forked from OSchip/llvm-project
90 lines
3.2 KiB
C++
90 lines
3.2 KiB
C++
//===--- Function.h - Utility callable wrappers -----------------*- C++-*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file provides utilities for callable objects.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_FUNCTION_H
|
|
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_FUNCTION_H
|
|
|
|
#include "llvm/ADT/FunctionExtras.h"
|
|
#include "llvm/Support/Error.h"
|
|
#include <tuple>
|
|
#include <utility>
|
|
|
|
namespace clang {
|
|
namespace clangd {
|
|
|
|
/// A Callback<T> is a void function that accepts Expected<T>.
|
|
/// This is accepted by ClangdServer functions that logically return T.
|
|
template <typename T>
|
|
using Callback = llvm::unique_function<void(llvm::Expected<T>)>;
|
|
|
|
/// Stores a callable object (Func) and arguments (Args) and allows to call the
|
|
/// callable with provided arguments later using `operator ()`. The arguments
|
|
/// are std::forward'ed into the callable in the body of `operator()`. Therefore
|
|
/// `operator()` can only be called once, as some of the arguments could be
|
|
/// std::move'ed into the callable on first call.
|
|
template <class Func, class... Args> struct ForwardBinder {
|
|
using Tuple = std::tuple<typename std::decay<Func>::type,
|
|
typename std::decay<Args>::type...>;
|
|
Tuple FuncWithArguments;
|
|
#ifndef NDEBUG
|
|
bool WasCalled = false;
|
|
#endif
|
|
|
|
public:
|
|
ForwardBinder(Tuple FuncWithArguments)
|
|
: FuncWithArguments(std::move(FuncWithArguments)) {}
|
|
|
|
private:
|
|
template <std::size_t... Indexes, class... RestArgs>
|
|
auto CallImpl(llvm::integer_sequence<std::size_t, Indexes...> Seq,
|
|
RestArgs &&... Rest)
|
|
-> decltype(std::get<0>(this->FuncWithArguments)(
|
|
std::forward<Args>(std::get<Indexes + 1>(this->FuncWithArguments))...,
|
|
std::forward<RestArgs>(Rest)...)) {
|
|
return std::get<0>(this->FuncWithArguments)(
|
|
std::forward<Args>(std::get<Indexes + 1>(this->FuncWithArguments))...,
|
|
std::forward<RestArgs>(Rest)...);
|
|
}
|
|
|
|
public:
|
|
template <class... RestArgs>
|
|
auto operator()(RestArgs &&... Rest)
|
|
-> decltype(this->CallImpl(llvm::index_sequence_for<Args...>(),
|
|
std::forward<RestArgs>(Rest)...)) {
|
|
|
|
#ifndef NDEBUG
|
|
assert(!WasCalled && "Can only call result of Bind once.");
|
|
WasCalled = true;
|
|
#endif
|
|
return CallImpl(llvm::index_sequence_for<Args...>(),
|
|
std::forward<RestArgs>(Rest)...);
|
|
}
|
|
};
|
|
|
|
/// Creates an object that stores a callable (\p F) and first arguments to the
|
|
/// callable (\p As) and allows to call \p F with \Args at a later point.
|
|
/// Similar to std::bind, but also works with move-only \p F and \p As.
|
|
///
|
|
/// The returned object must be called no more than once, as \p As are
|
|
/// std::forwarded'ed (therefore can be moved) into \p F during the call.
|
|
template <class Func, class... Args>
|
|
ForwardBinder<Func, Args...> Bind(Func F, Args &&... As) {
|
|
return ForwardBinder<Func, Args...>(
|
|
std::make_tuple(std::forward<Func>(F), std::forward<Args>(As)...));
|
|
}
|
|
|
|
} // namespace clangd
|
|
} // namespace clang
|
|
|
|
#endif
|