Add locks for pinning

[dirkmc]

Currently there is no locking mechanism when modifying pins.

We should take a lock when performing any kind of pin operation, in order to prevent simultaneous pin operations from interfering with each other.

For example when adding a pin, we

• resolve the path
• get the object
• flush the pins
  • store direct pins (1)
  • store recursive pins (2)
  • store a reference to the direct/recursive nodes (1 & 2)
  • save the resulting CID to the datastore

Without locking, any of these asynchronous operations may occur concurrently and cause out-of-date or incomplete pin sets to to be stored.

The pin operations are currently managed in

• pin.js
• pin-set.js

I believe changes will only need to be made in pin.js, however the Garbage Collection PR includes some refactoring such that this structure will change somewhat, so I would suggest implementing a fix for this issue after the GC PR has landed.

We can refer to the go implementation of pinning for inspiration.

[whizzzkid]

js-ipfs is being deprecated in favor of Helia. You can follow the migration plan here #4336 and read the migration guide.

This issue has been resolved in Helia! if this does not address your concern please let us know by reopening this issue before 2023-06-05!