Refactor keys and queries in datastore service and implementation.

filter/dscache/plan.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package dscache
 
 import (
         "bytes"
 
         ds "github.com/luci/gae/service/datastore"
         mc "github.com/luci/gae/service/memcache"
         "github.com/luci/luci-go/common/errors"
         "github.com/luci/luci-go/common/logging"
         "golang.org/x/net/context"
 )
 
 type facts struct {
-        getKeys   []ds.Key
+        getKeys   []*ds.Key
         getMeta   ds.MultiMetaGetter
         lockItems []mc.Item
         nonce     []byte
 }
 
 type plan struct {
         keepMeta bool
 
         // idxMap maps from the original list of keys to the reduced set of keys in
         // toGet. E.g. given the index `j` while looping over toGet, idxMap[j] will
         // equal the index in the original facts.getKeys list.
         idxMap []int
 
         // toGet is a list of datstore keys to retrieve in the call down to the
         // underlying datastore. It will have length >= facts.getKeys. All the keys
         // in this will be valid (not nil).
-        toGet []ds.Key
+        toGet []*ds.Key
 
         // toGetMeta is a MultiMetaGetter to be passed in the call down to the
         // underlying datastore.GetMulti. It has the same length as toGet.
         toGetMeta ds.MultiMetaGetter
 
         // toSave is the list of memcache items to save the results from the
         // underlying datastore.GetMulti. It MAY contain nils, which is an indicator
         // that this entry SHOULD NOT be saved to memcache.
         toSave []mc.Item
 
         // decoded is a list of all the decoded property maps. Its length always ==
         // len(facts.getKeys). After the plan is formed, it may contain nils. These
         // nils will be filled in from the underlying datastore.GetMulti call in
         // ds.go.
         decoded []ds.PropertyMap
 
         // lme is a LazyMultiError whose target Size == len(facts.getKeys). The errors
         // will eventually bubble back to the layer above this filter in callbacks.
         lme errors.LazyMultiError
 }
 
 // add adds a new entry to be retrieved from the actual underlying datastore
 // (via GetMulti).
 //
 //   - idx is the index into the original facts.getKeys
 //   - get and m are the pair of values that will be passed to datastore.GetMulti
 //   - save is the memcache item to save the result back to. If it's nil, then
 //     it will not be saved back to memcache.
-func (p *plan) add(idx int, get ds.Key, m ds.MetaGetter, save mc.Item) {
+func (p *plan) add(idx int, get *ds.Key, m ds.MetaGetter, save mc.Item) {
         p.idxMap = append(p.idxMap, idx)
         p.toGet = append(p.toGet, get)
 
         p.toSave = append(p.toSave, save)
 
         if p.keepMeta {
                 p.toGetMeta = append(p.toGetMeta, m)
         }
 }
 
@@ skipping 53 matching lines @@
                                 p.add(i, getKey, m, nil)
                         }
 
                 default:
                         // have some other sort of object, or our AddMulti failed to add this item.
                         p.add(i, getKey, m, nil)
                 }
         }
         return &p
 }