Refact: interfaces of PriceFeedDispatcher and ChainlinkPriceFeedV3

contracts/ChainlinkPriceFeedV3.sol

@@ -5,12 +5,13 @@ import { Address } from "@openzeppelin/contracts/utils/Address.sol";
 import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
 import { AggregatorV3Interface } from "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";
 import { IChainlinkPriceFeed } from "./interface/IChainlinkPriceFeed.sol";
+import { IPriceFeed } from "./interface/IPriceFeed.sol";
 import { IChainlinkPriceFeedV3 } from "./interface/IChainlinkPriceFeedV3.sol";
 import { IPriceFeedUpdate } from "./interface/IPriceFeedUpdate.sol";
 import { BlockContext } from "./base/BlockContext.sol";
 import { CachedTwap } from "./twap/CachedTwap.sol";
 
-contract ChainlinkPriceFeedV3 is IChainlinkPriceFeedV3, IPriceFeedUpdate, BlockContext, CachedTwap {
+contract ChainlinkPriceFeedV3 is IPriceFeed, IChainlinkPriceFeedV3, IPriceFeedUpdate, BlockContext, CachedTwap {
     using SafeMath for uint256;
     using Address for address;
 
@@ -75,7 +76,10 @@ contract ChainlinkPriceFeedV3 is IChainlinkPriceFeedV3, IPriceFeedUpdate, BlockC
         return _lastValidTimestamp;
     }
 
-    /// @inheritdoc IChainlinkPriceFeedV3
+    /// @inheritdoc IPriceFeed
+    /// @dev This is the view version of cacheTwap().
+    ///      If the interval is zero, returns the latest valid price.
+    ///         Else, returns TWAP calculating with the latest valid price and timestamp.
     function getPrice(uint256 interval) external view override returns (uint256) {
         (uint256 latestValidPrice, uint256 latestValidTime) = _getLatestOrCachedPrice();
 
@@ -115,7 +119,7 @@ contract ChainlinkPriceFeedV3 is IChainlinkPriceFeedV3, IPriceFeedUpdate, BlockC
         return _timeout;
     }
 
-    /// @inheritdoc IChainlinkPriceFeedV3
+    /// @inheritdoc IPriceFeed
     function decimals() external view override returns (uint8) {
         return _decimals;
     }

contracts/PriceFeedDispatcher.sol

@@ -6,11 +6,12 @@ import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
 import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
 import { AggregatorV3Interface } from "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";
 import { BlockContext } from "./base/BlockContext.sol";
+import { IPriceFeed } from "./interface/IPriceFeed.sol";
 import { IPriceFeedDispatcher } from "./interface/IPriceFeedDispatcher.sol";
 import { UniswapV3PriceFeed } from "./UniswapV3PriceFeed.sol";
 import { ChainlinkPriceFeedV3 } from "./ChainlinkPriceFeedV3.sol";
 
-contract PriceFeedDispatcher is IPriceFeedDispatcher, Ownable, BlockContext {
+contract PriceFeedDispatcher is IPriceFeed, IPriceFeedDispatcher, Ownable, BlockContext {
     using SafeMath for uint256;
     using Address for address;
 
@@ -57,19 +58,26 @@ contract PriceFeedDispatcher is IPriceFeedDispatcher, Ownable, BlockContext {
     // EXTERNAL VIEW
     //
 
-    /// @inheritdoc IPriceFeedDispatcher
+    /// @inheritdoc IPriceFeed
     function getPrice(uint256 interval) external view override returns (uint256) {
         return getDispatchedPrice(interval);
     }
 
+    /// @inheritdoc IPriceFeedDispatcher
     function getChainlinkPriceFeedV3() external view override returns (address) {
         return address(_chainlinkPriceFeedV3);
     }
 
+    /// @inheritdoc IPriceFeedDispatcher
     function getUniswapV3PriceFeed() external view override returns (address) {
         return address(_uniswapV3PriceFeed);
     }
 
+    //
+    // EXTERNAL PURE
+    //
+
+    /// @inheritdoc IPriceFeed
     function decimals() external pure override returns (uint8) {
         return _DECIMALS;
     }

contracts/interface/IChainlinkPriceFeedV3.sol

@@ -35,13 +35,6 @@ interface IChainlinkPriceFeedV3 is IChainlinkPriceFeedV3Event {
     /// @return timestamp The last cached valid timestamp
     function getLastValidTimestamp() external view returns (uint256 timestamp);
 
-    /// @notice If the interval is zero, returns the latest valid price.
-    ///         Else, returns TWAP calculating with the latest valid price and timestamp.
-    /// @dev This is the view version of cacheTwap()
-    /// @param interval TWAP interval
-    /// @return price The last valid price or TWAP
-    function getPrice(uint256 interval) external view returns (uint256 price);
-
     /// @notice Retrieve the latest price and timestamp from Chainlink aggregator,
     ///         or return the last cached valid price and timestamp if the aggregator hasn't been updated or is frozen.
     /// @return price The latest valid price
@@ -58,7 +51,4 @@ interface IChainlinkPriceFeedV3 is IChainlinkPriceFeedV3Event {
 
     /// @return period The timeout period
     function getTimeout() external view returns (uint256 period);
-
-    /// @return decimals The decimals of price feed
-    function decimals() external view returns (uint8 decimals);
 }

contracts/interface/IPriceFeedDispatcher.sol

@@ -24,10 +24,4 @@ interface IPriceFeedDispatcher is IPriceFeedDispatcherEvent {
     function getChainlinkPriceFeedV3() external view returns (address);
 
     function getUniswapV3PriceFeed() external view returns (address);
-
-    function decimals() external pure returns (uint8);
-
-    /// @dev The same as getDispatchedPrice, it's for backward-compatibility
-    /// @param interval The interval represents twap interval.
-    function getPrice(uint256 interval) external view returns (uint256);
 }