mirror of https://gitee.com/bigwinds/arangodb
115 lines
3.4 KiB
C++
115 lines
3.4 KiB
C++
////////////////////////////////////////////////////////////////////////////////
|
|
/// DISCLAIMER
|
|
///
|
|
/// Copyright 2019 ArangoDB GmbH, Cologne, Germany
|
|
///
|
|
/// Licensed under the Apache License, Version 2.0 (the "License");
|
|
/// you may not use this file except in compliance with the License.
|
|
/// You may obtain a copy of the License at
|
|
///
|
|
/// http://www.apache.org/licenses/LICENSE-2.0
|
|
///
|
|
/// Unless required by applicable law or agreed to in writing, software
|
|
/// distributed under the License is distributed on an "AS IS" BASIS,
|
|
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
/// See the License for the specific language governing permissions and
|
|
/// limitations under the License.
|
|
///
|
|
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
|
|
///
|
|
/// @author Michael Hackstein
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#ifndef ARANGOD_AQL_AQL_CALL_H
|
|
#define ARANGOD_AQL_AQL_CALL_H 1
|
|
|
|
#include "Aql/ExecutionBlock.h"
|
|
|
|
#include <cstddef>
|
|
#include <variant>
|
|
|
|
namespace arangodb {
|
|
namespace aql {
|
|
struct AqlCall {
|
|
class Infinity {};
|
|
using Limit = std::variant<size_t, Infinity>;
|
|
|
|
// TODO Remove me, this will not be necessary later
|
|
static AqlCall SimulateSkipSome(std::size_t toSkip) {
|
|
AqlCall call;
|
|
call.offset = toSkip;
|
|
call.softLimit = 0;
|
|
call.hardLimit = AqlCall::Infinity{};
|
|
call.fullCount = false;
|
|
return call;
|
|
}
|
|
|
|
// TODO Remove me, this will not be necessary later
|
|
static AqlCall SimulateGetSome(std::size_t atMost) {
|
|
AqlCall call;
|
|
call.offset = 0;
|
|
call.softLimit = atMost;
|
|
call.hardLimit = AqlCall::Infinity{};
|
|
call.fullCount = false;
|
|
return call;
|
|
}
|
|
|
|
// TODO Remove me, this will not be necessary later
|
|
static bool IsSkipSomeCall(AqlCall const& call) {
|
|
return !call.hasHardLimit() && call.getLimit() == 0 && call.getOffset() > 0;
|
|
}
|
|
|
|
// TODO Remove me, this will not be necessary later
|
|
static bool IsGetSomeCall(AqlCall const& call) {
|
|
return !call.hasHardLimit() && call.getLimit() > 0 && call.getOffset() == 0;
|
|
}
|
|
|
|
std::size_t offset{0};
|
|
// TODO: The defaultBatchSize function could move into this file instead
|
|
Limit softLimit{Infinity{}};
|
|
Limit hardLimit{Infinity{}};
|
|
bool fullCount{false};
|
|
|
|
std::size_t getOffset() const { return offset; }
|
|
|
|
std::size_t getLimit() const {
|
|
// By default we use batchsize
|
|
std::size_t limit = ExecutionBlock::DefaultBatchSize();
|
|
// We are not allowed to go above softLimit
|
|
if (std::holds_alternative<std::size_t>(softLimit)) {
|
|
limit = (std::min)(std::get<std::size_t>(softLimit), limit);
|
|
}
|
|
// We are not allowed to go above hardLimit
|
|
if (std::holds_alternative<std::size_t>(hardLimit)) {
|
|
limit = (std::min)(std::get<std::size_t>(hardLimit), limit);
|
|
}
|
|
return limit;
|
|
}
|
|
|
|
void didSkip(std::size_t n) {
|
|
TRI_ASSERT(n <= offset);
|
|
offset -= n;
|
|
}
|
|
|
|
void didProduce(std::size_t n) {
|
|
if (std::holds_alternative<std::size_t>(softLimit)) {
|
|
TRI_ASSERT(n <= std::get<std::size_t>(softLimit));
|
|
softLimit = std::get<std::size_t>(softLimit) - n;
|
|
}
|
|
if (std::holds_alternative<std::size_t>(hardLimit)) {
|
|
TRI_ASSERT(n <= std::get<std::size_t>(hardLimit));
|
|
hardLimit = std::get<std::size_t>(hardLimit) - n;
|
|
}
|
|
}
|
|
|
|
bool hasHardLimit() const {
|
|
return !std::holds_alternative<AqlCall::Infinity>(hardLimit);
|
|
}
|
|
|
|
bool needsFullCount() const { return fullCount; }
|
|
};
|
|
|
|
} // namespace aql
|
|
} // namespace arangodb
|
|
|
|
#endif |