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本文档主要针对NativeWindow、NativeBuffer和NativeImage开发过程中的常见问题进行说明,帮助开发者及时避免或定位对应问题,提高应用稳定性。
OHNativeWindow与NativeWindowBuffer在系统多个模块与应用之间传递,通过增加与减少引用计数的NDK接口实现伪智能指针,由各模块维护自己的引用计数,超过90%的问题都是由于增减引用计数接口未匹配导致的。
增加NativeWindow引用计数的接口:
- int32_t OH_NativeWindow_NativeObjectReference(void *obj)
-
- int32_t OH_NativeWindow_CreateNativeWindowFromSurfaceId(uint64_t surfaceId, OHNativeWindow **window)
-
- OHNativeWindow* OH_NativeImage_AcquireNativeWindow(OH_NativeImage* image)
-
- int32_t OH_NativeWindow_ReadFromParcel(OHIPCParcel *parcel, OHNativeWindow **window)
减少NativeWindow引用计数的接口:
- int32_t OH_NativeWindow_NativeObjectUnreference(void *obj)
-
- void OH_NativeWindow_DestroyNativeWindow(OHNativeWindow* window)
-
- void OH_NativeImage_Destroy(OH_NativeImage** image)
增加NativeWindowBuffer引用计数的接口:
- int32_t OH_NativeWindow_NativeObjectReference(void *obj)
-
- int32_t OH_NativeWindow_GetLastFlushedBufferV2(OHNativeWindow *window, OHNativeWindowBuffer **buffer,int *fenceFd, float matrix[16])
-
- OHNativeWindowBuffer* OH_NativeWindow_CreateNativeWindowBufferFromNativeBuffer(OH_NativeBuffer* nativeBuffer)
-
- int32_t OH_NativeImage_AcquireNativeWindowBuffer(OH_NativeImage* image,OHNativeWindowBuffer** nativeWindowBuffer, int* fenceFd)
减少NativeWindowBuffer引用计数的接口:
- int32_t OH_NativeWindow_NativeObjectUnreference(void *obj)
-
- void OH_NativeWindow_DestroyNativeWindowBuffer(OHNativeWindowBuffer* buffer)
-
- int32_t OH_NativeImage_ReleaseNativeWindowBuffer(OH_NativeImage* image,OHNativeWindowBuffer* nativeWindowBuffer, int fenceFd) // 仅接口返回成功时减少引用计数
典型崩溃日志如下:
- **典型崩溃日志1**
- 00 /system/lib64/chipset-sdk-sp/libsurface.z.so(OH_NativeWindow_DestroyNativeWindow())
-
- **典型崩溃日志2**
- 00 /system/lib64/chipset-sdk-sp/libsurface.z.so(……)
- 01 /system/lib64/chipset-sdk-sp/libsurface.z.so(……)
- 02 /system/lib64/chipset-sdk-sp/libsurface.z.so(OH_NativeWindow_NativeWindowHandleOpt)
-
- **典型崩溃日志3**
- 00 /system/lib64/chipset-sdk-sp/libsurface.z.so(OH_NativeWindow_NativeObjectUnreference())
可能原因如下:
1.错误地减少了一次NativeWindow引用计数,导致NativeWindow计数减为0释放后,其他地方调用或者再次减计数时崩溃。
2.从XComponent组件获取的NativeWindow,抛向子线程使用,XComponent组件销毁时将NativeWindow引用计数减一,若减为0析构后,子线程仍在使用会导致崩溃。
典型错误代码1
- OH_NativeImage *image_ = OH_NativeImage_Create(textureId, GL_TEXTURE_2D);
- OHNativeWindow *nativewindow_ = OH_NativeImage_AcquireNativeWindow(image_);
-
- // 错误:OH_NativeImage_Destroy中会减少OHNativeWindow引用计数,无需再调用OH_NativeWindow_DestroyNativeWindow
- OH_NativeImage_Destroy(image_);
- OH_NativeWindow_DestroyNativeWindow(nativewindow_);
具体解析
OH_NativeImage_Destroy中会减少OHNativeWindow引用计数,无需再调用OH_NativeWindow_DestroyNativeWindow。
修改:删除OH_NativeWindow_DestroyNativeWindow(nativewindow_),并在OH_NativeImage_Destroy后及时将image_和nativewindow_置空,防止后续使用野指针。
- OH_NativeImage *image_ = OH_NativeImage_Create(textureId, GL_TEXTURE_2D);
- OHNativeWindow *nativewindow_ = OH_NativeImage_AcquireNativeWindow(image_);
-
- // 释放NativeImage时将image_和nativewindow_置空,防止后续使用野指针
- OH_NativeImage_Destroy(image_);
- image_ = nullptr;
- nativewindow_ = nullptr;
典型错误代码2
- void OnSurfaceCreatedCB(OH_NativeXComponent* component, void* window)
- {
- uint64_t width = 0;
- uint64_t height = 0;
- int32_t ret = OH_NativeXComponent_GetXComponentSize(component, window, &width, &height);
- OHNativeWindow* nativewindow_ = static_cast<OHNativeWindow*>(window);
-
- // 未对NativeWindow增加引用计数直接抛向子线程使用
- NativeRender::GetInstance()->SetNativeWindow(nativewindow_, width, height);
- }
-
- void OnSurfaceDestroyedCB(OH_NativeXComponent* component, void* window)
- {
- if ((component == nullptr) || (window == nullptr)) {
- LOGE("OnSurfaceDestroyedCB: component or window is null");
- return;
- }
-
- // 错误:通知子线程停止,但未做等待操作,OnSurfaceDestroyedCB结束后NativeWindow可能被释放,子线程正在使用可能崩溃
- NativeRender::GetInstance()->Release();
- OHNativeWindow* nativewindow_ = static_cast<OHNativeWindow*>(window);
- // 错误:未对nativewindow_引用计数加一的情况下调用DestroyNativeWindow会使nativewindow_提前释放,导致崩溃
- OH_NativeWindow_DestroyNativeWindow(nativewindow_);
- }
具体解析
从XComponent组件获取NativeWindow后,传递给渲染子线程使用,当页面退出,XComponent组件销毁时,会将NativeWindow引用计数减一,应用未对NativeWindow引用加一的情况下NativeWindow会被释放,此时子线程仍在使用可能导致并发崩溃。
修改方案一:在将NativeWindow传递给子线程前,将其引用计数加一,此时XComponent组件销毁时,因应用持有NativeWindow引用计数,NativeWindow不会销毁,当子线程使用完成后将其引用计数减一。
- void OnSurfaceCreatedCB(OH_NativeXComponent* component, void* window)
- {
- uint64_t width = 0;
- uint64_t height = 0;
- int32_t ret = OH_NativeXComponent_GetXComponentSize(component, window, &width, &height);
- OHNativeWindow* nativewindow_ = static_cast<OHNativeWindow*>(window);
-
- // 抛任务前将nativeWindow引用计数加一
- OH_NativeWindow_NativeObjectReference(nativewindow_);
- NativeRender::GetInstance()->SetNativeWindow(nativewindow_, width, height);
- }
-
- void OnSurfaceDestroyedCB(OH_NativeXComponent* component, void* window)
- {
- if ((component == nullptr) || (window == nullptr)) {
- LOGE("OnSurfaceDestroyedCB: component or window is null");
- return;
- }
-
- // 通知子线程停止,因为前面有对引用计数加一,OnSurfaceDestroyedCB结束时不会释放
- // 当子线程使用完毕后执行OH_NativeWindow_NativeObjectUnreference(nativewindow_)对引用计数减一
- NativeRender::GetInstance()->Release();
- }
修改方案二:在XComponent组件销毁的OnSurfaceDestroyedCB回调通知中,通知子线程停止并等待,直到子线程结束,避免NativeWindow销毁后子线程还在使用。
- void OnSurfaceCreatedCB(OH_NativeXComponent* component, void* window)
- {
- uint64_t width = 0;
- uint64_t height = 0;
- int32_t ret = OH_NativeXComponent_GetXComponentSize(component, window, &width, &height);
- OHNativeWindow* nativewindow_ = static_cast<OHNativeWindow*>(window);
-
- NativeRender::GetInstance()->SetNativeWindow(nativewindow_, width, height);
- }
-
- void OnSurfaceDestroyedCB(OH_NativeXComponent* component, void* window)
- {
- if ((component == nullptr) || (window == nullptr)) {
- LOGE("OnSurfaceDestroyedCB: component or window is null");
- return;
- }
-
- NativeRender::GetInstance()->Release();
- // 通知子线程停止后等待子线程任务结束再结束OnSurfaceDestroyedCB
- renderThread.join();
- }
典型崩溃日志如下:
- **典型崩溃日志1**
- 00 /system/lib64/chipset-sdk-sp/libsurface.z.so(OH_NativeWindow_GetBufferHandleFromNative())
-
- **典型崩溃日志2**
- 00 /system/lib64/chipset-sdk-sp/libsurface.z.so(OH_NativeWindow_NativeObjectUnreference())
-
- **典型崩溃日志3**
- 00 /system/lib64/chipset-sdk-sp/libsurface.z.so(OH_NativeWindow_NativeObjectReference())
可能原因如下:
从XComponent组件获取的NativeWindow,抛向子线程使用,XComponent组件销毁时将NativeWindow计数减一,NativeWindow销毁时对内部的NativeWindowBuffer引用计数减一,此时子线程刚RequestBuffer拿到buffer正在使用导致崩溃。
同上述NativeWindow生命周期问题的典型错误代码及解决方案。
典型卡死日志如下:
- /system/lib64/chipset-sdk-sp/libsurface.z.so(RequestBufferLocked())
可能原因如下:
应用申请了buffer,但未归还,导致后续无可用buffer,再次申请buffer时卡住。
典型错误代码
- auto ret = OH_NativeWindow_NativeWindowRequestBuffer(nativewindow_, &buffer, &fence);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
-
- // 错误:异常分支未归还buffer,NativeWindow内buffer数量固定,可能导致后续无buffer可用卡死
- if (error) {
- return;
- }
-
- OH_NativeWindow_NativeWindowFlushBuffer(nativewindow_, buffer, fence, region);
具体解析
NativeWindow中的NativeWindowBuffer数量固定,当只申请buffer未归还,会导致NativeWindow内buffer耗尽,再次申请buffer时卡死。
修改:确保申请的buffer一定会归还到NativeWindow中,成功绘制的可通过OH_NativeWindow_NativeWindowFlushBuffer归还,未绘制的可通过OH_NativeWindow_NativeWindowAbortBuffer归还。
- auto ret = OH_NativeWindow_NativeWindowRequestBuffer(nativewindow_, &buffer, &fence);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
-
- if (error) {
- // 异常分支归还buffer
- OH_NativeWindow_NativeWindowAbortBuffer(nativewindow_, buffer);
- return;
- }
-
- OH_NativeWindow_NativeWindowFlushBuffer(nativewindow_, buffer, fence, region);
额外执行了增加引用计数接口,未配套执行减少引用计数接口导致泄漏。
典型错误代码1
- auto ret = OH_NativeWindow_NativeWindowRequestBuffer(nativewindow_, &buffer, &fence);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
- ret = OH_NativeWindow_NativeObjectReference(buffer);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
-
- // 错误:对buffer增加了引用计数,绘制流程走到异常分支,异常分支未相应减少引用计数,导致泄漏
- if (error) {
- OH_NativeWindow_NativeWindowAbortBuffer(nativewindow_, buffer);
- return;
- }
-
- OH_NativeWindow_NativeWindowFlushBuffer(nativewindow_, buffer, fence, region);
- OH_NativeWindow_NativeObjectReference(buffer);
具体解析
申请buffer后增加引用计数延长其生命周期,未配套减少引用计数,导致该buffer无法被释放。
修改:确保增加引用计数后有配套调用减少引用计数接口。
- auto ret = OH_NativeWindow_NativeWindowRequestBuffer(nativewindow_, &buffer, &fence);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
- ret = OH_NativeWindow_NativeObjectReference(buffer);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
-
- if (error) {
- // 异常分支配套减少引用计数
- OH_NativeWindow_NativeWindowAbortBuffer(nativewindow_, buffer);
- OH_NativeWindow_NativeObjectUnreference(buffer);
- return;
- }
-
- OH_NativeWindow_NativeWindowFlushBuffer(nativewindow_, buffer, fence, region);
- OH_NativeWindow_NativeObjectUnreference(buffer);
典型错误代码2
- auto ret = OH_NativeImage_AcquireNativeWindowBuffer(nativeimage, &buffer, &fence);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
- ret = OH_NativeWindow_NativeObjectReference(buffer);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
-
- // 错误:未对Release失败场景处理,AcquireNativeWindowBuffer成功会对buffer引用计数加一,ReleaseNativeWindowBuffer失败不会减一
- OH_NativeImage_ReleaseNativeWindowBuffer(nativeimage, buffer, fence);
- OH_NativeWindow_NativeObjectUnreference(buffer);
具体解析
OH_NativeImage_AcquireNativeWindowBuffer接口获取的buffer会增加引用计数,OH_NativeImage_ReleaseNativeWindowBuffer接口只在成功时减少引用计数,未对返回值做处理会导致内存泄漏。
修改:OH_NativeImage_ReleaseNativeWindowBuffer接口返回不为NATIVE_ERROR_OK时,额外调用OH_NativeWindow_NativeObjectUnreference减少一次引用计数。
- auto ret = OH_NativeImage_AcquireNativeWindowBuffer(nativeimage, &buffer, &fence);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
- ret = OH_NativeWindow_NativeObjectReference(buffer);
- if (ret != NATIVE_ERROR_OK) {
- return;
- }
-
- // 对OH_NativeImage_ReleaseNativeWindowBuffer失败做异常处理
- ret = OH_NativeImage_ReleaseNativeWindowBuffer(nativeimage, buffer, fence);
- if (ret != NATIVE_ERROR_OK) {
- OH_NativeWindow_NativeObjectUnreference(buffer);
- }
- OH_NativeWindow_NativeObjectUnreference(buffer);