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diff --git a/ipc/glue/EnumSerializer.h b/ipc/glue/EnumSerializer.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef __IPC_GLUE_ENUMSERIALIZER_H__
+#define __IPC_GLUE_ENUMSERIALIZER_H__
+
+#include "CrashAnnotations.h"
+#include "chrome/common/ipc_message_utils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/IntegerTypeTraits.h"
+#include "nsExceptionHandler.h"
+#include "nsLiteralString.h"
+#include "nsString.h"
+#include "nsTLiteralString.h"
+
+class PickleIterator;
+
+namespace IPC {
+class Message;
+class MessageReader;
+class MessageWriter;
+}  // namespace IPC
+
+#ifdef _MSC_VER
+#  pragma warning(disable : 4800)
+#endif
+
+namespace IPC {
+
+/**
+ * Generic enum serializer.
+ *
+ * Consider using the specializations below, such as ContiguousEnumSerializer.
+ *
+ * This is a generic serializer for any enum type used in IPDL.
+ * Programmers can define ParamTraits<E> for enum type E by deriving
+ * EnumSerializer<E, MyEnumValidator> where MyEnumValidator is a struct
+ * that has to define a static IsLegalValue function returning whether
+ * a given value is a legal value of the enum type at hand.
+ *
+ * \sa https://developer.mozilla.org/en/IPDL/Type_Serialization
+ */
+template <typename E, typename EnumValidator>
+struct EnumSerializer {
+  typedef E paramType;
+
+  // XXX(Bug 1690343) Should this be changed to
+  // std::make_unsigned_t<std::underlying_type_t<paramType>>, to make this more
+  // consistent with the type used for validating values?
+  typedef typename mozilla::UnsignedStdintTypeForSize<sizeof(paramType)>::Type
+      uintParamType;
+
+  static void Write(MessageWriter* aWriter, const paramType& aValue) {
+    // XXX This assertion is somewhat meaningless at least for E that don't have
+    // a fixed underlying type: if aValue weren't a legal value, we would
+    // already have UB where this function is called.
+    MOZ_RELEASE_ASSERT(EnumValidator::IsLegalValue(
+        static_cast<std::underlying_type_t<paramType>>(aValue)));
+    WriteParam(aWriter, uintParamType(aValue));
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    uintParamType value;
+    if (!ReadParam(aReader, &value)) {
+      CrashReporter::AnnotateCrashReport(
+          CrashReporter::Annotation::IPCReadErrorReason, "Bad iter"_ns);
+      return false;
+    } else if (!EnumValidator::IsLegalValue(value)) {
+      CrashReporter::AnnotateCrashReport(
+          CrashReporter::Annotation::IPCReadErrorReason, "Illegal value"_ns);
+      return false;
+    }
+    *aResult = paramType(value);
+    return true;
+  }
+};
+
+template <typename E, E MinLegal, E HighBound>
+class ContiguousEnumValidator {
+  // Silence overzealous -Wtype-limits bug in GCC fixed in GCC 4.8:
+  // "comparison of unsigned expression >= 0 is always true"
+  // http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11856
+  template <typename T>
+  static bool IsLessThanOrEqual(T a, T b) {
+    return a <= b;
+  }
+
+ public:
+  using IntegralType = std::underlying_type_t<E>;
+  static constexpr auto kMinLegalIntegral = static_cast<IntegralType>(MinLegal);
+  static constexpr auto kHighBoundIntegral =
+      static_cast<IntegralType>(HighBound);
+
+  static bool IsLegalValue(const IntegralType e) {
+    return IsLessThanOrEqual(kMinLegalIntegral, e) && e < kHighBoundIntegral;
+  }
+};
+
+template <typename E, E MinLegal, E MaxLegal>
+class ContiguousEnumValidatorInclusive {
+  // Silence overzealous -Wtype-limits bug in GCC fixed in GCC 4.8:
+  // "comparison of unsigned expression >= 0 is always true"
+  // http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11856
+  template <typename T>
+  static bool IsLessThanOrEqual(T a, T b) {
+    return a <= b;
+  }
+
+ public:
+  using IntegralType = std::underlying_type_t<E>;
+  static constexpr auto kMinLegalIntegral = static_cast<IntegralType>(MinLegal);
+  static constexpr auto kMaxLegalIntegral = static_cast<IntegralType>(MaxLegal);
+
+  static bool IsLegalValue(const IntegralType e) {
+    return IsLessThanOrEqual(kMinLegalIntegral, e) && e <= kMaxLegalIntegral;
+  }
+};
+
+template <typename E, E AllBits>
+struct BitFlagsEnumValidator {
+  static bool IsLegalValue(const std::underlying_type_t<E> e) {
+    return (e & static_cast<std::underlying_type_t<E>>(AllBits)) == e;
+  }
+};
+
+/**
+ * Specialization of EnumSerializer for enums with contiguous enum values.
+ *
+ * Provide two values: MinLegal, HighBound. An enum value x will be
+ * considered legal if MinLegal <= x < HighBound.
+ *
+ * For example, following is definition of serializer for enum type FOO.
+ * \code
+ * enum FOO { FOO_FIRST, FOO_SECOND, FOO_LAST, NUM_FOO };
+ *
+ * template <>
+ * struct ParamTraits<FOO>:
+ *     public ContiguousEnumSerializer<FOO, FOO_FIRST, NUM_FOO> {};
+ * \endcode
+ * FOO_FIRST, FOO_SECOND, and FOO_LAST are valid value.
+ */
+template <typename E, E MinLegal, E HighBound>
+struct ContiguousEnumSerializer
+    : EnumSerializer<E, ContiguousEnumValidator<E, MinLegal, HighBound>> {};
+
+/**
+ * This is similar to ContiguousEnumSerializer, but the last template
+ * parameter is expected to be the highest legal value, rather than a
+ * sentinel value. This is intended to support enumerations that don't
+ * have sentinel values.
+ */
+template <typename E, E MinLegal, E MaxLegal>
+struct ContiguousEnumSerializerInclusive
+    : EnumSerializer<E,
+                     ContiguousEnumValidatorInclusive<E, MinLegal, MaxLegal>> {
+};
+
+/**
+ * Specialization of EnumSerializer for enums representing bit flags.
+ *
+ * Provide one value: AllBits. An enum value x will be
+ * considered legal if (x & AllBits) == x;
+ *
+ * Example:
+ * \code
+ * enum FOO {
+ *   FOO_FIRST =  1 << 0,
+ *   FOO_SECOND = 1 << 1,
+ *   FOO_LAST =   1 << 2,
+ *   ALL_BITS =   (1 << 3) - 1
+ * };
+ *
+ * template <>
+ * struct ParamTraits<FOO>:
+ *     public BitFlagsEnumSerializer<FOO, FOO::ALL_BITS> {};
+ * \endcode
+ */
+template <typename E, E AllBits>
+struct BitFlagsEnumSerializer
+    : EnumSerializer<E, BitFlagsEnumValidator<E, AllBits>> {};
+
+} /* namespace IPC */
+
+#endif /* __IPC_GLUE_ENUMSERIALIZER_H__ */