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Diffstat (limited to 'third_party/abseil_cpp/absl/functional/bind_front.h')
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diff --git a/third_party/abseil_cpp/absl/functional/bind_front.h b/third_party/abseil_cpp/absl/functional/bind_front.h deleted file mode 100644 index 5b47970e35..0000000000 --- a/third_party/abseil_cpp/absl/functional/bind_front.h +++ /dev/null @@ -1,184 +0,0 @@ -// 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_ |