Return back filter for tx with TokensSwapped (#335)

monitor/utils/events.js

@@ -11,9 +11,11 @@ const {
   ERC20_ABI,
   ERC677_BRIDGE_TOKEN_ABI,
   getTokenType,
-  getPastEvents
+  getPastEvents,
+  ZERO_ADDRESS
 } = require('../../commons')
 const { normalizeEventInformation } = require('./message')
+const { filterTransferBeforeES } = require('./tokenUtils')
 const { writeFile, readCacheFile } = require('./file')
 
 const {
@@ -109,12 +111,79 @@ async function main(mode) {
       }
     })).map(normalizeEvent)
 
+    let directTransfers = transferEvents
+    const tokensSwappedAbiExists = FOREIGN_ABI.filter(e => e.type === 'event' && e.name === 'TokensSwapped')[0]
+    if (tokensSwappedAbiExists) {
+      logger.debug('collecting half duplex tokens participated in the bridge balance')
+      logger.debug("calling foreignBridge.getPastEvents('TokensSwapped')")
+      const tokensSwappedEvents = await getPastEvents(foreignBridge, {
+        event: 'TokensSwapped',
+        fromBlock: MONITOR_FOREIGN_START_BLOCK,
+        toBlock: foreignBlockNumber
+      })
+
+      // Get token swap events emitted by foreign bridge
+      const bridgeTokensSwappedEvents = tokensSwappedEvents.filter(e => e.address === COMMON_FOREIGN_BRIDGE_ADDRESS)
+
+      // Get transfer events for each previous erc20
+      const uniqueTokenAddressesSet = new Set(bridgeTokensSwappedEvents.map(e => e.returnValues.from))
+
+      // Exclude chai token from previous erc20
+      try {
+        logger.debug('calling foreignBridge.chaiToken() to remove it from half duplex tokens list')
+        const chaiToken = await foreignBridge.methods.chaiToken().call()
+        uniqueTokenAddressesSet.delete(chaiToken)
+      } catch (e) {
+        logger.debug('call to foreignBridge.chaiToken() failed')
+      }
+      // Exclude dai token from previous erc20
+      try {
+        logger.debug('calling foreignBridge.erc20token()  to remove it from half duplex tokens list')
+        const daiToken = await foreignBridge.methods.erc20token().call()
+        uniqueTokenAddressesSet.delete(daiToken)
+      } catch (e) {
+        logger.debug('call to foreignBridge.erc20token() failed')
+      }
+
+      const uniqueTokenAddresses = [...uniqueTokenAddressesSet]
+      await Promise.all(
+        uniqueTokenAddresses.map(async tokenAddress => {
+          const halfDuplexTokenContract = new web3Foreign.eth.Contract(ERC20_ABI, tokenAddress)
+
+          logger.debug('Half duplex token:', tokenAddress)
+          logger.debug("calling halfDuplexTokenContract.getPastEvents('Transfer')")
+          const halfDuplexTransferEvents = (await getPastEvents(halfDuplexTokenContract, {
+            event: 'Transfer',
+            fromBlock: MONITOR_FOREIGN_START_BLOCK,
+            toBlock: foreignBlockNumber,
+            options: {
+              filter: { to: COMMON_FOREIGN_BRIDGE_ADDRESS }
+            }
+          })).map(normalizeEvent)
+
+          // Remove events after the ES
+          logger.debug('filtering half duplex transfers happened before ES')
+          const validHalfDuplexTransfers = await filterTransferBeforeES(halfDuplexTransferEvents)
+
+          transferEvents = [...validHalfDuplexTransfers, ...transferEvents]
+        })
+      )
+
+      // filter transfer that is part of a token swap
+      directTransfers = transferEvents.filter(
+        e =>
+          bridgeTokensSwappedEvents.findIndex(
+            t => t.transactionHash === e.referenceTx && e.recipient === ZERO_ADDRESS
+          ) === -1
+      )
+    }
+
     // Get transfer events that didn't have a UserRequestForAffirmation event in the same transaction
-    transferEvents = transferEvents.filter(
+    directTransfers = directTransfers.filter(
       e => foreignToHomeRequests.findIndex(t => t.referenceTx === e.referenceTx) === -1
     )
 
-    foreignToHomeRequests = [...foreignToHomeRequests, ...transferEvents]
+    foreignToHomeRequests = [...foreignToHomeRequests, ...directTransfers]
   }
 
   logger.debug('Done')

monitor/utils/tokenUtils.js

@@ -0,0 +1,27 @@
+// https://etherscan.io/tx/0xd0c3c92c94e05bc71256055ce8c4c993e047f04e04f3283a04e4cb077b71f6c6
+const blockNumberHalfDuplexDisabled = 9884448
+
+/**
+ * Returns true if the event was before the bridge stopped supporting half duplex transfers.
+ */
+async function transferBeforeES(event) {
+  return event.blockNumber < blockNumberHalfDuplexDisabled
+}
+
+async function filterTransferBeforeES(array) {
+  const newArray = []
+  // Iterate events from newer to older
+  for (let i = array.length - 1; i >= 0; i--) {
+    const beforeES = await transferBeforeES(array[i])
+    if (beforeES) {
+      // add element to first position so the new array will have the same order
+      newArray.unshift(array[i])
+    }
+  }
+  return newArray
+}
+
+module.exports = {
+  filterTransferBeforeES,
+  blockNumberHalfDuplexDisabled
+}