Contract Management

This document describes the design of the freezing/unfreezing operations(referred to as contract lift cycle status management operation on below) and their operation permissions in contract life cycle management.

Important

The contract life cycle management operation on the contract supports storagestate storage mode, but not mptstate storage mode.The contracts mentioned here are only Solidity contracts and do not include pre-compiled contracts currently.

noun explanation

Contract management related operations include freezeContract, unfreezeContract, grantContractStatusManager, getContractStatus, listContractStatusManager.

• freezeContract : Reversible operation, the interfaces of a frozen contract can not be called

• unfreezeContract : Undo the freezeContract operation, the interfaces of an unfrozen contract can be called

• getContractStatus : Query the status of a contract to return the status of available/frozen

• grantContractStatusManager : Grant the account’s permission of contract status managememt

• listContractStatusManager : Query a list of authorized accounts that can manage a specified contract

Important

The operation of freezing a contract will not modify the original contract content, including logic and data, and will only be recorded through a field.

The state transition moments are shown below:

	available	frozen
freeze	Success	Fail
unfreeze	Fail	Success

Implementation

Record of Contract status

• A new field frozen is used to record whether the contract has been frozen. The default of this field is false, indicating that it is available. When frozen, the value is true.

• A new field authority is used to record accounts that can manage contract status. Each account with permission corresponds to one line of authority records.

Note:

1. False will be returned when querying the field for the contract table with no field frozen;

2. When a contract is deployed, the tx.origin will be written to field authority by default.

3. When an interface of contract A was called to create contract B, the tx.origin and the authorization of contract A is written to field authority of contract B by default.

Judgment of contract status

In the Executive module, the values of frozen fields are obtained according to the address of a contract, and the transaction will be executed smoothly, or an exception is thrown to indicate that the contract has been frozen after judgment.

Judgment of authority

• The authority to update contract status needs to be determined. Only the accounts in authority list can set the contract status;

• The authority to grant authorization needs to be determined. Only the account in the authority list can grant other accounts the authorization to manage the contract;

• Any account can query contract status and authorization list.

Interfaces of contract life cycle management

A contract life cycle management precompiled named ContractLifeCyclePrecompiled is added with 0x1007 address, which is used to set and query contract status.

contract ContractLifeCyclePrecompiled {
    function freeze(address addr) public returns(int);
    function unfreeze(address addr) public returns(int);
    function grantManager(address contractAddr, address userAddr) public returns(int);
    function getStatus(address addr) public constant returns(uint,string);
    function listManager(address addr) public constant returns(uint,address[]);
}

Description of return code

code	message
0	success
-51900	the contract has been frozen
-51901	the contract is available
-51902	the contract has been granted authorization with same user
-51903	the contract address is invalid
-51904	the address is not exist
-51905	this operation has no permissions

Important

Contract management related operations can only be performed on 2.3 and above.