axmol/core/platform/PosixFileStream.cpp

// Copyright (c) 2018-2019 HALX99.
// Copyright (c) 2020 C4games Ltd
#include "platform/PosixFileStream.h"

#if AX_TARGET_PLATFORM == AX_PLATFORM_ANDROID
#    include "base/ZipUtils.h"
#endif

#include <sys/stat.h>
#include <assert.h>

#if defined(_WIN32)
int _ftruncate(int fd, int64_t size)
{
    auto handle = (HANDLE)_get_osfhandle(fd);
    if (handle == INVALID_HANDLE_VALUE)
        return -1;
    LARGE_INTEGER offset;
    offset.QuadPart = size;
    do
    {
        if (!::SetFilePointerEx(handle, offset, nullptr, FILE_BEGIN))
            break;
        if (!::SetEndOfFile(handle))
            break;
        return 0;
    } while (false);
    errno = GetLastError();
    return -1;
}
#endif

NS_AX_BEGIN

struct PXIoF
{
    int (*read)(PXFileHandle& handle, void*, unsigned int);
    int64_t (*seek)(PXFileHandle& handle, int64_t, int);
    int (*close)(PXFileHandle& handle);
    long long (*size)(PXFileHandle& handle);
};

static int pfs_posix_open(std::string_view path, FileStream::Mode mode, PXFileHandle& handle)
{
    switch (mode)
    {
    case FileStream::Mode::READ:
        handle._fd = posix_open_cxx(path, O_READ_FLAGS);
        break;
    case FileStream::Mode::WRITE:
        handle._fd = posix_open_cxx(path, O_WRITE_FLAGS);
        break;
    case FileStream::Mode::APPEND:
        handle._fd = posix_open_cxx(path, O_APPEND_FLAGS);
        break;
    case FileStream::Mode::OVERLAPPED:
        handle._fd = posix_open_cxx(path, O_OVERLAP_FLAGS);
        break;
    default:
        handle._fd = -1;
    }
    return handle._fd;
}

// posix standard wrappers
static int pfs_posix_read(PXFileHandle& handle, void* buf, unsigned int size)
{
    return static_cast<int>(posix_read(handle._fd, buf, size));
}
static int64_t pfs_posix_seek(PXFileHandle& handle, int64_t offst, int origin)
{
    return posix_lseek64(handle._fd, offst, origin);
}
static int pfs_posix_close(PXFileHandle& handle)
{
    int fd = handle._fd;
    if (fd != -1)
    {
        handle._fd = -1;
        return posix_close(fd);
    }
    return 0;
}
static long long pfs_posix_size(PXFileHandle& handle)
{
#if defined(_WIN32)
    return _filelengthi64(handle._fd);
#else
    struct stat st;

    if (fstat(handle._fd, &st) == 0)
        return st.st_size;

    return -1;
#endif
}

static PXIoF pfs_posix_iof = {pfs_posix_read, pfs_posix_seek, pfs_posix_close, pfs_posix_size};

#if AX_TARGET_PLATFORM == AX_PLATFORM_ANDROID
// android AssetManager wrappers
static int pfs_asset_read(PXFileHandle& handle, void* buf, unsigned int size)
{
    return AAsset_read(handle._asset, buf, size);
}
static int64_t pfs_asset_seek(PXFileHandle& handle, int64_t offst, int origin)
{
    return AAsset_seek(handle._asset, offst, origin);
}
static int pfs_asset_close(PXFileHandle& handle)
{
    if (handle._asset != nullptr)
    {
        AAsset_close(handle._asset);
        handle._asset = nullptr;
    }
    return 0;
}
static long long pfs_asset_size(PXFileHandle& handle)
{
    return AAsset_getLength64(handle._asset);
}
static PXIoF pfs_asset_iof = {pfs_asset_read, pfs_asset_seek, pfs_asset_close, pfs_asset_size};

// android obb
static int pfs_obb_read(PXFileHandle& handle, void* buf, unsigned int size)
{
    return FileUtilsAndroid::getObbFile()->zfread(&handle._zfs, buf, size);
}
static int64_t pfs_obb_seek(PXFileHandle& handle, int64_t offset, int origin)
{
    return FileUtilsAndroid::getObbFile()->zfseek(&handle._zfs, offset, origin);
}
static int pfs_obb_close(PXFileHandle& handle)
{
    FileUtilsAndroid::getObbFile()->zfclose(&handle._zfs);
    return 0;
}
static long long pfs_obb_size(PXFileHandle& handle)
{
    return FileUtilsAndroid::getObbFile()->zfsize(&handle._zfs);
}
static PXIoF pfs_obb_iof = {pfs_obb_read, pfs_obb_seek, pfs_obb_close, pfs_obb_size};
#endif

PosixFileStream::~PosixFileStream()
{
    internalClose();
}

bool PosixFileStream::open(std::string_view path, FileStream::Mode mode)
{
    bool ok = false;
#if AX_TARGET_PLATFORM != AX_PLATFORM_ANDROID
    ok = pfs_posix_open(path, mode, _handle) != -1;
#else  // Android
    if (path[0] != '/')
    {  // from package, always readonly
        std::string relativePath;
        size_t position = path.find("assets/");
        if (0 == position)
        {
            // "assets/" is at the beginning of the path and we don't want it
            relativePath = path.substr(sizeof("assets/") - 1);
        }
        else
        {
            relativePath = path;
        }

        auto obb = FileUtilsAndroid::getObbFile();
        ok       = obb != nullptr && obb->zfopen(relativePath, &_handle._zfs);
        if (ok)
        {
            this->_iof = &pfs_obb_iof;
        }
        else
        {
            AAssetManager* asMgr = FileUtilsAndroid::getAssetManager();
            AAsset* asset        = AAssetManager_open(asMgr, relativePath.c_str(), AASSET_MODE_UNKNOWN);
            ok                   = !!asset;
            if (ok)
            {
                _handle._asset = asset;
                // setup file read/seek/close at here
                this->_iof = &pfs_asset_iof;
            }
        }
    }
    else
    {  // otherwise, as a absolutely path
        ok = pfs_posix_open(path, mode, _handle) != -1;
    }
#endif

    if (ok && !_iof)
        _iof = &pfs_posix_iof;

    return ok;
}

void* PosixFileStream::getNativeHandle() const
{
#if AX_TARGET_PLATFORM != AX_PLATFORM_ANDROID
    if (_handle._fd != -1)
        return (void*)posix_fd2fh(_handle._fd);
#endif
    return nullptr;
}

int PosixFileStream::internalClose()
{
    if (_iof)
    {
        int ret = _iof->close(_handle);
        reset();
        return ret;
    }
    return 0;
}

int PosixFileStream::close()
{
    return internalClose();
}

int PosixFileStream::seek(int64_t offset, int origin)
{
    const auto result = _iof->seek(_handle, static_cast<int32_t>(offset),
                                   origin);  // this returns -1 for error, and resulting offset on success
    return result < 0 ? -1 : 0;              // return 0 for success
}

int PosixFileStream::read(void* buf, unsigned int size)
{
    return _iof->read(_handle, buf, size);
}

int PosixFileStream::write(const void* buf, unsigned int size)
{
    return static_cast<int>(posix_write(_handle._fd, buf, size));
}

int64_t PosixFileStream::tell()
{
    return _iof->seek(_handle, 0, SEEK_CUR);
}

int64_t PosixFileStream::size()
{
    return _iof->size(_handle);
}

bool PosixFileStream::isOpen() const
{
#if AX_TARGET_PLATFORM != AX_PLATFORM_ANDROID
    return _handle._fd != -1;
#else
    return _handle._fd != -1 && _handle._asset != nullptr;
#endif
}

void PosixFileStream::reset()
{
    memset(&_handle, 0, sizeof(_handle));
    _handle._fd = -1;
    _iof        = nullptr;
}

NS_AX_END