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Purpose

The token-max-buy-sell-volume rule enforces a limit on the amount of tokens purchased or sold during a certain time period. This rule sets the limit as a percentage of the token’s total supply. The rule will apply to the token designated when a buy or sell action is detected.

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Scope

This rule works at the token level. It must be activated and configured for each token in the corresponding token handler.

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Data Structure

A token-max-buy-sell-volume rule is composed of 4 components:
  • Token Percentage (uint16): The maximum percent in basis units of total supply able to be purchased during the period (i.e. 5050 = 50.50% of total supply).
  • Period (uint16): The length of time for which the rule will apply, in hours.
  • Starting Timestamp (uint64): The unix timestamp of the date when the period starts counting.
  • Total Supply (uint256): if not zero, this value will always be used as the token’s total supply for rule evaluation. This can be used when the amount of circulating supply is much smaller than the amount of the token totalSupply due to some tokens being locked in a dev account or a vesting contract, etc. Only use this value in such cases.
/// ******** Token Max Buy Sell Volume Rules ********
struct TokenMaxBuySellVolume {
    uint16 tokenPercentage; /// from 0000 to 10000 => 0.00% to 100.00%.
    uint16 period;
    uint256 totalSupply; /// set 0 to use erc20 totalSupply
    uint64 startTime; ///start of time period for the rule
}
see RuleDataInterfaces
The token-max-buy-sell-volume rules are stored in a mapping indexed by ruleId(uint32) in order of creation: 
/// ******** Token Max Buy Volume ********
struct TokenMaxBuySellVolumeS {
    mapping(uint32 => INonTaggedRules.TokenMaxBuySellVolume) tokenMaxBuySellVolumeRules;
    uint32 tokenMaxBuySellVolumeIndex;
}
see IRuleStorage

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Configuration and Enabling/Disabling

  • This rule can only be configured in the protocol by a rule administrator.
  • This rule can only be set in the asset handler by a rule administrator.
  • This rule can only be activated/deactivated in the asset handler by a rule administrator.
  • This rule can only be updated in the asset handler by a rule administrator.

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Rule Evaluation

The rule will be evaluated with the following logic:
  1. The handler determines if the rule is active from the supplied action. If not, processing does not continue past this step.
  2. The token handler decides if the transfer is a buy or sell (user perspective). If it is, it continues with the next steps.
  3. The processor receives the ID of the token-max-buy-volume rule set in the asset handler.
  4. The processor receives the current total purchased or sold within period, token A amount (total amount of token A being transferred in the current transaction), previous purchase or sell time, and token’s total supply from the handler.
  5. The processor evaluates whether the rule has a set total supply or uses the token’s total supply provided by the handler set at the beginning of every new period.
  6. The processor evaluates whether the current time is within a new period.
    • If it is a new period, the processor sets the percent of total supply to the token A amount.
    • If it is not a new period, the processor sets percent of total supply to the sum of the total purchased within period and token A amount.
  7. The processor calculates the final purchase or sale percentage, in basis units, using the percent of total supply calculated in step 4 and the total supply set in step 3.
  8. The processor evaluates if the final purchase or sale percentage of total supply would be greater than the token percentage.
    • If yes, the transaction reverts.
    • If no, the processor returns the token percentage value for the current period to the handler.
  9. If it’s a non-custodial style Buy
    1. When the Sell action is also active, checks steps 4-9 for sell volume.
  10. If it’s a non-custodial style Sell
    1. When the Buy action is also active, checks steps 4-9 for buy volume.
The list of available actions rules can be applied to can be found at ACTION_TYPES
see ERC20RuleProcessorFacet -> checkTokenMaxBuySellVolume

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Evaluation Exceptions

This rule doesn’t apply when:
  • An approved Trading-Rule approved address is in the to side of the transaction.
  • a treasury account is in the from or to side of the transaction.

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Revert Message

The rule processor will revert with the following error if the rule check fails: 
error OverMaxVolume();
The selector for this error is 0xfa006f25.

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Create Function

Adding a token-max-buy-sell-volume rule is done through the function: 
function addTokenMaxBuySellVolume(
    address _appManagerAddr,
    uint16 _supplyPercentage,
    uint16 _period,
    uint256 _totalSupply,
    uint64 _startTime
) external ruleAdministratorOnly(_appManagerAddr) returns (uint32);
see RuleDataFacet
The add function will return the protocol ID of the rule.

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Parameters:

  • _appManagerAddr (address): The address of the application manager to verify that the caller has Rule administrator privileges.
  • _supplyPercentage (uint16): Maximum allowable percentage (in basis unit) of buy or sell volume per period.
  • _period (uint16): The amount of hours per period.
  • _startTime (uint64): Unix timestamp for the _period to start counting.
  • _totalSupply (uint256): (optional) if not 0, then this is the value used for totalSupply instead of the live token’s totalSupply value at rule processing time.

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Parameter Optionality:

The parameters where developers have the options are:
  • _totalSupply: For purchase volume over supply calculations, when this is zero, the token’s totalSupply is used. Otherwise, this value is used as the total supply.

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Parameter Validation:

The following validation will be carried out by the add function in order to ensure that these parameters are valid and make sense:
  • _appManagerAddr is not the zero address.
  • _supplyPercentage_ is not greater than 9999 (99.99%).
  • _supplyPercentage and _period are greater than a value of 0.
  • _startTime is not zero and is not more than 52 weeks in the future.
see RuleDataFacet

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Other Functions:

  • In Protocol Rule Processor:
    • Function to get a rule by its ID: 
      function getTokenMaxBuySellVolume(
    uint32 _index
    )
    external
    view
    returns
    (NonTaggedRules.TokenMaxBuySellVolume memory);
    • Function to get current amount of rules in the protocol: 
      function getTotalTokenMaxBuySellVolume() public view returns (uint32);
  • In Protocol Rule Processor:
    • Function that evaluates the rule: 
      function checkTokenMaxBuySellVolume(
        uint32 ruleId,
        uint256 currentTotalSupply,
        uint256 amountToTransfer,
        uint64 lastPurchaseTime,
        uint256 boughtInPeriod
    )
    external
    view
    returns (uint256);
  • in ERC20Handler, ERC721Handler:
    • Function to set and activate at the same time the rule for the supplied actions in an asset handler: 
      function setTokenMaxBuySellVolumeId(ActionTypes[] calldata _actions, uint32 _ruleId) external ruleAdministratorOnly(appManagerAddress);
    • Function to activate/deactivate the rule for the supplied actions in an asset handler: 
      function activateTokenMaxBuySellVolume(ActionTypes[] calldata _actions, bool _on) external ruleAdministratorOnly(appManagerAddress);
    • Function to know the activation state of the rule for the supplied action in an asset handler: 
      function isTokenMaxBuySellVolumeActive(ActionTypes _action) external view returns (bool);
    • Function to get the rule Id for the supplied action from an asset handler: 
      function getTokenMaxBuySellVolumeId(ActionTypes _action) external view returns (uint32);

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Return Data

This rule returns the value:
  1. Total Within Period (uint256): the updated value for the total traded volume during the period for the determined action type.
uint256 boughtInPeriod;

uint256 salesInPeriod;
see Token Handler Trading Rule Facet

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Data Recorded

This rule requires recording of the following information in the asset handler: For buy actions:
  • Total Purchased Within Period (uint256): the updated value for the total purchased during the period.
  • Previous Purchase Time (uint64): the Unix timestamp of the last update in the Last-Transfer-Time variable
uint64 private previousPurchaseTime;
uint256 private totalBoughtInPeriod;
For sell actions:
  • Total Sold Within Period (uint256): the updated value for the total sold during the period.
  • Previous Sell Time (uint64): the Unix timestamp of the last update in the Last-Transfer-Time variable
uint64 private previousSellTime;
uint256 private totalSoldInPeriod;
see Token Handler Trading Rule Facet NOTE: When this rule is updated and/or deactivated, the recorded data is cleared. When the rule is reactivated or set to a new ruleId, the recorded data will start in its default state.

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Events

  • event AD1467_ProtocolRuleCreated(bytes32 indexed ruleType, uint32 indexed ruleId, bytes32[] extraTags):
    • Emitted when: the rule has been created in the protocol.
    • Parameters:
      • ruleType: “TOKEN_MAX_BUY_SELL_VOLUME”.
      • ruleId: the index of the rule created in the protocol by rule type.
      • extraTags: an empty array.
  • event AD1467_ApplicationHandlerActionApplied(bytes32 indexed ruleType, ActionTypes action, uint32 indexed ruleId):
    • Emitted when: rule has been applied in an asset handler.
    • parameters:
      • ruleType: “TOKEN_MAX_BUY_SELL_VOLUME”.
      • action: the protocol action the rule is being applied to.
      • ruleId: the index of the rule created in the protocol by rule type.
  • event AD1467_ApplicationHandlerActionActivated(bytes32 indexed ruleType, ActionTypes actions, uint256 indexed ruleId)
    • Emitted when: a Transfer counter rule has been activated in an asset handler:
    • Parameters:
      • ruleType: “TOKEN_MAX_BUY_SELL_VOLUME”.
      • actions: the protocol actions for which the rule is being activated.
      • ruleId: a placeholder of 0 will be passed for ruleId
  • event AD1467_ApplicationHandlerActionDeactivated(bytes32 indexed ruleType, ActionTypes actions, uint256 indexed ruleId)
    • Emitted when: a Transfer counter rule has been deactivated in an asset handler:
    • Parameters:
      • ruleType: “TOKEN_MAX_BUY_SELL_VOLUME”.
      • actions: the protocol actions for which the rule is being deactivated.
      • ruleId: a placeholder of 0 will be passed for ruleId

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Dependencies

  • This rule has no dependencies.