fileLength

fn fileLength(userdata: ?*anyopaque, file: File) File.LengthError!u64

File

Code

fn fileLength(userdata: ?*anyopaque, file: File) File.LengthError!u64 {
    const t: *Threaded = @ptrCast(@alignCast(userdata));

    if (native_os == .linux) {
        const linux = std.os.linux;

        const syscall: Syscall = try .start();
        while (true) {
            var statx = std.mem.zeroes(linux.Statx);
            switch (linux.errno(linux.statx(file.handle, "", linux.AT.EMPTY_PATH, .{ .SIZE = true }, &statx))) {
                .SUCCESS => {
                    syscall.finish();
                    if (!statx.mask.SIZE) return error.Unexpected;
                    return statx.size;
                },
                .INTR => {
                    try syscall.checkCancel();
                    continue;
                },
                else => |e| {
                    syscall.finish();
                    switch (e) {
                        .ACCES => |err| return errnoBug(err),
                        .BADF => |err| return errnoBug(err), // File descriptor used after closed.
                        .FAULT => |err| return errnoBug(err),
                        .INVAL => |err| return errnoBug(err),
                        .LOOP => |err| return errnoBug(err),
                        .NAMETOOLONG => |err| return errnoBug(err),
                        .NOENT => |err| return errnoBug(err),
                        .NOMEM => return error.SystemResources,
                        .NOTDIR => |err| return errnoBug(err),
                        else => |err| return posix.unexpectedErrno(err),
                    }
                },
            }
        }
    } else if (is_windows) {
        var io_status_block: windows.IO_STATUS_BLOCK = undefined;
        var info: windows.FILE.STANDARD_INFORMATION = undefined;
        const syscall: Syscall = try .start();
        while (true) switch (windows.ntdll.NtQueryInformationFile(
            file.handle,
            &io_status_block,
            &info,
            @sizeOf(windows.FILE.STANDARD_INFORMATION),
            .Standard,
        )) {
            .SUCCESS => break syscall.finish(),
            .INVALID_PARAMETER => |err| return syscall.ntstatusBug(err),
            .ACCESS_DENIED => return syscall.fail(error.AccessDenied),
            .CANCELLED => {
                try syscall.checkCancel();
                continue;
            },
            else => |s| return syscall.unexpectedNtstatus(s),
        };
        return @as(u64, @bitCast(info.EndOfFile));
    }

    const stat = try fileStat(t, file);
    return stat.size;
}