1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
/*
*
* Copyright 2019 gRPC 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 attributes defines a generic key/value store used in various gRPC
// components.
//
// Experimental
//
// Notice: This package is EXPERIMENTAL and may be changed or removed in a
// later release.
package attributes
import "fmt"
// Attributes is an immutable struct for storing and retrieving generic
// key/value pairs. Keys must be hashable, and users should define their own
// types for keys.
type Attributes struct {
m map[interface{}]interface{}
}
// New returns a new Attributes containing all key/value pairs in kvs. If the
// same key appears multiple times, the last value overwrites all previous
// values for that key. Panics if len(kvs) is not even.
func New(kvs ...interface{}) *Attributes {
if len(kvs)%2 != 0 {
panic(fmt.Sprintf("attributes.New called with unexpected input: len(kvs) = %v", len(kvs)))
}
a := &Attributes{m: make(map[interface{}]interface{}, len(kvs)/2)}
for i := 0; i < len(kvs)/2; i++ {
a.m[kvs[i*2]] = kvs[i*2+1]
}
return a
}
// WithValues returns a new Attributes containing all key/value pairs in a and
// kvs. Panics if len(kvs) is not even. If the same key appears multiple
// times, the last value overwrites all previous values for that key. To
// remove an existing key, use a nil value.
func (a *Attributes) WithValues(kvs ...interface{}) *Attributes {
if a == nil {
return New(kvs...)
}
if len(kvs)%2 != 0 {
panic(fmt.Sprintf("attributes.New called with unexpected input: len(kvs) = %v", len(kvs)))
}
n := &Attributes{m: make(map[interface{}]interface{}, len(a.m)+len(kvs)/2)}
for k, v := range a.m {
n.m[k] = v
}
for i := 0; i < len(kvs)/2; i++ {
n.m[kvs[i*2]] = kvs[i*2+1]
}
return n
}
// Value returns the value associated with these attributes for key, or nil if
// no value is associated with key.
func (a *Attributes) Value(key interface{}) interface{} {
if a == nil {
return nil
}
return a.m[key]
}
|
