1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
/**
* Copyright (C) 2021-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/db/pipeline/window_function/window_function.h"
namespace mongo {
class WindowFunctionPush final : public WindowFunctionState {
public:
using ValueListConstIterator = std::list<Value>::const_iterator;
static inline const Value kDefault = Value{std::vector<Value>()};
static std::unique_ptr<WindowFunctionState> create(ExpressionContext* const expCtx) {
return std::make_unique<WindowFunctionPush>(expCtx);
}
explicit WindowFunctionPush(ExpressionContext* const expCtx) : WindowFunctionState(expCtx) {
_memUsageBytes = sizeof(*this);
}
void add(Value value) override {
_memUsageBytes += value.getApproximateSize();
_values.push_back(std::move(value));
}
/**
* This should only remove the first/lowest element in the window.
*/
void remove(Value value) override {
tassert(5423801, "Can't remove from an empty WindowFunctionPush", _values.size() != 0);
auto valToRemove = _values.front();
tassert(
5414202,
"Attempted to remove an element other than the first element from WindowFunctionPush",
_expCtx->getValueComparator().evaluate(valToRemove == value));
_values.pop_front();
_memUsageBytes -= value.getApproximateSize();
}
void reset() override {
_values.clear();
_memUsageBytes = sizeof(*this);
}
Value getValue() const override {
std::vector<Value> output;
if (_values.empty())
return kDefault;
return Value{std::vector<Value>(_values.begin(), _values.end())};
}
private:
std::deque<Value> _values;
};
} // namespace mongo
|
