Add ERC165Checker.getSupportedInterfaces

[conspyrosy]

Fixes #2429

See the issue, explained there.

Tests work. Linter giving me line errors in windows

[Amxx]

Thank you @conspyrosy for your PR. We really appreciate feeback from the community, and we appreciate it even more when the community members contributes to the codebase with the feature they see as most relevant to them.

I do believe that, by default, newly allocated arrays should contain 0 (@frangio can you confirme this?), which in boolean terms means false.

If so the getSupportedInterface can be shorten to:

function getSupportedInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool[] memory) {
    // an array of booleans corresponding to interfaceIds and whether they're supported or not
    bool[] memory interfaceIdsSupported = new bool[](interfaceIds.length);
    
    // query support of ERC165 itself
    if (supportsERC165(account)) {
        // query support of each interface in interfaceIds
        for (uint256 i = 0; i < interfaceIds.length; ++i) {
            interfaceIdsSupported[i] = _supportsERC165Interface(account, interfaceIds[i]);
        }
    }
    
    return interfaceIdsSupported;
}

[frangio]

Thanks @conspyrosy!

I do believe that, by default, newly allocated arrays should contain 0 (@frangio can you confirme this?), which in boolean terms means false.

I'm pretty sure this is the case but I couldn't find it in the documentation for Solidity. I've asked the team to confirm.

[frangio]

The reply from the Solidity team was:

at the Solidity level, all newly allocated data structures are guaranteed to be initialized properly. At the assembly level, you cannot rely on 0x40 pointing to zeroed out memory

In summary, yes we can just initialize a new array.

[conspyrosy]

I've only just got round to checking on this, looks like some changes have been made which look good 👍 Let me know if this needs anything from me.

[frangio]

Hi @conspyrosy, no problem. Sorry that we jumped in, we want to ship this in the next release. 🙂

resolved