SkPDF: SkPDFFont class changes

src/core/SkEnumOperators.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SkEnumOperators_DEFINED
+#define SkEnumOperators_DEFINED

[bungeman-skia, 2016/08/15 21:41:36]

I don't think these are generally desirable enum operators, they're only wanted
for enums that are flags. Maybe SkBitmaskEnum.h or something (it would be nice
for the file and trait to have similar names).

[hal.canary, 2016/08/16 01:27:38]

Done.

+
+#include "SkTLogic.h"
+
+namespace skstd {
+template <typename T> struct is_bitmask_enum : std::false_type {};
+}
+
+template <typename E>
+SK_WHEN(skstd::is_bitmask_enum<E>::value, E) operator|(E l, E r) {

[bungeman-skia, 2016/08/15 21:41:36]

nit: I personally prefer lines 16 and 17 here on one line since they fit.

[hal.canary, 2016/08/16 01:27:38]

Done.

+    using U = skstd::underlying_type_t<E>;
+    return static_cast<E>(static_cast<U>(l) | static_cast<U>(r));
+}
+
+template <typename E>
+SK_WHEN(skstd::is_bitmask_enum<E>::value, E&) operator|=(E& l, E r) {
+    return l = l | r;
+}
+
+template <typename E>
+SK_WHEN(skstd::is_bitmask_enum<E>::value, E) operator&(E l, E r) {
+    using U = skstd::underlying_type_t<E>;
+    return static_cast<E>(static_cast<U>(l) & static_cast<U>(r));
+}
+
+template <typename E>
+SK_WHEN(skstd::is_bitmask_enum<E>::value, E&) operator&=(E& l, E r) {
+    return l = l & r;
+}
+
+#endif  // SkEnumOperators_DEFINED