move util.Key into its own package under blocks

blocks/key/key.go

@@ -0,0 +1,114 @@
+package key
+
+import (
+	"encoding/json"
+	"fmt"
+
+	b58 "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-base58"
+	ds "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
+	mh "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multihash"
+)
+
+// Key is a string representation of multihash for use with maps.
+type Key string
+
+// String is utililty function for printing out keys as strings (Pretty).
+func (k Key) String() string {
+	return k.Pretty()
+}
+
+// Pretty returns Key in a b58 encoded string
+// TODO: deprecate Pretty. bad name.
+func (k Key) Pretty() string {
+	return k.B58String()
+}
+
+func (k Key) ToMultihash() mh.Multihash {
+	return mh.Multihash(k)
+}
+
+// B58String returns Key in a b58 encoded string
+func (k Key) B58String() string {
+	return B58KeyEncode(k)
+}
+
+// B58KeyDecode returns Key from a b58 encoded string
+func B58KeyDecode(s string) Key {
+	return Key(string(b58.Decode(s)))
+}
+
+// B58KeyEncode returns Key in a b58 encoded string
+func B58KeyEncode(k Key) string {
+	return b58.Encode([]byte(k))
+}
+
+// DsKey returns a Datastore key
+func (k Key) DsKey() ds.Key {
+	return ds.NewKey(string(k))
+}
+
+// UnmarshalJSON returns a JSON-encoded Key (string)
+func (k *Key) UnmarshalJSON(mk []byte) error {
+	var s string
+	err := json.Unmarshal(mk, &s)
+	if err != nil {
+		return err
+	}
+
+	*k = Key(string(b58.Decode(s)))
+	if len(*k) == 0 && len(s) > 2 { // if b58.Decode fails, k == ""
+		return fmt.Errorf("Key.UnmarshalJSON: invalid b58 string: %v", mk)
+	}
+	return nil
+}
+
+// MarshalJSON returns a JSON-encoded Key (string)
+func (k *Key) MarshalJSON() ([]byte, error) {
+	return json.Marshal(b58.Encode([]byte(*k)))
+}
+
+func (k *Key) Loggable() map[string]interface{} {
+	return map[string]interface{}{
+		"key": k.String(),
+	}
+}
+
+// KeyFromDsKey returns a Datastore key
+func KeyFromDsKey(dsk ds.Key) Key {
+	return Key(dsk.String()[1:])
+}
+
+// B58KeyConverter -- for KeyTransform datastores
+// (static as only one obj needed)
+var B58KeyConverter = b58KeyConverter{}
+
+type b58KeyConverter struct{}
+
+// ConvertKey returns a B58 encoded Datastore key
+// TODO: this is hacky because it encodes every path component. some
+// path components may be proper strings already...
+func (b58KeyConverter) ConvertKey(dsk ds.Key) ds.Key {
+	k := ds.NewKey("/")
+	for _, n := range dsk.Namespaces() {
+		k = k.ChildString(b58.Encode([]byte(n)))
+	}
+	return k
+}
+
+// InvertKey returns a b58 decoded Datastore key
+// TODO: this is hacky because it encodes every path component. some
+// path components may be proper strings already...
+func (b58KeyConverter) InvertKey(dsk ds.Key) ds.Key {
+	k := ds.NewKey("/")
+	for _, n := range dsk.Namespaces() {
+		k = k.ChildString(string(b58.Decode(n)))
+	}
+	return k
+}
+
+// KeySlice is used for sorting Keys
+type KeySlice []Key
+
+func (es KeySlice) Len() int           { return len(es) }
+func (es KeySlice) Swap(i, j int)      { es[i], es[j] = es[j], es[i] }
+func (es KeySlice) Less(i, j int) bool { return es[i] < es[j] }