Add easy functions for token transfers

[metaproph3t]

When you want to do a token transfer today within Anchor, it looks something like this (sorry for leading spaces):

		token::transfer(
			CpiContext::new(
				accs.token_program.to_account_info(),
				Transfer {
					from: accs.user_underlying_token_account.to_account_info(),
					to: accs.vault_underlying_token_account.to_account_info(),
					authority: accs.authority.to_account_info(),
				},
			),
			amount,
		)?;

This is pretty verbose and requires 3 levels of nesting. Not ideal, especially when you compare it with Solidity's ERC20.transferFrom(from, to, amount)

It would be nice to replace the function with something like this:

		token::transfer(
			&accs.token_program,
			&accs.user_underlying_token_account,
			&accs.vault_underlying_token_account,
			amount,
			&accs.authority,
		)?;

[devansh-m12]

I think creating a function might work you can try following code :

pub fn transfer(
    token_program: &AccountInfo,
    user_underlying_token_account: &AccountInfo,
    vault_underlying_token_account: &AccountInfo,
    amount: u64,
    authority: &AccountInfo,
) -> ProgramResult {
    let cpi_ctx = CpiContext::new(
        token_program.clone(),
        Transfer {
            from: user_underlying_token_account.clone(),
            to: vault_underlying_token_account.clone(),
            authority: authority.clone(),
        },
    );
    token::transfer(cpi_ctx, amount)
}

[metaproph3t]

Yeah, this is what I've been doing: example. It would just be nice if we could include this in anchor-spl so I don't need to copypasta into each new repo

[devansh-m12]

If you haven't already, you can make a new pull request for that, and I'm sure they'll integrate it eventually.

[acheroncrypto]

Closing for now: #2596 (comment)