0g-chain/x/evmutil/spec/02_state.md

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# State
## Parameters and Genesis State
`Parameters` define the list of conversion pairs allowed to be converted between Kava ERC20 tokens & sdk.Coins, and the list of native cosmos sdk.Coins that are allowed to be converted to ERC20s.
```protobuf
// Params defines the evmutil module params
message Params {
// enabled_conversion_pairs defines the list of conversion pairs allowed to be
// converted between Kava ERC20 and sdk.Coin
repeated ConversionPair enabled_conversion_pairs = 4;
// allowed_cosmos_denoms is a list of denom & erc20 token metadata pairs.
// if a denom is in the list, it is allowed to be converted to an erc20 in the evm.
repeated AllowedCosmosCoinERC20Token allowed_cosmos_denoms = 1;
}
// ConversionPair defines a Kava ERC20 address and corresponding denom that is
// allowed to be converted between ERC20 and sdk.Coin
message ConversionPair {
// ERC20 address of the token on the Kava EVM
bytes kava_erc20_address = 1;
// Denom of the corresponding sdk.Coin
string denom = 2;
}
// AllowedCosmosCoinERC20Token defines allowed cosmos-sdk denom & metadata
// for evm token representations of sdk assets.
// NOTE: once evm token contracts are deployed, changes to metadata for a given
// cosmos_denom will not change metadata of deployed contract.
message AllowedCosmosCoinERC20Token {
option (gogoproto.goproto_getters) = false;
// Denom of the sdk.Coin
string cosmos_denom = 1;
// Name of ERC20 contract
string name = 2;
// Symbol of ERC20 contract
string symbol = 3;
// Number of decimals ERC20 contract is deployed with.
uint32 decimals = 4;
}
```
`GenesisState` defines the state that must be persisted when the blockchain stops/restarts in order for normal function of the evmutil module to resume.
```protobuf
message GenesisState {
// previously stored accounts containing fractional balances.
reserved 1;
Params params = 2 [(gogoproto.nullable) = false];
}
```
## Deployed Cosmos Coin Contract Addresses
Addresses for the ERC20 contracts representing cosmos-sdk `Coin`s are kept in the module store. They are stored as bytes by the cosmos-sdk denom they represent.
Example:
If a contract for representing the cosmos-sdk denom `cow` as an ERC20 in the EVM is deployed by the module to the address `0xbeef00000000000000000000000000000000beef`, the module store will contain:
`0x01 | bytes("cow") => bytes(0xbeef00000000000000000000000000000000beef)`
Where `0x01` is the `DeployedCosmosCoinContractKeyPrefix` defined in [keys.go](../types/keys.go).
## Store
For complete implementation details for how items are stored, see [keys.go](../types/keys.go). `x/evmutil` store state consists of accounts and deployed contract addresses.