go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/server/auth/internal/mergedctx.go (about)

     1  // Copyright 2020 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 internal
    16  
    17  import (
    18  	"context"
    19  	"time"
    20  )
    21  
    22  // MergedContext is a context that inherits everything from Root, except values
    23  // are additionally inherited from Fallback.
    24  type MergedContext struct {
    25  	Root     context.Context
    26  	Fallback context.Context
    27  }
    28  
    29  var _ context.Context = (*MergedContext)(nil)
    30  
    31  func (mc *MergedContext) Value(key any) any {
    32  	val := mc.Root.Value(key)
    33  	if val == nil {
    34  		val = mc.Fallback.Value(key)
    35  	}
    36  	return val
    37  }
    38  
    39  func (mc *MergedContext) Deadline() (time.Time, bool) { return mc.Root.Deadline() }
    40  func (mc *MergedContext) Done() <-chan struct{}       { return mc.Root.Done() }
    41  func (mc *MergedContext) Err() error                  { return mc.Root.Err() }