Snapshot sync and block gap info in eth_syncing (#2948)

* provide snapshot sync info in eth_syncing

* specify block gap in eth_syncing

* Extend eth_syncing with warp, format the output properly

* adjust serialization tests for sync info

* whitespace

js/src/api/format/output.js

@@ -153,6 +153,28 @@ export function outSignerRequest (request) {
   return request;
 }
 
+export function outSyncing (syncing) {
+  if (syncing && syncing !== 'false') {
+    Object.keys(syncing).forEach((key) => {
+      switch (key) {
+        case 'currentBlock':
+        case 'highestBlock':
+        case 'startingBlock':
+        case 'warpChunksAmount':
+        case 'warpChunksProcessed':
+          syncing[key] = outNumber(syncing[key]);
+          break;
+
+        case 'blockGap':
+          syncing[key] = syncing[key].map(outNumber);
+          break;
+      }
+    });
+  }
+
+  return syncing;
+}
+
 export function outTransaction (tx) {
   if (tx) {
     Object.keys(tx).forEach((key) => {

js/src/api/format/output.spec.js

@@ -16,7 +16,7 @@
 
 import BigNumber from 'bignumber.js';
 
-import { outBlock, outAccountInfo, outAddress, outDate, outHistogram, outNumber, outPeers, outReceipt, outTransaction, outTrace } from './output';
+import { outBlock, outAccountInfo, outAddress, outDate, outHistogram, outNumber, outPeers, outReceipt, outSyncing, outTransaction, outTrace } from './output';
 import { isAddress, isBigNumber, isInstanceOf } from '../../../test/types';
 
 describe('api/format/output', () => {
@@ -203,6 +203,22 @@ describe('api/format/output', () => {
     });
   });
 
+  describe('outSyncing', () => {
+    ['currentBlock', 'highestBlock', 'startingBlock', 'warpChunksAmount', 'warpChunksProcessed'].forEach((input) => {
+      it(`formats ${input} numbers as a number`, () => {
+        expect(outSyncing({ [input]: '0x123' })).to.deep.equal({
+          [input]: new BigNumber('0x123')
+        });
+      });
+    });
+
+    it('formats blockGap properly', () => {
+      expect(outSyncing({ blockGap: [0x123, 0x456] })).to.deep.equal({
+        blockGap: [new BigNumber(0x123), new BigNumber(0x456)]
+      });
+    });
+  });
+
   describe('outTransaction', () => {
     ['from', 'to'].forEach((input) => {
       it(`formats ${input} address as address`, () => {

js/src/api/rpc/eth/eth.js

@@ -15,7 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 import { inAddress, inBlockNumber, inData, inFilter, inHash, inHex, inNumber16, inOptions } from '../../format/input';
-import { outAddress, outBlock, outLog, outNumber, outReceipt, outTransaction } from '../../format/output';
+import { outAddress, outBlock, outLog, outNumber, outReceipt, outSyncing, outTransaction } from '../../format/output';
 
 export default class Eth {
   constructor (transport) {
@@ -314,7 +314,8 @@ export default class Eth {
 
   syncing () {
     return this._transport
-      .execute('eth_syncing');
+      .execute('eth_syncing')
+      .then(outSyncing);
   }
 
   uninstallFilter (filterId) {

js/src/jsonrpc/interfaces/eth.js

@@ -1003,7 +1003,7 @@ export default {
       details: {
         startingBlock: {
           type: Quantity,
-          desc: 'The block at which the import started (will only be reset, after the sync reached his head)'
+          desc: 'The block at which the import started (will only be reset, after the sync reached this head)'
         },
         currentBlock: {
           type: Quantity,
@@ -1012,6 +1012,18 @@ export default {
         highestBlock: {
           type: Quantity,
           desc: 'The estimated highest block'
+        },
+        blockGap: {
+          type: Array,
+          desc: 'Array of "first", "last", such that [first, last) are all missing from the chain'
+        },
+        warpChunksAmount: {
+          type: Quantity,
+          desc: 'Total amount of snapshot chunks'
+        },
+        warpChunksProcessed: {
+          type: Quantity,
+          desc: 'Total amount of snapshot chunks processed'
         }
       }
     }