CardstackToken.sol (snippet)

pragma solidity ^0.4.18;

import "zeppelin-solidity/contracts/ownership/Ownable.sol";
import "zeppelin-solidity/contracts/math/SafeMath.sol";
import "./ERC20.sol";
import "./freezable.sol";
import "./CstLedger.sol";
import "./ExternalStorage.sol";
import "./Registry.sol";
import "./CstLibrary.sol";
import "./displayable.sol";
import "./upgradeable.sol";
import "./configurable.sol";
import "./storable.sol";

contract CardstackToken is ERC20,
                           Ownable,
                           freezable,
                           displayable,
                           upgradeable,
                           configurable,
                           storable {

  using SafeMath for uint256;
  using CstLibrary for address;

  ITokenLedger public tokenLedger;
  address public externalStorage;

  .
  .
  .
 
 function totalSupply() public view unlessFrozen unlessUpgraded returns(uint256) {
    return tokenLedger.totalTokens();
  }

  function tokensAvailable() public view unlessFrozen unlessUpgraded returns(uint256) {
    return totalSupply().sub(totalInCirculation());
  }

  function balanceOf(address account) public view unlessUpgraded unlessFrozen returns (uint256) {
    address thisAddress = this;
    if (thisAddress == account) {
      return tokensAvailable();
    } else {
      return tokenLedger.balanceOf(account);
    }
  }

  function transfer(address recipient, uint256 amount) public unlessFrozen unlessUpgraded returns (bool) {
    require(amount > 0);
    require(!frozenAccount[recipient]);

    tokenLedger.transfer(msg.sender, recipient, amount);
    Transfer(msg.sender, recipient, amount);

    return true;
  }

  function mintTokens(uint256 mintedAmount) public onlySuperAdmins unlessFrozen unlessUpgraded returns (bool) {
    tokenLedger.mintTokens(mintedAmount);

    Mint(mintedAmount, tokenLedger.totalTokens(), circulationCap);

    Transfer(address(0), this, mintedAmount);

    return true;
  }

  function grantTokens(address recipient, uint256 amount) public onlySuperAdmins unlessFrozen unlessUpgraded returns (bool) {
    require(!frozenAccount[recipient]);

    tokenLedger.debitAccount(recipient, amount);
    Transfer(this, recipient, amount);

    return true;
  }
  
  .
  .
  .
  
}