mirror of https://gitee.com/bigwinds/arangodb
128 lines
3.4 KiB
C++
128 lines
3.4 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// @brief recursive execution plan walker
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///
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/// @file
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///
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/// DISCLAIMER
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///
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/// Copyright 2010-2014 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 triAGENS GmbH, Cologne, Germany
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///
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/// @author Max Neunhoeffer
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/// @author Copyright 2014, triagens GmbH, Cologne, Germany
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGODB_AQL_WALKER_WORKER_H
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#define ARANGODB_AQL_WALKER_WORKER_H 1
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#include "Basics/Common.h"
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namespace triagens {
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namespace aql {
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////////////////////////////////////////////////////////////////////////////////
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/// @brief functionality to walk an execution plan recursively
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////////////////////////////////////////////////////////////////////////////////
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template<class T> class WalkerWorker {
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// -----------------------------------------------------------------------------
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// --SECTION-- constructors / destructors
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// -----------------------------------------------------------------------------
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public:
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WalkerWorker () {
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}
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virtual ~WalkerWorker () {
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- public functions
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// -----------------------------------------------------------------------------
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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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}
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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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}
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#ifdef TRI_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.find(en) == _done.end()) {
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_done.emplace(en);
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return false;
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}
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TRI_ASSERT(false);
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return true;
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}
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void reset () {
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_done.clear();
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}
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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*) {
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return false;
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}
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// this is a no-op in non-failure mode
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void reset () {
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}
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#endif
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// -----------------------------------------------------------------------------
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// --SECTION-- private variables
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// -----------------------------------------------------------------------------
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private:
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#ifdef TRI_ENABLE_FAILURE_TESTS
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std::unordered_set<T*> _done;
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#endif
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};
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}
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}
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#endif
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// Local Variables:
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// mode: outline-minor
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// outline-regexp: "^\\(/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|// --SECTION--\\|/// @\\}\\)"
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// End:
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