Revert "Refactor current GAE abstraction library to be free of the SDK*"

go/src/infra/gae/libs/wrapper/memory/key.go

+// 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.
+
+package memory
+
+import (
+        "bytes"
+        "errors"
+        "fmt"
+
+        "github.com/golang/protobuf/proto"
+        "github.com/luci/luci-go/common/cmpbin"
+        "github.com/mjibson/goon"
+
+        "appengine"
+        "appengine/datastore"
+        "appengine_internal"
+        basepb "appengine_internal/base"
+)
+
+const keyNumToksReasonableLimit = 50
+
+///////////////////////////// fakeGAECtxForNewKey //////////////////////////////
+
+type fakeGAECtxForNewKey string
+
+var _ = appengine.Context((fakeGAECtxForNewKey)(""))
+
+func (fakeGAECtxForNewKey) Debugf(format string, args ...interface{})    {}
+func (fakeGAECtxForNewKey) Infof(format string, args ...interface{})     {}
+func (fakeGAECtxForNewKey) Warningf(format string, args ...interface{})  {}
+func (fakeGAECtxForNewKey) Errorf(format string, args ...interface{})    {}
+func (fakeGAECtxForNewKey) Criticalf(format string, args ...interface{}) {}
+func (fakeGAECtxForNewKey) Request() interface{}                         { return nil }
+func (f fakeGAECtxForNewKey) Call(service, method string, in, out appengine_internal.ProtoMessage, opts *appengine_internal.CallOptions) error {
+        if service != "__go__" || method != "GetNamespace" {
+                panic(fmt.Errorf("fakeGAECtxForNewKey: cannot facilitate Call(%q, %q, ...)", service, method))
+        }
+        out.(*basepb.StringProto).Value = proto.String(string(f))
+        return nil
+}
+func (fakeGAECtxForNewKey) FullyQualifiedAppID() string { return "dev~my~app" }
+
+/////////////////////////////// Key construction ///////////////////////////////
+
+func newKey(ns, kind, stringID string, intID int64, parent *datastore.Key) *datastore.Key {
+        return datastore.NewKey(fakeGAECtxForNewKey(ns), kind, stringID, intID, parent)
+}
+func newKeyObjError(ns string, knr goon.KindNameResolver, src interface{}) (*datastore.Key, error) {
+        return (&goon.Goon{
+                Context:          fakeGAECtxForNewKey(ns),
+                KindNameResolver: knr}).KeyError(src)
+}
+func newKeyObj(ns string, knr goon.KindNameResolver, obj interface{}) *datastore.Key {
+        k, err := newKeyObjError(ns, knr, obj)
+        if err != nil {
+                panic(err)
+        }
+        return k
+}
+func kind(ns string, knr goon.KindNameResolver, src interface{}) string {
+        return newKeyObj(ns, knr, src).Kind()
+}
+
+/////////////////////////////// Binary Encoding ////////////////////////////////
+
+type keyTok struct {
+        kind     string
+        intID    uint64
+        stringID string
+}
+
+func keyToToks(key *datastore.Key) (namespace string, ret []*keyTok) {
+        var inner func(*datastore.Key)
+        inner = func(k *datastore.Key) {
+                if k.Parent() != nil {
+                        inner(k.Parent())
+                }
+                ret = append(ret, &keyTok{k.Kind(), uint64(k.IntID()), k.StringID()})
+        }
+        inner(key)
+        namespace = key.Namespace()
+        return
+}
+
+func toksToKey(ns string, toks []*keyTok) (ret *datastore.Key) {
+        for _, t := range toks {
+                ret = newKey(ns, t.kind, t.stringID, int64(t.intID), ret)
+        }
+        return
+}
+
+type nsOption bool
+
+const (
+        withNS nsOption = true
+        noNS            = false
+)
+
+func keyBytes(nso nsOption, k *datastore.Key) []byte {
+        buf := &bytes.Buffer{}
+        writeKey(buf, nso, k)
+        return buf.Bytes()
+}
+
+func keyFromByteString(nso nsOption, d string, ns string) (*datastore.Key, error) {
+        return readKey(bytes.NewBufferString(d), nso, ns)
+}
+
+func writeKey(buf *bytes.Buffer, nso nsOption, k *datastore.Key) {
+        // namespace ++ #tokens ++ [tok.kind ++ tok.stringID ++ tok.intID?]*
+        namespace, toks := keyToToks(k)
+        if nso == withNS {
+                writeString(buf, namespace)
+        }
+        cmpbin.WriteUint(buf, uint64(len(toks)))
+        for _, tok := range toks {
+                writeString(buf, tok.kind)
+                writeString(buf, tok.stringID)
+                if tok.stringID == "" {
+                        cmpbin.WriteUint(buf, tok.intID)
+                }
+        }
+}
+
+func readKey(buf *bytes.Buffer, nso nsOption, ns string) (*datastore.Key, error) {
+        namespace := ns
+        if nso == withNS {
+                err := error(nil)
+                if namespace, err = readString(buf); err != nil {
+                        return nil, err
+                }
+        }
+
+        numToks, _, err := cmpbin.ReadUint(buf)
+        if err != nil {
+                return nil, err
+        }
+        if numToks > keyNumToksReasonableLimit {
+                return nil, fmt.Errorf("readKey: tried to decode huge key of length %d", numToks)
+        }
+
+        toks := make([]*keyTok, numToks)
+        for i := uint64(0); i < numToks; i++ {
+                tok := &keyTok{}
+                if tok.kind, err = readString(buf); err != nil {
+                        return nil, err
+                }
+                if tok.stringID, err = readString(buf); err != nil {
+                        return nil, err
+                }
+                if tok.stringID == "" {
+                        if tok.intID, _, err = cmpbin.ReadUint(buf); err != nil {
+                                return nil, err
+                        }
+                        if tok.intID == 0 {
+                                return nil, errors.New("readKey: decoded key with empty stringID and empty intID")
+                        }
+                }
+                toks[i] = tok
+        }
+
+        return toksToKey(namespace, toks), nil
+}
+
+//////////////////////////////// Key utilities /////////////////////////////////
+
+func rootKey(key *datastore.Key) *datastore.Key {
+        for key.Parent() != nil {
+                key = key.Parent()
+        }
+        return key
+}
+
+type keyValidOption bool
+
+const (
+        // userKeyOnly is used with keyValid, and ensures that the key is only one
+        // that's valid for a user program to write to.
+        userKeyOnly keyValidOption = false
+
+        // allowSpecialKeys is used with keyValid, and allows keys for special
+        // metadata objects (like "__entity_group__").
+        allowSpecialKeys = true
+)
+
+// keyValid checks to see if a key is valid by applying a bunch of constraint
+// rules to it (e.g. can't have StringID and IntID set at the same time, can't
+// have a parent key which is Incomplete(), etc.)
+//
+// It verifies that the key is also in the provided namespace. It can also
+// reject keys which are 'special' e.g. have a Kind starting with "__". This
+// behavior is controllable with opt.
+func keyValid(ns string, k *datastore.Key, opt keyValidOption) bool {
+        // copied from the appengine SDK because why would any user program need to
+        // see if a key is valid? /s
+        if k == nil {
+                return false
+        }
+        // since we do "client-side" validation of namespaces, check this here.
+        if k.Namespace() != ns {
+                return false
+        }
+        for ; k != nil; k = k.Parent() {
+                if opt == userKeyOnly && len(k.Kind()) >= 2 && k.Kind()[:2] == "__" { // reserve all Kinds starting with __
+                        return false
+                }
+                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
+}
+
+// keyCouldBeValid is like keyValid, but it allows for the possibility that the
+// last token of the key is Incomplete(). It returns true if the Key will become
+// valid once it recieves an automatically-assigned ID.
+func keyCouldBeValid(ns string, k *datastore.Key, opt keyValidOption) bool {
+        // adds an id to k if it's incomplete.
+        if k.Incomplete() {
+                k = newKey(ns, k.Kind(), "", 1, k.Parent())
+        }
+        return keyValid(ns, k, opt)
+}