Bug 1297306 - part4:rename IsEnumFittingWithin with EnumTypeFitsWithin and move it to mfbt/EnumTypeTraits.h. r=froydnj
authorJeremy Chen <jeremychen@mozilla.com>
Wed, 07 Sep 2016 10:20:16 +0800
changeset 312981 4088eddbb3397c248e50e9e8fba2a6faa0d85d5e
parent 312980 cd5cf15a6fa9012624514996352e4f60f9b6be9e
child 312982 b122c6cd236aebf834e61c9f713da142c2e01972
push id30668
push userkwierso@gmail.com
push dateThu, 08 Sep 2016 00:26:51 +0000
treeherdermozilla-central@7c655e03eef7 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersfroydnj
bugs1297306
milestone51.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 1297306 - part4:rename IsEnumFittingWithin with EnumTypeFitsWithin and move it to mfbt/EnumTypeTraits.h. r=froydnj With this change, we could share this EnumTypeTraits between files easily. MozReview-Commit-ID: 9Q2augati7l
layout/style/StyleAnimationValue.h
layout/style/nsCSSProps.h
layout/style/nsCSSValue.h
mfbt/EnumTypeTraits.h
mfbt/moz.build
mfbt/tests/TestEnumTypeTraits.cpp
mfbt/tests/moz.build
testing/cppunittest.ini
--- a/layout/style/StyleAnimationValue.h
+++ b/layout/style/StyleAnimationValue.h
@@ -444,17 +444,17 @@ public:
   void SetNormalValue();
   void SetAutoValue();
   void SetNoneValue();
   void SetIntValue(int32_t aInt, Unit aUnit);
   template<typename T,
            typename = typename std::enable_if<std::is_enum<T>::value>::type>
   void SetIntValue(T aInt, Unit aUnit)
   {
-    static_assert(mozilla::IsEnumFittingWithin<T, int32_t>::value,
+    static_assert(mozilla::EnumTypeFitsWithin<T, int32_t>::value,
                   "aValue must be an enum that fits within mValue.mInt");
     SetIntValue(static_cast<int32_t>(aInt), aUnit);
   }
   void SetCoordValue(nscoord aCoord);
   void SetPercentValue(float aPercent);
   void SetFloatValue(float aFloat);
   void SetColorValue(nscolor aColor);
   void SetCurrentColorValue();
--- a/layout/style/nsCSSProps.h
+++ b/layout/style/nsCSSProps.h
@@ -14,16 +14,17 @@
 #include <limits>
 #include <type_traits>
 #include "nsString.h"
 #include "nsCSSPropertyID.h"
 #include "nsStyleStructFwd.h"
 #include "nsCSSKeywords.h"
 #include "mozilla/CSSEnabledState.h"
 #include "mozilla/UseCounter.h"
+#include "mozilla/EnumTypeTraits.h"
 
 // Length of the "--" prefix on custom names (such as custom property names,
 // and, in the future, custom media query names).
 #define CSS_CUSTOM_NAME_PREFIX_LENGTH 2
 
 // Flags for ParseVariant method
 #define VARIANT_KEYWORD         0x000001  // K
 #define VARIANT_LENGTH          0x000002  // L
@@ -322,34 +323,16 @@ enum nsStyleAnimType {
 
   // discrete values
   eStyleAnimType_Discrete,
 
   // property not animatable
   eStyleAnimType_None
 };
 
-namespace mozilla {
-
-// Type trait that determines whether the integral or enum type Type can fit
-// within the integral type Storage without loss.
-template<typename T, typename Storage>
-struct IsEnumFittingWithin
-  : IntegralConstant<
-      bool,
-      std::is_integral<Storage>::value &&
-      std::numeric_limits<typename std::underlying_type<T>::type>::min() >=
-        std::numeric_limits<Storage>::min() &&
-      std::numeric_limits<typename std::underlying_type<T>::type>::max() <=
-        std::numeric_limits<Storage>::max()
-    >
-{};
-
-} // namespace mozilla
-
 class nsCSSProps {
 public:
   typedef mozilla::CSSEnabledState EnabledState;
 
   struct KTableEntry
   {
     // KTableEntry objects can be initialized either with an int16_t value
     // or a value of an enumeration type that can fit within an int16_t.
@@ -361,17 +344,17 @@ public:
     }
 
     template<typename T,
              typename = typename std::enable_if<std::is_enum<T>::value>::type>
     KTableEntry(nsCSSKeyword aKeyword, T aValue)
       : mKeyword(aKeyword)
       , mValue(static_cast<int16_t>(aValue))
     {
-      static_assert(mozilla::IsEnumFittingWithin<T, int16_t>::value,
+      static_assert(mozilla::EnumTypeFitsWithin<T, int16_t>::value,
                     "aValue must be an enum that fits within mValue");
     }
 
     nsCSSKeyword mKeyword;
     int16_t mValue;
   };
 
   static void AddRefTable(void);
@@ -447,29 +430,29 @@ public:
   // Return |eCSSKeyword_UNKNOWN| if not found.
   static nsCSSKeyword ValueToKeywordEnum(int32_t aValue,
                                          const KTableEntry aTable[]);
   template<typename T,
            typename = typename std::enable_if<std::is_enum<T>::value>::type>
   static nsCSSKeyword ValueToKeywordEnum(T aValue,
                                          const KTableEntry aTable[])
   {
-    static_assert(mozilla::IsEnumFittingWithin<T, int16_t>::value,
+    static_assert(mozilla::EnumTypeFitsWithin<T, int16_t>::value,
                   "aValue must be an enum that fits within KTableEntry::mValue");
     return ValueToKeywordEnum(static_cast<int16_t>(aValue), aTable);
   }
   // Ditto but as a string, return "" when not found.
   static const nsAFlatCString& ValueToKeyword(int32_t aValue,
                                               const KTableEntry aTable[]);
   template<typename T,
            typename = typename std::enable_if<std::is_enum<T>::value>::type>
   static const nsAFlatCString& ValueToKeyword(T aValue,
                                               const KTableEntry aTable[])
   {
-    static_assert(mozilla::IsEnumFittingWithin<T, int16_t>::value,
+    static_assert(mozilla::EnumTypeFitsWithin<T, int16_t>::value,
                   "aValue must be an enum that fits within KTableEntry::mValue");
     return ValueToKeyword(static_cast<int16_t>(aValue), aTable);
   }
 
   static const nsStyleStructID kSIDTable[eCSSProperty_COUNT_no_shorthands];
   static const KTableEntry* const kKeywordTableTable[eCSSProperty_COUNT_no_shorthands];
   static const nsStyleAnimType kAnimTypeTable[eCSSProperty_COUNT_no_shorthands];
   static const ptrdiff_t
--- a/layout/style/nsCSSValue.h
+++ b/layout/style/nsCSSValue.h
@@ -753,17 +753,17 @@ private:
   void DoReset();
 
 public:
   void SetIntValue(int32_t aValue, nsCSSUnit aUnit);
   template<typename T,
            typename = typename std::enable_if<std::is_enum<T>::value>::type>
   void SetIntValue(T aValue, nsCSSUnit aUnit)
   {
-    static_assert(mozilla::IsEnumFittingWithin<T, int32_t>::value,
+    static_assert(mozilla::EnumTypeFitsWithin<T, int32_t>::value,
                   "aValue must be an enum that fits within mValue.mInt");
     SetIntValue(static_cast<int32_t>(aValue), aUnit);
   }
   void SetPercentValue(float aValue);
   void SetFloatValue(float aValue, nsCSSUnit aUnit);
   void SetStringValue(const nsString& aValue, nsCSSUnit aUnit);
   void SetColorValue(nscolor aValue);
   void SetIntegerColorValue(nscolor aValue, nsCSSUnit aUnit);
new file mode 100644
--- /dev/null
+++ b/mfbt/EnumTypeTraits.h
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Type traits for enums. */
+
+#ifndef mozilla_EnumTypeTraits_h
+#define mozilla_EnumTypeTraits_h
+
+#include <type_traits>
+
+namespace mozilla {
+
+namespace detail {
+
+template<size_t EnumSize, bool EnumSigned, size_t StorageSize, bool StorageSigned>
+struct EnumFitsWithinHelper;
+
+// Signed enum, signed storage.
+template<size_t EnumSize, size_t StorageSize>
+struct EnumFitsWithinHelper<EnumSize, true, StorageSize, true>
+  : public std::integral_constant<bool, (EnumSize <= StorageSize)>
+{};
+
+// Signed enum, unsigned storage.
+template<size_t EnumSize, size_t StorageSize>
+struct EnumFitsWithinHelper<EnumSize, true, StorageSize, false>
+  : public std::integral_constant<bool, false>
+{};
+
+// Unsigned enum, signed storage.
+template<size_t EnumSize, size_t StorageSize>
+struct EnumFitsWithinHelper<EnumSize, false, StorageSize, true>
+  : public std::integral_constant<bool, (EnumSize * 2 <= StorageSize)>
+{};
+
+// Unsigned enum, unsigned storage.
+template<size_t EnumSize, size_t StorageSize>
+struct EnumFitsWithinHelper<EnumSize, false, StorageSize, false>
+  : public std::integral_constant<bool, (EnumSize <= StorageSize)>
+{};
+
+} // namespace detail
+
+/*
+ * Type trait that determines whether the enum type T can fit within the
+ * integral type Storage without data loss. This trait should be used with
+ * caution with an enum type whose underlying type has not been explicitly
+ * specified: for such enums, the C++ implementation is free to choose a type
+ * no smaller than int whose range encompasses all possible values of the enum.
+ * So for an enum with only small non-negative values, the underlying type may
+ * be either int or unsigned int, depending on the whims of the implementation.
+ */
+template<typename T, typename Storage>
+struct EnumTypeFitsWithin
+  : public detail::EnumFitsWithinHelper<
+      sizeof(T),
+      std::is_signed<typename std::underlying_type<T>::type>::value,
+      sizeof(Storage),
+      std::is_signed<Storage>::value
+    >
+{
+  static_assert(std::is_enum<T>::value, "must provide an enum type");
+  static_assert(std::is_integral<Storage>::value, "must provide an integral type");
+};
+
+} // namespace mozilla
+
+#endif /* mozilla_EnumTypeTraits_h */
--- a/mfbt/moz.build
+++ b/mfbt/moz.build
@@ -34,16 +34,17 @@ EXPORTS.mozilla = [
     'DebugOnly.h',
     'decimal/Decimal.h',
     'double-conversion/double-conversion.h',
     'double-conversion/utils.h',
     'EndianUtils.h',
     'EnumeratedArray.h',
     'EnumeratedRange.h',
     'EnumSet.h',
+    'EnumTypeTraits.h',
     'FastBernoulliTrial.h',
     'FloatingPoint.h',
     'Function.h',
     'GuardObjects.h',
     'HashFunctions.h',
     'IndexSequence.h',
     'InitializerList.h',
     'IntegerPrintfMacros.h',
new file mode 100644
--- /dev/null
+++ b/mfbt/tests/TestEnumTypeTraits.cpp
@@ -0,0 +1,136 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/IntegerTypeTraits.h"
+#include "mozilla/EnumTypeTraits.h"
+
+using namespace mozilla;
+
+/* Feature check for EnumTypeFitsWithin. */
+
+#define MAKE_FIXED_EMUM_FOR_TYPE(IntType)                               \
+  enum FixedEnumFor_##IntType : IntType {                               \
+    A_##IntType,                                                        \
+    B_##IntType,                                                        \
+    C_##IntType,                                                        \
+  };
+
+template<typename EnumType, typename IntType>
+static void
+TestShouldFit()
+{
+  static_assert(EnumTypeFitsWithin<EnumType, IntType>::value,
+                "Should fit within exact/promoted integral type");
+}
+
+template<typename EnumType, typename IntType>
+static void
+TestShouldNotFit()
+{
+  static_assert(!EnumTypeFitsWithin<EnumType, IntType>::value,
+                "Should not fit within");
+}
+
+int
+main()
+{
+  // check for int8_t
+  MAKE_FIXED_EMUM_FOR_TYPE(int8_t);
+  TestShouldFit<FixedEnumFor_int8_t, int8_t>();
+  TestShouldFit<FixedEnumFor_int8_t, int16_t>();
+  TestShouldFit<FixedEnumFor_int8_t, int32_t>();
+  TestShouldFit<FixedEnumFor_int8_t, int64_t>();
+
+  TestShouldNotFit<FixedEnumFor_int8_t, uint8_t>();
+  TestShouldNotFit<FixedEnumFor_int8_t, uint16_t>();
+  TestShouldNotFit<FixedEnumFor_int8_t, uint32_t>();
+  TestShouldNotFit<FixedEnumFor_int8_t, uint64_t>();
+
+  // check for uint8_t
+  MAKE_FIXED_EMUM_FOR_TYPE(uint8_t);
+  TestShouldFit<FixedEnumFor_uint8_t, uint8_t>();
+  TestShouldFit<FixedEnumFor_uint8_t, uint16_t>();
+  TestShouldFit<FixedEnumFor_uint8_t, uint32_t>();
+  TestShouldFit<FixedEnumFor_uint8_t, uint64_t>();
+
+  TestShouldNotFit<FixedEnumFor_uint8_t, int8_t>();
+  TestShouldFit<FixedEnumFor_uint8_t, int16_t>();
+  TestShouldFit<FixedEnumFor_uint8_t, int32_t>();
+  TestShouldFit<FixedEnumFor_uint8_t, int64_t>();
+
+  // check for int16_t
+  MAKE_FIXED_EMUM_FOR_TYPE(int16_t);
+  TestShouldNotFit<FixedEnumFor_int16_t, int8_t>();
+  TestShouldFit<FixedEnumFor_int16_t, int16_t>();
+  TestShouldFit<FixedEnumFor_int16_t, int32_t>();
+  TestShouldFit<FixedEnumFor_int16_t, int64_t>();
+
+  TestShouldNotFit<FixedEnumFor_int16_t, uint8_t>();
+  TestShouldNotFit<FixedEnumFor_int16_t, uint16_t>();
+  TestShouldNotFit<FixedEnumFor_int16_t, uint32_t>();
+  TestShouldNotFit<FixedEnumFor_int16_t, uint64_t>();
+
+  // check for uint16_t
+  MAKE_FIXED_EMUM_FOR_TYPE(uint16_t);
+  TestShouldNotFit<FixedEnumFor_uint16_t, uint8_t>();
+  TestShouldFit<FixedEnumFor_uint16_t, uint16_t>();
+  TestShouldFit<FixedEnumFor_uint16_t, uint32_t>();
+  TestShouldFit<FixedEnumFor_uint16_t, uint64_t>();
+
+  TestShouldNotFit<FixedEnumFor_uint16_t, int8_t>();
+  TestShouldNotFit<FixedEnumFor_uint16_t, int16_t>();
+  TestShouldFit<FixedEnumFor_uint16_t, int32_t>();
+  TestShouldFit<FixedEnumFor_uint16_t, int64_t>();
+
+  // check for int32_t
+  MAKE_FIXED_EMUM_FOR_TYPE(int32_t);
+  TestShouldNotFit<FixedEnumFor_int32_t, int8_t>();
+  TestShouldNotFit<FixedEnumFor_int32_t, int16_t>();
+  TestShouldFit<FixedEnumFor_int32_t, int32_t>();
+  TestShouldFit<FixedEnumFor_int32_t, int64_t>();
+
+  TestShouldNotFit<FixedEnumFor_int32_t, uint8_t>();
+  TestShouldNotFit<FixedEnumFor_int32_t, uint16_t>();
+  TestShouldNotFit<FixedEnumFor_int32_t, uint32_t>();
+  TestShouldNotFit<FixedEnumFor_int32_t, uint64_t>();
+
+  // check for uint32_t
+  MAKE_FIXED_EMUM_FOR_TYPE(uint32_t);
+  TestShouldNotFit<FixedEnumFor_uint32_t, uint8_t>();
+  TestShouldNotFit<FixedEnumFor_uint32_t, uint16_t>();
+  TestShouldFit<FixedEnumFor_uint32_t, uint32_t>();
+  TestShouldFit<FixedEnumFor_uint32_t, uint64_t>();
+
+  TestShouldNotFit<FixedEnumFor_uint32_t, int8_t>();
+  TestShouldNotFit<FixedEnumFor_uint32_t, int16_t>();
+  TestShouldNotFit<FixedEnumFor_uint32_t, int32_t>();
+  TestShouldFit<FixedEnumFor_uint32_t, int64_t>();
+
+  // check for int64_t
+  MAKE_FIXED_EMUM_FOR_TYPE(int64_t);
+  TestShouldNotFit<FixedEnumFor_int64_t, int8_t>();
+  TestShouldNotFit<FixedEnumFor_int64_t, int16_t>();
+  TestShouldNotFit<FixedEnumFor_int64_t, int32_t>();
+  TestShouldFit<FixedEnumFor_int64_t, int64_t>();
+
+  TestShouldNotFit<FixedEnumFor_int64_t, uint8_t>();
+  TestShouldNotFit<FixedEnumFor_int64_t, uint16_t>();
+  TestShouldNotFit<FixedEnumFor_int64_t, uint32_t>();
+  TestShouldNotFit<FixedEnumFor_int64_t, uint64_t>();
+
+  // check for uint64_t
+  MAKE_FIXED_EMUM_FOR_TYPE(uint64_t);
+  TestShouldNotFit<FixedEnumFor_uint64_t, uint8_t>();
+  TestShouldNotFit<FixedEnumFor_uint64_t, uint16_t>();
+  TestShouldNotFit<FixedEnumFor_uint64_t, uint32_t>();
+  TestShouldFit<FixedEnumFor_uint64_t, uint64_t>();
+
+  TestShouldNotFit<FixedEnumFor_uint64_t, int8_t>();
+  TestShouldNotFit<FixedEnumFor_uint64_t, int16_t>();
+  TestShouldNotFit<FixedEnumFor_uint64_t, int32_t>();
+  TestShouldNotFit<FixedEnumFor_uint64_t, int64_t>();
+
+  return 0;
+}
--- a/mfbt/tests/moz.build
+++ b/mfbt/tests/moz.build
@@ -12,16 +12,17 @@ CppUnitTests([
     'TestBufferList',
     'TestCasting',
     'TestCeilingFloor',
     'TestCheckedInt',
     'TestCountPopulation',
     'TestCountZeroes',
     'TestEndian',
     'TestEnumSet',
+    'TestEnumTypeTraits',
     'TestFastBernoulliTrial',
     'TestFloatingPoint',
     'TestFunction',
     'TestInitializerList',
     'TestIntegerPrintfMacros',
     'TestIntegerRange',
     'TestJSONWriter',
     'TestLinkedList',
--- a/testing/cppunittest.ini
+++ b/testing/cppunittest.ini
@@ -28,16 +28,17 @@ skip-if = os == 'b2g' || (os == 'android
 [TestCountZeroes]
 [TestDeadlockDetector]
 skip-if = os == 'b2g' || (os == 'android' && debug) # Bug 1054249
 [TestDeadlockDetectorScalability]
 [TestDllInterceptor]
 skip-if = os != 'win'
 [TestEndian]
 [TestEnumSet]
+[TestEnumTypeTraits]
 [TestFastBernoulliTrial]
 [TestFile]
 [TestFloatingPoint]
 [TestFunction]
 [TestGetURL]
 [TestHashtables]
 [TestID]
 [TestInitializerList]