rocksdb/db/history_trimming_iterator.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <string>
#include <vector>
#include "db/dbformat.h"
#include "rocksdb/iterator.h"
#include "rocksdb/slice.h"
#include "table/internal_iterator.h"
namespace ROCKSDB_NAMESPACE {
class HistoryTrimmingIterator : public InternalIterator {
public:
explicit HistoryTrimmingIterator(InternalIterator* input,
const Comparator* cmp, const std::string& ts)
: input_(input), filter_ts_(ts), cmp_(cmp) {
assert(cmp_->timestamp_size() > 0 && !ts.empty());
}
bool filter() const {
if (!input_->Valid()) {
return true;
}
Slice current_ts = ExtractTimestampFromKey(key(), cmp_->timestamp_size());
return cmp_->CompareTimestamp(current_ts, Slice(filter_ts_)) <= 0;
}
bool Valid() const override { return input_->Valid(); }
void SeekToFirst() override {
input_->SeekToFirst();
while (!filter()) {
input_->Next();
}
}
void SeekToLast() override {
input_->SeekToLast();
while (!filter()) {
input_->Prev();
}
}
void Seek(const Slice& target) override {
input_->Seek(target);
while (!filter()) {
input_->Next();
}
}
void SeekForPrev(const Slice& target) override {
input_->SeekForPrev(target);
while (!filter()) {
input_->Prev();
}
}
void Next() override {
do {
input_->Next();
} while (!filter());
}
void Prev() override {
do {
input_->Prev();
} while (!filter());
}
Slice key() const override { return input_->key(); }
Slice value() const override { return input_->value(); }
Status status() const override { return input_->status(); }
bool IsKeyPinned() const override { return input_->IsKeyPinned(); }
bool IsValuePinned() const override { return input_->IsValuePinned(); }
private:
InternalIterator* input_;
const std::string filter_ts_;
const Comparator* const cmp_;
};
} // namespace ROCKSDB_NAMESPACE