c213fd1fd8
There is no need to depend on the old context package now that the minimum Go version is 1.7. The move to "context" eliminates our weird vendoring setup. Some vendored code still uses golang.org/x/net/context and it is now vendored in the normal way. This change triggered new vet checks around context.WithTimeout which didn't fire with golang.org/x/net/context.
73 lines
2.8 KiB
Go
73 lines
2.8 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build go1.7
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package context
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import (
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"context" // standard library's context, as of Go 1.7
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"time"
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)
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var (
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todo = context.TODO()
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background = context.Background()
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)
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// Canceled is the error returned by Context.Err when the context is canceled.
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var Canceled = context.Canceled
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// DeadlineExceeded is the error returned by Context.Err when the context's
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// deadline passes.
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var DeadlineExceeded = context.DeadlineExceeded
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// WithCancel returns a copy of parent with a new Done channel. The returned
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// context's Done channel is closed when the returned cancel function is called
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// or when the parent context's Done channel is closed, whichever happens first.
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//
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// Canceling this context releases resources associated with it, so code should
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// call cancel as soon as the operations running in this Context complete.
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func WithCancel(parent Context) (ctx Context, cancel CancelFunc) {
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ctx, f := context.WithCancel(parent)
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return ctx, CancelFunc(f)
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}
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// WithDeadline returns a copy of the parent context with the deadline adjusted
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// to be no later than d. If the parent's deadline is already earlier than d,
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// WithDeadline(parent, d) is semantically equivalent to parent. The returned
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// context's Done channel is closed when the deadline expires, when the returned
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// cancel function is called, or when the parent context's Done channel is
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// closed, whichever happens first.
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//
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// Canceling this context releases resources associated with it, so code should
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// call cancel as soon as the operations running in this Context complete.
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func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
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ctx, f := context.WithDeadline(parent, deadline)
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return ctx, CancelFunc(f)
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}
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// WithTimeout returns WithDeadline(parent, time.Now().Add(timeout)).
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//
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// Canceling this context releases resources associated with it, so code should
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// call cancel as soon as the operations running in this Context complete:
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//
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// func slowOperationWithTimeout(ctx context.Context) (Result, error) {
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// ctx, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
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// defer cancel() // releases resources if slowOperation completes before timeout elapses
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// return slowOperation(ctx)
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// }
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func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
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return WithDeadline(parent, time.Now().Add(timeout))
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}
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// WithValue returns a copy of parent in which the value associated with key is
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// val.
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//
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// Use context Values only for request-scoped data that transits processes and
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// APIs, not for passing optional parameters to functions.
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func WithValue(parent Context, key interface{}, val interface{}) Context {
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return context.WithValue(parent, key, val)
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}
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