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

go/src/infra/gae/libs/wrapper/memory/plist.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"
+        "fmt"
+        "reflect"
+        "sort"
+        "time"
+
+        "appengine"
+        "appengine/datastore"
+
+        "github.com/luci/gkvlite"
+        "github.com/luci/luci-go/common/cmpbin"
+)
+
+type typData struct {
+        noIndex bool
+        typ     propValType
+        data    interface{}
+}
+
+func newTypData(noIndex bool, v interface{}) (ret *typData, err error) {
+        typ := pvUNKNOWN
+
+        switch x := v.(type) {
+        case nil:
+                typ = pvNull
+        case time.Time:
+                typ = pvTime
+        case int64:
+                typ = pvInt
+        case float64:
+                typ = pvFloat
+        case bool:
+                if x {
+                        typ = pvBoolTrue
+                } else {
+                        typ = pvBoolFalse
+                }
+        case []byte, datastore.ByteString:
+                typ = pvBytes
+        case appengine.BlobKey:
+                typ = pvBlobKey
+        case string:
+                typ = pvStr
+        case appengine.GeoPoint:
+                typ = pvGeoPoint
+        case *datastore.Key:
+                typ = pvKey
+        }
+        if typ == pvUNKNOWN {
+                err = fmt.Errorf("propValTypeOf: unknown type of %T: %#v", v, v)
+        }
+
+        return &typData{noIndex, typ, v}, err
+}
+
+func (td *typData) WriteBinary(buf *bytes.Buffer, nso nsOption) error {
+        typb := byte(td.typ)
+        if td.noIndex {
+                typb |= 0x80
+        }
+        buf.WriteByte(typb)
+        switch td.typ {
+        case pvNull, pvBoolFalse, pvBoolTrue:
+                return nil
+        case pvInt:
+                cmpbin.WriteInt(buf, td.data.(int64))
+        case pvFloat:
+                writeFloat64(buf, td.data.(float64))
+        case pvStr:
+                writeString(buf, td.data.(string))
+        case pvBytes:
+                if td.noIndex {
+                        writeBytes(buf, td.data.([]byte))
+                } else {
+                        writeBytes(buf, td.data.(datastore.ByteString))
+                }
+        case pvTime:
+                writeTime(buf, td.data.(time.Time))
+        case pvGeoPoint:
+                writeGeoPoint(buf, td.data.(appengine.GeoPoint))
+        case pvKey:
+                writeKey(buf, nso, td.data.(*datastore.Key))
+        case pvBlobKey:
+                writeString(buf, string(td.data.(appengine.BlobKey)))
+        default:
+                return fmt.Errorf("write: unknown type! %v", td)
+        }
+        return nil
+}
+
+func (td *typData) ReadBinary(buf *bytes.Buffer, nso nsOption, ns string) error {
+        typb, err := buf.ReadByte()
+        if err != nil {
+                return err
+        }
+        td.noIndex = (typb & 0x80) != 0 // highbit means noindex
+        td.typ = propValType(typb & 0x7f)
+        switch td.typ {
+        case pvNull:
+                td.data = nil
+        case pvBoolTrue:
+                td.data = true
+        case pvBoolFalse:
+                td.data = false
+        case pvInt:
+                td.data, _, err = cmpbin.ReadInt(buf)
+        case pvFloat:
+                td.data, err = readFloat64(buf)
+        case pvStr:
+                td.data, err = readString(buf)
+        case pvBytes:
+                b := []byte(nil)
+                if b, err = readBytes(buf); err != nil {
+                        return err
+                }
+                if td.noIndex {
+                        td.data = b
+                } else {
+                        td.data = datastore.ByteString(b)
+                }
+        case pvTime:
+                td.data, err = readTime(buf)
+        case pvGeoPoint:
+                td.data, err = readGeoPoint(buf)
+        case pvKey:
+                td.data, err = readKey(buf, nso, ns)
+        case pvBlobKey:
+                s := ""
+                if s, err = readString(buf); err != nil {
+                        return err
+                }
+                td.data = appengine.BlobKey(s)
+        default:
+                return fmt.Errorf("read: unknown type! %v", td)
+        }
+
+        return err
+}
+
+type pvals struct {
+        name string
+        vals []*typData
+}
+
+type propertyList []datastore.Property
+
+var _ = datastore.PropertyLoadSaver((*propertyList)(nil))
+
+func (pl *propertyList) Load(ch <-chan datastore.Property) error {
+        return (*datastore.PropertyList)(pl).Load(ch)
+}
+
+func (pl *propertyList) Save(ch chan<- datastore.Property) error {
+        return (*datastore.PropertyList)(pl).Save(ch)
+}
+
+// collatedProperties is the reduction of a *propertyList such that each entry
+// in a collatedProperties has a unique name. For example, collating this:
+//   pl := &propertyList{
+//     datastore.Property{Name: "wat", Val: "hello"},
+//     datastore.Property{Name: "other", Val: 100},
+//     datastore.Property{Name: "wat", Val: "goodbye", noIndex: true},
+//   }
+//
+// Would get a collatedProperties which looked like:
+//   c := collatedProperties{
+//     &pvals{"wat",   []*typData{&{false, pvStr, "hello"},
+//                                &{true,  pvStr, "goodbye"}}},
+//     &pvals{"other", []*typData{&{false, pvInt, 100}}}
+//   }
+type collatedProperties []*pvals
+
+func (c collatedProperties) defaultIndicies(kind string) []*qIndex {
+        ret := make([]*qIndex, 0, 2*len(c)+1)
+        ret = append(ret, &qIndex{kind, false, nil})
+        for _, pvals := range c {
+                needsIndex := false
+                for _, v := range pvals.vals {
+                        if !v.noIndex {
+                                needsIndex = true
+                                break
+                        }
+                }
+                if !needsIndex {
+                        continue
+                }
+                ret = append(ret, &qIndex{kind, false, []qSortBy{{pvals.name, qASC}}})
+                ret = append(ret, &qIndex{kind, false, []qSortBy{{pvals.name, qDEC}}})
+        }
+        return ret
+}
+
+// serializedPval is a single pvals.vals entry which has been serialized (in
+// qASC order).
+type serializedPval []byte
+
+// serializedPvals is all of the pvals.vals entries from a single pvals (in qASC
+// order). It does not include the pvals.name field.
+type serializedPvals []serializedPval
+
+func (s serializedPvals) Len() int           { return len(s) }
+func (s serializedPvals) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s serializedPvals) Less(i, j int) bool { return bytes.Compare(s[i], s[j]) < 0 }
+
+type mappedPlist map[string]serializedPvals
+
+func (c collatedProperties) indexableMap() (mappedPlist, error) {
+        ret := make(mappedPlist, len(c))
+        for _, pv := range c {
+                data := make(serializedPvals, 0, len(pv.vals))
+                for _, v := range pv.vals {
+                        if v.noIndex {
+                                continue
+                        }
+                        buf := &bytes.Buffer{}
+                        if err := v.WriteBinary(buf, noNS); err != nil {
+                                return nil, err
+                        }
+                        data = append(data, buf.Bytes())
+                }
+                if len(data) == 0 {
+                        continue
+                }
+                sort.Sort(data)
+                ret[pv.name] = data
+        }
+        return ret, nil
+}
+
+// indexRowGen contains enough information to generate all of the index rows which
+// correspond with a propertyList and a qIndex.
+type indexRowGen struct {
+        propVec []serializedPvals
+        orders  []qDirection
+}
+
+// permute calls cb for each index row, in the sorted order of the rows.
+func (s indexRowGen) permute(cb func([]byte)) {
+        iVec := make([]int, len(s.propVec))
+        iVecLim := make([]int, len(s.propVec))
+
+        incPos := func() bool {
+                for i := len(iVec) - 1; i >= 0; i-- {
+                        var done bool
+                        var newVal int
+                        if s.orders[i] == qASC {
+                                newVal = (iVec[i] + 1) % iVecLim[i]
+                                done = newVal != 0
+                        } else {
+                                newVal = (iVec[i] - 1)
+                                if newVal < 0 {
+                                        newVal = iVecLim[i] - 1
+                                } else {
+                                        done = true
+                                }
+                        }
+                        iVec[i] = newVal
+                        if done {
+                                return true
+                        }
+                }
+                return false
+        }
+
+        for i, sps := range s.propVec {
+                iVecLim[i] = len(sps)
+        }
+
+        for i := range iVec {
+                if s.orders[i] == qDEC {
+                        iVec[i] = iVecLim[i] - 1
+                }
+        }
+
+        for {
+                bufsiz := 0
+                for pvalSliceIdx, pvalIdx := range iVec {
+                        bufsiz += len(s.propVec[pvalSliceIdx][pvalIdx])
+                }
+                buf := bytes.NewBuffer(make([]byte, 0, bufsiz))
+                for pvalSliceIdx, pvalIdx := range iVec {
+                        data := s.propVec[pvalSliceIdx][pvalIdx]
+                        if s.orders[pvalSliceIdx] == qASC {
+                                buf.Write(data)
+                        } else {
+                                for _, b := range data {
+                                        buf.WriteByte(b ^ 0xFF)
+                                }
+                        }
+                }
+                cb(buf.Bytes())
+                if !incPos() {
+                        break
+                }
+        }
+}
+
+type matcher struct {
+        buf indexRowGen
+}
+
+// matcher.match checks to see if the mapped, serialized property values
+// match the index. If they do, it returns a indexRowGen. Do not write or modify
+// the data in the indexRowGen.
+func (m *matcher) match(idx *qIndex, mpvals mappedPlist) (indexRowGen, bool) {
+        m.buf.propVec = m.buf.propVec[:0]
+        m.buf.orders = m.buf.orders[:0]
+        for _, sb := range idx.sortby {
+                if pv, ok := mpvals[sb.prop]; ok {
+                        m.buf.propVec = append(m.buf.propVec, pv)
+                        m.buf.orders = append(m.buf.orders, sb.dir)
+                } else {
+                        return indexRowGen{}, false
+                }
+        }
+        return m.buf, true
+}
+
+func (c collatedProperties) indexEntries(k *datastore.Key, idxs []*qIndex) (*memStore, error) {
+        m, err := c.indexableMap()
+        if err != nil {
+                return nil, err
+        }
+
+        ret := newMemStore()
+        idxColl := ret.SetCollection("idx", nil)
+        // getIdxEnts retrieves an index collection or adds it if it's not there.
+        getIdxEnts := func(qi *qIndex) *memCollection {
+                buf := &bytes.Buffer{}
+                qi.WriteBinary(buf)
+                b := buf.Bytes()
+                idxColl.Set(b, []byte{})
+                return ret.SetCollection(fmt.Sprintf("idx:%s:%s", k.Namespace(), b), nil)
+        }
+
+        buf := &bytes.Buffer{}
+        writeKey(buf, noNS, k) // ns is in idxEnts collection name.
+        keyData := buf.Bytes()
+
+        walkPermutations := func(prefix []byte, irg indexRowGen, ents *memCollection) {
+                prev := []byte{} // intentionally make a non-nil slice, gkvlite hates nil.
+                irg.permute(func(data []byte) {
+                        buf := bytes.NewBuffer(make([]byte, 0, len(prefix)+len(data)+len(keyData)))
+                        buf.Write(prefix)
+                        buf.Write(data)
+                        buf.Write(keyData)
+                        ents.Set(buf.Bytes(), prev)
+                        prev = data
+                })
+        }
+
+        mtch := matcher{}
+        for _, idx := range idxs {
+                if irg, ok := mtch.match(idx, m); ok {
+                        idxEnts := getIdxEnts(idx)
+                        if len(irg.propVec) == 0 {
+                                idxEnts.Set(keyData, []byte{}) // propless index, e.g. kind -> key = nil
+                        } else if idx.ancestor {
+                                for ancKey := k; ancKey != nil; ancKey = ancKey.Parent() {
+                                        buf := &bytes.Buffer{}
+                                        writeKey(buf, noNS, ancKey)
+                                        walkPermutations(buf.Bytes(), irg, idxEnts)
+                                }
+                        } else {
+                                walkPermutations(nil, irg, idxEnts)
+                        }
+                }
+        }
+
+        return ret, nil
+}
+
+func (pl *propertyList) indexEntriesWithBuiltins(k *datastore.Key, complexIdxs []*qIndex) (ret *memStore, err error) {
+        c, err := pl.collate()
+        if err == nil {
+                ret, err = c.indexEntries(k, append(c.defaultIndicies(k.Kind()), complexIdxs...))
+        }
+        return
+}
+
+func (pl *propertyList) collate() (collatedProperties, error) {
+        if pl == nil || len(*pl) == 0 {
+                return nil, nil
+        }
+
+        cols := []*pvals{}
+        colIdx := map[string]int{}
+
+        for _, p := range *pl {
+                if idx, ok := colIdx[p.Name]; ok {
+                        c := cols[idx]
+                        td, err := newTypData(p.NoIndex, p.Value)
+                        if err != nil {
+                                return nil, err
+                        }
+                        c.vals = append(c.vals, td)
+                } else {
+                        colIdx[p.Name] = len(cols)
+                        td, err := newTypData(p.NoIndex, p.Value)
+                        if err != nil {
+                                return nil, err
+                        }
+                        cols = append(cols, &pvals{p.Name, []*typData{td}})
+                }
+        }
+
+        return cols, nil
+}
+
+func (pl *propertyList) addCollated(pv *pvals) {
+        for _, v := range pv.vals {
+                *pl = append(*pl, datastore.Property{
+                        Name:     pv.name,
+                        Multiple: len(pv.vals) > 1,
+                        NoIndex:  v.noIndex,
+                        Value:    v.data,
+                })
+        }
+}
+
+func updateIndicies(store *memStore, key *datastore.Key, oldEnt, newEnt *propertyList) error {
+        var err error
+
+        idxColl := store.GetCollection("idx")
+        if idxColl == nil {
+                idxColl = store.SetCollection("idx", nil)
+        }
+
+        // load all current complex query index definitions.
+        compIdx := []*qIndex{}
+        idxColl.VisitItemsAscend(complexQueryPrefix, false, func(i *gkvlite.Item) bool {
+                if !bytes.HasPrefix(i.Key, complexQueryPrefix) {
+                        return false
+                }
+                qi := &qIndex{}
+                if err = qi.ReadBinary(bytes.NewBuffer(i.Key)); err != nil {
+                        return false
+                }
+                compIdx = append(compIdx, qi)
+                return true
+        })
+        if err != nil {
+                return err
+        }
+
+        oldIdx, err := oldEnt.indexEntriesWithBuiltins(key, compIdx)
+        if err != nil {
+                return err
+        }
+
+        newIdx, err := newEnt.indexEntriesWithBuiltins(key, compIdx)
+        if err != nil {
+                return err
+        }
+
+        prefix := "idx:" + key.Namespace() + ":"
+
+        gkvCollide(oldIdx.GetCollection("idx"), newIdx.GetCollection("idx"), func(k, ov, nv []byte) {
+                ks := prefix + string(k)
+                idxColl.Set(k, []byte{})
+
+                coll := store.GetCollection(ks)
+                if coll == nil {
+                        coll = store.SetCollection(ks, nil)
+                }
+                oldColl := oldIdx.GetCollection(ks)
+                newColl := newIdx.GetCollection(ks)
+
+                switch {
+                case ov == nil && nv != nil: // all additions
+                        newColl.VisitItemsAscend(nil, false, func(i *gkvlite.Item) bool {
+                                coll.Set(i.Key, i.Val)
+                                return true
+                        })
+                case ov != nil && nv == nil: // all deletions
+                        oldColl.VisitItemsAscend(nil, false, func(i *gkvlite.Item) bool {
+                                coll.Delete(i.Key)
+                                return true
+                        })
+                case ov != nil && nv != nil: // merge
+                        gkvCollide(oldColl, newColl, func(k, ov, nv []byte) {
+                                if nv == nil {
+                                        coll.Delete(k)
+                                } else {
+                                        coll.Set(k, nv)
+                                }
+                        })
+                default:
+                        panic("impossible")
+                }
+                // TODO(riannucci): remove entries from idxColl and remove index collections
+                // when there are no index entries for that index any more.
+        })
+
+        return nil
+}
+
+func (pl *propertyList) MarshalBinary() ([]byte, error) {
+        cols, err := pl.collate()
+        if err != nil || len(cols) == 0 {
+                return nil, err
+        }
+
+        pieces := make([][]byte, 0, len(*pl)*2+1)
+        for _, pv := range cols {
+                // TODO(riannucci): estimate buffer size better.
+                buf := bytes.NewBuffer(make([]byte, 0, cmpbin.MaxIntLen64+len(pv.name)))
+                writeString(buf, pv.name)
+                err := pv.WriteBinary(buf)
+                if err != nil {
+                        return nil, err
+                }
+                pieces = append(pieces, buf.Bytes())
+        }
+        return bytes.Join(pieces, nil), nil
+}
+
+func (pl *propertyList) UnmarshalBinary(data []byte) error {
+        buf := bytes.NewBuffer(data)
+        for buf.Len() > 0 {
+                name, err := readString(buf)
+                if err != nil {
+                        return err
+                }
+
+                pv := &pvals{name: name}
+                err = pv.ReadBinary(buf)
+                if err != nil {
+                        return err
+                }
+                pl.addCollated(pv)
+        }
+
+        return nil
+}
+
+func toPL(src interface{}) (ret *propertyList, err error) {
+        propchan := make(chan datastore.Property)
+        ret = &propertyList{}
+        go func() { err = datastore.SaveStruct(src, propchan) }()
+        err2 := ret.Load(propchan)
+        if err != nil {
+                return
+        }
+        return ret, err2
+}
+
+func fromPL(props *propertyList, dst interface{}) (err error) {
+        propchan := make(chan datastore.Property)
+        go func() { err = props.Save(propchan) }()
+        err2 := datastore.LoadStruct(dst, propchan)
+        if err != nil {
+                return err
+        }
+        return err2
+}
+
+type propValType byte
+
+var byteSliceType = reflect.TypeOf([]byte(nil))
+
+// These constants are in the order described by
+//   https://cloud.google.com/appengine/docs/go/datastore/entities#Go_Value_type_ordering
+// with a slight divergence for the Int/Time split.
+// NOTE: this enum can only occupy 7 bits, because we use the high bit to encode
+// indexed/non-indexed. See typData.WriteBinary.
+const (
+        pvNull propValType = iota
+        pvInt
+
+        // NOTE: this is a slight divergence; times and integers actually sort
+        // together (apparently?) in datastore. This is probably insane, and I don't
+        // want to add the complexity of field 'meaning' as a sparate concept from the
+        // field's 'type' (which is what datastore seems to do, judging from the
+        // protobufs). So if you're here because you implemented an app which relies
+        // on time.Time and int64 sorting together, then this is why your app acts
+        // differently in production. My advice is to NOT DO THAT. If you really want
+        // this (and you probably don't), you should take care of the time.Time <->
+        // int64 conversion in your app and just use a property type of int64.
+        pvTime
+
+        // NOTE: this is also a slight divergence, but not a semantic one. IIUC, in
+        // datastore 'bool' is actually the type and the value is either 0 or
+        // 1 (taking another byte to store). Since we have plenty of space in this
+        // type byte, I just merge the value into the type for booleans. If this
+        // becomes problematic, consider changing this to just pvBool, and then
+        // encoding a 0 or 1 as a byte in the relevant marshalling routines.
+        pvBoolFalse
+        pvBoolTrue
+        pvBytes // []byte or datastore.ByteString
+        pvStr   // string or string noindex
+        pvFloat
+        pvGeoPoint
+
+        // These two are problematic, because they force us to bind to the appengine
+        // SDK code. If we can drop support for these and turn them into hard errors,
+        // that could let us decouple from the various appengine SDKs. Maybe.
+        pvKey     // TODO(riannucci): remove support for this  (use a string)
+        pvBlobKey // TODO(riannucci): remove support for this  (use a string)
+
+        pvUNKNOWN
+)
+
+func (p *pvals) ReadBinary(buf *bytes.Buffer) error {
+        n, _, err := cmpbin.ReadUint(buf)
+        if err != nil {
+                return err
+        }
+
+        p.vals = make([]*typData, n)
+        for i := range p.vals {
+                p.vals[i] = &typData{}
+                err := p.vals[i].ReadBinary(buf, withNS, "")
+                if err != nil {
+                        return err
+                }
+        }
+
+        return nil
+}
+
+func (p *pvals) WriteBinary(buf *bytes.Buffer) error {
+        cmpbin.WriteUint(buf, uint64(len(p.vals)))
+        for _, v := range p.vals {
+                if err := v.WriteBinary(buf, withNS); err != nil {
+                        return err
+                }
+        }
+        return nil
+}