Problem: disorganised wasm binding code in bindings/wasm/src/lib.rs (fix #225)

[stevenatcrypto]

Close #225

Summary

. Separate wasm binding code to cosmos_sdk.rs, ethereum.rs and nft.rs (as frist step of refactor).

. Add struct CosmosClient and CosmosClientConfig as below.

pub struct CosmosClient {
    config: CosmosClientConfig,
}

impl CosmosClient {
    #[wasm_bindgen(constructor)]
    pub fn new(config: CosmosClientConfig) -> Self {
        Self { config }
    }

    pub fn query_account_balance(&self, address: String, denom: String, api_version: u8) -> Promise { ... }
    pub fn query_account_details(&self, address: String) -> Promise { ... }
    pub fn broadcast_tx(&self, raw_signed_tx: Vec<u8>) -> Promise { ... }
}

pub struct CosmosClientConfig {
    api_url: String,
    tendermint_rpc_url: String,
}

With js_sys::Promise and feature_to_promise, we could convert Rust async instance functions (&self and in a struct) to return JS promise.
In JS example, we could send a transaction as below.

// Create a transaction.
const tx = new wasm.CosmosTx();

// Add a staking delegate message.
tx.add_msg(wasm.CosmosMsg.build_staking_delegate_msg( ... ));

// Add a bank send message.
tx.add_msg(wasm.CosmosMsg.build_bank_send_msg( ... ));

// Sign the transaction and move out all pending messages.
const txData = tx.sign_into( ... );

const config = new wasm.CosmosClientConfig(
  CHAINMAIN_API_URL,
  TENDERMINT_RPC_URL,
);
const client = new wasm.CosmosClient(config);

// Broadcast signed transaction data.
await client.broadcast_tx(txData);

. I add a new issue #244 to delete C-Style functions in wasm binding and update integration-test. I will fix it in another PR. Thanks.

[tomtau]

is this necessary?
if e.g. this could be

#[wasm_bindgen]
pub async query_account_balance(...) -> Result<JsValue, JsValue> {
  query_account_balance(self.config.api_url.clone(), address, denom, api_version).await
}

and wasm-bindgen will automatically convert to promises?

[stevenatcrypto]

I am sorry that I didn't mention the issue I met.
A below error occurred if directly use async on instance functions. It seems that self cannot live long in JS environment.

error[E0597]: `me` does not live long enough
  --> bindings/wasm/src/cosmos_sdk.rs:19:1
   |
19 | #[wasm_bindgen]
   | ^^^^^^^^^^^^^^-
   | |             |
   | |             `me` dropped here while still borrowed
   | borrowed value does not live long enough
   | argument requires that `me` is borrowed for `'static`

I found this wasm-bindgen issue and a solution comment. It seems that returning Promise explicitly is better than wrapping self with Rc<RefCell<Self>>. What do you think? Thanks.

[tomtau]

I see, that is probably better.
I think @damoncro faced similar issues before with the grpc-web functions