dex: replace total difficulty with block number (#73)

In dexon, we don't "mine" and the blockchain won't and shouldn't fork, so
there is no difficulty concept, just replace it with block number.

Note: this commit only replace total difficulty related logic and code
in dex, dex/downloader package.

1 files changed, 2 insertions, 3 deletions

diff --git a/dex/downloader/peer.go b/dex/downloader/peer.go
index b6f2936b7..25c355df1 100644
--- a/dex/downloader/peer.go
+++ b/dex/downloader/peer.go
@@ -23,7 +23,6 @@ import (
 	"errors"
 	"fmt"
 	"math"
-	"math/big"
 	"sort"
 	"sync"
 	"sync/atomic"
@@ -77,7 +76,7 @@ type peerConnection struct {
 
 // LightPeer encapsulates the methods required to synchronise with a remote light peer.
 type LightPeer interface {
-	Head() (common.Hash, *big.Int)
+	Head() (common.Hash, uint64)
 	RequestHeadersByHash(common.Hash, int, int, bool, bool) error
 	RequestHeadersByNumber(uint64, int, int, bool, bool) error
 	RequestGovStateByHash(common.Hash) error
@@ -96,7 +95,7 @@ type lightPeerWrapper struct {
 	peer LightPeer
 }
 
-func (w *lightPeerWrapper) Head() (common.Hash, *big.Int) { return w.peer.Head() }
+func (w *lightPeerWrapper) Head() (common.Hash, uint64) { return w.peer.Head() }
 func (w *lightPeerWrapper) RequestHeadersByHash(h common.Hash, amount int, skip int, reverse, withGov bool) error {
 	return w.peer.RequestHeadersByHash(h, amount, skip, reverse, withGov)
 }