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1 /*
2  * Copyright (c) 2023 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef OHOS_UTILS_MEMORY_LIBPURGEABLEMEM_CPP_INCLUDE_PURGEABLE_MEM_BASE_H
17 #define OHOS_UTILS_MEMORY_LIBPURGEABLEMEM_CPP_INCLUDE_PURGEABLE_MEM_BASE_H
18 
19 #include <memory> /* unique_ptr */
20 #include <shared_mutex> /* shared_mutex */
21 #include <string>
22 
23 #include "purgeable_mem_builder.h"
24 #include "purgeable_resource_manager.h"
25 #include "ux_page_table.h"
26 #include "ffrt.h"
27 
28 namespace OHOS {
29 namespace PurgeableMem {
30 class PurgeableMemBase {
31 public:
32     /*
33      * BeginRead: begin read the PurgeableMem obj.
34      * Return:  return true if the obj's content is present.
35      *          If content is purged(no present), system will recover its data,
36      *          return false if content is purged and recover failed.
37      *          While return true if content recover success.
38      * OS cannot reclaim the memory of the obj's content when this
39      * function return true, until EndRead() is called.
40      */
41     bool BeginRead();
42 
43     /*
44      * EndRead: end read the PurgeableMem obj.
45      * OS may reclaim the memory of its content
46      * at a later time when this function returns.
47      */
48     void EndRead();
49 
50     /*
51      * BeginRead: begin read the PurgeableMem obj.
52      * Return:  return true if the obj's content is present.
53      *          If content is purged(no present), system will recover its data,
54      *          return false if content is purged and recover failed.
55      *          While return true if content recover success.
56      * OS cannot reclaim the memory of the obj's content when this
57      * function return true, until EndRead() is called.
58      */
59 
60     bool BeginWrite();
61 
62     /*
63      * EndWrite: end write the PurgeableMem obj.
64      * OS may reclaim the memory of its content
65      * at a later time when this function returns.
66      */
67     void EndWrite();
68 
69     /*
70      * ModifyContentByBuilder: append a PurgeableMemBuilder obj to the PurgeableMem obj.
71      * Input:   @modifier: unique_ptr of PurgeableMemBuilder, it will modify content of this obj.
72      * Return:  modify result, true is success, while false is fail.
73      * This function should be protected by BeginWrite()/EndWrite().
74      */
75     bool ModifyContentByBuilder(std::unique_ptr<PurgeableMemBuilder> modifier);
76 
77     /*
78      * GetContent: get content ptr of the PurgeableMem obj.
79      * Return:  return the content ptr, which is start address of the obj's content.
80      * This function should be protected by BeginRead()/EndRead()
81      * or BeginWrite()/EndWrite().
82      */
83     void *GetContent();
84 
85     /*
86      * GetContentSize: get content size of the PurgeableMem obj.
87      * Return:  return content size of the obj's content.
88      */
89     size_t GetContentSize();
90 
91     /*
92      * ResizeData: resize size of the PurgeableMem obj.
93      */
94     virtual void ResizeData(size_t newSize);
95     void SetRebuildSuccessCallback(std::function<void()> &callback);
96     bool IsDataValid();
97     void SetDataValid(bool target);
98     bool BeginReadWithDataLock();
99     void EndReadWithDataLock();
100 
101     PurgeableMemBase();
102     virtual ~PurgeableMemBase();
103     PurgeableMemBase(const PurgeableMemBase&) = delete;
104     PurgeableMemBase& operator = (PurgeableMemBase&) = delete;
105     PurgeableMemBase(PurgeableMemBase&&) noexcept = delete;
106     PurgeableMemBase& operator = (PurgeableMemBase&&) noexcept = delete;
107 
108 protected:
109     void *dataPtr_ = nullptr;
110     ffrt::mutex dataLock_;
111     bool isDataValid_ {true};
112     size_t dataSizeInput_ = 0;
113     std::unique_ptr<PurgeableMemBuilder> builder_ = nullptr;
114     std::shared_mutex rwlock_;
115     unsigned int buildDataCount_ = 0;
116     bool BuildContent_();
117     bool IfNeedRebuild_();
118     virtual bool Pin();
119     virtual bool Unpin();
120     virtual bool IsPurged();
121     virtual int GetPinStatus() const;
122     virtual void AfterRebuildSucc();
123     virtual std::string ToString() const;
124     friend class PurgeableResourceManager;
125 };
126 } /* namespace PurgeableMem */
127 } /* namespace OHOS */
128 #endif /* OHOS_UTILS_MEMORY_LIBPURGEABLEMEM_CPP_INCLUDE_PURGEABLE_MEM_BASE_H */
129