Refactor eth code: eliminate duplicate address to string conversion functions

[dimxy]

Updated according to the discussion:

In eth.rs we have two public address to string conversion functions: eth_addr_to_hex() and display_eth_address().
PR #2261 also adds a trait AddrToString for the same purpose.
Also, display_eth_address() provides address format with checksum, basically for user input verification.

The required changes:

• Let's use the trait for getting string address for internal purposes and eliminate usage of functions eth_addr_to_hex and display_eth_address (make them private if we still need them).
• Let's use display_eth_address() to return addresses in the API result (to the GUI side). Maybe it's good to implement it as a trait.
• Also eliminate code like: format!("{:#02x}", token_contract_address) and use the unified approach with a trait.

[laruh]

eliminate one of two functions eth_addr_to_hex and display_eth_address.
(I think display_eth_address is what we need. Also let's make it private and use as implementation for the AddrToString::addr_to_string).

We shouldn't use display_eth_address instead of eth_addr_to_hex everywhere when we only need to convert eth Address type to a string. Using display_eth_address in such cases is inefficient, as it unnecessarily computes checksum_address each time, wasting resources.

eth_addr_to_hex and display_eth_address have their own purposes:

komodo-defi-framework/mm2src/coins/eth.rs

Lines 6577 to 6587 in 39515a9

	/// `eth_addr_to_hex` converts Address to hex format.
	/// Note: the result will be in lowercase.
	pub fn eth_addr_to_hex(address: &Address) -> String { format!("{:#02x}", address) }
	/// Checks that input is valid mixed-case checksum form address
	/// The input must be 0x prefixed hex string
	fn is_valid_checksum_addr(addr: &str) -> bool { addr == checksum_address(addr) }
	/// `display_eth_address` converts Address to mixed-case checksum form.
	#[inline]
	pub fn display_eth_address(addr: &Address) -> String { checksum_address(&eth_addr_to_hex(addr)) }

So they are not duplicate conversion functions.

But it still worth making eth_addr_to_hex private and call addr_to_string (AddrToString trait method) instead.

[dimxy]

Using display_eth_address in such cases is inefficient, as it unnecessarily computes checksum_address each time, wasting resources.

Okay, let's ensure we use display_eth_address only for returned results and make this consistently (not like use both addresses with and w/o checksum in results)

BTW I can see the ethereum_types lib has implementation for 'Address' to string conversion. Let's use it maybe.

[laruh]

BTW I can see the ethereum_types lib has implementation for 'Address' to string conversion. Let's use it maybe.

can you provide code part or screenshot so I can find it.

[dimxy]

BTW I can see the ethereum_types lib has implementation for 'Address' to string conversion. Let's use it maybe.

can you provide code part or screenshot so I can find it.

https://github.com/paritytech/parity-common/blob/d54ac847cc5447941390b5e9e5e3baef436e1451/fixed-hash/src/hash.rs#L232