1 files changed, 71 insertions, 0 deletions
diff --git a/src/pulsecore/once.h b/src/pulsecore/once.h
new file mode 100644
index 0000000..8cd7894
--- /dev/null
+++ b/src/pulsecore/once.h
@@ -0,0 +1,71 @@
+#ifndef foopulseoncehfoo
+#define foopulseoncehfoo
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2006 Lennart Poettering
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <pulsecore/atomic.h>
+#include <pulsecore/mutex.h>
+
+typedef struct pa_once {
+    pa_static_mutex mutex;
+    pa_atomic_t done;
+} pa_once;
+
+#define PA_ONCE_INIT                                                    \
+    {                                                                   \
+        .mutex = PA_STATIC_MUTEX_INIT,                                  \
+        .done = PA_ATOMIC_INIT(0)                                       \
+    }
+
+/* Not to be called directly, use the macros defined below instead */
+bool pa_once_begin(pa_once *o);
+void pa_once_end(pa_once *o);
+
+#define PA_ONCE_BEGIN                                                   \
+    do {                                                                \
+        static pa_once _once = PA_ONCE_INIT;                            \
+        if (pa_once_begin(&_once)) {{
+
+#define PA_ONCE_END                                                     \
+            }                                                           \
+            pa_once_end(&_once);                                        \
+        }                                                               \
+    } while(0)
+
+/*
+
+  Usage of these macros is like this:
+
+  void foo() {
+
+      PA_ONCE_BEGIN {
+
+          ... stuff to be called just once ...
+
+      } PA_ONCE_END;
+  }
+
+*/
+
+/* Same API but calls a function */
+typedef void (*pa_once_func_t) (void);
+void pa_run_once(pa_once *o, pa_once_func_t f);
+
+#endif