common: fs: Rework the Common Filesystem interface to make use of std::filesystem (#6270)

* common: fs: fs_types: Create filesystem types

Contains various filesystem types used by the Common::FS library

* common: fs: fs_util: Add std::string to std::u8string conversion utility

* common: fs: path_util: Add utlity functions for paths

Contains various utility functions for getting or manipulating filesystem paths used by the Common::FS library

* common: fs: file: Rewrite the IOFile implementation

* common: fs: Reimplement Common::FS library using std::filesystem

* common: fs: fs_paths: Add fs_paths to replace common_paths

* common: fs: path_util: Add the rest of the path functions

* common: Remove the previous Common::FS implementation

* general: Remove unused fs includes

* string_util: Remove unused function and include

* nvidia_flags: Migrate to the new Common::FS library

* settings: Migrate to the new Common::FS library

* logging: backend: Migrate to the new Common::FS library

* core: Migrate to the new Common::FS library

* perf_stats: Migrate to the new Common::FS library

* reporter: Migrate to the new Common::FS library

* telemetry_session: Migrate to the new Common::FS library

* key_manager: Migrate to the new Common::FS library

* bis_factory: Migrate to the new Common::FS library

* registered_cache: Migrate to the new Common::FS library

* xts_archive: Migrate to the new Common::FS library

* service: acc: Migrate to the new Common::FS library

* applets/profile: Migrate to the new Common::FS library

* applets/web: Migrate to the new Common::FS library

* service: filesystem: Migrate to the new Common::FS library

* loader: Migrate to the new Common::FS library

* gl_shader_disk_cache: Migrate to the new Common::FS library

* nsight_aftermath_tracker: Migrate to the new Common::FS library

* vulkan_library: Migrate to the new Common::FS library

* configure_debug: Migrate to the new Common::FS library

* game_list_worker: Migrate to the new Common::FS library

* config: Migrate to the new Common::FS library

* configure_filesystem: Migrate to the new Common::FS library

* configure_per_game_addons: Migrate to the new Common::FS library

* configure_profile_manager: Migrate to the new Common::FS library

* configure_ui: Migrate to the new Common::FS library

* input_profiles: Migrate to the new Common::FS library

* yuzu_cmd: config: Migrate to the new Common::FS library

* yuzu_cmd: Migrate to the new Common::FS library

* vfs_real: Migrate to the new Common::FS library

* vfs: Migrate to the new Common::FS library

* vfs_libzip: Migrate to the new Common::FS library

* service: bcat: Migrate to the new Common::FS library

* yuzu: main: Migrate to the new Common::FS library

* vfs_real: Delete the contents of an existing file in CreateFile

Current usages of CreateFile expect to delete the contents of an existing file, retain this behavior for now.

* input_profiles: Don't iterate the input profile dir if it does not exist

Silences an error produced in the log if the directory does not exist.

* game_list_worker: Skip parsing file if the returned VfsFile is nullptr

Prevents crashes in GetLoader when the virtual file is nullptr

* common: fs: Validate paths for path length

* service: filesystem: Open the mod load directory as read only

src/common/fs/file.cpp

@@ -0,0 +1,392 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/fs/file.h"
+#include "common/fs/fs.h"
+#include "common/fs/path_util.h"
+#include "common/logging/log.h"
+
+#ifdef _WIN32
+#include <io.h>
+#include <share.h>
+#else
+#include <unistd.h>
+#endif
+
+#ifdef _MSC_VER
+#define fileno _fileno
+#define fseeko _fseeki64
+#define ftello _ftelli64
+#endif
+
+namespace Common::FS {
+
+namespace fs = std::filesystem;
+
+namespace {
+
+#ifdef _WIN32
+
+/**
+ * Converts the file access mode and file type enums to a file access mode wide string.
+ *
+ * @param mode File access mode
+ * @param type File type
+ *
+ * @returns A pointer to a wide string representing the file access mode.
+ */
+[[nodiscard]] constexpr const wchar_t* AccessModeToWStr(FileAccessMode mode, FileType type) {
+    switch (type) {
+    case FileType::BinaryFile:
+        switch (mode) {
+        case FileAccessMode::Read:
+            return L"rb";
+        case FileAccessMode::Write:
+            return L"wb";
+        case FileAccessMode::Append:
+            return L"ab";
+        case FileAccessMode::ReadWrite:
+            return L"r+b";
+        case FileAccessMode::ReadAppend:
+            return L"a+b";
+        }
+        break;
+    case FileType::TextFile:
+        switch (mode) {
+        case FileAccessMode::Read:
+            return L"r";
+        case FileAccessMode::Write:
+            return L"w";
+        case FileAccessMode::Append:
+            return L"a";
+        case FileAccessMode::ReadWrite:
+            return L"r+";
+        case FileAccessMode::ReadAppend:
+            return L"a+";
+        }
+        break;
+    }
+
+    return L"";
+}
+
+/**
+ * Converts the file-share access flag enum to a Windows defined file-share access flag.
+ *
+ * @param flag File-share access flag
+ *
+ * @returns Windows defined file-share access flag.
+ */
+[[nodiscard]] constexpr int ToWindowsFileShareFlag(FileShareFlag flag) {
+    switch (flag) {
+    case FileShareFlag::ShareNone:
+    default:
+        return _SH_DENYRW;
+    case FileShareFlag::ShareReadOnly:
+        return _SH_DENYWR;
+    case FileShareFlag::ShareWriteOnly:
+        return _SH_DENYRD;
+    case FileShareFlag::ShareReadWrite:
+        return _SH_DENYNO;
+    }
+}
+
+#else
+
+/**
+ * Converts the file access mode and file type enums to a file access mode string.
+ *
+ * @param mode File access mode
+ * @param type File type
+ *
+ * @returns A pointer to a string representing the file access mode.
+ */
+[[nodiscard]] constexpr const char* AccessModeToStr(FileAccessMode mode, FileType type) {
+    switch (type) {
+    case FileType::BinaryFile:
+        switch (mode) {
+        case FileAccessMode::Read:
+            return "rb";
+        case FileAccessMode::Write:
+            return "wb";
+        case FileAccessMode::Append:
+            return "ab";
+        case FileAccessMode::ReadWrite:
+            return "r+b";
+        case FileAccessMode::ReadAppend:
+            return "a+b";
+        }
+        break;
+    case FileType::TextFile:
+        switch (mode) {
+        case FileAccessMode::Read:
+            return "r";
+        case FileAccessMode::Write:
+            return "w";
+        case FileAccessMode::Append:
+            return "a";
+        case FileAccessMode::ReadWrite:
+            return "r+";
+        case FileAccessMode::ReadAppend:
+            return "a+";
+        }
+        break;
+    }
+
+    return "";
+}
+
+#endif
+
+/**
+ * Converts the seek origin enum to a seek origin integer.
+ *
+ * @param origin Seek origin
+ *
+ * @returns Seek origin integer.
+ */
+[[nodiscard]] constexpr int ToSeekOrigin(SeekOrigin origin) {
+    switch (origin) {
+    case SeekOrigin::SetOrigin:
+    default:
+        return SEEK_SET;
+    case SeekOrigin::CurrentPosition:
+        return SEEK_CUR;
+    case SeekOrigin::End:
+        return SEEK_END;
+    }
+}
+
+} // Anonymous namespace
+
+std::string ReadStringFromFile(const std::filesystem::path& path, FileType type) {
+    if (!IsFile(path)) {
+        return "";
+    }
+
+    IOFile io_file{path, FileAccessMode::Read, type};
+
+    return io_file.ReadString(io_file.GetSize());
+}
+
+size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
+                         std::string_view string) {
+    if (!IsFile(path)) {
+        return 0;
+    }
+
+    IOFile io_file{path, FileAccessMode::Write, type};
+
+    return io_file.WriteString(string);
+}
+
+size_t AppendStringToFile(const std::filesystem::path& path, FileType type,
+                          std::string_view string) {
+    if (!Exists(path)) {
+        return WriteStringToFile(path, type, string);
+    }
+
+    if (!IsFile(path)) {
+        return 0;
+    }
+
+    IOFile io_file{path, FileAccessMode::Append, type};
+
+    return io_file.WriteString(string);
+}
+
+IOFile::IOFile() = default;
+
+IOFile::IOFile(const std::string& path, FileAccessMode mode, FileType type, FileShareFlag flag) {
+    Open(path, mode, type, flag);
+}
+
+IOFile::IOFile(std::string_view path, FileAccessMode mode, FileType type, FileShareFlag flag) {
+    Open(path, mode, type, flag);
+}
+
+IOFile::IOFile(const fs::path& path, FileAccessMode mode, FileType type, FileShareFlag flag) {
+    Open(path, mode, type, flag);
+}
+
+IOFile::~IOFile() {
+    Close();
+}
+
+IOFile::IOFile(IOFile&& other) noexcept {
+    std::swap(file_path, other.file_path);
+    std::swap(file_access_mode, other.file_access_mode);
+    std::swap(file_type, other.file_type);
+    std::swap(file, other.file);
+}
+
+IOFile& IOFile::operator=(IOFile&& other) noexcept {
+    std::swap(file_path, other.file_path);
+    std::swap(file_access_mode, other.file_access_mode);
+    std::swap(file_type, other.file_type);
+    std::swap(file, other.file);
+    return *this;
+}
+
+fs::path IOFile::GetPath() const {
+    return file_path;
+}
+
+FileAccessMode IOFile::GetAccessMode() const {
+    return file_access_mode;
+}
+
+FileType IOFile::GetType() const {
+    return file_type;
+}
+
+void IOFile::Open(const fs::path& path, FileAccessMode mode, FileType type, FileShareFlag flag) {
+    Close();
+
+    file_path = path;
+    file_access_mode = mode;
+    file_type = type;
+
+    errno = 0;
+
+#ifdef _WIN32
+    if (flag != FileShareFlag::ShareNone) {
+        file = _wfsopen(path.c_str(), AccessModeToWStr(mode, type), ToWindowsFileShareFlag(flag));
+    } else {
+        _wfopen_s(&file, path.c_str(), AccessModeToWStr(mode, type));
+    }
+#else
+    file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
+#endif
+
+    if (!IsOpen()) {
+        const auto ec = std::error_code{errno, std::generic_category()};
+        LOG_ERROR(Common_Filesystem, "Failed to open the file at path={}, ec_message={}",
+                  PathToUTF8String(file_path), ec.message());
+    }
+}
+
+void IOFile::Close() {
+    if (!IsOpen()) {
+        return;
+    }
+
+    errno = 0;
+
+    const auto close_result = std::fclose(file) == 0;
+
+    if (!close_result) {
+        const auto ec = std::error_code{errno, std::generic_category()};
+        LOG_ERROR(Common_Filesystem, "Failed to close the file at path={}, ec_message={}",
+                  PathToUTF8String(file_path), ec.message());
+    }
+
+    file = nullptr;
+}
+
+bool IOFile::IsOpen() const {
+    return file != nullptr;
+}
+
+std::string IOFile::ReadString(size_t length) const {
+    std::vector<char> string_buffer(length);
+
+    const auto chars_read = ReadSpan<char>(string_buffer);
+    const auto string_size = chars_read != length ? chars_read : length;
+
+    return std::string{string_buffer.data(), string_size};
+}
+
+size_t IOFile::WriteString(std::span<const char> string) const {
+    return WriteSpan(string);
+}
+
+bool IOFile::Flush() const {
+    if (!IsOpen()) {
+        return false;
+    }
+
+    errno = 0;
+
+    const auto flush_result = std::fflush(file) == 0;
+
+    if (!flush_result) {
+        const auto ec = std::error_code{errno, std::generic_category()};
+        LOG_ERROR(Common_Filesystem, "Failed to flush the file at path={}, ec_message={}",
+                  PathToUTF8String(file_path), ec.message());
+    }
+
+    return flush_result;
+}
+
+bool IOFile::SetSize(u64 size) const {
+    if (!IsOpen()) {
+        return false;
+    }
+
+    errno = 0;
+
+#ifdef _WIN32
+    const auto set_size_result = _chsize_s(fileno(file), static_cast<s64>(size)) == 0;
+#else
+    const auto set_size_result = ftruncate(fileno(file), static_cast<s64>(size)) == 0;
+#endif
+
+    if (!set_size_result) {
+        const auto ec = std::error_code{errno, std::generic_category()};
+        LOG_ERROR(Common_Filesystem, "Failed to resize the file at path={}, size={}, ec_message={}",
+                  PathToUTF8String(file_path), size, ec.message());
+    }
+
+    return set_size_result;
+}
+
+u64 IOFile::GetSize() const {
+    if (!IsOpen()) {
+        return 0;
+    }
+
+    std::error_code ec;
+
+    const auto file_size = fs::file_size(file_path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to retrieve the file size of path={}, ec_message={}",
+                  PathToUTF8String(file_path), ec.message());
+        return 0;
+    }
+
+    return file_size;
+}
+
+bool IOFile::Seek(s64 offset, SeekOrigin origin) const {
+    if (!IsOpen()) {
+        return false;
+    }
+
+    errno = 0;
+
+    const auto seek_result = fseeko(file, offset, ToSeekOrigin(origin)) == 0;
+
+    if (!seek_result) {
+        const auto ec = std::error_code{errno, std::generic_category()};
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to seek the file at path={}, offset={}, origin={}, ec_message={}",
+                  PathToUTF8String(file_path), offset, origin, ec.message());
+    }
+
+    return seek_result;
+}
+
+s64 IOFile::Tell() const {
+    if (!IsOpen()) {
+        return 0;
+    }
+
+    errno = 0;
+
+    return ftello(file);
+}
+
+} // namespace Common::FS

src/common/fs/file.h

@@ -0,0 +1,450 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <cstdio>
+#include <filesystem>
+#include <fstream>
+#include <span>
+#include <type_traits>
+#include <vector>
+
+#include "common/concepts.h"
+#include "common/fs/fs_types.h"
+#include "common/fs/fs_util.h"
+
+namespace Common::FS {
+
+enum class SeekOrigin {
+    SetOrigin,       // Seeks from the start of the file.
+    CurrentPosition, // Seeks from the current file pointer position.
+    End,             // Seeks from the end of the file.
+};
+
+/**
+ * Opens a file stream at path with the specified open mode.
+ *
+ * @param file_stream Reference to file stream
+ * @param path Filesystem path
+ * @param open_mode File stream open mode
+ */
+template <typename FileStream>
+void OpenFileStream(FileStream& file_stream, const std::filesystem::path& path,
+                    std::ios_base::openmode open_mode) {
+    file_stream.open(path, open_mode);
+}
+
+#ifdef _WIN32
+template <typename FileStream, typename Path>
+void OpenFileStream(FileStream& file_stream, const Path& path, std::ios_base::openmode open_mode) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        file_stream.open(ToU8String(path), open_mode);
+    } else {
+        file_stream.open(std::filesystem::path{path}, open_mode);
+    }
+}
+#endif
+
+/**
+ * Reads an entire file at path and returns a string of the contents read from the file.
+ * If the filesystem object at path is not a file, this function returns an empty string.
+ *
+ * @param path Filesystem path
+ * @param type File type
+ *
+ * @returns A string of the contents read from the file.
+ */
+[[nodiscard]] std::string ReadStringFromFile(const std::filesystem::path& path, FileType type);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] std::string ReadStringFromFile(const Path& path, FileType type) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return ReadStringFromFile(ToU8String(path), type);
+    } else {
+        return ReadStringFromFile(std::filesystem::path{path}, type);
+    }
+}
+#endif
+
+/**
+ * Writes a string to a file at path and returns the number of characters successfully written.
+ * If an file already exists at path, its contents will be erased.
+ * If the filesystem object at path is not a file, this function returns 0.
+ *
+ * @param path Filesystem path
+ * @param type File type
+ *
+ * @returns Number of characters successfully written.
+ */
+[[nodiscard]] size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
+                                       std::string_view string);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] size_t WriteStringToFile(const Path& path, FileType type, std::string_view string) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return WriteStringToFile(ToU8String(path), type, string);
+    } else {
+        return WriteStringToFile(std::filesystem::path{path}, type, string);
+    }
+}
+#endif
+
+/**
+ * Appends a string to a file at path and returns the number of characters successfully written.
+ * If a file does not exist at path, WriteStringToFile is called instead.
+ * If the filesystem object at path is not a file, this function returns 0.
+ *
+ * @param path Filesystem path
+ * @param type File type
+ *
+ * @returns Number of characters successfully written.
+ */
+[[nodiscard]] size_t AppendStringToFile(const std::filesystem::path& path, FileType type,
+                                        std::string_view string);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] size_t AppendStringToFile(const Path& path, FileType type, std::string_view string) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return AppendStringToFile(ToU8String(path), type, string);
+    } else {
+        return AppendStringToFile(std::filesystem::path{path}, type, string);
+    }
+}
+#endif
+
+class IOFile final : NonCopyable {
+public:
+    IOFile();
+
+    explicit IOFile(const std::string& path, FileAccessMode mode,
+                    FileType type = FileType::BinaryFile,
+                    FileShareFlag flag = FileShareFlag::ShareReadOnly);
+
+    explicit IOFile(std::string_view path, FileAccessMode mode,
+                    FileType type = FileType::BinaryFile,
+                    FileShareFlag flag = FileShareFlag::ShareReadOnly);
+
+    /**
+     * An IOFile is a lightweight wrapper on C Library file operations.
+     * Automatically closes an open file on the destruction of an IOFile object.
+     *
+     * @param path Filesystem path
+     * @param mode File access mode
+     * @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
+     * @param flag (Windows only) File-share access flag, default is ShareReadOnly
+     */
+    explicit IOFile(const std::filesystem::path& path, FileAccessMode mode,
+                    FileType type = FileType::BinaryFile,
+                    FileShareFlag flag = FileShareFlag::ShareReadOnly);
+
+    virtual ~IOFile();
+
+    IOFile(IOFile&& other) noexcept;
+    IOFile& operator=(IOFile&& other) noexcept;
+
+    /**
+     * Gets the path of the file.
+     *
+     * @returns The path of the file.
+     */
+    [[nodiscard]] std::filesystem::path GetPath() const;
+
+    /**
+     * Gets the access mode of the file.
+     *
+     * @returns The access mode of the file.
+     */
+    [[nodiscard]] FileAccessMode GetAccessMode() const;
+
+    /**
+     * Gets the type of the file.
+     *
+     * @returns The type of the file.
+     */
+    [[nodiscard]] FileType GetType() const;
+
+    /**
+     * Opens a file at path with the specified file access mode.
+     * This function behaves differently depending on the FileAccessMode.
+     * These behaviors are documented in each enum value of FileAccessMode.
+     *
+     * @param path Filesystem path
+     * @param mode File access mode
+     * @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
+     * @param flag (Windows only) File-share access flag, default is ShareReadOnly
+     */
+    void Open(const std::filesystem::path& path, FileAccessMode mode,
+              FileType type = FileType::BinaryFile,
+              FileShareFlag flag = FileShareFlag::ShareReadOnly);
+
+#ifdef _WIN32
+    template <typename Path>
+    [[nodiscard]] void Open(const Path& path, FileAccessMode mode,
+                            FileType type = FileType::BinaryFile,
+                            FileShareFlag flag = FileShareFlag::ShareReadOnly) {
+        using ValueType = typename Path::value_type;
+        if constexpr (IsChar<ValueType>) {
+            Open(ToU8String(path), mode, type, flag);
+        } else {
+            Open(std::filesystem::path{path}, mode, type, flag);
+        }
+    }
+#endif
+
+    /// Closes the file if it is opened.
+    void Close();
+
+    /**
+     * Checks whether the file is open.
+     * Use this to check whether the calls to Open() or Close() succeeded.
+     *
+     * @returns True if the file is open, false otherwise.
+     */
+    [[nodiscard]] bool IsOpen() const;
+
+    /**
+     * Helper function which deduces the value type of a contiguous STL container used in ReadSpan.
+     * If T is not a contiguous STL container as defined by the concept IsSTLContainer, this calls
+     * ReadObject and T must be a trivially copyable object.
+     *
+     * See ReadSpan for more details if T is a contiguous container.
+     * See ReadObject for more details if T is a trivially copyable object.
+     *
+     * @tparam T Contiguous container or trivially copyable object
+     *
+     * @param data Container of T::value_type data or reference to object
+     *
+     * @returns Count of T::value_type data or objects successfully read.
+     */
+    template <typename T>
+    [[nodiscard]] size_t Read(T& data) const {
+        if constexpr (IsSTLContainer<T>) {
+            using ContiguousType = typename T::value_type;
+            static_assert(std::is_trivially_copyable_v<ContiguousType>,
+                          "Data type must be trivially copyable.");
+            return ReadSpan<ContiguousType>(data);
+        } else {
+            return ReadObject(data) ? 1 : 0;
+        }
+    }
+
+    /**
+     * Helper function which deduces the value type of a contiguous STL container used in WriteSpan.
+     * If T is not a contiguous STL container as defined by the concept IsSTLContainer, this calls
+     * WriteObject and T must be a trivially copyable object.
+     *
+     * See WriteSpan for more details if T is a contiguous container.
+     * See WriteObject for more details if T is a trivially copyable object.
+     *
+     * @tparam T Contiguous container or trivially copyable object
+     *
+     * @param data Container of T::value_type data or const reference to object
+     *
+     * @returns Count of T::value_type data or objects successfully written.
+     */
+    template <typename T>
+    [[nodiscard]] size_t Write(const T& data) const {
+        if constexpr (IsSTLContainer<T>) {
+            using ContiguousType = typename T::value_type;
+            static_assert(std::is_trivially_copyable_v<ContiguousType>,
+                          "Data type must be trivially copyable.");
+            return WriteSpan<ContiguousType>(data);
+        } else {
+            static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+            return WriteObject(data) ? 1 : 0;
+        }
+    }
+
+    /**
+     * Reads a span of T data from a file sequentially.
+     * This function reads from the current position of the file pointer and
+     * advances it by the (count of T * sizeof(T)) bytes successfully read.
+     *
+     * Failures occur when:
+     * - The file is not open
+     * - The opened file lacks read permissions
+     * - Attempting to read beyond the end-of-file
+     *
+     * @tparam T Data type
+     *
+     * @param data Span of T data
+     *
+     * @returns Count of T data successfully read.
+     */
+    template <typename T>
+    [[nodiscard]] size_t ReadSpan(std::span<T> data) const {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+
+        if (!IsOpen()) {
+            return 0;
+        }
+
+        return std::fread(data.data(), sizeof(T), data.size(), file);
+    }
+
+    /**
+     * Writes a span of T data to a file sequentially.
+     * This function writes from the current position of the file pointer and
+     * advances it by the (count of T * sizeof(T)) bytes successfully written.
+     *
+     * Failures occur when:
+     * - The file is not open
+     * - The opened file lacks write permissions
+     *
+     * @tparam T Data type
+     *
+     * @param data Span of T data
+     *
+     * @returns Count of T data successfully written.
+     */
+    template <typename T>
+    [[nodiscard]] size_t WriteSpan(std::span<const T> data) const {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+
+        if (!IsOpen()) {
+            return 0;
+        }
+
+        return std::fwrite(data.data(), sizeof(T), data.size(), file);
+    }
+
+    /**
+     * Reads a T object from a file sequentially.
+     * This function reads from the current position of the file pointer and
+     * advances it by the sizeof(T) bytes successfully read.
+     *
+     * Failures occur when:
+     * - The file is not open
+     * - The opened file lacks read permissions
+     * - Attempting to read beyond the end-of-file
+     *
+     * @tparam T Data type
+     *
+     * @param object Reference to object
+     *
+     * @returns True if the object is successfully read from the file, false otherwise.
+     */
+    template <typename T>
+    [[nodiscard]] bool ReadObject(T& object) const {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+        static_assert(!std::is_pointer_v<T>, "T must not be a pointer to an object.");
+
+        if (!IsOpen()) {
+            return false;
+        }
+
+        return std::fread(&object, sizeof(T), 1, file) == 1;
+    }
+
+    /**
+     * Writes a T object to a file sequentially.
+     * This function writes from the current position of the file pointer and
+     * advances it by the sizeof(T) bytes successfully written.
+     *
+     * Failures occur when:
+     * - The file is not open
+     * - The opened file lacks write permissions
+     *
+     * @tparam T Data type
+     *
+     * @param object Const reference to object
+     *
+     * @returns True if the object is successfully written to the file, false otherwise.
+     */
+    template <typename T>
+    [[nodiscard]] bool WriteObject(const T& object) const {
+        static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
+        static_assert(!std::is_pointer_v<T>, "T must not be a pointer to an object.");
+
+        if (!IsOpen()) {
+            return false;
+        }
+
+        return std::fwrite(&object, sizeof(T), 1, file) == 1;
+    }
+
+    /**
+     * Specialized function to read a string of a given length from a file sequentially.
+     * This function writes from the current position of the file pointer and
+     * advances it by the number of characters successfully read.
+     * The size of the returned string may not match length if not all bytes are successfully read.
+     *
+     * @param length Length of the string
+     *
+     * @returns A string read from the file.
+     */
+    [[nodiscard]] std::string ReadString(size_t length) const;
+
+    /**
+     * Specialized function to write a string to a file sequentially.
+     * This function writes from the current position of the file pointer and
+     * advances it by the number of characters successfully written.
+     *
+     * @param string Span of const char backed std::string or std::string_view
+     *
+     * @returns Number of characters successfully written.
+     */
+    [[nodiscard]] size_t WriteString(std::span<const char> string) const;
+
+    /**
+     * Flushes any unwritten buffered data into the file.
+     *
+     * @returns True if the flush was successful, false otherwise.
+     */
+    [[nodiscard]] bool Flush() const;
+
+    /**
+     * Resizes the file to a given size.
+     * If the file is resized to a smaller size, the remainder of the file is discarded.
+     * If the file is resized to a larger size, the new area appears as if zero-filled.
+     *
+     * Failures occur when:
+     * - The file is not open
+     *
+     * @param size File size in bytes
+     *
+     * @returns True if the file resize succeeded, false otherwise.
+     */
+    [[nodiscard]] bool SetSize(u64 size) const;
+
+    /**
+     * Gets the size of the file.
+     *
+     * Failures occur when:
+     * - The file is not open
+     *
+     * @returns The file size in bytes of the file. Returns 0 on failure.
+     */
+    [[nodiscard]] u64 GetSize() const;
+
+    /**
+     * Moves the current position of the file pointer with the specified offset and seek origin.
+     *
+     * @param offset Offset from seek origin
+     * @param origin Seek origin
+     *
+     * @returns True if the file pointer has moved to the specified offset, false otherwise.
+     */
+    [[nodiscard]] bool Seek(s64 offset, SeekOrigin origin = SeekOrigin::SetOrigin) const;
+
+    /**
+     * Gets the current position of the file pointer.
+     *
+     * @returns The current position of the file pointer.
+     */
+    [[nodiscard]] s64 Tell() const;
+
+private:
+    std::filesystem::path file_path;
+    FileAccessMode file_access_mode;
+    FileType file_type;
+
+    std::FILE* file = nullptr;
+};
+
+} // namespace Common::FS

src/common/fs/fs.cpp

@@ -0,0 +1,610 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/fs/file.h"
+#include "common/fs/fs.h"
+#include "common/fs/path_util.h"
+#include "common/logging/log.h"
+
+namespace Common::FS {
+
+namespace fs = std::filesystem;
+
+// File Operations
+
+bool NewFile(const fs::path& path, u64 size) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (!Exists(path.parent_path())) {
+        LOG_ERROR(Common_Filesystem, "Parent directory of path={} does not exist",
+                  PathToUTF8String(path));
+        return false;
+    }
+
+    if (Exists(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} exists", PathToUTF8String(path));
+        return false;
+    }
+
+    IOFile io_file{path, FileAccessMode::Write};
+
+    if (!io_file.IsOpen()) {
+        LOG_ERROR(Common_Filesystem, "Failed to create a file at path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (!io_file.SetSize(size)) {
+        LOG_ERROR(Common_Filesystem, "Failed to resize the file at path={} to size={}",
+                  PathToUTF8String(path), size);
+        return false;
+    }
+
+    io_file.Close();
+
+    LOG_DEBUG(Common_Filesystem, "Successfully created a file at path={} with size={}",
+              PathToUTF8String(path), size);
+
+    return true;
+}
+
+bool RemoveFile(const fs::path& path) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (!Exists(path)) {
+        LOG_DEBUG(Common_Filesystem, "Filesystem object at path={} does not exist",
+                  PathToUTF8String(path));
+        return true;
+    }
+
+    if (!IsFile(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a file",
+                  PathToUTF8String(path));
+        return false;
+    }
+
+    std::error_code ec;
+
+    fs::remove(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to remove the file at path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully removed the file at path={}",
+              PathToUTF8String(path));
+
+    return true;
+}
+
+bool RenameFile(const fs::path& old_path, const fs::path& new_path) {
+    if (!ValidatePath(old_path) || !ValidatePath(new_path)) {
+        LOG_ERROR(Common_Filesystem,
+                  "One or both input path(s) is not valid, old_path={}, new_path={}",
+                  PathToUTF8String(old_path), PathToUTF8String(new_path));
+        return false;
+    }
+
+    if (!Exists(old_path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at old_path={} does not exist",
+                  PathToUTF8String(old_path));
+        return false;
+    }
+
+    if (!IsFile(old_path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at old_path={} is not a file",
+                  PathToUTF8String(old_path));
+        return false;
+    }
+
+    if (Exists(new_path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at new_path={} exists",
+                  PathToUTF8String(new_path));
+        return false;
+    }
+
+    std::error_code ec;
+
+    fs::rename(old_path, new_path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to rename the file from old_path={} to new_path={}, ec_message={}",
+                  PathToUTF8String(old_path), PathToUTF8String(new_path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully renamed the file from old_path={} to new_path={}",
+              PathToUTF8String(old_path), PathToUTF8String(new_path));
+
+    return true;
+}
+
+std::shared_ptr<IOFile> FileOpen(const fs::path& path, FileAccessMode mode, FileType type,
+                                 FileShareFlag flag) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return nullptr;
+    }
+
+    if (!IsFile(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a file",
+                  PathToUTF8String(path));
+        return nullptr;
+    }
+
+    auto io_file = std::make_shared<IOFile>(path, mode, type, flag);
+
+    if (!io_file->IsOpen()) {
+        io_file.reset();
+
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to open the file at path={} with mode={}, type={}, flag={}",
+                  PathToUTF8String(path), mode, type, flag);
+
+        return nullptr;
+    }
+
+    LOG_DEBUG(Common_Filesystem,
+              "Successfully opened the file at path={} with mode={}, type={}, flag={}",
+              PathToUTF8String(path), mode, type, flag);
+
+    return io_file;
+}
+
+// Directory Operations
+
+bool CreateDir(const fs::path& path) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (!Exists(path.parent_path())) {
+        LOG_ERROR(Common_Filesystem, "Parent directory of path={} does not exist",
+                  PathToUTF8String(path));
+        return false;
+    }
+
+    if (IsDir(path)) {
+        LOG_DEBUG(Common_Filesystem, "Filesystem object at path={} exists and is a directory",
+                  PathToUTF8String(path));
+        return true;
+    }
+
+    std::error_code ec;
+
+    fs::create_directory(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to create the directory at path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully created the directory at path={}",
+              PathToUTF8String(path));
+
+    return true;
+}
+
+bool CreateDirs(const fs::path& path) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (IsDir(path)) {
+        LOG_DEBUG(Common_Filesystem, "Filesystem object at path={} exists and is a directory",
+                  PathToUTF8String(path));
+        return true;
+    }
+
+    std::error_code ec;
+
+    fs::create_directories(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to create the directories at path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully created the directories at path={}",
+              PathToUTF8String(path));
+
+    return true;
+}
+
+bool CreateParentDir(const fs::path& path) {
+    return CreateDir(path.parent_path());
+}
+
+bool CreateParentDirs(const fs::path& path) {
+    return CreateDirs(path.parent_path());
+}
+
+bool RemoveDir(const fs::path& path) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (!Exists(path)) {
+        LOG_DEBUG(Common_Filesystem, "Filesystem object at path={} does not exist",
+                  PathToUTF8String(path));
+        return true;
+    }
+
+    if (!IsDir(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a directory",
+                  PathToUTF8String(path));
+        return false;
+    }
+
+    std::error_code ec;
+
+    fs::remove(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to remove the directory at path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully removed the directory at path={}",
+              PathToUTF8String(path));
+
+    return true;
+}
+
+bool RemoveDirRecursively(const fs::path& path) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (!Exists(path)) {
+        LOG_DEBUG(Common_Filesystem, "Filesystem object at path={} does not exist",
+                  PathToUTF8String(path));
+        return true;
+    }
+
+    if (!IsDir(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a directory",
+                  PathToUTF8String(path));
+        return false;
+    }
+
+    std::error_code ec;
+
+    fs::remove_all(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to remove the directory and its contents at path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully removed the directory and its contents at path={}",
+              PathToUTF8String(path));
+
+    return true;
+}
+
+bool RemoveDirContentsRecursively(const fs::path& path) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+    if (!Exists(path)) {
+        LOG_DEBUG(Common_Filesystem, "Filesystem object at path={} does not exist",
+                  PathToUTF8String(path));
+        return true;
+    }
+
+    if (!IsDir(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a directory",
+                  PathToUTF8String(path));
+        return false;
+    }
+
+    std::error_code ec;
+
+    for (const auto& entry : fs::recursive_directory_iterator(path, ec)) {
+        if (ec) {
+            LOG_ERROR(Common_Filesystem,
+                      "Failed to completely enumerate the directory at path={}, ec_message={}",
+                      PathToUTF8String(path), ec.message());
+            break;
+        }
+
+        fs::remove(entry.path(), ec);
+
+        if (ec) {
+            LOG_ERROR(Common_Filesystem,
+                      "Failed to remove the filesystem object at path={}, ec_message={}",
+                      PathToUTF8String(entry.path()), ec.message());
+            break;
+        }
+    }
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to remove all the contents of the directory at path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem,
+              "Successfully removed all the contents of the directory at path={}",
+              PathToUTF8String(path));
+
+    return true;
+}
+
+bool RenameDir(const fs::path& old_path, const fs::path& new_path) {
+    if (!ValidatePath(old_path) || !ValidatePath(new_path)) {
+        LOG_ERROR(Common_Filesystem,
+                  "One or both input path(s) is not valid, old_path={}, new_path={}",
+                  PathToUTF8String(old_path), PathToUTF8String(new_path));
+        return false;
+    }
+
+    if (!Exists(old_path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at old_path={} does not exist",
+                  PathToUTF8String(old_path));
+        return false;
+    }
+
+    if (!IsDir(old_path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at old_path={} is not a directory",
+                  PathToUTF8String(old_path));
+        return false;
+    }
+
+    if (Exists(new_path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at new_path={} exists",
+                  PathToUTF8String(new_path));
+        return false;
+    }
+
+    std::error_code ec;
+
+    fs::rename(old_path, new_path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to rename the file from old_path={} to new_path={}, ec_message={}",
+                  PathToUTF8String(old_path), PathToUTF8String(new_path), ec.message());
+        return false;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully renamed the file from old_path={} to new_path={}",
+              PathToUTF8String(old_path), PathToUTF8String(new_path));
+
+    return true;
+}
+
+void IterateDirEntries(const std::filesystem::path& path, const DirEntryCallable& callback,
+                       DirEntryFilter filter) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return;
+    }
+
+    if (!Exists(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} does not exist",
+                  PathToUTF8String(path));
+        return;
+    }
+
+    if (!IsDir(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a directory",
+                  PathToUTF8String(path));
+        return;
+    }
+
+    bool callback_error = false;
+
+    std::error_code ec;
+
+    for (const auto& entry : fs::directory_iterator(path, ec)) {
+        if (ec) {
+            break;
+        }
+
+        if (True(filter & DirEntryFilter::File) &&
+            entry.status().type() == fs::file_type::regular) {
+            if (!callback(entry.path())) {
+                callback_error = true;
+                break;
+            }
+        }
+
+        if (True(filter & DirEntryFilter::Directory) &&
+            entry.status().type() == fs::file_type::directory) {
+            if (!callback(entry.path())) {
+                callback_error = true;
+                break;
+            }
+        }
+    }
+
+    if (callback_error || ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to visit all the directory entries of path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully visited all the directory entries of path={}",
+              PathToUTF8String(path));
+}
+
+void IterateDirEntriesRecursively(const std::filesystem::path& path,
+                                  const DirEntryCallable& callback, DirEntryFilter filter) {
+    if (!ValidatePath(path)) {
+        LOG_ERROR(Common_Filesystem, "Input path is not valid, path={}", PathToUTF8String(path));
+        return;
+    }
+
+    if (!Exists(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} does not exist",
+                  PathToUTF8String(path));
+        return;
+    }
+
+    if (!IsDir(path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at path={} is not a directory",
+                  PathToUTF8String(path));
+        return;
+    }
+
+    bool callback_error = false;
+
+    std::error_code ec;
+
+    for (const auto& entry : fs::recursive_directory_iterator(path, ec)) {
+        if (ec) {
+            break;
+        }
+
+        if (True(filter & DirEntryFilter::File) &&
+            entry.status().type() == fs::file_type::regular) {
+            if (!callback(entry.path())) {
+                callback_error = true;
+                break;
+            }
+        }
+
+        if (True(filter & DirEntryFilter::Directory) &&
+            entry.status().type() == fs::file_type::directory) {
+            if (!callback(entry.path())) {
+                callback_error = true;
+                break;
+            }
+        }
+    }
+
+    if (callback_error || ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to visit all the directory entries of path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return;
+    }
+
+    LOG_DEBUG(Common_Filesystem, "Successfully visited all the directory entries of path={}",
+              PathToUTF8String(path));
+}
+
+// Generic Filesystem Operations
+
+bool Exists(const fs::path& path) {
+    return fs::exists(path);
+}
+
+bool IsFile(const fs::path& path) {
+    return fs::is_regular_file(path);
+}
+
+bool IsDir(const fs::path& path) {
+    return fs::is_directory(path);
+}
+
+fs::path GetCurrentDir() {
+    std::error_code ec;
+
+    const auto current_path = fs::current_path(ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to get the current path, ec_message={}", ec.message());
+        return {};
+    }
+
+    return current_path;
+}
+
+bool SetCurrentDir(const fs::path& path) {
+    std::error_code ec;
+
+    fs::current_path(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to set the current path to path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return false;
+    }
+
+    return true;
+}
+
+fs::file_type GetEntryType(const fs::path& path) {
+    std::error_code ec;
+
+    const auto file_status = fs::status(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to retrieve the entry type of path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return fs::file_type::not_found;
+    }
+
+    return file_status.type();
+}
+
+u64 GetSize(const fs::path& path) {
+    std::error_code ec;
+
+    const auto file_size = fs::file_size(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem, "Failed to retrieve the file size of path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return 0;
+    }
+
+    return file_size;
+}
+
+u64 GetFreeSpaceSize(const fs::path& path) {
+    std::error_code ec;
+
+    const auto space_info = fs::space(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to retrieve the available free space of path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return 0;
+    }
+
+    return space_info.free;
+}
+
+u64 GetTotalSpaceSize(const fs::path& path) {
+    std::error_code ec;
+
+    const auto space_info = fs::space(path, ec);
+
+    if (ec) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to retrieve the total capacity of path={}, ec_message={}",
+                  PathToUTF8String(path), ec.message());
+        return 0;
+    }
+
+    return space_info.capacity;
+}
+
+} // namespace Common::FS

src/common/fs/fs.h

@@ -0,0 +1,582 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <filesystem>
+#include <memory>
+
+#include "common/fs/fs_types.h"
+#include "common/fs/fs_util.h"
+
+namespace Common::FS {
+
+class IOFile;
+
+// File Operations
+
+/**
+ * Creates a new file at path with the specified size.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - The input path's parent directory does not exist
+ * - Filesystem object at path exists
+ * - Filesystem at path is read only
+ *
+ * @param path Filesystem path
+ * @param size File size
+ *
+ * @returns True if the file creation succeeds, false otherwise.
+ */
+[[nodiscard]] bool NewFile(const std::filesystem::path& path, u64 size = 0);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool NewFile(const Path& path, u64 size = 0) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return NewFile(ToU8String(path), size);
+    } else {
+        return NewFile(std::filesystem::path{path}, size);
+    }
+}
+#endif
+
+/**
+ * Removes a file at path.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem object at path is not a file
+ * - Filesystem at path is read only
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if file removal succeeds or file does not exist, false otherwise.
+ */
+[[nodiscard]] bool RemoveFile(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool RemoveFile(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return RemoveFile(ToU8String(path));
+    } else {
+        return RemoveFile(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Renames a file from old_path to new_path.
+ *
+ * Failures occur when:
+ * - One or both input path(s) is not valid
+ * - Filesystem object at old_path does not exist
+ * - Filesystem object at old_path is not a file
+ * - Filesystem object at new_path exists
+ * - Filesystem at either path is read only
+ *
+ * @param old_path Old filesystem path
+ * @param new_path New filesystem path
+ *
+ * @returns True if file rename succeeds, false otherwise.
+ */
+[[nodiscard]] bool RenameFile(const std::filesystem::path& old_path,
+                              const std::filesystem::path& new_path);
+
+#ifdef _WIN32
+template <typename Path1, typename Path2>
+[[nodiscard]] bool RenameFile(const Path1& old_path, const Path2& new_path) {
+    using ValueType1 = typename Path1::value_type;
+    using ValueType2 = typename Path2::value_type;
+    if constexpr (IsChar<ValueType1> && IsChar<ValueType2>) {
+        return RenameFile(ToU8String(old_path), ToU8String(new_path));
+    } else if constexpr (IsChar<ValueType1> && !IsChar<ValueType2>) {
+        return RenameFile(ToU8String(old_path), new_path);
+    } else if constexpr (!IsChar<ValueType1> && IsChar<ValueType2>) {
+        return RenameFile(old_path, ToU8String(new_path));
+    } else {
+        return RenameFile(std::filesystem::path{old_path}, std::filesystem::path{new_path});
+    }
+}
+#endif
+
+/**
+ * Opens a file at path with the specified file access mode.
+ * This function behaves differently depending on the FileAccessMode.
+ * These behaviors are documented in each enum value of FileAccessMode.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem object at path is not a file
+ * - The file is not opened
+ *
+ * @param path Filesystem path
+ * @param mode File access mode
+ * @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
+ * @param flag (Windows only) File-share access flag, default is ShareReadOnly
+ *
+ * @returns A shared pointer to the opened file. Returns nullptr on failure.
+ */
+[[nodiscard]] std::shared_ptr<IOFile> FileOpen(const std::filesystem::path& path,
+                                               FileAccessMode mode,
+                                               FileType type = FileType::BinaryFile,
+                                               FileShareFlag flag = FileShareFlag::ShareReadOnly);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] std::shared_ptr<IOFile> FileOpen(const Path& path, FileAccessMode mode,
+                                               FileType type = FileType::BinaryFile,
+                                               FileShareFlag flag = FileShareFlag::ShareReadOnly) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return FileOpen(ToU8String(path), mode, type, flag);
+    } else {
+        return FileOpen(std::filesystem::path{path}, mode, type, flag);
+    }
+}
+#endif
+
+// Directory Operations
+
+/**
+ * Creates a directory at path.
+ * Note that this function will *always* assume that the input path is a directory. For example,
+ * if the input path is /path/to/directory/file.txt, it will create a directory called "file.txt".
+ * If you intend to create the parent directory of a file, use CreateParentDir instead.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - The input path's parent directory does not exist
+ * - Filesystem at path is read only
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if directory creation succeeds or directory already exists, false otherwise.
+ */
+[[nodiscard]] bool CreateDir(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool CreateDir(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return CreateDir(ToU8String(path));
+    } else {
+        return CreateDir(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Recursively creates a directory at path.
+ * Note that this function will *always* assume that the input path is a directory. For example,
+ * if the input path is /path/to/directory/file.txt, it will create a directory called "file.txt".
+ * If you intend to create the parent directory of a file, use CreateParentDirs instead.
+ * Unlike CreateDir, this creates all of input path's parent directories if they do not exist.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem at path is read only
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if directory creation succeeds or directory already exists, false otherwise.
+ */
+[[nodiscard]] bool CreateDirs(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool CreateDirs(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return CreateDirs(ToU8String(path));
+    } else {
+        return CreateDirs(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Creates the parent directory of a given path.
+ * This function calls CreateDir(path.parent_path()), see CreateDir for more details.
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if directory creation succeeds or directory already exists, false otherwise.
+ */
+[[nodiscard]] bool CreateParentDir(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool CreateParentDir(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return CreateParentDir(ToU8String(path));
+    } else {
+        return CreateParentDir(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Recursively creates the parent directory of a given path.
+ * This function calls CreateDirs(path.parent_path()), see CreateDirs for more details.
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if directory creation succeeds or directory already exists, false otherwise.
+ */
+[[nodiscard]] bool CreateParentDirs(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool CreateParentDirs(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return CreateParentDirs(ToU8String(path));
+    } else {
+        return CreateParentDirs(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Removes a directory at path.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem object at path is not a directory
+ * - The given directory is not empty
+ * - Filesystem at path is read only
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if directory removal succeeds or directory does not exist, false otherwise.
+ */
+[[nodiscard]] bool RemoveDir(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool RemoveDir(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return RemoveDir(ToU8String(path));
+    } else {
+        return RemoveDir(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Removes all the contents within the given directory and removes the directory itself.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem object at path is not a directory
+ * - Filesystem at path is read only
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if the directory and all of its contents are removed successfully, false otherwise.
+ */
+[[nodiscard]] bool RemoveDirRecursively(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool RemoveDirRecursively(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return RemoveDirRecursively(ToU8String(path));
+    } else {
+        return RemoveDirRecursively(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Removes all the contents within the given directory without removing the directory itself.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem object at path is not a directory
+ * - Filesystem at path is read only
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if all of the directory's contents are removed successfully, false otherwise.
+ */
+[[nodiscard]] bool RemoveDirContentsRecursively(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool RemoveDirContentsRecursively(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return RemoveDirContentsRecursively(ToU8String(path));
+    } else {
+        return RemoveDirContentsRecursively(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Renames a directory from old_path to new_path.
+ *
+ * Failures occur when:
+ * - One or both input path(s) is not valid
+ * - Filesystem object at old_path does not exist
+ * - Filesystem object at old_path is not a directory
+ * - Filesystem object at new_path exists
+ * - Filesystem at either path is read only
+ *
+ * @param old_path Old filesystem path
+ * @param new_path New filesystem path
+ *
+ * @returns True if directory rename succeeds, false otherwise.
+ */
+[[nodiscard]] bool RenameDir(const std::filesystem::path& old_path,
+                             const std::filesystem::path& new_path);
+
+#ifdef _WIN32
+template <typename Path1, typename Path2>
+[[nodiscard]] bool RenameDir(const Path1& old_path, const Path2& new_path) {
+    using ValueType1 = typename Path1::value_type;
+    using ValueType2 = typename Path2::value_type;
+    if constexpr (IsChar<ValueType1> && IsChar<ValueType2>) {
+        return RenameDir(ToU8String(old_path), ToU8String(new_path));
+    } else if constexpr (IsChar<ValueType1> && !IsChar<ValueType2>) {
+        return RenameDir(ToU8String(old_path), new_path);
+    } else if constexpr (!IsChar<ValueType1> && IsChar<ValueType2>) {
+        return RenameDir(old_path, ToU8String(new_path));
+    } else {
+        return RenameDir(std::filesystem::path{old_path}, std::filesystem::path{new_path});
+    }
+}
+#endif
+
+/**
+ * Iterates over the directory entries of a given directory.
+ * This does not iterate over the sub-directories of the given directory.
+ * The DirEntryCallable callback is called for each visited directory entry.
+ * A filter can be set to control which directory entries are visited based on their type.
+ * By default, both files and directories are visited.
+ * If the callback returns false or there is an error, the iteration is immediately halted.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem object at path is not a directory
+ *
+ * @param path Filesystem path
+ * @param callback Callback to be called for each visited directory entry
+ * @param filter Directory entry type filter
+ */
+void IterateDirEntries(const std::filesystem::path& path, const DirEntryCallable& callback,
+                       DirEntryFilter filter = DirEntryFilter::All);
+
+#ifdef _WIN32
+template <typename Path>
+void IterateDirEntries(const Path& path, const DirEntryCallable& callback,
+                       DirEntryFilter filter = DirEntryFilter::All) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        IterateDirEntries(ToU8String(path), callback, filter);
+    } else {
+        IterateDirEntries(std::filesystem::path{path}, callback, filter);
+    }
+}
+#endif
+
+/**
+ * Iterates over the directory entries of a given directory and its sub-directories.
+ * The DirEntryCallable callback is called for each visited directory entry.
+ * A filter can be set to control which directory entries are visited based on their type.
+ * By default, both files and directories are visited.
+ * If the callback returns false or there is an error, the iteration is immediately halted.
+ *
+ * Failures occur when:
+ * - Input path is not valid
+ * - Filesystem object at path does not exist
+ * - Filesystem object at path is not a directory
+ *
+ * @param path Filesystem path
+ * @param callback Callback to be called for each visited directory entry
+ * @param filter Directory entry type filter
+ */
+void IterateDirEntriesRecursively(const std::filesystem::path& path,
+                                  const DirEntryCallable& callback,
+                                  DirEntryFilter filter = DirEntryFilter::All);
+
+#ifdef _WIN32
+template <typename Path>
+void IterateDirEntriesRecursively(const Path& path, const DirEntryCallable& callback,
+                                  DirEntryFilter filter = DirEntryFilter::All) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        IterateDirEntriesRecursively(ToU8String(path), callback, filter);
+    } else {
+        IterateDirEntriesRecursively(std::filesystem::path{path}, callback, filter);
+    }
+}
+#endif
+
+// Generic Filesystem Operations
+
+/**
+ * Returns whether a filesystem object at path exists.
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if a filesystem object at path exists, false otherwise.
+ */
+[[nodiscard]] bool Exists(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool Exists(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return Exists(ToU8String(path));
+    } else {
+        return Exists(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Returns whether a filesystem object at path is a file.
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if a filesystem object at path is a file, false otherwise.
+ */
+[[nodiscard]] bool IsFile(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool IsFile(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return IsFile(ToU8String(path));
+    } else {
+        return IsFile(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Returns whether a filesystem object at path is a directory.
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if a filesystem object at path is a directory, false otherwise.
+ */
+[[nodiscard]] bool IsDir(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool IsDir(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return IsDir(ToU8String(path));
+    } else {
+        return IsDir(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Gets the current working directory.
+ *
+ * @returns The current working directory. Returns an empty path on failure.
+ */
+[[nodiscard]] std::filesystem::path GetCurrentDir();
+
+/**
+ * Sets the current working directory to path.
+ *
+ * @returns True if the current working directory is successfully set, false otherwise.
+ */
+[[nodiscard]] bool SetCurrentDir(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool SetCurrentDir(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return SetCurrentDir(ToU8String(path));
+    } else {
+        return SetCurrentDir(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Gets the entry type of the filesystem object at path.
+ *
+ * @param path Filesystem path
+ *
+ * @returns The entry type of the filesystem object. Returns file_type::not_found on failure.
+ */
+[[nodiscard]] std::filesystem::file_type GetEntryType(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] std::filesystem::file_type GetEntryType(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return GetEntryType(ToU8String(path));
+    } else {
+        return GetEntryType(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Gets the size of the filesystem object at path.
+ *
+ * @param path Filesystem path
+ *
+ * @returns The size in bytes of the filesystem object. Returns 0 on failure.
+ */
+[[nodiscard]] u64 GetSize(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] u64 GetSize(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return GetSize(ToU8String(path));
+    } else {
+        return GetSize(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Gets the free space size of the filesystem at path.
+ *
+ * @param path Filesystem path
+ *
+ * @returns The free space size in bytes of the filesystem at path. Returns 0 on failure.
+ */
+[[nodiscard]] u64 GetFreeSpaceSize(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] u64 GetFreeSpaceSize(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return GetFreeSpaceSize(ToU8String(path));
+    } else {
+        return GetFreeSpaceSize(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Gets the total capacity of the filesystem at path.
+ *
+ * @param path Filesystem path
+ *
+ * @returns The total capacity in bytes of the filesystem at path. Returns 0 on failure.
+ */
+[[nodiscard]] u64 GetTotalSpaceSize(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] u64 GetTotalSpaceSize(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return GetTotalSpaceSize(ToU8String(path));
+    } else {
+        return GetTotalSpaceSize(std::filesystem::path{path});
+    }
+}
+#endif
+
+} // namespace Common::FS

src/common/fs/fs_paths.h

@@ -0,0 +1,27 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+// yuzu data directories
+
+#define YUZU_DIR "yuzu"
+#define PORTABLE_DIR "user"
+
+// Sub-directories contained within a yuzu data directory
+
+#define CACHE_DIR "cache"
+#define CONFIG_DIR "config"
+#define DUMP_DIR "dump"
+#define KEYS_DIR "keys"
+#define LOAD_DIR "load"
+#define LOG_DIR "log"
+#define NAND_DIR "nand"
+#define SCREENSHOTS_DIR "screenshots"
+#define SDMC_DIR "sdmc"
+#define SHADER_DIR "shader"
+
+// yuzu-specific files
+
+#define LOG_FILE "yuzu_log.txt"

src/common/fs/fs_types.h

@@ -0,0 +1,73 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <functional>
+
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+
+namespace Common::FS {
+
+enum class FileAccessMode {
+    /**
+     * If the file at path exists, it opens the file for reading.
+     * If the file at path does not exist, it fails to open the file.
+     */
+    Read = 1 << 0,
+    /**
+     * If the file at path exists, the existing contents of the file are erased.
+     * The empty file is then opened for writing.
+     * If the file at path does not exist, it creates and opens a new empty file for writing.
+     */
+    Write = 1 << 1,
+    /**
+     * If the file at path exists, it opens the file for reading and writing.
+     * If the file at path does not exist, it fails to open the file.
+     */
+    ReadWrite = Read | Write,
+    /**
+     * If the file at path exists, it opens the file for appending.
+     * If the file at path does not exist, it creates and opens a new empty file for appending.
+     */
+    Append = 1 << 2,
+    /**
+     * If the file at path exists, it opens the file for both reading and appending.
+     * If the file at path does not exist, it creates and opens a new empty file for both
+     * reading and appending.
+     */
+    ReadAppend = Read | Append,
+};
+
+enum class FileType {
+    BinaryFile,
+    TextFile,
+};
+
+enum class FileShareFlag {
+    ShareNone,      // Provides exclusive access to the file.
+    ShareReadOnly,  // Provides read only shared access to the file.
+    ShareWriteOnly, // Provides write only shared access to the file.
+    ShareReadWrite, // Provides read and write shared access to the file.
+};
+
+enum class DirEntryFilter {
+    File = 1 << 0,
+    Directory = 1 << 1,
+    All = File | Directory,
+};
+DECLARE_ENUM_FLAG_OPERATORS(DirEntryFilter);
+
+/**
+ * A callback function which takes in the path of a directory entry.
+ *
+ * @param path The path of a directory entry
+ *
+ * @returns A boolean value.
+ *          Return true to indicate whether the callback is successful, false otherwise.
+ */
+using DirEntryCallable = std::function<bool(const std::filesystem::path& path)>;
+
+} // namespace Common::FS

src/common/fs/fs_util.cpp

@@ -0,0 +1,13 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/fs/fs_util.h"
+
+namespace Common::FS {
+
+std::u8string ToU8String(std::string_view utf8_string) {
+    return std::u8string{utf8_string.begin(), utf8_string.end()};
+}
+
+} // namespace Common::FS

src/common/fs/fs_util.h

@@ -0,0 +1,25 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <concepts>
+#include <string>
+#include <string_view>
+
+namespace Common::FS {
+
+template <typename T>
+concept IsChar = std::same_as<T, char>;
+
+/**
+ * Converts a UTF-8 encoded std::string or std::string_view to a std::u8string.
+ *
+ * @param utf8_string UTF-8 encoded string
+ *
+ * @returns UTF-8 encoded std::u8string.
+ */
+[[nodiscard]] std::u8string ToU8String(std::string_view utf8_string);
+
+} // namespace Common::FS

src/common/fs/path_util.cpp

@@ -0,0 +1,432 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <unordered_map>
+
+#include "common/fs/fs.h"
+#include "common/fs/fs_paths.h"
+#include "common/fs/path_util.h"
+#include "common/logging/log.h"
+
+#ifdef _WIN32
+#include <shlobj.h> // Used in GetExeDirectory()
+#else
+#include <cstdlib>     // Used in Get(Home/Data)Directory()
+#include <pwd.h>       // Used in GetHomeDirectory()
+#include <sys/types.h> // Used in GetHomeDirectory()
+#include <unistd.h>    // Used in GetDataDirectory()
+#endif
+
+#ifdef __APPLE__
+#include <sys/param.h> // Used in GetBundleDirectory()
+
+// CFURL contains __attribute__ directives that gcc does not know how to parse, so we need to just
+// ignore them if we're not using clang. The macro is only used to prevent linking against
+// functions that don't exist on older versions of macOS, and the worst case scenario is a linker
+// error, so this is perfectly safe, just inconvenient.
+#ifndef __clang__
+#define availability(...)
+#endif
+#include <CoreFoundation/CFBundle.h> // Used in GetBundleDirectory()
+#include <CoreFoundation/CFString.h> // Used in GetBundleDirectory()
+#include <CoreFoundation/CFURL.h>    // Used in GetBundleDirectory()
+#ifdef availability
+#undef availability
+#endif
+#endif
+
+#ifndef MAX_PATH
+#ifdef _WIN32
+// This is the maximum number of UTF-16 code units permissible in Windows file paths
+#define MAX_PATH 260
+#else
+// This is the maximum number of UTF-8 code units permissible in all other OSes' file paths
+#define MAX_PATH 1024
+#endif
+#endif
+
+namespace Common::FS {
+
+namespace fs = std::filesystem;
+
+/**
+ * The PathManagerImpl is a singleton allowing to manage the mapping of
+ * YuzuPath enums to real filesystem paths.
+ * This class provides 2 functions: GetYuzuPathImpl and SetYuzuPathImpl.
+ * These are used by GetYuzuPath and SetYuzuPath respectively to get or modify
+ * the path mapped by the YuzuPath enum.
+ */
+class PathManagerImpl {
+public:
+    static PathManagerImpl& GetInstance() {
+        static PathManagerImpl path_manager_impl;
+
+        return path_manager_impl;
+    }
+
+    PathManagerImpl(const PathManagerImpl&) = delete;
+    PathManagerImpl& operator=(const PathManagerImpl&) = delete;
+
+    PathManagerImpl(PathManagerImpl&&) = delete;
+    PathManagerImpl& operator=(PathManagerImpl&&) = delete;
+
+    [[nodiscard]] const fs::path& GetYuzuPathImpl(YuzuPath yuzu_path) {
+        return yuzu_paths.at(yuzu_path);
+    }
+
+    void SetYuzuPathImpl(YuzuPath yuzu_path, const fs::path& new_path) {
+        yuzu_paths.insert_or_assign(yuzu_path, new_path);
+    }
+
+private:
+    PathManagerImpl() {
+#ifdef _WIN32
+        auto yuzu_path = GetExeDirectory() / PORTABLE_DIR;
+
+        if (!IsDir(yuzu_path)) {
+            yuzu_path = GetAppDataRoamingDirectory() / YUZU_DIR;
+        }
+
+        GenerateYuzuPath(YuzuPath::YuzuDir, yuzu_path);
+        GenerateYuzuPath(YuzuPath::CacheDir, yuzu_path / CACHE_DIR);
+        GenerateYuzuPath(YuzuPath::ConfigDir, yuzu_path / CONFIG_DIR);
+#else
+        auto yuzu_path = GetCurrentDir() / PORTABLE_DIR;
+
+        if (Exists(yuzu_path) && IsDir(yuzu_path)) {
+            GenerateYuzuPath(YuzuPath::YuzuDir, yuzu_path);
+            GenerateYuzuPath(YuzuPath::CacheDir, yuzu_path / CACHE_DIR);
+            GenerateYuzuPath(YuzuPath::ConfigDir, yuzu_path / CONFIG_DIR);
+        } else {
+            yuzu_path = GetDataDirectory("XDG_DATA_HOME") / YUZU_DIR;
+
+            GenerateYuzuPath(YuzuPath::YuzuDir, yuzu_path);
+            GenerateYuzuPath(YuzuPath::CacheDir, GetDataDirectory("XDG_CACHE_HOME") / YUZU_DIR);
+            GenerateYuzuPath(YuzuPath::ConfigDir, GetDataDirectory("XDG_CONFIG_HOME") / YUZU_DIR);
+        }
+#endif
+
+        GenerateYuzuPath(YuzuPath::DumpDir, yuzu_path / DUMP_DIR);
+        GenerateYuzuPath(YuzuPath::KeysDir, yuzu_path / KEYS_DIR);
+        GenerateYuzuPath(YuzuPath::LoadDir, yuzu_path / LOAD_DIR);
+        GenerateYuzuPath(YuzuPath::LogDir, yuzu_path / LOG_DIR);
+        GenerateYuzuPath(YuzuPath::NANDDir, yuzu_path / NAND_DIR);
+        GenerateYuzuPath(YuzuPath::ScreenshotsDir, yuzu_path / SCREENSHOTS_DIR);
+        GenerateYuzuPath(YuzuPath::SDMCDir, yuzu_path / SDMC_DIR);
+        GenerateYuzuPath(YuzuPath::ShaderDir, yuzu_path / SHADER_DIR);
+    }
+
+    ~PathManagerImpl() = default;
+
+    void GenerateYuzuPath(YuzuPath yuzu_path, const fs::path& new_path) {
+        void(FS::CreateDir(new_path));
+
+        SetYuzuPathImpl(yuzu_path, new_path);
+    }
+
+    std::unordered_map<YuzuPath, fs::path> yuzu_paths;
+};
+
+std::string PathToUTF8String(const fs::path& path) {
+    const auto utf8_string = path.u8string();
+
+    return std::string{utf8_string.begin(), utf8_string.end()};
+}
+
+bool ValidatePath(const fs::path& path) {
+    if (path.empty()) {
+        LOG_ERROR(Common_Filesystem, "Input path is empty, path={}", PathToUTF8String(path));
+        return false;
+    }
+
+#ifdef _WIN32
+    if (path.u16string().size() >= MAX_PATH) {
+        LOG_ERROR(Common_Filesystem, "Input path is too long, path={}", PathToUTF8String(path));
+        return false;
+    }
+#else
+    if (path.u8string().size() >= MAX_PATH) {
+        LOG_ERROR(Common_Filesystem, "Input path is too long, path={}", PathToUTF8String(path));
+        return false;
+    }
+#endif
+
+    return true;
+}
+
+fs::path ConcatPath(const fs::path& first, const fs::path& second) {
+    const bool second_has_dir_sep = IsDirSeparator(second.u8string().front());
+
+    if (!second_has_dir_sep) {
+        return (first / second).lexically_normal();
+    }
+
+    fs::path concat_path = first;
+    concat_path += second;
+
+    return concat_path.lexically_normal();
+}
+
+fs::path ConcatPathSafe(const fs::path& base, const fs::path& offset) {
+    const auto concatenated_path = ConcatPath(base, offset);
+
+    if (!IsPathSandboxed(base, concatenated_path)) {
+        return base;
+    }
+
+    return concatenated_path;
+}
+
+bool IsPathSandboxed(const fs::path& base, const fs::path& path) {
+    const auto base_string = RemoveTrailingSeparators(base.lexically_normal()).u8string();
+    const auto path_string = RemoveTrailingSeparators(path.lexically_normal()).u8string();
+
+    if (path_string.size() < base_string.size()) {
+        return false;
+    }
+
+    return base_string.compare(0, base_string.size(), path_string, 0, base_string.size()) == 0;
+}
+
+bool IsDirSeparator(char character) {
+    return character == '/' || character == '\\';
+}
+
+bool IsDirSeparator(char8_t character) {
+    return character == u8'/' || character == u8'\\';
+}
+
+fs::path RemoveTrailingSeparators(const fs::path& path) {
+    if (path.empty()) {
+        return path;
+    }
+
+    auto string_path = path.u8string();
+
+    while (IsDirSeparator(string_path.back())) {
+        string_path.pop_back();
+    }
+
+    return fs::path{string_path};
+}
+
+const fs::path& GetYuzuPath(YuzuPath yuzu_path) {
+    return PathManagerImpl::GetInstance().GetYuzuPathImpl(yuzu_path);
+}
+
+std::string GetYuzuPathString(YuzuPath yuzu_path) {
+    return PathToUTF8String(GetYuzuPath(yuzu_path));
+}
+
+void SetYuzuPath(YuzuPath yuzu_path, const fs::path& new_path) {
+    if (!FS::IsDir(new_path)) {
+        LOG_ERROR(Common_Filesystem, "Filesystem object at new_path={} is not a directory",
+                  PathToUTF8String(new_path));
+        return;
+    }
+
+    PathManagerImpl::GetInstance().SetYuzuPathImpl(yuzu_path, new_path);
+}
+
+#ifdef _WIN32
+
+fs::path GetExeDirectory() {
+    wchar_t exe_path[MAX_PATH];
+
+    GetModuleFileNameW(nullptr, exe_path, MAX_PATH);
+
+    if (!exe_path) {
+        LOG_ERROR(Common_Filesystem,
+                  "Failed to get the path to the executable of the current process");
+    }
+
+    return fs::path{exe_path}.parent_path();
+}
+
+fs::path GetAppDataRoamingDirectory() {
+    PWSTR appdata_roaming_path = nullptr;
+
+    SHGetKnownFolderPath(FOLDERID_RoamingAppData, 0, nullptr, &appdata_roaming_path);
+
+    auto fs_appdata_roaming_path = fs::path{appdata_roaming_path};
+
+    CoTaskMemFree(appdata_roaming_path);
+
+    if (fs_appdata_roaming_path.empty()) {
+        LOG_ERROR(Common_Filesystem, "Failed to get the path to the %APPDATA% directory");
+    }
+
+    return fs_appdata_roaming_path;
+}
+
+#else
+
+fs::path GetHomeDirectory() {
+    const char* home_env_var = getenv("HOME");
+
+    if (home_env_var) {
+        return fs::path{home_env_var};
+    }
+
+    LOG_INFO(Common_Filesystem,
+             "$HOME is not defined in the environment variables, "
+             "attempting to query passwd to get the home path of the current user");
+
+    const auto* pw = getpwuid(getuid());
+
+    if (!pw) {
+        LOG_ERROR(Common_Filesystem, "Failed to get the home path of the current user");
+        return {};
+    }
+
+    return fs::path{pw->pw_dir};
+}
+
+fs::path GetDataDirectory(const std::string& env_name) {
+    const char* data_env_var = getenv(env_name.c_str());
+
+    if (data_env_var) {
+        return fs::path{data_env_var};
+    }
+
+    if (env_name == "XDG_DATA_HOME") {
+        return GetHomeDirectory() / ".local/share";
+    } else if (env_name == "XDG_CACHE_HOME") {
+        return GetHomeDirectory() / ".cache";
+    } else if (env_name == "XDG_CONFIG_HOME") {
+        return GetHomeDirectory() / ".config";
+    }
+
+    return {};
+}
+
+#endif
+
+#ifdef __APPLE__
+
+fs::path GetBundleDirectory() {
+    char app_bundle_path[MAXPATHLEN];
+
+    // Get the main bundle for the app
+    CFURLRef bundle_ref = CFBundleCopyBundleURL(CFBundleGetMainBundle());
+    CFStringRef bundle_path = CFURLCopyFileSystemPath(bundle_ref, kCFURLPOSIXPathStyle);
+
+    CFStringGetFileSystemRepresentation(bundle_path, app_bundle_path, sizeof(app_bundle_path));
+
+    CFRelease(bundle_ref);
+    CFRelease(bundle_path);
+
+    return fs::path{app_bundle_path};
+}
+
+#endif
+
+// vvvvvvvvvv Deprecated vvvvvvvvvv //
+
+std::string_view RemoveTrailingSlash(std::string_view path) {
+    if (path.empty()) {
+        return path;
+    }
+
+    if (path.back() == '\\' || path.back() == '/') {
+        path.remove_suffix(1);
+        return path;
+    }
+
+    return path;
+}
+
+std::vector<std::string> SplitPathComponents(std::string_view filename) {
+    std::string copy(filename);
+    std::replace(copy.begin(), copy.end(), '\\', '/');
+    std::vector<std::string> out;
+
+    std::stringstream stream(copy);
+    std::string item;
+    while (std::getline(stream, item, '/')) {
+        out.push_back(std::move(item));
+    }
+
+    return out;
+}
+
+std::string SanitizePath(std::string_view path_, DirectorySeparator directory_separator) {
+    std::string path(path_);
+    char type1 = directory_separator == DirectorySeparator::BackwardSlash ? '/' : '\\';
+    char type2 = directory_separator == DirectorySeparator::BackwardSlash ? '\\' : '/';
+
+    if (directory_separator == DirectorySeparator::PlatformDefault) {
+#ifdef _WIN32
+        type1 = '/';
+        type2 = '\\';
+#endif
+    }
+
+    std::replace(path.begin(), path.end(), type1, type2);
+
+    auto start = path.begin();
+#ifdef _WIN32
+    // allow network paths which start with a double backslash (e.g. \\server\share)
+    if (start != path.end())
+        ++start;
+#endif
+    path.erase(std::unique(start, path.end(),
+                           [type2](char c1, char c2) { return c1 == type2 && c2 == type2; }),
+               path.end());
+    return std::string(RemoveTrailingSlash(path));
+}
+
+std::string_view GetParentPath(std::string_view path) {
+    const auto name_bck_index = path.rfind('\\');
+    const auto name_fwd_index = path.rfind('/');
+    std::size_t name_index;
+
+    if (name_bck_index == std::string_view::npos || name_fwd_index == std::string_view::npos) {
+        name_index = std::min(name_bck_index, name_fwd_index);
+    } else {
+        name_index = std::max(name_bck_index, name_fwd_index);
+    }
+
+    return path.substr(0, name_index);
+}
+
+std::string_view GetPathWithoutTop(std::string_view path) {
+    if (path.empty()) {
+        return path;
+    }
+
+    while (path[0] == '\\' || path[0] == '/') {
+        path.remove_prefix(1);
+        if (path.empty()) {
+            return path;
+        }
+    }
+
+    const auto name_bck_index = path.find('\\');
+    const auto name_fwd_index = path.find('/');
+    return path.substr(std::min(name_bck_index, name_fwd_index) + 1);
+}
+
+std::string_view GetFilename(std::string_view path) {
+    const auto name_index = path.find_last_of("\\/");
+
+    if (name_index == std::string_view::npos) {
+        return {};
+    }
+
+    return path.substr(name_index + 1);
+}
+
+std::string_view GetExtensionFromFilename(std::string_view name) {
+    const std::size_t index = name.rfind('.');
+
+    if (index == std::string_view::npos) {
+        return {};
+    }
+
+    return name.substr(index + 1);
+}
+
+} // namespace Common::FS

src/common/fs/path_util.h

@@ -0,0 +1,309 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <filesystem>
+#include <vector>
+
+#include "common/fs/fs_util.h"
+
+namespace Common::FS {
+
+enum class YuzuPath {
+    YuzuDir,        // Where yuzu stores its data.
+    CacheDir,       // Where cached filesystem data is stored.
+    ConfigDir,      // Where config files are stored.
+    DumpDir,        // Where dumped data is stored.
+    KeysDir,        // Where key files are stored.
+    LoadDir,        // Where cheat/mod files are stored.
+    LogDir,         // Where log files are stored.
+    NANDDir,        // Where the emulated NAND is stored.
+    ScreenshotsDir, // Where yuzu screenshots are stored.
+    SDMCDir,        // Where the emulated SDMC is stored.
+    ShaderDir,      // Where shaders are stored.
+};
+
+/**
+ * Converts a filesystem path to a UTF-8 encoded std::string.
+ *
+ * @param path Filesystem path
+ *
+ * @returns UTF-8 encoded std::string.
+ */
+[[nodiscard]] std::string PathToUTF8String(const std::filesystem::path& path);
+
+/**
+ * Validates a given path.
+ *
+ * A given path is valid if it meets these conditions:
+ * - The path is not empty
+ * - The path is not too long
+ *
+ * @param path Filesystem path
+ *
+ * @returns True if the path is valid, false otherwise.
+ */
+[[nodiscard]] bool ValidatePath(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] bool ValidatePath(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return ValidatePath(ToU8String(path));
+    } else {
+        return ValidatePath(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Concatenates two filesystem paths together.
+ *
+ * This is needed since the following occurs when using std::filesystem::path's operator/:
+ * first: "/first/path"
+ * second: "/second/path" (Note that the second path has a directory separator in the front)
+ * first / second yields "/second/path" when the desired result is first/path/second/path
+ *
+ * @param first First filesystem path
+ * @param second Second filesystem path
+ *
+ * @returns A concatenated filesystem path.
+ */
+[[nodiscard]] std::filesystem::path ConcatPath(const std::filesystem::path& first,
+                                               const std::filesystem::path& second);
+
+#ifdef _WIN32
+template <typename Path1, typename Path2>
+[[nodiscard]] std::filesystem::path ConcatPath(const Path1& first, const Path2& second) {
+    using ValueType1 = typename Path1::value_type;
+    using ValueType2 = typename Path2::value_type;
+    if constexpr (IsChar<ValueType1> && IsChar<ValueType2>) {
+        return ConcatPath(ToU8String(first), ToU8String(second));
+    } else if constexpr (IsChar<ValueType1> && !IsChar<ValueType2>) {
+        return ConcatPath(ToU8String(first), second);
+    } else if constexpr (!IsChar<ValueType1> && IsChar<ValueType2>) {
+        return ConcatPath(first, ToU8String(second));
+    } else {
+        return ConcatPath(std::filesystem::path{first}, std::filesystem::path{second});
+    }
+}
+#endif
+
+/**
+ * Safe variant of ConcatPath that takes in a base path and an offset path from the given base path.
+ *
+ * If ConcatPath(base, offset) resolves to a path that is sandboxed within the base path,
+ * this will return the concatenated path. Otherwise this will return the base path.
+ *
+ * @param base Base filesystem path
+ * @param offset Offset filesystem path
+ *
+ * @returns A concatenated filesystem path if it is within the base path,
+ *          returns the base path otherwise.
+ */
+[[nodiscard]] std::filesystem::path ConcatPathSafe(const std::filesystem::path& base,
+                                                   const std::filesystem::path& offset);
+
+#ifdef _WIN32
+template <typename Path1, typename Path2>
+[[nodiscard]] std::filesystem::path ConcatPathSafe(const Path1& base, const Path2& offset) {
+    using ValueType1 = typename Path1::value_type;
+    using ValueType2 = typename Path2::value_type;
+    if constexpr (IsChar<ValueType1> && IsChar<ValueType2>) {
+        return ConcatPathSafe(ToU8String(base), ToU8String(offset));
+    } else if constexpr (IsChar<ValueType1> && !IsChar<ValueType2>) {
+        return ConcatPathSafe(ToU8String(base), offset);
+    } else if constexpr (!IsChar<ValueType1> && IsChar<ValueType2>) {
+        return ConcatPathSafe(base, ToU8String(offset));
+    } else {
+        return ConcatPathSafe(std::filesystem::path{base}, std::filesystem::path{offset});
+    }
+}
+#endif
+
+/**
+ * Checks whether a given path is sandboxed within a given base path.
+ *
+ * @param base Base filesystem path
+ * @param path Filesystem path
+ *
+ * @returns True if the given path is sandboxed within the given base path, false otherwise.
+ */
+[[nodiscard]] bool IsPathSandboxed(const std::filesystem::path& base,
+                                   const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path1, typename Path2>
+[[nodiscard]] bool IsPathSandboxed(const Path1& base, const Path2& path) {
+    using ValueType1 = typename Path1::value_type;
+    using ValueType2 = typename Path2::value_type;
+    if constexpr (IsChar<ValueType1> && IsChar<ValueType2>) {
+        return IsPathSandboxed(ToU8String(base), ToU8String(path));
+    } else if constexpr (IsChar<ValueType1> && !IsChar<ValueType2>) {
+        return IsPathSandboxed(ToU8String(base), path);
+    } else if constexpr (!IsChar<ValueType1> && IsChar<ValueType2>) {
+        return IsPathSandboxed(base, ToU8String(path));
+    } else {
+        return IsPathSandboxed(std::filesystem::path{base}, std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Checks if a character is a directory separator (either a forward slash or backslash).
+ *
+ * @param character Character
+ *
+ * @returns True if the character is a directory separator, false otherwise.
+ */
+[[nodiscard]] bool IsDirSeparator(char character);
+
+/**
+ * Checks if a character is a directory separator (either a forward slash or backslash).
+ *
+ * @param character Character
+ *
+ * @returns True if the character is a directory separator, false otherwise.
+ */
+[[nodiscard]] bool IsDirSeparator(char8_t character);
+
+/**
+ * Removes any trailing directory separators if they exist in the given path.
+ *
+ * @param path Filesystem path
+ *
+ * @returns The filesystem path without any trailing directory separators.
+ */
+[[nodiscard]] std::filesystem::path RemoveTrailingSeparators(const std::filesystem::path& path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] std::filesystem::path RemoveTrailingSeparators(const Path& path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        return RemoveTrailingSeparators(ToU8String(path));
+    } else {
+        return RemoveTrailingSeparators(std::filesystem::path{path});
+    }
+}
+#endif
+
+/**
+ * Gets the filesystem path associated with the YuzuPath enum.
+ *
+ * @param yuzu_path YuzuPath enum
+ *
+ * @returns The filesystem path associated with the YuzuPath enum.
+ */
+[[nodiscard]] const std::filesystem::path& GetYuzuPath(YuzuPath yuzu_path);
+
+/**
+ * Gets the filesystem path associated with the YuzuPath enum as a UTF-8 encoded std::string.
+ *
+ * @param yuzu_path YuzuPath enum
+ *
+ * @returns The filesystem path associated with the YuzuPath enum as a UTF-8 encoded std::string.
+ */
+[[nodiscard]] std::string GetYuzuPathString(YuzuPath yuzu_path);
+
+/**
+ * Sets a new filesystem path associated with the YuzuPath enum.
+ * If the filesystem object at new_path is not a directory, this function will not do anything.
+ *
+ * @param yuzu_path YuzuPath enum
+ * @param new_path New filesystem path
+ */
+void SetYuzuPath(YuzuPath yuzu_path, const std::filesystem::path& new_path);
+
+#ifdef _WIN32
+template <typename Path>
+[[nodiscard]] void SetYuzuPath(YuzuPath yuzu_path, const Path& new_path) {
+    if constexpr (IsChar<typename Path::value_type>) {
+        SetYuzuPath(yuzu_path, ToU8String(new_path));
+    } else {
+        SetYuzuPath(yuzu_path, std::filesystem::path{new_path});
+    }
+}
+#endif
+
+#ifdef _WIN32
+
+/**
+ * Gets the path of the directory containing the executable of the current process.
+ *
+ * @returns The path of the directory containing the executable of the current process.
+ */
+[[nodiscard]] std::filesystem::path GetExeDirectory();
+
+/**
+ * Gets the path of the current user's %APPDATA% directory (%USERPROFILE%/AppData/Roaming).
+ *
+ * @returns The path of the current user's %APPDATA% directory.
+ */
+[[nodiscard]] std::filesystem::path GetAppDataRoamingDirectory();
+
+#else
+
+/**
+ * Gets the path of the directory specified by the #HOME environment variable.
+ * If $HOME is not defined, it will attempt to query the user database in passwd instead.
+ *
+ * @returns The path of the current user's home directory.
+ */
+[[nodiscard]] std::filesystem::path GetHomeDirectory();
+
+/**
+ * Gets the relevant paths for yuzu to store its data based on the given XDG environment variable.
+ * See https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
+ * Defaults to $HOME/.local/share for main application data,
+ * $HOME/.cache for cached data, and $HOME/.config for configuration files.
+ *
+ * @param env_name XDG environment variable name
+ *
+ * @returns The path where yuzu should store its data.
+ */
+[[nodiscard]] std::filesystem::path GetDataDirectory(const std::string& env_name);
+
+#endif
+
+#ifdef __APPLE__
+
+[[nodiscard]] std::filesystem::path GetBundleDirectory();
+
+#endif
+
+// vvvvvvvvvv Deprecated vvvvvvvvvv //
+
+// Removes the final '/' or '\' if one exists
+[[nodiscard]] std::string_view RemoveTrailingSlash(std::string_view path);
+
+enum class DirectorySeparator {
+    ForwardSlash,
+    BackwardSlash,
+    PlatformDefault,
+};
+
+// Splits the path on '/' or '\' and put the components into a vector
+// i.e. "C:\Users\Yuzu\Documents\save.bin" becomes {"C:", "Users", "Yuzu", "Documents", "save.bin" }
+[[nodiscard]] std::vector<std::string> SplitPathComponents(std::string_view filename);
+
+// Removes trailing slash, makes all '\\' into '/', and removes duplicate '/'. Makes '/' into '\\'
+// depending if directory_separator is BackwardSlash or PlatformDefault and running on windows
+[[nodiscard]] std::string SanitizePath(
+    std::string_view path,
+    DirectorySeparator directory_separator = DirectorySeparator::ForwardSlash);
+
+// Gets all of the text up to the last '/' or '\' in the path.
+[[nodiscard]] std::string_view GetParentPath(std::string_view path);
+
+// Gets all of the text after the first '/' or '\' in the path.
+[[nodiscard]] std::string_view GetPathWithoutTop(std::string_view path);
+
+// Gets the filename of the path
+[[nodiscard]] std::string_view GetFilename(std::string_view path);
+
+// Gets the extension of the filename
+[[nodiscard]] std::string_view GetExtensionFromFilename(std::string_view name);
+
+} // namespace Common::FS