Revert "Move headers used by headers in include/ to include/private."

This reverts commit a89f55198bdc58f0b6f6196907ab25a6afc1a661.

Reason: breaking the roll.

TBR=mtklein@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1216033008

1 files changed, 111 insertions, 0 deletions

diff --git a/src/utils/SkTLogic.h b/src/utils/SkTLogic.h
new file mode 100644
index 0000000000..d188242446
--- /dev/null
+++ b/src/utils/SkTLogic.h
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ *
+ * This header provides some of the helpers (std::integral_constant) and
+ * type transformations (std::conditional) which will become available with
+ * C++11 in the type_traits header.
+ *
+ * Because we lack constexpr, we cannot mimic
+ * std::integral_constant::'constexpr operator T()'.
+ * As a result we introduce SkTBool and SkTIf similar to Boost in order to
+ * minimize the visual noise of many uses of '::value'.
+ */
+
+#ifndef SkTLogic_DEFINED
+#define SkTLogic_DEFINED
+
+/** Represents a templated integer constant.
+ *  Pre-C++11 version of std::integral_constant.
+ */
+template <typename T, T v> struct SkTIntegralConstant {
+    static const T value = v;
+    typedef T value_type;
+    typedef SkTIntegralConstant<T, v> type;
+};
+
+/** Convenience specialization of SkTIntegralConstant. */
+template <bool b> struct SkTBool : SkTIntegralConstant<bool, b> { };
+
+/** Pre-C++11 version of std::is_empty<T>. */
+template <typename T>
+class SkTIsEmpty {
+    struct Derived : public T { char unused; };
+public:
+    static const bool value = sizeof(Derived) == sizeof(char);
+};
+
+/** Pre-C++11 version of std::true_type. */
+typedef SkTBool<true> SkTrue;
+
+/** Pre-C++11 version of std::false_type. */
+typedef SkTBool<false> SkFalse;
+
+/** SkTIf_c::type = (condition) ? T : F;
+ *  Pre-C++11 version of std::conditional.
+ */
+template <bool condition, typename T, typename F> struct SkTIf_c {
+    typedef F type;
+};
+template <typename T, typename F> struct SkTIf_c<true, T, F> {
+    typedef T type;
+};
+
+/** SkTIf::type = (Condition::value) ? T : F; */
+template <typename Condition, typename T, typename F> struct SkTIf {
+    typedef typename SkTIf_c<static_cast<bool>(Condition::value), T, F>::type type;
+};
+
+/** SkTMux::type = (a && b) ? Both : (a) ? A : (b) ? B : Neither; */
+template <typename a, typename b, typename Both, typename A, typename B, typename Neither>
+struct SkTMux {
+    typedef typename SkTIf<a, typename SkTIf<b, Both, A>::type,
+                              typename SkTIf<b, B, Neither>::type>::type type;
+};
+
+/** SkTEnableIf_c::type = (condition) ? T : [does not exist]; */
+template <bool condition, class T = void> struct SkTEnableIf_c { };
+template <class T> struct SkTEnableIf_c<true, T> {
+    typedef T type;
+};
+
+/** SkTEnableIf::type = (Condition::value) ? T : [does not exist]; */
+template <class Condition, class T = void> struct SkTEnableIf
+    : public SkTEnableIf_c<static_cast<bool>(Condition::value), T> { };
+
+/** Use as a return type to enable a function only when cond_type::value is true,
+ *  like C++14's std::enable_if_t.  E.g.  (N.B. this is a dumb example.)
+ *  SK_WHEN(SkTrue, int) f(void* ptr) { return 1; }
+ *  SK_WHEN(!SkTrue, int) f(void* ptr) { return 2; }
+ */
+#define SK_WHEN(cond_prefix, T) typename SkTEnableIf_c<cond_prefix::value, T>::type
+#define SK_WHEN_C(cond, T) typename SkTEnableIf_c<cond, T>::type
+
+// See http://en.wikibooks.org/wiki/More_C++_Idioms/Member_Detector
+#define SK_CREATE_MEMBER_DETECTOR(member)                                           \
+template <typename T>                                                               \
+class HasMember_##member {                                                          \
+    struct Fallback { int member; };                                                \
+    struct Derived : T, Fallback {};                                                \
+    template <typename U, U> struct Check;                                          \
+    template <typename U> static uint8_t func(Check<int Fallback::*, &U::member>*); \
+    template <typename U> static uint16_t func(...);                                \
+public:                                                                             \
+    typedef HasMember_##member type;                                                \
+    static const bool value = sizeof(func<Derived>(NULL)) == sizeof(uint16_t);      \
+}
+
+// Same sort of thing as SK_CREATE_MEMBER_DETECTOR, but checks for the existence of a nested type.
+#define SK_CREATE_TYPE_DETECTOR(type)                                   \
+template <typename T>                                                   \
+class HasType_##type {                                                  \
+    template <typename U> static uint8_t func(typename U::type*);       \
+    template <typename U> static uint16_t func(...);                    \
+public:                                                                 \
+    static const bool value = sizeof(func<T>(NULL)) == sizeof(uint8_t); \
+}
+
+#endif