Add "MkKeyContext" KeyContext generation function.

impl/memory/datastore_query_execution.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package memory
 
 import (
         "bytes"
         "errors"
         "fmt"
@@ skipping 125 matching lines @@
         }
         return newNormalStrategy(rq.kc, cb, head)
 }
 
 func parseSuffix(aid, ns string, suffixFormat []ds.IndexColumn, suffix []byte, count int) (raw [][]byte, decoded []ds.Property) {
         buf := serialize.Invertible(bytes.NewBuffer(suffix))
         decoded = make([]ds.Property, len(suffixFormat))
         raw = make([][]byte, len(suffixFormat))
 
         err := error(nil)
-        kc := ds.KeyContext{aid, ns}
+        kc := ds.MkKeyContext(aid, ns)
         for i := range decoded {
                 if count >= 0 && i >= count {
                         break
                 }
                 needInvert := suffixFormat[i].Descending
 
                 buf.SetInvert(needInvert)
                 decoded[i], err = serialize.ReadProperty(buf, serialize.WithoutContext, kc)
                 memoryCorruption(err)
 
@@ skipping 136 matching lines @@
                 keyProp := decodedProps[len(decodedProps)-1]
                 if keyProp.Type() != ds.PTKey {
                         impossible(fmt.Errorf("decoded index row doesn't end with a Key: %#v", keyProp))
                 }
 
                 return strategy.handle(
                         rawData, decodedProps, keyProp.Value().(*ds.Key),
                         getCursorFn(suffix))
         })
 }