downloader: implemented new downloader

eth/downloader/peer.go

@@ -0,0 +1,48 @@
+package downloader
+
+import (
+	"math/big"
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+const (
+	workingState = 2
+	idleState    = 4
+)
+
+// peer represents an active peer
+type peer struct {
+	state int
+
+	mu         sync.RWMutex
+	id         string
+	td         *big.Int
+	recentHash common.Hash
+
+	getHashes hashFetcherFn
+	getBlocks blockFetcherFn
+}
+
+// create a new peer
+func newPeer(id string, td *big.Int, hash common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) *peer {
+	return &peer{id: id, td: td, recentHash: hash, getHashes: getHashes, getBlocks: getBlocks, state: idleState}
+}
+
+// fetch a chunk using the peer
+func (p *peer) fetch(chunk *chunk) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	// set working state
+	p.state = workingState
+	// convert the set to a fetchable slice
+	hashes, i := make([]common.Hash, chunk.hashes.Size()), 0
+	chunk.hashes.Each(func(v interface{}) bool {
+		hashes[i] = v.(common.Hash)
+		i++
+		return true
+	})
+	p.getBlocks(hashes)
+}