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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 std::io;
use std::ops::Range;
use std::sync::Arc;
use bytes::Bytes;
use crate::raw::*;
use crate::Buffer;
use crate::BufferIterator;
use crate::*;
/// StdIterator is the adapter of [`Iterator`] for [`BlockingReader`][crate::BlockingReader].
///
/// Users can use this adapter in cases where they need to use [`Iterator`] trait.
///
/// StdIterator also implements [`Send`] and [`Sync`].
pub struct StdBytesIterator {
iter: BufferIterator,
buf: Buffer,
}
impl StdBytesIterator {
/// NOTE: don't allow users to create StdIterator directly.
#[inline]
pub(crate) fn new(ctx: Arc<ReadContext>, range: Range<u64>) -> Self {
let iter = BufferIterator::new(ctx, range);
StdBytesIterator {
iter,
buf: Buffer::new(),
}
}
}
impl Iterator for StdBytesIterator {
type Item = io::Result<Bytes>;
fn next(&mut self) -> Option<Self::Item> {
loop {
// Consume current buffer
if let Some(bs) = Iterator::next(&mut self.buf) {
return Some(Ok(bs));
}
self.buf = match self.iter.next() {
Some(Ok(buf)) => buf,
Some(Err(err)) => return Some(Err(format_std_io_error(err))),
None => return None,
};
}
}
}