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Improve handling of named arguments in compile-time checks

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This commit is contained in:
Victor Zverovich 2024-08-31 21:23:41 -07:00
parent db4becabed
commit f4dad85c3a
1 changed files with 40 additions and 44 deletions
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84
include/fmt/base.h
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@ -1341,8 +1341,7 @@ template <bool B1, bool B2, bool... Tail> constexpr auto count() -> size_t {
template <typename... Args> constexpr auto count_named_args() -> size_t {
return count<is_named_arg<Args>::value...>();
}
template <typename... Args>
constexpr auto count_statically_named_args() -> size_t {
template <typename... Args> constexpr auto count_static_named_args() -> size_t {
return count<is_statically_named_arg<Args>::value...>();
}
@ -2828,12 +2827,19 @@ FMT_CONSTEXPR void parse_format_string(basic_string_view<Char> format_str,
}
}
template <typename T, bool = is_named_arg<T>::value> struct strip_named_arg {
using type = T;
};
template <typename T> struct strip_named_arg<T, true> {
using type = remove_cvref_t<decltype(T::value)>;
};
// Checks char specs and returns true iff the presentation type is char-like.
FMT_CONSTEXPR inline auto check_char_specs(const format_specs& specs) -> bool {
auto type = specs.type();
if (type != presentation_type::none && type != presentation_type::chr &&
type != presentation_type::debug) {
return false;
}
if (specs.align() == align::numeric || specs.sign() != sign::none ||
specs.alt()) {
report_error("invalid format specifier for char");
}
return true;
}
template <typename T, typename ParseContext>
FMT_VISIBILITY("hidden") // Suppress an ld warning on macOS (#3769).
@ -2856,23 +2862,9 @@ FMT_CONSTEXPR auto parse_format_specs(ParseContext& ctx)
#endif
}
// Checks char specs and returns true iff the presentation type is char-like.
FMT_CONSTEXPR inline auto check_char_specs(const format_specs& specs) -> bool {
auto type = specs.type();
if (type != presentation_type::none && type != presentation_type::chr &&
type != presentation_type::debug) {
return false;
}
if (specs.align() == align::numeric || specs.sign() != sign::none ||
specs.alt()) {
report_error("invalid format specifier for char");
}
return true;
}
template <typename... T> struct arg_pack {};
template <typename Char, int NUM_ARGS, int NUM_NAMED_ARGS>
template <typename Char, int NUM_ARGS, int NUM_NAMED_ARGS, bool DYNAMIC_NAMES>
class format_string_checker {
private:
using parse_context_type = compile_parse_context<Char>;
@ -2908,13 +2900,14 @@ class format_string_checker {
FMT_CONSTEXPR auto on_arg_id() -> int { return context_.next_arg_id(); }
FMT_CONSTEXPR auto on_arg_id(int id) -> int {
return context_.check_arg_id(id), id;
context_.check_arg_id(id);
return id;
}
FMT_CONSTEXPR auto on_arg_id(basic_string_view<Char> id) -> int {
for (int i = 0; i < NUM_NAMED_ARGS; ++i) {
if (named_args_[i].name == id) return i;
if (named_args_[i].name == id) return named_args_[i].id;
}
on_error("named argument is not found");
if (!DYNAMIC_NAMES) on_error("argument not found");
return -1;
}
@ -2922,11 +2915,12 @@ class format_string_checker {
on_format_specs(id, begin, begin); // Call parse() on empty specs.
}
FMT_CONSTEXPR auto on_format_specs(int id, const Char* begin, const Char*)
FMT_CONSTEXPR auto on_format_specs(int id, const Char* begin, const Char* end)
-> const Char* {
context_.advance_to(begin);
// id >= 0 check is a workaround for gcc 10 bug (#2065).
return id >= 0 && id < NUM_ARGS ? parse_funcs_[id](context_) : begin;
if (id >= 0 && id < NUM_ARGS) return parse_funcs_[id](context_);
while (begin != end && *begin != '}') ++begin;
return begin;
}
FMT_NORETURN FMT_CONSTEXPR void on_error(const char* message) {
@ -3012,20 +3006,14 @@ template <typename Char, typename... Args> class basic_format_string {
private:
basic_string_view<Char> str_;
using checker = detail::format_string_checker<
Char, static_cast<int>(sizeof...(Args)),
detail::count_statically_named_args<Args...>()>;
static constexpr int num_static_named_args =
detail::count_static_named_args<Args...>();
FMT_CONSTEXPR FMT_ALWAYS_INLINE static void check(
basic_string_view<Char> fmt) {
using namespace detail;
static_assert(
count<(std::is_base_of<view, remove_reference_t<Args>>::value &&
std::is_reference<Args>::value)...>() == 0,
"passing views as lvalues is disallowed");
if (count_named_args<Args...>() == count_statically_named_args<Args...>())
parse_format_string(fmt, checker(fmt, arg_pack<Args...>()));
}
using checker = detail::format_string_checker<
Char, static_cast<int>(sizeof...(Args)), num_static_named_args,
num_static_named_args != detail::count_named_args<Args...>()>;
using arg_pack = detail::arg_pack<Args...>;
public:
// Reports a compile-time error if S is not a valid format string for Args.
@ -3033,7 +3021,13 @@ template <typename Char, typename... Args> class basic_format_string {
FMT_ENABLE_IF(
std::is_convertible<const S&, basic_string_view<Char>>::value)>
FMT_CONSTEVAL FMT_ALWAYS_INLINE basic_format_string(const S& s) : str_(s) {
if (FMT_USE_CONSTEVAL) check(s);
using namespace detail;
static_assert(
detail::count<(std::is_base_of<view, remove_reference_t<Args>>::value &&
std::is_reference<Args>::value)...>() == 0,
"passing views as lvalues is disallowed");
if (FMT_USE_CONSTEVAL)
parse_format_string<true, Char>(s, checker(s, arg_pack()));
#ifdef FMT_ENFORCE_COMPILE_STRING
static_assert(
FMT_USE_CONSTEVAL && sizeof(S) != 0,
@ -3045,7 +3039,9 @@ template <typename Char, typename... Args> class basic_format_string {
FMT_ENABLE_IF(std::is_base_of<detail::compile_string, S>::value&&
std::is_same<typename S::char_type, Char>::value)>
FMT_ALWAYS_INLINE basic_format_string(const S& s) : str_(s) {
FMT_CONSTEXPR int ignore = (check(basic_string_view<Char>(S())), 0);
FMT_CONSTEXPR auto fmt = basic_string_view<Char>(S());
FMT_CONSTEXPR int ignore =
(parse_format_string(fmt, checker(fmt, arg_pack())), 0);
detail::ignore_unused(ignore);
}
basic_format_string(runtime_format_string<Char> fmt) : str_(fmt.str) {}