add last block number for epoch api (#681)

Co-authored-by: Liam Lai <liam@home>

consensus/XDPoS/api.go

@@ -350,13 +350,17 @@ An API exclusively for V2 consensus, designed to assist in getting rewards of th
 Given the epoch number, search the epoch switch block.
 */
 func (api *API) GetBlockInfoByEpochNum(epochNumber uint64) (*utils.EpochNumInfo, error) {
-	result, err := api.XDPoS.EngineV2.GetBlockByEpochNumber(api.chain, epochNumber)
+	thisEpoch, nextEpoch, err := api.XDPoS.EngineV2.GetBlockByEpochNumber(api.chain, epochNumber)
 	if err != nil {
 		return nil, err
 	}
-	return &utils.EpochNumInfo{
-		EpochBlockHash:   result.Hash,
-		EpochRound:       result.Round,
-		EpochBlockNumber: result.Number,
-	}, nil
+	info := &utils.EpochNumInfo{
+		EpochBlockHash:        thisEpoch.Hash,
+		EpochRound:            thisEpoch.Round,
+		EpochFirstBlockNumber: thisEpoch.Number,
+	}
+	if nextEpoch != nil {
+		info.EpochLastBlockNumber = new(big.Int).Sub(nextEpoch.Number, big.NewInt(1))
+	}
+	return info, nil
 }

consensus/XDPoS/engines/engine_v2/utils.go

@@ -220,22 +220,22 @@ func (x *XDPoS_v2) CalculateMissingRounds(chain consensus.ChainReader, header *t
 	return missedRoundsMetadata, nil
 }
 
-func (x *XDPoS_v2) GetBlockByEpochNumber(chain consensus.ChainReader, targetEpochNum uint64) (*types.BlockInfo, error) {
+func (x *XDPoS_v2) GetBlockByEpochNumber(chain consensus.ChainReader, targetEpochNum uint64) (*types.BlockInfo, *types.BlockInfo, error) {
 	currentHeader := chain.CurrentHeader()
 	epochSwitchInfo, err := x.getEpochSwitchInfo(chain, currentHeader, currentHeader.Hash())
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	epochNum := x.config.V2.SwitchBlock.Uint64()/x.config.Epoch + uint64(epochSwitchInfo.EpochSwitchBlockInfo.Round)/x.config.Epoch
 	// since below function GetEpochSwitchInfoBetween(chain, start, end) return nil if start == end, we early return the result
 	if targetEpochNum == epochNum {
-		return epochSwitchInfo.EpochSwitchBlockInfo, nil
+		return epochSwitchInfo.EpochSwitchBlockInfo, nil, nil
 	}
 	if targetEpochNum > epochNum {
-		return nil, errors.New("input epoch number > current epoch number")
+		return nil, nil, errors.New("input epoch number > current epoch number")
 	}
 	if targetEpochNum < x.config.V2.SwitchBlock.Uint64()/x.config.Epoch {
-		return nil, errors.New("input epoch number < v2 begin epoch number")
+		return nil, nil, errors.New("input epoch number < v2 begin epoch number")
 	}
 	epoch := big.NewInt(int64(x.config.Epoch))
 	estblockNumDiff := new(big.Int).Mul(epoch, big.NewInt(int64(epochNum-targetEpochNum)))
@@ -246,13 +246,17 @@ func (x *XDPoS_v2) GetBlockByEpochNumber(chain consensus.ChainReader, targetEpoc
 	estBlockHeader := chain.GetHeaderByNumber(estBlockNum.Uint64())
 	epochSwitchInfos, err := x.GetEpochSwitchInfoBetween(chain, estBlockHeader, currentHeader)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
-	for _, info := range epochSwitchInfos {
+	for i, info := range epochSwitchInfos {
 		epochNum := x.config.V2.SwitchBlock.Uint64()/x.config.Epoch + uint64(info.EpochSwitchBlockInfo.Round)/x.config.Epoch
 		if epochNum == targetEpochNum {
-			return info.EpochSwitchBlockInfo, nil
+			if i < len(epochSwitchInfos)-1 {
+				nextEpoch := epochSwitchInfos[i+1].EpochSwitchBlockInfo
+				return info.EpochSwitchBlockInfo, nextEpoch, nil
+			}
+			return info.EpochSwitchBlockInfo, nil, nil
 		}
 	}
-	return nil, errors.New("input epoch number not found (all rounds in this epoch are missed, which is very rare)")
+	return nil, nil, errors.New("input epoch number not found (all rounds in this epoch are missed, which is very rare)")
 }

consensus/XDPoS/utils/types.go

@@ -74,7 +74,8 @@ type PublicApiMissedRoundsMetadata struct {
 
 // Given an epoch number, this struct records the epoch switch block (first block in epoch) infos such as block number
 type EpochNumInfo struct {
-	EpochBlockHash   common.Hash `json:"hash"`
-	EpochRound       types.Round `json:"round"`
-	EpochBlockNumber *big.Int    `json:"number"`
+	EpochBlockHash        common.Hash `json:"hash"`
+	EpochRound            types.Round `json:"round"`
+	EpochFirstBlockNumber *big.Int    `json:"firstBlock"`
+	EpochLastBlockNumber  *big.Int    `json:"lastBlock"`
 }

consensus/tests/engine_v2_tests/api_test.go

@@ -204,14 +204,20 @@ func TestGetBlockByEpochNumber(t *testing.T) {
 	assert.Nil(t, info)
 
 	info, err = engine.APIs(blockchain)[0].Service.(*XDPoS.API).GetBlockInfoByEpochNum(1)
+	assert.Equal(t, info.EpochFirstBlockNumber.Int64(), int64(901))
+	assert.Equal(t, info.EpochLastBlockNumber.Int64(), int64(1799))
 	assert.Equal(t, info.EpochRound, types.Round(1))
 	assert.Nil(t, err)
 
 	info, err = engine.APIs(blockchain)[0].Service.(*XDPoS.API).GetBlockInfoByEpochNum(2)
+	assert.Equal(t, info.EpochFirstBlockNumber.Int64(), int64(1800))
+	assert.Equal(t, info.EpochLastBlockNumber.Int64(), int64(1802))
 	assert.Equal(t, info.EpochRound, types.Round(900))
 	assert.Nil(t, err)
 
 	info, err = engine.APIs(blockchain)[0].Service.(*XDPoS.API).GetBlockInfoByEpochNum(3)
+	assert.Equal(t, info.EpochFirstBlockNumber.Int64(), int64(1803))
+	assert.Equal(t, info.EpochLastBlockNumber.Int64(), int64(1803))
 	assert.Equal(t, info.EpochRound, types.Round(largeRound))
 	assert.Nil(t, err)
 
@@ -221,6 +227,8 @@ func TestGetBlockByEpochNumber(t *testing.T) {
 
 	info, err = engine.APIs(blockchain)[0].Service.(*XDPoS.API).GetBlockInfoByEpochNum(5)
 	assert.Equal(t, info.EpochRound, types.Round(largeRound2))
+	assert.Equal(t, info.EpochFirstBlockNumber.Int64(), int64(1804))
+	assert.Nil(t, info.EpochLastBlockNumber)
 	assert.Nil(t, err)
 
 	info, err = engine.APIs(blockchain)[0].Service.(*XDPoS.API).GetBlockInfoByEpochNum(6)