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| 1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 // adapted from github.com/golang/appengine/datastore | |
| 6 | |
| 7 package helper | |
| 8 | |
| 9 import ( | |
| 10 "bytes" | |
| 11 "encoding/base64" | |
| 12 "errors" | |
| 13 "strconv" | |
| 14 "strings" | |
| 15 | |
| 16 "github.com/luci/gae" | |
| 17 pb "github.com/luci/gae/helper/internal/protos/datastore" | |
| 18 | |
| 19 "github.com/golang/protobuf/proto" | |
| 20 ) | |
| 21 | |
| 22 // DSKeyEncode encodes the provided key as a base64-encoded protobuf. | |
| 23 // | |
| 24 // This encoding is compatible with the SDK-provided encoding and is agnostic | |
| 25 // to the underlying implementation of the DSKey. | |
| 26 func DSKeyEncode(k gae.DSKey) string { | |
| 27 n := 0 | |
| 28 for i := k; i != nil; i = i.Parent() { | |
| 29 n++ | |
| 30 } | |
| 31 e := make([]*pb.Path_Element, n) | |
| 32 for i := k; i != nil; i = i.Parent() { | |
| 33 n-- | |
| 34 kind := i.Kind() | |
| 35 e[n] = &pb.Path_Element{ | |
| 36 Type: &kind, | |
| 37 } | |
| 38 // At most one of {Name,Id} should be set. | |
| 39 // Neither will be set for incomplete keys. | |
| 40 if i.StringID() != "" { | |
| 41 sid := i.StringID() | |
| 42 e[n].Name = &sid | |
| 43 } else if i.IntID() != 0 { | |
| 44 iid := i.IntID() | |
| 45 e[n].Id = &iid | |
| 46 } | |
| 47 } | |
| 48 var namespace *string | |
| 49 if k.Namespace() != "" { | |
| 50 namespace = proto.String(k.Namespace()) | |
| 51 } | |
| 52 r, err := proto.Marshal(&pb.Reference{ | |
| 53 App: proto.String(k.AppID()), | |
| 54 NameSpace: namespace, | |
| 55 Path: &pb.Path{ | |
| 56 Element: e, | |
| 57 }, | |
| 58 }) | |
| 59 if err != nil { | |
| 60 panic(err) | |
| 61 } | |
| 62 | |
| 63 // trim padding | |
| 64 return strings.TrimRight(base64.URLEncoding.EncodeToString(r), "=") | |
| 65 } | |
| 66 | |
| 67 // DSKeyToksDecode decodes a base64-encoded protobuf representation of a DSKey | |
| 68 // into a tokenized form. This is so that implementations of the gae wrapper | |
| 69 // can decode to their own implementation of DSKey. | |
| 70 // | |
| 71 // This encoding is compatible with the SDK-provided encoding and is agnostic | |
| 72 // to the underlying implementation of the DSKey. | |
| 73 func DSKeyToksDecode(encoded string) (appID, namespace string, toks []gae.DSKeyT
ok, err error) { | |
| 74 // Re-add padding | |
| 75 if m := len(encoded) % 4; m != 0 { | |
| 76 encoded += strings.Repeat("=", 4-m) | |
| 77 } | |
| 78 b, err := base64.URLEncoding.DecodeString(encoded) | |
| 79 if err != nil { | |
| 80 return | |
| 81 } | |
| 82 | |
| 83 r := &pb.Reference{} | |
| 84 if err = proto.Unmarshal(b, r); err != nil { | |
| 85 return | |
| 86 } | |
| 87 | |
| 88 appID = r.GetApp() | |
| 89 namespace = r.GetNameSpace() | |
| 90 toks = make([]gae.DSKeyTok, len(r.Path.Element)) | |
| 91 for i, e := range r.Path.Element { | |
| 92 toks[i] = gae.DSKeyTok{ | |
| 93 Kind: e.GetType(), | |
| 94 IntID: e.GetId(), | |
| 95 StringID: e.GetName(), | |
| 96 } | |
| 97 } | |
| 98 return | |
| 99 } | |
| 100 | |
| 101 // DSKeyMarshalJSON returns a MarshalJSON-compatible serialization of a DSKey. | |
| 102 func DSKeyMarshalJSON(k gae.DSKey) ([]byte, error) { | |
| 103 return []byte(`"` + DSKeyEncode(k) + `"`), nil | |
| 104 } | |
| 105 | |
| 106 // DSKeyUnmarshalJSON returns the tokenized version of a DSKey as encoded by | |
| 107 // DSKeyMarshalJSON. | |
| 108 func DSKeyUnmarshalJSON(buf []byte) (appID, namespace string, toks []gae.DSKeyTo
k, err error) { | |
| 109 if len(buf) < 2 || buf[0] != '"' || buf[len(buf)-1] != '"' { | |
| 110 err = errors.New("datastore: bad JSON key") | |
| 111 } else { | |
| 112 appID, namespace, toks, err = DSKeyToksDecode(string(buf[1 : len
(buf)-1])) | |
| 113 } | |
| 114 return | |
| 115 } | |
| 116 | |
| 117 // DSKeyIncomplete returns true iff k doesn't have an id yet. | |
| 118 func DSKeyIncomplete(k gae.DSKey) bool { | |
| 119 return k != nil && k.StringID() == "" && k.IntID() == 0 | |
| 120 } | |
| 121 | |
| 122 // DSKeyValid determines if a key is valid, according to a couple rules: | |
| 123 // - k is not nil | |
| 124 // - k's namespace matches ns | |
| 125 // - every token of k: | |
| 126 // - (if !allowSpecial) token's kind doesn't start with '__' | |
| 127 // - token's kind and appid are non-blank | |
| 128 // - token is not incomplete | |
| 129 // - all tokens have the same namespace and appid | |
| 130 func DSKeyValid(k gae.DSKey, ns string, allowSpecial bool) bool { | |
| 131 if k == nil { | |
| 132 return false | |
| 133 } | |
| 134 // since we do "client-side" validation of namespaces in local | |
| 135 // implementations, it's convenient to check this here. | |
| 136 if k.Namespace() != ns { | |
| 137 return false | |
| 138 } | |
| 139 for ; k != nil; k = k.Parent() { | |
| 140 if !allowSpecial && len(k.Kind()) >= 2 && k.Kind()[:2] == "__" { | |
| 141 return false | |
| 142 } | |
| 143 if k.Kind() == "" || k.AppID() == "" { | |
| 144 return false | |
| 145 } | |
| 146 if k.StringID() != "" && k.IntID() != 0 { | |
| 147 return false | |
| 148 } | |
| 149 if k.Parent() != nil { | |
| 150 if DSKeyIncomplete(k.Parent()) { | |
| 151 return false | |
| 152 } | |
| 153 if k.Parent().AppID() != k.AppID() || k.Parent().Namespa
ce() != k.Namespace() { | |
| 154 return false | |
| 155 } | |
| 156 } | |
| 157 } | |
| 158 return true | |
| 159 } | |
| 160 | |
| 161 // DSKeyRoot returns the entity root for the given key. | |
| 162 func DSKeyRoot(k gae.DSKey) gae.DSKey { | |
| 163 for k != nil && k.Parent() != nil { | |
| 164 k = k.Parent() | |
| 165 } | |
| 166 return k | |
| 167 } | |
| 168 | |
| 169 // DSKeysEqual returns true iff the two keys represent identical key values. | |
| 170 func DSKeysEqual(a, b gae.DSKey) (ret bool) { | |
| 171 ret = (a.Kind() == b.Kind() && | |
| 172 a.StringID() == b.StringID() && | |
| 173 a.IntID() == b.IntID() && | |
| 174 a.AppID() == b.AppID() && | |
| 175 a.Namespace() == b.Namespace()) | |
| 176 if !ret { | |
| 177 return | |
| 178 } | |
| 179 ap, bp := a.Parent(), b.Parent() | |
| 180 return (ap == nil && bp == nil) || DSKeysEqual(ap, bp) | |
| 181 } | |
| 182 | |
| 183 func marshalDSKey(b *bytes.Buffer, k gae.DSKey) { | |
| 184 if k.Parent() != nil { | |
| 185 marshalDSKey(b, k.Parent()) | |
| 186 } | |
| 187 b.WriteByte('/') | |
| 188 b.WriteString(k.Kind()) | |
| 189 b.WriteByte(',') | |
| 190 if k.StringID() != "" { | |
| 191 b.WriteString(k.StringID()) | |
| 192 } else { | |
| 193 b.WriteString(strconv.FormatInt(k.IntID(), 10)) | |
| 194 } | |
| 195 } | |
| 196 | |
| 197 // DSKeyString returns a human-readable representation of the key, and is the | |
| 198 // typical implementation of DSKey.String() (though it isn't guaranteed to be) | |
| 199 func DSKeyString(k gae.DSKey) string { | |
| 200 if k == nil { | |
| 201 return "" | |
| 202 } | |
| 203 b := bytes.NewBuffer(make([]byte, 0, 512)) | |
| 204 marshalDSKey(b, k) | |
| 205 return b.String() | |
| 206 } | |
| 207 | |
| 208 // DSKeySplit splits the key into its constituent parts. Note that if the key is | |
| 209 // not DSKeyValid, this method may not provide a round-trip for k. | |
| 210 func DSKeySplit(k gae.DSKey) (appID, namespace string, toks []gae.DSKeyTok) { | |
| 211 if k == nil { | |
| 212 return | |
| 213 } | |
| 214 | |
| 215 if sk, ok := k.(*GenericDSKey); ok { | |
| 216 if sk == nil { | |
| 217 return | |
| 218 } | |
| 219 return sk.appID, sk.namespace, sk.toks | |
| 220 } | |
| 221 | |
| 222 n := 0 | |
| 223 for i := k; i != nil; i = i.Parent() { | |
| 224 n++ | |
| 225 } | |
| 226 toks = make([]gae.DSKeyTok, n) | |
| 227 for i := k; i != nil; i = i.Parent() { | |
| 228 n-- | |
| 229 toks[n].IntID = i.IntID() | |
| 230 toks[n].StringID = i.StringID() | |
| 231 toks[n].Kind = i.Kind() | |
| 232 } | |
| 233 appID = k.AppID() | |
| 234 namespace = k.Namespace() | |
| 235 return | |
| 236 } | |
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