diff options
Diffstat (limited to 'absl/strings/internal/str_format/bind.h')
-rw-r--r-- | absl/strings/internal/str_format/bind.h | 47 |
1 files changed, 39 insertions, 8 deletions
diff --git a/absl/strings/internal/str_format/bind.h b/absl/strings/internal/str_format/bind.h index 267cc0ef..80f29654 100644 --- a/absl/strings/internal/str_format/bind.h +++ b/absl/strings/internal/str_format/bind.h @@ -25,6 +25,7 @@ #include "absl/strings/internal/str_format/checker.h" #include "absl/strings/internal/str_format/parser.h" #include "absl/types/span.h" +#include "absl/utility/utility.h" namespace absl { ABSL_NAMESPACE_BEGIN @@ -87,6 +88,36 @@ class FormatSpecTemplate : public MakeDependent<UntypedFormatSpec, Args...>::type { using Base = typename MakeDependent<UntypedFormatSpec, Args...>::type; + template <bool res> + struct ErrorMaker { + constexpr bool operator()(int) const { return res; } + }; + + template <int i, int j> + static constexpr bool CheckArity(ErrorMaker<true> SpecifierCount = {}, + ErrorMaker<i == j> ParametersPassed = {}) { + static_assert(SpecifierCount(i) == ParametersPassed(j), + "Number of arguments passed must match the number of " + "conversion specifiers."); + return true; + } + + template <FormatConversionCharSet specified, FormatConversionCharSet passed, + int arg> + static constexpr bool CheckMatch( + ErrorMaker<Contains(specified, passed)> MismatchedArgumentNumber = {}) { + static_assert(MismatchedArgumentNumber(arg), + "Passed argument must match specified format."); + return true; + } + + template <FormatConversionCharSet... C, size_t... I> + static bool CheckMatches(absl::index_sequence<I...>) { + bool res[] = {true, CheckMatch<Args, C, I + 1>()...}; + (void)res; + return true; + } + public: #ifdef ABSL_INTERNAL_ENABLE_FORMAT_CHECKER @@ -100,7 +131,7 @@ class FormatSpecTemplate // We use the 'unavailable' attribute to give a better compiler error than // just 'method is deleted'. // To avoid checking the format twice, we just check that the format is - // constexpr. If is it valid, then the overload below will kick in. + // constexpr. If it is valid, then the overload below will kick in. // We add the template here to make this overload have lower priority. template <typename = void> FormatSpecTemplate(const char* s) // NOLINT @@ -112,7 +143,8 @@ class FormatSpecTemplate template <typename T = void> FormatSpecTemplate(string_view s) // NOLINT __attribute__((enable_if(str_format_internal::EnsureConstexpr(s), - "constexpr trap"))) { + "constexpr trap"))) + : Base("to avoid noise in the compiler error") { static_assert(sizeof(T*) == 0, "Format specified does not match the arguments passed."); } @@ -133,13 +165,12 @@ class FormatSpecTemplate #endif // ABSL_INTERNAL_ENABLE_FORMAT_CHECKER - template < - FormatConversionCharSet... C, - typename = typename std::enable_if<sizeof...(C) == sizeof...(Args)>::type, - typename = typename std::enable_if<AllOf(Contains(Args, - C)...)>::type> + template <FormatConversionCharSet... C> FormatSpecTemplate(const ExtendedParsedFormat<C...>& pc) // NOLINT - : Base(&pc) {} + : Base(&pc) { + CheckArity<sizeof...(C), sizeof...(Args)>(); + CheckMatches<C...>(absl::make_index_sequence<sizeof...(C)>{}); + } }; class Streamable { |