rocksdb/utilities/merge_operators/uint64add.cc
sdong fdf882ded2 Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433)
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433

Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.

Differential Revision: D19977691

fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
2020-02-20 12:09:57 -08:00

70 lines
2.1 KiB
C++

// 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).
#include <memory>
#include "logging/logging.h"
#include "rocksdb/env.h"
#include "rocksdb/merge_operator.h"
#include "rocksdb/slice.h"
#include "util/coding.h"
#include "utilities/merge_operators.h"
using namespace ROCKSDB_NAMESPACE;
namespace { // anonymous namespace
// A 'model' merge operator with uint64 addition semantics
// Implemented as an AssociativeMergeOperator for simplicity and example.
class UInt64AddOperator : public AssociativeMergeOperator {
public:
bool Merge(const Slice& /*key*/, const Slice* existing_value,
const Slice& value, std::string* new_value,
Logger* logger) const override {
uint64_t orig_value = 0;
if (existing_value){
orig_value = DecodeInteger(*existing_value, logger);
}
uint64_t operand = DecodeInteger(value, logger);
assert(new_value);
new_value->clear();
PutFixed64(new_value, orig_value + operand);
return true; // Return true always since corruption will be treated as 0
}
const char* Name() const override { return "UInt64AddOperator"; }
private:
// Takes the string and decodes it into a uint64_t
// On error, prints a message and returns 0
uint64_t DecodeInteger(const Slice& value, Logger* logger) const {
uint64_t result = 0;
if (value.size() == sizeof(uint64_t)) {
result = DecodeFixed64(value.data());
} else if (logger != nullptr) {
// If value is corrupted, treat it as 0
ROCKS_LOG_ERROR(logger, "uint64 value corruption, size: %" ROCKSDB_PRIszt
" > %" ROCKSDB_PRIszt,
value.size(), sizeof(uint64_t));
}
return result;
}
};
}
namespace ROCKSDB_NAMESPACE {
std::shared_ptr<MergeOperator> MergeOperators::CreateUInt64AddOperator() {
return std::make_shared<UInt64AddOperator>();
}
} // namespace ROCKSDB_NAMESPACE