fix(🐘): make Skia contextes per JS runtime not thread local

[wcandillon]

No description provided.

[Copilot]

Pull request overview

This PR refactors the Skia rendering context management to be per JavaScript runtime instance rather than thread-local. This change ensures that each JS runtime maintains its own graphics context, improving isolation and preventing potential issues when multiple runtimes exist.

Changes:

• Removed thread-local singleton patterns from MetalContext (Apple) and OpenGLContext (Android) in favor of per-instance contexts
• Added thread-affinity checks to OpenGL contexts to catch and prevent cross-thread usage
• Updated WindowContext ownership from unique_ptr to shared_ptr to support the new architecture

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/skia/cpp/rnskia/RNSkPlatformContext.h	Added useP3ColorSpace parameter to makeContextFromNativeSurface method
packages/skia/apple/SkiaCVPixelBufferUtils.mm	Reformatted macro definitions for consistency
packages/skia/apple/RNSkMetalCanvasProvider.mm	Removed direct MetalContext::getInstance() calls, now uses platform context
packages/skia/apple/RNSkMetalCanvasProvider.h	Changed _ctx from unique_ptr to shared_ptr
packages/skia/apple/RNSkApplePlatformContext.mm	Added instance-based metalContext() method replacing singleton pattern
packages/skia/apple/RNSkApplePlatformContext.h	Added private MetalContext member and initialization logic
packages/skia/apple/MetalContext.h	Removed singleton pattern, made constructor public
packages/skia/android/cpp/rnskia-android/RNSkOpenGLCanvasProvider.h	Changed _surfaceHolder from unique_ptr to shared_ptr
packages/skia/android/cpp/rnskia-android/RNSkOpenGLCanvasProvider.cpp	Replaced direct OpenGL context calls with platform context method
packages/skia/android/cpp/rnskia-android/RNSkAndroidVideo.h	Added _context member to hold platform context reference
packages/skia/android/cpp/rnskia-android/RNSkAndroidVideo.cpp	Updated constructor to accept and use platform context
packages/skia/android/cpp/rnskia-android/RNSkAndroidPlatformContext.h	Added getOpenGLContext() method and made class inherit from enable_shared_from_this
packages/skia/android/cpp/rnskia-android/OpenGLWindowContext.h	Added thread-affinity checking with assertThread method
packages/skia/android/cpp/rnskia-android/OpenGLWindowContext.cpp	Added thread assertions to public methods
packages/skia/android/cpp/rnskia-android/OpenGLContext.h	Removed singleton pattern, added thread-affinity checks, moved constructor implementation inline
packages/skia/android/cpp/jni/include/JniSkiaPictureView.h	Replaced direct context calls with platform context usage
externals/skia	Updated Skia submodule commit
apps/example/ios/Podfile.lock	Updated pod dependencies checksums and CocoaPods version

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[mrousavy]

Hey @wcandillon - any update on this PR?

I noticed that when I tried to create a demo app using VisionCamera V5 + Skia, memory exploded (3GB+) and the app was killed, making the VisionCamera Skia integration unusable on iOS for now.

Android works fine, since the Threading primitives don't use pools like DispatchQueue, but I still think this fix could be universal (both platforms), as static thread_local isn't really a good idea for all cases. Who knows, maybe Android has pools at some point too.

I'd love to help push this across the finish line wherever I can.