Extract exitFee

contracts/ContinuousOffering.sol

@@ -43,9 +43,6 @@ contract ContinuousOffering
     address indexed _from,
     uint _fairValue
   );
-  event Close(
-    uint _exitFee
-  );
   event StateChange(
     uint _previousState,
     uint _newState
@@ -935,63 +932,16 @@ contract ContinuousOffering
 
   /// Close
 
-  function estimateExitFee(
-    uint _msgValue
-  ) public view
-    returns(uint)
-  {
-    uint exitFee;
-
-    if(state == STATE_RUN)
-    {
-      uint reserve = buybackReserve();
-      reserve = reserve.sub(_msgValue);
-
-      // Source: t*(t+b)*(n/d)-r
-      // Implementation: (b n t)/d + (n t^2)/d - r
-
-      uint _totalSupply = totalSupply();
-
-      // Math worst case:
-      // MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE/2 * MAX_BEFORE_SQUARE
-      exitFee = BigDiv.bigDiv2x1(
-        _totalSupply,
-        burnedSupply * buySlopeNum,
-        buySlopeDen
-      );
-      // Math worst case:
-      // MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE
-      exitFee += BigDiv.bigDiv2x1(
-        _totalSupply,
-        buySlopeNum * _totalSupply,
-        buySlopeDen
-      );
-      // Math: this if condition avoids a potential overflow
-      if(exitFee <= reserve)
-      {
-        exitFee = 0;
-      }
-      else
-      {
-        exitFee -= reserve;
-      }
-    }
-
-    return exitFee;
-  }
-
   /// @notice Called by the beneficiary account to STATE_CLOSE or STATE_CANCEL the c-org,
   /// preventing any more tokens from being minted.
   /// @dev Requires an `exitFee` to be paid.  If the currency is ETH, include a little more than
   /// what appears to be required and any remainder will be returned to your account.  This is
   /// because another user may have a transaction mined which changes the exitFee required.
   /// For other `currency` types, the beneficiary account will be billed the exact amount required.
-  function close() public payable
+  function _close() internal
   {
     require(msg.sender == beneficiary, "BENEFICIARY_ONLY");
 
-    uint exitFee = 0;
-
     if(state == STATE_INIT)
     {
       // Allow the org to cancel anytime if the initGoal was not reached.
@@ -1004,19 +954,13 @@ contract ContinuousOffering
       require(MAX_UINT - minDuration > runStartedOn, "MAY_NOT_CLOSE");
       require(minDuration + runStartedOn <= block.timestamp, "TOO_EARLY");
 
-      exitFee = estimateExitFee(msg.value);
-
       emit StateChange(state, STATE_CLOSE);
       state = STATE_CLOSE;
-
-      _collectInvestment(msg.sender, exitFee, msg.value, true);
     }
     else
     {
       revert("INVALID_STATE");
     }
-
-    emit Close(exitFee);
   }
 
   // --- Approve by signature ---

contracts/DecentralizedAutonomousTrust.sol

@@ -14,11 +14,81 @@ import "./ContinuousOffering.sol";
  */
 contract DecentralizedAutonomousTrust is ContinuousOffering
 {
+  event Close(
+    uint _exitFee
+  );
   event Pay(
     address indexed _from,
     uint _currencyValue
   );
 
+  /// Close
+
+  function estimateExitFee(
+    uint _msgValue
+  ) public view
+    returns(uint)
+  {
+    uint exitFee;
+
+    if(state == STATE_RUN)
+    {
+      uint reserve = buybackReserve();
+      reserve = reserve.sub(_msgValue);
+
+      // Source: t*(t+b)*(n/d)-r
+      // Implementation: (b n t)/d + (n t^2)/d - r
+
+      uint _totalSupply = totalSupply();
+
+      // Math worst case:
+      // MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE/2 * MAX_BEFORE_SQUARE
+      exitFee = BigDiv.bigDiv2x1(
+        _totalSupply,
+        burnedSupply * buySlopeNum,
+        buySlopeDen
+      );
+      // Math worst case:
+      // MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE
+      exitFee += BigDiv.bigDiv2x1(
+        _totalSupply,
+        buySlopeNum * _totalSupply,
+        buySlopeDen
+      );
+      // Math: this if condition avoids a potential overflow
+      if(exitFee <= reserve)
+      {
+        exitFee = 0;
+      }
+      else
+      {
+        exitFee -= reserve;
+      }
+    }
+
+    return exitFee;
+  }
+
+  /// @notice Called by the beneficiary account to STATE_CLOSE or STATE_CANCEL the c-org,
+  /// preventing any more tokens from being minted.
+  /// @dev Requires an `exitFee` to be paid.  If the currency is ETH, include a little more than
+  /// what appears to be required and any remainder will be returned to your account.  This is
+  /// because another user may have a transaction mined which changes the exitFee required.
+  /// For other `currency` types, the beneficiary account will be billed the exact amount required.
+  function close() public payable
+  {
+    uint exitFee = 0;
+
+    if(state == STATE_RUN)
+    {
+      exitFee = estimateExitFee(msg.value);
+      _collectInvestment(msg.sender, exitFee, msg.value, true);
+    }
+
+    super._close();
+    emit Close(exitFee);
+  }
+
   /// Pay
 
   /// @dev Pay the organization on-chain.