datastore: Update AllocateIDs to take keys.

service/datastore/key.go

Index: service/datastore/key.go
diff --git a/service/datastore/key.go b/service/datastore/key.go
index 2071bfb7b2ad01ceed9c42592d5d6ba01fb6b053..7cabd3e3db8c337e01a6a6a8dceb811042bed3b1 100644
--- a/service/datastore/key.go
+++ b/service/datastore/key.go
@@ -414,20 +414,51 @@ func (k *Key) GQL() string {
 }
 
 // Equal returns true iff the two keys represent identical key values.
-func (k *Key) Equal(other *Key) (ret bool) {
+func (k *Key) Equal(other *Key) bool {
+	return k.SameKind(other) && (k.LastTok() == other.LastTok())
+}
+
+// SameKind asserts that other refers to the same entity as k. This checks the
+// full lineage of the key.
+func (k *Key) SameKind(other *Key) (ret bool) {

[iannucci, 2016/06/14 01:46:04]

This terminology is misleading. Kind means something else for Keys.
IncompleteEqual would be (maybe) clearer. e.g. 'if these were both incomplete
keys, would they be equal?'

[dnj (Google), 2016/06/14 04:24:18]

Done.

 	ret = (k.appID == other.appID &&
 		k.namespace == other.namespace &&
 		len(k.toks) == len(other.toks))
 	if ret {
 		for i, t := range k.toks {
-			if ret = t == other.toks[i]; !ret {
-				return
+			if i == len(k.toks)-1 {
+				// Last token: check only Kind.
+				if ret = (t.Kind == other.toks[i].Kind); !ret {
+					return
+				}
+			} else {
+				if ret = t == other.toks[i]; !ret {
+					return
+				}
 			}
 		}
 	}
 	return
 }
 
+// Partial returns a partial version of the key. The ID fields of the last token
+// will be set to zero/empty.
+func (k *Key) Partial() *Key {

[iannucci, 2016/06/14 01:46:04]

RemoveID? WithoutID?

[dnj (Google), 2016/06/14 04:24:18]

I changed "Incomplete" to "IsIncomplete" (asking question), and this to
"Incomplete".

+	if k.Incomplete() {
+		return k
+	}
+	return NewKey(k.appID, k.namespace, k.Kind(), "", 0, k.Parent())
+}
+
+// WithID returns a key with the same kind as k, but with the specified string

[iannucci, 2016/06/14 01:46:04]

kind here is also confusing for the same reason.

[dnj (Google), 2016/06/14 04:24:18]

Done.

+// and integer ID values.
+func (k *Key) WithID(stringID string, intID int64) *Key {
+	if k.StringID() == stringID && k.IntID() == intID {
+		return k
+	}
+	return NewKey(k.appID, k.namespace, k.Kind(), stringID, intID, k.Parent())
+}
+
 // Split componentizes the key into pieces (AppID, Namespace and tokens)
 //
 // Each token represents one piece of they key's 'path'.