Optimize NativeDisplayLink to execute VSync callback on UI thread for OHOS platform. #3178

0x1306a94 · 2025-12-25T05:51:11Z

优化 OHOS 平台的 NativeDisplayLink 实现，将 VSync 的回调从独立线程切换到 UI 线程（ArkTS 线程）执行。
同时使用 native_display_soloist 替换 native_vsync

codecov-commenter · 2025-12-25T05:55:20Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.25%. Comparing base (737d973) to head (be8816b).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3178   +/-   ##
=======================================
  Coverage   77.25%   77.25%           
=======================================
  Files         413      413           
  Lines       21999    21999           
  Branches     6283     6283           
=======================================
  Hits        16996    16996           
- Misses       3797     3802    +5     
+ Partials     1206     1201    -5

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0x1306a94 · 2025-12-25T06:01:33Z

另外是不是可以替换为 NativeDisplaySoloist 这样不需要通过每帧都重新request

https://developer.huawei.com/consumer/cn/doc/harmonyos-references/capi-native-display-soloist-h

kevingpqi123 · 2025-12-25T07:28:26Z

src/platform/ohos/NativeDisplayLink.cpp

 namespace pag {

+static std::unordered_map<uint32_t, std::weak_ptr<NativeDisplayLink>> VSyncCallbacks = {};
+static napi_threadsafe_function js_threadsafe_function = nullptr;


不需要添加 VSyncCallbacks，全局只会存在一个 NativeDisplayLink 实例，多个 PAG 播放时共享同一个 VSync 回调，具体可以看下 PAGAnimator 的实现，

kevingpqi123 · 2025-12-25T07:30:07Z

src/platform/ohos/NativeDisplayLink.cpp

    playing = true;
-    OH_NativeVSync_RequestFrame(vSync, &PAGVSyncCallback, this);
+    VSyncCallbacks.insert_or_assign(id, weak_from_this());
+    OH_NativeVSync_RequestFrame(vSync, &PAGVSyncCallback, &id);


如你所说，这里 OH_NativeVSync_RequestFrame 可以切换为 NativeDisplaySoloist，避免每帧重新调用

👌晚点我再改改

0x1306a94 · 2025-12-26T11:12:13Z

@kevingpqi123 已完成修改。
由于 XComponent 每次创建都会执行 so 的 Init
而 threadsafe_function 又和 env 关联
所以我在 NativeDisplayLink::Init 的实现中每次都是重新创建

kevingpqi123 · 2025-12-26T16:07:47Z

src/platform/ohos/JPAG.cpp

                pag::JPAGDiskCache::Init(env, exports) &&
-                pag::XComponentHandler::Init(env, exports);
+                pag::XComponentHandler::Init(env, exports) &&
+                pag::NativeDisplayLink::Init(env, exports);


需要明确这里增加定义的原因，这个 Init 函数是 NAPI 模块的入口点，用于向 HarmonyOS/OpenHarmony 的 JavaScript 运行时注册 C++ 类和方法。所有需要暴露给 ArkTS/JS 层调用的 C++ 类都需要在这里初始化，如所有对外公开的 API 类，以及接收系统事件的入口。
NativeDisplayLink 就是一个系统时钟控制器，属于 C++ 内部类，不涉及上述内容

kevingpqi123 · 2025-12-26T16:16:27Z

src/platform/ohos/NativeDisplayLink.cpp

-  displayLink->callback();
-  if (displayLink->playing) {
-    OH_NativeVSync_RequestFrame(displayLink->vSync, &PAGVSyncCallback, displayLink);
+static std::weak_ptr<NativeDisplayLink> weakNativeDisplayLink;


关于 NativeDisplayLink 的实现，感觉你考虑的太复杂了，可以参考下：https://github.com/Tencent/libpag/blob/main/src/platform/ios/private/NativeDisplayLink.mm
1、关于之前提到的全局只会存在一个 NativeDisplayLink 实例，多个 PAG 播放时共享同一个 VSync 回调，这个地方是在 AnimationTicker 这个类中实现的，通过单例的方式，对于 NativeDisplayLink 就是一个正常的对象，不需要做额外的处理，正常的生命周期管理即可，AnimationTicker 这个类是在 C++ 层，不属于平台层，很方便的实现全局只有一个 VSync 回调，做到高内聚，而不是把这个功能分散到各平台层

2、相对比之前，这里的修改应该仅仅是切换主线程执行和替换接口实现，不涉及其它内容

确实。已按照建议全部进行了修改

kevingpqi123 · 2025-12-27T03:30:50Z

src/platform/ohos/JPAG.cpp

                pag::JPAGDiskCache::Init(env, exports) &&
-                pag::XComponentHandler::Init(env, exports);
+                pag::XComponentHandler::Init(env, exports) &&
+                pag::NativeDisplayLink::InitializeThreadSafeFunction(env);


这里也修改成 Init 吧

kevingpqi123 · 2025-12-27T03:32:29Z

src/platform/ohos/NativeDisplayLink.cpp


 NativeDisplayLink::~NativeDisplayLink() {
-  OH_NativeVSync_Destroy(vSync);
+  OH_DisplaySoloist_Destroy(displaySoloist);


析构的时候需要添加上 js_threadsafe_function 的释放吧，不然应用退出后会存在内存泄漏

不好意思，这一点刚处于 pending 状态，没有评论成功

应该不行。threadsafe_function 是和 env 绑定的。如果是在析构中释放的话，那需要 NativeDisplayLink 持有 env
然后在创建 NativeDisplayLink 的时候再创建 threadsafe_function

我再找找文档看看，有没有像 Android JNI 那样的机制可以通过 JavaVM 来自动获取当前的 env

这里要结合 https://github.com/Tencent/libpag/blob/main/src/rendering/PAGAnimator.cpp
的代码来看，NativeDisplayLink 在应用启动后只会创建一次，如果中间过程中发生异常被销毁，将不会再触发二次创建，后续也将不会再播放动画
std::shared_ptr PAGAnimator::MakeFrom(std::weak_ptr listener) {
if (listener.expired() || !AnimationTicker::GetInstance()->available()) {
return nullptr;
}
auto animator = std::shared_ptr(new PAGAnimator(std::move(listener)));
animator->weakThis = animator;
return animator;
}

NativeDisplayLink 是由 AnimationTicker 的单例持有的，AnimationTicker 的实例不会创建多个，其生命周期是和整个应用保持一致的，只有当应用销毁的时候，AnimationTicker 才会销毁，进而销毁 NativeDisplayLink

看了下 AnimationTicker 确实这里需要加上释放。已更新代码

… OHOS platform.

0x1306a94 requested review from Hparty, domchen and shlzxjp as code owners December 25, 2025 05:51

kevingpqi123 reviewed Dec 25, 2025

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0x1306a94 force-pushed the feature/0x1306a94_ohos_displaylink branch from a0a02d0 to e75ca47 Compare December 26, 2025 11:04

kevingpqi123 reviewed Dec 26, 2025

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0x1306a94 force-pushed the feature/0x1306a94_ohos_displaylink branch 3 times, most recently from 2251eaa to d993f82 Compare December 26, 2025 16:54

kevingpqi123 reviewed Dec 27, 2025

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0x1306a94 force-pushed the feature/0x1306a94_ohos_displaylink branch from d993f82 to 7743e7f Compare December 27, 2025 03:34

kevingpqi123 reviewed Dec 27, 2025

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Optimize NativeDisplayLink to execute VSync callback on UI thread for…

be8816b

… OHOS platform.

0x1306a94 force-pushed the feature/0x1306a94_ohos_displaylink branch from 7743e7f to be8816b Compare December 27, 2025 04:34

domchen approved these changes Dec 29, 2025

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domchen merged commit faf9831 into Tencent:main Dec 29, 2025
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Optimize NativeDisplayLink to execute VSync callback on UI thread for OHOS platform. #3178

Optimize NativeDisplayLink to execute VSync callback on UI thread for OHOS platform. #3178

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