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41 lines
1.5 KiB
41 lines
1.5 KiB
// Copyright 2018-2019 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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use super::ErrorImpl;
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use crate::backend::traits::BackendIter;
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pub struct IterImpl<'i, C> {
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// LMDB semantics dictate that a cursor must be valid for the entire lifetime
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// of an iterator. In other words, cursors must not be dropped while an
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// iterator built from it is alive. Unfortunately, the LMDB crate API does
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// not express this through the type system, so we must enforce it somehow.
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#[allow(dead_code)]
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cursor: C,
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iter: lmdb::Iter<'i>,
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}
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impl<'i, C> IterImpl<'i, C> {
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pub(crate) fn new(
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mut cursor: C,
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to_iter: impl FnOnce(&mut C) -> lmdb::Iter<'i>,
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) -> IterImpl<'i, C> {
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let iter = to_iter(&mut cursor);
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IterImpl { cursor, iter }
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}
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}
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impl<'i, C> BackendIter<'i> for IterImpl<'i, C> {
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type Error = ErrorImpl;
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#[allow(clippy::type_complexity)]
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fn next(&mut self) -> Option<Result<(&'i [u8], &'i [u8]), Self::Error>> {
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self.iter.next().map(|e| e.map_err(ErrorImpl::LmdbError))
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}
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}
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