libuv: Restore support for Windows 7

Upstream libuv no longer supports this version.

Utilities/cmlibuv/CMakeLists.txt

@@ -44,7 +44,6 @@ if(WIN32)
     ole32
     psapi
     shell32
-    synchronization
     user32
     userenv
     ws2_32
@@ -54,8 +53,18 @@ if(WIN32)
     )
   list(APPEND uv_defines
     WIN32_LEAN_AND_MEAN
-    _WIN32_WINNT=0x0602
     )
+  if(CMAKE_C_FLAGS MATCHES "(^| )[-/]D *_WIN32_WINNT=([0-9A-Fa-fx]+)( |$)")
+    # The user has explicitly specified a minimum version of Windows.
+    set(_WIN32_WINNT "${CMAKE_MATCH_2}")
+  else()
+    # Support Windows Vista by default.
+    set(_WIN32_WINNT 0x0600)
+    list(APPEND uv_defines _WIN32_WINNT=${_WIN32_WINNT})
+  endif()
+  if(_WIN32_WINNT GREATER_EQUAL 0x0602)
+    list(APPEND uv_libraries synchronization)
+  endif()
   list(APPEND uv_headers
     include/uv/win.h
     include/tree.h

Utilities/cmlibuv/src/win/process.c

@@ -38,6 +38,16 @@
 
 #define SIGKILL         9
 
+static int uv__windows8_or_later(void) {
+  OSVERSIONINFOW os_info;
+  if (!pRtlGetVersion)
+    return 0;
+  os_info.dwOSVersionInfoSize = sizeof(os_info);
+  os_info.szCSDVersion[0] = L'\0';
+  pRtlGetVersion(&os_info);
+  return os_info.dwMajorVersion > 6 ||
+    (os_info.dwMajorVersion == 6 && os_info.dwMinorVersion >= 2);
+}
 
 typedef struct env_var {
   const WCHAR* const wide;
@@ -1062,7 +1072,8 @@ int uv_spawn(uv_loop_t* loop,
    * PROC_THREAD_ATTRIBUTE_HANDLE_LIST ensures only these specific handles are
    * inherited, closing the race condition where concurrent uv_spawn calls
    * could cause handles intended for one child to leak into another. */
-  {
+  /* Windows 8 or above is required to avoid failing on console handles.  */
+  if (uv__windows8_or_later()) {
 #define CHILD_STDIO_COUNT(buffer)                   \
     *((unsigned int*) (buffer))
     int count = CHILD_STDIO_COUNT(child_stdio_buffer);

Utilities/cmlibuv/src/win/winapi.c

@@ -53,6 +53,45 @@ sGetFileInformationByName pGetFileInformationByName;
 
 #if _WIN32_WINNT < 0x0602 /* _WIN32_WINNT_WIN8 */
 sGetSystemTimePreciseAsFileTime pGetSystemTimePreciseAsFileTime;
+sWaitOnAddress pWaitOnAddress;
+sWakeByAddressSingle pWakeByAddressSingle;
+
+static VOID WINAPI uv__WaitOnAddress(volatile VOID* a, PVOID b, SIZE_T sz,
+                                     DWORD timeoutMS)
+{
+  static DWORD const waitMS = 1;
+  DWORD waitedMS = 0;
+  for (;;) {
+    switch (sz) {
+      case 1:
+        if (*(volatile uint8_t*)a != *(uint8_t*)b) return;
+        break;
+      case 2:
+        if (*(volatile uint16_t*)a != *(uint16_t*)b) return;
+        break;
+      case 4:
+        if (*(volatile uint32_t*)a != *(uint32_t*)b) return;
+        break;
+      case 8:
+        if (*(volatile uint64_t*)a != *(uint64_t*)b) return;
+        break;
+      default:
+        return;
+    }
+    if (timeoutMS != INFINITE) {
+      if (waitedMS >= timeoutMS) {
+        return;
+      }
+      waitedMS += waitMS;
+    }
+    Sleep(waitMS);
+  }
+}
+
+static VOID WINAPI uv__WakeByAddressSingle(PVOID address)
+{
+  (void)address;
+}
 #endif
 
 void uv__winapi_init(void) {
@@ -64,6 +103,7 @@ void uv__winapi_init(void) {
   HMODULE api_win_core_file_module;
 #if _WIN32_WINNT < 0x0602 /* _WIN32_WINNT_WIN8 */
   HMODULE kernel32_module;
+  HMODULE api_win_core_synch_module;
 #endif
 
   union {
@@ -84,6 +124,8 @@ void uv__winapi_init(void) {
     sGetFileInformationByName pGetFileInformationByName;
 #if _WIN32_WINNT < 0x0602 /* _WIN32_WINNT_WIN8 */
     sGetSystemTimePreciseAsFileTime pGetSystemTimePreciseAsFileTime;
+    sWaitOnAddress pWaitOnAddress;
+    sWakeByAddressSingle pWakeByAddressSingle;
 #endif
   } u;
 
@@ -191,5 +233,22 @@ void uv__winapi_init(void) {
       pGetSystemTimePreciseAsFileTime = GetSystemTimeAsFileTime;
     }
   }
+
+  api_win_core_synch_module =
+    GetModuleHandleW(L"api-ms-win-core-synch-l1-2-0.dll");
+  if (api_win_core_synch_module != NULL) {
+    u.proc = GetProcAddress(api_win_core_synch_module,
+                            "WaitOnAddress");
+    pWaitOnAddress = u.pWaitOnAddress;
+
+    u.proc = GetProcAddress(api_win_core_synch_module,
+                            "WakeByAddressSingle");
+    pWakeByAddressSingle = u.pWakeByAddressSingle;
+
+  }
+  if (!pWaitOnAddress || !pWakeByAddressSingle) {
+    pWaitOnAddress = uv__WaitOnAddress;
+    pWakeByAddressSingle = uv__WakeByAddressSingle;
+  }
 #endif
 }

Utilities/cmlibuv/src/win/winapi.h

@@ -4848,6 +4848,16 @@ typedef VOID (WINAPI *sGetSystemTimePreciseAsFileTime)
              (LPFILETIME lpSystemTimeAsFileTime);
 extern sGetSystemTimePreciseAsFileTime pGetSystemTimePreciseAsFileTime;
 #define GetSystemTimePreciseAsFileTime pGetSystemTimePreciseAsFileTime
+
+typedef VOID (WINAPI *sWaitOnAddress)
+             (volatile VOID*, PVOID, SIZE_T, DWORD);
+extern sWaitOnAddress pWaitOnAddress;
+#define WaitOnAddress pWaitOnAddress
+
+typedef VOID (WINAPI *sWakeByAddressSingle)
+             (PVOID);
+extern sWakeByAddressSingle pWakeByAddressSingle;
+#define WakeByAddressSingle pWakeByAddressSingle
 #endif
 
 #endif /* UV_WIN_WINAPI_H_ */