Using a skia_safe::core::surface::Surface in a multi-threaded envirnoment

[FranciscoTorrinha]

Hey guys,
So this might be a dumb question but I have ran into an issue using the skia_safe lib in a multi-threaded environment.

The current state is the following:
I have created an abstraction over skia_safe and I am now trying to use it an external context which implements Send + Sync. However rust does not allow me to do this since Surface does not implement Send + Sync, at first I assumed this could be an issue where RCHandle is a single thread ref counter but I noticed that other Structs wrapped around RCHandle are Send + Sync.

My questions here are:

• What is the reason behind Surface not being Send + Sync
• If the reason does not break the lib, is there any way I can use the Surface as Send + Sync

Thank you for your time,
Francisco

[FranciscoTorrinha]

Never mind, the issue was on my part, all I had to do is implement Send + Sync for the struct which was holding the surface
I'm sorry for the inconvenience

[pragmatrix]

Because RCHandle wrappers can be cloned at any time, making and RCHandle Send + Sync would require a mutable wrapped type to implement complete thread safety, meaning that every call must be protected by Mutexes, which Skia does not.

RCHandle wrapped types can be sent to another thread, but only at times their reference count is one. To make this possible skia-safe, implements the ConditionallySend trait.

I hope this helps to clarifies why Surface and other RCHandle types that wrap mutable Skia types do not implement Send nor Sync.