8b4d5aeb4f
This also covers std::span, which does not have a const iterator. Also renames IsSTLContainer to IsContiguousContainer to explicitly convey its semantics.
459 lines
16 KiB
C++
459 lines
16 KiB
C++
// SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#pragma once
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#include <cstdio>
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#include <filesystem>
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#include <span>
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#include <type_traits>
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#include "common/concepts.h"
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#include "common/fs/fs_types.h"
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#include "common/fs/fs_util.h"
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namespace Common::FS {
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enum class SeekOrigin {
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SetOrigin, // Seeks from the start of the file.
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CurrentPosition, // Seeks from the current file pointer position.
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End, // Seeks from the end of the file.
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};
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/**
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* Opens a file stream at path with the specified open mode.
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*
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* @param file_stream Reference to file stream
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* @param path Filesystem path
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* @param open_mode File stream open mode
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*/
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template <typename FileStream>
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void OpenFileStream(FileStream& file_stream, const std::filesystem::path& path,
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std::ios_base::openmode open_mode) {
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file_stream.open(path, open_mode);
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}
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#ifdef _WIN32
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template <typename FileStream, typename Path>
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void OpenFileStream(FileStream& file_stream, const Path& path, std::ios_base::openmode open_mode) {
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if constexpr (IsChar<typename Path::value_type>) {
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file_stream.open(ToU8String(path), open_mode);
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} else {
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file_stream.open(std::filesystem::path{path}, open_mode);
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}
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}
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#endif
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/**
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* Reads an entire file at path and returns a string of the contents read from the file.
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* If the filesystem object at path is not a regular file, this function returns an empty string.
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*
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* @param path Filesystem path
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* @param type File type
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*
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* @returns A string of the contents read from the file.
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*/
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[[nodiscard]] std::string ReadStringFromFile(const std::filesystem::path& path, FileType type);
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#ifdef _WIN32
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template <typename Path>
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[[nodiscard]] std::string ReadStringFromFile(const Path& path, FileType type) {
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if constexpr (IsChar<typename Path::value_type>) {
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return ReadStringFromFile(ToU8String(path), type);
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} else {
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return ReadStringFromFile(std::filesystem::path{path}, type);
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}
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}
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#endif
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/**
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* Writes a string to a file at path and returns the number of characters successfully written.
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* If a file already exists at path, its contents will be erased.
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* If a file does not exist at path, it creates and opens a new empty file for writing.
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* If the filesystem object at path exists and is not a regular file, this function returns 0.
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*
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* @param path Filesystem path
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* @param type File type
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*
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* @returns Number of characters successfully written.
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*/
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[[nodiscard]] size_t WriteStringToFile(const std::filesystem::path& path, FileType type,
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std::string_view string);
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#ifdef _WIN32
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template <typename Path>
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[[nodiscard]] size_t WriteStringToFile(const Path& path, FileType type, std::string_view string) {
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if constexpr (IsChar<typename Path::value_type>) {
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return WriteStringToFile(ToU8String(path), type, string);
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} else {
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return WriteStringToFile(std::filesystem::path{path}, type, string);
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}
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}
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#endif
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/**
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* Appends a string to a file at path and returns the number of characters successfully written.
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* If a file does not exist at path, it creates and opens a new empty file for appending.
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* If the filesystem object at path exists and is not a regular file, this function returns 0.
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*
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* @param path Filesystem path
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* @param type File type
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*
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* @returns Number of characters successfully written.
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*/
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[[nodiscard]] size_t AppendStringToFile(const std::filesystem::path& path, FileType type,
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std::string_view string);
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#ifdef _WIN32
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template <typename Path>
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[[nodiscard]] size_t AppendStringToFile(const Path& path, FileType type, std::string_view string) {
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if constexpr (IsChar<typename Path::value_type>) {
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return AppendStringToFile(ToU8String(path), type, string);
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} else {
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return AppendStringToFile(std::filesystem::path{path}, type, string);
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}
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}
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#endif
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class IOFile final {
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public:
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IOFile();
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explicit IOFile(const std::string& path, FileAccessMode mode,
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FileType type = FileType::BinaryFile,
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FileShareFlag flag = FileShareFlag::ShareReadOnly);
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explicit IOFile(std::string_view path, FileAccessMode mode,
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FileType type = FileType::BinaryFile,
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FileShareFlag flag = FileShareFlag::ShareReadOnly);
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/**
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* An IOFile is a lightweight wrapper on C Library file operations.
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* Automatically closes an open file on the destruction of an IOFile object.
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*
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* @param path Filesystem path
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* @param mode File access mode
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* @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
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* @param flag (Windows only) File-share access flag, default is ShareReadOnly
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*/
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explicit IOFile(const std::filesystem::path& path, FileAccessMode mode,
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FileType type = FileType::BinaryFile,
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FileShareFlag flag = FileShareFlag::ShareReadOnly);
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~IOFile();
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IOFile(const IOFile&) = delete;
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IOFile& operator=(const IOFile&) = delete;
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IOFile(IOFile&& other) noexcept;
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IOFile& operator=(IOFile&& other) noexcept;
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/**
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* Gets the path of the file.
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*
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* @returns The path of the file.
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*/
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[[nodiscard]] std::filesystem::path GetPath() const;
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/**
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* Gets the access mode of the file.
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*
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* @returns The access mode of the file.
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*/
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[[nodiscard]] FileAccessMode GetAccessMode() const;
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/**
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* Gets the type of the file.
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*
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* @returns The type of the file.
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*/
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[[nodiscard]] FileType GetType() const;
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/**
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* Opens a file at path with the specified file access mode.
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* This function behaves differently depending on the FileAccessMode.
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* These behaviors are documented in each enum value of FileAccessMode.
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*
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* @param path Filesystem path
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* @param mode File access mode
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* @param type File type, default is BinaryFile. Use TextFile to open the file as a text file
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* @param flag (Windows only) File-share access flag, default is ShareReadOnly
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*/
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void Open(const std::filesystem::path& path, FileAccessMode mode,
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FileType type = FileType::BinaryFile,
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FileShareFlag flag = FileShareFlag::ShareReadOnly);
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#ifdef _WIN32
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template <typename Path>
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void Open(const Path& path, FileAccessMode mode, FileType type = FileType::BinaryFile,
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FileShareFlag flag = FileShareFlag::ShareReadOnly) {
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using ValueType = typename Path::value_type;
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if constexpr (IsChar<ValueType>) {
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Open(ToU8String(path), mode, type, flag);
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} else {
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Open(std::filesystem::path{path}, mode, type, flag);
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}
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}
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#endif
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/// Closes the file if it is opened.
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void Close();
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/**
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* Checks whether the file is open.
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* Use this to check whether the calls to Open() or Close() succeeded.
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*
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* @returns True if the file is open, false otherwise.
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*/
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[[nodiscard]] bool IsOpen() const;
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/**
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* Helper function which deduces the value type of a contiguous STL container used in ReadSpan.
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* If T is not a contiguous container as defined by the concept IsContiguousContainer, this
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* calls ReadObject and T must be a trivially copyable object.
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*
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* See ReadSpan for more details if T is a contiguous container.
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* See ReadObject for more details if T is a trivially copyable object.
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*
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* @tparam T Contiguous container or trivially copyable object
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*
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* @param data Container of T::value_type data or reference to object
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*
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* @returns Count of T::value_type data or objects successfully read.
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*/
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template <typename T>
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[[nodiscard]] size_t Read(T& data) const {
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if constexpr (IsContiguousContainer<T>) {
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using ContiguousType = typename T::value_type;
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static_assert(std::is_trivially_copyable_v<ContiguousType>,
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"Data type must be trivially copyable.");
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return ReadSpan<ContiguousType>(data);
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} else {
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return ReadObject(data) ? 1 : 0;
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}
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}
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/**
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* Helper function which deduces the value type of a contiguous STL container used in WriteSpan.
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* If T is not a contiguous STL container as defined by the concept IsContiguousContainer, this
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* calls WriteObject and T must be a trivially copyable object.
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*
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* See WriteSpan for more details if T is a contiguous container.
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* See WriteObject for more details if T is a trivially copyable object.
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*
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* @tparam T Contiguous container or trivially copyable object
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*
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* @param data Container of T::value_type data or const reference to object
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*
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* @returns Count of T::value_type data or objects successfully written.
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*/
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template <typename T>
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[[nodiscard]] size_t Write(const T& data) const {
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if constexpr (IsContiguousContainer<T>) {
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using ContiguousType = typename T::value_type;
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static_assert(std::is_trivially_copyable_v<ContiguousType>,
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"Data type must be trivially copyable.");
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return WriteSpan<ContiguousType>(data);
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} else {
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static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
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return WriteObject(data) ? 1 : 0;
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}
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}
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/**
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* Reads a span of T data from a file sequentially.
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* This function reads from the current position of the file pointer and
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* advances it by the (count of T * sizeof(T)) bytes successfully read.
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*
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* Failures occur when:
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* - The file is not open
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* - The opened file lacks read permissions
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* - Attempting to read beyond the end-of-file
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*
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* @tparam T Data type
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*
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* @param data Span of T data
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*
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* @returns Count of T data successfully read.
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*/
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template <typename T>
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[[nodiscard]] size_t ReadSpan(std::span<T> data) const {
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static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
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if (!IsOpen()) {
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return 0;
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}
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return std::fread(data.data(), sizeof(T), data.size(), file);
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}
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/**
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* Writes a span of T data to a file sequentially.
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* This function writes from the current position of the file pointer and
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* advances it by the (count of T * sizeof(T)) bytes successfully written.
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*
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* Failures occur when:
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* - The file is not open
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* - The opened file lacks write permissions
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*
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* @tparam T Data type
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*
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* @param data Span of T data
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*
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* @returns Count of T data successfully written.
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*/
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template <typename T>
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[[nodiscard]] size_t WriteSpan(std::span<const T> data) const {
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static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
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if (!IsOpen()) {
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return 0;
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}
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return std::fwrite(data.data(), sizeof(T), data.size(), file);
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}
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/**
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* Reads a T object from a file sequentially.
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* This function reads from the current position of the file pointer and
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* advances it by the sizeof(T) bytes successfully read.
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*
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* Failures occur when:
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* - The file is not open
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* - The opened file lacks read permissions
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* - Attempting to read beyond the end-of-file
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*
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* @tparam T Data type
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*
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* @param object Reference to object
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*
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* @returns True if the object is successfully read from the file, false otherwise.
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*/
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template <typename T>
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[[nodiscard]] bool ReadObject(T& object) const {
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static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
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static_assert(!std::is_pointer_v<T>, "T must not be a pointer to an object.");
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if (!IsOpen()) {
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return false;
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}
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return std::fread(&object, sizeof(T), 1, file) == 1;
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}
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/**
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* Writes a T object to a file sequentially.
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* This function writes from the current position of the file pointer and
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* advances it by the sizeof(T) bytes successfully written.
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*
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* Failures occur when:
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* - The file is not open
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* - The opened file lacks write permissions
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*
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* @tparam T Data type
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*
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* @param object Const reference to object
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*
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* @returns True if the object is successfully written to the file, false otherwise.
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*/
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template <typename T>
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[[nodiscard]] bool WriteObject(const T& object) const {
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static_assert(std::is_trivially_copyable_v<T>, "Data type must be trivially copyable.");
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static_assert(!std::is_pointer_v<T>, "T must not be a pointer to an object.");
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if (!IsOpen()) {
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return false;
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}
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return std::fwrite(&object, sizeof(T), 1, file) == 1;
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}
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/**
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* Specialized function to read a string of a given length from a file sequentially.
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* This function writes from the current position of the file pointer and
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* advances it by the number of characters successfully read.
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* The size of the returned string may not match length if not all bytes are successfully read.
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*
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* @param length Length of the string
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*
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* @returns A string read from the file.
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*/
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[[nodiscard]] std::string ReadString(size_t length) const;
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/**
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* Specialized function to write a string to a file sequentially.
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* This function writes from the current position of the file pointer and
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* advances it by the number of characters successfully written.
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*
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* @param string Span of const char backed std::string or std::string_view
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*
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* @returns Number of characters successfully written.
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*/
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[[nodiscard]] size_t WriteString(std::span<const char> string) const;
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/**
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* Attempts to flush any unwritten buffered data into the file.
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*
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* @returns True if the flush was successful, false otherwise.
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*/
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bool Flush() const;
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/**
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* Attempts to commit the file into the disk.
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* Note that this is an expensive operation as this forces the operating system to write
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* the contents of the file associated with the file descriptor into the disk.
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*
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* @returns True if the commit was successful, false otherwise.
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*/
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bool Commit() const;
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/**
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* Resizes the file to a given size.
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* If the file is resized to a smaller size, the remainder of the file is discarded.
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* If the file is resized to a larger size, the new area appears as if zero-filled.
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*
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* Failures occur when:
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* - The file is not open
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*
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* @param size File size in bytes
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*
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* @returns True if the file resize succeeded, false otherwise.
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*/
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[[nodiscard]] bool SetSize(u64 size) const;
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/**
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* Gets the size of the file.
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*
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* Failures occur when:
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* - The file is not open
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*
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* @returns The file size in bytes of the file. Returns 0 on failure.
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*/
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[[nodiscard]] u64 GetSize() const;
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/**
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* Moves the current position of the file pointer with the specified offset and seek origin.
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*
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* @param offset Offset from seek origin
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* @param origin Seek origin
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*
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* @returns True if the file pointer has moved to the specified offset, false otherwise.
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*/
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[[nodiscard]] bool Seek(s64 offset, SeekOrigin origin = SeekOrigin::SetOrigin) const;
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/**
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* Gets the current position of the file pointer.
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*
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* @returns The current position of the file pointer.
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*/
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[[nodiscard]] s64 Tell() const;
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private:
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std::filesystem::path file_path;
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FileAccessMode file_access_mode{};
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FileType file_type{};
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std::FILE* file = nullptr;
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};
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} // namespace Common::FS
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