size;
+    INSERT_PADDING_BYTES(432);
+};
+static_assert(sizeof(PFS0Superblock) == 0x200, "PFS0Superblock has incorrect size.");
+
+struct IVFCLevel {
+    u64_le offset;
+    u64_le size;
+    u32_le block_size;
+    u32_le reserved;
+};
+static_assert(sizeof(IVFCLevel) == 0x18, "IVFCLevel has incorrect size.");
+
+struct RomFSSuperblock {
+    NCASectionHeaderBlock header_block;
+    u32_le magic;
+    u32_le magic_number;
+    INSERT_PADDING_BYTES(8);
+    std::array<IVFCLevel, 6> levels;
+    INSERT_PADDING_BYTES(64);
+};
+static_assert(sizeof(RomFSSuperblock) == 0xE8, "RomFSSuperblock has incorrect size.");
+
+NCA::NCA(VirtualFile file_) : file(file_) {
+    if (sizeof(NCAHeader) != file->ReadObject(&header))
+        LOG_CRITICAL(Loader, "File reader errored out during header read.");
+
+    if (!IsValidNCA(header)) {
+        status = Loader::ResultStatus::ErrorInvalidFormat;
+        return;
+    }
+
+    std::ptrdiff_t number_sections =
+        std::count_if(std::begin(header.section_tables), std::end(header.section_tables),
+                      [](NCASectionTableEntry entry) { return entry.media_offset > 0; });
+
+    for (std::ptrdiff_t i = 0; i < number_sections; ++i) {
+        // Seek to beginning of this section.
+        NCASectionHeaderBlock block{};
+        if (sizeof(NCASectionHeaderBlock) !=
+            file->ReadObject(&block, SECTION_HEADER_OFFSET + i * SECTION_HEADER_SIZE))
+            LOG_CRITICAL(Loader, "File reader errored out during header read.");
+
+        if (block.filesystem_type == NCASectionFilesystemType::ROMFS) {
+            RomFSSuperblock sb{};
+            if (sizeof(RomFSSuperblock) !=
+                file->ReadObject(&sb, SECTION_HEADER_OFFSET + i * SECTION_HEADER_SIZE))
+                LOG_CRITICAL(Loader, "File reader errored out during header read.");
+
+            const size_t romfs_offset =
+                header.section_tables[i].media_offset * MEDIA_OFFSET_MULTIPLIER +
+                sb.levels[IVFC_MAX_LEVEL - 1].offset;
+            const size_t romfs_size = sb.levels[IVFC_MAX_LEVEL - 1].size;
+            files.emplace_back(std::make_shared<OffsetVfsFile>(file, romfs_size, romfs_offset));
+            romfs = files.back();
+        } else if (block.filesystem_type == NCASectionFilesystemType::PFS0) {
+            PFS0Superblock sb{};
+            // Seek back to beginning of this section.
+            if (sizeof(PFS0Superblock) !=
+                file->ReadObject(&sb, SECTION_HEADER_OFFSET + i * SECTION_HEADER_SIZE))
+                LOG_CRITICAL(Loader, "File reader errored out during header read.");
+
+            u64 offset = (static_cast<u64>(header.section_tables[i].media_offset) *
+                          MEDIA_OFFSET_MULTIPLIER) +
+                         sb.pfs0_header_offset;
+            u64 size = MEDIA_OFFSET_MULTIPLIER * (header.section_tables[i].media_end_offset -
+                                                  header.section_tables[i].media_offset);
+            auto npfs = std::make_shared<PartitionFilesystem>(
+                std::make_shared<OffsetVfsFile>(file, size, offset));
+
+            if (npfs->GetStatus() == Loader::ResultStatus::Success) {
+                dirs.emplace_back(npfs);
+                if (IsDirectoryExeFS(dirs.back()))
+                    exefs = dirs.back();
+            }
+        }
+    }
+
+    status = Loader::ResultStatus::Success;
+}
+
+Loader::ResultStatus NCA::GetStatus() const {
+    return status;
+}
+
+std::vector<std::shared_ptr<VfsFile>> NCA::GetFiles() const {
+    if (status != Loader::ResultStatus::Success)
+        return {};
+    return files;
+}
+
+std::vector<std::shared_ptr<VfsDirectory>> NCA::GetSubdirectories() const {
+    if (status != Loader::ResultStatus::Success)
+        return {};
+    return dirs;
+}
+
+std::string NCA::GetName() const {
+    return file->GetName();
+}
+
+std::shared_ptr<VfsDirectory> NCA::GetParentDirectory() const {
+    return file->GetContainingDirectory();
+}
+
+NCAContentType NCA::GetType() const {
+    return header.content_type;
+}
+
+u64 NCA::GetTitleId() const {
+    if (status != Loader::ResultStatus::Success)
+        return {};
+    return header.title_id;
+}
+
+VirtualFile NCA::GetRomFS() const {
+    return romfs;
+}
+
+VirtualDir NCA::GetExeFS() const {
+    return exefs;
+}
+
+bool NCA::ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) {
+    return false;
+}
+} // namespace FileSys
diff --git a/src/core/file_sys/content_archive.h b/src/core/file_sys/content_archive.h
new file mode 100644
index 000000000..eb4ca1c18
--- /dev/null
+++ b/src/core/file_sys/content_archive.h
@@ -0,0 +1,89 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+#include "common/swap.h"
+#include "core/file_sys/partition_filesystem.h"
+
+namespace FileSys {
+
+enum class NCAContentType : u8 { Program = 0, Meta = 1, Control = 2, Manual = 3, Data = 4 };
+
+struct NCASectionTableEntry {
+    u32_le media_offset;
+    u32_le media_end_offset;
+    INSERT_PADDING_BYTES(0x8);
+};
+static_assert(sizeof(NCASectionTableEntry) == 0x10, "NCASectionTableEntry has incorrect size.");
+
+struct NCAHeader {
+    std::array<u8, 0x100> rsa_signature_1;
+    std::array<u8, 0x100> rsa_signature_2;
+    u32_le magic;
+    u8 is_system;
+    NCAContentType content_type;
+    u8 crypto_type;
+    u8 key_index;
+    u64_le size;
+    u64_le title_id;
+    INSERT_PADDING_BYTES(0x4);
+    u32_le sdk_version;
+    u8 crypto_type_2;
+    INSERT_PADDING_BYTES(15);
+    std::array<u8, 0x10> rights_id;
+    std::array<NCASectionTableEntry, 0x4> section_tables;
+    std::array<std::array<u8, 0x20>, 0x4> hash_tables;
+    std::array<std::array<u8, 0x10>, 0x4> key_area;
+    INSERT_PADDING_BYTES(0xC0);
+};
+static_assert(sizeof(NCAHeader) == 0x400, "NCAHeader has incorrect size.");
+
+static bool IsDirectoryExeFS(std::shared_ptr<FileSys::VfsDirectory> pfs) {
+    // According to switchbrew, an exefs must only contain these two files:
+    return pfs->GetFile("main") != nullptr && pfs->GetFile("main.npdm") != nullptr;
+}
+
+static bool IsValidNCA(const NCAHeader& header) {
+    return header.magic == Common::MakeMagic('N', 'C', 'A', '2') ||
+           header.magic == Common::MakeMagic('N', 'C', 'A', '3');
+}
+
+// An implementation of VfsDirectory that represents a Nintendo Content Archive (NCA) conatiner.
+// After construction, use GetStatus to determine if the file is valid and ready to be used.
+class NCA : public ReadOnlyVfsDirectory {
+public:
+    explicit NCA(VirtualFile file);
+    Loader::ResultStatus GetStatus() const;
+
+    std::vector<std::shared_ptr<VfsFile>> GetFiles() const override;
+    std::vector<std::shared_ptr<VfsDirectory>> GetSubdirectories() const override;
+    std::string GetName() const override;
+    std::shared_ptr<VfsDirectory> GetParentDirectory() const override;
+
+    NCAContentType GetType() const;
+    u64 GetTitleId() const;
+
+    VirtualFile GetRomFS() const;
+    VirtualDir GetExeFS() const;
+
+protected:
+    bool ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) override;
+
+private:
+    std::vector<VirtualDir> dirs;
+    std::vector<VirtualFile> files;
+
+    VirtualFile romfs = nullptr;
+    VirtualDir exefs = nullptr;
+    VirtualFile file;
+
+    NCAHeader header{};
+
+    Loader::ResultStatus status{};
+};
+
+} // namespace FileSys
diff --git a/src/core/file_sys/disk_filesystem.cpp b/src/core/file_sys/disk_filesystem.cpp
deleted file mode 100644
index 8c6f15bb5..000000000
--- a/src/core/file_sys/disk_filesystem.cpp
+++ /dev/null
@@ -1,237 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include <cstring>
-#include <memory>
-#include "common/common_types.h"
-#include "common/logging/log.h"
-#include "core/file_sys/disk_filesystem.h"
-#include "core/file_sys/errors.h"
-
-namespace FileSys {
-
-static std::string ModeFlagsToString(Mode mode) {
-    std::string mode_str;
-    u32 mode_flags = static_cast<u32>(mode);
-
-    // Calculate the correct open mode for the file.
-    if ((mode_flags & static_cast<u32>(Mode::Read)) &&
-        (mode_flags & static_cast<u32>(Mode::Write))) {
-        if (mode_flags & static_cast<u32>(Mode::Append))
-            mode_str = "a+";
-        else
-            mode_str = "r+";
-    } else {
-        if (mode_flags & static_cast<u32>(Mode::Read))
-            mode_str = "r";
-        else if (mode_flags & static_cast<u32>(Mode::Append))
-            mode_str = "a";
-        else if (mode_flags & static_cast<u32>(Mode::Write))
-            mode_str = "w";
-    }
-
-    mode_str += "b";
-
-    return mode_str;
-}
-
-std::string Disk_FileSystem::GetName() const {
-    return "Disk";
-}
-
-ResultVal<std::unique_ptr<StorageBackend>> Disk_FileSystem::OpenFile(const std::string& path,
-                                                                     Mode mode) const {
-
-    // Calculate the correct open mode for the file.
-    std::string mode_str = ModeFlagsToString(mode);
-
-    std::string full_path = base_directory + path;
-    auto file = std::make_shared<FileUtil::IOFile>(full_path, mode_str.c_str());
-
-    if (!file->IsOpen()) {
-        return ERROR_PATH_NOT_FOUND;
-    }
-
-    return MakeResult<std::unique_ptr<StorageBackend>>(
-        std::make_unique<Disk_Storage>(std::move(file)));
-}
-
-ResultCode Disk_FileSystem::DeleteFile(const std::string& path) const {
-    if (!FileUtil::Exists(path)) {
-        return ERROR_PATH_NOT_FOUND;
-    }
-
-    FileUtil::Delete(path);
-
-    return RESULT_SUCCESS;
-}
-
-ResultCode Disk_FileSystem::RenameFile(const std::string& src_path,
-                                       const std::string& dest_path) const {
-    const std::string full_src_path = base_directory + src_path;
-    const std::string full_dest_path = base_directory + dest_path;
-
-    if (!FileUtil::Exists(full_src_path)) {
-        return ERROR_PATH_NOT_FOUND;
-    }
-    // TODO(wwylele): Use correct error code
-    return FileUtil::Rename(full_src_path, full_dest_path) ? RESULT_SUCCESS : ResultCode(-1);
-}
-
-ResultCode Disk_FileSystem::DeleteDirectory(const Path& path) const {
-    LOG_WARNING(Service_FS, "(STUBBED) called");
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode Disk_FileSystem::DeleteDirectoryRecursively(const Path& path) const {
-    LOG_WARNING(Service_FS, "(STUBBED) called");
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode Disk_FileSystem::CreateFile(const std::string& path, u64 size) const {
-    LOG_WARNING(Service_FS, "(STUBBED) called");
-
-    std::string full_path = base_directory + path;
-    if (size == 0) {
-        FileUtil::CreateEmptyFile(full_path);
-        return RESULT_SUCCESS;
-    }
-
-    FileUtil::IOFile file(full_path, "wb");
-    // Creates a sparse file (or a normal file on filesystems without the concept of sparse files)
-    // We do this by seeking to the right size, then writing a single null byte.
-    if (file.Seek(size - 1, SEEK_SET) && file.WriteBytes("", 1) == 1) {
-        return RESULT_SUCCESS;
-    }
-
-    LOG_ERROR(Service_FS, "Too large file");
-    // TODO(Subv): Find out the correct error code
-    return ResultCode(-1);
-}
-
-ResultCode Disk_FileSystem::CreateDirectory(const std::string& path) const {
-    // TODO(Subv): Perform path validation to prevent escaping the emulator sandbox.
-    std::string full_path = base_directory + path;
-
-    if (FileUtil::CreateDir(full_path)) {
-        return RESULT_SUCCESS;
-    }
-
-    LOG_CRITICAL(Service_FS, "(unreachable) Unknown error creating {}", full_path);
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode Disk_FileSystem::RenameDirectory(const Path& src_path, const Path& dest_path) const {
-    LOG_WARNING(Service_FS, "(STUBBED) called");
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultVal<std::unique_ptr<DirectoryBackend>> Disk_FileSystem::OpenDirectory(
-    const std::string& path) const {
-
-    std::string full_path = base_directory + path;
-
-    if (!FileUtil::IsDirectory(full_path)) {
-        // TODO(Subv): Find the correct error code for this.
-        return ResultCode(-1);
-    }
-
-    auto directory = std::make_unique<Disk_Directory>(full_path);
-    return MakeResult<std::unique_ptr<DirectoryBackend>>(std::move(directory));
-}
-
-u64 Disk_FileSystem::GetFreeSpaceSize() const {
-    LOG_WARNING(Service_FS, "(STUBBED) called");
-    return 0;
-}
-
-ResultVal<FileSys::EntryType> Disk_FileSystem::GetEntryType(const std::string& path) const {
-    std::string full_path = base_directory + path;
-    if (!FileUtil::Exists(full_path)) {
-        return ERROR_PATH_NOT_FOUND;
-    }
-
-    if (FileUtil::IsDirectory(full_path))
-        return MakeResult(EntryType::Directory);
-
-    return MakeResult(EntryType::File);
-}
-
-ResultVal<size_t> Disk_Storage::Read(const u64 offset, const size_t length, u8* buffer) const {
-    LOG_TRACE(Service_FS, "called offset={}, length={}", offset, length);
-    file->Seek(offset, SEEK_SET);
-    return MakeResult<size_t>(file->ReadBytes(buffer, length));
-}
-
-ResultVal<size_t> Disk_Storage::Write(const u64 offset, const size_t length, const bool flush,
-                                      const u8* buffer) const {
-    LOG_WARNING(Service_FS, "(STUBBED) called");
-    file->Seek(offset, SEEK_SET);
-    size_t written = file->WriteBytes(buffer, length);
-    if (flush) {
-        file->Flush();
-    }
-    return MakeResult<size_t>(written);
-}
-
-u64 Disk_Storage::GetSize() const {
-    return file->GetSize();
-}
-
-bool Disk_Storage::SetSize(const u64 size) const {
-    file->Resize(size);
-    file->Flush();
-    return true;
-}
-
-Disk_Directory::Disk_Directory(const std::string& path) {
-    unsigned size = FileUtil::ScanDirectoryTree(path, directory);
-    directory.size = size;
-    directory.isDirectory = true;
-    children_iterator = directory.children.begin();
-}
-
-u64 Disk_Directory::Read(const u64 count, Entry* entries) {
-    u64 entries_read = 0;
-
-    while (entries_read < count && children_iterator != directory.children.cend()) {
-        const FileUtil::FSTEntry& file = *children_iterator;
-        const std::string& filename = file.virtualName;
-        Entry& entry = entries[entries_read];
-
-        LOG_TRACE(Service_FS, "File {}: size={} dir={}", filename, file.size, file.isDirectory);
-
-        // TODO(Link Mauve): use a proper conversion to UTF-16.
-        for (size_t j = 0; j < FILENAME_LENGTH; ++j) {
-            entry.filename[j] = filename[j];
-            if (!filename[j])
-                break;
-        }
-
-        if (file.isDirectory) {
-            entry.file_size = 0;
-            entry.type = EntryType::Directory;
-        } else {
-            entry.file_size = file.size;
-            entry.type = EntryType::File;
-        }
-
-        ++entries_read;
-        ++children_iterator;
-    }
-    return entries_read;
-}
-
-u64 Disk_Directory::GetEntryCount() const {
-    // We convert the children iterator into a const_iterator to allow template argument deduction
-    // in std::distance.
-    std::vector<FileUtil::FSTEntry>::const_iterator current = children_iterator;
-    return std::distance(current, directory.children.end());
-}
-
-} // namespace FileSys
diff --git a/src/core/file_sys/disk_filesystem.h b/src/core/file_sys/disk_filesystem.h
deleted file mode 100644
index 591e39fda..000000000
--- a/src/core/file_sys/disk_filesystem.h
+++ /dev/null
@@ -1,84 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <cstddef>
-#include <memory>
-#include <string>
-#include "common/common_types.h"
-#include "common/file_util.h"
-#include "core/file_sys/directory.h"
-#include "core/file_sys/filesystem.h"
-#include "core/file_sys/storage.h"
-#include "core/hle/result.h"
-
-namespace FileSys {
-
-class Disk_FileSystem : public FileSystemBackend {
-public:
-    explicit Disk_FileSystem(std::string base_directory)
-        : base_directory(std::move(base_directory)) {}
-
-    std::string GetName() const override;
-
-    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
-                                                        Mode mode) const override;
-    ResultCode DeleteFile(const std::string& path) const override;
-    ResultCode RenameFile(const std::string& src_path, const std::string& dest_path) const override;
-    ResultCode DeleteDirectory(const Path& path) const override;
-    ResultCode DeleteDirectoryRecursively(const Path& path) const override;
-    ResultCode CreateFile(const std::string& path, u64 size) const override;
-    ResultCode CreateDirectory(const std::string& path) const override;
-    ResultCode RenameDirectory(const Path& src_path, const Path& dest_path) const override;
-    ResultVal<std::unique_ptr<DirectoryBackend>> OpenDirectory(
-        const std::string& path) const override;
-    u64 GetFreeSpaceSize() const override;
-    ResultVal<EntryType> GetEntryType(const std::string& path) const override;
-
-protected:
-    std::string base_directory;
-};
-
-class Disk_Storage : public StorageBackend {
-public:
-    explicit Disk_Storage(std::shared_ptr<FileUtil::IOFile> file) : file(std::move(file)) {}
-
-    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
-    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
-    u64 GetSize() const override;
-    bool SetSize(u64 size) const override;
-    bool Close() const override {
-        return false;
-    }
-    void Flush() const override {}
-
-private:
-    std::shared_ptr<FileUtil::IOFile> file;
-};
-
-class Disk_Directory : public DirectoryBackend {
-public:
-    explicit Disk_Directory(const std::string& path);
-
-    ~Disk_Directory() override {
-        Close();
-    }
-
-    u64 Read(const u64 count, Entry* entries) override;
-    u64 GetEntryCount() const override;
-
-    bool Close() const override {
-        return true;
-    }
-
-protected:
-    FileUtil::FSTEntry directory;
-
-    // We need to remember the last entry we returned, so a subsequent call to Read will continue
-    // from the next one. This iterator will always point to the next unread entry.
-    std::vector<FileUtil::FSTEntry>::iterator children_iterator;
-};
-
-} // namespace FileSys
diff --git a/src/core/file_sys/filesystem.h b/src/core/file_sys/filesystem.h
index 295a3133e..2d925d9e4 100644
--- a/src/core/file_sys/filesystem.h
+++ b/src/core/file_sys/filesystem.h
@@ -66,136 +66,4 @@ 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
diff --git a/src/core/file_sys/partition_filesystem.cpp b/src/core/file_sys/partition_filesystem.cpp
index 46d438aca..15b1fb946 100644
--- a/src/core/file_sys/partition_filesystem.cpp
+++ b/src/core/file_sys/partition_filesystem.cpp
@@ -6,29 +6,30 @@
 #include "common/file_util.h"
 #include "common/logging/log.h"
 #include "core/file_sys/partition_filesystem.h"
+#include "core/file_sys/vfs_offset.h"
 #include "core/loader/loader.h"
 
 namespace FileSys {
 
-Loader::ResultStatus PartitionFilesystem::Load(const std::string& file_path, size_t offset) {
-    FileUtil::IOFile file(file_path, "rb");
-    if (!file.IsOpen())
-        return Loader::ResultStatus::Error;
-
+PartitionFilesystem::PartitionFilesystem(std::shared_ptr<VfsFile> file) {
     // At least be as large as the header
-    if (file.GetSize() < sizeof(Header))
-        return Loader::ResultStatus::Error;
+    if (file->GetSize() < sizeof(Header)) {
+        status = Loader::ResultStatus::Error;
+        return;
+    }
 
-    file.Seek(offset, SEEK_SET);
     // For cartridges, HFSs can get very large, so we need to calculate the size up to
     // the actual content itself instead of just blindly reading in the entire file.
     Header pfs_header;
-    if (!file.ReadBytes(&pfs_header, sizeof(Header)))
-        return Loader::ResultStatus::Error;
+    if (sizeof(Header) != file->ReadObject(&pfs_header)) {
+        status = Loader::ResultStatus::Error;
+        return;
+    }
 
     if (pfs_header.magic != Common::MakeMagic('H', 'F', 'S', '0') &&
         pfs_header.magic != Common::MakeMagic('P', 'F', 'S', '0')) {
-        return Loader::ResultStatus::ErrorInvalidFormat;
+        status = Loader::ResultStatus::ErrorInvalidFormat;
+        return;
     }
 
     bool is_hfs = pfs_header.magic == Common::MakeMagic('H', 'F', 'S', '0');
@@ -38,99 +39,86 @@ Loader::ResultStatus PartitionFilesystem::Load(const std::string& file_path, siz
         sizeof(Header) + (pfs_header.num_entries * entry_size) + pfs_header.strtab_size;
 
     // Actually read in now...
-    file.Seek(offset, SEEK_SET);
-    std::vector<u8> file_data(metadata_size);
-
-    if (!file.ReadBytes(file_data.data(), metadata_size))
-        return Loader::ResultStatus::Error;
+    std::vector<u8> file_data = file->ReadBytes(metadata_size);
 
-    Loader::ResultStatus result = Load(file_data);
-    if (result != Loader::ResultStatus::Success)
-        LOG_ERROR(Service_FS, "Failed to load PFS from file {}!", file_path);
-
-    return result;
-}
+    if (file_data.size() != metadata_size) {
+        status = Loader::ResultStatus::Error;
+        return;
+    }
 
-Loader::ResultStatus PartitionFilesystem::Load(const std::vector<u8>& file_data, size_t offset) {
-    size_t total_size = file_data.size() - offset;
-    if (total_size < sizeof(Header))
-        return Loader::ResultStatus::Error;
+    size_t total_size = file_data.size();
+    if (total_size < sizeof(Header)) {
+        status = Loader::ResultStatus::Error;
+        return;
+    }
 
-    memcpy(&pfs_header, &file_data[offset], sizeof(Header));
+    memcpy(&pfs_header, file_data.data(), sizeof(Header));
     if (pfs_header.magic != Common::MakeMagic('H', 'F', 'S', '0') &&
         pfs_header.magic != Common::MakeMagic('P', 'F', 'S', '0')) {
-        return Loader::ResultStatus::ErrorInvalidFormat;
+        status = Loader::ResultStatus::ErrorInvalidFormat;
+        return;
     }
 
     is_hfs = pfs_header.magic == Common::MakeMagic('H', 'F', 'S', '0');
 
-    size_t entries_offset = offset + sizeof(Header);
-    size_t entry_size = is_hfs ? sizeof(HFSEntry) : sizeof(PFSEntry);
+    size_t entries_offset = sizeof(Header);
     size_t strtab_offset = entries_offset + (pfs_header.num_entries * entry_size);
+    content_offset = strtab_offset + pfs_header.strtab_size;
     for (u16 i = 0; i < pfs_header.num_entries; i++) {
-        FileEntry entry;
+        FSEntry entry;
 
-        memcpy(&entry.fs_entry, &file_data[entries_offset + (i * entry_size)], sizeof(FSEntry));
-        entry.name = std::string(reinterpret_cast<const char*>(
-            &file_data[strtab_offset + entry.fs_entry.strtab_offset]));
-        pfs_entries.push_back(std::move(entry));
-    }
+        memcpy(&entry, &file_data[entries_offset + (i * entry_size)], sizeof(FSEntry));
+        std::string name(
+            reinterpret_cast<const char*>(&file_data[strtab_offset + entry.strtab_offset]));
 
-    content_offset = strtab_offset + pfs_header.strtab_size;
+        pfs_files.emplace_back(
+            std::make_shared<OffsetVfsFile>(file, entry.size, content_offset + entry.offset, name));
+    }
 
-    return Loader::ResultStatus::Success;
+    status = Loader::ResultStatus::Success;
 }
 
-u32 PartitionFilesystem::GetNumEntries() const {
-    return pfs_header.num_entries;
+Loader::ResultStatus PartitionFilesystem::GetStatus() const {
+    return status;
 }
 
-u64 PartitionFilesystem::GetEntryOffset(u32 index) const {
-    if (index > GetNumEntries())
-        return 0;
-
-    return content_offset + pfs_entries[index].fs_entry.offset;
+std::vector<std::shared_ptr<VfsFile>> PartitionFilesystem::GetFiles() const {
+    return pfs_files;
 }
 
-u64 PartitionFilesystem::GetEntrySize(u32 index) const {
-    if (index > GetNumEntries())
-        return 0;
-
-    return pfs_entries[index].fs_entry.size;
+std::vector<std::shared_ptr<VfsDirectory>> PartitionFilesystem::GetSubdirectories() const {
+    return {};
 }
 
-std::string PartitionFilesystem::GetEntryName(u32 index) const {
-    if (index > GetNumEntries())
-        return "";
+std::string PartitionFilesystem::GetName() const {
+    return is_hfs ? "HFS0" : "PFS0";
+}
 
-    return pfs_entries[index].name;
+std::shared_ptr<VfsDirectory> PartitionFilesystem::GetParentDirectory() const {
+    // TODO(DarkLordZach): Add support for nested containers.
+    return nullptr;
 }
 
-u64 PartitionFilesystem::GetFileOffset(const std::string& name) const {
+void PartitionFilesystem::PrintDebugInfo() const {
+    LOG_DEBUG(Service_FS, "Magic:                  {:.4}", pfs_header.magic);
+    LOG_DEBUG(Service_FS, "Files:                  {}", pfs_header.num_entries);
     for (u32 i = 0; i < pfs_header.num_entries; i++) {
-        if (pfs_entries[i].name == name)
-            return content_offset + pfs_entries[i].fs_entry.offset;
+        LOG_DEBUG(Service_FS, " > File {}:              {} (0x{:X} bytes, at 0x{:X})", i,
+                  pfs_files[i]->GetName(), pfs_files[i]->GetSize(),
+                  dynamic_cast<OffsetVfsFile*>(pfs_files[i].get())->GetOffset());
     }
-
-    return 0;
 }
 
-u64 PartitionFilesystem::GetFileSize(const std::string& name) const {
-    for (u32 i = 0; i < pfs_header.num_entries; i++) {
-        if (pfs_entries[i].name == name)
-            return pfs_entries[i].fs_entry.size;
-    }
+bool PartitionFilesystem::ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) {
+    auto iter = std::find(pfs_files.begin(), pfs_files.end(), file);
+    if (iter == pfs_files.end())
+        return false;
 
-    return 0;
-}
+    pfs_files[iter - pfs_files.begin()] = pfs_files.back();
+    pfs_files.pop_back();
 
-void PartitionFilesystem::Print() const {
-    LOG_DEBUG(Service_FS, "Magic:                  {}", pfs_header.magic);
-    LOG_DEBUG(Service_FS, "Files:                  {}", pfs_header.num_entries);
-    for (u32 i = 0; i < pfs_header.num_entries; i++) {
-        LOG_DEBUG(Service_FS, " > File {}:              {} (0x{:X} bytes, at 0x{:X})", i,
-                  pfs_entries[i].name.c_str(), pfs_entries[i].fs_entry.size,
-                  GetFileOffset(pfs_entries[i].name));
-    }
+    pfs_dirs.emplace_back(dir);
+
+    return true;
 }
 } // namespace FileSys
diff --git a/src/core/file_sys/partition_filesystem.h b/src/core/file_sys/partition_filesystem.h
index 9c5810cf1..9656b40bf 100644
--- a/src/core/file_sys/partition_filesystem.h
+++ b/src/core/file_sys/partition_filesystem.h
@@ -10,6 +10,7 @@
 #include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
+#include "core/file_sys/vfs.h"
 
 namespace Loader {
 enum class ResultStatus;
@@ -21,19 +22,19 @@ namespace FileSys {
  * Helper which implements an interface to parse PFS/HFS filesystems.
  * Data can either be loaded from a file path or data with an offset into it.
  */
-class PartitionFilesystem {
+class PartitionFilesystem : public ReadOnlyVfsDirectory {
 public:
-    Loader::ResultStatus Load(const std::string& file_path, size_t offset = 0);
-    Loader::ResultStatus Load(const std::vector<u8>& file_data, size_t offset = 0);
+    explicit PartitionFilesystem(std::shared_ptr<VfsFile> file);
+    Loader::ResultStatus GetStatus() const;
 
-    u32 GetNumEntries() const;
-    u64 GetEntryOffset(u32 index) const;
-    u64 GetEntrySize(u32 index) const;
-    std::string GetEntryName(u32 index) const;
-    u64 GetFileOffset(const std::string& name) const;
-    u64 GetFileSize(const std::string& name) const;
+    std::vector<std::shared_ptr<VfsFile>> GetFiles() const override;
+    std::vector<std::shared_ptr<VfsDirectory>> GetSubdirectories() const override;
+    std::string GetName() const override;
+    std::shared_ptr<VfsDirectory> GetParentDirectory() const override;
+    void PrintDebugInfo() const;
 
-    void Print() const;
+protected:
+    bool ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) override;
 
 private:
     struct Header {
@@ -72,16 +73,14 @@ private:
 
 #pragma pack(pop)
 
-    struct FileEntry {
-        FSEntry fs_entry;
-        std::string name;
-    };
+    Loader::ResultStatus status;
 
     Header pfs_header;
     bool is_hfs;
     size_t content_offset;
 
-    std::vector<FileEntry> pfs_entries;
+    std::vector<VirtualFile> pfs_files;
+    std::vector<VirtualDir> pfs_dirs;
 };
 
 } // namespace FileSys
diff --git a/src/core/file_sys/program_metadata.cpp b/src/core/file_sys/program_metadata.cpp
index 226811115..63d4b6e4f 100644
--- a/src/core/file_sys/program_metadata.cpp
+++ b/src/core/file_sys/program_metadata.cpp
@@ -9,40 +9,29 @@
 
 namespace FileSys {
 
-Loader::ResultStatus ProgramMetadata::Load(const std::string& file_path) {
-    FileUtil::IOFile file(file_path, "rb");
-    if (!file.IsOpen())
+Loader::ResultStatus ProgramMetadata::Load(VirtualFile file) {
+    size_t total_size = static_cast<size_t>(file->GetSize());
+    if (total_size < sizeof(Header))
         return Loader::ResultStatus::Error;
 
-    std::vector<u8> file_data(file.GetSize());
-
-    if (!file.ReadBytes(file_data.data(), file_data.size()))
+    // TODO(DarkLordZach): Use ReadObject when Header/AcidHeader becomes trivially copyable.
+    std::vector<u8> npdm_header_data = file->ReadBytes(sizeof(Header));
+    if (sizeof(Header) != npdm_header_data.size())
         return Loader::ResultStatus::Error;
+    std::memcpy(&npdm_header, npdm_header_data.data(), sizeof(Header));
 
-    Loader::ResultStatus result = Load(file_data);
-    if (result != Loader::ResultStatus::Success)
-        LOG_ERROR(Service_FS, "Failed to load NPDM from file {}!", file_path);
-
-    return result;
-}
-
-Loader::ResultStatus ProgramMetadata::Load(const std::vector<u8> file_data, size_t offset) {
-    size_t total_size = static_cast<size_t>(file_data.size() - offset);
-    if (total_size < sizeof(Header))
+    std::vector<u8> acid_header_data = file->ReadBytes(sizeof(AcidHeader), npdm_header.acid_offset);
+    if (sizeof(AcidHeader) != acid_header_data.size())
         return Loader::ResultStatus::Error;
+    std::memcpy(&acid_header, acid_header_data.data(), sizeof(AcidHeader));
 
-    size_t header_offset = offset;
-    memcpy(&npdm_header, &file_data[offset], sizeof(Header));
-
-    size_t aci_offset = header_offset + npdm_header.aci_offset;
-    size_t acid_offset = header_offset + npdm_header.acid_offset;
-    memcpy(&aci_header, &file_data[aci_offset], sizeof(AciHeader));
-    memcpy(&acid_header, &file_data[acid_offset], sizeof(AcidHeader));
+    if (sizeof(AciHeader) != file->ReadObject(&aci_header, npdm_header.aci_offset))
+        return Loader::ResultStatus::Error;
 
-    size_t fac_offset = acid_offset + acid_header.fac_offset;
-    size_t fah_offset = aci_offset + aci_header.fah_offset;
-    memcpy(&acid_file_access, &file_data[fac_offset], sizeof(FileAccessControl));
-    memcpy(&aci_file_access, &file_data[fah_offset], sizeof(FileAccessHeader));
+    if (sizeof(FileAccessControl) != file->ReadObject(&acid_file_access, acid_header.fac_offset))
+        return Loader::ResultStatus::Error;
+    if (sizeof(FileAccessHeader) != file->ReadObject(&aci_file_access, aci_header.fah_offset))
+        return Loader::ResultStatus::Error;
 
     return Loader::ResultStatus::Success;
 }
diff --git a/src/core/file_sys/program_metadata.h b/src/core/file_sys/program_metadata.h
index b80a08485..06a7315db 100644
--- a/src/core/file_sys/program_metadata.h
+++ b/src/core/file_sys/program_metadata.h
@@ -10,6 +10,7 @@
 #include "common/bit_field.h"
 #include "common/common_types.h"
 #include "common/swap.h"
+#include "partition_filesystem.h"
 
 namespace Loader {
 enum class ResultStatus;
@@ -37,8 +38,7 @@ enum class ProgramFilePermission : u64 {
  */
 class ProgramMetadata {
 public:
-    Loader::ResultStatus Load(const std::string& file_path);
-    Loader::ResultStatus Load(const std::vector<u8> file_data, size_t offset = 0);
+    Loader::ResultStatus Load(VirtualFile file);
 
     bool Is64BitProgram() const;
     ProgramAddressSpaceType GetAddressSpaceType() const;
@@ -51,6 +51,7 @@ public:
     void Print() const;
 
 private:
+    // TODO(DarkLordZach): BitField is not trivially copyable.
     struct Header {
         std::array<char, 4> magic;
         std::array<u8, 8> reserved;
@@ -77,6 +78,7 @@ private:
 
     static_assert(sizeof(Header) == 0x80, "NPDM header structure size is wrong");
 
+    // TODO(DarkLordZach): BitField is not trivially copyable.
     struct AcidHeader {
         std::array<u8, 0x100> signature;
         std::array<u8, 0x100> nca_modulus;
diff --git a/src/core/file_sys/romfs_factory.cpp b/src/core/file_sys/romfs_factory.cpp
deleted file mode 100644
index 84ae0d99b..000000000
--- a/src/core/file_sys/romfs_factory.cpp
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include <algorithm>
-#include <memory>
-#include "common/common_types.h"
-#include "common/logging/log.h"
-#include "core/file_sys/romfs_factory.h"
-#include "core/file_sys/romfs_filesystem.h"
-
-namespace FileSys {
-
-RomFS_Factory::RomFS_Factory(Loader::AppLoader& app_loader) {
-    // Load the RomFS from the app
-    if (Loader::ResultStatus::Success != app_loader.ReadRomFS(romfs_file, data_offset, data_size)) {
-        LOG_ERROR(Service_FS, "Unable to read RomFS!");
-    }
-}
-
-ResultVal<std::unique_ptr<FileSystemBackend>> RomFS_Factory::Open(const Path& path) {
-    auto archive = std::make_unique<RomFS_FileSystem>(romfs_file, data_offset, data_size);
-    return MakeResult<std::unique_ptr<FileSystemBackend>>(std::move(archive));
-}
-
-ResultCode RomFS_Factory::Format(const Path& path) {
-    LOG_ERROR(Service_FS, "Unimplemented Format archive {}", GetName());
-    // TODO(bunnei): Find the right error code for this
-    return ResultCode(-1);
-}
-
-ResultVal<ArchiveFormatInfo> RomFS_Factory::GetFormatInfo(const Path& path) const {
-    LOG_ERROR(Service_FS, "Unimplemented GetFormatInfo archive {}", GetName());
-    // TODO(bunnei): Find the right error code for this
-    return ResultCode(-1);
-}
-
-} // namespace FileSys
diff --git a/src/core/file_sys/romfs_factory.h b/src/core/file_sys/romfs_factory.h
deleted file mode 100644
index e0698e642..000000000
--- a/src/core/file_sys/romfs_factory.h
+++ /dev/null
@@ -1,35 +0,0 @@
-// 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 <vector>
-#include "common/common_types.h"
-#include "core/file_sys/filesystem.h"
-#include "core/hle/result.h"
-#include "core/loader/loader.h"
-
-namespace FileSys {
-
-/// File system interface to the RomFS archive
-class RomFS_Factory final : public FileSystemFactory {
-public:
-    explicit RomFS_Factory(Loader::AppLoader& app_loader);
-
-    std::string GetName() const override {
-        return "ArchiveFactory_RomFS";
-    }
-    ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) override;
-    ResultCode Format(const Path& path) override;
-    ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
-
-private:
-    std::shared_ptr<FileUtil::IOFile> romfs_file;
-    u64 data_offset;
-    u64 data_size;
-};
-
-} // namespace FileSys
diff --git a/src/core/file_sys/romfs_filesystem.cpp b/src/core/file_sys/romfs_filesystem.cpp
deleted file mode 100644
index 83162622b..000000000
--- a/src/core/file_sys/romfs_filesystem.cpp
+++ /dev/null
@@ -1,110 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include <cstring>
-#include <memory>
-#include "common/common_types.h"
-#include "common/logging/log.h"
-#include "core/file_sys/romfs_filesystem.h"
-
-namespace FileSys {
-
-std::string RomFS_FileSystem::GetName() const {
-    return "RomFS";
-}
-
-ResultVal<std::unique_ptr<StorageBackend>> RomFS_FileSystem::OpenFile(const std::string& path,
-                                                                      Mode mode) const {
-    return MakeResult<std::unique_ptr<StorageBackend>>(
-        std::make_unique<RomFS_Storage>(romfs_file, data_offset, data_size));
-}
-
-ResultCode RomFS_FileSystem::DeleteFile(const std::string& path) const {
-    LOG_CRITICAL(Service_FS, "Attempted to delete a file from an ROMFS archive ({}).", GetName());
-    // TODO(bunnei): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode RomFS_FileSystem::RenameFile(const std::string& src_path,
-                                        const std::string& dest_path) const {
-    LOG_CRITICAL(Service_FS, "Attempted to rename a file within an ROMFS archive ({}).", GetName());
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode RomFS_FileSystem::DeleteDirectory(const Path& path) const {
-    LOG_CRITICAL(Service_FS, "Attempted to delete a directory from an ROMFS archive ({}).",
-                 GetName());
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode RomFS_FileSystem::DeleteDirectoryRecursively(const Path& path) const {
-    LOG_CRITICAL(Service_FS, "Attempted to delete a directory from an ROMFS archive ({}).",
-                 GetName());
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode RomFS_FileSystem::CreateFile(const std::string& path, u64 size) const {
-    LOG_CRITICAL(Service_FS, "Attempted to create a file in an ROMFS archive ({}).", GetName());
-    // TODO(bunnei): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode RomFS_FileSystem::CreateDirectory(const std::string& path) const {
-    LOG_CRITICAL(Service_FS, "Attempted to create a directory in an ROMFS archive ({}).",
-                 GetName());
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultCode RomFS_FileSystem::RenameDirectory(const Path& src_path, const Path& dest_path) const {
-    LOG_CRITICAL(Service_FS, "Attempted to rename a file within an ROMFS archive ({}).", GetName());
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultVal<std::unique_ptr<DirectoryBackend>> RomFS_FileSystem::OpenDirectory(
-    const std::string& path) const {
-    LOG_WARNING(Service_FS, "Opening Directory in a ROMFS archive");
-    return MakeResult<std::unique_ptr<DirectoryBackend>>(std::make_unique<ROMFSDirectory>());
-}
-
-u64 RomFS_FileSystem::GetFreeSpaceSize() const {
-    LOG_WARNING(Service_FS, "Attempted to get the free space in an ROMFS archive");
-    return 0;
-}
-
-ResultVal<FileSys::EntryType> RomFS_FileSystem::GetEntryType(const std::string& path) const {
-    LOG_CRITICAL(Service_FS, "Called within an ROMFS archive (path {}).", path);
-    // TODO(wwylele): Use correct error code
-    return ResultCode(-1);
-}
-
-ResultVal<size_t> RomFS_Storage::Read(const u64 offset, const size_t length, u8* buffer) const {
-    LOG_TRACE(Service_FS, "called offset={}, length={}", offset, length);
-    romfs_file->Seek(data_offset + offset, SEEK_SET);
-    size_t read_length = (size_t)std::min((u64)length, data_size - offset);
-
-    return MakeResult<size_t>(romfs_file->ReadBytes(buffer, read_length));
-}
-
-ResultVal<size_t> RomFS_Storage::Write(const u64 offset, const size_t length, const bool flush,
-                                       const u8* buffer) const {
-    LOG_ERROR(Service_FS, "Attempted to write to ROMFS file");
-    // TODO(Subv): Find error code
-    return MakeResult<size_t>(0);
-}
-
-u64 RomFS_Storage::GetSize() const {
-    return data_size;
-}
-
-bool RomFS_Storage::SetSize(const u64 size) const {
-    LOG_ERROR(Service_FS, "Attempted to set the size of an ROMFS file");
-    return false;
-}
-
-} // namespace FileSys
diff --git a/src/core/file_sys/romfs_filesystem.h b/src/core/file_sys/romfs_filesystem.h
deleted file mode 100644
index ba9d85823..000000000
--- a/src/core/file_sys/romfs_filesystem.h
+++ /dev/null
@@ -1,85 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <cstddef>
-#include <memory>
-#include <string>
-#include <vector>
-#include "common/common_types.h"
-#include "common/file_util.h"
-#include "core/file_sys/directory.h"
-#include "core/file_sys/filesystem.h"
-#include "core/file_sys/storage.h"
-#include "core/hle/result.h"
-
-namespace FileSys {
-
-/**
- * Helper which implements an interface to deal with Switch .istorage ROMFS images used in some
- * archives This should be subclassed by concrete archive types, which will provide the input data
- * (load the raw ROMFS archive) and override any required methods
- */
-class RomFS_FileSystem : public FileSystemBackend {
-public:
-    RomFS_FileSystem(std::shared_ptr<FileUtil::IOFile> file, u64 offset, u64 size)
-        : romfs_file(file), data_offset(offset), data_size(size) {}
-
-    std::string GetName() const override;
-
-    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
-                                                        Mode mode) const override;
-    ResultCode DeleteFile(const std::string& path) const override;
-    ResultCode RenameFile(const std::string& src_path, const std::string& dest_path) const override;
-    ResultCode DeleteDirectory(const Path& path) const override;
-    ResultCode DeleteDirectoryRecursively(const Path& path) const override;
-    ResultCode CreateFile(const std::string& path, u64 size) const override;
-    ResultCode CreateDirectory(const std::string& path) const override;
-    ResultCode RenameDirectory(const Path& src_path, const Path& dest_path) const override;
-    ResultVal<std::unique_ptr<DirectoryBackend>> OpenDirectory(
-        const std::string& path) const override;
-    u64 GetFreeSpaceSize() const override;
-    ResultVal<EntryType> GetEntryType(const std::string& path) const override;
-
-protected:
-    std::shared_ptr<FileUtil::IOFile> romfs_file;
-    u64 data_offset;
-    u64 data_size;
-};
-
-class RomFS_Storage : public StorageBackend {
-public:
-    RomFS_Storage(std::shared_ptr<FileUtil::IOFile> file, u64 offset, u64 size)
-        : romfs_file(file), data_offset(offset), data_size(size) {}
-
-    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
-    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
-    u64 GetSize() const override;
-    bool SetSize(u64 size) const override;
-    bool Close() const override {
-        return false;
-    }
-    void Flush() const override {}
-
-private:
-    std::shared_ptr<FileUtil::IOFile> romfs_file;
-    u64 data_offset;
-    u64 data_size;
-};
-
-class ROMFSDirectory : public DirectoryBackend {
-public:
-    u64 Read(const u64 count, Entry* entries) override {
-        return 0;
-    }
-    u64 GetEntryCount() const override {
-        return 0;
-    }
-    bool Close() const override {
-        return false;
-    }
-};
-
-} // namespace FileSys
diff --git a/src/core/file_sys/savedata_factory.cpp b/src/core/file_sys/savedata_factory.cpp
deleted file mode 100644
index d78baf9c3..000000000
--- a/src/core/file_sys/savedata_factory.cpp
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include <memory>
-#include "common/common_types.h"
-#include "common/logging/log.h"
-#include "core/core.h"
-#include "core/file_sys/disk_filesystem.h"
-#include "core/file_sys/savedata_factory.h"
-#include "core/hle/kernel/process.h"
-
-namespace FileSys {
-
-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) {
-    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) {
-    LOG_WARNING(Service_FS, "Format archive {}", GetName());
-    // 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 {}", GetName());
-    // TODO(bunnei): Find the right error code for this
-    return ResultCode(-1);
-}
-
-std::string SaveData_Factory::GetFullPath() const {
-    u64 title_id = Core::CurrentProcess()->program_id;
-    // TODO(Subv): Somehow obtain this value.
-    u32 user = 0;
-    return fmt::format("{}save/{:016X}/{:08X}/", nand_directory, title_id, user);
-}
-
-} // namespace FileSys
diff --git a/src/core/file_sys/savedata_factory.h b/src/core/file_sys/savedata_factory.h
deleted file mode 100644
index 73a42aab6..000000000
--- a/src/core/file_sys/savedata_factory.h
+++ /dev/null
@@ -1,33 +0,0 @@
-// 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 "common/common_types.h"
-#include "core/file_sys/filesystem.h"
-#include "core/hle/result.h"
-
-namespace FileSys {
-
-/// File system interface to the SaveData archive
-class SaveData_Factory final : public FileSystemFactory {
-public:
-    explicit SaveData_Factory(std::string nand_directory);
-
-    std::string GetName() const override {
-        return "SaveData_Factory";
-    }
-    ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) 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
diff --git a/src/core/file_sys/sdmc_factory.cpp b/src/core/file_sys/sdmc_factory.cpp
deleted file mode 100644
index 2e5ffb764..000000000
--- a/src/core/file_sys/sdmc_factory.cpp
+++ /dev/null
@@ -1,39 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include <memory>
-#include "common/common_types.h"
-#include "common/logging/log.h"
-#include "common/string_util.h"
-#include "core/core.h"
-#include "core/file_sys/disk_filesystem.h"
-#include "core/file_sys/sdmc_factory.h"
-
-namespace FileSys {
-
-SDMC_Factory::SDMC_Factory(std::string sd_directory) : sd_directory(std::move(sd_directory)) {}
-
-ResultVal<std::unique_ptr<FileSystemBackend>> SDMC_Factory::Open(const Path& path) {
-    // Create the SD Card directory if it doesn't already exist.
-    if (!FileUtil::IsDirectory(sd_directory)) {
-        FileUtil::CreateFullPath(sd_directory);
-    }
-
-    auto archive = std::make_unique<Disk_FileSystem>(sd_directory);
-    return MakeResult<std::unique_ptr<FileSystemBackend>>(std::move(archive));
-}
-
-ResultCode SDMC_Factory::Format(const Path& path) {
-    LOG_ERROR(Service_FS, "Unimplemented Format archive {}", GetName());
-    // TODO(Subv): Find the right error code for this
-    return ResultCode(-1);
-}
-
-ResultVal<ArchiveFormatInfo> SDMC_Factory::GetFormatInfo(const Path& path) const {
-    LOG_ERROR(Service_FS, "Unimplemented GetFormatInfo archive {}", GetName());
-    // TODO(bunnei): Find the right error code for this
-    return ResultCode(-1);
-}
-
-} // namespace FileSys
diff --git a/src/core/file_sys/sdmc_factory.h b/src/core/file_sys/sdmc_factory.h
deleted file mode 100644
index 93becda25..000000000
--- a/src/core/file_sys/sdmc_factory.h
+++ /dev/null
@@ -1,31 +0,0 @@
-// 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 "common/common_types.h"
-#include "core/file_sys/filesystem.h"
-#include "core/hle/result.h"
-
-namespace FileSys {
-
-/// File system interface to the SDCard archive
-class SDMC_Factory final : public FileSystemFactory {
-public:
-    explicit SDMC_Factory(std::string sd_directory);
-
-    std::string GetName() const override {
-        return "SDMC_Factory";
-    }
-    ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) override;
-    ResultCode Format(const Path& path) override;
-    ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
-
-private:
-    std::string sd_directory;
-};
-
-} // namespace FileSys
diff --git a/src/core/file_sys/vfs.cpp b/src/core/file_sys/vfs.cpp
new file mode 100644
index 000000000..c99071d6a
--- /dev/null
+++ b/src/core/file_sys/vfs.cpp
@@ -0,0 +1,187 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <numeric>
+#include "common/file_util.h"
+#include "core/file_sys/vfs.h"
+
+namespace FileSys {
+
+VfsFile::~VfsFile() = default;
+
+std::string VfsFile::GetExtension() const {
+    return FileUtil::GetExtensionFromFilename(GetName());
+}
+
+VfsDirectory::~VfsDirectory() = default;
+
+boost::optional<u8> VfsFile::ReadByte(size_t offset) const {
+    u8 out{};
+    size_t size = Read(&out, 1, offset);
+    if (size == 1)
+        return out;
+
+    return boost::none;
+}
+
+std::vector<u8> VfsFile::ReadBytes(size_t size, size_t offset) const {
+    std::vector<u8> out(size);
+    size_t read_size = Read(out.data(), size, offset);
+    out.resize(read_size);
+    return out;
+}
+
+std::vector<u8> VfsFile::ReadAllBytes() const {
+    return ReadBytes(GetSize());
+}
+
+bool VfsFile::WriteByte(u8 data, size_t offset) {
+    return Write(&data, 1, offset) == 1;
+}
+
+size_t VfsFile::WriteBytes(std::vector<u8> data, size_t offset) {
+    return Write(data.data(), data.size(), offset);
+}
+
+std::shared_ptr<VfsFile> VfsDirectory::GetFileRelative(const std::string& path) const {
+    auto vec = FileUtil::SplitPathComponents(path);
+    vec.erase(std::remove_if(vec.begin(), vec.end(), [](const auto& str) { return str.empty(); }),
+              vec.end());
+    if (vec.empty())
+        return nullptr;
+    if (vec.size() == 1)
+        return GetFile(vec[0]);
+    auto dir = GetSubdirectory(vec[0]);
+    for (size_t i = 1; i < vec.size() - 1; ++i) {
+        if (dir == nullptr)
+            return nullptr;
+        dir = dir->GetSubdirectory(vec[i]);
+    }
+    if (dir == nullptr)
+        return nullptr;
+    return dir->GetFile(vec.back());
+}
+
+std::shared_ptr<VfsFile> VfsDirectory::GetFileAbsolute(const std::string& path) const {
+    if (IsRoot())
+        return GetFileRelative(path);
+
+    return GetParentDirectory()->GetFileAbsolute(path);
+}
+
+std::shared_ptr<VfsDirectory> VfsDirectory::GetDirectoryRelative(const std::string& path) const {
+    auto vec = FileUtil::SplitPathComponents(path);
+    vec.erase(std::remove_if(vec.begin(), vec.end(), [](const auto& str) { return str.empty(); }),
+              vec.end());
+    if (vec.empty())
+        // return std::shared_ptr<VfsDirectory>(this);
+        return nullptr;
+    auto dir = GetSubdirectory(vec[0]);
+    for (size_t i = 1; i < vec.size(); ++i) {
+        dir = dir->GetSubdirectory(vec[i]);
+    }
+    return dir;
+}
+
+std::shared_ptr<VfsDirectory> VfsDirectory::GetDirectoryAbsolute(const std::string& path) const {
+    if (IsRoot())
+        return GetDirectoryRelative(path);
+
+    return GetParentDirectory()->GetDirectoryAbsolute(path);
+}
+
+std::shared_ptr<VfsFile> VfsDirectory::GetFile(const std::string& name) const {
+    const auto& files = GetFiles();
+    const auto iter = std::find_if(files.begin(), files.end(),
+                                   [&name](const auto& file1) { return name == file1->GetName(); });
+    return iter == files.end() ? nullptr : *iter;
+}
+
+std::shared_ptr<VfsDirectory> VfsDirectory::GetSubdirectory(const std::string& name) const {
+    const auto& subs = GetSubdirectories();
+    const auto iter = std::find_if(subs.begin(), subs.end(),
+                                   [&name](const auto& file1) { return name == file1->GetName(); });
+    return iter == subs.end() ? nullptr : *iter;
+}
+
+bool VfsDirectory::IsRoot() const {
+    return GetParentDirectory() == nullptr;
+}
+
+size_t VfsDirectory::GetSize() const {
+    const auto& files = GetFiles();
+    const auto file_total =
+        std::accumulate(files.begin(), files.end(), 0ull,
+                        [](const auto& f1, const auto& f2) { return f1 + f2->GetSize(); });
+
+    const auto& sub_dir = GetSubdirectories();
+    const auto subdir_total =
+        std::accumulate(sub_dir.begin(), sub_dir.end(), 0ull,
+                        [](const auto& f1, const auto& f2) { return f1 + f2->GetSize(); });
+
+    return file_total + subdir_total;
+}
+
+bool VfsDirectory::DeleteSubdirectoryRecursive(const std::string& name) {
+    auto dir = GetSubdirectory(name);
+    if (dir == nullptr)
+        return false;
+
+    bool success = true;
+    for (const auto& file : dir->GetFiles()) {
+        if (!DeleteFile(file->GetName()))
+            success = false;
+    }
+
+    for (const auto& sdir : dir->GetSubdirectories()) {
+        if (!dir->DeleteSubdirectoryRecursive(sdir->GetName()))
+            success = false;
+    }
+
+    return success;
+}
+
+bool VfsDirectory::Copy(const std::string& src, const std::string& dest) {
+    const auto f1 = GetFile(src);
+    auto f2 = CreateFile(dest);
+    if (f1 == nullptr || f2 == nullptr)
+        return false;
+
+    if (!f2->Resize(f1->GetSize())) {
+        DeleteFile(dest);
+        return false;
+    }
+
+    return f2->WriteBytes(f1->ReadAllBytes()) == f1->GetSize();
+}
+
+bool ReadOnlyVfsDirectory::IsWritable() const {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::IsReadable() const {
+    return true;
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectory::CreateSubdirectory(const std::string& name) {
+    return nullptr;
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectory::CreateFile(const std::string& name) {
+    return nullptr;
+}
+
+bool ReadOnlyVfsDirectory::DeleteSubdirectory(const std::string& name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::DeleteFile(const std::string& name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::Rename(const std::string& name) {
+    return false;
+}
+} // namespace FileSys
diff --git a/src/core/file_sys/vfs.h b/src/core/file_sys/vfs.h
new file mode 100644
index 000000000..0e30991b4
--- /dev/null
+++ b/src/core/file_sys/vfs.h
@@ -0,0 +1,220 @@
+// 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 <type_traits>
+#include <vector>
+#include "boost/optional.hpp"
+#include "common/common_types.h"
+#include "common/file_util.h"
+
+namespace FileSys {
+struct VfsFile;
+struct VfsDirectory;
+
+// Convenience typedefs to use VfsDirectory and VfsFile
+using VirtualDir = std::shared_ptr<FileSys::VfsDirectory>;
+using VirtualFile = std::shared_ptr<FileSys::VfsFile>;
+
+// A class representing a file in an abstract filesystem.
+struct VfsFile : NonCopyable {
+    virtual ~VfsFile();
+
+    // Retrieves the file name.
+    virtual std::string GetName() const = 0;
+    // Retrieves the extension of the file name.
+    virtual std::string GetExtension() const;
+    // Retrieves the size of the file.
+    virtual size_t GetSize() const = 0;
+    // Resizes the file to new_size. Returns whether or not the operation was successful.
+    virtual bool Resize(size_t new_size) = 0;
+    // Gets a pointer to the directory containing this file, returning nullptr if there is none.
+    virtual std::shared_ptr<VfsDirectory> GetContainingDirectory() const = 0;
+
+    // Returns whether or not the file can be written to.
+    virtual bool IsWritable() const = 0;
+    // Returns whether or not the file can be read from.
+    virtual bool IsReadable() const = 0;
+
+    // The primary method of reading from the file. Reads length bytes into data starting at offset
+    // into file. Returns number of bytes successfully read.
+    virtual size_t Read(u8* data, size_t length, size_t offset = 0) const = 0;
+    // The primary method of writing to the file. Writes length bytes from data starting at offset
+    // into file. Returns number of bytes successfully written.
+    virtual size_t Write(const u8* data, size_t length, size_t offset = 0) = 0;
+
+    // Reads exactly one byte at the offset provided, returning boost::none on error.
+    virtual boost::optional<u8> ReadByte(size_t offset = 0) const;
+    // Reads size bytes starting at offset in file into a vector.
+    virtual std::vector<u8> ReadBytes(size_t size, size_t offset = 0) const;
+    // Reads all the bytes from the file into a vector. Equivalent to 'file->Read(file->GetSize(),
+    // 0)'
+    virtual std::vector<u8> ReadAllBytes() const;
+
+    // Reads an array of type T, size number_elements starting at offset.
+    // Returns the number of bytes (sizeof(T)*number_elements) read successfully.
+    template <typename T>
+    size_t ReadArray(T* data, size_t number_elements, size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+
+        return Read(reinterpret_cast<u8*>(data), number_elements * sizeof(T), offset);
+    }
+
+    // Reads size bytes into the memory starting at data starting at offset into the file.
+    // Returns the number of bytes read successfully.
+    template <typename T>
+    size_t ReadBytes(T* data, size_t size, size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Read(reinterpret_cast<u8*>(data), size, offset);
+    }
+
+    // Reads one object of type T starting at offset in file.
+    // Returns the number of bytes read successfully (sizeof(T)).
+    template <typename T>
+    size_t ReadObject(T* data, size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Read(reinterpret_cast<u8*>(data), sizeof(T), offset);
+    }
+
+    // Writes exactly one byte to offset in file and retuns whether or not the byte was written
+    // successfully.
+    virtual bool WriteByte(u8 data, size_t offset = 0);
+    // Writes a vector of bytes to offset in file and returns the number of bytes successfully
+    // written.
+    virtual size_t WriteBytes(std::vector<u8> data, size_t offset = 0);
+
+    // Writes an array of type T, size number_elements to offset in file.
+    // Returns the number of bytes (sizeof(T)*number_elements) written successfully.
+    template <typename T>
+    size_t WriteArray(T* data, size_t number_elements, size_t offset = 0) {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+
+        return Write(data, number_elements * sizeof(T), offset);
+    }
+
+    // Writes size bytes starting at memory location data to offset in file.
+    // Returns the number of bytes written successfully.
+    template <typename T>
+    size_t WriteBytes(T* data, size_t size, size_t offset = 0) {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Write(reinterpret_cast<u8*>(data), size, offset);
+    }
+
+    // Writes one object of type T to offset in file.
+    // Returns the number of bytes written successfully (sizeof(T)).
+    template <typename T>
+    size_t WriteObject(const T& data, size_t offset = 0) {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Write(&data, sizeof(T), offset);
+    }
+
+    // Renames the file to name. Returns whether or not the operation was successsful.
+    virtual bool Rename(const std::string& name) = 0;
+};
+
+// A class representing a directory in an abstract filesystem.
+struct VfsDirectory : NonCopyable {
+    virtual ~VfsDirectory();
+
+    // Retrives the file located at path as if the current directory was root. Returns nullptr if
+    // not found.
+    virtual std::shared_ptr<VfsFile> GetFileRelative(const std::string& path) const;
+    // Calls GetFileRelative(path) on the root of the current directory.
+    virtual std::shared_ptr<VfsFile> GetFileAbsolute(const std::string& path) const;
+
+    // Retrives the directory located at path as if the current directory was root. Returns nullptr
+    // if not found.
+    virtual std::shared_ptr<VfsDirectory> GetDirectoryRelative(const std::string& path) const;
+    // Calls GetDirectoryRelative(path) on the root of the current directory.
+    virtual std::shared_ptr<VfsDirectory> GetDirectoryAbsolute(const std::string& path) const;
+
+    // Returns a vector containing all of the files in this directory.
+    virtual std::vector<std::shared_ptr<VfsFile>> GetFiles() const = 0;
+    // Returns the file with filename matching name. Returns nullptr if directory dosen't have a
+    // file with name.
+    virtual std::shared_ptr<VfsFile> GetFile(const std::string& name) const;
+
+    // Returns a vector containing all of the subdirectories in this directory.
+    virtual std::vector<std::shared_ptr<VfsDirectory>> GetSubdirectories() const = 0;
+    // Returns the directory with name matching name. Returns nullptr if directory dosen't have a
+    // directory with name.
+    virtual std::shared_ptr<VfsDirectory> GetSubdirectory(const std::string& name) const;
+
+    // Returns whether or not the directory can be written to.
+    virtual bool IsWritable() const = 0;
+    // Returns whether of not the directory can be read from.
+    virtual bool IsReadable() const = 0;
+
+    // Returns whether or not the directory is the root of the current file tree.
+    virtual bool IsRoot() const;
+
+    // Returns the name of the directory.
+    virtual std::string GetName() const = 0;
+    // Returns the total size of all files and subdirectories in this directory.
+    virtual size_t GetSize() const;
+    // Returns the parent directory of this directory. Returns nullptr if this directory is root or
+    // has no parent.
+    virtual std::shared_ptr<VfsDirectory> GetParentDirectory() const = 0;
+
+    // Creates a new subdirectory with name name. Returns a pointer to the new directory or nullptr
+    // if the operation failed.
+    virtual std::shared_ptr<VfsDirectory> CreateSubdirectory(const std::string& name) = 0;
+    // Creates a new file with name name. Returns a pointer to the new file or nullptr if the
+    // operation failed.
+    virtual std::shared_ptr<VfsFile> CreateFile(const std::string& name) = 0;
+
+    // Deletes the subdirectory with name and returns true on success.
+    virtual bool DeleteSubdirectory(const std::string& name) = 0;
+    // Deletes all subdirectories and files of subdirectory with name recirsively and then deletes
+    // the subdirectory. Returns true on success.
+    virtual bool DeleteSubdirectoryRecursive(const std::string& name);
+    // Returnes whether or not the file with name name was deleted successfully.
+    virtual bool DeleteFile(const std::string& name) = 0;
+
+    // Returns whether or not this directory was renamed to name.
+    virtual bool Rename(const std::string& name) = 0;
+
+    // Returns whether or not the file with name src was successfully copied to a new file with name
+    // dest.
+    virtual bool Copy(const std::string& src, const std::string& dest);
+
+    // Interprets the file with name file instead as a directory of type directory.
+    // The directory must have a constructor that takes a single argument of type
+    // std::shared_ptr<VfsFile>. Allows to reinterpret container files (i.e NCA, zip, XCI, etc) as a
+    // subdirectory in one call.
+    template <typename Directory>
+    bool InterpretAsDirectory(const std::string& file) {
+        auto file_p = GetFile(file);
+        if (file_p == nullptr)
+            return false;
+        return ReplaceFileWithSubdirectory(file, std::make_shared<Directory>(file_p));
+    }
+
+protected:
+    // Backend for InterpretAsDirectory.
+    // Removes all references to file and adds a reference to dir in the directory's implementation.
+    virtual bool ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) = 0;
+};
+
+// A convenience partial-implementation of VfsDirectory that stubs out methods that should only work
+// if writable. This is to avoid redundant empty methods everywhere.
+struct ReadOnlyVfsDirectory : public VfsDirectory {
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::shared_ptr<VfsDirectory> CreateSubdirectory(const std::string& name) override;
+    std::shared_ptr<VfsFile> CreateFile(const std::string& name) override;
+    bool DeleteSubdirectory(const std::string& name) override;
+    bool DeleteFile(const std::string& name) override;
+    bool Rename(const std::string& name) override;
+};
+} // namespace FileSys
diff --git a/src/core/file_sys/vfs_offset.cpp b/src/core/file_sys/vfs_offset.cpp
new file mode 100644
index 000000000..288499cb5
--- /dev/null
+++ b/src/core/file_sys/vfs_offset.cpp
@@ -0,0 +1,92 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "core/file_sys/vfs_offset.h"
+
+namespace FileSys {
+
+OffsetVfsFile::OffsetVfsFile(std::shared_ptr<VfsFile> file_, size_t size_, size_t offset_,
+                             const std::string& name_)
+    : file(file_), offset(offset_), size(size_), name(name_) {}
+
+std::string OffsetVfsFile::GetName() const {
+    return name.empty() ? file->GetName() : name;
+}
+
+size_t OffsetVfsFile::GetSize() const {
+    return size;
+}
+
+bool OffsetVfsFile::Resize(size_t new_size) {
+    if (offset + new_size < file->GetSize()) {
+        size = new_size;
+    } else {
+        auto res = file->Resize(offset + new_size);
+        if (!res)
+            return false;
+        size = new_size;
+    }
+
+    return true;
+}
+
+std::shared_ptr<VfsDirectory> OffsetVfsFile::GetContainingDirectory() const {
+    return file->GetContainingDirectory();
+}
+
+bool OffsetVfsFile::IsWritable() const {
+    return file->IsWritable();
+}
+
+bool OffsetVfsFile::IsReadable() const {
+    return file->IsReadable();
+}
+
+size_t OffsetVfsFile::Read(u8* data, size_t length, size_t r_offset) const {
+    return file->Read(data, TrimToFit(length, r_offset), offset + r_offset);
+}
+
+size_t OffsetVfsFile::Write(const u8* data, size_t length, size_t r_offset) {
+    return file->Write(data, TrimToFit(length, r_offset), offset + r_offset);
+}
+
+boost::optional<u8> OffsetVfsFile::ReadByte(size_t r_offset) const {
+    if (r_offset < size)
+        return file->ReadByte(offset + r_offset);
+
+    return boost::none;
+}
+
+std::vector<u8> OffsetVfsFile::ReadBytes(size_t r_size, size_t r_offset) const {
+    return file->ReadBytes(TrimToFit(r_size, r_offset), offset + r_offset);
+}
+
+std::vector<u8> OffsetVfsFile::ReadAllBytes() const {
+    return file->ReadBytes(size, offset);
+}
+
+bool OffsetVfsFile::WriteByte(u8 data, size_t r_offset) {
+    if (r_offset < size)
+        return file->WriteByte(data, offset + r_offset);
+
+    return false;
+}
+
+size_t OffsetVfsFile::WriteBytes(std::vector<u8> data, size_t r_offset) {
+    return file->Write(data.data(), TrimToFit(data.size(), r_offset), offset + r_offset);
+}
+
+bool OffsetVfsFile::Rename(const std::string& name) {
+    return file->Rename(name);
+}
+
+size_t OffsetVfsFile::GetOffset() const {
+    return offset;
+}
+
+size_t OffsetVfsFile::TrimToFit(size_t r_size, size_t r_offset) const {
+    return std::max<size_t>(std::min<size_t>(size - r_offset, r_size), 0);
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/vfs_offset.h b/src/core/file_sys/vfs_offset.h
new file mode 100644
index 000000000..adc615b38
--- /dev/null
+++ b/src/core/file_sys/vfs_offset.h
@@ -0,0 +1,46 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/file_sys/vfs.h"
+
+namespace FileSys {
+
+// An implementation of VfsFile that wraps around another VfsFile at a certain offset.
+// Similar to seeking to an offset.
+// If the file is writable, operations that would write past the end of the offset file will expand
+// the size of this wrapper.
+struct OffsetVfsFile : public VfsFile {
+    OffsetVfsFile(std::shared_ptr<VfsFile> file, size_t size, size_t offset = 0,
+                  const std::string& new_name = "");
+
+    std::string GetName() const override;
+    size_t GetSize() const override;
+    bool Resize(size_t new_size) override;
+    std::shared_ptr<VfsDirectory> GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    size_t Read(u8* data, size_t length, size_t offset) const override;
+    size_t Write(const u8* data, size_t length, size_t offset) override;
+    boost::optional<u8> ReadByte(size_t offset) const override;
+    std::vector<u8> ReadBytes(size_t size, size_t offset) const override;
+    std::vector<u8> ReadAllBytes() const override;
+    bool WriteByte(u8 data, size_t offset) override;
+    size_t WriteBytes(std::vector<u8> data, size_t offset) override;
+
+    bool Rename(const std::string& name) override;
+
+    size_t GetOffset() const;
+
+private:
+    size_t TrimToFit(size_t r_size, size_t r_offset) const;
+
+    std::shared_ptr<VfsFile> file;
+    size_t offset;
+    size_t size;
+    std::string name;
+};
+
+} // namespace FileSys
diff --git a/src/core/file_sys/vfs_real.cpp b/src/core/file_sys/vfs_real.cpp
new file mode 100644
index 000000000..8b95e8c72
--- /dev/null
+++ b/src/core/file_sys/vfs_real.cpp
@@ -0,0 +1,168 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/common_paths.h"
+#include "common/logging/log.h"
+#include "core/file_sys/vfs_real.h"
+
+namespace FileSys {
+
+static std::string PermissionsToCharArray(Mode perms) {
+    std::string out;
+    switch (perms) {
+    case Mode::Read:
+        out += "r";
+        break;
+    case Mode::Write:
+        out += "r+";
+        break;
+    case Mode::Append:
+        out += "a";
+        break;
+    }
+    return out + "b";
+}
+
+RealVfsFile::RealVfsFile(const std::string& path_, Mode perms_)
+    : backing(path_, PermissionsToCharArray(perms_).c_str()), path(path_),
+      parent_path(FileUtil::GetParentPath(path_)),
+      path_components(FileUtil::SplitPathComponents(path_)),
+      parent_components(FileUtil::SliceVector(path_components, 0, path_components.size() - 1)),
+      perms(perms_) {}
+
+std::string RealVfsFile::GetName() const {
+    return path_components.back();
+}
+
+size_t RealVfsFile::GetSize() const {
+    return backing.GetSize();
+}
+
+bool RealVfsFile::Resize(size_t new_size) {
+    return backing.Resize(new_size);
+}
+
+std::shared_ptr<VfsDirectory> RealVfsFile::GetContainingDirectory() const {
+    return std::make_shared<RealVfsDirectory>(parent_path, perms);
+}
+
+bool RealVfsFile::IsWritable() const {
+    return perms == Mode::Append || perms == Mode::Write;
+}
+
+bool RealVfsFile::IsReadable() const {
+    return perms == Mode::Read || perms == Mode::Write;
+}
+
+size_t RealVfsFile::Read(u8* data, size_t length, size_t offset) const {
+    if (!backing.Seek(offset, SEEK_SET))
+        return 0;
+    return backing.ReadBytes(data, length);
+}
+
+size_t RealVfsFile::Write(const u8* data, size_t length, size_t offset) {
+    if (!backing.Seek(offset, SEEK_SET))
+        return 0;
+    return backing.WriteBytes(data, length);
+}
+
+bool RealVfsFile::Rename(const std::string& name) {
+    const auto out = FileUtil::Rename(GetName(), name);
+    path = parent_path + DIR_SEP + name;
+    path_components = parent_components;
+    path_components.push_back(name);
+    backing = FileUtil::IOFile(path, PermissionsToCharArray(perms).c_str());
+    return out;
+}
+
+RealVfsDirectory::RealVfsDirectory(const std::string& path_, Mode perms_)
+    : path(FileUtil::RemoveTrailingSlash(path_)), parent_path(FileUtil::GetParentPath(path)),
+      path_components(FileUtil::SplitPathComponents(path)),
+      parent_components(FileUtil::SliceVector(path_components, 0, path_components.size() - 1)),
+      perms(perms_) {
+    if (!FileUtil::Exists(path) && (perms == Mode::Write || perms == Mode::Append))
+        FileUtil::CreateDir(path);
+    unsigned size;
+    if (perms != Mode::Append) {
+        FileUtil::ForeachDirectoryEntry(
+            &size, path,
+            [this](unsigned* entries_out, const std::string& directory,
+                   const std::string& filename) {
+                std::string full_path = directory + DIR_SEP + filename;
+                if (FileUtil::IsDirectory(full_path))
+                    subdirectories.emplace_back(
+                        std::make_shared<RealVfsDirectory>(full_path, perms));
+                else
+                    files.emplace_back(std::make_shared<RealVfsFile>(full_path, perms));
+                return true;
+            });
+    }
+}
+
+std::vector<std::shared_ptr<VfsFile>> RealVfsDirectory::GetFiles() const {
+    return std::vector<std::shared_ptr<VfsFile>>(files);
+}
+
+std::vector<std::shared_ptr<VfsDirectory>> RealVfsDirectory::GetSubdirectories() const {
+    return std::vector<std::shared_ptr<VfsDirectory>>(subdirectories);
+}
+
+bool RealVfsDirectory::IsWritable() const {
+    return perms == Mode::Write || perms == Mode::Append;
+}
+
+bool RealVfsDirectory::IsReadable() const {
+    return perms == Mode::Read || perms == Mode::Write;
+}
+
+std::string RealVfsDirectory::GetName() const {
+    return path_components.back();
+}
+
+std::shared_ptr<VfsDirectory> RealVfsDirectory::GetParentDirectory() const {
+    if (path_components.size() <= 1)
+        return nullptr;
+
+    return std::make_shared<RealVfsDirectory>(parent_path, perms);
+}
+
+std::shared_ptr<VfsDirectory> RealVfsDirectory::CreateSubdirectory(const std::string& name) {
+    if (!FileUtil::CreateDir(path + DIR_SEP + name))
+        return nullptr;
+    subdirectories.emplace_back(std::make_shared<RealVfsDirectory>(path + DIR_SEP + name, perms));
+    return subdirectories.back();
+}
+
+std::shared_ptr<VfsFile> RealVfsDirectory::CreateFile(const std::string& name) {
+    if (!FileUtil::CreateEmptyFile(path + DIR_SEP + name))
+        return nullptr;
+    files.emplace_back(std::make_shared<RealVfsFile>(path + DIR_SEP + name, perms));
+    return files.back();
+}
+
+bool RealVfsDirectory::DeleteSubdirectory(const std::string& name) {
+    return FileUtil::DeleteDirRecursively(path + DIR_SEP + name);
+}
+
+bool RealVfsDirectory::DeleteFile(const std::string& name) {
+    return FileUtil::Delete(path + DIR_SEP + name);
+}
+
+bool RealVfsDirectory::Rename(const std::string& name) {
+    return FileUtil::Rename(path, parent_path + DIR_SEP + name);
+}
+
+bool RealVfsDirectory::ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) {
+    auto iter = std::find(files.begin(), files.end(), file);
+    if (iter == files.end())
+        return false;
+
+    files[iter - files.begin()] = files.back();
+    files.pop_back();
+
+    subdirectories.emplace_back(dir);
+
+    return true;
+}
+} // namespace FileSys
diff --git a/src/core/file_sys/vfs_real.h b/src/core/file_sys/vfs_real.h
new file mode 100644
index 000000000..01717f485
--- /dev/null
+++ b/src/core/file_sys/vfs_real.h
@@ -0,0 +1,65 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/file_util.h"
+#include "core/file_sys/filesystem.h"
+#include "core/file_sys/vfs.h"
+
+namespace FileSys {
+
+// An implmentation of VfsFile that represents a file on the user's computer.
+struct RealVfsFile : public VfsFile {
+    RealVfsFile(const std::string& name, Mode perms = Mode::Read);
+
+    std::string GetName() const override;
+    size_t GetSize() const override;
+    bool Resize(size_t new_size) override;
+    std::shared_ptr<VfsDirectory> GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    size_t Read(u8* data, size_t length, size_t offset) const override;
+    size_t Write(const u8* data, size_t length, size_t offset) override;
+    bool Rename(const std::string& name) override;
+
+private:
+    FileUtil::IOFile backing;
+    std::string path;
+    std::string parent_path;
+    std::vector<std::string> path_components;
+    std::vector<std::string> parent_components;
+    Mode perms;
+};
+
+// An implementation of VfsDirectory that represents a directory on the user's computer.
+struct RealVfsDirectory : public VfsDirectory {
+    RealVfsDirectory(const std::string& path, Mode perms);
+
+    std::vector<std::shared_ptr<VfsFile>> GetFiles() const override;
+    std::vector<std::shared_ptr<VfsDirectory>> GetSubdirectories() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::string GetName() const override;
+    std::shared_ptr<VfsDirectory> GetParentDirectory() const override;
+    std::shared_ptr<VfsDirectory> CreateSubdirectory(const std::string& name) override;
+    std::shared_ptr<VfsFile> CreateFile(const std::string& name) override;
+    bool DeleteSubdirectory(const std::string& name) override;
+    bool DeleteFile(const std::string& name) override;
+    bool Rename(const std::string& name) override;
+
+protected:
+    bool ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) override;
+
+private:
+    std::string path;
+    std::string parent_path;
+    std::vector<std::string> path_components;
+    std::vector<std::string> parent_components;
+    Mode perms;
+    std::vector<std::shared_ptr<VfsFile>> files;
+    std::vector<std::shared_ptr<VfsDirectory>> subdirectories;
+};
+
+} // namespace FileSys