1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
//===--- 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 an analogue to std::function that supports move semantics.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_FUNCTION_H
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_FUNCTION_H
#include <tuple>
#include <type_traits>
#include <utility>
namespace clang {
namespace clangd {
/// A move-only type-erasing function wrapper. Similar to `std::function`, but
/// allows to store move-only callables.
template <class> class UniqueFunction;
template <class Ret, class... Args> class UniqueFunction<Ret(Args...)> {
public:
UniqueFunction() = default;
UniqueFunction(std::nullptr_t) : UniqueFunction(){};
UniqueFunction(UniqueFunction const &) = delete;
UniqueFunction &operator=(UniqueFunction const &) = delete;
UniqueFunction(UniqueFunction &&) noexcept = default;
UniqueFunction &operator=(UniqueFunction &&) noexcept = default;
template <class Callable>
UniqueFunction(Callable &&Func)
: CallablePtr(llvm::make_unique<
FunctionCallImpl<typename std::decay<Callable>::type>>(
std::forward<Callable>(Func))) {}
operator bool() { return CallablePtr; }
Ret operator()(Args... As) {
assert(CallablePtr);
return CallablePtr->Call(std::forward<Args>(As)...);
}
private:
class FunctionCallBase {
public:
virtual ~FunctionCallBase() = default;
virtual Ret Call(Args... As) = 0;
};
template <class Callable>
class FunctionCallImpl final : public FunctionCallBase {
static_assert(
std::is_same<Callable, typename std::decay<Callable>::type>::value,
"FunctionCallImpl must be instanstiated with std::decay'ed types");
public:
FunctionCallImpl(Callable Func) : Func(std::move(Func)) {}
Ret Call(Args... As) override { return Func(std::forward<Args>(As)...); }
private:
Callable Func;
};
std::unique_ptr<FunctionCallBase> CallablePtr;
};
/// 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 BindWithForward 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...> BindWithForward(Func F, Args &&... As) {
return ForwardBinder<Func, Args...>(
std::make_tuple(std::forward<Func>(F), std::forward<Args>(As)...));
}
} // namespace clangd
} // namespace clang
#endif
|
