Config options for Windows sub-ms Date provider

config/config-options/DUK_USE_DATE_NOW_WINDOWS.yaml

@@ -5,8 +5,4 @@ tags:
   - date
   - portability
 description: >
-  Use Win32 API calls to get current datetime.  When enabled, appropriate
-  date/time headers must be included.
-
-# FIXME: add an include file metadata entry to cause default #include
-# directives to be emitted?
+  Use Win32 API calls to get current datetime.

config/config-options/DUK_USE_DATE_NOW_WINDOWS_SUBMS.yaml

@@ -0,0 +1,9 @@
+define: DUK_USE_DATE_NOW_WINDOWS_SUBMS
+introduced: 2.2.0
+default: false
+tags:
+  - date
+  - portability
+description: >
+  Like DUK_USE_DATE_NOW_WINDOWS but use GetSystemTimePreciseAsFileTime(),
+  available since Windows 8, for sub-millisecond resolution.

config/config-options/DUK_USE_DATE_TZO_WINDOWS.yaml

@@ -6,7 +6,3 @@ tags:
   - portability
 description: >
   Use Win32 API calls to get local time offset at a certain time.
-  When enabled, appropriate date/time headers must be included.
-
-# FIXME: add an include file metadata entry to cause default #include
-# directives to be emitted?

config/config-options/DUK_USE_DATE_TZO_WINDOWS_NO_DST.yaml

@@ -6,5 +6,4 @@ tags:
   - portability
 description: >
   Use Win32 API calls to get local time offset at a certain time.
-  Does not take into account daylight savings time.  When enabled,
-  appropriate date/time headers must be included.
+  Does not take into account daylight savings time.

config/header-snippets/date_provider.h.in

@@ -16,6 +16,8 @@
 #define DUK_USE_DATE_GET_NOW(ctx)            duk_bi_date_get_now_time((ctx))
 #elif defined(DUK_USE_DATE_NOW_WINDOWS)
 #define DUK_USE_DATE_GET_NOW(ctx)            duk_bi_date_get_now_windows((ctx))
+#elif defined(DUK_USE_DATE_NOW_WINDOWS_SUBMS)
+#define DUK_USE_DATE_GET_NOW(ctx)            duk_bi_date_get_now_windows_subms((ctx))
 #else
 #error no provider for DUK_USE_DATE_GET_NOW()
 #endif

config/platforms/platform_windows.h.in

@@ -1,3 +1,8 @@
+/* Windows version can't obviously be determined at compile time,
+ * but _WIN32_WINNT indicates the minimum version targeted:
+ * - https://msdn.microsoft.com/en-us/library/6sehtctf.aspx
+ */
+
 /* Initial fix: disable secure CRT related warnings when compiling Duktape
  * itself (must be defined before including Windows headers).  Don't define
  * for user code including duktape.h.
@@ -8,12 +13,7 @@
 
 /* Windows 32-bit and 64-bit are currently the same. */
 /* MSVC does not have sys/param.h */
-#define DUK_USE_DATE_NOW_WINDOWS
-#define DUK_USE_DATE_TZO_WINDOWS
-/* Note: PRS and FMT are intentionally left undefined for now.  This means
- * there is no platform specific date parsing/formatting but there is still
- * the ISO 8601 standard format.
- */
+
 #if defined(DUK_COMPILING_DUKTAPE)
 /* Only include when compiling Duktape to avoid polluting application build
  * with a lot of unnecessary defines.
@@ -21,10 +21,28 @@
 #include <windows.h>
 #endif
 
+/* GetSystemTimePreciseAsFileTime() available from Windows 8:
+ * https://msdn.microsoft.com/en-us/library/windows/desktop/hh706895(v=vs.85).aspx
+ */
+#if defined(DUK_USE_DATE_NOW_WINDOWS_SUBMS) || defined(DUK_USE_DATE_NOW_WINDOWS)
+/* User forced provider. */
+#else
+#if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0602)
+#define DUK_USE_DATE_NOW_WINDOWS_SUBMS
+#else
+#define DUK_USE_DATE_NOW_WINDOWS
+#endif
+#endif
+
+#define DUK_USE_DATE_TZO_WINDOWS
+
+/* Note: PRS and FMT are intentionally left undefined for now.  This means
+ * there is no platform specific date parsing/formatting but there is still
+ * the ISO 8601 standard format.
+ */
+
 /* QueryPerformanceCounter() may go backwards in Windows XP, so enable for
  * Vista and later: https://msdn.microsoft.com/en-us/library/windows/desktop/dn553408(v=vs.85).aspx#qpc_support_in_windows_versions
- * Check against _WIN32_WINNT which defines the lowest targeted Windows
- * version (we obviously don't know the runtime version at compile time).
  */
 #if !defined(DUK_USE_GET_MONOTONIC_TIME_WINDOWS_QPC) && \
     defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0600)