go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/gae/service/datastore/transaction.go

// 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 (
	"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 any

// 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()
}