Merge branch 'master' into price-rates

contracts/crowdsale/Crowdsale.sol

@@ -57,7 +57,7 @@ contract Crowdsale {
    * @param wallet Address where collected funds will be forwarded to
    * @param token Address of the token being sold
    */
-  constructor(uint256 rate, address wallet, IERC20 token) public {
+  constructor(uint256 rate, address wallet, IERC20 token) internal {
     require(rate > 0);
     require(wallet != address(0));
     require(token != address(0));
@@ -73,6 +73,9 @@ contract Crowdsale {
 
   /**
    * @dev fallback function ***DO NOT OVERRIDE***
+   * Note that other contracts will transfer fund with a base gas stipend
+   * of 2300, which is not enough to call buyTokens. Consider calling
+   * buyTokens directly when purchasing tokens from a contract.
    */
   function () external payable {
     buyTokens(msg.sender);
@@ -100,15 +103,15 @@ contract Crowdsale {
   }
 
   /**
-   * @return the mount of wei raised.
+   * @return the amount of wei raised.
    */
   function weiRaised() public view returns (uint256) {
     return _weiRaised;
   }
 
   /**
    * @dev low level token purchase ***DO NOT OVERRIDE***
-   * @param beneficiary Address performing the token purchase
+   * @param beneficiary Recipient of the token purchase
    */
   function buyTokens(address beneficiary) public payable {
 
@@ -152,6 +155,7 @@ contract Crowdsale {
     uint256 weiAmount
   )
     internal
+    view
   {
     require(beneficiary != address(0));
     require(weiAmount != 0);
@@ -167,6 +171,7 @@ contract Crowdsale {
     uint256 weiAmount
   )
     internal
+    view
   {
     // optional override
   }
@@ -186,7 +191,7 @@ contract Crowdsale {
   }
 
   /**
-   * @dev Executed when a purchase has been validated and is ready to be executed. Not necessarily emits/sends tokens.
+   * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send tokens.
    * @param beneficiary Address receiving the tokens
    * @param tokenAmount Number of tokens to be purchased
    */

contracts/crowdsale/distribution/FinalizableCrowdsale.sol

@@ -15,7 +15,7 @@ contract FinalizableCrowdsale is TimedCrowdsale {
 
   event CrowdsaleFinalized();
 
-  constructor() public {
+  constructor() internal {
     _finalized = false;
   }
 

contracts/crowdsale/distribution/PostDeliveryCrowdsale.sol

@@ -13,6 +13,8 @@ contract PostDeliveryCrowdsale is TimedCrowdsale {
 
   mapping(address => uint256) private _balances;
 
+  constructor() internal {}
+
   /**
    * @dev Withdraw tokens only after crowdsale ends.
    * @param beneficiary Whose tokens will be withdrawn.

contracts/crowdsale/distribution/RefundableCrowdsale.sol

@@ -22,7 +22,7 @@ contract RefundableCrowdsale is FinalizableCrowdsale {
    * @dev Constructor, creates RefundEscrow.
    * @param goal Funding goal
    */
-  constructor(uint256 goal) public {
+  constructor(uint256 goal) internal {
     require(goal > 0);
     _escrow = new RefundEscrow(wallet());
     _goal = goal;

contracts/crowdsale/emission/AllowanceCrowdsale.sol

@@ -19,7 +19,7 @@ contract AllowanceCrowdsale is Crowdsale {
    * @dev Constructor, takes token wallet address.
    * @param tokenWallet Address holding the tokens, which has approved allowance to the crowdsale
    */
-  constructor(address tokenWallet) public {
+  constructor(address tokenWallet) internal {
     require(tokenWallet != address(0));
     _tokenWallet = tokenWallet;
   }

contracts/crowdsale/emission/MintedCrowdsale.sol

@@ -9,6 +9,7 @@ import "../../token/ERC20/ERC20Mintable.sol";
  * Token ownership should be transferred to MintedCrowdsale for minting.
  */
 contract MintedCrowdsale is Crowdsale {
+  constructor() internal {}
 
   /**
    * @dev Overrides delivery by minting tokens upon purchase.

contracts/crowdsale/price/IncreasingPriceCrowdsale.sol

@@ -20,7 +20,7 @@ contract IncreasingPriceCrowdsale is TimedCrowdsale {
    * @param initialRate Number of tokens a buyer gets per wei at the start of the crowdsale
    * @param finalRate Number of tokens a buyer gets per wei at the end of the crowdsale
    */
-  constructor(uint256 initialRate, uint256 finalRate) public {
+  constructor(uint256 initialRate, uint256 finalRate) internal {
     require(finalRate > 0);
     require(initialRate > finalRate);
     _initialRate = initialRate;
@@ -55,6 +55,10 @@ contract IncreasingPriceCrowdsale is TimedCrowdsale {
    * @return The number of tokens a buyer gets per wei at a given time
    */
   function getCurrentRate() public view returns (uint256) {
+    if (!isOpen()) {
+      return 0;
+    }
+
     // solium-disable-next-line security/no-block-members
     uint256 elapsedTime = block.timestamp.sub(openingTime());
     uint256 timeRange = closingTime().sub(openingTime());

contracts/crowdsale/validation/CappedCrowdsale.sol

@@ -16,7 +16,7 @@ contract CappedCrowdsale is Crowdsale {
    * @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
    * @param cap Max amount of wei to be contributed
    */
-  constructor(uint256 cap) public {
+  constructor(uint256 cap) internal {
     require(cap > 0);
     _cap = cap;
   }
@@ -46,6 +46,7 @@ contract CappedCrowdsale is Crowdsale {
     uint256 weiAmount
   )
     internal
+    view
   {
     super._preValidatePurchase(beneficiary, weiAmount);
     require(weiRaised().add(weiAmount) <= _cap);

contracts/crowdsale/validation/IndividuallyCappedCrowdsale.sol

@@ -14,6 +14,8 @@ contract IndividuallyCappedCrowdsale is Crowdsale, CapperRole {
   mapping(address => uint256) private _contributions;
   mapping(address => uint256) private _caps;
 
+  constructor() internal {}
+
   /**
    * @dev Sets a specific beneficiary's maximum contribution.
    * @param beneficiary Address to be capped
@@ -53,6 +55,7 @@ contract IndividuallyCappedCrowdsale is Crowdsale, CapperRole {
     uint256 weiAmount
   )
     internal
+    view
   {
     super._preValidatePurchase(beneficiary, weiAmount);
     require(

contracts/crowdsale/validation/TimedCrowdsale.sol

@@ -26,10 +26,10 @@ contract TimedCrowdsale is Crowdsale {
    * @param openingTime Crowdsale opening time
    * @param closingTime Crowdsale closing time
    */
-  constructor(uint256 openingTime, uint256 closingTime) public {
+  constructor(uint256 openingTime, uint256 closingTime) internal {
     // solium-disable-next-line security/no-block-members
     require(openingTime >= block.timestamp);
-    require(closingTime >= openingTime);
+    require(closingTime > openingTime);
 
     _openingTime = openingTime;
     _closingTime = closingTime;
@@ -77,6 +77,7 @@ contract TimedCrowdsale is Crowdsale {
   )
     internal
     onlyWhileOpen
+    view
   {
     super._preValidatePurchase(beneficiary, weiAmount);
   }

contracts/mocks/CrowdsaleMock.sol

@@ -0,0 +1,9 @@
+pragma solidity ^0.4.24;
+
+import "../crowdsale/Crowdsale.sol";
+
+contract CrowdsaleMock is Crowdsale {
+  constructor(uint256 rate, address wallet, IERC20 token) public
+    Crowdsale(rate, wallet, token) {
+  }
+}

contracts/mocks/SafeERC20Helper.sol

@@ -3,10 +3,8 @@ pragma solidity ^0.4.24;
 import "../token/ERC20/IERC20.sol";
 import "../token/ERC20/SafeERC20.sol";
 
-contract ERC20FailingMock is IERC20 {
-  function totalSupply() public view returns (uint256) {
-    return 0;
-  }
+contract ERC20FailingMock {
+  uint256 private _allowance;
 
   function transfer(address, uint256) public returns (bool) {
     return false;
@@ -20,19 +18,13 @@ contract ERC20FailingMock is IERC20 {
     return false;
   }
 
-  function balanceOf(address) public view returns (uint256) {
-    return 0;
-  }
-
   function allowance(address, address) public view returns (uint256) {
     return 0;
   }
 }
 
-contract ERC20SucceedingMock is IERC20 {
-  function totalSupply() public view returns (uint256) {
-    return 0;
-  }
+contract ERC20SucceedingMock {
+  uint256 private _allowance;
 
   function transfer(address, uint256) public returns (bool) {
     return true;
@@ -46,12 +38,12 @@ contract ERC20SucceedingMock is IERC20 {
     return true;
   }
 
-  function balanceOf(address) public view returns (uint256) {
-    return 0;
+  function setAllowance(uint256 allowance_) public {
+    _allowance = allowance_;
   }
 
   function allowance(address, address) public view returns (uint256) {
-    return 0;
+    return _allowance;
   }
 }
 
@@ -62,10 +54,12 @@ contract SafeERC20Helper {
   IERC20 private _succeeding;
 
   constructor() public {
-    _failing = new ERC20FailingMock();
-    _succeeding = new ERC20SucceedingMock();
+    _failing = IERC20(new ERC20FailingMock());
+    _succeeding = IERC20(new ERC20SucceedingMock());
   }
 
+  // Using _failing
+
   function doFailingTransfer() public {
     _failing.safeTransfer(address(0), 0);
   }
@@ -78,6 +72,16 @@ contract SafeERC20Helper {
     _failing.safeApprove(address(0), 0);
   }
 
+  function doFailingIncreaseAllowance() public {
+    _failing.safeIncreaseAllowance(address(0), 0);
+  }
+
+  function doFailingDecreaseAllowance() public {
+    _failing.safeDecreaseAllowance(address(0), 0);
+  }
+
+  // Using _succeeding
+
   function doSucceedingTransfer() public {
     _succeeding.safeTransfer(address(0), 0);
   }
@@ -86,7 +90,23 @@ contract SafeERC20Helper {
     _succeeding.safeTransferFrom(address(0), address(0), 0);
   }
 
-  function doSucceedingApprove() public {
-    _succeeding.safeApprove(address(0), 0);
+  function doSucceedingApprove(uint256 amount) public {
+    _succeeding.safeApprove(address(0), amount);
+  }
+
+  function doSucceedingIncreaseAllowance(uint256 amount) public {
+    _succeeding.safeIncreaseAllowance(address(0), amount);
+  }
+
+  function doSucceedingDecreaseAllowance(uint256 amount) public {
+    _succeeding.safeDecreaseAllowance(address(0), amount);
+  }
+
+  function setAllowance(uint256 allowance_) public {
+    ERC20SucceedingMock(_succeeding).setAllowance(allowance_);
+  }
+
+  function allowance() public view returns (uint256) {
+    return _succeeding.allowance(address(0), address(0));
   }
 }

contracts/token/ERC20/ERC20Capped.sol

@@ -24,22 +24,8 @@ contract ERC20Capped is ERC20Mintable {
     return _cap;
   }
 
-  /**
-   * @dev Function to mint tokens
-   * @param to The address that will receive the minted tokens.
-   * @param value The amount of tokens to mint.
-   * @return A boolean that indicates if the operation was successful.
-   */
-  function mint(
-    address to,
-    uint256 value
-  )
-    public
-    returns (bool)
-  {
+  function _mint(address account, uint256 value) internal {
     require(totalSupply().add(value) <= _cap);
-
-    return super.mint(to, value);
+    super._mint(account, value);
   }
-
 }

contracts/token/ERC20/SafeERC20.sol

@@ -10,6 +10,9 @@ import "./IERC20.sol";
  * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
  */
 library SafeERC20 {
+
+  using SafeMath for uint256;
+
   function safeTransfer(
     IERC20 token,
     address to,
@@ -38,6 +41,32 @@ library SafeERC20 {
   )
     internal
   {
+    // safeApprove should only be called when setting an initial allowance, 
+    // or when resetting it to zero. To increase and decrease it, use 
+    // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
+    require((value == 0) || (token.allowance(msg.sender, spender) == 0));
     require(token.approve(spender, value));
   }
+
+  function safeIncreaseAllowance(
+    IERC20 token,
+    address spender,
+    uint256 value
+  )
+    internal
+  {
+    uint256 newAllowance = token.allowance(address(this), spender).add(value);
+    require(token.approve(spender, newAllowance));
+  }
+
+  function safeDecreaseAllowance(
+    IERC20 token,
+    address spender,
+    uint256 value
+  )
+    internal
+  {
+    uint256 newAllowance = token.allowance(address(this), spender).sub(value);
+    require(token.approve(spender, newAllowance));
+  }
 }

contracts/token/ERC721/ERC721.sol

@@ -200,7 +200,7 @@ contract ERC721 is ERC165, IERC721 {
   {
     transferFrom(from, to, tokenId);
     // solium-disable-next-line arg-overflow
-    require(_checkAndCallSafeTransfer(from, to, tokenId, _data));
+    require(_checkOnERC721Received(from, to, tokenId, _data));
   }
 
   /**
@@ -306,7 +306,7 @@ contract ERC721 is ERC165, IERC721 {
    * @param _data bytes optional data to send along with the call
    * @return whether the call correctly returned the expected magic value
    */
-  function _checkAndCallSafeTransfer(
+  function _checkOnERC721Received(
     address from,
     address to,
     uint256 tokenId,

contracts/token/ERC721/ERC721Metadata.sol

@@ -54,7 +54,7 @@ contract ERC721Metadata is ERC165, ERC721, IERC721Metadata {
    * Throws if the token ID does not exist. May return an empty string.
    * @param tokenId uint256 ID of the token to query
    */
-  function tokenURI(uint256 tokenId) public view returns (string) {
+  function tokenURI(uint256 tokenId) external view returns (string) {
     require(_exists(tokenId));
     return _tokenURIs[tokenId];
   }