From f0405c6a1decc41a878708b0f80e4b6fd6ebbcd5 Mon Sep 17 00:00:00 2001
From: Jimmy Hu <jimmy.hu@dexon.org>
Date: Thu, 27 Dec 2018 09:17:28 +0800
Subject: dex: add pull randomness (#105)

* vendor: sync to latest core
* dex: Add PullRandomness
---
 dex/cache.go | 62 +++++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 11 deletions(-)

(limited to 'dex/cache.go')

diff --git a/dex/cache.go b/dex/cache.go
index 89bbbe3be..bdc22e114 100644
--- a/dex/cache.go
+++ b/dex/cache.go
@@ -44,21 +44,23 @@ func voteToKey(vote *coreTypes.Vote) voteKey {
 }
 
 type cache struct {
-	lock         sync.RWMutex
-	blockCache   map[coreCommon.Hash]*coreTypes.Block
-	voteCache    map[coreTypes.Position]map[voteKey]*coreTypes.Vote
-	votePosition []coreTypes.Position
-	db           coreDb.Database
-	voteSize     int
-	size         int
+	lock            sync.RWMutex
+	blockCache      map[coreCommon.Hash]*coreTypes.Block
+	voteCache       map[coreTypes.Position]map[voteKey]*coreTypes.Vote
+	randomnessCache map[coreCommon.Hash]*coreTypes.BlockRandomnessResult
+	votePosition    []coreTypes.Position
+	db              coreDb.Database
+	voteSize        int
+	size            int
 }
 
 func newCache(size int, db coreDb.Database) *cache {
 	return &cache{
-		blockCache: make(map[coreCommon.Hash]*coreTypes.Block),
-		voteCache:  make(map[coreTypes.Position]map[voteKey]*coreTypes.Vote),
-		db:         db,
-		size:       size,
+		blockCache:      make(map[coreCommon.Hash]*coreTypes.Block),
+		voteCache:       make(map[coreTypes.Position]map[voteKey]*coreTypes.Vote),
+		randomnessCache: make(map[coreCommon.Hash]*coreTypes.BlockRandomnessResult),
+		db:              db,
+		size:            size,
 	}
 }
 
@@ -126,3 +128,41 @@ func (c *cache) blocks(hashes coreCommon.Hashes) []*coreTypes.Block {
 	}
 	return cacheBlocks
 }
+
+func (c *cache) addRandomness(rand *coreTypes.BlockRandomnessResult) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if len(c.randomnessCache) >= c.size {
+		// Randomly delete one entry.
+		for k := range c.randomnessCache {
+			delete(c.randomnessCache, k)
+			break
+		}
+	}
+	c.randomnessCache[rand.BlockHash] = rand
+}
+
+func (c *cache) randomness(hashes coreCommon.Hashes) []*coreTypes.BlockRandomnessResult {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	cacheRandomnesss := make([]*coreTypes.BlockRandomnessResult, 0, len(hashes))
+	for _, hash := range hashes {
+		if block, exist := c.randomnessCache[hash]; exist {
+			cacheRandomnesss = append(cacheRandomnesss, block)
+		} else {
+			block, err := c.db.GetBlock(hash)
+			if err != nil {
+				continue
+			}
+			if len(block.Finalization.Randomness) == 0 {
+				continue
+			}
+			cacheRandomnesss = append(cacheRandomnesss, &coreTypes.BlockRandomnessResult{
+				BlockHash:  block.Hash,
+				Position:   block.Position,
+				Randomness: block.Finalization.Randomness,
+			})
+		}
+	}
+	return cacheRandomnesss
+}
-- 
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