Export of internal Abseil changes.

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3d20ce6cd6541579abecaba169d4b8716d511272 by Jon Cohen <cohenjon@google.com>:

Only use LSAN for clang version >= 3.5.  This should fix https://github.com/abseil/abseil-cpp/issues/244

PiperOrigin-RevId: 234675129

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e15bd4ec7a81aa95cc3d09fa1e0e81d58ae478fb by Conrad Parker <conradparker@google.com>:

Fix errors in apply() sample code

The following changes are made:
 * Make the example method public.
 * Give the two user functions different names to avoid confusion about
   whether apply() can select the correct overload of a function based
   on its tuple argument (it can't).
 * Pass tuple2 to the second example apply() invocation, instead of
   passing its contents individually.
 * Fix a s/tuple/tuple3/ typo in the third example apply() invocation.

PiperOrigin-RevId: 234223407

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de0ed71e21bc76ddf9fe715fdbaef74cd0df95c7 by Abseil Team <absl-team@google.com>:

First test if a macro is defined to avoid -Wundef.

ABSL clients may need to compile their code with the -Wundef warning
flag. It will be helpful if ABSL header files can be compiled without
the -Wundef warning.

How to avoid the -Wundef warning: If a macro may be undefined, we need
to first test whether the macro is defined before testing its value. We
can't rely on the C preprocessor rule that an undefined macro has the
value 0L.

PiperOrigin-RevId: 234201123

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fa484ad7dae0cac21140a96662809ecb0ec8eb5d by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 234185697

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d69b1baef681e27954b065375ecf9c2320463b2b by Samuel Benzaquen <sbenza@google.com>:

Mix pointers more thoroughly.
Some pointer alignments interact badly with the mixing constant. By mixing twice we reduce this problem.

PiperOrigin-RevId: 234178401

--
1041d0e474610f3a8fea0db90958857327d6da1c by Samuel Benzaquen <sbenza@google.com>:

Record rehashes in the hashtablez struct.
Only recording the probe length on insertion causes a huge overestimation of
the total probe length at any given time.

With natural growth, elements are inserted when the load factor is between
(max load/2, max load). However, after a rehash the majority of elements are
actually inserted when the load factor is less than max/2 and have a much lower
average probe length.

Also reset some values when the table is cleared.

PiperOrigin-RevId: 234013580

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299205caf3c89c47339f7409bc831746602cea84 by Mark Barolak <mbar@google.com>:

Fix a sample code snippet that assumes `absl::string_view::const_iterator` is `const char*`.  This is generally true, however in C++17 builds, absl::string_view is an alias for std::string_view and on MSVC, the std::string_view::const_iterator is an object instead of just a pointer.

PiperOrigin-RevId: 233844595

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af6c6370cf51a1e6c1469c79dfb2a486a4009136 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 233773470

--
6e59e4b8e2bb6101b448f0f32b0bea81fe399ccf by Abseil Team <absl-team@google.com>:

fix typo in {Starts|Ends}WithIgnoreCase comment in match.h

PiperOrigin-RevId: 233662951
GitOrigin-RevId: 3d20ce6cd6541579abecaba169d4b8716d511272
Change-Id: Ib9a29b1c38c6aedf5d9f3f7f00596e8d30e864dd

1 files changed, 20 insertions, 12 deletions

diff --git a/absl/utility/utility.h b/absl/utility/utility.h
index aef4baa02dcd..104ec82939d6 100644
--- a/absl/utility/utility.h
+++ b/absl/utility/utility.h
@@ -234,25 +234,33 @@ auto apply_helper(Functor&& functor, Tuple&& t, index_sequence<Indexes...>)
 //
 // Example:
 //
-//   class Foo{void Bar(int);};
-//   void user_function(int, string);
-//   void user_function(std::unique_ptr<Foo>);
+//   class Foo {
+//    public:
+//     void Bar(int);
+//   };
+//   void user_function1(int, string);
+//   void user_function2(std::unique_ptr<Foo>);
+//   auto user_lambda = [](int, int) {};
 //
 //   int main()
 //   {
 //       std::tuple<int, string> tuple1(42, "bar");
-//       // Invokes the user function overload on int, string.
-//       absl::apply(&user_function, tuple1);
+//       // Invokes the first user function on int, string.
+//       absl::apply(&user_function1, tuple1);
 //
-//       auto foo = absl::make_unique<Foo>();
-//       std::tuple<Foo*, int> tuple2(foo.get(), 42);
-//       // Invokes the method Bar on foo with one argument 42.
-//       absl::apply(&Foo::Bar, foo.get(), 42);
-//
-//       std::tuple<std::unique_ptr<Foo>> tuple3(absl::make_unique<Foo>());
+//       std::tuple<std::unique_ptr<Foo>> tuple2(absl::make_unique<Foo>());
 //       // Invokes the user function that takes ownership of the unique
 //       // pointer.
-//       absl::apply(&user_function, std::move(tuple));
+//       absl::apply(&user_function2, std::move(tuple2));
+//
+//       auto foo = absl::make_unique<Foo>();
+//       std::tuple<Foo*, int> tuple3(foo.get(), 42);
+//       // Invokes the method Bar on foo with one argument, 42.
+//       absl::apply(&Foo::Bar, tuple3);
+//
+//       std::tuple<int, int> tuple4(8, 9);
+//       // Invokes a lambda.
+//       absl::apply(user_lambda, tuple4);
 //   }
 template <typename Functor, typename Tuple>
 auto apply(Functor&& functor, Tuple&& t)