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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	"strconv"
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	"time"
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)
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const maxTimeoutValue int64 = 100000000 - 1
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// div does integer division and round-up the result. Note that this is
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// equivalent to (d+r-1)/r but has less chance to overflow.
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func div(d, r time.Duration) int64 {
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	if d%r > 0 {
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		return int64(d/r + 1)
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	}
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	return int64(d / r)
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}
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// EncodeDuration encodes the duration to the format grpc-timeout header
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// accepts.
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//
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// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
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func EncodeDuration(t time.Duration) string {
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	// TODO: This is simplistic and not bandwidth efficient. Improve it.
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	if t <= 0 {
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		return "0n"
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	}
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	if d := div(t, time.Nanosecond); d <= maxTimeoutValue {
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		return strconv.FormatInt(d, 10) + "n"
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	}
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	if d := div(t, time.Microsecond); d <= maxTimeoutValue {
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		return strconv.FormatInt(d, 10) + "u"
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	}
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	if d := div(t, time.Millisecond); d <= maxTimeoutValue {
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		return strconv.FormatInt(d, 10) + "m"
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	}
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	if d := div(t, time.Second); d <= maxTimeoutValue {
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		return strconv.FormatInt(d, 10) + "S"
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	}
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	if d := div(t, time.Minute); d <= maxTimeoutValue {
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		return strconv.FormatInt(d, 10) + "M"
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	}
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	// Note that maxTimeoutValue * time.Hour > MaxInt64.
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	return strconv.FormatInt(div(t, time.Hour), 10) + "H"
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}
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