synctest.go

     1  // Copyright 2024 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package synctest provides support for testing concurrent code.
     6  //
     7  // See the testing/synctest package for function documentation.
     8  package synctest
     9  
    10  import (
    11  	_ "unsafe" // for go:linkname
    12  )
    13  
    14  //go:linkname Run
    15  func Run(f func())
    16  
    17  //go:linkname Wait
    18  func Wait()
    19  
    20  //go:linkname acquire
    21  func acquire() any
    22  
    23  //go:linkname release
    24  func release(any)
    25  
    26  //go:linkname inBubble
    27  func inBubble(any, func())
    28  
    29  // A Bubble is a synctest bubble.
    30  //
    31  // Not a public API. Used by syscall/js to propagate bubble membership through syscalls.
    32  type Bubble struct {
    33  	b any
    34  }
    35  
    36  // Acquire returns a reference to the current goroutine's bubble.
    37  // The bubble will not become idle until Release is called.
    38  func Acquire() *Bubble {
    39  	if b := acquire(); b != nil {
    40  		return &Bubble{b}
    41  	}
    42  	return nil
    43  }
    44  
    45  // Release releases the reference to the bubble,
    46  // allowing it to become idle again.
    47  func (b *Bubble) Release() {
    48  	if b == nil {
    49  		return
    50  	}
    51  	release(b.b)
    52  	b.b = nil
    53  }
    54  
    55  // Run executes f in the bubble.
    56  // The current goroutine must not be part of a bubble.
    57  func (b *Bubble) Run(f func()) {
    58  	if b == nil {
    59  		f()
    60  	} else {
    61  		inBubble(b.b, f)
    62  	}
    63  }
    64
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