5917de0bae
Summary: Add CappedFixTransform, which is the same as fixed length prefix extractor, except that when slice is shorter than the fixed length, it will use the full key. Test Plan: Add a test case for db_test options_test and a new test Reviewers: yhchiang, rven, igor Reviewed By: igor Subscribers: MarkCallaghan, leveldb, dhruba, yoshinorim Differential Revision: https://reviews.facebook.net/D31887
116 lines
2.8 KiB
C++
116 lines
2.8 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2012 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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#include "rocksdb/slice_transform.h"
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#include "rocksdb/slice.h"
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#include "util/string_util.h"
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namespace rocksdb {
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namespace {
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class FixedPrefixTransform : public SliceTransform {
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private:
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size_t prefix_len_;
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std::string name_;
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public:
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explicit FixedPrefixTransform(size_t prefix_len)
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: prefix_len_(prefix_len),
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name_("rocksdb.FixedPrefix." + ToString(prefix_len_)) {}
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virtual const char* Name() const { return name_.c_str(); }
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virtual Slice Transform(const Slice& src) const {
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assert(InDomain(src));
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return Slice(src.data(), prefix_len_);
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}
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virtual bool InDomain(const Slice& src) const {
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return (src.size() >= prefix_len_);
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}
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virtual bool InRange(const Slice& dst) const {
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return (dst.size() == prefix_len_);
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}
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virtual bool SameResultWhenAppended(const Slice& prefix) const {
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return InDomain(prefix);
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}
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};
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class CappedPrefixTransform : public SliceTransform {
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private:
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size_t cap_len_;
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std::string name_;
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public:
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explicit CappedPrefixTransform(size_t cap_len)
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: cap_len_(cap_len),
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name_("rocksdb.CappedPrefix." + ToString(cap_len_)) {}
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virtual const char* Name() const { return name_.c_str(); }
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virtual Slice Transform(const Slice& src) const {
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assert(InDomain(src));
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return Slice(src.data(), std::min(cap_len_, src.size()));
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}
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virtual bool InDomain(const Slice& src) const { return true; }
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virtual bool InRange(const Slice& dst) const {
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return (dst.size() <= cap_len_);
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}
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virtual bool SameResultWhenAppended(const Slice& prefix) const {
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return prefix.size() >= cap_len_;
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}
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};
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class NoopTransform : public SliceTransform {
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public:
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explicit NoopTransform() { }
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virtual const char* Name() const {
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return "rocksdb.Noop";
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}
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virtual Slice Transform(const Slice& src) const {
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return src;
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}
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virtual bool InDomain(const Slice& src) const {
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return true;
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}
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virtual bool InRange(const Slice& dst) const {
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return true;
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}
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virtual bool SameResultWhenAppended(const Slice& prefix) const {
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return false;
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}
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};
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}
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const SliceTransform* NewFixedPrefixTransform(size_t prefix_len) {
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return new FixedPrefixTransform(prefix_len);
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}
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const SliceTransform* NewCappedPrefixTransform(size_t cap_len) {
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return new CappedPrefixTransform(cap_len);
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}
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const SliceTransform* NewNoopTransform() {
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return new NoopTransform;
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}
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} // namespace rocksdb
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