mirror of https://gitee.com/bigwinds/arangodb
97 lines
3.2 KiB
C++
97 lines
3.2 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 Jan Steemann
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////////////////////////////////////////////////////////////////////////////////
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#include "SharedQueryState.h"
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#include "Scheduler/Scheduler.h"
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#include "Scheduler/SchedulerFeature.h"
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using namespace arangodb;
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using namespace arangodb::aql;
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void SharedQueryState::invalidate() {
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CONDITION_LOCKER(guard, _condition);
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_valid = false;
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}
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/// this has to stay for a backwards-compatible AQL HTTP API (hasMore).
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void SharedQueryState::waitForAsyncResponse() {
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CONDITION_LOCKER(guard, _condition);
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if (!_wasNotified) {
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_condition.wait();
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}
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_wasNotified = false;
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}
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/// @brief continueAfterPause is to be called on the query object to
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/// continue execution in this query part, if the query got paused
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/// because it is waiting for network responses. The idea is that a
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/// RemoteBlock that does an asynchronous cluster-internal request can
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/// register a callback with the asynchronous request and then return
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/// with the result `ExecutionState::WAITING`, which will bubble up
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/// the stack and eventually lead to a suspension of the work on the
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/// RestHandler. In the callback function one can first store the
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/// results in the RemoteBlock object and can then call this method on
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/// the query.
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/// This will lead to the following: The original request that led to
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/// the network communication will be rescheduled on the ioservice and
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/// continues its execution where it left off.
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bool SharedQueryState::execute(std::function<bool()> const& cb) {
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CONDITION_LOCKER(guard, _condition);
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if (!_valid) {
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return false;
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}
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bool res = cb();
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if (_hasHandler) {
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auto scheduler = SchedulerFeature::SCHEDULER;
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TRI_ASSERT(scheduler != nullptr);
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if (scheduler == nullptr) {
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// We are shutting down
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return false;
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}
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scheduler->post(_continueCallback);
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} else {
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_wasNotified = true;
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guard.signal();
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}
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return res;
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}
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/// @brief setter for the continue callback:
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/// We can either have a handler or a callback
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void SharedQueryState::setContinueCallback() {
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CONDITION_LOCKER(guard, _condition);
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_hasHandler = false;
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}
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/// @brief setter for the continue handler:
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/// We can either have a handler or a callback
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void SharedQueryState::setContinueHandler(std::function<void()> const& handler) {
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CONDITION_LOCKER(guard, _condition);
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_continueCallback = handler;
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_hasHandler = true;
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}
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