1// Copyright (C) 2021 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#ifndef QRECYCLEPOOL_P_H
5#define QRECYCLEPOOL_P_H
6
7//
8// W A R N I N G
9// -------------
10//
11// This file is not part of the Qt API. It exists purely as an
12// implementation detail. This header file may change from version to
13// version without notice, or even be removed.
14//
15// We mean it.
16//
17
18#include <QtCore/private/qglobal_p.h>
19
20QT_BEGIN_NAMESPACE
21
22#define QRECYCLEPOOLCOOKIE 0x33218ADF
23
24template<typename T, int Step>
25class QRecyclePoolPrivate
26{
27public:
28 QRecyclePoolPrivate()
29 : recyclePoolHold(true), outstandingItems(0), cookie(QRECYCLEPOOLCOOKIE),
30 currentPage(nullptr), nextAllocated(nullptr)
31 {
32 }
33
34 bool recyclePoolHold;
35 int outstandingItems;
36 quint32 cookie;
37
38 struct PoolType : public T {
39 union {
40 QRecyclePoolPrivate<T, Step> *pool;
41 PoolType *nextAllocated;
42 };
43 };
44
45 struct Page {
46 Page *nextPage;
47 unsigned int free;
48 union {
49 char array[Step * sizeof(PoolType)];
50 qint64 q_for_alignment_1;
51 double q_for_alignment_2;
52 };
53 };
54
55 Page *currentPage;
56 PoolType *nextAllocated;
57
58 inline T *allocate();
59 static inline void dispose(T *);
60 inline void releaseIfPossible();
61};
62
63template<typename T, int Step = 1024>
64class QRecyclePool
65{
66public:
67 inline QRecyclePool();
68 inline ~QRecyclePool();
69
70 inline T *New() = delete;
71 template<typename T1>
72 inline T *New(const T1 &);
73 template<typename T1>
74 inline T *New(T1 &);
75
76 static inline void Delete(T *);
77
78private:
79 QRecyclePoolPrivate<T, Step> *d;
80};
81
82template<typename T, int Step>
83QRecyclePool<T, Step>::QRecyclePool()
84: d(new QRecyclePoolPrivate<T, Step>())
85{
86}
87
88template<typename T, int Step>
89QRecyclePool<T, Step>::~QRecyclePool()
90{
91 d->recyclePoolHold = false;
92 d->releaseIfPossible();
93}
94
95template<typename T, int Step>
96template<typename T1>
97T *QRecyclePool<T, Step>::New(const T1 &a)
98{
99 T *rv = d->allocate();
100 return new (rv) T(a);
101}
102
103template<typename T, int Step>
104template<typename T1>
105T *QRecyclePool<T, Step>::New(T1 &a)
106{
107 T *rv = d->allocate();
108 return new (rv) T(a);
109}
110
111template<typename T, int Step>
112void QRecyclePool<T, Step>::Delete(T *t)
113{
114 t->~T();
115 QRecyclePoolPrivate<T, Step>::dispose(t);
116}
117
118template<typename T, int Step>
119void QRecyclePoolPrivate<T, Step>::releaseIfPossible()
120{
121 if (recyclePoolHold || outstandingItems)
122 return;
123
124 Page *p = currentPage;
125 while (p) {
126 Page *n = p->nextPage;
127 free(p);
128 p = n;
129 }
130
131 delete this;
132}
133
134template<typename T, int Step>
135T *QRecyclePoolPrivate<T, Step>::allocate()
136{
137 PoolType *rv = nullptr;
138 if (nextAllocated) {
139 rv = nextAllocated;
140 nextAllocated = rv->nextAllocated;
141 } else if (currentPage && currentPage->free) {
142 rv = (PoolType *)(currentPage->array + (Step - currentPage->free) * sizeof(PoolType));
143 currentPage->free--;
144 } else {
145 Page *p = (Page *)malloc(size: sizeof(Page));
146 p->nextPage = currentPage;
147 p->free = Step;
148 currentPage = p;
149
150 rv = (PoolType *)currentPage->array;
151 currentPage->free--;
152 }
153
154 rv->pool = this;
155 ++outstandingItems;
156 return rv;
157}
158
159template<typename T, int Step>
160void QRecyclePoolPrivate<T, Step>::dispose(T *t)
161{
162 PoolType *pt = static_cast<PoolType *>(t);
163 Q_ASSERT(pt->pool && pt->pool->cookie == QRECYCLEPOOLCOOKIE);
164
165 QRecyclePoolPrivate<T, Step> *This = pt->pool;
166 pt->nextAllocated = This->nextAllocated;
167 This->nextAllocated = pt;
168 --This->outstandingItems;
169 This->releaseIfPossible();
170}
171
172QT_END_NAMESPACE
173
174#endif // QRECYCLEPOOL_P_H
175

source code of qtdeclarative/src/qml/qml/ftw/qrecyclepool_p.h