impl/memory: Implement Queries

service/datastore/properties.go

Index: service/datastore/properties.go
diff --git a/service/datastore/properties.go b/service/datastore/properties.go
index 63156fe68da97b5f7ddf9f4c4600aa2c53861d49..672fdbabac68d37f90a2c18a84cf70c2cf6291f2 100644
--- a/service/datastore/properties.go
+++ b/service/datastore/properties.go
@@ -112,7 +112,7 @@ type PropertyType byte
 //   https://cloud.google.com/appengine/docs/go/datastore/entities#Go_Value_type_ordering
 // with a slight divergence for the Int/Time split.
 // NOTE: this enum can only occupy 7 bits, because we use the high bit to encode
-// indexed/non-indexed. See typData.WriteBinary.
+// indexed/non-indexed. See serialize.WriteProperty.
 const (
 	PTNull PropertyType = iota
 	PTInt
@@ -146,9 +146,19 @@ const (
 	PTKey
 	PTBlobKey
 
+	// NOTE: THIS MUST BE LAST VALUE FOR THE init() ASSERTION BELOW TO WORK.
 	PTUnknown
 )
 
+func init() {
+	if PTUnknown > 0x7f {
+		panic(
+			"PTUnknown (and therefore PropertyType) exceeds 0x7f. This conflicts " +
+				"with serialize.WriteProperty's use of the high bit to indicate " +
+				"NoIndex.")
+	}
+}
+
 func (t PropertyType) String() string {
 	switch t {
 	case PTNull: