Improve nsds.Query

namespace/namespace.go

@@ -55,7 +55,9 @@ type datastore struct {
 }
 
 // Query implements Query, inverting keys on the way back out.
+// This function assumes that child datastore.Query returns ordered results
 func (d *datastore) Query(q dsq.Query) (dsq.Results, error) {
+	q.Prefix = d.prefix.Child(ds.NewKey(q.Prefix)).String()
 	qr, err := d.raw.Query(q)
 	if err != nil {
 		return nil, err
@@ -73,7 +75,7 @@ func (d *datastore) Query(q dsq.Query) (dsq.Results, error) {
 				}
 				k := ds.RawKey(r.Entry.Key)
 				if !d.prefix.IsAncestorOf(k) {
-					continue
+					return dsq.Result{}, false
 				}
 
 				r.Entry.Key = d.Datastore.InvertKey(k).String()

namespace/namespace_test.go

@@ -78,6 +78,65 @@ func (ks *DSSuite) testBasic(c *C, prefix string) {
 	}
 }
 
+func (ks *DSSuite) TestQuery(c *C) {
+	mpds := ds.NewMapDatastore()
+	nsds := ns.Wrap(mpds, ds.NewKey("/foo"))
+
+	keys := strsToKeys([]string{
+		"abc/foo",
+		"bar/foo",
+		"foo/bar",
+		"foo/bar/baz",
+		"foo/baz/abc",
+		"xyz/foo",
+	})
+
+	for _, k := range keys {
+		err := mpds.Put(k, []byte(k.String()))
+		c.Check(err, Equals, nil)
+	}
+
+	qres, err := nsds.Query(dsq.Query{})
+	c.Check(err, Equals, nil)
+
+	expect := []dsq.Entry{
+		{Key:"/bar", Value: []byte("/foo/bar")},
+		{Key:"/bar/baz", Value: []byte("/foo/bar/baz")},
+		{Key:"/baz/abc", Value: []byte("/foo/baz/abc")},
+	}
+
+	results, err := qres.Rest()
+	c.Check(err, Equals, nil)
+
+	for i, ent := range results {
+		c.Check(ent.Key, Equals, expect[i].Key)
+		entval, _ := ent.Value.([]byte)
+		expval, _ := expect[i].Value.([]byte)
+		c.Check(string(entval), Equals, string(expval))
+	}
+
+	err = qres.Close()
+	c.Check(err, Equals, nil)
+
+	qres, err = nsds.Query(dsq.Query{Prefix:"bar"})
+	c.Check(err, Equals, nil)
+
+	expect = []dsq.Entry{
+		{Key:"/bar", Value: []byte("/foo/bar")},
+		{Key:"/bar/baz", Value: []byte("/foo/bar/baz")},
+	}
+
+	results, err = qres.Rest()
+	c.Check(err, Equals, nil)
+
+	for i, ent := range results {
+		c.Check(ent.Key, Equals, expect[i].Key)
+		entval, _ := ent.Value.([]byte)
+		expval, _ := expect[i].Value.([]byte)
+		c.Check(string(entval), Equals, string(expval))
+	}
+}
+
 func strsToKeys(strs []string) []ds.Key {
 	keys := make([]ds.Key, len(strs))
 	for i, s := range strs {