go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/gae/impl/memory/transaction.go (about)

     1  // Copyright 2015 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package memory
    16  
    17  import (
    18  	"context"
    19  	"sync/atomic"
    20  
    21  	"go.chromium.org/luci/common/errors"
    22  
    23  	ds "go.chromium.org/luci/gae/service/datastore"
    24  )
    25  
    26  type transactionImpl struct {
    27  	// boolean 0 or 1, use atomic.*Int32 to access.
    28  	closed int32
    29  }
    30  
    31  func (ti *transactionImpl) close() error {
    32  	if !atomic.CompareAndSwapInt32(&ti.closed, 0, 1) {
    33  		return errors.New("transaction is already closed")
    34  	}
    35  	return nil
    36  }
    37  
    38  func (ti *transactionImpl) valid() error {
    39  	if atomic.LoadInt32(&ti.closed) == 1 {
    40  		return errors.New("transaction has expired")
    41  	}
    42  	return nil
    43  }
    44  
    45  func assertTxnValid(c context.Context) error {
    46  	t := ds.CurrentTransaction(c)
    47  	if t == nil {
    48  		return nil
    49  	}
    50  
    51  	return t.(*transactionImpl).valid()
    52  }