Make fuels-accounts WASM compatible

[ra0x3]

Background

• We're adding support for indexing predicates on the indexer
• Indexing predicates isn't enough, we also need to verify that predicates came from where they're supposed to come from
• I have read over the SDK predicate docs here and understand that using the predicate ABI, and a provider, one can do some predicate derivations

Issue

• In order to verify that predicates are from the proper source @Voxelot has been kind enough to list detailed steps for doing so, that are indexer friendly
  • Those steps are here
    • Specifically this comment
      • And specifically Section 3.2 within that ☝🏼 comment

What do I ideally need?

• Ideally I need some way to derive the predicate root, at runtime, for an indexer, in a WASM-friendly way
  • The alternative is just using the non-WASM-friendly components (e.g., provider) and making FFI calls in/out of the indexer
    • Problem with this approach is that we'd effectively have to use a single provider for all indexers and all predicates
      • This might be fine?
• I do have access to:
  • The predicate ABI
  • The predicate bytecode
  • The predicate data/args
  • The relevant input/output coins
• I'm open on the best SDK way to do this however

cc @segfault-magnet @hal3e

[ra0x3]

@hal3e

• I got a response from you on this via email, but I don't see the comment now 😅
• Comment was:

There is an associated function called Predicate::calculate_address(code: &[u8], chain_id: u64) that returns the predicate root/address given the predicate bytecode and chain_id. Is this enough for the use-case ?

• Yes, calculate_address is what I'll need to use

• code being the literal predicate byte code?

• @segfault-magnet previously mentioned that I'd have to make a network call to get the chain_id

  • Is this chain_id something that might change often for a given predicate?
    • I'm wondering if I can just grab this at compile time and then just bake it into the indexer module (again, this will only work if the chain_id never changes)

• My last question was, the comment I linked to above ☝🏼 (the indexer comment with Brandon's explanation) mentions "injecting the predicate args/configurables into the predicate template"

  • This "injected predicate" (predicate with config vars injected) is what I would pass to calculate_address (I believe)
  • This sounds like something that would have to be done at runtime, since I'd have to extract the predicate data from the transaction when the transaction comes in
    • And if this has to be done at runtime, then I will need to call MyPredicateEncoder::encode_data and Predicate::load_from from the WASM module --- so these would have to be WASM-friendly
      • Is the usage of Predicate in this way WASM friendly?

Happy to hop on a call if that makes things easier, I know this is a lot :)

[ra0x3]

Spoke with @hal3e offline about this and I'll update this issue title to reflect the work he mentions needs to be done