# Contract Interface

## transferOut

OmniService transfer out of message data

**Note: `transferOut` will be deprecated, it is recommended to use `messageOut` instead.**

#### function

```
function transferOut(
    uint256 _toChain,
    bytes memory _messageData,
    address _feeToken
) external payable virtual returns (bytes32);
```

#### parameters

| parameter     | type    | comment                                                         |
| ------------- | ------- | --------------------------------------------------------------- |
| \_toChain     | uint256 | Target chain id to transfer out                                 |
| \_messageData | bytes   | This is the information encoded from `MessageData`              |
| \_feeToken    | address | This is the address of the token you want to use to pay the fee |

#### Return Value

| type    | comment                                 |
| ------- | --------------------------------------- |
| bytes32 | The order ID of the cross-chain message |

## messageOut

OnmiService sends a cross-chain message

#### Function

```
function messageOut(
	bytes32 _transferId,
	address _initiator,
	address _referrer,
	uint256 _toChain,    
	bytes memory _messageData,    
	address _feeToken
) external payable virtual returns (bytes32);
```

#### Parameters

| parameter     | type    | comment                                                                                  |
| ------------- | ------- | ---------------------------------------------------------------------------------------- |
| \_transferId  | bytes32 | Custom identifier provided by the caller                                                 |
| \_initiator   | address | The actual address of the message initiator, which is typically a user address           |
| \_referrer    | address | Custom parameter provided by the caller, which can serve as an identifier for the caller |
| \_toChain     | uint256 | The chain id of the target chain                                                         |
| \_messageData | bytes   | This is the information encoded from `MessageData`                                       |
| \_feeToken    | address | This is the address of the token you want to use to pay the fee                          |

#### Return Value

| type    | comment                                 |
| ------- | --------------------------------------- |
| bytes32 | The order ID of the cross-chain message |

## retryMessageIn

When a message execution fails, the contract stores the hash of the relevant information. Passing the corresponding parameters allows for retrying the execution of the cross-chain message.

#### Function

```
function retryMessageIn(
    uint256 _fromChain,
    bytes32 _orderId,
    bytes calldata _fromAddress,
    bytes calldata _messageData
) external;
```

#### Parameters

| parameter     | type    | comment                                                 |
| ------------- | ------- | ------------------------------------------------------- |
| \_orderId     | bytes32 | The order ID of the cross-chain message                 |
| \_fromChain   | uint256 | The chain ID of the source chain                        |
| \_fromAddress | bytes   | The address of the source chain                         |
| \_messageData | bytes   | This is the `messageData` validated by the source chain |

## getMessageFee

Get the specific fee for the target chain.

#### Function

```
function getMessageFee(    
	uint256 _toChain,    
	address _feeToken,    
	uint256 _gasLimit
) external view returns(uint256 amount, address receiverAddress);
```

#### Parameters

| parameter  | type    | comment                                                         |
| ---------- | ------- | --------------------------------------------------------------- |
| \_toChain  | uint256 | The chain id of the target chain                                |
| \_feeToken | address | This is the address of the token you want to use to pay the fee |
| \_gasLimit | uint256 | Customizable gas limit                                          |

#### Return Value

| value           | type    | comment                            |
| --------------- | ------- | ---------------------------------- |
| amount          | uint256 | The amount of the fee              |
| receiverAddress | address | The address that receives the fee. |

## CallData Interface

### addRemoteCaller

Granting the source chain the chain ID and address permissions to execute messages.

#### Function

```
function addRemoteCaller(uint256 _fromChain, bytes memory _fromAddress, bool _tag) external;
```

#### Parameters

| parameter     | type    | comment                                                                   |
| ------------- | ------- | ------------------------------------------------------------------------- |
| \_fromChain   | uint256 | The chain ID of the source chain                                          |
| \_fromAddress | bytes   | The address of the source chain                                           |
| \_tag         | bool    | True indicates permission granted, false indicates permission not granted |

### getExecutePermission

To check if the source chain's chain ID and address have permission to execute cross-chain messages on the target chain:

* True means permission is granted (可以执行).
* False means permission is not granted (不行).

#### Function

```
function getExecutePermission(    
	address _targetAddress,    
	uint256 _fromChain,    
	bytes memory _fromAddress
) external view override returns (bool)
```

#### Parameters

| parameter       | type    | comment                                  |
| --------------- | ------- | ---------------------------------------- |
| \_targetAddress | address | The contract address on the target chain |
| \_fromChain     | uint256 | The chain id of the target chain         |
| \_fromAddress   | bytes   | The address of the source chain          |

#### Return Value

| type | comment                                                                    |
| ---- | -------------------------------------------------------------------------- |
| bool | True indicates permission granted, false indicates permission not granted. |


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