dbus_threads_init_default, dbus_threads_init: be safe to call at any time

On Unix, we use a pthreads mutex, which can be allocated and
initialized in global memory.

On Windows, we use a CRITICAL_SECTION, together with a call to
InitializeCriticalSection() from the constructor of a global static
C++ object (thanks to Ralf Habacker for suggesting this approach).

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=54972
Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Alban Crequy <alban.crequy@collabora.co.uk>
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>

1 files changed, 28 insertions, 0 deletions

diff --git a/dbus/dbus-sysdeps-thread-win.c b/dbus/dbus-sysdeps-thread-win.c
index 4c4442a6..0887a549 100644
--- a/dbus/dbus-sysdeps-thread-win.c
+++ b/dbus/dbus-sysdeps-thread-win.c
@@ -30,6 +30,21 @@
 
 #include <windows.h>
 
+static dbus_bool_t global_init_done = FALSE;
+static CRITICAL_SECTION init_lock;
+
+/* Called from C++ code in dbus-init-win.cpp. */
+void
+_dbus_threads_windows_init_global (void)
+{
+  /* this ensures that the object that acts as our global constructor
+   * actually gets linked in when we're linked statically */
+  _dbus_threads_windows_ensure_ctor_linked ();
+
+  InitializeCriticalSection (&init_lock);
+  global_init_done = TRUE;
+}
+
 struct DBusCondVar {
   DBusList *list;        /**< list thread-local-stored events waiting on the cond variable */
   CRITICAL_SECTION lock; /**< lock protecting the list */
@@ -272,3 +287,16 @@ _dbus_threads_init_platform_specific (void)
   return TRUE;
 }
 
+void
+_dbus_threads_lock_platform_specific (void)
+{
+  _dbus_assert (global_init_done);
+  EnterCriticalSection (&init_lock);
+}
+
+void
+_dbus_threads_unlock_platform_specific (void)
+{
+  _dbus_assert (global_init_done);
+  LeaveCriticalSection (&init_lock);
+}