Memory management

[sgenoud]

How is the generation handling reference counting?

Is the memory of an object automatically freed when the javascript pointer to is is also freed? Or should I manage my memory manually?

Thanks!

P.S. Thanks for your work! It is great not to have to put my hands too deep in the C code 😉.

[donalffons]

Hey!

JavaScript doesn't currently provide a simple way to hook into the garbage collection process. Therefore, there is no automatic freeing of memory, which you allocated via JS using const myObject = new openCascade.AnyClass(). I.e. you have to call myObject.delete() when you don't need this object any longer.

This memory is not immediately available again to be used by the browser and/or operating system:
When instantiating the WebAssembly module, a chunk of memory is created and assigned to it via a JavaScript ArrayBuffer. This ArrayBuffer has an initial size from which it can grow - however it can never shrink (I believe, this is a limitation of the WebAssembly spec). I.e. when you're delete()ing memory as mentioned above, that memory will be free and available to be used by the WebAssembly instance, OpenCascade.js in this case. It will not be given back to the browser / operating system until that ArrayBuffer is destroyed.

Maybe it would be possible to implement automatic memory management using JavaScript WeakMaps in the future, but for the moment memory management is all manual.