Squashed 'third_party/abseil/' changes from ddf8e52a2..384af0e91
384af0e91 Export of internal Abseil changes
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9f8b87b71 Add missing word 'library' in the 'status' description (#868)
e2b1bab19 Export of internal Abseil changes
1bae23e32 Export of internal Abseil changes
6df644c56 Include the status library into the main README. (#863)
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6b03bf543 fix build dll (#797)
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731852f10 Fix stacktrace on aarch64 architecture. Fixes #805 (#827)
2e5f2bcfd moved deleted functions to public for better compiler errors. (#828)
e9e9b9fc7 Export of internal Abseil changes
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e493d6acb fix compile fails with asan and -Wredundant-decls (#801)
e63a5a610 Export of internal Abseil changes
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40fdb59d3 btree: fix sign-compare warnings (#800)
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9927a0989 Export of internal Abseil changes
7680a5f8e Added missing asserts for seq.index() < capacity_ and unified their usage based on has_element(). (#781)
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2c8a5b0d8 Export of internal Abseil changes
41a6263fd Export of internal Abseil changes
3c2bed2e7 Export of internal Abseil changes
ea8a689cf fix build on P9 (#739)
672d9e0ae Export of internal Abseil changes
f624790b7 Export of internal Abseil changes
55c04eb92 Export of internal Abseil changes
302b250e1 Disable pthread for standalone wasm build support (#721)
61d8bc057 Merge branch 'master' of https://github.com/abseil/abseil-cpp into master
4b5b25a28 cmake: remove unneeded enable_testing() cmd (#736)
63f2c695e cmake: flag conformance_testing as TESTONLY (#737)
d5269a8b6 Export of internal Abseil changes
23f1f9cf6 Typo in comment (#733)
259301a52 Fix CMake path for INSTALL_INCLUDEDIR (#723)
dc464c1dc Allow overriding Abseil IDE folder (#724)
bf655de09 Export of internal Abseil changes
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1d31b5c36 Export of internal Abseil changes
da3a87690 Export of internal Abseil changes
8faf20461 Exclude empty directories (#697)
2069dc796 Export of internal Abseil changes
4832bf6bf Added a BUILD file in root to expose license. (#695)
af8f994af Export of internal Abseil changes
33caf1097 Export of internal Abseil changes
cf1a02e2d Export of internal Abseil changes
768eb2ca2 Export of internal Abseil changes
3f347c462 Fix build on riscv32 (#675)
62cf6a704 Export of internal Abseil changes
d118d4bb1 Export of internal Abseil changes
f2bc9d11e Fix public target name of the random library (#684)
0fecf0e63 Export of internal Abseil changes
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c45d1c09d Export of internal Abseil changes
a35ef8a62 Export of internal Abseil changes
bd317cae3 Export of internal Abseil changes
b11574465 fix MSVC warning 4245: conversion signed => unsigned during initialization (#678)
d85783fd0 Export of internal Abseil changes
a1d668990 Export of internal Abseil changes
ca9856cab Export of internal Abseil changes
6e18c7115 Export of internal Abseil changes
3f48ce1c4 init (#673)
cde2e2410 Export of internal Abseil changes
68494aae9 Fix CMake Threads dependency issue
902909a43 Export of internal Abseil changes
cb52b05ea Export of internal Abseil changes
1a02b7a20 Use "-lrt" instead of the resolved find_library result when linking librt (#665)
df60c82df Export of internal Abseil changes
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db5773a72 Export of internal Abseil changes
71079e42c Export of internal Abseil changes
2946ac0de Use base_internal::AtomicHook instead of std::atomic (#661)
567bee2f7 Fix ABSL_RANDOM_RANDEN_COPTS setting on FreeBSD (#664)
bf6166a63 Export of internal Abseil changes
111260963 Export of internal Abseil changes
73ea9a957 Export of internal Abseil changes
c01b9916e Add option to use an externally provided GoogleTest target (for usage of abseil as add_subdirectory target) (#647)
d43b7997c Export of internal Abseil changes
62f05b1f5 Export of internal Abseil changes
fba8a316c Export of internal Abseil changes
79e0dc115 Export of internal Abseil changes
132d791b4 bazel: Add missing load statements for cc_binary (#645)
518f17501 Export of internal Abseil changes
092ed9793 Export of internal Abseil changes
2d2a8aea2 Export of internal Abseil changes
7853a7586 Export of internal Abseil changes
c6954897f Export of internal Abseil changes
b92f35f65 Fix CompressedTuple move constructor on MSVC (#637)
a877af1f2 Export of internal Abseil changes
d936052d3 Export of internal Abseil changes
238b9a59c Skip the .exe suffix in the helpshort filter on Windows (#629)
417ea99cb UWP doesn't allow reading regkeys (#594)
40a0e58eb Export of internal Abseil changes
cf3a1998e Export of internal Abseil changes
b19ba9676 Export of internal Abseil changes
06f0e767d BuildBreak: UWP apps can't call GetModuleHandle (#596)
bcefbdcdf Export of internal Abseil changes
0033c9ea9 Fix build on FreeBSD/powerpc (#616)
0d5ce2797 Export of internal Abseil changes
b69c7d880 Export of internal Abseil changes
2a5633fc0 Merge "Export of internal Abseil changes"
f9b3d6e49 Add RISCV support to GetProgramCounter() (#621)
914ff4451 Export of internal Abseil changes
0232c87f2 Add missing ABSL_HAVE_VDSO_SUPPORT conditional (#622)
3c8141051 Export of internal Abseil changes
c44657f55 Export of internal Abseil changes
98eb410c9 Export of internal Abseil changes
bf78e9773 Export of internal Abseil changes
d95d15671 Export of internal Abseil changes
24713a703 Export of internal Abseil changes
72382c21f Export of internal Abseil changes
08a7e7bf9 Export of internal Abseil changes
36bcd9599 Fix pointer format specifier in documentation (#614)
0f86336b6 Export of internal Abseil changes
c512f118d Export of internal Abseil changes
37dd2562e Export of internal Abseil changes
444277026 fix: Add support for more ARM processors detection (#608)
159bf2bf6 Export of internal Abseil changes
a2e6adecc Use https links. (#586)
564001ae5 Export of internal Abseil changes
b3aaac8a3 Export of internal Abseil changes
63ee2f887 Export of internal Abseil changes
a048203a8 Export of internal Abseil changes
1de016636 Export of internal Abseil changes
ad904b6cd Export of internal Abseil changes
7bd1935dc cmake: Fix x86_64 check on Windows for random copts (#518)
292351391 Export of internal Abseil changes
bf86cfe16 Export of internal Abseil changes
12bc53e03 Export of internal Abseil changes
1e39f8626 Export of internal Abseil changes
77f87009a Export of internal Abseil changes
d659fe54b Export of internal Abseil changes
a4b757b5d Export of internal Abseil changes
0514227d2 Export of internal Abseil changes
7f4fe64af Export of internal Abseil changes
16d9fd58a Export of internal Abseil changes
bcaae6009 Export of internal Abseil changes
8ba96a824 Export of internal Abseil changes
2103fd9ac Export of internal Abseil changes
3df7b52a6 Export of internal Abseil changes
fa8c75182 Export of internal Abseil changes
85092b4b6 Fix Conan builds (#400)
e96ae2203 Export of internal Abseil changes
20de2db74 Export of internal Abseil changes
846e5dbed Export of internal Abseil changes
83880e3d8 Merge branch 'master' of https://github.com/abseil/abseil-cpp
8207907f4 Export of internal Abseil changes
39d68a422 docs: fix typo (#397)
078b89b3c Export of internal Abseil changes
19b021cb3 Export of internal Abseil changes
ecc0033b5 Always enable proper symbolize implementation on Windows (#257)
2796d500a Export of internal Abseil changes
e4c8d0eb8 Export of internal Abseil changes
a15364ce4 Export of internal Abseil changes
ab3552a18 Export of internal Abseil changes
e9f9000c7 Fix ABSL_WAITER_MODE detection for mingw (#342)
abea769b5 Fix ABSL_HAVE_ALARM check on mingw (#341)
25597bdfc Export of internal Abseil changes
aad33fefa Export of internal Abseil changes
8fe7214fe Export of internal Abseil changes
debac94cf Export of internal Abseil changes
882b3501a Fix spelling errors (#384)
502efe6d7 Export of internal Abseil changes
ccdd1d57b Export of internal Abseil changes
Change-Id: I59864a0053f6e03d88cc9d5e2a92757039a05484
git-subtree-dir: third_party/abseil
git-subtree-split: 384af0e9141283172e2bff3210dae79fb7130d9c
diff --git a/absl/functional/BUILD.bazel b/absl/functional/BUILD.bazel
new file mode 100644
index 0000000..ebd9b99
--- /dev/null
+++ b/absl/functional/BUILD.bazel
@@ -0,0 +1,93 @@
+#
+# Copyright 2019 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
+load(
+ "//absl:copts/configure_copts.bzl",
+ "ABSL_DEFAULT_COPTS",
+ "ABSL_DEFAULT_LINKOPTS",
+ "ABSL_TEST_COPTS",
+)
+
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+cc_library(
+ name = "bind_front",
+ srcs = ["internal/front_binder.h"],
+ hdrs = ["bind_front.h"],
+ copts = ABSL_DEFAULT_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ "//absl/base:base_internal",
+ "//absl/container:compressed_tuple",
+ "//absl/meta:type_traits",
+ "//absl/utility",
+ ],
+)
+
+cc_test(
+ name = "bind_front_test",
+ srcs = ["bind_front_test.cc"],
+ copts = ABSL_TEST_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ ":bind_front",
+ "//absl/memory",
+ "@com_google_googletest//:gtest_main",
+ ],
+)
+
+cc_library(
+ name = "function_ref",
+ srcs = ["internal/function_ref.h"],
+ hdrs = ["function_ref.h"],
+ copts = ABSL_DEFAULT_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ "//absl/base:base_internal",
+ "//absl/meta:type_traits",
+ ],
+)
+
+cc_test(
+ name = "function_ref_test",
+ size = "small",
+ srcs = ["function_ref_test.cc"],
+ copts = ABSL_TEST_COPTS,
+ deps = [
+ ":function_ref",
+ "//absl/container:test_instance_tracker",
+ "//absl/memory",
+ "@com_google_googletest//:gtest_main",
+ ],
+)
+
+cc_test(
+ name = "function_ref_benchmark",
+ srcs = [
+ "function_ref_benchmark.cc",
+ ],
+ copts = ABSL_TEST_COPTS,
+ tags = ["benchmark"],
+ visibility = ["//visibility:private"],
+ deps = [
+ ":function_ref",
+ "//absl/base:core_headers",
+ "@com_github_google_benchmark//:benchmark_main",
+ ],
+)
diff --git a/absl/functional/CMakeLists.txt b/absl/functional/CMakeLists.txt
new file mode 100644
index 0000000..cda914f
--- /dev/null
+++ b/absl/functional/CMakeLists.txt
@@ -0,0 +1,72 @@
+#
+# Copyright 2019 The Abseil Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+absl_cc_library(
+ NAME
+ bind_front
+ SRCS
+ "internal/front_binder.h"
+ HDRS
+ "bind_front.h"
+ COPTS
+ ${ABSL_DEFAULT_COPTS}
+ DEPS
+ absl::base_internal
+ absl::compressed_tuple
+ PUBLIC
+)
+
+absl_cc_test(
+ NAME
+ bind_front_test
+ SRCS
+ "bind_front_test.cc"
+ COPTS
+ ${ABSL_DEFAULT_COPTS}
+ DEPS
+ absl::bind_front
+ absl::memory
+ gmock_main
+)
+
+absl_cc_library(
+ NAME
+ function_ref
+ SRCS
+ "internal/function_ref.h"
+ HDRS
+ "function_ref.h"
+ COPTS
+ ${ABSL_DEFAULT_COPTS}
+ DEPS
+ absl::base_internal
+ absl::meta
+ PUBLIC
+)
+
+absl_cc_test(
+ NAME
+ function_ref_test
+ SRCS
+ "function_ref_test.cc"
+ COPTS
+ ${ABSL_TEST_COPTS}
+ DEPS
+ absl::function_ref
+ absl::memory
+ absl::test_instance_tracker
+ gmock_main
+)
diff --git a/absl/functional/bind_front.h b/absl/functional/bind_front.h
new file mode 100644
index 0000000..5b47970
--- /dev/null
+++ b/absl/functional/bind_front.h
@@ -0,0 +1,184 @@
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// -----------------------------------------------------------------------------
+// File: bind_front.h
+// -----------------------------------------------------------------------------
+//
+// `absl::bind_front()` returns a functor by binding a number of arguments to
+// the front of a provided (usually more generic) functor. Unlike `std::bind`,
+// it does not require the use of argument placeholders. The simpler syntax of
+// `absl::bind_front()` allows you to avoid known misuses with `std::bind()`.
+//
+// `absl::bind_front()` is meant as a drop-in replacement for C++20's upcoming
+// `std::bind_front()`, which similarly resolves these issues with
+// `std::bind()`. Both `bind_front()` alternatives, unlike `std::bind()`, allow
+// partial function application. (See
+// https://en.wikipedia.org/wiki/Partial_application).
+
+#ifndef ABSL_FUNCTIONAL_BIND_FRONT_H_
+#define ABSL_FUNCTIONAL_BIND_FRONT_H_
+
+#include "absl/functional/internal/front_binder.h"
+#include "absl/utility/utility.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+// bind_front()
+//
+// Binds the first N arguments of an invocable object and stores them by value.
+//
+// Like `std::bind()`, `absl::bind_front()` is implicitly convertible to
+// `std::function`. In particular, it may be used as a simpler replacement for
+// `std::bind()` in most cases, as it does not require placeholders to be
+// specified. More importantly, it provides more reliable correctness guarantees
+// than `std::bind()`; while `std::bind()` will silently ignore passing more
+// parameters than expected, for example, `absl::bind_front()` will report such
+// mis-uses as errors.
+//
+// absl::bind_front(a...) can be seen as storing the results of
+// std::make_tuple(a...).
+//
+// Example: Binding a free function.
+//
+// int Minus(int a, int b) { return a - b; }
+//
+// assert(absl::bind_front(Minus)(3, 2) == 3 - 2);
+// assert(absl::bind_front(Minus, 3)(2) == 3 - 2);
+// assert(absl::bind_front(Minus, 3, 2)() == 3 - 2);
+//
+// Example: Binding a member function.
+//
+// struct Math {
+// int Double(int a) const { return 2 * a; }
+// };
+//
+// Math math;
+//
+// assert(absl::bind_front(&Math::Double)(&math, 3) == 2 * 3);
+// // Stores a pointer to math inside the functor.
+// assert(absl::bind_front(&Math::Double, &math)(3) == 2 * 3);
+// // Stores a copy of math inside the functor.
+// assert(absl::bind_front(&Math::Double, math)(3) == 2 * 3);
+// // Stores std::unique_ptr<Math> inside the functor.
+// assert(absl::bind_front(&Math::Double,
+// std::unique_ptr<Math>(new Math))(3) == 2 * 3);
+//
+// Example: Using `absl::bind_front()`, instead of `std::bind()`, with
+// `std::function`.
+//
+// class FileReader {
+// public:
+// void ReadFileAsync(const std::string& filename, std::string* content,
+// const std::function<void()>& done) {
+// // Calls Executor::Schedule(std::function<void()>).
+// Executor::DefaultExecutor()->Schedule(
+// absl::bind_front(&FileReader::BlockingRead, this,
+// filename, content, done));
+// }
+//
+// private:
+// void BlockingRead(const std::string& filename, std::string* content,
+// const std::function<void()>& done) {
+// CHECK_OK(file::GetContents(filename, content, {}));
+// done();
+// }
+// };
+//
+// `absl::bind_front()` stores bound arguments explicitly using the type passed
+// rather than implicitly based on the type accepted by its functor.
+//
+// Example: Binding arguments explicitly.
+//
+// void LogStringView(absl::string_view sv) {
+// LOG(INFO) << sv;
+// }
+//
+// Executor* e = Executor::DefaultExecutor();
+// std::string s = "hello";
+// absl::string_view sv = s;
+//
+// // absl::bind_front(LogStringView, arg) makes a copy of arg and stores it.
+// e->Schedule(absl::bind_front(LogStringView, sv)); // ERROR: dangling
+// // string_view.
+//
+// e->Schedule(absl::bind_front(LogStringView, s)); // OK: stores a copy of
+// // s.
+//
+// To store some of the arguments passed to `absl::bind_front()` by reference,
+// use std::ref()` and `std::cref()`.
+//
+// Example: Storing some of the bound arguments by reference.
+//
+// class Service {
+// public:
+// void Serve(const Request& req, std::function<void()>* done) {
+// // The request protocol buffer won't be deleted until done is called.
+// // It's safe to store a reference to it inside the functor.
+// Executor::DefaultExecutor()->Schedule(
+// absl::bind_front(&Service::BlockingServe, this, std::cref(req),
+// done));
+// }
+//
+// private:
+// void BlockingServe(const Request& req, std::function<void()>* done);
+// };
+//
+// Example: Storing bound arguments by reference.
+//
+// void Print(const std::string& a, const std::string& b) {
+// std::cerr << a << b;
+// }
+//
+// std::string hi = "Hello, ";
+// std::vector<std::string> names = {"Chuk", "Gek"};
+// // Doesn't copy hi.
+// for_each(names.begin(), names.end(),
+// absl::bind_front(Print, std::ref(hi)));
+//
+// // DO NOT DO THIS: the functor may outlive "hi", resulting in
+// // dangling references.
+// foo->DoInFuture(absl::bind_front(Print, std::ref(hi), "Guest")); // BAD!
+// auto f = absl::bind_front(Print, std::ref(hi), "Guest"); // BAD!
+//
+// Example: Storing reference-like types.
+//
+// void Print(absl::string_view a, const std::string& b) {
+// std::cerr << a << b;
+// }
+//
+// std::string hi = "Hello, ";
+// // Copies "hi".
+// absl::bind_front(Print, hi)("Chuk");
+//
+// // Compile error: std::reference_wrapper<const string> is not implicitly
+// // convertible to string_view.
+// // absl::bind_front(Print, std::cref(hi))("Chuk");
+//
+// // Doesn't copy "hi".
+// absl::bind_front(Print, absl::string_view(hi))("Chuk");
+//
+template <class F, class... BoundArgs>
+constexpr functional_internal::bind_front_t<F, BoundArgs...> bind_front(
+ F&& func, BoundArgs&&... args) {
+ return functional_internal::bind_front_t<F, BoundArgs...>(
+ absl::in_place, absl::forward<F>(func),
+ absl::forward<BoundArgs>(args)...);
+}
+
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_FUNCTIONAL_BIND_FRONT_H_
diff --git a/absl/functional/bind_front_test.cc b/absl/functional/bind_front_test.cc
new file mode 100644
index 0000000..4801a81
--- /dev/null
+++ b/absl/functional/bind_front_test.cc
@@ -0,0 +1,231 @@
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/functional/bind_front.h"
+
+#include <stddef.h>
+
+#include <functional>
+#include <memory>
+#include <string>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/memory/memory.h"
+
+namespace {
+
+char CharAt(const char* s, size_t index) { return s[index]; }
+
+TEST(BindTest, Basics) {
+ EXPECT_EQ('C', absl::bind_front(CharAt)("ABC", 2));
+ EXPECT_EQ('C', absl::bind_front(CharAt, "ABC")(2));
+ EXPECT_EQ('C', absl::bind_front(CharAt, "ABC", 2)());
+}
+
+TEST(BindTest, Lambda) {
+ auto lambda = [](int x, int y, int z) { return x + y + z; };
+ EXPECT_EQ(6, absl::bind_front(lambda)(1, 2, 3));
+ EXPECT_EQ(6, absl::bind_front(lambda, 1)(2, 3));
+ EXPECT_EQ(6, absl::bind_front(lambda, 1, 2)(3));
+ EXPECT_EQ(6, absl::bind_front(lambda, 1, 2, 3)());
+}
+
+struct Functor {
+ std::string operator()() & { return "&"; }
+ std::string operator()() const& { return "const&"; }
+ std::string operator()() && { return "&&"; }
+ std::string operator()() const&& { return "const&&"; }
+};
+
+TEST(BindTest, PerfectForwardingOfBoundArgs) {
+ auto f = absl::bind_front(Functor());
+ const auto& cf = f;
+ EXPECT_EQ("&", f());
+ EXPECT_EQ("const&", cf());
+ EXPECT_EQ("&&", std::move(f)());
+ EXPECT_EQ("const&&", std::move(cf)());
+}
+
+struct ArgDescribe {
+ std::string operator()(int&) const { return "&"; } // NOLINT
+ std::string operator()(const int&) const { return "const&"; } // NOLINT
+ std::string operator()(int&&) const { return "&&"; }
+ std::string operator()(const int&&) const { return "const&&"; }
+};
+
+TEST(BindTest, PerfectForwardingOfFreeArgs) {
+ ArgDescribe f;
+ int i;
+ EXPECT_EQ("&", absl::bind_front(f)(static_cast<int&>(i)));
+ EXPECT_EQ("const&", absl::bind_front(f)(static_cast<const int&>(i)));
+ EXPECT_EQ("&&", absl::bind_front(f)(static_cast<int&&>(i)));
+ EXPECT_EQ("const&&", absl::bind_front(f)(static_cast<const int&&>(i)));
+}
+
+struct NonCopyableFunctor {
+ NonCopyableFunctor() = default;
+ NonCopyableFunctor(const NonCopyableFunctor&) = delete;
+ NonCopyableFunctor& operator=(const NonCopyableFunctor&) = delete;
+ const NonCopyableFunctor* operator()() const { return this; }
+};
+
+TEST(BindTest, RefToFunctor) {
+ // It won't copy/move the functor and use the original object.
+ NonCopyableFunctor ncf;
+ auto bound_ncf = absl::bind_front(std::ref(ncf));
+ auto bound_ncf_copy = bound_ncf;
+ EXPECT_EQ(&ncf, bound_ncf_copy());
+}
+
+struct Struct {
+ std::string value;
+};
+
+TEST(BindTest, StoreByCopy) {
+ Struct s = {"hello"};
+ auto f = absl::bind_front(&Struct::value, s);
+ auto g = f;
+ EXPECT_EQ("hello", f());
+ EXPECT_EQ("hello", g());
+ EXPECT_NE(&s.value, &f());
+ EXPECT_NE(&s.value, &g());
+ EXPECT_NE(&g(), &f());
+}
+
+struct NonCopyable {
+ explicit NonCopyable(const std::string& s) : value(s) {}
+ NonCopyable(const NonCopyable&) = delete;
+ NonCopyable& operator=(const NonCopyable&) = delete;
+
+ std::string value;
+};
+
+const std::string& GetNonCopyableValue(const NonCopyable& n) { return n.value; }
+
+TEST(BindTest, StoreByRef) {
+ NonCopyable s("hello");
+ auto f = absl::bind_front(&GetNonCopyableValue, std::ref(s));
+ EXPECT_EQ("hello", f());
+ EXPECT_EQ(&s.value, &f());
+ auto g = std::move(f); // NOLINT
+ EXPECT_EQ("hello", g());
+ EXPECT_EQ(&s.value, &g());
+ s.value = "goodbye";
+ EXPECT_EQ("goodbye", g());
+}
+
+TEST(BindTest, StoreByCRef) {
+ NonCopyable s("hello");
+ auto f = absl::bind_front(&GetNonCopyableValue, std::cref(s));
+ EXPECT_EQ("hello", f());
+ EXPECT_EQ(&s.value, &f());
+ auto g = std::move(f); // NOLINT
+ EXPECT_EQ("hello", g());
+ EXPECT_EQ(&s.value, &g());
+ s.value = "goodbye";
+ EXPECT_EQ("goodbye", g());
+}
+
+const std::string& GetNonCopyableValueByWrapper(
+ std::reference_wrapper<NonCopyable> n) {
+ return n.get().value;
+}
+
+TEST(BindTest, StoreByRefInvokeByWrapper) {
+ NonCopyable s("hello");
+ auto f = absl::bind_front(GetNonCopyableValueByWrapper, std::ref(s));
+ EXPECT_EQ("hello", f());
+ EXPECT_EQ(&s.value, &f());
+ auto g = std::move(f);
+ EXPECT_EQ("hello", g());
+ EXPECT_EQ(&s.value, &g());
+ s.value = "goodbye";
+ EXPECT_EQ("goodbye", g());
+}
+
+TEST(BindTest, StoreByPointer) {
+ NonCopyable s("hello");
+ auto f = absl::bind_front(&NonCopyable::value, &s);
+ EXPECT_EQ("hello", f());
+ EXPECT_EQ(&s.value, &f());
+ auto g = std::move(f);
+ EXPECT_EQ("hello", g());
+ EXPECT_EQ(&s.value, &g());
+}
+
+int Sink(std::unique_ptr<int> p) {
+ return *p;
+}
+
+std::unique_ptr<int> Factory(int n) { return absl::make_unique<int>(n); }
+
+TEST(BindTest, NonCopyableArg) {
+ EXPECT_EQ(42, absl::bind_front(Sink)(absl::make_unique<int>(42)));
+ EXPECT_EQ(42, absl::bind_front(Sink, absl::make_unique<int>(42))());
+}
+
+TEST(BindTest, NonCopyableResult) {
+ EXPECT_THAT(absl::bind_front(Factory)(42), ::testing::Pointee(42));
+ EXPECT_THAT(absl::bind_front(Factory, 42)(), ::testing::Pointee(42));
+}
+
+// is_copy_constructible<FalseCopyable<unique_ptr<T>> is true but an attempt to
+// instantiate the copy constructor leads to a compile error. This is similar
+// to how standard containers behave.
+template <class T>
+struct FalseCopyable {
+ FalseCopyable() {}
+ FalseCopyable(const FalseCopyable& other) : m(other.m) {}
+ FalseCopyable(FalseCopyable&& other) : m(std::move(other.m)) {}
+ T m;
+};
+
+int GetMember(FalseCopyable<std::unique_ptr<int>> x) { return *x.m; }
+
+TEST(BindTest, WrappedMoveOnly) {
+ FalseCopyable<std::unique_ptr<int>> x;
+ x.m = absl::make_unique<int>(42);
+ auto f = absl::bind_front(&GetMember, std::move(x));
+ EXPECT_EQ(42, std::move(f)());
+}
+
+int Plus(int a, int b) { return a + b; }
+
+TEST(BindTest, ConstExpr) {
+ constexpr auto f = absl::bind_front(CharAt);
+ EXPECT_EQ(f("ABC", 1), 'B');
+ static constexpr int five = 5;
+ constexpr auto plus5 = absl::bind_front(Plus, five);
+ EXPECT_EQ(plus5(1), 6);
+
+ // There seems to be a bug in MSVC dealing constexpr construction of
+ // char[]. Notice 'plus5' above; 'int' works just fine.
+#if !(defined(_MSC_VER) && _MSC_VER < 1910)
+ static constexpr char data[] = "DEF";
+ constexpr auto g = absl::bind_front(CharAt, data);
+ EXPECT_EQ(g(1), 'E');
+#endif
+}
+
+struct ManglingCall {
+ int operator()(int, double, std::string) const { return 0; }
+};
+
+TEST(BindTest, Mangling) {
+ // We just want to generate a particular instantiation to see its mangling.
+ absl::bind_front(ManglingCall{}, 1, 3.3)("A");
+}
+
+} // namespace
diff --git a/absl/functional/function_ref.h b/absl/functional/function_ref.h
new file mode 100644
index 0000000..6e03ac2
--- /dev/null
+++ b/absl/functional/function_ref.h
@@ -0,0 +1,139 @@
+// Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// -----------------------------------------------------------------------------
+// File: function_ref.h
+// -----------------------------------------------------------------------------
+//
+// This header file defines the `absl::FunctionRef` type for holding a
+// non-owning reference to an object of any invocable type. This function
+// reference is typically most useful as a type-erased argument type for
+// accepting function types that neither take ownership nor copy the type; using
+// the reference type in this case avoids a copy and an allocation. Best
+// practices of other non-owning reference-like objects (such as
+// `absl::string_view`) apply here.
+//
+// An `absl::FunctionRef` is similar in usage to a `std::function` but has the
+// following differences:
+//
+// * It doesn't own the underlying object.
+// * It doesn't have a null or empty state.
+// * It never performs deep copies or allocations.
+// * It's much faster and cheaper to construct.
+// * It's trivially copyable and destructable.
+//
+// Generally, `absl::FunctionRef` should not be used as a return value, data
+// member, or to initialize a `std::function`. Such usages will often lead to
+// problematic lifetime issues. Once you convert something to an
+// `absl::FunctionRef` you cannot make a deep copy later.
+//
+// This class is suitable for use wherever a "const std::function<>&"
+// would be used without making a copy. ForEach functions and other versions of
+// the visitor pattern are a good example of when this class should be used.
+//
+// This class is trivial to copy and should be passed by value.
+#ifndef ABSL_FUNCTIONAL_FUNCTION_REF_H_
+#define ABSL_FUNCTIONAL_FUNCTION_REF_H_
+
+#include <cassert>
+#include <functional>
+#include <type_traits>
+
+#include "absl/functional/internal/function_ref.h"
+#include "absl/meta/type_traits.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+// FunctionRef
+//
+// Dummy class declaration to allow the partial specialization based on function
+// types below.
+template <typename T>
+class FunctionRef;
+
+// FunctionRef
+//
+// An `absl::FunctionRef` is a lightweight wrapper to any invokable object with
+// a compatible signature. Generally, an `absl::FunctionRef` should only be used
+// as an argument type and should be preferred as an argument over a const
+// reference to a `std::function`.
+//
+// Example:
+//
+// // The following function takes a function callback by const reference
+// bool Visitor(const std::function<void(my_proto&,
+// absl::string_view)>& callback);
+//
+// // Assuming that the function is not stored or otherwise copied, it can be
+// // replaced by an `absl::FunctionRef`:
+// bool Visitor(absl::FunctionRef<void(my_proto&, absl::string_view)>
+// callback);
+//
+// Note: the assignment operator within an `absl::FunctionRef` is intentionally
+// deleted to prevent misuse; because the `absl::FunctionRef` does not own the
+// underlying type, assignment likely indicates misuse.
+template <typename R, typename... Args>
+class FunctionRef<R(Args...)> {
+ private:
+ // Used to disable constructors for objects that are not compatible with the
+ // signature of this FunctionRef.
+ template <typename F,
+ typename FR = absl::base_internal::invoke_result_t<F, Args&&...>>
+ using EnableIfCompatible =
+ typename std::enable_if<std::is_void<R>::value ||
+ std::is_convertible<FR, R>::value>::type;
+
+ public:
+ // Constructs a FunctionRef from any invokable type.
+ template <typename F, typename = EnableIfCompatible<const F&>>
+ FunctionRef(const F& f) // NOLINT(runtime/explicit)
+ : invoker_(&absl::functional_internal::InvokeObject<F, R, Args...>) {
+ absl::functional_internal::AssertNonNull(f);
+ ptr_.obj = &f;
+ }
+
+ // Overload for function pointers. This eliminates a level of indirection that
+ // would happen if the above overload was used (it lets us store the pointer
+ // instead of a pointer to a pointer).
+ //
+ // This overload is also used for references to functions, since references to
+ // functions can decay to function pointers implicitly.
+ template <
+ typename F, typename = EnableIfCompatible<F*>,
+ absl::functional_internal::EnableIf<absl::is_function<F>::value> = 0>
+ FunctionRef(F* f) // NOLINT(runtime/explicit)
+ : invoker_(&absl::functional_internal::InvokeFunction<F*, R, Args...>) {
+ assert(f != nullptr);
+ ptr_.fun = reinterpret_cast<decltype(ptr_.fun)>(f);
+ }
+
+ // To help prevent subtle lifetime bugs, FunctionRef is not assignable.
+ // Typically, it should only be used as an argument type.
+ FunctionRef& operator=(const FunctionRef& rhs) = delete;
+
+ // Call the underlying object.
+ R operator()(Args... args) const {
+ return invoker_(ptr_, std::forward<Args>(args)...);
+ }
+
+ private:
+ absl::functional_internal::VoidPtr ptr_;
+ absl::functional_internal::Invoker<R, Args...> invoker_;
+};
+
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_FUNCTIONAL_FUNCTION_REF_H_
diff --git a/absl/functional/function_ref_benchmark.cc b/absl/functional/function_ref_benchmark.cc
new file mode 100644
index 0000000..045305b
--- /dev/null
+++ b/absl/functional/function_ref_benchmark.cc
@@ -0,0 +1,142 @@
+// Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/functional/function_ref.h"
+
+#include <memory>
+
+#include "benchmark/benchmark.h"
+#include "absl/base/attributes.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace {
+
+int dummy = 0;
+
+void FreeFunction() { benchmark::DoNotOptimize(dummy); }
+
+struct TrivialFunctor {
+ void operator()() const { benchmark::DoNotOptimize(dummy); }
+};
+
+struct LargeFunctor {
+ void operator()() const { benchmark::DoNotOptimize(this); }
+ std::string a, b, c;
+};
+
+template <typename Function, typename... Args>
+void ABSL_ATTRIBUTE_NOINLINE CallFunction(Function f, Args&&... args) {
+ f(std::forward<Args>(args)...);
+}
+
+template <typename Function, typename Callable, typename... Args>
+void ConstructAndCallFunctionBenchmark(benchmark::State& state,
+ const Callable& c, Args&&... args) {
+ for (auto _ : state) {
+ CallFunction<Function>(c, std::forward<Args>(args)...);
+ }
+}
+
+void BM_TrivialStdFunction(benchmark::State& state) {
+ ConstructAndCallFunctionBenchmark<std::function<void()>>(state,
+ TrivialFunctor{});
+}
+BENCHMARK(BM_TrivialStdFunction);
+
+void BM_TrivialFunctionRef(benchmark::State& state) {
+ ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state,
+ TrivialFunctor{});
+}
+BENCHMARK(BM_TrivialFunctionRef);
+
+void BM_LargeStdFunction(benchmark::State& state) {
+ ConstructAndCallFunctionBenchmark<std::function<void()>>(state,
+ LargeFunctor{});
+}
+BENCHMARK(BM_LargeStdFunction);
+
+void BM_LargeFunctionRef(benchmark::State& state) {
+ ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state, LargeFunctor{});
+}
+BENCHMARK(BM_LargeFunctionRef);
+
+void BM_FunPtrStdFunction(benchmark::State& state) {
+ ConstructAndCallFunctionBenchmark<std::function<void()>>(state, FreeFunction);
+}
+BENCHMARK(BM_FunPtrStdFunction);
+
+void BM_FunPtrFunctionRef(benchmark::State& state) {
+ ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state, FreeFunction);
+}
+BENCHMARK(BM_FunPtrFunctionRef);
+
+// Doesn't include construction or copy overhead in the loop.
+template <typename Function, typename Callable, typename... Args>
+void CallFunctionBenchmark(benchmark::State& state, const Callable& c,
+ Args... args) {
+ Function f = c;
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(&f);
+ f(args...);
+ }
+}
+
+struct FunctorWithTrivialArgs {
+ void operator()(int a, int b, int c) const {
+ benchmark::DoNotOptimize(a);
+ benchmark::DoNotOptimize(b);
+ benchmark::DoNotOptimize(c);
+ }
+};
+
+void BM_TrivialArgsStdFunction(benchmark::State& state) {
+ CallFunctionBenchmark<std::function<void(int, int, int)>>(
+ state, FunctorWithTrivialArgs{}, 1, 2, 3);
+}
+BENCHMARK(BM_TrivialArgsStdFunction);
+
+void BM_TrivialArgsFunctionRef(benchmark::State& state) {
+ CallFunctionBenchmark<FunctionRef<void(int, int, int)>>(
+ state, FunctorWithTrivialArgs{}, 1, 2, 3);
+}
+BENCHMARK(BM_TrivialArgsFunctionRef);
+
+struct FunctorWithNonTrivialArgs {
+ void operator()(std::string a, std::string b, std::string c) const {
+ benchmark::DoNotOptimize(&a);
+ benchmark::DoNotOptimize(&b);
+ benchmark::DoNotOptimize(&c);
+ }
+};
+
+void BM_NonTrivialArgsStdFunction(benchmark::State& state) {
+ std::string a, b, c;
+ CallFunctionBenchmark<
+ std::function<void(std::string, std::string, std::string)>>(
+ state, FunctorWithNonTrivialArgs{}, a, b, c);
+}
+BENCHMARK(BM_NonTrivialArgsStdFunction);
+
+void BM_NonTrivialArgsFunctionRef(benchmark::State& state) {
+ std::string a, b, c;
+ CallFunctionBenchmark<
+ FunctionRef<void(std::string, std::string, std::string)>>(
+ state, FunctorWithNonTrivialArgs{}, a, b, c);
+}
+BENCHMARK(BM_NonTrivialArgsFunctionRef);
+
+} // namespace
+ABSL_NAMESPACE_END
+} // namespace absl
diff --git a/absl/functional/function_ref_test.cc b/absl/functional/function_ref_test.cc
new file mode 100644
index 0000000..3aa5974
--- /dev/null
+++ b/absl/functional/function_ref_test.cc
@@ -0,0 +1,257 @@
+// Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/functional/function_ref.h"
+
+#include <memory>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/container/internal/test_instance_tracker.h"
+#include "absl/memory/memory.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace {
+
+void RunFun(FunctionRef<void()> f) { f(); }
+
+TEST(FunctionRefTest, Lambda) {
+ bool ran = false;
+ RunFun([&] { ran = true; });
+ EXPECT_TRUE(ran);
+}
+
+int Function() { return 1337; }
+
+TEST(FunctionRefTest, Function1) {
+ FunctionRef<int()> ref(&Function);
+ EXPECT_EQ(1337, ref());
+}
+
+TEST(FunctionRefTest, Function2) {
+ FunctionRef<int()> ref(Function);
+ EXPECT_EQ(1337, ref());
+}
+
+int NoExceptFunction() noexcept { return 1337; }
+
+// TODO(jdennett): Add a test for noexcept member functions.
+TEST(FunctionRefTest, NoExceptFunction) {
+ FunctionRef<int()> ref(NoExceptFunction);
+ EXPECT_EQ(1337, ref());
+}
+
+TEST(FunctionRefTest, ForwardsArgs) {
+ auto l = [](std::unique_ptr<int> i) { return *i; };
+ FunctionRef<int(std::unique_ptr<int>)> ref(l);
+ EXPECT_EQ(42, ref(absl::make_unique<int>(42)));
+}
+
+TEST(FunctionRef, ReturnMoveOnly) {
+ auto l = [] { return absl::make_unique<int>(29); };
+ FunctionRef<std::unique_ptr<int>()> ref(l);
+ EXPECT_EQ(29, *ref());
+}
+
+TEST(FunctionRef, ManyArgs) {
+ auto l = [](int a, int b, int c) { return a + b + c; };
+ FunctionRef<int(int, int, int)> ref(l);
+ EXPECT_EQ(6, ref(1, 2, 3));
+}
+
+TEST(FunctionRef, VoidResultFromNonVoidFunctor) {
+ bool ran = false;
+ auto l = [&]() -> int {
+ ran = true;
+ return 2;
+ };
+ FunctionRef<void()> ref(l);
+ ref();
+ EXPECT_TRUE(ran);
+}
+
+TEST(FunctionRef, CastFromDerived) {
+ struct Base {};
+ struct Derived : public Base {};
+
+ Derived d;
+ auto l1 = [&](Base* b) { EXPECT_EQ(&d, b); };
+ FunctionRef<void(Derived*)> ref1(l1);
+ ref1(&d);
+
+ auto l2 = [&]() -> Derived* { return &d; };
+ FunctionRef<Base*()> ref2(l2);
+ EXPECT_EQ(&d, ref2());
+}
+
+TEST(FunctionRef, VoidResultFromNonVoidFuncton) {
+ FunctionRef<void()> ref(Function);
+ ref();
+}
+
+TEST(FunctionRef, MemberPtr) {
+ struct S {
+ int i;
+ };
+
+ S s{1100111};
+ auto mem_ptr = &S::i;
+ FunctionRef<int(const S& s)> ref(mem_ptr);
+ EXPECT_EQ(1100111, ref(s));
+}
+
+TEST(FunctionRef, MemberFun) {
+ struct S {
+ int i;
+ int get_i() const { return i; }
+ };
+
+ S s{22};
+ auto mem_fun_ptr = &S::get_i;
+ FunctionRef<int(const S& s)> ref(mem_fun_ptr);
+ EXPECT_EQ(22, ref(s));
+}
+
+TEST(FunctionRef, MemberFunRefqualified) {
+ struct S {
+ int i;
+ int get_i() && { return i; }
+ };
+ auto mem_fun_ptr = &S::get_i;
+ S s{22};
+ FunctionRef<int(S && s)> ref(mem_fun_ptr);
+ EXPECT_EQ(22, ref(std::move(s)));
+}
+
+#if !defined(_WIN32) && defined(GTEST_HAS_DEATH_TEST)
+
+TEST(FunctionRef, MemberFunRefqualifiedNull) {
+ struct S {
+ int i;
+ int get_i() && { return i; }
+ };
+ auto mem_fun_ptr = &S::get_i;
+ mem_fun_ptr = nullptr;
+ EXPECT_DEBUG_DEATH({ FunctionRef<int(S && s)> ref(mem_fun_ptr); }, "");
+}
+
+TEST(FunctionRef, NullMemberPtrAssertFails) {
+ struct S {
+ int i;
+ };
+ using MemberPtr = int S::*;
+ MemberPtr mem_ptr = nullptr;
+ EXPECT_DEBUG_DEATH({ FunctionRef<int(const S& s)> ref(mem_ptr); }, "");
+}
+
+#endif // GTEST_HAS_DEATH_TEST
+
+TEST(FunctionRef, CopiesAndMovesPerPassByValue) {
+ absl::test_internal::InstanceTracker tracker;
+ absl::test_internal::CopyableMovableInstance instance(0);
+ auto l = [](absl::test_internal::CopyableMovableInstance) {};
+ FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
+ ref(instance);
+ EXPECT_EQ(tracker.copies(), 1);
+ EXPECT_EQ(tracker.moves(), 1);
+}
+
+TEST(FunctionRef, CopiesAndMovesPerPassByRef) {
+ absl::test_internal::InstanceTracker tracker;
+ absl::test_internal::CopyableMovableInstance instance(0);
+ auto l = [](const absl::test_internal::CopyableMovableInstance&) {};
+ FunctionRef<void(const absl::test_internal::CopyableMovableInstance&)> ref(l);
+ ref(instance);
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 0);
+}
+
+TEST(FunctionRef, CopiesAndMovesPerPassByValueCallByMove) {
+ absl::test_internal::InstanceTracker tracker;
+ absl::test_internal::CopyableMovableInstance instance(0);
+ auto l = [](absl::test_internal::CopyableMovableInstance) {};
+ FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
+ ref(std::move(instance));
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 2);
+}
+
+TEST(FunctionRef, CopiesAndMovesPerPassByValueToRef) {
+ absl::test_internal::InstanceTracker tracker;
+ absl::test_internal::CopyableMovableInstance instance(0);
+ auto l = [](const absl::test_internal::CopyableMovableInstance&) {};
+ FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
+ ref(std::move(instance));
+ EXPECT_EQ(tracker.copies(), 0);
+ EXPECT_EQ(tracker.moves(), 1);
+}
+
+TEST(FunctionRef, PassByValueTypes) {
+ using absl::functional_internal::Invoker;
+ using absl::functional_internal::VoidPtr;
+ using absl::test_internal::CopyableMovableInstance;
+ struct Trivial {
+ void* p[2];
+ };
+ struct LargeTrivial {
+ void* p[3];
+ };
+
+ static_assert(std::is_same<Invoker<void, int>, void (*)(VoidPtr, int)>::value,
+ "Scalar types should be passed by value");
+ static_assert(
+ std::is_same<Invoker<void, Trivial>, void (*)(VoidPtr, Trivial)>::value,
+ "Small trivial types should be passed by value");
+ static_assert(std::is_same<Invoker<void, LargeTrivial>,
+ void (*)(VoidPtr, LargeTrivial &&)>::value,
+ "Large trivial types should be passed by rvalue reference");
+ static_assert(
+ std::is_same<Invoker<void, CopyableMovableInstance>,
+ void (*)(VoidPtr, CopyableMovableInstance &&)>::value,
+ "Types with copy/move ctor should be passed by rvalue reference");
+
+ // References are passed as references.
+ static_assert(
+ std::is_same<Invoker<void, int&>, void (*)(VoidPtr, int&)>::value,
+ "Reference types should be preserved");
+ static_assert(
+ std::is_same<Invoker<void, CopyableMovableInstance&>,
+ void (*)(VoidPtr, CopyableMovableInstance&)>::value,
+ "Reference types should be preserved");
+ static_assert(
+ std::is_same<Invoker<void, CopyableMovableInstance&&>,
+ void (*)(VoidPtr, CopyableMovableInstance &&)>::value,
+ "Reference types should be preserved");
+
+ // Make sure the address of an object received by reference is the same as the
+ // addess of the object passed by the caller.
+ {
+ LargeTrivial obj;
+ auto test = [&obj](LargeTrivial& input) { ASSERT_EQ(&input, &obj); };
+ absl::FunctionRef<void(LargeTrivial&)> ref(test);
+ ref(obj);
+ }
+
+ {
+ Trivial obj;
+ auto test = [&obj](Trivial& input) { ASSERT_EQ(&input, &obj); };
+ absl::FunctionRef<void(Trivial&)> ref(test);
+ ref(obj);
+ }
+}
+
+} // namespace
+ABSL_NAMESPACE_END
+} // namespace absl
diff --git a/absl/functional/internal/front_binder.h b/absl/functional/internal/front_binder.h
new file mode 100644
index 0000000..45f52de
--- /dev/null
+++ b/absl/functional/internal/front_binder.h
@@ -0,0 +1,95 @@
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Implementation details for `absl::bind_front()`.
+
+#ifndef ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_
+#define ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_
+
+#include <cstddef>
+#include <type_traits>
+#include <utility>
+
+#include "absl/base/internal/invoke.h"
+#include "absl/container/internal/compressed_tuple.h"
+#include "absl/meta/type_traits.h"
+#include "absl/utility/utility.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace functional_internal {
+
+// Invoke the method, expanding the tuple of bound arguments.
+template <class R, class Tuple, size_t... Idx, class... Args>
+R Apply(Tuple&& bound, absl::index_sequence<Idx...>, Args&&... free) {
+ return base_internal::invoke(
+ absl::forward<Tuple>(bound).template get<Idx>()...,
+ absl::forward<Args>(free)...);
+}
+
+template <class F, class... BoundArgs>
+class FrontBinder {
+ using BoundArgsT = absl::container_internal::CompressedTuple<F, BoundArgs...>;
+ using Idx = absl::make_index_sequence<sizeof...(BoundArgs) + 1>;
+
+ BoundArgsT bound_args_;
+
+ public:
+ template <class... Ts>
+ constexpr explicit FrontBinder(absl::in_place_t, Ts&&... ts)
+ : bound_args_(absl::forward<Ts>(ts)...) {}
+
+ template <class... FreeArgs, class R = base_internal::invoke_result_t<
+ F&, BoundArgs&..., FreeArgs&&...>>
+ R operator()(FreeArgs&&... free_args) & {
+ return functional_internal::Apply<R>(bound_args_, Idx(),
+ absl::forward<FreeArgs>(free_args)...);
+ }
+
+ template <class... FreeArgs,
+ class R = base_internal::invoke_result_t<
+ const F&, const BoundArgs&..., FreeArgs&&...>>
+ R operator()(FreeArgs&&... free_args) const& {
+ return functional_internal::Apply<R>(bound_args_, Idx(),
+ absl::forward<FreeArgs>(free_args)...);
+ }
+
+ template <class... FreeArgs, class R = base_internal::invoke_result_t<
+ F&&, BoundArgs&&..., FreeArgs&&...>>
+ R operator()(FreeArgs&&... free_args) && {
+ // This overload is called when *this is an rvalue. If some of the bound
+ // arguments are stored by value or rvalue reference, we move them.
+ return functional_internal::Apply<R>(absl::move(bound_args_), Idx(),
+ absl::forward<FreeArgs>(free_args)...);
+ }
+
+ template <class... FreeArgs,
+ class R = base_internal::invoke_result_t<
+ const F&&, const BoundArgs&&..., FreeArgs&&...>>
+ R operator()(FreeArgs&&... free_args) const&& {
+ // This overload is called when *this is an rvalue. If some of the bound
+ // arguments are stored by value or rvalue reference, we move them.
+ return functional_internal::Apply<R>(absl::move(bound_args_), Idx(),
+ absl::forward<FreeArgs>(free_args)...);
+ }
+};
+
+template <class F, class... BoundArgs>
+using bind_front_t = FrontBinder<decay_t<F>, absl::decay_t<BoundArgs>...>;
+
+} // namespace functional_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_
diff --git a/absl/functional/internal/function_ref.h b/absl/functional/internal/function_ref.h
new file mode 100644
index 0000000..b5bb8b4
--- /dev/null
+++ b/absl/functional/internal/function_ref.h
@@ -0,0 +1,106 @@
+// Copyright 2019 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_
+#define ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_
+
+#include <cassert>
+#include <functional>
+#include <type_traits>
+
+#include "absl/base/internal/invoke.h"
+#include "absl/meta/type_traits.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace functional_internal {
+
+// Like a void* that can handle function pointers as well. The standard does not
+// allow function pointers to round-trip through void*, but void(*)() is fine.
+//
+// Note: It's important that this class remains trivial and is the same size as
+// a pointer, since this allows the compiler to perform tail-call optimizations
+// when the underlying function is a callable object with a matching signature.
+union VoidPtr {
+ const void* obj;
+ void (*fun)();
+};
+
+// Chooses the best type for passing T as an argument.
+// Attempt to be close to SystemV AMD64 ABI. Objects with trivial copy ctor are
+// passed by value.
+template <typename T>
+constexpr bool PassByValue() {
+ return !std::is_lvalue_reference<T>::value &&
+ absl::is_trivially_copy_constructible<T>::value &&
+ absl::is_trivially_copy_assignable<
+ typename std::remove_cv<T>::type>::value &&
+ std::is_trivially_destructible<T>::value &&
+ sizeof(T) <= 2 * sizeof(void*);
+}
+
+template <typename T>
+struct ForwardT : std::conditional<PassByValue<T>(), T, T&&> {};
+
+// An Invoker takes a pointer to the type-erased invokable object, followed by
+// the arguments that the invokable object expects.
+//
+// Note: The order of arguments here is an optimization, since member functions
+// have an implicit "this" pointer as their first argument, putting VoidPtr
+// first allows the compiler to perform tail-call optimization in many cases.
+template <typename R, typename... Args>
+using Invoker = R (*)(VoidPtr, typename ForwardT<Args>::type...);
+
+//
+// InvokeObject and InvokeFunction provide static "Invoke" functions that can be
+// used as Invokers for objects or functions respectively.
+//
+// static_cast<R> handles the case the return type is void.
+template <typename Obj, typename R, typename... Args>
+R InvokeObject(VoidPtr ptr, typename ForwardT<Args>::type... args) {
+ auto o = static_cast<const Obj*>(ptr.obj);
+ return static_cast<R>(
+ absl::base_internal::invoke(*o, std::forward<Args>(args)...));
+}
+
+template <typename Fun, typename R, typename... Args>
+R InvokeFunction(VoidPtr ptr, typename ForwardT<Args>::type... args) {
+ auto f = reinterpret_cast<Fun>(ptr.fun);
+ return static_cast<R>(
+ absl::base_internal::invoke(f, std::forward<Args>(args)...));
+}
+
+template <typename Sig>
+void AssertNonNull(const std::function<Sig>& f) {
+ assert(f != nullptr);
+ (void)f;
+}
+
+template <typename F>
+void AssertNonNull(const F&) {}
+
+template <typename F, typename C>
+void AssertNonNull(F C::*f) {
+ assert(f != nullptr);
+ (void)f;
+}
+
+template <bool C>
+using EnableIf = typename ::std::enable_if<C, int>::type;
+
+} // namespace functional_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_