wxhelper-new/inc/spdlog/fmt/bundled/args.h
2024-06-16 13:17:24 +08:00

235 lines
7.2 KiB
C++

// Formatting library for C++ - dynamic format arguments
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.
#ifndef FMT_ARGS_H_
#define FMT_ARGS_H_
#include <functional> // std::reference_wrapper
#include <memory> // std::unique_ptr
#include <vector>
#include "core.h"
FMT_BEGIN_NAMESPACE
namespace detail {
template <typename T> struct is_reference_wrapper : std::false_type {};
template <typename T>
struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
template <typename T> const T& unwrap(const T& v) { return v; }
template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {
return static_cast<const T&>(v);
}
class dynamic_arg_list {
// Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
// templates it doesn't complain about inability to deduce single translation
// unit for placing vtable. So storage_node_base is made a fake template.
template <typename = void> struct node {
virtual ~node() = default;
std::unique_ptr<node<>> next;
};
template <typename T> struct typed_node : node<> {
T value;
template <typename Arg>
FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}
template <typename Char>
FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)
: value(arg.data(), arg.size()) {}
};
std::unique_ptr<node<>> head_;
public:
template <typename T, typename Arg> const T& push(const Arg& arg) {
auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
auto& value = new_node->value;
new_node->next = std::move(head_);
head_ = std::move(new_node);
return value;
}
};
} // namespace detail
/**
\rst
A dynamic version of `fmt::format_arg_store`.
It's equipped with a storage to potentially temporary objects which lifetimes
could be shorter than the format arguments object.
It can be implicitly converted into `~fmt::basic_format_args` for passing
into type-erased formatting functions such as `~fmt::vformat`.
\endrst
*/
template <typename Context>
class dynamic_format_arg_store
#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
// Workaround a GCC template argument substitution bug.
: public basic_format_args<Context>
#endif
{
private:
using char_type = typename Context::char_type;
template <typename T> struct need_copy {
static constexpr detail::type mapped_type =
detail::mapped_type_constant<T, Context>::value;
enum {
value = !(detail::is_reference_wrapper<T>::value ||
std::is_same<T, basic_string_view<char_type>>::value ||
std::is_same<T, detail::std_string_view<char_type>>::value ||
(mapped_type != detail::type::cstring_type &&
mapped_type != detail::type::string_type &&
mapped_type != detail::type::custom_type))
};
};
template <typename T>
using stored_type = conditional_t<
std::is_convertible<T, std::basic_string<char_type>>::value &&
!detail::is_reference_wrapper<T>::value,
std::basic_string<char_type>, T>;
// Storage of basic_format_arg must be contiguous.
std::vector<basic_format_arg<Context>> data_;
std::vector<detail::named_arg_info<char_type>> named_info_;
// Storage of arguments not fitting into basic_format_arg must grow
// without relocation because items in data_ refer to it.
detail::dynamic_arg_list dynamic_args_;
friend class basic_format_args<Context>;
unsigned long long get_types() const {
return detail::is_unpacked_bit | data_.size() |
(named_info_.empty()
? 0ULL
: static_cast<unsigned long long>(detail::has_named_args_bit));
}
const basic_format_arg<Context>* data() const {
return named_info_.empty() ? data_.data() : data_.data() + 1;
}
template <typename T> void emplace_arg(const T& arg) {
data_.emplace_back(detail::make_arg<Context>(arg));
}
template <typename T>
void emplace_arg(const detail::named_arg<char_type, T>& arg) {
if (named_info_.empty()) {
constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};
data_.insert(data_.begin(), {zero_ptr, 0});
}
data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));
auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
data->pop_back();
};
std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
guard{&data_, pop_one};
named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
data_[0].value_.named_args = {named_info_.data(), named_info_.size()};
guard.release();
}
public:
constexpr dynamic_format_arg_store() = default;
/**
\rst
Adds an argument into the dynamic store for later passing to a formatting
function.
Note that custom types and string types (but not string views) are copied
into the store dynamically allocating memory if necessary.
**Example**::
fmt::dynamic_format_arg_store<fmt::format_context> store;
store.push_back(42);
store.push_back("abc");
store.push_back(1.5f);
std::string result = fmt::vformat("{} and {} and {}", store);
\endrst
*/
template <typename T> void push_back(const T& arg) {
if (detail::const_check(need_copy<T>::value))
emplace_arg(dynamic_args_.push<stored_type<T>>(arg));
else
emplace_arg(detail::unwrap(arg));
}
/**
\rst
Adds a reference to the argument into the dynamic store for later passing to
a formatting function.
**Example**::
fmt::dynamic_format_arg_store<fmt::format_context> store;
char band[] = "Rolling Stones";
store.push_back(std::cref(band));
band[9] = 'c'; // Changing str affects the output.
std::string result = fmt::vformat("{}", store);
// result == "Rolling Scones"
\endrst
*/
template <typename T> void push_back(std::reference_wrapper<T> arg) {
static_assert(
need_copy<T>::value,
"objects of built-in types and string views are always copied");
emplace_arg(arg.get());
}
/**
Adds named argument into the dynamic store for later passing to a formatting
function. ``std::reference_wrapper`` is supported to avoid copying of the
argument. The name is always copied into the store.
*/
template <typename T>
void push_back(const detail::named_arg<char_type, T>& arg) {
const char_type* arg_name =
dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
if (detail::const_check(need_copy<T>::value)) {
emplace_arg(
fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));
} else {
emplace_arg(fmt::arg(arg_name, arg.value));
}
}
/** Erase all elements from the store */
void clear() {
data_.clear();
named_info_.clear();
dynamic_args_ = detail::dynamic_arg_list();
}
/**
\rst
Reserves space to store at least *new_cap* arguments including
*new_cap_named* named arguments.
\endrst
*/
void reserve(size_t new_cap, size_t new_cap_named) {
FMT_ASSERT(new_cap >= new_cap_named,
"Set of arguments includes set of named arguments");
data_.reserve(new_cap);
named_info_.reserve(new_cap_named);
}
};
FMT_END_NAMESPACE
#endif // FMT_ARGS_H_