5fa011dc0c
Fixes the context aware singleflight not preserving context values. full diff: https://github.com/janos/singleflight/compare/v0.3.0...v0.4.0 Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
87 lines
2.9 KiB
Go
87 lines
2.9 KiB
Go
//go:build !go1.21
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// Copyright (c) 2009 The Go Authors. 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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// Source: https://cs.opensource.google/go/go/+/refs/tags/go1.21.1:src/context/context.go
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// The only modifications to the original source were:
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// - renaming WithoutCancel to withoutCancel
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// - replacing the usage of internal reflectlite with reflect
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// - replacing the usage of private value function with Value method call
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package singleflight
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import (
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"context"
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"reflect"
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"time"
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)
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// withoutCancel returns a copy of parent that is not canceled when parent is canceled.
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// The returned context returns no Deadline or Err, and its Done channel is nil.
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// Calling [Cause] on the returned context returns nil.
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func withoutCancel(parent context.Context) context.Context {
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if parent == nil {
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panic("cannot create context from nil parent")
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}
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return withoutCancelCtx{parent}
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}
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type withoutCancelCtx struct {
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c context.Context
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}
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func (withoutCancelCtx) Deadline() (deadline time.Time, ok bool) {
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return
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}
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func (withoutCancelCtx) Done() <-chan struct{} {
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return nil
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}
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func (withoutCancelCtx) Err() error {
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return nil
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}
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func (c withoutCancelCtx) Value(key any) any {
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return c.c.Value(key)
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}
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func (c withoutCancelCtx) String() string {
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return contextName(c.c) + ".WithoutCancel"
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}
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type stringer interface {
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String() string
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}
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func contextName(c context.Context) string {
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if s, ok := c.(stringer); ok {
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return s.String()
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}
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return reflect.TypeOf(c).String()
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}
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