Remove uv_init from uv.h and windows backend

include/uv.h

@@ -81,11 +81,10 @@ typedef struct uv_work_s uv_work_t;
  * All callbacks in libuv are made asynchronously. That is they are never
  * made by the function that takes them as a parameter.
  */
-void uv_init();
 uv_loop_t* uv_loop_new();
-
 void uv_loop_delete(uv_loop_t*);
 
+
 /*
  * Returns the default loop.
  */

src/win/core.c

@@ -33,7 +33,22 @@
 
 /* The only event loop we support right now */
 static uv_loop_t uv_default_loop_;
-static int uv_default_loop_initialized_ = 0;
+
+/* uv_once intialization guards */
+static uv_once_t uv_init_guard_ = UV_ONCE_INIT;
+static uv_once_t uv_default_loop_init_guard_ = UV_ONCE_INIT;
+
+
+static void uv_init(void) {
+  /* Initialize winsock */
+  uv_winsock_init();
+
+  /* Fetch winapi function pointers */
+  uv_winapi_init();
+
+  /* Initialize FS */
+  uv_fs_init();
+}
 
 
 static void uv_loop_init(uv_loop_t* loop) {
@@ -68,25 +83,18 @@ static void uv_loop_init(uv_loop_t* loop) {
 }
 
 
-uv_loop_t* uv_default_loop() {
-  if (!uv_default_loop_initialized_) {
-    uv_loop_init(&uv_default_loop_);
-    uv_default_loop_initialized_ = 1;
-  }
+static void uv_default_loop_init(void) {
+  /* Intialize libuv itself first */
+  uv_once(&uv_init_guard_, uv_init);
 
-  return &uv_default_loop_;
+  /* Initialize the main loop */
+  uv_loop_init(&uv_default_loop_);
 }
 
 
-void uv_init() {
-  /* Initialize winsock */
-  uv_winsock_init();
-
-  /* Fetch winapi function pointers */
-  uv_winapi_init();
-
-  /* Initialize FS */
-  uv_fs_init();
+uv_loop_t* uv_default_loop() {
+  uv_once(&uv_default_loop_init_guard_, uv_default_loop_init);
+  return &uv_default_loop_;
 }
 
 

src/win/internal.h

@@ -279,4 +279,19 @@ void uv_winsock_init();
 int uv_ntstatus_to_winsock_error(NTSTATUS status);
 
 
+/* Threads and synchronization */
+typedef struct uv_once_s {
+  unsigned char ran;
+  /* The actual event handle must be aligned to sizeof(HANDLE), so in */
+  /* practice it might overlap padding a little. */
+  HANDLE event;
+  HANDLE padding;
+} uv_once_t;
+
+#define UV_ONCE_INIT \
+  { 0, NULL, NULL }
+
+void uv_once(uv_once_t* guard, void (*callback)(void));
+
+
 #endif /* UV_WIN_INTERNAL_H_ */

src/win/threads.c

@@ -0,0 +1,81 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <assert.h>
+
+#include "uv.h"
+#include "../uv-common.h"
+#include "internal.h"
+
+
+#ifdef _MSC_VER /* msvc */
+# define NOINLINE __declspec (noinline)
+#else  /* gcc */
+# define NOINLINE __attribute__ ((noinline))
+#endif
+
+
+static NOINLINE void uv__once_inner(uv_once_t* guard,
+    void (*callback)(void)) {
+  DWORD result;
+  HANDLE existing_event, created_event;
+  HANDLE* event_ptr;
+
+  /* Fetch and align event_ptr */
+  event_ptr = (HANDLE*) (((uintptr_t) &guard->event + (sizeof(HANDLE) - 1)) &
+    ~(sizeof(HANDLE) - 1));
+
+  created_event = CreateEvent(NULL, 1, 0, NULL);
+  if (created_event == 0) {
+    /* Could fail in a low-memory situation? */
+    uv_fatal_error(GetLastError(), "CreateEvent");
+  }
+
+  existing_event = InterlockedCompareExchangePointer(event_ptr,
+                                                     created_event,
+                                                     NULL);
+
+  if (existing_event == NULL) {
+    /* We won the race */
+    callback();
+
+    result = SetEvent(created_event);
+    assert(result);
+    guard->ran = 1;
+
+  } else {
+    /* We lost the race. Destroy the event we created and wait for the */
+    /* existing one to become signaled. */
+    CloseHandle(created_event);
+    result = WaitForSingleObject(existing_event, INFINITE);
+    assert(result == WAIT_OBJECT_0);
+  }
+}
+
+
+void uv_once(uv_once_t* guard, void (*callback)(void)) {
+  /* Fast case - avoid WaitForSingleObject. */
+  if (guard->ran) {
+    return;
+  }
+
+  uv__once_inner(guard, callback);
+}

uv.gyp

@@ -114,6 +114,7 @@
             'src/win/stream.c',
             'src/win/tcp.c',
             'src/win/threadpool.c',
+            'src/win/threads.c',
             'src/win/timer.c',
             'src/win/udp.c',
             'src/win/util.c',