impl/memory: Implement Queries

impl/memory/datastore_data.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"
         "sync"
         "sync/atomic"
 
         ds "github.com/luci/gae/service/datastore"
         "github.com/luci/gae/service/datastore/dskey"
         "github.com/luci/gae/service/datastore/serialize"
         "github.com/luci/luci-go/common/errors"
         "golang.org/x/net/context"
 )
 
 //////////////////////////////// dataStoreData /////////////////////////////////
 
 type dataStoreData struct {
         rwlock sync.RWMutex
-        // See README.md for store schema.
-        store *memStore
-        snap  *memStore
+        // See README.md for head schema.
+        head *memStore
+        snap *memStore
 }
 
 var (
         _ = memContextObj((*dataStoreData)(nil))
         _ = sync.Locker((*dataStoreData)(nil))
 )
 
 func newDataStoreData() *dataStoreData {
-        store := newMemStore()
+        head := newMemStore()
         return &dataStoreData{
-                store: store,
-                snap:  store.Snapshot(), // empty but better than a nil pointer.
+                head: head,
+                snap: head.Snapshot(), // empty but better than a nil pointer.
         }
 }
 
 func (d *dataStoreData) Lock() {
         d.rwlock.Lock()
 }
 
 func (d *dataStoreData) Unlock() {
         d.rwlock.Unlock()
 }
 
 func (d *dataStoreData) getQuerySnaps(consistent bool) (idx, head *memStore) {
         d.rwlock.RLock()
         defer d.rwlock.RUnlock()
-        head = d.store.Snapshot()
+        head = d.head.Snapshot()
         if consistent {
                 idx = head
         } else {
                 idx = d.snap
         }
         return
 }
 
 func (d *dataStoreData) takeSnapshot() *memStore {
         d.rwlock.RLock()
         defer d.rwlock.RUnlock()
-        return d.store.Snapshot()
+        return d.head.Snapshot()
 }
 
 func (d *dataStoreData) setSnapshot(snap *memStore) {
         d.rwlock.Lock()
         defer d.rwlock.Unlock()
         d.snap = snap
 }
 
 func (d *dataStoreData) catchupIndexes() {
         d.rwlock.Lock()
         defer d.rwlock.Unlock()
-        d.snap = d.store.Snapshot()
+        d.snap = d.head.Snapshot()
 }
 
 /////////////////////////// indicies(dataStoreData) ////////////////////////////
 
 func groupMetaKey(key ds.Key) []byte {
-        return keyBytes(serialize.WithoutContext,
-                dskey.New("", "", "__entity_group__", "", 1, dskey.Root(key)))
+        return keyBytes(dskey.New("", "", "__entity_group__", "", 1, dskey.Root(key)))
 }
 
 func groupIDsKey(key ds.Key) []byte {
-        return keyBytes(serialize.WithoutContext,
-                dskey.New("", "", "__entity_group_ids__", "", 1, dskey.Root(key)))
+        return keyBytes(dskey.New("", "", "__entity_group_ids__", "", 1, dskey.Root(key)))
 }
 
 func rootIDsKey(kind string) []byte {
-        return keyBytes(serialize.WithoutContext,
-                dskey.New("", "", "__entity_root_ids__", kind, 0, nil))
+        return keyBytes(dskey.New("", "", "__entity_root_ids__", kind, 0, nil))
 }
 
 func curVersion(ents *memCollection, key []byte) int64 {
         if ents != nil {
                 if v := ents.Get(key); v != nil {
                         pm, err := rpm(v)
-                        if err != nil {
-                                panic(err) // memory corruption
-                        }
+                        memoryCorruption(err)
+
                         pl, ok := pm["__version__"]
                         if ok && len(pl) > 0 && pl[0].Type() == ds.PTInt {
                                 return pl[0].Value().(int64)
                         }
-                        panic(fmt.Errorf("__version__ property missing or wrong: %v", pm))
+
+                        memoryCorruption(fmt.Errorf("__version__ property missing or wrong: %v", pm))
                 }
         }
         return 0
 }
 
 func incrementLocked(ents *memCollection, key []byte) int64 {
         ret := curVersion(ents, key) + 1
-        buf := &bytes.Buffer{}
-        serialize.WritePropertyMap(buf, serialize.WithContext, ds.PropertyMap{
-                "__version__": {ds.MkPropertyNI(ret)}})
-        ents.Set(key, buf.Bytes())
+        ents.Set(key, serialize.ToBytes(ds.PropertyMap{
+                "__version__": {ds.MkPropertyNI(ret)},
+        }))
         return ret
 }
 
 func (d *dataStoreData) entsKeyLocked(key ds.Key) (*memCollection, ds.Key) {
         coll := "ents:" + key.Namespace()
-        ents := d.store.GetCollection(coll)
+        ents := d.head.GetCollection(coll)
         if ents == nil {
-                ents = d.store.SetCollection(coll, nil)
+                ents = d.head.SetCollection(coll, nil)
         }
 
         if dskey.Incomplete(key) {
                 idKey := []byte(nil)
                 if key.Parent() == nil {
                         idKey = rootIDsKey(key.Kind())
                 } else {
                         idKey = groupIDsKey(key)
                 }
                 id := incrementLocked(ents, idKey)
                 key = dskey.New(key.AppID(), key.Namespace(), key.Kind(), "", id, key.Parent())
         }
 
         return ents, key
 }
 
 func (d *dataStoreData) putMulti(keys []ds.Key, vals []ds.PropertyMap, cb ds.PutMultiCB) {
         for i, k := range keys {
-                buf := &bytes.Buffer{}
                 pmap, _ := vals[i].Save(false)
-                serialize.WritePropertyMap(buf, serialize.WithoutContext, pmap)
-                dataBytes := buf.Bytes()
+                dataBytes := serialize.ToBytes(pmap)
 
                 k, err := func() (ret ds.Key, err error) {
                         d.rwlock.Lock()
                         defer d.rwlock.Unlock()
 
                         ents, ret := d.entsKeyLocked(k)
                         incrementLocked(ents, groupMetaKey(ret))
 
-                        old := ents.Get(keyBytes(serialize.WithoutContext, ret))
+                        old := ents.Get(keyBytes(ret))
                         oldPM := ds.PropertyMap(nil)
                         if old != nil {
                                 if oldPM, err = rpmWoCtx(old, ret.Namespace()); err != nil {
                                         return
                                 }
                         }
-                        updateIndicies(d.store, ret, oldPM, pmap)
-                        ents.Set(keyBytes(serialize.WithoutContext, ret), dataBytes)
+                        updateIndicies(d.head, ret, oldPM, pmap)
+                        ents.Set(keyBytes(ret), dataBytes)
                         return
                 }()
                 if cb != nil {
                         cb(k, err)
                 }
         }
 }
 
 func getMultiInner(keys []ds.Key, cb ds.GetMultiCB, getColl func() (*memCollection, error)) error {
         ents, err := getColl()
         if err != nil {
                 return err
         }
         if ents == nil {
                 for range keys {
                         cb(nil, ds.ErrNoSuchEntity)
                 }
                 return nil
         }
 
         for _, k := range keys {
-                pdata := ents.Get(keyBytes(serialize.WithoutContext, k))
+                pdata := ents.Get(keyBytes(k))
                 if pdata == nil {
                         cb(nil, ds.ErrNoSuchEntity)
                         continue
                 }
                 cb(rpmWoCtx(pdata, k.Namespace()))
         }
         return nil
 }
 
 func (d *dataStoreData) getMulti(keys []ds.Key, cb ds.GetMultiCB) error {
         getMultiInner(keys, cb, func() (*memCollection, error) {
                 s := d.takeSnapshot()
 
                 return s.GetCollection("ents:" + keys[0].Namespace()), nil
         })
         return nil
 }
 
 func (d *dataStoreData) delMulti(keys []ds.Key, cb ds.DeleteMultiCB) {
         toDel := make([][]byte, 0, len(keys))
         for _, k := range keys {
-                toDel = append(toDel, keyBytes(serialize.WithoutContext, k))
+                toDel = append(toDel, keyBytes(k))
         }
         ns := keys[0].Namespace()
 
         d.rwlock.Lock()
         defer d.rwlock.Unlock()
 
-        ents := d.store.GetCollection("ents:" + ns)
+        ents := d.head.GetCollection("ents:" + ns)
 
         for i, k := range keys {
                 if ents != nil {
                         incrementLocked(ents, groupMetaKey(k))
                         kb := toDel[i]
                         if old := ents.Get(kb); old != nil {
                                 oldPM, err := rpmWoCtx(old, ns)
                                 if err != nil {
                                         if cb != nil {
                                                 cb(err)
                                         }
                                         continue
                                 }
-                                updateIndicies(d.store, k, oldPM, nil)
+                                updateIndicies(d.head, k, oldPM, nil)
                                 ents.Delete(kb)
                         }
                 }
                 if cb != nil {
                         cb(nil)
                 }
         }
 }
 
 func (d *dataStoreData) canApplyTxn(obj memContextObj) bool {
         // TODO(riannucci): implement with Flush/FlushRevert for persistance.
 
         txn := obj.(*txnDataStoreData)
         for rk, muts := range txn.muts {
                 if len(muts) == 0 { // read-only
                         continue
                 }
-                k, err := serialize.ReadKey(bytes.NewBufferString(rk), serialize.WithContext, "", "")
-                if err != nil {
-                        panic(err)
-                }
+                prop, err := serialize.ReadProperty(bytes.NewBufferString(rk), serialize.WithContext, "", "")
+                memoryCorruption(err)
+
+                k := prop.Value().(ds.Key)
 
                 entKey := "ents:" + k.Namespace()
                 mkey := groupMetaKey(k)
-                entsHead := d.store.GetCollection(entKey)
+                entsHead := d.head.GetCollection(entKey)
                 entsSnap := txn.snap.GetCollection(entKey)
                 vHead := curVersion(entsHead, mkey)
                 vSnap := curVersion(entsSnap, mkey)
                 if vHead != vSnap {
                         return false
                 }
         }
         return true
 }
 
 func (d *dataStoreData) applyTxn(c context.Context, obj memContextObj) {
         txn := obj.(*txnDataStoreData)
         for _, muts := range txn.muts {
                 if len(muts) == 0 { // read-only
                         continue
                 }
                 // TODO(riannucci): refactor to do just 1 putMulti, and 1 delMulti
                 for _, m := range muts {
                         err := error(nil)
                         k := m.key
                         if m.data == nil {
                                 d.delMulti([]ds.Key{k},
                                         func(e error) { err = e })
                         } else {
                                 d.putMulti([]ds.Key{m.key}, []ds.PropertyMap{m.data},
                                         func(_ ds.Key, e error) { err = e })
                         }
-                        err = errors.SingleError(err)
-                        if err != nil {
-                                panic(err)
-                        }
+                        impossible(err)
                 }
         }
 }
 
 func (d *dataStoreData) mkTxn(o *ds.TransactionOptions) memContextObj {
         return &txnDataStoreData{
                 // alias to the main datastore's so that testing code can have primitive
                 // access to break features inside of transactions.
                 parent: d,
                 isXG:   o != nil && o.XG,
-                snap:   d.store.Snapshot(),
+                snap:   d.head.Snapshot(),
                 muts:   map[string][]txnMutation{},
         }
 }
 
 func (d *dataStoreData) endTxn() {}
 
 /////////////////////////////// txnDataStoreData ///////////////////////////////
 
 type txnMutation struct {
         key  ds.Key
@@ skipping 22 matching lines @@
 const xgEGLimit = 25
 
 func (*txnDataStoreData) canApplyTxn(memContextObj) bool { return false }
 func (td *txnDataStoreData) endTxn() {
         if atomic.LoadInt32(&td.closed) == 1 {
                 panic("cannot end transaction twice")
         }
         atomic.StoreInt32(&td.closed, 1)
 }
 func (*txnDataStoreData) applyTxn(context.Context, memContextObj) {
-        panic("txnDataStoreData cannot apply transactions")
+        impossible(fmt.Errorf("cannot creat a recursive transaction"))

[dnj (Google), 2015/08/28 17:54:21]

"create"

[iannucci, 2015/08/28 19:48:55]

done

 }
 func (*txnDataStoreData) mkTxn(*ds.TransactionOptions) memContextObj {
-        panic("impossible")
+        impossible(fmt.Errorf("cannot creat a recursive transaction"))

[dnj (Google), 2015/08/28 17:54:21]

"create"

[iannucci, 2015/08/28 19:48:55]

done

+        return nil
 }
 
 func (td *txnDataStoreData) run(f func() error) error {
         // Slightly different from the SDK... datastore and taskqueue each implement
         // this here, where in the SDK only datastore.transaction.Call does.
         if atomic.LoadInt32(&td.closed) == 1 {
                 return errors.New("datastore: transaction context has expired")
         }
         return f()
 }
 
 // writeMutation ensures that this transaction can support the given key/value
 // mutation.
 //
 //   if getOnly is true, don't record the actual mutation data, just ensure that
 //         the key is in an included entity group (or add an empty entry for that
 //         group).
 //
 //   if !getOnly && data == nil, this counts as a deletion instead of a Put.
 //
 // Returns an error if this key causes the transaction to cross too many entity
 // groups.
 func (td *txnDataStoreData) writeMutation(getOnly bool, key ds.Key, data ds.PropertyMap) error {
-        rk := string(keyBytes(serialize.WithContext, dskey.Root(key)))
+        rk := string(keyBytes(dskey.Root(key)))
 
         td.Lock()
         defer td.Unlock()
 
         if _, ok := td.muts[rk]; !ok {
                 limit := 1
                 if td.isXG {
                         limit = xgEGLimit
                 }
                 if len(td.muts)+1 > limit {
@@ skipping 42 matching lines @@
 func (td *txnDataStoreData) delMulti(keys []ds.Key, cb ds.DeleteMultiCB) error {
         for _, k := range keys {
                 err := td.writeMutation(false, k, nil)
                 if cb != nil {
                         cb(err)
                 }
         }
         return nil
 }
 
-func keyBytes(ctx serialize.KeyContext, key ds.Key) []byte {
-        buf := &bytes.Buffer{}
-        serialize.WriteKey(buf, ctx, key)
-        return buf.Bytes()
+func keyBytes(key ds.Key) []byte {
+        return serialize.ToBytes(ds.MkProperty(key))
 }
 
 func rpmWoCtx(data []byte, ns string) (ds.PropertyMap, error) {
         return serialize.ReadPropertyMap(bytes.NewBuffer(data),
                 serialize.WithoutContext, globalAppID, ns)
 }
 
 func rpm(data []byte) (ds.PropertyMap, error) {
         return serialize.ReadPropertyMap(bytes.NewBuffer(data),
                 serialize.WithContext, "", "")
 }
 
 type keyitem interface {
         Key() ds.Key
 }