1 files changed, 74 insertions, 0 deletions
diff --git a/libgo/runtime/go-note.c b/libgo/runtime/go-note.c
new file mode 100644
index 000000000..3b750f30e
--- /dev/null
+++ b/libgo/runtime/go-note.c
@@ -0,0 +1,74 @@
+/* go-note.c -- implement notesleep, notewakeup and noteclear.
+
+   Copyright 2009 The Go Authors. All rights reserved.
+   Use of this source code is governed by a BSD-style
+   license that can be found in the LICENSE file.  */
+
+/* A note is a one-time notification.  noteclear clears the note.
+   notesleep waits for a call to notewakeup.  notewakeup wakes up
+   every thread waiting on the note.  */
+
+#include "go-assert.h"
+#include "runtime.h"
+
+/* We use a single global lock and condition variable.  It would be
+   better to use a futex on Linux.  */
+
+static pthread_mutex_t note_lock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t note_cond = PTHREAD_COND_INITIALIZER;
+
+/* noteclear is called before any calls to notesleep or
+   notewakeup.  */
+
+void
+noteclear (Note* n)
+{
+  int32 i;
+
+  i = pthread_mutex_lock (&note_lock);
+  __go_assert (i == 0);
+
+  n->woken = 0;
+
+  i = pthread_mutex_unlock (&note_lock);
+  __go_assert (i == 0);
+}
+
+/* Wait until notewakeup is called.  */
+
+void
+notesleep (Note* n)
+{
+  int32 i;
+
+  i = pthread_mutex_lock (&note_lock);
+  __go_assert (i == 0);
+
+  while (!n->woken)
+    {
+      i = pthread_cond_wait (&note_cond, &note_lock);
+      __go_assert (i == 0);
+    }
+
+  i = pthread_mutex_unlock (&note_lock);
+  __go_assert (i == 0);
+}
+
+/* Wake up every thread sleeping on the note.  */
+
+void
+notewakeup (Note *n)
+{
+  int32 i;
+
+  i = pthread_mutex_lock (&note_lock);
+  __go_assert (i == 0);
+
+  n->woken = 1;
+
+  i = pthread_cond_broadcast (&note_cond);
+  __go_assert (i == 0);
+
+  i = pthread_mutex_unlock (&note_lock);
+  __go_assert (i == 0);
+}