sgx_tstd/src/sys_common/fs.rs

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License..

use crate::fs;
use crate::io::{self, Error, ErrorKind};
use crate::path::Path;

pub(crate) const NOT_FILE_ERROR: Error = io::const_io_error!(
    ErrorKind::InvalidInput,
    "the source path is neither a regular file nor a symlink to a regular file",
);

pub fn copy(from: &Path, to: &Path) -> io::Result<u64> {
    let mut reader = fs::File::open(from)?;
    let metadata = reader.metadata()?;

    if !metadata.is_file() {
        return Err(NOT_FILE_ERROR);
    }

    let mut writer = fs::File::create(to)?;
    let perm = metadata.permissions();

    let ret = io::copy(&mut reader, &mut writer)?;
    writer.set_permissions(perm)?;
    Ok(ret)
}

pub fn remove_dir_all(path: &Path) -> io::Result<()> {
    let filetype = fs::symlink_metadata(path)?.file_type();
    if filetype.is_symlink() { fs::remove_file(path) } else { remove_dir_all_recursive(path) }
}

fn remove_dir_all_recursive(path: &Path) -> io::Result<()> {
    for child in fs::read_dir(path)? {
        let child = child?;
        if child.file_type()?.is_dir() {
            remove_dir_all_recursive(&child.path())?;
        } else {
            fs::remove_file(&child.path())?;
        }
    }
    fs::remove_dir(path)
}

pub fn try_exists(path: &Path) -> io::Result<bool> {
    match fs::metadata(path) {
        Ok(_) => Ok(true),
        Err(error) if error.kind() == io::ErrorKind::NotFound => Ok(false),
        Err(error) => Err(error),
    }
}