36a5f8ed7f
- Replace raw slice comparison with a call to user comparator.
Added test for custom comparators.
- Fix end of namespace comments.
- Fixed bug in picking inputs for a level-0 compaction.
When finding overlapping files, the covered range may expand
as files are added to the input set. We now correctly expand
the range when this happens instead of continuing to use the
old range. For example, suppose L0 contains files with the
following ranges:
F1: a .. d
F2: c .. g
F3: f .. j
and the initial compaction target is F3. We used to search
for range f..j which yielded {F2,F3}. However we now expand
the range as soon as another file is added. In this case,
when F2 is added, we expand the range to c..j and restart the
search. That picks up file F1 as well.
This change fixes a bug related to deleted keys showing up
incorrectly after a compaction as described in Issue 44.
(Sync with upstream @25072954)
67 lines
1.6 KiB
C++
67 lines
1.6 KiB
C++
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#ifndef STORAGE_LEVELDB_DB_SNAPSHOT_H_
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#define STORAGE_LEVELDB_DB_SNAPSHOT_H_
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#include "leveldb/db.h"
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namespace leveldb {
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class SnapshotList;
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// Snapshots are kept in a doubly-linked list in the DB.
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// Each SnapshotImpl corresponds to a particular sequence number.
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class SnapshotImpl : public Snapshot {
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public:
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SequenceNumber number_; // const after creation
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private:
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friend class SnapshotList;
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// SnapshotImpl is kept in a doubly-linked circular list
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SnapshotImpl* prev_;
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SnapshotImpl* next_;
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SnapshotList* list_; // just for sanity checks
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};
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class SnapshotList {
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public:
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SnapshotList() {
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list_.prev_ = &list_;
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list_.next_ = &list_;
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}
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bool empty() const { return list_.next_ == &list_; }
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SnapshotImpl* oldest() const { assert(!empty()); return list_.next_; }
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SnapshotImpl* newest() const { assert(!empty()); return list_.prev_; }
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const SnapshotImpl* New(SequenceNumber seq) {
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SnapshotImpl* s = new SnapshotImpl;
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s->number_ = seq;
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s->list_ = this;
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s->next_ = &list_;
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s->prev_ = list_.prev_;
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s->prev_->next_ = s;
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s->next_->prev_ = s;
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return s;
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}
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void Delete(const SnapshotImpl* s) {
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assert(s->list_ == this);
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s->prev_->next_ = s->next_;
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s->next_->prev_ = s->prev_;
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delete s;
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}
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private:
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// Dummy head of doubly-linked list of snapshots
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SnapshotImpl list_;
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};
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_DB_SNAPSHOT_H_
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