cubefs

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/*
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 *
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 * Copyright 2020 gRPC authors.
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *     http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 *
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 */
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package grpcutil
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import (
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	"context"
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	"google.golang.org/grpc/metadata"
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)
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type mdExtraKey struct{}
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// WithExtraMetadata creates a new context with incoming md attached.
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func WithExtraMetadata(ctx context.Context, md metadata.MD) context.Context {
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	return context.WithValue(ctx, mdExtraKey{}, md)
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}
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// ExtraMetadata returns the incoming metadata in ctx if it exists.  The
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// returned MD should not be modified. Writing to it may cause races.
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// Modification should be made to copies of the returned MD.
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func ExtraMetadata(ctx context.Context) (md metadata.MD, ok bool) {
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	md, ok = ctx.Value(mdExtraKey{}).(metadata.MD)
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	return
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}
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