msb_krun_utils 0.1.0

Shared utilities for msb_krun microVMs
Documentation 
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// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

use std::os::raw::c_int;

/// Wrapper to interpret syscall exit codes and provide a rustacean `io::Result`
pub struct SyscallReturnCode(pub c_int);
impl SyscallReturnCode {
    /// Returns the last OS error if value is -1 or Ok(value) otherwise.
    pub fn into_result(self) -> std::io::Result<c_int> {
        if self.0 == -1 {
            Err(std::io::Error::last_os_error())
        } else {
            Ok(self.0)
        }
    }

    /// Returns the last OS error if value is -1 or Ok(()) otherwise.
    pub fn into_empty_result(self) -> std::io::Result<()> {
        self.into_result().map(|_| ())
    }
}