dex: Pull blocks from blockdb if cache miss (#84)

3 files changed, 40 insertions, 4 deletions

diff --git a/dex/cache.go b/dex/cache.go
index 96ba2d765..c95038e1d 100644
--- a/dex/cache.go
+++ b/dex/cache.go
@@ -21,6 +21,7 @@ import (
 	"sync"
 
 	coreCommon "github.com/dexon-foundation/dexon-consensus/common"
+	coreBlockdb "github.com/dexon-foundation/dexon-consensus/core/blockdb"
 	coreTypes "github.com/dexon-foundation/dexon-consensus/core/types"
 )
 
@@ -47,14 +48,16 @@ type cache struct {
 	blockCache   map[coreCommon.Hash]*coreTypes.Block
 	voteCache    map[coreTypes.Position]map[voteKey]*coreTypes.Vote
 	votePosition []coreTypes.Position
+	db           coreBlockdb.BlockDatabase
 	voteSize     int
 	size         int
 }
 
-func newCache(size int) *cache {
+func newCache(size int, db coreBlockdb.BlockDatabase) *cache {
 	return &cache{
 		blockCache: make(map[coreCommon.Hash]*coreTypes.Block),
 		voteCache:  make(map[coreTypes.Position]map[voteKey]*coreTypes.Vote),
+		db:         db,
 		size:       size,
 	}
 }
@@ -111,6 +114,14 @@ func (c *cache) blocks(hashes coreCommon.Hashes) []*coreTypes.Block {
 	for _, hash := range hashes {
 		if block, exist := c.blockCache[hash]; exist {
 			cacheBlocks = append(cacheBlocks, block)
+		} else {
+			block, err := c.db.Get(hash)
+			if err != nil {
+				continue
+			}
+			// Blocks request from the cache do not need the finalization info.
+			block.Finalization = coreTypes.FinalizationResult{}
+			cacheBlocks = append(cacheBlocks, &block)
 		}
 	}
 	return cacheBlocks
diff --git a/dex/cache_test.go b/dex/cache_test.go
index ac5609c1a..8a0066c94 100644
--- a/dex/cache_test.go
+++ b/dex/cache_test.go
@@ -23,6 +23,7 @@ import (
 	"testing"
 
 	coreCommon "github.com/dexon-foundation/dexon-consensus/common"
+	coreBlockdb "github.com/dexon-foundation/dexon-consensus/core/blockdb"
 	coreTypes "github.com/dexon-foundation/dexon-consensus/core/types"
 )
 
@@ -41,7 +42,11 @@ func (v byHash) Swap(i int, j int) {
 }
 
 func TestCacheVote(t *testing.T) {
-	cache := newCache(3)
+	db, err := coreBlockdb.NewMemBackedBlockDB()
+	if err != nil {
+		panic(err)
+	}
+	cache := newCache(3, db)
 	pos0 := coreTypes.Position{
 		Height: uint64(0),
 	}
@@ -126,7 +131,11 @@ func TestCacheVote(t *testing.T) {
 }
 
 func TestCacheBlock(t *testing.T) {
-	cache := newCache(3)
+	db, err := coreBlockdb.NewMemBackedBlockDB()
+	if err != nil {
+		panic(err)
+	}
+	cache := newCache(3, db)
 	block1 := &coreTypes.Block{
 		Hash: coreCommon.NewRandomHash(),
 	}
@@ -178,4 +187,19 @@ func TestCacheBlock(t *testing.T) {
 	if !hasNewBlock {
 		t.Errorf("expect block %s in cache, have %v", block4, blocks)
 	}
+
+	block5 := &coreTypes.Block{
+		Hash: coreCommon.NewRandomHash(),
+	}
+	if err := db.Put(*block5); err != nil {
+		panic(err)
+	}
+	blocks = cache.blocks(coreCommon.Hashes{block5.Hash})
+	if len(blocks) != 1 {
+		t.Errorf("fail to get blocks: have %d, want 1", len(blocks))
+	} else {
+		if !blocks[0].Hash.Equal(block5.Hash) {
+			t.Errorf("get wrong block: have %s, want %s", blocks[0], block5)
+		}
+	}
 }
diff --git a/dex/handler.go b/dex/handler.go
index 51167c9cb..620320f49 100644
--- a/dex/handler.go
+++ b/dex/handler.go
@@ -53,6 +53,7 @@ import (
 	"github.com/dexon-foundation/dexon/core"
 	"github.com/dexon-foundation/dexon/core/types"
 	"github.com/dexon-foundation/dexon/crypto"
+	"github.com/dexon-foundation/dexon/dex/blockdb"
 	"github.com/dexon-foundation/dexon/dex/downloader"
 	"github.com/dexon-foundation/dexon/dex/fetcher"
 	"github.com/dexon-foundation/dexon/ethdb"
@@ -157,7 +158,7 @@ func NewProtocolManager(
 		nodeTable:       tab,
 		gov:             gov,
 		blockchain:      blockchain,
-		cache:           newCache(128),
+		cache:           newCache(5120, blockdb.NewDatabase(chaindb)),
 		chainconfig:     config,
 		newPeerCh:       make(chan *peer),
 		noMorePeers:     make(chan struct{}),