refactor(util) move block generator

@whyrusleeping @jbenet

Putting the block generator in a util dir until blocks.

Can't put it in util/testutil because the util/testutil/dag-generator
imports blockservice and blockservice uses the generator.

Tough problem. This'll do for now.

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

blocks/blocksutil/block_generator.go

+package blocksutil
+
+import "github.com/jbenet/go-ipfs/blocks"
+
+func NewBlockGenerator() BlockGenerator {
+	return BlockGenerator{}
+}
+
+type BlockGenerator struct {
+	seq int
+}
+
+func (bg *BlockGenerator) Next() *blocks.Block {
+	bg.seq++
+	return blocks.NewBlock([]byte(string(bg.seq)))
+}
+
+func (bg *BlockGenerator) Blocks(n int) []*blocks.Block {
+	blocks := make([]*blocks.Block, 0)
+	for i := 0; i < n; i++ {
+		b := bg.Next()
+		blocks = append(blocks, b)
+	}
+	return blocks
+}

blockservice/blocks_test.go

@@ -10,6 +10,7 @@ import (
 	dssync "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore/sync"
 	blocks "github.com/jbenet/go-ipfs/blocks"
 	blockstore "github.com/jbenet/go-ipfs/blocks/blockstore"
+	blocksutil "github.com/jbenet/go-ipfs/blocks/blocksutil"
 	bitswap "github.com/jbenet/go-ipfs/exchange/bitswap"
 	tn "github.com/jbenet/go-ipfs/exchange/bitswap/testnet"
 	offline "github.com/jbenet/go-ipfs/exchange/offline"
@@ -66,7 +67,7 @@ func TestGetBlocksSequential(t *testing.T) {
 	net := tn.VirtualNetwork()
 	rs := mock.VirtualRoutingServer()
 	sg := bitswap.NewSessionGenerator(net, rs)
-	bg := bitswap.NewBlockGenerator()
+	bg := blocksutil.NewBlockGenerator()
 
 	instances := sg.Instances(4)
 	blks := bg.Blocks(50)

exchange/bitswap/bitswap_test.go

@@ -7,8 +7,8 @@ import (
 	"time"
 
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
-
 	blocks "github.com/jbenet/go-ipfs/blocks"
+	blocksutil "github.com/jbenet/go-ipfs/blocks/blocksutil"
 	tn "github.com/jbenet/go-ipfs/exchange/bitswap/testnet"
 	peer "github.com/jbenet/go-ipfs/peer"
 	mock "github.com/jbenet/go-ipfs/routing/mock"
@@ -20,7 +20,7 @@ func TestClose(t *testing.T) {
 	vnet := tn.VirtualNetwork()
 	rout := mock.VirtualRoutingServer()
 	sesgen := NewSessionGenerator(vnet, rout)
-	bgen := NewBlockGenerator()
+	bgen := blocksutil.NewBlockGenerator()
 
 	block := bgen.Next()
 	bitswap := sesgen.Next()
@@ -124,7 +124,7 @@ func PerformDistributionTest(t *testing.T, numInstances, numBlocks int) {
 	net := tn.VirtualNetwork()
 	rs := mock.VirtualRoutingServer()
 	sg := NewSessionGenerator(net, rs)
-	bg := NewBlockGenerator()
+	bg := blocksutil.NewBlockGenerator()
 
 	t.Log("Test a few nodes trying to get one file with a lot of blocks")
 
@@ -184,7 +184,7 @@ func TestSendToWantingPeer(t *testing.T) {
 	net := tn.VirtualNetwork()
 	rs := mock.VirtualRoutingServer()
 	sg := NewSessionGenerator(net, rs)
-	bg := NewBlockGenerator()
+	bg := blocksutil.NewBlockGenerator()
 
 	me := sg.Next()
 	w := sg.Next()

exchange/bitswap/testutils.go

@@ -4,7 +4,6 @@ import (
 	"github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
 	ds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
 	ds_sync "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore/sync"
-	"github.com/jbenet/go-ipfs/blocks"
 	"github.com/jbenet/go-ipfs/blocks/blockstore"
 	"github.com/jbenet/go-ipfs/exchange"
 	tn "github.com/jbenet/go-ipfs/exchange/bitswap/testnet"
@@ -12,35 +11,6 @@ import (
 	"github.com/jbenet/go-ipfs/routing/mock"
 )
 
-/*
-TODO: This whole file needs somewhere better to live.
-The issue is that its very difficult to move it somewhere else
-without creating circular dependencies.
-Additional thought required.
-*/
-
-func NewBlockGenerator() BlockGenerator {
-	return BlockGenerator{}
-}
-
-type BlockGenerator struct {
-	seq int
-}
-
-func (bg *BlockGenerator) Next() *blocks.Block {
-	bg.seq++
-	return blocks.NewBlock([]byte(string(bg.seq)))
-}
-
-func (bg *BlockGenerator) Blocks(n int) []*blocks.Block {
-	blocks := make([]*blocks.Block, 0)
-	for i := 0; i < n; i++ {
-		b := bg.Next()
-		blocks = append(blocks, b)
-	}
-	return blocks
-}
-
 func NewSessionGenerator(
 	net tn.Network, rs mock.RoutingServer) SessionGenerator {
 	return SessionGenerator{