33 lines
1.1 KiB
Go
33 lines
1.1 KiB
Go
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// Copyright (C) 2014 Space Monkey, Inc.
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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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package errors
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import (
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"sync/atomic"
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)
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var (
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lastId int32 = 0
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)
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// DataKey's job is to make sure that keys in each error instances namespace
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// are lexically scoped, thus helping developers not step on each others' toes
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// between large packages. You can only store data on an error using a DataKey,
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// and you can only make DataKeys with GenSym().
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type DataKey struct{ id int32 }
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// GenSym generates a brand new, never-before-seen DataKey
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func GenSym() DataKey { return DataKey{id: atomic.AddInt32(&lastId, 1)} }
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