diff options
Diffstat (limited to 'third_party/abseil_cpp/absl/strings/internal/str_format/arg.h')
-rw-r--r-- | third_party/abseil_cpp/absl/strings/internal/str_format/arg.h | 48 |
1 files changed, 46 insertions, 2 deletions
diff --git a/third_party/abseil_cpp/absl/strings/internal/str_format/arg.h b/third_party/abseil_cpp/absl/strings/internal/str_format/arg.h index d441e87fff33..7040c866778e 100644 --- a/third_party/abseil_cpp/absl/strings/internal/str_format/arg.h +++ b/third_party/abseil_cpp/absl/strings/internal/str_format/arg.h @@ -1,3 +1,17 @@ +// Copyright 2020 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + #ifndef ABSL_STRINGS_INTERNAL_STR_FORMAT_ARG_H_ #define ABSL_STRINGS_INTERNAL_STR_FORMAT_ARG_H_ @@ -25,10 +39,12 @@ class Cord; class FormatCountCapture; class FormatSink; -namespace str_format_internal { - +template <absl::FormatConversionCharSet C> +struct FormatConvertResult; class FormatConversionSpec; +namespace str_format_internal { + template <typename T, typename = void> struct HasUserDefinedConvert : std::false_type {}; @@ -39,6 +55,22 @@ struct HasUserDefinedConvert<T, void_t<decltype(AbslFormatConvert( std::declval<FormatSink*>()))>> : std::true_type {}; +void AbslFormatConvert(); // Stops the lexical name lookup +template <typename T> +auto FormatConvertImpl(const T& v, FormatConversionSpecImpl conv, + FormatSinkImpl* sink) + -> decltype(AbslFormatConvert(v, + std::declval<const FormatConversionSpec&>(), + std::declval<FormatSink*>())) { + using FormatConversionSpecT = + absl::enable_if_t<sizeof(const T& (*)()) != 0, FormatConversionSpec>; + using FormatSinkT = + absl::enable_if_t<sizeof(const T& (*)()) != 0, FormatSink>; + auto fcs = conv.Wrap<FormatConversionSpecT>(); + auto fs = sink->Wrap<FormatSinkT>(); + return AbslFormatConvert(v, fcs, &fs); +} + template <typename T> class StreamedWrapper; @@ -46,6 +78,13 @@ class StreamedWrapper; // then convert it, appending to `sink` and return `true`. // Otherwise fail and return `false`. +// AbslFormatConvert(v, conv, sink) is intended to be found by ADL on 'v' +// as an extension mechanism. These FormatConvertImpl functions are the default +// implementations. +// The ADL search is augmented via the 'Sink*' parameter, which also +// serves as a disambiguator to reject possible unintended 'AbslFormatConvert' +// functions in the namespaces associated with 'v'. + // Raw pointers. struct VoidPtr { VoidPtr() = default; @@ -62,6 +101,11 @@ struct ArgConvertResult { }; template <FormatConversionCharSet C> +constexpr FormatConversionCharSet ExtractCharSet(FormatConvertResult<C>) { + return C; +} + +template <FormatConversionCharSet C> constexpr FormatConversionCharSet ExtractCharSet(ArgConvertResult<C>) { return C; } |