/usr/share/gocode/src/google.golang.org/appengine/datastore/key.go is in golang-google-appengine-dev 0.0~git20150606-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 | // Copyright 2011 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package datastore
import (
"bytes"
"encoding/base64"
"encoding/gob"
"errors"
"fmt"
"strconv"
"strings"
"github.com/golang/protobuf/proto"
"golang.org/x/net/context"
"google.golang.org/appengine/internal"
pb "google.golang.org/appengine/internal/datastore"
)
// Key represents the datastore key for a stored entity, and is immutable.
type Key struct {
kind string
stringID string
intID int64
parent *Key
appID string
namespace string
}
// Kind returns the key's kind (also known as entity type).
func (k *Key) Kind() string {
return k.kind
}
// StringID returns the key's string ID (also known as an entity name or key
// name), which may be "".
func (k *Key) StringID() string {
return k.stringID
}
// IntID returns the key's integer ID, which may be 0.
func (k *Key) IntID() int64 {
return k.intID
}
// Parent returns the key's parent key, which may be nil.
func (k *Key) Parent() *Key {
return k.parent
}
// AppID returns the key's application ID.
func (k *Key) AppID() string {
return k.appID
}
// Namespace returns the key's namespace.
func (k *Key) Namespace() string {
return k.namespace
}
// Incomplete returns whether the key does not refer to a stored entity.
// In particular, whether the key has a zero StringID and a zero IntID.
func (k *Key) Incomplete() bool {
return k.stringID == "" && k.intID == 0
}
// valid returns whether the key is valid.
func (k *Key) valid() bool {
if k == nil {
return false
}
for ; k != nil; k = k.parent {
if k.kind == "" || k.appID == "" {
return false
}
if k.stringID != "" && k.intID != 0 {
return false
}
if k.parent != nil {
if k.parent.Incomplete() {
return false
}
if k.parent.appID != k.appID || k.parent.namespace != k.namespace {
return false
}
}
}
return true
}
// Equal returns whether two keys are equal.
func (k *Key) Equal(o *Key) bool {
for k != nil && o != nil {
if k.kind != o.kind || k.stringID != o.stringID || k.intID != o.intID || k.appID != o.appID || k.namespace != o.namespace {
return false
}
k, o = k.parent, o.parent
}
return k == o
}
// root returns the furthest ancestor of a key, which may be itself.
func (k *Key) root() *Key {
for k.parent != nil {
k = k.parent
}
return k
}
// marshal marshals the key's string representation to the buffer.
func (k *Key) marshal(b *bytes.Buffer) {
if k.parent != nil {
k.parent.marshal(b)
}
b.WriteByte('/')
b.WriteString(k.kind)
b.WriteByte(',')
if k.stringID != "" {
b.WriteString(k.stringID)
} else {
b.WriteString(strconv.FormatInt(k.intID, 10))
}
}
// String returns a string representation of the key.
func (k *Key) String() string {
if k == nil {
return ""
}
b := bytes.NewBuffer(make([]byte, 0, 512))
k.marshal(b)
return b.String()
}
type gobKey struct {
Kind string
StringID string
IntID int64
Parent *gobKey
AppID string
Namespace string
}
func keyToGobKey(k *Key) *gobKey {
if k == nil {
return nil
}
return &gobKey{
Kind: k.kind,
StringID: k.stringID,
IntID: k.intID,
Parent: keyToGobKey(k.parent),
AppID: k.appID,
Namespace: k.namespace,
}
}
func gobKeyToKey(gk *gobKey) *Key {
if gk == nil {
return nil
}
return &Key{
kind: gk.Kind,
stringID: gk.StringID,
intID: gk.IntID,
parent: gobKeyToKey(gk.Parent),
appID: gk.AppID,
namespace: gk.Namespace,
}
}
func (k *Key) GobEncode() ([]byte, error) {
buf := new(bytes.Buffer)
if err := gob.NewEncoder(buf).Encode(keyToGobKey(k)); err != nil {
return nil, err
}
return buf.Bytes(), nil
}
func (k *Key) GobDecode(buf []byte) error {
gk := new(gobKey)
if err := gob.NewDecoder(bytes.NewBuffer(buf)).Decode(gk); err != nil {
return err
}
*k = *gobKeyToKey(gk)
return nil
}
func (k *Key) MarshalJSON() ([]byte, error) {
return []byte(`"` + k.Encode() + `"`), nil
}
func (k *Key) UnmarshalJSON(buf []byte) error {
if len(buf) < 2 || buf[0] != '"' || buf[len(buf)-1] != '"' {
return errors.New("datastore: bad JSON key")
}
k2, err := DecodeKey(string(buf[1 : len(buf)-1]))
if err != nil {
return err
}
*k = *k2
return nil
}
// Encode returns an opaque representation of the key
// suitable for use in HTML and URLs.
// This is compatible with the Python and Java runtimes.
func (k *Key) Encode() string {
ref := keyToProto("", k)
b, err := proto.Marshal(ref)
if err != nil {
panic(err)
}
// Trailing padding is stripped.
return strings.TrimRight(base64.URLEncoding.EncodeToString(b), "=")
}
// DecodeKey decodes a key from the opaque representation returned by Encode.
func DecodeKey(encoded string) (*Key, 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 nil, err
}
ref := new(pb.Reference)
if err := proto.Unmarshal(b, ref); err != nil {
return nil, err
}
return protoToKey(ref)
}
// NewIncompleteKey creates a new incomplete key.
// kind cannot be empty.
func NewIncompleteKey(c context.Context, kind string, parent *Key) *Key {
return NewKey(c, kind, "", 0, parent)
}
// NewKey creates a new key.
// kind cannot be empty.
// Either one or both of stringID and intID must be zero. If both are zero,
// the key returned is incomplete.
// parent must either be a complete key or nil.
func NewKey(c context.Context, kind, stringID string, intID int64, parent *Key) *Key {
// If there's a parent key, use its namespace.
// Otherwise, use any namespace attached to the context.
var namespace string
if parent != nil {
namespace = parent.namespace
} else {
namespace = internal.NamespaceFromContext(c)
}
return &Key{
kind: kind,
stringID: stringID,
intID: intID,
parent: parent,
appID: internal.FullyQualifiedAppID(c),
namespace: namespace,
}
}
// AllocateIDs returns a range of n integer IDs with the given kind and parent
// combination. kind cannot be empty; parent may be nil. The IDs in the range
// returned will not be used by the datastore's automatic ID sequence generator
// and may be used with NewKey without conflict.
//
// The range is inclusive at the low end and exclusive at the high end. In
// other words, valid intIDs x satisfy low <= x && x < high.
//
// If no error is returned, low + n == high.
func AllocateIDs(c context.Context, kind string, parent *Key, n int) (low, high int64, err error) {
if kind == "" {
return 0, 0, errors.New("datastore: AllocateIDs given an empty kind")
}
if n < 0 {
return 0, 0, fmt.Errorf("datastore: AllocateIDs given a negative count: %d", n)
}
if n == 0 {
return 0, 0, nil
}
req := &pb.AllocateIdsRequest{
ModelKey: keyToProto("", NewIncompleteKey(c, kind, parent)),
Size: proto.Int64(int64(n)),
}
res := &pb.AllocateIdsResponse{}
if err := internal.Call(c, "datastore_v3", "AllocateIds", req, res); err != nil {
return 0, 0, err
}
// The protobuf is inclusive at both ends. Idiomatic Go (e.g. slices, for loops)
// is inclusive at the low end and exclusive at the high end, so we add 1.
low = res.GetStart()
high = res.GetEnd() + 1
if low+int64(n) != high {
return 0, 0, fmt.Errorf("datastore: internal error: could not allocate %d IDs", n)
}
return low, high, nil
}
|