Update deps

vendor/google.golang.org/grpc/attributes/attributes.go

@@ -0,0 +1,130 @@
+/*
+ *
+ * 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"
+	"strings"
+)
+
+// 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.  Values should not be modified after they are added to an
+// Attributes or if they were received from one.  If values implement 'Equal(o
+// interface{}) bool', it will be called by (*Attributes).Equal to determine
+// whether two values with the same key should be considered equal.
+type Attributes struct {
+	m map[interface{}]interface{}
+}
+
+// New returns a new Attributes containing the key/value pair.
+func New(key, value interface{}) *Attributes {
+	return &Attributes{m: map[interface{}]interface{}{key: value}}
+}
+
+// WithValue returns a new Attributes containing the previous keys and values
+// and the new key/value pair.  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.  value should not be modified later.
+func (a *Attributes) WithValue(key, value interface{}) *Attributes {
+	if a == nil {
+		return New(key, value)
+	}
+	n := &Attributes{m: make(map[interface{}]interface{}, len(a.m)+1)}
+	for k, v := range a.m {
+		n.m[k] = v
+	}
+	n.m[key] = value
+	return n
+}
+
+// Value returns the value associated with these attributes for key, or nil if
+// no value is associated with key.  The returned value should not be modified.
+func (a *Attributes) Value(key interface{}) interface{} {
+	if a == nil {
+		return nil
+	}
+	return a.m[key]
+}
+
+// Equal returns whether a and o are equivalent.  If 'Equal(o interface{})
+// bool' is implemented for a value in the attributes, it is called to
+// determine if the value matches the one stored in the other attributes.  If
+// Equal is not implemented, standard equality is used to determine if the two
+// values are equal. Note that some types (e.g. maps) aren't comparable by
+// default, so they must be wrapped in a struct, or in an alias type, with Equal
+// defined.
+func (a *Attributes) Equal(o *Attributes) bool {
+	if a == nil && o == nil {
+		return true
+	}
+	if a == nil || o == nil {
+		return false
+	}
+	if len(a.m) != len(o.m) {
+		return false
+	}
+	for k, v := range a.m {
+		ov, ok := o.m[k]
+		if !ok {
+			// o missing element of a
+			return false
+		}
+		if eq, ok := v.(interface{ Equal(o interface{}) bool }); ok {
+			if !eq.Equal(ov) {
+				return false
+			}
+		} else if v != ov {
+			// Fallback to a standard equality check if Value is unimplemented.
+			return false
+		}
+	}
+	return true
+}
+
+// String prints the attribute map. If any key or values throughout the map
+// implement fmt.Stringer, it calls that method and appends.
+func (a *Attributes) String() string {
+	var sb strings.Builder
+	sb.WriteString("{")
+	first := true
+	for k, v := range a.m {
+		var key, val string
+		if str, ok := k.(interface{ String() string }); ok {
+			key = str.String()
+		}
+		if str, ok := v.(interface{ String() string }); ok {
+			val = str.String()
+		}
+		if !first {
+			sb.WriteString(", ")
+		}
+		sb.WriteString(fmt.Sprintf("%q: %q, ", key, val))
+		first = false
+	}
+	sb.WriteString("}")
+	return sb.String()
+}