axmol/core/platform/FileUtils.h

/****************************************************************************
Copyright (c) 2010-2013 cocos2d-x.org
Copyright (c) 2013-2016 Chukong Technologies Inc.
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
Copyright (c) 2022-2023 Bytedance Inc.

https://axmolengine.github.io/

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#ifndef __AX_FILEUTILS_H__
#define __AX_FILEUTILS_H__

#include <string>
#include <vector>
#include <unordered_map>
#include <type_traits>
#include <mutex>
#include <memory>

#include "platform/FileStream.h"
#include "platform/PlatformMacros.h"
#include "base/Types.h"
#include "base/Value.h"
#include "base/Data.h"
#include "base/AsyncTaskPool.h"
#include "base/Scheduler.h"
#include "base/Director.h"

#define AX_CONTENT_DIR "Content/"
#define AX_CONTENT_DIR_LEN (sizeof("Content/") - 1)

NS_AX_BEGIN

/**
 * @addtogroup platform
 * @{
 */

class ResizableBuffer
{
public:
    virtual ~ResizableBuffer() {}
    virtual void resize(size_t size) = 0;
    virtual void* buffer() const     = 0;
    virtual size_t size() const      = 0;
};

template <typename T, typename Enable = void>
struct is_resizable_container : std::false_type
{};

template <typename... Ts>
struct is_resizable_container_helper
{};

template <typename T>
struct is_resizable_container<T,
                              std::conditional_t<false,
                                                 is_resizable_container_helper<typename T::value_type,
                                                                               decltype(std::declval<T>().size()),
                                                                               decltype(std::declval<T>().resize(0)),
                                                                               decltype(std::declval<T>().data())>,
                                                 void>> : public std::true_type
{};

template <typename _T>
inline constexpr bool is_resizable_container_v = is_resizable_container<_T>::value;

template <typename T>
class ResizableBufferAdapter : public ResizableBuffer
{
    T* _buffer;

public:
    explicit ResizableBufferAdapter(T* buffer) : _buffer(buffer) {}
    virtual void resize(size_t size) override
    {
        _buffer->resize((size + sizeof(typename T::value_type) - 1) / sizeof(typename T::value_type));
    }
    virtual void* buffer() const override { return _buffer->data(); }
    virtual size_t size() const override { return _buffer->size() * sizeof(typename T::value_type); }
};

/** Helper class to handle file operations. */
class AX_DLL FileUtils
{
public:
    /**
     *  Gets the instance of FileUtils.
     */
    static FileUtils* getInstance();

    /**
     *  Destroys the instance of FileUtils.
     */
    static void destroyInstance();

    /**
     * You can inherit from platform dependent implementation of FileUtils, such as FileUtilsAndroid,
     * and use this function to set delegate, then FileUtils will invoke delegate's implementation.
     * For example, your resources are encrypted, so you need to decrypt it after reading data from
     * resources, then you can implement all getXXX functions, and engine will invoke your own getXX
     * functions when reading data of resources.
     *
     * If you don't want to system default implementation after setting delegate, you can just pass nullptr
     * to this function.
     *
     * @warning It will delete previous delegate
     * @lua NA
     */
    static void setDelegate(FileUtils* delegate);

    /**
     *  The destructor of FileUtils.
     * @js NA
     * @lua NA
     */
    virtual ~FileUtils();

    /**
     *  Purges full path caches.
     */
    virtual void purgeCachedEntries();

    /**
     *  Gets string from a file.
     */
    virtual std::string getStringFromFile(std::string_view filename) const;

    /**
     * Gets string from a file, async off the main cocos thread
     *
     * @param path filepath for the string to be read. Can be relative or absolute path
     * @param callback Function that will be called when file is read. Will be called
     * on the main cocos thread.
     */
    virtual void getStringFromFile(std::string_view path, std::function<void(std::string)> callback) const;

    /**
     *  Creates binary data from a file.
     *  @return A data object.
     */
    virtual Data getDataFromFile(std::string_view filename) const;

    /**
     * Gets a binary data object from a file, async off the main cocos thread.
     *
     * @param filename filepath for the data to be read. Can be relative or absolute path
     * @param callback Function that will be called when file is read. Will be called
     * on the main cocos thread.
     */
    virtual void getDataFromFile(std::string_view filename, std::function<void(Data)> callback) const;

    enum class Status
    {
        OK                 = 0,
        NotExists          = 1,  // File not exists
        OpenFailed         = 2,  // Open file failed.
        ReadFailed         = 3,  // Read failed
        NotInitialized     = 4,  // FileUtils is not initializes
        TooLarge           = 5,  // The file is too large (great than 2^32-1)
        ObtainSizeFailed   = 6,  // Failed to obtain the file size.
        NotRegularFileType = 7   // File type is not S_IFREG
    };

    /**
     *  Gets whole file contents as string from a file.
     *
     *  Unlike getStringFromFile, these getContents methods:
     *      - read file in binary mode (does not convert CRLF to LF).
     *      - does not truncate the string when '\0' is found (returned string of getContents may have '\0' in the
     * middle.).
     *
     *  The template version of can accept ax::Data, std::basic_string and std::vector.
     *
     *  @code
     *  std::string sbuf;
     *  FileUtils::getInstance()->getContents("path/to/file", &sbuf);
     *
     *  std::vector<int> vbuf;
     *  FileUtils::getInstance()->getContents("path/to/file", &vbuf);
     *
     *  Data dbuf;
     *  FileUtils::getInstance()->getContents("path/to/file", &dbuf);
     *  @endcode
     *
     *  Note: if you read to std::vector<T> and std::basic_string<T> where T is not 8 bit type,
     *  you may get 0 ~ sizeof(T)-1 bytes padding.
     *
     *  - To write a new buffer class works with getContents, just extend ResizableBuffer.
     *  - To write a adapter for existing class, write a specialized ResizableBufferAdapter for that class, see follow
     * code.
     *
     *  @code
     *  NS_AX_BEGIN // ResizableBufferAdapter needed in cocos2d namespace.
     *  template<>
     *  class ResizableBufferAdapter<AlreadyExistsBuffer> : public ResizableBuffer {
     *  public:
     *      ResizableBufferAdapter(AlreadyExistsBuffer* buffer)  {
     *          // your code here
     *      }
     *      virtual void resize(size_t size) override  {
     *          // your code here
     *      }
     *      virtual void* buffer() const override {
     *          // your code here
     *      }
     *  NS_AX_END
     *  @endcode
     *
     *  @param[in]  filename The resource file name which contains the path.
     *  @param[out] buffer The buffer where the file contents are store to.
     *  @return Returns:
     *      - Status::OK when there is no error, the buffer is filled with the contents of file.
     *      - Status::NotExists when file not exists, the buffer will not changed.
     *      - Status::OpenFailed when cannot open file, the buffer will not changed.
     *      - Status::ReadFailed when read end up before read whole, the buffer will fill with already read bytes.
     *      - Status::NotInitialized when FileUtils is not initializes, the buffer will not changed.
     *      - Status::TooLarge when there file to be read is too large (> 2^32-1), the buffer will not changed.
     *      - Status::ObtainSizeFailed when failed to obtain the file size, the buffer will not changed.
     */
    template <typename T, typename Enable = std::enable_if_t<is_resizable_container_v<T>>>
    Status getContents(std::string_view filename, T* buffer) const
    {
        ResizableBufferAdapter<T> buf(buffer);
        return getContents(filename, static_cast<ResizableBuffer*>(&buf));
    }
    virtual Status getContents(std::string_view filename, ResizableBuffer* buffer) const;

    /** Returns the fullpath for a given filename.

     First it will try to get a new filename from the "filenameLookup" dictionary.
     If a new filename can't be found on the dictionary, it will use the original filename.
     Then it will try to obtain the full path of the filename using the FileUtils search rules: resolutions, and search
     paths. The file search is based on the array element order of search paths and resolution directories.

     For instance:

         We set two elements("/mnt/sdcard/", "internal_dir/") to search paths vector by setSearchPaths,

        If we have a file named 'sprite.png', the mapping in fileLookup dictionary contains `key: sprite.png -> value:
     sprite.pvr.gz`. Firstly, it will replace 'sprite.png' with 'sprite.pvr.gz', then searching the file sprite.pvr.gz
     as follows:

             /mnt/sdcard/resources-ipadhd/sprite.pvr.gz      (if not found, search next)
             /mnt/sdcard/resources-ipad/sprite.pvr.gz        (if not found, search next)
             /mnt/sdcard/resources-iphonehd/sprite.pvr.gz    (if not found, search next)
             /mnt/sdcard/sprite.pvr.gz                       (if not found, search next)
             internal_dir/resources-ipadhd/sprite.pvr.gz     (if not found, search next)
             internal_dir/resources-ipad/sprite.pvr.gz       (if not found, search next)
             internal_dir/resources-iphonehd/sprite.pvr.gz   (if not found, search next)
             internal_dir/sprite.pvr.gz                      (if not found, return "sprite.png")

        If the filename contains relative path like "gamescene/uilayer/sprite.png",
        and the mapping in fileLookup dictionary contains `key: gamescene/uilayer/sprite.png -> value:
     gamescene/uilayer/sprite.pvr.gz`. The file search order will be:

             /mnt/sdcard/gamescene/uilayer/resources-ipadhd/sprite.pvr.gz      (if not found, search next)
             /mnt/sdcard/gamescene/uilayer/resources-ipad/sprite.pvr.gz        (if not found, search next)
             /mnt/sdcard/gamescene/uilayer/resources-iphonehd/sprite.pvr.gz    (if not found, search next)
             /mnt/sdcard/gamescene/uilayer/sprite.pvr.gz                       (if not found, search next)
             internal_dir/gamescene/uilayer/resources-ipadhd/sprite.pvr.gz     (if not found, search next)
             internal_dir/gamescene/uilayer/resources-ipad/sprite.pvr.gz       (if not found, search next)
             internal_dir/gamescene/uilayer/resources-iphonehd/sprite.pvr.gz   (if not found, search next)
             internal_dir/gamescene/uilayer/sprite.pvr.gz                      (if not found, return
     "gamescene/uilayer/sprite.png")

     If the new file can't be found on the file system, it will return the parameter filename directly.

     This method was added to simplify multiplatform support. Whether you are using cocos2d-js or any cross-compilation
     toolchain like StellaSDK or Apportable, you might need to load different resources for a given file in the
     different platforms.

     @since v2.1
     */
    virtual std::string fullPathForFilename(std::string_view filename) const;

    /**
     *  Gets full path from a file name and the path of the relative file.
     *  @param filename The file name.
     *  @param relativeFile The path of the relative file.
     *  @return The full path.
     *          e.g. filename: hello.png, pszRelativeFile: /User/path1/path2/hello.plist
     *               Return: /User/path1/path2/hello.pvr (If there a a key(hello.png)-value(hello.pvr) in FilenameLookup
     * dictionary. )
     *
     */
    virtual std::string fullPathFromRelativeFile(std::string_view filename, std::string_view relativeFile) const;

    /**
     *  Sets the array of search paths.
     *
     *  You can use this array to modify the search path of the resources.
     *  If you want to use "themes" or search resources in the "cache", you can do it easily by adding new entries in
     * this array.
     *
     *  @note This method could access relative path and absolute path.
     *        If the relative path was passed to the vector, FileUtils will add the default resource directory before
     * the relative path. For instance: On Android, the default resource root path is "assets/". If "/mnt/sdcard/" and
     * "resources-large" were set to the search paths vector, "resources-large" will be converted to
     * "assets/resources-large" since it was a relative path.
     *
     *  @param searchPaths The array contains search paths.
     *  @see fullPathForFilename(const char*)
     *  @since v2.1
     *  In js:var setSearchPaths(var jsval);
     *  @lua NA
     */
    virtual void setSearchPaths(const std::vector<std::string>& searchPaths);

    /**
     * Get default resource root path.
     */
    const std::string& getDefaultResourceRootPath() const;

    /**
     * Set default resource root path.
     */
    void setDefaultResourceRootPath(std::string_view path);

    /**
     * Add search path.
     *
     * @since v2.1
     */
    void addSearchPath(std::string_view path, const bool front = false);

    /**
     *  Gets the array of search paths.
     *
     *  @return The array of search paths which may contain the prefix of default resource root path.
     *  @note In best practise, getter function should return the value of setter function passes in.
     *        But since we should not break the compatibility, we keep using the old logic.
     *        Therefore, If you want to get the original search paths, please call 'getOriginalSearchPaths()' instead.
     *  @see fullPathForFilename(const char*).
     *  @lua NA
     */
    virtual const std::vector<std::string>& getSearchPaths() const;

    /**
     *  Gets the original search path array set by 'setSearchPaths' or 'addSearchPath'.
     *  @return The array of the original search paths
     */
    virtual const std::vector<std::string>& getOriginalSearchPaths() const;

    /**
     *  Gets the writable path that may not be in the format of an absolute path
     *  @return  The path that can be write/read a file in
     *  @note This may return the same value as getNativeWritableAbsolutePath(). If you require the absolute path
     *  to the underlying file system, then call getNativeWritableAbsolutePath() instead.
     */
    virtual std::string getWritablePath() const = 0;

    /**
     *  Gets the writable path in the native file-system format
     *  @return  The path that can be write/read a file in
     */
    virtual std::string getNativeWritableAbsolutePath() const = 0;

    /**
     *  Sets writable path.
     */
    virtual void setWritablePath(std::string_view writablePath);

    /**
     *  Sets whether to pop-up a message box when failed to load an image.
     */
    virtual void setPopupNotify(bool notify);

    /** Checks whether to pop up a message box when failed to load an image.
     *  @return True if pop up a message box when failed to load an image, false if not.
     */
    virtual bool isPopupNotify() const;

    /**
     *  Converts the contents of a file to a ValueMap.
     *  @param filename The filename of the file to gets content.
     *  @return ValueMap of the file contents.
     *  @note This method is used internally.
     */
    virtual ValueMap getValueMapFromFile(std::string_view filename) const;

    /** Converts the contents of a file to a ValueMap.
     *  This method is used internally.
     */
    virtual ValueMap getValueMapFromData(const char* filedata, int filesize) const;

    /**
     * write a ValueMap into a plist file
     *
     *@param dict the ValueMap want to save
     *@param fullPath The full path to the file you want to save a string
     *@return bool
     */
    virtual bool writeToFile(const ValueMap& dict, std::string_view fullPath) const;

    /**
     *  write a string into a file
     *
     * @param dataStr the string want to save
     * @param fullPath The full path to the file you want to save a string
     * @return bool True if write success
     */
    virtual bool writeStringToFile(std::string_view dataStr, std::string_view fullPath) const;

    /**
     * Write a string to a file, done async off the main cocos thread
     * Use this function if you need file access without blocking the main thread.
     *
     * This function takes a std::string by value on purpose, to leverage move sematics.
     * If you want to avoid a copy of your datastr, use std::move/std::forward if appropriate
     *
     * @param dataStr the string want to save
     * @param fullPath The full path to the file you want to save a string
     * @param callback The function called once the string has been written to a file. This
     * function will be executed on the main cocos thread. It will have on boolean argument
     * signifying if the write was successful.
     */
    virtual void writeStringToFile(std::string dataStr,
                                   std::string_view fullPath,
                                   std::function<void(bool)> callback) const;

    /**
     * write Data into a file
     *
     *@param data the data want to save
     *@param fullPath The full path to the file you want to save a string
     *@return bool
     */
    virtual bool writeDataToFile(const Data& data, std::string_view fullPath) const;

    /**
     * save data to file
     */
    static bool writeBinaryToFile(const void* data, size_t dataSize, std::string_view fullPath);

    /**
     * Write Data into a file, done async off the main cocos thread.
     *
     * Use this function if you need to write Data while not blocking the main cocos thread.
     *
     * This function takes Data by value on purpose, to leverage move sematics.
     * If you want to avoid a copy of your data, use std::move/std::forward if appropriate
     *
     *@param data The data that will be written to disk
     *@param fullPath The absolute file path that the data will be written to
     *@param callback The function that will be called when data is written to disk. This
     * function will be executed on the main cocos thread. It will have on boolean argument
     * signifying if the write was successful.
     */
    virtual void writeDataToFile(Data data, std::string_view fullPath, std::function<void(bool)> callback) const;

    /**
     * write ValueMap into a plist file
     *
     *@param dict the ValueMap want to save
     *@param fullPath The full path to the file you want to save a string
     *@return bool
     */
    virtual bool writeValueMapToFile(const ValueMap& dict, std::string_view fullPath) const;

    /**
     * Write a ValueMap into a file, done async off the main cocos thread.
     *
     * Use this function if you need to write a ValueMap while not blocking the main cocos thread.
     *
     * This function takes ValueMap by value on purpose, to leverage move sematics.
     * If you want to avoid a copy of your dict, use std::move/std::forward if appropriate
     *
     *@param dict The ValueMap that will be written to disk
     *@param fullPath The absolute file path that the data will be written to
     *@param callback The function that will be called when dict is written to disk. This
     * function will be executed on the main cocos thread. It will have on boolean argument
     * signifying if the write was successful.
     */
    virtual void writeValueMapToFile(ValueMap dict,
                                     std::string_view fullPath,
                                     std::function<void(bool)> callback) const;

    /**
     * write ValueVector into a plist file
     *
     *@param vecData the ValueVector want to save
     *@param fullPath The full path to the file you want to save a string
     *@return bool
     */
    virtual bool writeValueVectorToFile(const ValueVector& vecData, std::string_view fullPath) const;

    /**
     * Write a ValueVector into a file, done async off the main cocos thread.
     *
     * Use this function if you need to write a ValueVector while not blocking the main cocos thread.
     *
     * This function takes ValueVector by value on purpose, to leverage move sematics.
     * If you want to avoid a copy of your dict, use std::move/std::forward if appropriate
     *
     *@param vecData The ValueVector that will be written to disk
     *@param fullPath The absolute file path that the data will be written to
     *@param callback The function that will be called when vecData is written to disk. This
     * function will be executed on the main cocos thread. It will have on boolean argument
     * signifying if the write was successful.
     */
    virtual void writeValueVectorToFile(ValueVector vecData,
                                        std::string_view fullPath,
                                        std::function<void(bool)> callback) const;

    // Converts the contents of a file to a ValueVector.
    // This method is used internally.
    virtual ValueVector getValueVectorFromFile(std::string_view filename) const;

    /**
     *  Checks whether a file exists.
     *
     *  @note If a relative path was passed in, it will be inserted a default root path at the beginning.
     *  @param filename The path of the file, it could be a relative or absolute path.
     *  @return True if the file exists, false if not.
     */
    virtual bool isFileExist(std::string_view filename) const;

    /**
     * Checks if a file exists, done async off the main cocos thread.
     *
     * Use this function if you need to check if a file exists while not blocking the main cocos thread.
     *
     *  @note If a relative path was passed in, it will be inserted a default root path at the beginning.
     *  @param filename The path of the file, it could be a relative or absolute path.
     *  @param callback The function that will be called when the operation is complete. Will have one boolean
     * argument, true if the file exists, false otherwise.
     */
    virtual void isFileExist(std::string_view filename, std::function<void(bool)> callback) const;

    /**
     *  Gets filename extension is a suffix (separated from the base filename by a dot) in lower case.
     *  Examples of filename extensions are .png, .jpeg, .exe, .dmg and .txt.
     *  @param filePath The path of the file, it could be a relative or absolute path.
     *  @return suffix for filename in lower case or empty if a dot not found.
     */
    virtual std::string getFileExtension(std::string_view filePath) const;

    /**
     *  Gets filename shotName
     *  @param filePath The path of the file, it could be a relative or absolute path.
     *  @return fileName.Extension without path
     */
    static std::string getFileShortName(std::string_view filePath);

    /**
     *  Checks whether the path is an absolute path.
     *
     *  @note On Android, if the parameter passed in is relative to "assets/", this method will treat it as an absolute
     * path. Also on Blackberry, path starts with "app/native/Resources/" is treated as an absolute path.
     *
     *  @param path The path that needs to be checked.
     *  @return True if it's an absolute path, false if not.
     */
    virtual bool isAbsolutePath(std::string_view path) const;

    static bool isAbsolutePathInternal(std::string_view path);

    /**
     *  Checks whether the path is a directory.
     *
     *  @param dirPath The path of the directory, it could be a relative or an absolute path.
     *  @return True if the directory exists, false if not.
     */
    virtual bool isDirectoryExist(std::string_view dirPath) const;

    /**
     *  Checks whether the absoulate path is a directory, async off of the main cocos thread.
     *
     * @param dirPath The path of the directory, it must be an absolute path
     * @param callback that will accept a boolean, true if the file exists, false otherwise.
     * Callback will happen on the main cocos thread.
     */
    virtual void isDirectoryExist(std::string_view fullPath, std::function<void(bool)> callback) const;

    /**
     *  Creates a directory.
     *
     *  @param dirPath The path of the directory, it must be an absolute path.
     *  @return True if the directory have been created successfully, false if not.
     */
    virtual bool createDirectory(std::string_view dirPath) const;

    /**
     * Create a directory, async off the main cocos thread.
     *
     * @param dirPath the path of the directory, it must be an absolute path
     * @param callback The function that will be called when the operation is complete. Will have one boolean
     * argument, true if the directory was successfully, false otherwise.
     */
    virtual void createDirectory(std::string_view dirPath, std::function<void(bool)> callback) const;

    /**
     *  Removes a directory.
     *
     *  @param dirPath  The full path of the directory, it must be an absolute path.
     *  @return True if the directory have been removed successfully, false if not.
     */
    virtual bool removeDirectory(std::string_view dirPath) const;

    /**
     * Removes a directory, async off the main cocos thread.
     *
     * @param dirPath the path of the directory, it must be an absolute path
     * @param callback The function that will be called when the operation is complete. Will have one boolean
     * argument, true if the directory was successfully removed, false otherwise.
     */
    virtual void removeDirectory(std::string_view dirPath, std::function<void(bool)> callback) const;

    /**
     *  Removes a file.
     *
     *  @param filepath The full path of the file, it must be an absolute path.
     *  @return True if the file have been removed successfully, false if not.
     */
    virtual bool removeFile(std::string_view filepath) const;

    /**
     * Removes a file, async off the main cocos thread.
     *
     * @param filepath the path of the file to remove, it must be an absolute path
     * @param callback The function that will be called when the operation is complete. Will have one boolean
     * argument, true if the file was successfully removed, false otherwise.
     */
    virtual void removeFile(std::string_view filepath, std::function<void(bool)> callback) const;

    /**
     *  Renames a file under the given directory.
     *
     *  @param path     The parent directory path of the file, it must be an absolute path.
     *  @param oldname  The current name of the file.
     *  @param name     The new name of the file.
     *  @return True if the file have been renamed successfully, false if not.
     */
    virtual bool renameFile(std::string_view path, std::string_view oldname, std::string_view name) const;

    /**
     *  Renames a file under the given directory, async off the main cocos thread.
     *
     *  @param path     The parent directory path of the file, it must be an absolute path.
     *  @param oldname  The current name of the file.
     *  @param name     The new name of the file.
     *  @param callback The function that will be called when the operation is complete. Will have one boolean
     * argument, true if the file was successfully renamed, false otherwise.
     */
    virtual void renameFile(std::string_view path,
                            std::string_view oldname,
                            std::string_view name,
                            std::function<void(bool)> callback) const;

    /**
     *  Renames a file under the given directory.
     *
     *  @param oldfullpath  The current fullpath of the file. Includes path and name.
     *  @param newfullpath  The new fullpath of the file. Includes path and name.
     *  @return True if the file have been renamed successfully, false if not.
     */
    virtual bool renameFile(std::string_view oldfullpath, std::string_view newfullpath) const;

    /**
     *  Renames a file under the given directory, async off the main cocos thread.
     *
     *  @param oldfullpath  The current fullpath of the file. Includes path and name.
     *  @param newfullpath  The new fullpath of the file. Includes path and name.
     *  @param callback The function that will be called when the operation is complete. Will have one boolean
     * argument, true if the file was successfully renamed, false otherwise.
     */
    virtual void renameFile(std::string_view oldfullpath,
                            std::string_view newfullpath,
                            std::function<void(bool)> callback) const;

    /**
     *  Retrieve the file size.
     *
     *  @note If a relative path was passed in, it will be inserted a default root path at the beginning.
     *  @param filepath The path of the file, it could be a relative or absolute path.
     *  @return The file size.
     */
    virtual int64_t getFileSize(std::string_view filepath) const;

    /**
     *  Retrieve the file size, async off the main cocos thread.
     *
     *  @note If a relative path was passed in, it will be inserted a default root path at the beginning.
     *  @param filepath The path of the file, it could be a relative or absolute path.
     *  @param callback The function that will be called when the operation is complete. Will have one long
     * argument, the file size.
     */
    virtual void getFileSize(std::string_view filepath, std::function<void(int64_t)> callback) const;

    /**
     *  List all files in a directory.
     *
     *  @param dirPath The path of the directory, it could be a relative or an absolute path.
     *  @return File paths in a string vector
     */
    virtual std::vector<std::string> listFiles(std::string_view dirPath) const;

    /**
     * List all files in a directory async, off of the main cocos thread.
     *
     * @param dirPath The path of the directory, it could be a relative or an absolute path.
     * @param callback The callback to be called once the list operation is complete. Will be called on the main cocos
     * thread.
     * @js NA
     * @lua NA
     */
    virtual void listFilesAsync(std::string_view dirPath, std::function<void(std::vector<std::string>)> callback) const;

    /**
     *  List all files recursively in a directory.
     *
     *  @param dirPath The path of the directory, it could be a relative or an absolute path.
     *  @return File paths in a string vector
     */
    virtual void listFilesRecursively(std::string_view dirPath, std::vector<std::string>* files) const;

    /**
     *  List all files recursively in a directory, async off the main cocos thread.
     *
     *  @param dirPath The path of the directory, it could be a relative or an absolute path.
     *  @param callback The callback to be called once the list operation is complete.
     *          Will be called on the main cocos thread.
     * @js NA
     * @lua NA
     */
    virtual void listFilesRecursivelyAsync(std::string_view dirPath,
                                           std::function<void(std::vector<std::string>)> callback) const;

    /** Returns the full path cache. */
    const hlookup::string_map<std::string> getFullPathCache() const { return _fullPathCache; }

    /**
     *  Checks whether a file exists without considering search paths and resolution orders.
     *  @param filename The file (with absolute path) to look up for
     *  @return Returns true if the file found at the given absolute path, otherwise returns false
     */
    virtual bool isFileExistInternal(std::string_view filename) const = 0;

    /**
     *  Checks whether a directory exists without considering search paths and resolution orders.
     *  @param dirPath The directory (with absolute path) to look up for
     *  @return Returns true if the directory found at the given absolute path, otherwise returns false
     */
    virtual bool isDirectoryExistInternal(std::string_view dirPath) const;

    /**
     *  Open a FileStream based on the implementation provided in openFileStream or its overrides
     *  @param filePath The path to the file
     *  @param mode The mode to open the file in, being READ | WRITE | APPEND
     *  @return Returns a pointer to the file stream
     */
    virtual std::unique_ptr<FileStream> openFileStream(std::string_view filePath, FileStream::Mode mode);

protected:
    /**
     *  The default constructor.
     */
    FileUtils();

    /**
     *  Initializes the instance of FileUtils. It will set _searchPathArray.
     * values.
     *
     *  @note When you are porting Cocos2d-x to a new platform, you may need to take care of this method.
     *        You could assign a default value to _defaultResRootPath in the subclass of FileUtils(e.g.
     * FileUtilsAndroid). Then invoke the FileUtils::init().
     *  @return true if succeed, otherwise it returns false.
     *
     */
    virtual bool init();

    /**
     *  Gets full path for filename, resolution directory and search path.
     *
     *  @param filename The file name.
     *  @param searchPath The search path.
     *  @return The full path of the file. It will return an empty string if the full path of the file doesn't exist.
     */
    virtual std::string getPathForFilename(std::string_view filename,
                                           std::string_view searchPath) const;

    virtual std::string getPathForDirectory(std::string_view dir,
                                            std::string_view searchPath) const;

    /**
     *  Gets full path for the directory and the filename.
     *
     *  @note Only iOS and Mac need to override this method since they are using
     *        `[[NSBundle mainBundle] pathForResource: ofType: inDirectory:]` to make a full path.
     *        Other platforms will use the default implementation of this method.
     *  @param directory The directory contains the file we are looking for.
     *  @param filename  The name of the file.
     *  @return The full path of the file, if the file can't be found, it will return an empty string.
     */
    virtual std::string getFullPathForFilenameWithinDirectory(std::string_view directory,
                                                              std::string_view filename) const;

    /**
     * Returns the fullpath for a given dirname.
     * @since 3.17.1
     */
    virtual std::string fullPathForDirectory(std::string_view dirname) const;

    /**
     * mutex used to protect fields.
     */
    mutable std::recursive_mutex _mutex;

    /**
     * The vector contains search paths.
     * The lower index of the element in this vector, the higher priority for this search path.
     */
    std::vector<std::string> _searchPathArray;

    /**
     * The search paths which was set by 'setSearchPaths' / 'addSearchPath'.
     */
    std::vector<std::string> _originalSearchPaths;

    /**
     *  The default root path of resources.
     *  If the default root path of resources needs to be changed, do it in the `init` method of FileUtils's subclass.
     *  For instance:
     *  On Android, the default root path of resources will be assigned with "assets/" in FileUtilsAndroid::init().
     *  Similarly on Blackberry, we assign "app/native/Resources/" to this variable in FileUtilsBlackberry::init().
     */
    std::string _defaultResRootPath;

    /**
     *  The full path cache for normal files. When a file is found, it will be added into this cache.
     *  This variable is used for improving the performance of file search.
     */
    mutable hlookup::string_map<std::string> _fullPathCache;

    /**
     *  The full path cache for directories. When a diretory is found, it will be added into this cache.
     *  This variable is used for improving the performance of file search.
     */
    mutable hlookup::string_map<std::string> _fullPathCacheDir;

    /**
     * Writable path.
     */
    std::string _writablePath;

    /**
     *  The singleton pointer of FileUtils.
     */
    static FileUtils* s_sharedFileUtils;

    /**
     *  Remove null value key (for iOS)
     */
    virtual void valueMapCompact(ValueMap& valueMap) const;
    virtual void valueVectorCompact(ValueVector& valueVector) const;

    template <typename T, typename R, typename... ARGS>
    static void performOperationOffthread(T&& action, R&& callback, ARGS&&... args)
    {

        // Visual Studio 2013 does not support using std::bind to forward template parameters into
        // a lambda. To get around this, we will just copy these arguments via lambda capture
#if defined(_MSC_VER) && _MSC_VER < 1900
        auto lambda = [action, callback, args...]() {
            Director::getInstance()->getScheduler()->runOnAxmolThread(std::bind(callback, action(args...)));
        };
#else
        // As cocos2d-x uses c++11, we will use std::bind to leverage move sematics to
        // move our arguments into our lambda, to potentially avoid copying.
        auto lambda = std::bind(
            [](const T& actionIn, const R& callbackIn, const ARGS&... argsIn) {
                Director::getInstance()->getScheduler()->runOnAxmolThread(
                    std::bind(callbackIn, actionIn(argsIn...)));
            },
            std::forward<T>(action), std::forward<R>(callback), std::forward<ARGS>(args)...);

#endif

        AsyncTaskPool::getInstance()->enqueue(
            AsyncTaskPool::TaskType::TASK_IO, [](void*) {}, nullptr, std::move(lambda));
    }
};

// end of support group
/** @} */

NS_AX_END

#endif  // __AX_FILEUTILS_H__