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// Copyright 2015 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package datastore
import (
"golang.org/x/net/context"
)
// Transaction is a generic interface used to describe a Datastore transaction.
//
// The nil Transaction represents no transaction context.
//
// TODO: Add some functionality here. Ideas include:
// - Active() bool: is the transaction currently active?
// - AffectedGroups() []*ds.Key: list the groups that have been referenced in
// this Transaction so far.
type Transaction interface{}
// WithoutTransaction returns a Context that isn't bound to a transaction.
// This may be called even when outside of a transaction, in which case the
// input Context is a valid return value.
//
// This can be useful to perform non-transactional tasks given only a Context
// that is bound to a transaction.
func WithoutTransaction(c context.Context) context.Context {
raw := Raw(c)
if t := raw.CurrentTransaction(); t == nil {
// If we're not in a transaction, return the input Contxt.
return c
}
return raw.WithoutTransaction()
}
// CurrentTransaction returns a reference to the current Transaction, or nil
// if the Context does not have a current Transaction.
func CurrentTransaction(c context.Context) Transaction {
return Raw(c).CurrentTransaction()
}