75 lines
1.6 KiB
C
75 lines
1.6 KiB
C
/* go-note.c -- implement notesleep, notewakeup and noteclear.
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Copyright 2009 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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/* A note is a one-time notification. noteclear clears the note.
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notesleep waits for a call to notewakeup. notewakeup wakes up
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every thread waiting on the note. */
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#include "go-assert.h"
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#include "runtime.h"
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/* We use a single global lock and condition variable. It would be
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better to use a futex on Linux. */
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static pthread_mutex_t note_lock = PTHREAD_MUTEX_INITIALIZER;
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static pthread_cond_t note_cond = PTHREAD_COND_INITIALIZER;
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/* noteclear is called before any calls to notesleep or
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notewakeup. */
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void
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runtime_noteclear (Note* n)
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{
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int32 i;
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i = pthread_mutex_lock (¬e_lock);
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__go_assert (i == 0);
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n->woken = 0;
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i = pthread_mutex_unlock (¬e_lock);
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__go_assert (i == 0);
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}
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/* Wait until notewakeup is called. */
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void
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runtime_notesleep (Note* n)
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{
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int32 i;
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i = pthread_mutex_lock (¬e_lock);
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__go_assert (i == 0);
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while (!n->woken)
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{
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i = pthread_cond_wait (¬e_cond, ¬e_lock);
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__go_assert (i == 0);
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}
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i = pthread_mutex_unlock (¬e_lock);
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__go_assert (i == 0);
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}
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/* Wake up every thread sleeping on the note. */
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void
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runtime_notewakeup (Note *n)
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{
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int32 i;
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i = pthread_mutex_lock (¬e_lock);
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__go_assert (i == 0);
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n->woken = 1;
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i = pthread_cond_broadcast (¬e_cond);
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__go_assert (i == 0);
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i = pthread_mutex_unlock (¬e_lock);
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__go_assert (i == 0);
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}
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