Split off serialization and key functions to their own packages.

service/datastore/key.go

Index: service/datastore/key.go
diff --git a/service/datastore/key.go b/service/datastore/key.go
deleted file mode 100644
index 0e588754b8af7f2af8fbf6601d28f60d28282282..0000000000000000000000000000000000000000
--- a/service/datastore/key.go
+++ /dev/null
@@ -1,232 +0,0 @@
-// 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.
-
-// adapted from github.com/golang/appengine/datastore
-
-package datastore
-
-import (
-	"bytes"
-	"encoding/base64"
-	"errors"
-	"strconv"
-	"strings"
-
-	pb "github.com/luci/gae/service/datastore/internal/protos/datastore"
-
-	"github.com/golang/protobuf/proto"
-)
-
-// KeyEncode encodes the provided key as a base64-encoded protobuf.
-//
-// This encoding is compatible with the SDK-provided encoding and is agnostic
-// to the underlying implementation of the Key.
-func KeyEncode(k Key) string {
-	n := 0
-	for i := k; i != nil; i = i.Parent() {
-		n++
-	}
-	e := make([]*pb.Path_Element, n)
-	for i := k; i != nil; i = i.Parent() {
-		n--
-		kind := i.Kind()
-		e[n] = &pb.Path_Element{
-			Type: &kind,
-		}
-		// At most one of {Name,Id} should be set.
-		// Neither will be set for incomplete keys.
-		if i.StringID() != "" {
-			sid := i.StringID()
-			e[n].Name = &sid
-		} else if i.IntID() != 0 {
-			iid := i.IntID()
-			e[n].Id = &iid
-		}
-	}
-	var namespace *string
-	if k.Namespace() != "" {
-		namespace = proto.String(k.Namespace())
-	}
-	r, err := proto.Marshal(&pb.Reference{
-		App:       proto.String(k.AppID()),
-		NameSpace: namespace,
-		Path: &pb.Path{
-			Element: e,
-		},
-	})
-	if err != nil {
-		panic(err)
-	}
-
-	// trim padding
-	return strings.TrimRight(base64.URLEncoding.EncodeToString(r), "=")
-}
-
-// KeyToksDecode decodes a base64-encoded protobuf representation of a Key
-// into a tokenized form. This is so that implementations of the gae wrapper
-// can decode to their own implementation of Key.
-//
-// This encoding is compatible with the SDK-provided encoding and is agnostic
-// to the underlying implementation of the Key.
-func KeyToksDecode(encoded string) (appID, namespace string, toks []KeyTok, err error) {
-	// Re-add padding
-	if m := len(encoded) % 4; m != 0 {
-		encoded += strings.Repeat("=", 4-m)
-	}
-	b, err := base64.URLEncoding.DecodeString(encoded)
-	if err != nil {
-		return
-	}
-
-	r := &pb.Reference{}
-	if err = proto.Unmarshal(b, r); err != nil {
-		return
-	}
-
-	appID = r.GetApp()
-	namespace = r.GetNameSpace()
-	toks = make([]KeyTok, len(r.Path.Element))
-	for i, e := range r.Path.Element {
-		toks[i] = KeyTok{
-			Kind:     e.GetType(),
-			IntID:    e.GetId(),
-			StringID: e.GetName(),
-		}
-	}
-	return
-}
-
-// KeyMarshalJSON returns a MarshalJSON-compatible serialization of a Key.
-func KeyMarshalJSON(k Key) ([]byte, error) {
-	return []byte(`"` + KeyEncode(k) + `"`), nil
-}
-
-// KeyUnmarshalJSON returns the tokenized version of a Key as encoded by
-// KeyMarshalJSON.
-func KeyUnmarshalJSON(buf []byte) (appID, namespace string, toks []KeyTok, err error) {
-	if len(buf) < 2 || buf[0] != '"' || buf[len(buf)-1] != '"' {
-		err = errors.New("datastore: bad JSON key")
-	} else {
-		appID, namespace, toks, err = KeyToksDecode(string(buf[1 : len(buf)-1]))
-	}
-	return
-}
-
-// KeyIncomplete returns true iff k doesn't have an id yet.
-func KeyIncomplete(k Key) bool {
-	return k != nil && k.StringID() == "" && k.IntID() == 0
-}
-
-// KeyValid determines if a key is valid, according to a couple rules:
-//   - k is not nil
-//   - every token of k:
-//     - (if !allowSpecial) token's kind doesn't start with '__'
-//     - token's kind and appid are non-blank
-//     - token is not incomplete
-//   - all tokens have the same namespace and appid
-func KeyValid(k Key, allowSpecial bool, aid, ns string) bool {
-	if k == nil {
-		return false
-	}
-	if aid != k.AppID() || ns != k.Namespace() {
-		return false
-	}
-	for ; k != nil; k = k.Parent() {
-		if !allowSpecial && len(k.Kind()) >= 2 && k.Kind()[:2] == "__" {
-			return false
-		}
-		if k.Kind() == "" || k.AppID() == "" {
-			return false
-		}
-		if k.StringID() != "" && k.IntID() != 0 {
-			return false
-		}
-		if k.Parent() != nil {
-			if KeyIncomplete(k.Parent()) {
-				return false
-			}
-			if k.Parent().AppID() != k.AppID() || k.Parent().Namespace() != k.Namespace() {
-				return false
-			}
-		}
-	}
-	return true
-}
-
-// KeyRoot returns the entity root for the given key.
-func KeyRoot(k Key) Key {
-	for k != nil && k.Parent() != nil {
-		k = k.Parent()
-	}
-	return k
-}
-
-// KeysEqual returns true iff the two keys represent identical key values.
-func KeysEqual(a, b Key) (ret bool) {
-	ret = (a.Kind() == b.Kind() &&
-		a.StringID() == b.StringID() &&
-		a.IntID() == b.IntID() &&
-		a.AppID() == b.AppID() &&
-		a.Namespace() == b.Namespace())
-	if !ret {
-		return
-	}
-	ap, bp := a.Parent(), b.Parent()
-	return (ap == nil && bp == nil) || KeysEqual(ap, bp)
-}
-
-func marshalDSKey(b *bytes.Buffer, k Key) {
-	if k.Parent() != nil {
-		marshalDSKey(b, k.Parent())
-	}
-	b.WriteByte('/')
-	b.WriteString(k.Kind())
-	b.WriteByte(',')
-	if k.StringID() != "" {
-		b.WriteString(k.StringID())
-	} else {
-		b.WriteString(strconv.FormatInt(k.IntID(), 10))
-	}
-}
-
-// KeyString returns a human-readable representation of the key, and is the
-// typical implementation of Key.String() (though it isn't guaranteed to be)
-func KeyString(k Key) string {
-	if k == nil {
-		return ""
-	}
-	b := bytes.NewBuffer(make([]byte, 0, 512))
-	marshalDSKey(b, k)
-	return b.String()
-}
-
-// KeySplit splits the key into its constituent parts. Note that if the key is
-// not KeyValid, this method may not provide a round-trip for k.
-func KeySplit(k Key) (appID, namespace string, toks []KeyTok) {
-	if k == nil {
-		return
-	}
-
-	if sk, ok := k.(*GenericKey); ok {
-		if sk == nil {
-			return
-		}
-		return sk.appID, sk.namespace, sk.toks
-	}
-
-	n := 0
-	for i := k; i != nil; i = i.Parent() {
-		n++
-	}
-	toks = make([]KeyTok, n)
-	for i := k; i != nil; i = i.Parent() {
-		n--
-		toks[n].IntID = i.IntID()
-		toks[n].StringID = i.StringID()
-		toks[n].Kind = i.Kind()
-	}
-	appID = k.AppID()
-	namespace = k.Namespace()
-	return
-}