v/vlib/sync/waitgroup.v

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// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module sync
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// [init_with=new_waitgroup] // TODO: implement support for init_with struct attribute, and disallow WaitGroup{} from outside the sync.new_waitgroup() function.
[ref_only]
pub struct WaitGroup {
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mut:
mu &Mutex = &Mutex(0)
active int
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}
pub fn new_waitgroup() &WaitGroup {
return &WaitGroup{mu: sync.new_mutex() }
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}
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pub fn (mut wg WaitGroup) add(delta int) {
wg.mu.lock()
wg.active += delta
wg.mu.unlock()
if wg.active < 0 {
panic('Negative number of jobs in waitgroup')
}
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}
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pub fn (mut wg WaitGroup) done() {
wg.add(-1)
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}
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pub fn (wg &WaitGroup) wait() {
for wg.active > 0 {
// Do not remove this, busy empty loops are optimized
// with -prod by some compilers, see issue #2874
$if windows {
C.Sleep(1)
} $else {
C.usleep(1000)
}
}
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}