145 lines
4.7 KiB
Go
145 lines
4.7 KiB
Go
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/*
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*
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* Copyright 2014, Google Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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// Package metadata define the structure of the metadata supported by gRPC library.
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// Please refer to http://www.grpc.io/docs/guides/wire.html for more information about custom-metadata.
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package metadata // import "google.golang.org/grpc/metadata"
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import (
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"fmt"
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"strings"
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"golang.org/x/net/context"
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)
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// DecodeKeyValue returns k, v, nil. It is deprecated and should not be used.
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func DecodeKeyValue(k, v string) (string, string, error) {
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return k, v, nil
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}
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// MD is a mapping from metadata keys to values. Users should use the following
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// two convenience functions New and Pairs to generate MD.
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type MD map[string][]string
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// New creates a MD from given key-value map.
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// Keys are automatically converted to lowercase.
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func New(m map[string]string) MD {
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md := MD{}
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for k, val := range m {
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key := strings.ToLower(k)
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md[key] = append(md[key], val)
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}
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return md
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}
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// Pairs returns an MD formed by the mapping of key, value ...
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// Pairs panics if len(kv) is odd.
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// Keys are automatically converted to lowercase.
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func Pairs(kv ...string) MD {
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if len(kv)%2 == 1 {
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panic(fmt.Sprintf("metadata: Pairs got the odd number of input pairs for metadata: %d", len(kv)))
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}
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md := MD{}
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var key string
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for i, s := range kv {
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if i%2 == 0 {
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key = strings.ToLower(s)
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continue
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}
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md[key] = append(md[key], s)
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}
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return md
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}
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// Len returns the number of items in md.
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func (md MD) Len() int {
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return len(md)
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}
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// Copy returns a copy of md.
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func (md MD) Copy() MD {
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return Join(md)
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}
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// Join joins any number of MDs into a single MD.
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// The order of values for each key is determined by the order in which
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// the MDs containing those values are presented to Join.
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func Join(mds ...MD) MD {
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out := MD{}
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for _, md := range mds {
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for k, v := range md {
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out[k] = append(out[k], v...)
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}
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}
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return out
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}
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type mdIncomingKey struct{}
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type mdOutgoingKey struct{}
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// NewContext is a wrapper for NewOutgoingContext(ctx, md). Deprecated.
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func NewContext(ctx context.Context, md MD) context.Context {
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return NewOutgoingContext(ctx, md)
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}
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// NewIncomingContext creates a new context with incoming md attached.
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func NewIncomingContext(ctx context.Context, md MD) context.Context {
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return context.WithValue(ctx, mdIncomingKey{}, md)
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}
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// NewOutgoingContext creates a new context with outgoing md attached.
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func NewOutgoingContext(ctx context.Context, md MD) context.Context {
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return context.WithValue(ctx, mdOutgoingKey{}, md)
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}
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// FromContext is a wrapper for FromIncomingContext(ctx). Deprecated.
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func FromContext(ctx context.Context) (md MD, ok bool) {
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return FromIncomingContext(ctx)
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}
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// FromIncomingContext returns the incoming MD in ctx if it exists. The
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// returned md should be immutable, writing to it may cause races.
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// Modification should be made to the copies of the returned md.
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func FromIncomingContext(ctx context.Context) (md MD, ok bool) {
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md, ok = ctx.Value(mdIncomingKey{}).(MD)
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return
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}
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// FromOutgoingContext returns the outgoing MD in ctx if it exists. The
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// returned md should be immutable, writing to it may cause races.
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// Modification should be made to the copies of the returned md.
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func FromOutgoingContext(ctx context.Context) (md MD, ok bool) {
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md, ok = ctx.Value(mdOutgoingKey{}).(MD)
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return
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}
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