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// 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::raw::oio::BlockingWrite;
use crate::raw::*;
use crate::*;
use std::io::Write;
/// StdWriter is the adapter of [`std::io::Write`] for [`BlockingWriter`].
///
/// Users can use this adapter in cases where they need to use [`std::io::Write`] related trait.
///
/// # Notes
///
/// Files are automatically closed when they go out of scope. Errors detected on closing are ignored
/// by the implementation of Drop. Use the method `close` if these errors must be manually handled.
pub struct StdWriter {
w: Option<oio::BlockingWriter>,
buf: oio::FlexBuf,
}
impl StdWriter {
/// NOTE: don't allow users to create directly.
#[inline]
pub(crate) fn new(w: oio::BlockingWriter) -> Self {
StdWriter {
w: Some(w),
buf: oio::FlexBuf::new(256 * 1024),
}
}
/// Close the internal writer and make sure all data have been stored.
pub fn close(&mut self) -> std::io::Result<()> {
// Make sure all cache has been flushed.
self.flush()?;
let Some(w) = &mut self.w else {
return Err(std::io::Error::new(
std::io::ErrorKind::Other,
"writer has been closed",
));
};
w.close()
.map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err))?;
// Drop writer after close succeed;
self.w = None;
Ok(())
}
}
impl Write for StdWriter {
fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
let Some(w) = &mut self.w else {
return Err(std::io::Error::new(
std::io::ErrorKind::Other,
"writer has been closed",
));
};
loop {
let n = self.buf.put(buf);
if n > 0 {
return Ok(n);
}
let bs = self.buf.get().expect("frozen buffer must be valid");
let n = w
.write(Buffer::from(bs))
.map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err))?;
self.buf.advance(n);
}
}
fn flush(&mut self) -> std::io::Result<()> {
let Some(w) = &mut self.w else {
return Err(std::io::Error::new(
std::io::ErrorKind::Other,
"writer has been closed",
));
};
loop {
// Make sure buf has been frozen.
self.buf.freeze();
let Some(bs) = self.buf.get() else {
return Ok(());
};
let n = w
.write(Buffer::from(bs))
.map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err))?;
self.buf.advance(n);
}
}
}
impl Drop for StdWriter {
fn drop(&mut self) {
if let Some(mut w) = self.w.take() {
// Ignore error happens in close.
let _ = w.close();
}
}
}