mirror of https://gitee.com/bigwinds/arangodb
89 lines
2.1 KiB
C++
89 lines
2.1 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 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 Max Neunhoeffer
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_AQL_WALKER_WORKER_H
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#define ARANGOD_AQL_WALKER_WORKER_H 1
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#include "Basics/Common.h"
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namespace arangodb {
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namespace aql {
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/// @brief functionality to walk an execution plan recursively
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template <class T>
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class WalkerWorker {
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public:
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WalkerWorker() = default;
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virtual ~WalkerWorker() = default;
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virtual bool before(T*) {
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return false; // true to abort the whole walking process
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}
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virtual void after(T*) {}
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virtual bool enterSubquery(T*, T*) { // super, sub
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return true;
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}
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virtual void leaveSubquery(T*, // super,
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T* // sub
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) {}
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#ifdef ARANGODB_ENABLE_FAILURE_TESTS
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bool done(T* en) {
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// make sure a node is only processed once
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if (_done.emplace(en).second) {
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return false;
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}
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// should never happen
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TRI_ASSERT(false);
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return true;
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}
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void reset() { _done.clear(); }
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#else
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// this is a no-op in non-failure mode
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bool done(T*) { return false; }
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// this is a no-op in non-failure mode
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void reset() {}
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#endif
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private:
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#ifdef ARANGODB_ENABLE_FAILURE_TESTS
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arangodb::HashSet<T*> _done;
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#endif
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};
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} // namespace aql
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} // namespace arangodb
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#endif
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