SDL/src/storage/generic/SDL_genericstorage.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#include "SDL_internal.h"

#include "../SDL_sysstorage.h"


static char *GENERIC_INTERNAL_CreateFullPath(const char *base, const char *relative)
{
    const char *rel = relative;

#ifdef SDL_PLATFORM_ANDROID
    if (rel) {
        // Removes any leading slash
        if (rel[0] == '/' || rel[0] == '\\') {
            rel += 1;
        }
    }
#endif

    char *result = NULL;
    SDL_asprintf(&result, "%s%s", base ? base : "", rel ? rel : "");
    return result;
}

static bool GENERIC_CloseStorage(void *userdata)
{
    SDL_free(userdata);
    return true;
}

typedef struct GenericEnumerateData
{
    size_t base_len;
    SDL_EnumerateDirectoryCallback real_callback;
    void *real_userdata;
} GenericEnumerateData;

static SDL_EnumerationResult SDLCALL GENERIC_EnumerateDirectory(void *userdata, const char *dirname, const char *fname)
{
    // SDL_EnumerateDirectory will return the full path, so for Storage we
    // can take the base directory and add its length to the dirname string,
    // effectively trimming the root without having to strdup anything.
    const GenericEnumerateData *wrap_data = (GenericEnumerateData *)userdata;

    dirname += wrap_data->base_len;  // skip the base, just return the part inside of the Storage.

    #ifdef SDL_PLATFORM_WINDOWS
    char *dirnamecpy = NULL;
    const size_t slen = SDL_strlen(dirname);
    if (slen && (dirname[slen - 1] == '\\')) {
        dirnamecpy = SDL_strdup(dirname);
        if (!dirnamecpy) {
            return SDL_ENUM_FAILURE;
        }
        dirnamecpy[slen - 1] = '/';  // storage layer always uses '/' path separators.
        dirname = dirnamecpy;
    }
    const SDL_EnumerationResult retval = wrap_data->real_callback(wrap_data->real_userdata, dirname, fname);
    SDL_free(dirnamecpy);
    return retval;
    #else
    return wrap_data->real_callback(wrap_data->real_userdata, dirname, fname);
    #endif
}

static bool GENERIC_EnumerateStorageDirectory(void *userdata, const char *path, SDL_EnumerateDirectoryCallback callback, void *callback_userdata)
{
    bool result = false;
    GenericEnumerateData wrap_data;

    char *fullpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, path);
    if (fullpath) {
        wrap_data.base_len = userdata ? SDL_strlen((char *)userdata) : 0;
        wrap_data.real_callback = callback;
        wrap_data.real_userdata = callback_userdata;

        result = SDL_EnumerateDirectory(fullpath, GENERIC_EnumerateDirectory, &wrap_data);

        SDL_free(fullpath);
    }
    return result;
}

static bool GENERIC_GetStoragePathInfo(void *userdata, const char *path, SDL_PathInfo *info)
{
    bool result = false;

    char *fullpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, path);
    if (fullpath) {
        result = SDL_GetPathInfo(fullpath, info);

        SDL_free(fullpath);
    }
    return result;
}

static bool GENERIC_ReadStorageFile(void *userdata, const char *path, void *destination, Uint64 length)
{
    bool result = false;

    if (length > SDL_SIZE_MAX) {
        return SDL_SetError("Read size exceeds SDL_SIZE_MAX");
    }

    char *fullpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, path);
    if (fullpath) {
        SDL_IOStream *stream = SDL_IOFromFile(fullpath, "rb");
        if (stream) {
            // FIXME: Should SDL_ReadIO use u64 now...?
            if (SDL_ReadIO(stream, destination, (size_t)length) == length) {
                result = true;
            } else {
                SDL_SetError("File length did not exactly match the destination length");
            }
            SDL_CloseIO(stream);
        }
        SDL_free(fullpath);
    }
    return result;
}

static bool GENERIC_WriteStorageFile(void *userdata, const char *path, const void *source, Uint64 length)
{
    // TODO: Recursively create subdirectories with SDL_CreateDirectory
    bool result = false;

    if (length > SDL_SIZE_MAX) {
        return SDL_SetError("Write size exceeds SDL_SIZE_MAX");
    }

    char *fullpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, path);
    if (fullpath) {
        SDL_IOStream *stream = SDL_IOFromFile(fullpath, "wb");

        if (stream) {
            // FIXME: Should SDL_WriteIO use u64 now...?
            if (SDL_WriteIO(stream, source, (size_t)length) == length) {
                result = true;
            } else {
                SDL_SetError("Resulting file length did not exactly match the source length");
            }
            SDL_CloseIO(stream);
        }
        SDL_free(fullpath);
    }
    return result;
}

static bool GENERIC_CreateStorageDirectory(void *userdata, const char *path)
{
    // TODO: Recursively create subdirectories with SDL_CreateDirectory
    bool result = false;

    char *fullpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, path);
    if (fullpath) {
        result = SDL_CreateDirectory(fullpath);

        SDL_free(fullpath);
    }
    return result;
}

static bool GENERIC_RemoveStoragePath(void *userdata, const char *path)
{
    bool result = false;

    char *fullpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, path);
    if (fullpath) {
        result = SDL_RemovePath(fullpath);

        SDL_free(fullpath);
    }
    return result;
}

static bool GENERIC_RenameStoragePath(void *userdata, const char *oldpath, const char *newpath)
{
    bool result = false;

    char *fulloldpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, oldpath);
    char *fullnewpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, newpath);
    if (fulloldpath && fullnewpath) {
        result = SDL_RenamePath(fulloldpath, fullnewpath);
    }
    SDL_free(fulloldpath);
    SDL_free(fullnewpath);

    return result;
}

static bool GENERIC_CopyStorageFile(void *userdata, const char *oldpath, const char *newpath)
{
    bool result = false;

    char *fulloldpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, oldpath);
    char *fullnewpath = GENERIC_INTERNAL_CreateFullPath((char *)userdata, newpath);
    if (fulloldpath && fullnewpath) {
        result = SDL_CopyFile(fulloldpath, fullnewpath);
    }
    SDL_free(fulloldpath);
    SDL_free(fullnewpath);

    return result;
}

static Uint64 GENERIC_GetStorageSpaceRemaining(void *userdata)
{
    // TODO: There's totally a way to query a folder root's quota...
    return SDL_MAX_UINT64;
}

static const SDL_StorageInterface GENERIC_title_iface = {
    sizeof(SDL_StorageInterface),
    GENERIC_CloseStorage,
    NULL,   // ready
    GENERIC_EnumerateStorageDirectory,
    GENERIC_GetStoragePathInfo,
    GENERIC_ReadStorageFile,
    NULL,   // write_file
    NULL,   // mkdir
    NULL,   // remove
    NULL,   // rename
    NULL,   // copy
    NULL    // space_remaining
};

static SDL_Storage *GENERIC_Title_Create(const char *override, SDL_PropertiesID props)
{
    SDL_Storage *result = NULL;
    char *basepath = NULL;

    if (override != NULL) {
        const size_t slen = SDL_strlen(override);
        if (slen > 0) {
            // make sure override has a path separator at the end. If you're not on Windows and used '\\', that's on you.
            const bool need_sep = ((override[slen - 1] != '/') && (override[slen - 1] != '\\'));
            if (SDL_asprintf(&basepath, "%s%s", override, need_sep ? "/" : "") == -1) {
                return NULL;
            }
        } else {
            // override == "" -> empty base (not "/")
            basepath = SDL_strdup("");
        }
    } else {
        const char *base = SDL_GetBasePath();
        // On Android, SDL_GetBasePath() can be NULL: use empty base.
#ifdef SDL_PLATFORM_ANDROID
        basepath = base ? SDL_strdup(base) : SDL_strdup("");
#else
        basepath = base ? SDL_strdup(base) : NULL;
#endif
    }

    if (basepath != NULL) {
        result = SDL_OpenStorage(&GENERIC_title_iface, basepath);
        if (result == NULL) {
            SDL_free(basepath);  // otherwise CloseStorage will free it.
        }
    }

    return result;
}

TitleStorageBootStrap GENERIC_titlebootstrap = {
    "generic",
    "SDL generic title storage driver",
    GENERIC_Title_Create
};

static const SDL_StorageInterface GENERIC_user_iface = {
    sizeof(SDL_StorageInterface),
    GENERIC_CloseStorage,
    NULL,   // ready
    GENERIC_EnumerateStorageDirectory,
    GENERIC_GetStoragePathInfo,
    GENERIC_ReadStorageFile,
    GENERIC_WriteStorageFile,
    GENERIC_CreateStorageDirectory,
    GENERIC_RemoveStoragePath,
    GENERIC_RenameStoragePath,
    GENERIC_CopyStorageFile,
    GENERIC_GetStorageSpaceRemaining
};

static SDL_Storage *GENERIC_User_Create(const char *org, const char *app, SDL_PropertiesID props)
{
    SDL_Storage *result;
    char *prefpath = SDL_GetPrefPath(org, app);
    if (prefpath == NULL) {
        return NULL;
    }

    result = SDL_OpenStorage(&GENERIC_user_iface, prefpath);
    if (result == NULL) {
        SDL_free(prefpath);  // otherwise CloseStorage will free it.
    }
    return result;
}

UserStorageBootStrap GENERIC_userbootstrap = {
    "generic",
    "SDL generic user storage driver",
    GENERIC_User_Create
};

static const SDL_StorageInterface GENERIC_file_iface = {
    sizeof(SDL_StorageInterface),
    GENERIC_CloseStorage,
    NULL,   // ready
    GENERIC_EnumerateStorageDirectory,
    GENERIC_GetStoragePathInfo,
    GENERIC_ReadStorageFile,
    GENERIC_WriteStorageFile,
    GENERIC_CreateStorageDirectory,
    GENERIC_RemoveStoragePath,
    GENERIC_RenameStoragePath,
    GENERIC_CopyStorageFile,
    GENERIC_GetStorageSpaceRemaining
};

SDL_Storage *GENERIC_OpenFileStorage(const char *path)
{
    SDL_Storage *result;
    char *basepath = NULL;
    char *prepend = NULL;
    bool is_absolute = false;

    if (!path || !*path) {
#ifdef SDL_PLATFORM_WINDOWS
        path = "C:/";
#else
        path = "/";
#endif
    }

#ifdef SDL_PLATFORM_WINDOWS
    const char ch = (char) SDL_toupper(path[0]);
    is_absolute = (ch == '/') ||   // some sort of absolute Unix-style path.
                  (ch == '\\') ||  // some sort of absolute Windows-style path.
                  (((ch >= 'A') && (ch <= 'Z')) && (path[1] == ':') && ((path[2] == '\\') || (path[2] == '/')));  // an absolute path with a drive letter.
#else
    is_absolute = (path[0] == '/');   // some sort of absolute Unix-style path.
#endif
    if (!is_absolute) {
        prepend = SDL_GetCurrentDirectory();
        if (!prepend) {
            return NULL;
        }
    }

    const size_t len = SDL_strlen(path);
    const char *appended_separator = "";
#ifdef SDL_PLATFORM_WINDOWS
    if ((path[len-1] != '/') && (path[len-1] != '\\')) {
        appended_separator = "/";
    }
#else
    if (path[len-1] != '/') {
        appended_separator = "/";
    }
#endif
    const int rc = SDL_asprintf(&basepath, "%s%s%s", prepend ? prepend : "", path, appended_separator);
    SDL_free(prepend);
    if (rc < 0) {
        return NULL;
    }

    result = SDL_OpenStorage(&GENERIC_file_iface, basepath);
    if (result == NULL) {
        SDL_free(basepath);
    }
    return result;
}