Make ExistsMulti return a BoolList

service/datastore/interface.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 datastore
 
 import (
         "golang.org/x/net/context"
 )
 
+// BoolList is a convenience wrapper for []bool that provides summary methods
+// for working with the list in aggregate.
+type BoolList []bool
+
+// All returns true iff all of the booleans in this list are true.
+func (bl BoolList) All() bool {
+        for _, b := range bl {
+                if !b {
+                        return false
+                }
+        }
+        return true
+}
+
+// Any returns true iff any of the booleans in this list are true.
+func (bl BoolList) Any() bool {
+        for _, b := range bl {
+                if b {
+                        return true
+                }
+        }
+        return false
+}
+
 // Interface is the 'user-friendly' interface to access the current filtered
 // datastore service implementation.
 //
 // Note that in exchange for userfriendliness, this interface ends up doing
 // a lot of reflection.
 //
 // Methods taking 'interface{}' objects describe what a valid type for that
 // interface are in the comments.
 //
 // Struct objects passed in will be converted to PropertyLoadSaver interfaces
@@ skipping 116 matching lines @@
         // Does a Get for this key and returns true iff it exists. Will only return
         // an error if it's not ErrNoSuchEntity. This is slightly more efficient
         // than using Get directly, because it uses the underlying RawInterface to
         // avoid some reflection and copies.
         Exists(k *Key) (bool, error)
 
         // Does a GetMulti for thes keys and returns true iff they exist. Will only
         // return an error if it's not ErrNoSuchEntity. This is slightly more efficient
         // than using Get directly, because it uses the underlying RawInterface to
         // avoid some reflection and copies.
-        ExistsMulti(k []*Key) ([]bool, error)
+        ExistsMulti(k []*Key) (BoolList, error)
 
         // Get retrieves a single object from the datastore
         //
         // dst must be one of:
         //   - *S where S is a struct
         //   - *P where *P is a concrete type implementing PropertyLoadSaver
         Get(dst interface{}) error
 
         // Put inserts a single object into the datastore
         //
@@ skipping 35 matching lines @@
 
         // Testable returns the Testable interface for the implementation, or nil if
         // there is none.
         Testable() Testable
 
         // Raw returns the underlying RawInterface. The Interface and RawInterface may
         // be used interchangably; there's no danger of interleaving access to the
         // datastore via the two.
         Raw() RawInterface
 }