rocksdb/util/comparator.cc
Yueh-Hsuan Chiang b47d65b315 Fixed Segmentation Fault in db_stress on OSX.
Summary:
This patch provides a simplier solution to the memory leak
issue identified in patch https://reviews.facebook.net/D43677,
where a static function local variable can be used instead of
using a global static unique_ptr.

Test Plan: run db_stress on mac

Reviewers: igor, sdong, anthony, IslamAbdelRahman, maykov

Reviewed By: maykov

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D43995
2015-08-11 10:55:27 -07:00

99 lines
2.8 KiB
C++

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <algorithm>
#include <memory>
#include <stdint.h>
#include "rocksdb/comparator.h"
#include "rocksdb/slice.h"
#include "port/port.h"
#include "util/logging.h"
namespace rocksdb {
Comparator::~Comparator() { }
namespace {
class BytewiseComparatorImpl : public Comparator {
public:
BytewiseComparatorImpl() { }
virtual const char* Name() const override {
return "leveldb.BytewiseComparator";
}
virtual int Compare(const Slice& a, const Slice& b) const override {
return a.compare(b);
}
virtual void FindShortestSeparator(std::string* start,
const Slice& limit) const override {
// Find length of common prefix
size_t min_length = std::min(start->size(), limit.size());
size_t diff_index = 0;
while ((diff_index < min_length) &&
((*start)[diff_index] == limit[diff_index])) {
diff_index++;
}
if (diff_index >= min_length) {
// Do not shorten if one string is a prefix of the other
} else {
uint8_t diff_byte = static_cast<uint8_t>((*start)[diff_index]);
if (diff_byte < static_cast<uint8_t>(0xff) &&
diff_byte + 1 < static_cast<uint8_t>(limit[diff_index])) {
(*start)[diff_index]++;
start->resize(diff_index + 1);
assert(Compare(*start, limit) < 0);
}
}
}
virtual void FindShortSuccessor(std::string* key) const override {
// Find first character that can be incremented
size_t n = key->size();
for (size_t i = 0; i < n; i++) {
const uint8_t byte = (*key)[i];
if (byte != static_cast<uint8_t>(0xff)) {
(*key)[i] = byte + 1;
key->resize(i+1);
return;
}
}
// *key is a run of 0xffs. Leave it alone.
}
};
class ReverseBytewiseComparatorImpl : public BytewiseComparatorImpl {
public:
ReverseBytewiseComparatorImpl() { }
virtual const char* Name() const override {
return "rocksdb.ReverseBytewiseComparator";
}
virtual int Compare(const Slice& a, const Slice& b) const override {
return -a.compare(b);
}
};
}// namespace
const Comparator* BytewiseComparator() {
static BytewiseComparatorImpl bytewise;
return &bytewise;
}
const Comparator* ReverseBytewiseComparator() {
static ReverseBytewiseComparatorImpl rbytewise;
return &rbytewise;
}
} // namespace rocksdb