Add datastore dumper tool.

service/datastore/properties.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 datastore
 
 import (
         "bytes"
         "encoding/base64"
         "errors"
@@ skipping 318 matching lines @@
 
         switch t {
         case typeOfKey:
                 if v.IsNil() {
                         return nil
                 }
         }
         return o
 }
 
+func (p Property) String() string {
+        switch p.propType {
+        case PTString, PTBlobKey:
+                return fmt.Sprintf("%s(%q)", p.propType, p.Value())
+        case PTBytes:
+                return fmt.Sprintf("%s(%#x)", p.propType, p.Value())
+        default:
+                return fmt.Sprintf("%s(%v)", p.propType, p.Value())
+        }
+}
+
 // Value returns the current value held by this property. It's guaranteed to
 // be a valid value type (i.e. `p.SetValue(p.Value(), true)` will never return
 // an error).
 func (p *Property) Value() interface{} {
         switch p.propType {
         case PTBytes:
                 return p.value.(byteSequence).bytes()
         case PTString:
                 return p.value.(byteSequence).string()
         case PTBlobKey:
@@ skipping 633 matching lines @@
                 if string(s) == string(t) {
                         return 0, true
                 }
                 if string(s) < string(t) {
                         return -1, true
                 }
                 return 1, true
         }
         return 0, false
 }