blockstore.ErrNotFound, and proper wantlist sorting

blocks/blockstore/blockstore.go

@@ -6,14 +6,16 @@ import (
 	"errors"
 
 	ds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
-
 	mh "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multihash"
+
 	blocks "github.com/jbenet/go-ipfs/blocks"
 	u "github.com/jbenet/go-ipfs/util"
 )
 
 var ValueTypeMismatch = errors.New("The retrieved value is not a Block")
 
+var ErrNotFound = errors.New("blockstore: block not found")
+
 // Blockstore wraps a ThreadSafeDatastore
 type Blockstore interface {
 	DeleteBlock(u.Key) error
@@ -34,6 +36,9 @@ type blockstore struct {
 
 func (bs *blockstore) Get(k u.Key) (*blocks.Block, error) {
 	maybeData, err := bs.datastore.Get(k.DsKey())
+	if err == ds.ErrNotFound {
+		return nil, ErrNotFound
+	}
 	if err != nil {
 		return nil, err
 	}

blockservice/blockservice.go

@@ -8,8 +8,6 @@ import (
 	"fmt"
 
 	context "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"
-
 	blocks "github.com/jbenet/go-ipfs/blocks"
 	"github.com/jbenet/go-ipfs/blocks/blockstore"
 	exchange "github.com/jbenet/go-ipfs/exchange"
@@ -67,7 +65,7 @@ func (s *BlockService) GetBlock(ctx context.Context, k u.Key) (*blocks.Block, er
 		return block, nil
 		// TODO be careful checking ErrNotFound. If the underlying
 		// implementation changes, this will break.
-	} else if err == ds.ErrNotFound && s.Exchange != nil {
+	} else if err == blockstore.ErrNotFound && s.Exchange != nil {
 		log.Debug("Blockservice: Searching bitswap.")
 		blk, err := s.Exchange.GetBlock(ctx, k)
 		if err != nil {

exchange/bitswap/strategy/strategy.go

@@ -68,7 +68,7 @@ func (s *strategist) getSendableBlocks(wantlist *wl.Wantlist, bs bstore.Blocksto
 	var outblocks []*blocks.Block
 	for _, e := range wantlist.Entries() {
 		block, err := bs.Get(e.Value)
-		if err == u.ErrNotFound {
+		if err == bstore.ErrNotFound {
 			continue
 		}
 		if err != nil {

exchange/bitswap/wantlist/wantlist.go

@@ -43,7 +43,7 @@ type entrySlice []*Entry
 
 func (es entrySlice) Len() int           { return len(es) }
 func (es entrySlice) Swap(i, j int)      { es[i], es[j] = es[j], es[i] }
-func (es entrySlice) Less(i, j int) bool { return es[i].Priority < es[j].Priority }
+func (es entrySlice) Less(i, j int) bool { return es[i].Priority > es[j].Priority }
 
 func (w *Wantlist) Entries() []*Entry {
 	var es entrySlice