mirror of https://gitee.com/bigwinds/arangodb
117 lines
3.7 KiB
C++
117 lines
3.7 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2017 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Jan Steemann
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/// @author Daniel H. Larkin
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////////////////////////////////////////////////////////////////////////////////
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#include "RocksDBComparator.h"
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#include "Basics/VelocyPackHelper.h"
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#include "RocksDBEngine/RocksDBKey.h"
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#include "RocksDBEngine/RocksDBPrefixExtractor.h"
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#include "RocksDBEngine/RocksDBTypes.h"
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#include <velocypack/Iterator.h>
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#include <velocypack/velocypack-aliases.h>
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using namespace arangodb;
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namespace {
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int compareIndexedValues(arangodb::velocypack::Slice const& lhs,
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arangodb::velocypack::Slice const& rhs) {
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TRI_ASSERT(lhs.isArray());
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TRI_ASSERT(rhs.isArray());
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arangodb::velocypack::ArrayIterator lhsIter(lhs);
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arangodb::velocypack::ArrayIterator rhsIter(rhs);
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size_t const lLength = lhsIter.size();
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size_t const rLength = rhsIter.size();
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while (lhsIter.valid() || rhsIter.valid()) {
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size_t i = lhsIter.index();
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int res = arangodb::basics::VelocyPackHelper::compare(
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(i < lLength ? *lhsIter : VPackSlice::noneSlice()),
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(i < rLength ? *rhsIter : VPackSlice::noneSlice()), true);
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if (res != 0) {
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return res;
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}
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++lhsIter;
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++rhsIter;
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}
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return static_cast<int>(lLength - rLength);
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}
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} // namespace
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int RocksDBVPackComparator::compareIndexValues(rocksdb::Slice const& lhs,
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rocksdb::Slice const& rhs) const {
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constexpr size_t objectIDLength = RocksDBKey::objectIdSize();
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int r = memcmp(lhs.data(), rhs.data(), objectIDLength);
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if (r != 0) {
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// different object ID
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return r;
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}
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if (ADB_UNLIKELY(lhs.size() == objectIDLength || rhs.size() == objectIDLength)) {
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if (lhs.size() == rhs.size()) {
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return 0;
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}
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return ((lhs.size() < rhs.size()) ? -1 : 1);
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}
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TRI_ASSERT(lhs.size() > sizeof(uint64_t));
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TRI_ASSERT(rhs.size() > sizeof(uint64_t));
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VPackSlice const lSlice = VPackSlice(reinterpret_cast<uint8_t const*>(lhs.data()) + sizeof(uint64_t));
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VPackSlice const rSlice = VPackSlice(reinterpret_cast<uint8_t const*>(rhs.data()) + sizeof(uint64_t));
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r = ::compareIndexedValues(lSlice, rSlice);
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if (r != 0) {
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// comparison of index values produced an unambiguous result
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return r;
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}
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// index values were identical. now compare the leftovers (which is the
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// LocalDocumentId for non-unique indexes)
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constexpr size_t offset = sizeof(uint64_t);
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size_t const lOffset = offset + static_cast<size_t>(lSlice.byteSize());
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size_t const rOffset = offset + static_cast<size_t>(rSlice.byteSize());
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size_t const lSize = lhs.size() - lOffset;
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size_t const rSize = rhs.size() - rOffset;
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size_t minSize = std::min(lSize, rSize);
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if (minSize > 0) {
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char const* lBase = lhs.data() + lOffset;
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char const* rBase = rhs.data() + rOffset;
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r = memcmp(lBase, rBase, minSize);
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if (r != 0) {
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return r;
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}
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}
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return static_cast<int>(lSize - rSize);
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}
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