diff options
Diffstat (limited to 'vendor/google.golang.org/appengine/datastore/key.go')
-rw-r--r-- | vendor/google.golang.org/appengine/datastore/key.go | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/vendor/google.golang.org/appengine/datastore/key.go b/vendor/google.golang.org/appengine/datastore/key.go new file mode 100644 index 0000000..ac1f002 --- /dev/null +++ b/vendor/google.golang.org/appengine/datastore/key.go @@ -0,0 +1,309 @@ +// 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 +} |