comparison osx/include/kj/common.h @ 147:45360b968bf4

Cap'n Proto v0.6 + build for OSX

     #endif
   #endif
 #elif defined(_MSC_VER)
   #if _MSC_VER < 1900
     #error "You need Visual Studio 2015 or better to compile this code."
-  #elif !CAPNP_LITE
-    // TODO(cleanup): This is KJ, but we're talking about Cap'n Proto.
-    #error "As of this writing, Cap'n Proto only supports Visual C++ in 'lite mode'; please #define CAPNP_LITE"
   #endif
 #else
   #warning "I don't recognize your compiler.  As of this writing, Clang and GCC are the only "\
            "known compilers with enough C++11 support for this library.  "\
            "#define KJ_NO_COMPILER_CHECK to make this warning go away."

 // widely present in the wild e.g. on Ubuntu 14.04.
 #undef _GLIBCXX_HAVE_GETS
 #endif
 
 #if defined(_MSC_VER)
+#ifndef NOMINMAX
+#define NOMINMAX 1
+#endif
 #include <intrin.h>  // __popcnt
 #endif
 
 // =======================================================================================
 

 #define KJ_LIKELY(condition) (condition)
 #define KJ_UNLIKELY(condition) (condition)
 #endif
 
 #if defined(KJ_DEBUG) || __NO_INLINE__
-#define KJ_ALWAYS_INLINE(prototype) inline prototype
+#define KJ_ALWAYS_INLINE(...) inline __VA_ARGS__
 // Don't force inline in debug mode.
 #else
 #if defined(_MSC_VER)
-#define KJ_ALWAYS_INLINE(prototype) __forceinline prototype
-#else
-#define KJ_ALWAYS_INLINE(prototype) inline prototype __attribute__((always_inline))
+#define KJ_ALWAYS_INLINE(...) __forceinline __VA_ARGS__
+#else
+#define KJ_ALWAYS_INLINE(...) inline __VA_ARGS__ __attribute__((always_inline))
 #endif
 // Force a function to always be inlined.  Apply only to the prototype, not to the definition.
 #endif
 
 #if defined(_MSC_VER)

   //
   // Note that due to C++ rules about implicit copy constructors and assignment operators, any
   // type that contains or inherits from a type that disallows const copies will also automatically
   // disallow const copies.  Hey, cool, that's exactly what we want.
 
+#if CAPNP_DEBUG_TYPES
+  // Alas! Declaring a defaulted non-const copy constructor tickles a bug which causes GCC and
+  // Clang to disagree on ABI, using different calling conventions to pass this type, leading to
+  // immediate segfaults. See:
+  //     https://bugs.llvm.org/show_bug.cgi?id=23764
+  //     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58074
+  //
+  // Because of this, we can't use this technique. We guard it by CAPNP_DEBUG_TYPES so that it
+  // still applies to the Cap'n Proto developers during internal testing.
+
   DisallowConstCopy() = default;
   DisallowConstCopy(DisallowConstCopy&) = default;
   DisallowConstCopy(DisallowConstCopy&&) = default;
   DisallowConstCopy& operator=(DisallowConstCopy&) = default;
   DisallowConstCopy& operator=(DisallowConstCopy&&) = default;
+#endif
 };
+
+#if _MSC_VER
+
+#define KJ_CPCAP(obj) obj=::kj::cp(obj)
+// TODO(msvc): MSVC refuses to invoke non-const versions of copy constructors in by-value lambda
+// captures. Wrap your captured object in this macro to force the compiler to perform a copy.
+// Example:
+//
+//   struct Foo: DisallowConstCopy {};
+//   Foo foo;
+//   auto lambda = [KJ_CPCAP(foo)] {};
+
+#else
+
+#define KJ_CPCAP(obj) obj
+// Clang and gcc both already perform copy capturing correctly with non-const copy constructors.
+
+#endif
 
 template <typename T>
 struct DisallowConstCopyIfNotConst: public DisallowConstCopy {
   // Inherit from this when implementing a template that contains a pointer to T and which should
   // enforce transitive constness.  If T is a const type, this has no effect.  Otherwise, it is

 template <typename T, typename U>
 constexpr bool canConvert() {
   return sizeof(CanConvert_<U>::sfinae(instance<T>())) == sizeof(int);
 }
 
-#if __clang__
+#if __GNUC__ && !__clang__ && __GNUC__ < 5
 template <typename T>
 constexpr bool canMemcpy() {
   // Returns true if T can be copied using memcpy instead of using the copy constructor or
   // assignment operator.
 
-  // Clang unhelpfully defines __has_trivial_{copy,assign}(T) to be true if the copy constructor /
-  // assign operator are deleted, on the basis that a strict reading of the definition of "trivial"
-  // according to the standard says that deleted functions are in fact trivial.  Meanwhile Clang
-  // provides these admittedly-better intrinsics, but GCC does not.
-  return __is_trivially_constructible(T, const T&) && __is_trivially_assignable(T, const T&);
-}
+  // GCC 4 does not have __is_trivially_constructible and friends, and there doesn't seem to be
+  // any reliable alternative. __has_trivial_copy() and __has_trivial_assign() return the right
+  // thing at one point but later on they changed such that a deleted copy constructor was
+  // considered "trivial" (apparently technically correct, though useless). So, on GCC 4 we give up
+  // and assume we can't memcpy() at all, and must explicitly copy-construct everything.
+  return false;
+}
+#define KJ_ASSERT_CAN_MEMCPY(T)
 #else
 template <typename T>
 constexpr bool canMemcpy() {
   // Returns true if T can be copied using memcpy instead of using the copy constructor or
   // assignment operator.
 
-  // GCC defines these to mean what we want them to mean.
-  return __has_trivial_copy(T) && __has_trivial_assign(T);
-}
+  return __is_trivially_constructible(T, const T&) && __is_trivially_assignable(T, const T&);
+}
+#define KJ_ASSERT_CAN_MEMCPY(T) \
+  static_assert(kj::canMemcpy<T>(), "this code expects this type to be memcpy()-able");
 #endif
 
 // =======================================================================================
 // Equivalents to std::move() and std::forward(), since these are very commonly needed and the
 // std header <utility> pulls in lots of other stuff.

 
 template<typename T> constexpr T cp(T& t) noexcept { return t; }
 template<typename T> constexpr T cp(const T& t) noexcept { return t; }
 // Useful to force a copy, particularly to pass into a function that expects T&&.
 
-template <typename T, typename U, bool takeT> struct MinType_;
-template <typename T, typename U> struct MinType_<T, U, true> { typedef T Type; };
-template <typename T, typename U> struct MinType_<T, U, false> { typedef U Type; };
+template <typename T, typename U, bool takeT, bool uOK = true> struct ChooseType_;
+template <typename T, typename U> struct ChooseType_<T, U, true, true> { typedef T Type; };
+template <typename T, typename U> struct ChooseType_<T, U, true, false> { typedef T Type; };
+template <typename T, typename U> struct ChooseType_<T, U, false, true> { typedef U Type; };
 
 template <typename T, typename U>
-using MinType = typename MinType_<T, U, sizeof(T) <= sizeof(U)>::Type;
-// Resolves to the smaller of the two input types.
+using WiderType = typename ChooseType_<T, U, sizeof(T) >= sizeof(U)>::Type;
 
 template <typename T, typename U>
-inline constexpr auto min(T&& a, U&& b) -> MinType<Decay<T>, Decay<U>> {
-  return a < b ? MinType<Decay<T>, Decay<U>>(a) : MinType<Decay<T>, Decay<U>>(b);
-}
-
-template <typename T, typename U, bool takeT> struct MaxType_;
-template <typename T, typename U> struct MaxType_<T, U, true> { typedef T Type; };
-template <typename T, typename U> struct MaxType_<T, U, false> { typedef U Type; };
+inline constexpr auto min(T&& a, U&& b) -> WiderType<Decay<T>, Decay<U>> {
+  return a < b ? WiderType<Decay<T>, Decay<U>>(a) : WiderType<Decay<T>, Decay<U>>(b);
+}
 
 template <typename T, typename U>
-using MaxType = typename MaxType_<T, U, sizeof(T) >= sizeof(U)>::Type;
-// Resolves to the larger of the two input types.
-
-template <typename T, typename U>
-inline constexpr auto max(T&& a, U&& b) -> MaxType<Decay<T>, Decay<U>> {
-  return a > b ? MaxType<Decay<T>, Decay<U>>(a) : MaxType<Decay<T>, Decay<U>>(b);
+inline constexpr auto max(T&& a, U&& b) -> WiderType<Decay<T>, Decay<U>> {
+  return a > b ? WiderType<Decay<T>, Decay<U>>(a) : WiderType<Decay<T>, Decay<U>>(b);
 }
 
 template <typename T, size_t s>
 inline constexpr size_t size(T (&arr)[s]) { return s; }
 template <typename T>

 // of that type.  This is useful to use as e.g. a parameter to a function because it will be robust
 // in the face of changes to the parameter's type.
 //
 // `char` is not supported, but `signed char` and `unsigned char` are.
 
+template <typename T>
+inline bool operator==(T t, MaxValue_) { return t == Decay<T>(maxValue); }
+template <typename T>
+inline bool operator==(T t, MinValue_) { return t == Decay<T>(minValue); }
+
+template <uint bits>
+inline constexpr unsigned long long maxValueForBits() {
+  // Get the maximum integer representable in the given number of bits.
+
+  // 1ull << 64 is unfortunately undefined.
+  return (bits == 64 ? 0 : (1ull << bits)) - 1;
+}
+
+struct ThrowOverflow {
+  // Functor which throws an exception complaining about integer overflow. Usually this is used
+  // with the interfaces in units.h, but is defined here because Cap'n Proto wants to avoid
+  // including units.h when not using CAPNP_DEBUG_TYPES.
+  void operator()() const;
+};
+
 #if __GNUC__
 inline constexpr float inf() { return __builtin_huge_valf(); }
 inline constexpr float nan() { return __builtin_nanf(""); }
 
 #elif _MSC_VER

 
 template <typename T>
 class Range {
 public:
   inline constexpr Range(const T& begin, const T& end): begin_(begin), end_(end) {}
+  inline explicit constexpr Range(const T& end): begin_(0), end_(end) {}
 
   class Iterator {
   public:
     Iterator() = default;
     inline Iterator(const T& value): value(value) {}

 private:
   T begin_;
   T end_;
 };
 
+template <typename T, typename U>
+inline constexpr Range<WiderType<Decay<T>, Decay<U>>> range(T begin, U end) {
+  return Range<WiderType<Decay<T>, Decay<U>>>(begin, end);
+}
+
 template <typename T>
 inline constexpr Range<Decay<T>> range(T begin, T end) { return Range<Decay<T>>(begin, end); }
 // Returns a fake iterable container containing all values of T from `begin` (inclusive) to `end`
 // (exclusive).  Example:
 //
 //     // Prints 1, 2, 3, 4, 5, 6, 7, 8, 9.
 //     for (int i: kj::range(1, 10)) { print(i); }
+
+template <typename T>
+inline constexpr Range<Decay<T>> zeroTo(T end) { return Range<Decay<T>>(end); }
+// Returns a fake iterable container containing all values of T from zero (inclusive) to `end`
+// (exclusive).  Example:
+//
+//     // Prints 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
+//     for (int i: kj::zeroTo(10)) { print(i); }
 
 template <typename T>
 inline constexpr Range<size_t> indices(T&& container) {
   // Shortcut for iterating over the indices of a container:
   //

 
   inline Iterator begin() const { return Iterator(value, 0); }
   inline Iterator end() const { return Iterator(value, count); }
 
   inline size_t size() const { return count; }
+  inline const T& operator[](ptrdiff_t) const { return value; }
 
 private:
   T value;
   size_t count;
 };

 template <typename T>
 class Maybe;
 
 namespace _ {  // private
 
-#if _MSC_VER
-  // TODO(msvc): MSVC barfs on noexcept(instance<T&>().~T()) where T = kj::Exception and
-  // kj::_::Void. It and every other factorization I've tried produces:
-  //   error C2325: 'kj::Blah' unexpected type to the right of '.~': expected 'void'
-#define MSVC_NOEXCEPT_DTOR_WORKAROUND(T) __is_nothrow_destructible(T)
-#else
-#define MSVC_NOEXCEPT_DTOR_WORKAROUND(T) noexcept(instance<T&>().~T())
-#endif
-
 template <typename T>
 class NullableValue {
   // Class whose interface behaves much like T*, but actually contains an instance of T and a
   // boolean flag indicating nullness.
 

       : isSet(other.isSet) {
     if (isSet) {
       ctor(value, other.value);
     }
   }
-  inline ~NullableValue() noexcept(MSVC_NOEXCEPT_DTOR_WORKAROUND(T)) {
+  inline ~NullableValue()
+#if _MSC_VER
+      // TODO(msvc): MSVC has a hard time with noexcept specifier expressions that are more complex
+      //   than `true` or `false`. We had a workaround for VS2015, but VS2017 regressed.
+      noexcept(false)
+#else
+      noexcept(noexcept(instance<T&>().~T()))
+#endif
+  {
     if (isSet) {
       dtor(value);
     }
   }
 

   Maybe(Maybe& other): ptr(other.ptr) {}
 
   template <typename U>
   Maybe(Maybe<U>&& other) noexcept(noexcept(T(instance<U&&>()))) {
     KJ_IF_MAYBE(val, kj::mv(other)) {
-      ptr = *val;
+      ptr.emplace(kj::mv(*val));
     }
   }
   template <typename U>
   Maybe(const Maybe<U>& other) {
     KJ_IF_MAYBE(val, other) {
-      ptr = *val;
+      ptr.emplace(*val);
     }
   }
 
   Maybe(decltype(nullptr)) noexcept: ptr(nullptr) {}