WETH 智能合约就比 ERC20 多了 deposit/withdraw 进行转换

要获得 wSOL 需要了解一个指令叫 spl_token::instruction::sync_native

transfer 指令给 wSOL 的 associated_token_addr 转 SOL + sync_native 指令 够了

fn main() {
    // ...
    let token_account = spl_associated_token_account::get_associated_token_address(&payer.pubkey(), &WSOL);
    let latest_block = client.get_latest_blockhash().unwrap();
    get_wsol_balance(&client, &token_account, &payer, latest_block);

    let amount = 1_000_000;
    let instruction = solana_sdk::system_instruction::transfer(&payer.pubkey(), &token_account, amount);
    let transaction = Transaction::new_signed_with_payer(
        &[instruction],
        Some(&payer.pubkey()),
        &[&payer],
        latest_block,
    );
    client.send_and_confirm_transaction(&transaction).unwrap();
    println!("after transfer {amount}");
    get_wsol_balance(&client, &token_account, &payer, latest_block);

    let ix = spl_token::instruction::sync_native(&spl_token::ID, &token_account).unwrap();
    let transaction = Transaction::new_signed_with_payer(
        &[ix],
        Some(&payer.pubkey()),
        &[&payer],
        latest_block,
    );
    client.send_and_confirm_transaction(&transaction).unwrap();
    println!("after sync_native {amount}");
    get_wsol_balance(&client, &token_account, &payer, latest_block);
}
fn get_wsol_balance(client: &RpcClient, token_account: &Pubkey, payer: &Keypair, latest_block: Hash)  {
    let account = match client.get_account(&token_account) {
        Ok(acc) => acc,
        Err(err) => match err.kind {
            solana_client::client_error::ClientErrorKind::RpcError(
                solana_client::rpc_request::RpcError::ForUser(err),
            ) => {
                println!("{}: {err}", line!());
                let create_account_instr = spl_associated_token_account::instruction::create_associated_token_account(
                    &payer.pubkey(),
                    &token_account,
                    &WSOL,
                    &spl_token::ID,
                );
                let mut transaction =
                    Transaction::new_with_payer(&[create_account_instr], Some(&payer.pubkey()));
                transaction.sign(&[&payer], latest_block);
                client.send_and_confirm_transaction(&transaction).unwrap();
                client.get_account(&token_account).unwrap()
            }
            _ => {
                panic!("{err}");
            }
        }  
    };
    let account_state = spl_token::state::Account::unpack(&account.data).unwrap();
    let sol = account_state.amount as f64 / 1e9;
    println!("wsol = {sol}, {} lamports", account_state.amount);
}

代码的输出如下，如果转账给 wSOL 不进行 sync_native 的话，wSOL 余额是没有更新的

wsol = 0.004, 4000000 lamports
after transfer 1000000
wsol = 0.004, 4000000 lamports
after sync_native 1000000
wsol = 0.005, 5000000 lamports

我们再看看 solana 源码中怎样进行 SOl->wSOL 的

https://github.com/solana-labs/solana-program-library/blob/master/token/cli/src/command.rs#L1886

spl-token cli 源码中，创建 spl-token 并没有用 sync_native 原因是先 transfer 再 init 账户的话，init 的时候相当于执行了类似 sync_native 的效果了

所以 spl-token wrap 命令在 wSOL 账户存在的时候转入 wSOL 会报错 Error: Account already exists

只能用 transfer+sync_native 的方式

solana 源码中提到：

Burns tokens by removing them from an account. Burn does not support accounts associated with the native mint, use CloseAccount instead.

不能使用 burn 去销毁 wSOL 余额换回原生 SOL, 只能用 close 把 wSOL 账户全部退回成 SOL，不同于 WETH 合约可以部分提现 WETH 成 ETH

spl-token unwrap实际上调用的是 close account