win: make uv_hrtime() thread-safe

joyent · Sep 11, 2011 · c5a489b · c5a489b
1 parent 2c96ad2
commit c5a489b
Showing 1 changed file with 15 additions and 15 deletions.
diff --git a/src/win/timer.c b/src/win/timer.c
@@ -33,7 +33,7 @@
 /* The resolution of the high-resolution clock. */
 static int64_t uv_ticks_per_msec_ = 0;
 static uint64_t uv_hrtime_frequency_ = 0;
-static char uv_hrtime_initialized_ = 0;
+static uv_once_t uv_hrtime_init_guard_ = UV_ONCE_INIT;
 
 
 void uv_update_time(uv_loop_t* loop) {
@@ -57,24 +57,24 @@ int64_t uv_now(uv_loop_t* loop) {
   return loop->time;
 }
 
-/* TODO: thread safety */
-uint64_t uv_hrtime(void) {
-  LARGE_INTEGER counter;
-
-  /* When called for the first time, obtain the high-resolution clock */
-  /* frequency. */
-  if (!uv_hrtime_initialized_) {
-    uv_hrtime_initialized_ = 1;
 
-    if (!QueryPerformanceFrequency(&counter)) {
-      uv_hrtime_frequency_ = 0;
-      /* uv_set_sys_error(loop, GetLastError()); */
-      return 0;
-    }
+static void uv_hrtime_init(void) {
+  LARGE_INTEGER frequency;
 
-    uv_hrtime_frequency_ = counter.QuadPart;
+  if (!QueryPerformanceFrequency(&frequency)) {
+    uv_hrtime_frequency_ = 0;
+    return;
   }
 
+  uv_hrtime_frequency_ = frequency.QuadPart;
+}
+
+
+uint64_t uv_hrtime(void) {
+  LARGE_INTEGER counter;
+
+  uv_once(&uv_hrtime_init_guard_, uv_hrtime_init);
+
   /* If the performance frequency is zero, there's no support. */
   if (!uv_hrtime_frequency_) {
     /* uv_set_sys_error(loop, ERROR_NOT_SUPPORTED); */