synapsecns/sanguine

package abiutil

import (
    "fmt"
    "github.com/ethereum/go-ethereum/accounts/abi/bind"
    "github.com/ethereum/go-ethereum/common"
    "strings"
)

// MustGetSelectorByName is a wrapper around `GetSelectorByName` that panics if an error is returned.
func MustGetSelectorByName(name string, metadata *bind.MetaData) [4]byte {
    selector, err := GetSelectorByName(name, metadata)
    if err != nil {
        panic(err)
    }

    return selector
}

// GetSelectorByName takes a function name and a pointer to a `bind.MetaData` object,
// searches for the first function testContract in the `Sigs` map of the metadata object
// that matches the function name, and returns the first four bytes of the keccak256 hash
// of the function testContract as a `[4]byte` array.
func GetSelectorByName(name string, metadata *bind.MetaData) ([4]byte, error) {
    matchingSig, err := GetStringSelectorByName(name, metadata)
    if err != nil {
        return [4]byte{}, err
    }
    // extract the function selector bytes from the only matching testContract
    selectorBytes := common.Hex2Bytes(matchingSig)
    var selector [4]byte
    copy(selector[:], selectorBytes)

    return selector, nil
}

// GetStringSelectorByName takes a function name and a pointer to a `bind.MetaData` object,
// searches for the first function testContract in the `Sigs` map of the metadata object
// that matches the function name, and returns the first four bytes of the keccak256 hash
// of the function testContract as a string.
func GetStringSelectorByName(name string, metadata *bind.MetaData) (string, error) {
    var matchingSigs []string

    // search for function signatures that match the function name
    for sig, desc := range metadata.Sigs {
        if strings.HasPrefix(desc, name+"(") && strings.HasSuffix(desc, ")") {
            matchingSigs = append(matchingSigs, sig)
        }
    }

    if len(matchingSigs) == 0 {
        // if there are no matching signatures, return an error
        return "", fmt.Errorf("no function with name %s", name)
    } else if len(matchingSigs) > 1 {
        // if there are multiple matching signatures, return an error
        return "", fmt.Errorf("multiple functions with name %s", name)
    }

    // extract the function selector bytes from the only matching testContract
    return matchingSigs[0], nil
}