add guideline file about purgeable ndk apis

Signed-off-by: Nxywang <wangxiaoyuan6@huawei.com>

 Changes to be committed:
	new file:   purgeable-memory-guidelines.md
	modified:   napi/Readme-CN.md
	new file:   napi/purgeable-memory-guidelines.md
	new file:   reference/native-apis/_purgeable_memory.md

	modified:   napi/Readme-CN.md
	new file:   napi/purgeable-memory-guidelines.md
	new file:   reference/native-apis/_purgeable_memory.md

zh-cn/application-dev/napi/Readme-CN.md

@@ -7,3 +7,4 @@
 - [NativeWindow开发指导](native-window-guidelines.md)
 - [使用MindSpore Lite引擎进行模型推理](mindspore-lite-guidelines.md)
 - [Neural Network Runtime对接AI推理框架开发指导](neural-network-runtime-guidelines.md)
+- [Purgeable memory开发指导](purgeable-memory-guidelines.md)
\ No newline at end of file

zh-cn/application-dev/napi/purgeable-memory-guidelines.md

+# 内存管理purgeable内存开发指导
+
+## 场景介绍
+
+开发者可以通过本指导了解在OpenHarmony应用中，如何使用Native purgeablememory接口操作purgeable内存。功能包括purgeable内存申请、释放。
+
+
+针对Purgeable memory，常见的开发场景如下：
+
+* 通过`Purgeablmemory`提供的`NAPI`接口申请PurgeableMemory对象，并将数据内容写入PurgeableMemory对象。
+* 使用完毕后使用
+
+## 接口说明
+
+| 接口名 | 描述 | 
+| -------- | -------- |
+| OH_PurgeableMemory \*OH_PurgeableMemory_Create(size_t size, OH_PurgeableMemory_ModifyFunc func, void \*funcPara) | 创建Purgeable memory对象，每次调用都会产生一个新的Purgeable memory对象。 | 
+| bool OH_PurgeableMemory_Destroy(OH_PurgeableMemory \*purgObj) | 将Purgeable memory对象会被析构掉。 | 
+| bool OH_PurgeableMemory_BeginRead(OH_PurgeableMemory \*purgObj) | 对purgeable对象进行读访问。 | 
+| void OH_PurgeableMemory_EndRead(OH_PurgeableMemory \*purgObj) | 读操作结束，将Purgeable对象的引用计数减1，当引用计数为0的时候， 该Purgeable memory对象可以被系统回收。 | 
+| bool OH_PurgeableMemory_BeginWrite(OH_PurgeableMemory \*purgObj) | 通过NativeWindow对象申请一块NativeWindowBuffer，用以内容生产。 | 
+|bool OH_PurgeableMemory_BeginWrite(OH_PurgeableMemory \*purgObj) | 对purgeable对象进行写访问。|
+|void OH_PurgeableMemory_EndWrite(OH_PurgeableMemory \*purgObj)|写操作结束，将Purgeable对象的引用计数减1，当引用计数为0的时候，该Purgeable memory对象可以被系统回收。|
+|void \*OH_PurgeableMemory_GetContent(OH_PurgeableMemory \*purgObj)|获取PurgeableMemory对象内存数据。|
+|size_t OH_PurgeableMemory_ContentSize(OH_PurgeableMemory \*purgObj)|获取PurgeableMemory对象内存数据大小。|
+|bool OH_PurgeableMemory_AppendModify(OH_PurgeableMemory \*purgObj, OH_PurgeableMemory_ModifyFunc func, void \*funcPara)|添加PurgeableMemory对象的修改方法。|
+
+详细的接口说明请参考[purgeable_memory](../reference/native-apis/_purgeable_memory.md)。
+
+## Purgeable应用开发步骤
+
+以下步骤描述了在**OpenHarmony**中如何使用`PurgeableMemory`提供的`NAPI`接口，申请Purgeable Memory对象，并将内容写入Purgeable对象后，对相应对象进行读写访问。
+
+1. 声明purgeable 对象创建规则
+    ```c++
+    // 声明构建函数的参数
+    struct ParaData{
+        int start;
+        int end;
+    }
+
+    // 声明一个使用ModifyFunc
+    bool FactorialFunc(void* data, size_t size, void* param){
+         bool ret = true;
+         int oriData = *(int*)(data);
+         int i = param->start;
+         while(i<param->end){
+            oriData *= i;
+         }
+         *data = oriData;
+         if(oriData < 0)
+            ret = false;
+         return ret;
+    }
+
+    // 声明修改purgeable对象扩展函数的参数
+    struct AppendParaData{
+        int newPara;
+    }
+
+    // 声明修改purgeable对象的扩展函数
+    bool AddFunc(void* data, size_t size, void* param){
+         bool ret = true;
+         int oriData = *(int*)(data);
+         oriData += param->newPara;
+         *data = oriData;
+         return ret;
+    }
+    ```
+2. 创建Purgeable对象
+    ```c++
+    // 声明一个4MB的purgeable对象大小
+    #define DATASIZE (4 * 1024 * 1024)
+
+    // 声明创建函数的参数
+    struct ParaData pdata = {1,2};
+
+    // 创建一个Purgeable对象
+    OH_PurgableMmory* pPurgmem = OH_PurgableMmory_Create(DATASIZE, FactorialFunc, &pdata);
+    ```
+
+3. 读访问Purgeable 对象
+    ```c++
+    // 读取对象
+    OH_PurgeableMemory_BeginRead(pPurgmem);
+
+    // 获取purgeable对象大小
+    size_t size = OH_PurgeableMemory_ContentSize(pPurgmem);
+
+    // 获取purgeable对象内容
+    ReqObj* pReqObj = (ReqObj*) OH_PurgeableMemory_GetContent(pPurgmem);
+
+    // 读取purgeable对象结束
+    OH_PurgeableMemory_EndRead(pPurgmem);
+    ```
+
+4. 写访问Purgeable对象
+    ```c++
+    // 修改Purgeable对象
+    OH_PurgeableMemory_BeginWrite(pPurgmem)
+
+    // 获取purgeable对象数据
+    ReqObj* pReqObj = (ReqObj*) OH_PurgeableMemory_GetContent(pPurgmem);
+
+    // 声明扩展创建函数的参数
+    struct AppendParaData apdata = {1};
+
+    // 更新purgeable 对象重建规则
+    OH_PurgeableMemory_AppendModify(pPurgmem, AddFunc, &apdata);
+
+    // 修改purgeable对象结束
+    OH_PurgeableMemory_EndWrite(pPurgmem);
+    ```
+
+5. 销毁Purgeable对象
+    ```c++
+    // 销毁对象
+    OH_PurgeableMemory_Destroy(pPurgmem);
+    ```
+
+## 相关实例
\ No newline at end of file

zh-cn/application-dev/reference/native-apis/_purgeable_memory.md

+# Purgeable Memory
+
+
+提供Purgeable Memory Native功能，主要用来开发purgeable应用。
+
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+
+**起始版本：**
+
+
+10
+
+
+## 汇总
+
+
+### 文件
+
+  | 文件名称 | 描述 | 
+| -------- | -------- |
+| [purgeable_memory.h](purgeable_memory.md) | 定义获取和使用PurgeableMemory的相关函数。
+
+
+### 结构体
+
+  | 结构体名称 | 描述 | 
+| -------- | -------- |
+| [OH_PurgeableMemory](purgeable_memory.md) | 表示Purgeable对象 |  
+
+
+### 函数
+
+| 函数名称 | 描述 | 
+| -------- | -------- |
+|OH_PurgeableMemory_Create (size_t size, OH_PurgeableMemory_ModifyFunc func, void \*funcPara) | 创建Purgeable Memory实例，每次调用都会产生一个新的Purgeable Memory实例 |
+|bool OH_PurgeableMemory_Destroy(OH_PurgeableMemory \*purgObj)| 将Purgeable memory对象会被析构掉|
+|bool OH_PurgeableMemory_BeginRead(OH_PurgeableMemory \*purgObj)|对purgeable对象进行读访问|
+|void OH_PurgeableMemory_EndRead(OH_PurgeableMemory \*purgObj)|读操作结束，将Purgeable对象的引用计数减1，当引用计数为0的时候， 该Purgeable memory对象可以被系统回收|
+|bool OH_PurgeableMemory_BeginWrite(OH_PurgeableMemory \*purgObj)|通过NativeWindow对象申请一块NativeWindowBuffer，用以内容生产|
+|bool OH_PurgeableMemory_BeginWrite(OH_PurgeableMemory \*purgObj)|对purgeable对象进行写访问|
+|void OH_PurgeableMemory_EndWrite(OH_PurgeableMemory \*purgObj)|写操作结束，将Purgeable对象的引用计数减1，当引用计数为0的时候，该Purgeable memory对象可以被系统回收|
+|void \*OH_PurgeableMemory_GetContent(OH_PurgeableMemory \*purgObj)|获取PurgeableMemory对象内存数据|
+|size_t OH_PurgeableMemory_ContentSize(OH_PurgeableMemory \*purgObj)|获取PurgeableMemory对象内存数据大小|
+|bool OH_PurgeableMemory_AppendModify(OH_PurgeableMemory \*purgObj, OH_PurgeableMemory_ModifyFunc func, void *funcPara)|添加PurgeableMemory对象的修改方法| 
+
+
+
+## 详细描述
+
+## 函数说明
+
+
+### OH_PurgeableMemory_Create()
+
+```
+OH_PurgeableMemory *OH_PurgeableMemory_Create(size_t size, OH_PurgeableMemory_ModifyFunc func, void *funcPara)
+```
+
+**描述：**
+
+创建Purgeable Memory实例，每次调用都会产生一个新的Purgeable Memory实例。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+| 名称 | 描述 | 
+| -------- | -------- |
+| size | 参数是描述purgeable对象大小的变量，类型为size_t； | 
+| func | 参数是一个指向创建函数OH_PurgeableMemory_ModifyFunc的指针，类型为sptr<OH_PurgeableMemory_ModifyFunc> |
+| funcPara | 参数是指向创建函数参数func的指针，类型可自定义 | 
+
+**返回：**
+
+返回一个指针，指向OH_PurgeableMemory的结构体实例。
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_Destroy()
+
+  
+```
+bool OH_PurgeableMemory_Destroy(OH_PurgeableMemory *purgObj)
+```
+
+**描述：**
+
+将Purgeable memory对象会被析构掉。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| purgObj | 参数是一个指向待访问的PurgeableMemory对象的指针，类型为sptr<OH_PurgeableMemory> | 
+
+**返回：**
+
+ 如果PurgeableMemory内存数据准备好则返回true；如果PurgeableMemory内存数据已被回收且重建失败则返回false。
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_BeginRead()
+
+  
+```
+bool OH_PurgeableMemory_BeginRead(OH_PurgeableMemory *purgObj)
+```
+
+**描述：**
+
+开始读取PurgeableMemory对象。检查PurgeableMemory是否被回收，若被回收则调用重建方法进行重建。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| purgObj | 参数是一个指向待访问的PurgeableMemory对象的指针，类型为sptr<OH_PurgeableMemory> | 
+
+**返回**
+
+ 如果PurgeableMemory内存数据准备好则返回ture；如果PurgeableMemory内存数据已被回收且重建失败则返回false。
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_EndRead()
+
+  
+```
+void OH_PurgeableMemory_EndRead(OH_PurgeableMemory *purgObj)
+```
+
+**描述：**
+
+结束读取PurgeableMemory对象。表示系统可回收该PurgeableMemory对象内存数据。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| purgObj | 参数是一个指向待访问的PurgeableMemory对象的指针，类型为sptr<OH_PurgeableMemory> | 
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_BeginWrite()
+
+  
+```
+bool OH_PurgeableMemory_BeginWrite(OH_PurgeableMemory *purgObj)
+```
+
+**描述：**
+
+开始修改PurgeableMemory对象。检查PurgeableMemory是否被回收，若被回收则调用重建方法进行重建。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| purgObj | 参数是一个指向待访问的PurgeableMemory对象的指针，类型为sptr<OH_PurgeableMemory> |
+
+**返回：**
+
+ 如果PurgeableMemory内存数据准备好则返回ture；如果PurgeableMemory内存数据已被回收且重建失败则返回false。
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_EndWrite()
+
+  
+```
+void OH_PurgeableMemory_EndWrite(OH_PurgeableMemory *purgObj)
+```
+
+**描述：**
+
+结束修改PurgeableMemory对象。表示系统可回收该PurgeableMemory对象内存数据。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| purgObj | 参数是一个指向待访问的PurgeableMemory对象的指针，类型为sptr<OH_PurgeableMemory> | 
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_GetContent()
+
+  
+```
+void *OH_PurgeableMemory_GetContent(OH_PurgeableMemory *purgObj)
+```
+
+**描述：**
+
+获取PurgeableMemory对象内存数据
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| purgObj | 参数是一个指向待访问的PurgeableMemory对象的指针，类型为sptr<OH_PurgeableMemory> | 
+
+**返回：**
+
+返回PurgeableMemory对象内存地址。
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_ContentSize()
+
+  
+```
+size_t OH_PurgeableMemory_ContentSize(OH_PurgeableMemory *purgObj)
+```
+
+**描述：**
+
+获取PurgeableMemory对象内存数据大小。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| purgObj | 参数是一个指向待访问的PurgeableMemory对象的指针，类型为sptr<OH_PurgeableMemory> | 
+
+**返回：**
+
+返回PurgeableMemory对象内存数据大小，类型为size_t。
+
+**起始版本：**
+
+10
+
+
+### OH_PurgeableMemory_AppendModify()
+
+  
+```
+bool OH_PurgeableMemory_AppendModify(OH_PurgeableMemory *purgObj, OH_PurgeableMemory_ModifyFunc func, void *funcPara)
+```
+
+**描述：**
+
+添加PurgeableMemory对象的修改方法,保证重建的数据是最新的数据。
+
+\@syscap SystemCapability.CommonLibrary.Memory.PurgeableMemory
+
+**参数：**
+
+  | 名称 | 描述 | 
+| -------- | -------- |
+| size | 参数是描述purgeable对象大小的变量，类型为size_t； | 
+| func | 参数是一个指向创建函数OH_PurgeableMemory_ModifyFunc的指针，类型为sptr<OH_PurgeableMemory_ModifyFunc> |
+| funcPara | 参数是指向创建函数参数func的指针，类型可自定义 | 
+
+**返回：**
+
+设置成功返回true,否则返回false。
+
+**起始版本：**
+
+10
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