# GsnUtils

The GSN Solidity Utils Library

Some library functions used throughout the GSN Solidity codebase.

# Functions

# getRelayRequestID(struct GsnTypes.RelayRequest relayRequest, bytes signature)

→ bytes32 (internal)

Calculate an identifier for the meta-transaction in a format similar to a transaction hash. Note that uniqueness relies on signature and may not be enforced if meta-transactions are verified with a different algorithm, e.g. when batching.

relayRequest: The RelayRequest for which an ID is being calculated.

signature: The signature for the RelayRequest. It is not validated here and may even remain empty.

---

# getMethodSig(bytes msgData)

→ bytes4 (internal)

Extract the method identifier signature from the encoded function call.

---

# getParam(bytes msgData, uint256 index)

→ uint256 result (internal)

Extract a parameter from encoded-function block. see: https://solidity.readthedocs.io/en/develop/abi-spec.html#formal-specification-of-the-encoding The return value should be casted to the right type (uintXXX/bytesXXX/address/bool/enum).

msgData: Byte array containing a uint256 value.

index: Index in byte array of uint256 value.

# Return values

uint256 value from byte array.

---

# revertWithData(bytes data)

(internal)

Re-throw revert with the same revert data.

---