Make rawdatastore API safer for writing filters.

service/rawdatastore/checkfilter.go

Index: service/rawdatastore/checkfilter.go
diff --git a/service/rawdatastore/checkfilter.go b/service/rawdatastore/checkfilter.go
new file mode 100644
index 0000000000000000000000000000000000000000..002c965f5437ede665dab45770b842d0b19526bf
--- /dev/null
+++ b/service/rawdatastore/checkfilter.go
@@ -0,0 +1,123 @@
+// 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 rawdatastore
+
+import (
+	"fmt"
+
+	"github.com/luci/gae/service/info"
+	"github.com/luci/luci-go/common/errors"
+	"golang.org/x/net/context"
+)
+
+type checkFilter struct {
+	Interface
+
+	aid string
+	ns  string
+}
+
+func (tcf *checkFilter) RunInTransaction(f func(c context.Context) error, opts *TransactionOptions) error {
+	if f == nil {
+		return nil
+	}
+	return tcf.Interface.RunInTransaction(f, opts)
+}
+
+func (tcf *checkFilter) Run(q Query, cb RunCB) error {
+	if q == nil || cb == nil {
+		return nil
+	}
+	return tcf.Interface.Run(q, cb)
+}
+
+func (tcf *checkFilter) GetMulti(keys []Key, cb GetMultiCB) error {
+	if len(keys) == 0 || cb == nil {
+		return nil
+	}
+	lme := errors.LazyMultiError{Size: len(keys)}
+	for i, k := range keys {
+		if KeyIncomplete(k) || !KeyValid(k, true, tcf.aid, tcf.ns) {
+			lme.Assign(i, ErrInvalidKey)
+		}
+	}
+	if me := lme.Get(); me != nil {
+		for _, err := range me.(errors.MultiError) {
+			cb(nil, err)
+		}
+		return nil
+	}
+	return tcf.Interface.GetMulti(keys, cb)
+}
+
+func (tcf *checkFilter) PutMulti(keys []Key, vals []PropertyLoadSaver, cb PutMultiCB) error {
+	if len(keys) != len(vals) {
+		return fmt.Errorf("rawdatastore: GetMulti with mismatched keys/vals lengths (%d/%d)", len(keys), len(vals))
+	}
+	if len(keys) == 0 {
+		return nil
+	}
+	lme := errors.LazyMultiError{Size: len(keys)}
+	for i, k := range keys {
+		if KeyIncomplete(k) {
+			k = NewKey(k.AppID(), k.Namespace(), k.Kind(), "", 1, k.Parent())
+		}
+		if !KeyValid(k, false, tcf.aid, tcf.ns) {
+			lme.Assign(i, ErrInvalidKey)
+			continue
+		}
+		v := vals[i]
+		if v == nil {
+			if !lme.Assign(i, errors.New("rawdatastore: PutMulti got nil vals entry")) {
+				lme.Assign(i, v.Problem())
+			}
+		}
+	}
+	if me := lme.Get(); me != nil {
+		for _, err := range me.(errors.MultiError) {
+			cb(nil, err)
+		}
+		return nil
+	}
+
+	err := error(nil)
+	pmVals := make([]PropertyLoadSaver, len(vals))
+	for i, val := range vals {
+		pmVals[i], err = val.Save(true)
+		lme.Assign(i, err)
+	}
+	if me := lme.Get(); me != nil {
+		for _, err := range me.(errors.MultiError) {
+			cb(nil, err)
+		}
+		return nil
+	}
+
+	return tcf.Interface.PutMulti(keys, pmVals, cb)
+}
+
+func (tcf *checkFilter) DeleteMulti(keys []Key, cb DeleteMultiCB) error {
+	if len(keys) == 0 {
+		return nil
+	}
+	lme := errors.LazyMultiError{Size: len(keys)}
+	for i, k := range keys {
+		if KeyIncomplete(k) || !KeyValid(k, false, tcf.aid, tcf.ns) {
+			lme.Assign(i, ErrInvalidKey)
+		}
+	}
+	if me := lme.Get(); me != nil {
+		for _, err := range me.(errors.MultiError) {
+			cb(err)
+		}
+		return nil
+	}
+	return tcf.Interface.DeleteMulti(keys, cb)
+}
+
+func applyCheckFilter(c context.Context, i Interface) Interface {
+	inf := info.Get(c)
+	return &checkFilter{i, inf.AppID(), inf.GetNamespace()}
+}