chore(3p/abseil_cpp): unvendor abseil_cpp r/3786

we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>

1 files changed, 0 insertions, 813 deletions

diff --git a/third_party/abseil_cpp/absl/strings/str_format.h b/third_party/abseil_cpp/absl/strings/str_format.h
deleted file mode 100644
index 01465107e105..000000000000
--- a/third_party/abseil_cpp/absl/strings/str_format.h
+++ /dev/null
@@ -1,813 +0,0 @@
-//
-// Copyright 2018 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.
-//
-// -----------------------------------------------------------------------------
-// File: str_format.h
-// -----------------------------------------------------------------------------
-//
-// The `str_format` library is a typesafe replacement for the family of
-// `printf()` string formatting routines within the `<cstdio>` standard library
-// header. Like the `printf` family, `str_format` uses a "format string" to
-// perform argument substitutions based on types. See the `FormatSpec` section
-// below for format string documentation.
-//
-// Example:
-//
-//   std::string s = absl::StrFormat(
-//                      "%s %s You have $%d!", "Hello", name, dollars);
-//
-// The library consists of the following basic utilities:
-//
-//   * `absl::StrFormat()`, a type-safe replacement for `std::sprintf()`, to
-//     write a format string to a `string` value.
-//   * `absl::StrAppendFormat()` to append a format string to a `string`
-//   * `absl::StreamFormat()` to more efficiently write a format string to a
-//     stream, such as`std::cout`.
-//   * `absl::PrintF()`, `absl::FPrintF()` and `absl::SNPrintF()` as
-//     replacements for `std::printf()`, `std::fprintf()` and `std::snprintf()`.
-//
-//     Note: a version of `std::sprintf()` is not supported as it is
-//     generally unsafe due to buffer overflows.
-//
-// Additionally, you can provide a format string (and its associated arguments)
-// using one of the following abstractions:
-//
-//   * A `FormatSpec` class template fully encapsulates a format string and its
-//     type arguments and is usually provided to `str_format` functions as a
-//     variadic argument of type `FormatSpec<Arg...>`. The `FormatSpec<Args...>`
-//     template is evaluated at compile-time, providing type safety.
-//   * A `ParsedFormat` instance, which encapsulates a specific, pre-compiled
-//     format string for a specific set of type(s), and which can be passed
-//     between API boundaries. (The `FormatSpec` type should not be used
-//     directly except as an argument type for wrapper functions.)
-//
-// The `str_format` library provides the ability to output its format strings to
-// arbitrary sink types:
-//
-//   * A generic `Format()` function to write outputs to arbitrary sink types,
-//     which must implement a `FormatRawSink` interface.
-//
-//   * A `FormatUntyped()` function that is similar to `Format()` except it is
-//     loosely typed. `FormatUntyped()` is not a template and does not perform
-//     any compile-time checking of the format string; instead, it returns a
-//     boolean from a runtime check.
-//
-// In addition, the `str_format` library provides extension points for
-// augmenting formatting to new types.  See "StrFormat Extensions" below.
-
-#ifndef ABSL_STRINGS_STR_FORMAT_H_
-#define ABSL_STRINGS_STR_FORMAT_H_
-
-#include <cstdio>
-#include <string>
-
-#include "absl/strings/internal/str_format/arg.h"  // IWYU pragma: export
-#include "absl/strings/internal/str_format/bind.h"  // IWYU pragma: export
-#include "absl/strings/internal/str_format/checker.h"  // IWYU pragma: export
-#include "absl/strings/internal/str_format/extension.h"  // IWYU pragma: export
-#include "absl/strings/internal/str_format/parser.h"  // IWYU pragma: export
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-// UntypedFormatSpec
-//
-// A type-erased class that can be used directly within untyped API entry
-// points. An `UntypedFormatSpec` is specifically used as an argument to
-// `FormatUntyped()`.
-//
-// Example:
-//
-//   absl::UntypedFormatSpec format("%d");
-//   std::string out;
-//   CHECK(absl::FormatUntyped(&out, format, {absl::FormatArg(1)}));
-class UntypedFormatSpec {
- public:
-  UntypedFormatSpec() = delete;
-  UntypedFormatSpec(const UntypedFormatSpec&) = delete;
-  UntypedFormatSpec& operator=(const UntypedFormatSpec&) = delete;
-
-  explicit UntypedFormatSpec(string_view s) : spec_(s) {}
-
- protected:
-  explicit UntypedFormatSpec(const str_format_internal::ParsedFormatBase* pc)
-      : spec_(pc) {}
-
- private:
-  friend str_format_internal::UntypedFormatSpecImpl;
-  str_format_internal::UntypedFormatSpecImpl spec_;
-};
-
-// FormatStreamed()
-//
-// Takes a streamable argument and returns an object that can print it
-// with '%s'. Allows printing of types that have an `operator<<` but no
-// intrinsic type support within `StrFormat()` itself.
-//
-// Example:
-//
-//   absl::StrFormat("%s", absl::FormatStreamed(obj));
-template <typename T>
-str_format_internal::StreamedWrapper<T> FormatStreamed(const T& v) {
-  return str_format_internal::StreamedWrapper<T>(v);
-}
-
-// FormatCountCapture
-//
-// This class provides a way to safely wrap `StrFormat()` captures of `%n`
-// conversions, which denote the number of characters written by a formatting
-// operation to this point, into an integer value.
-//
-// This wrapper is designed to allow safe usage of `%n` within `StrFormat(); in
-// the `printf()` family of functions, `%n` is not safe to use, as the `int *`
-// buffer can be used to capture arbitrary data.
-//
-// Example:
-//
-//   int n = 0;
-//   std::string s = absl::StrFormat("%s%d%n", "hello", 123,
-//                       absl::FormatCountCapture(&n));
-//   EXPECT_EQ(8, n);
-class FormatCountCapture {
- public:
-  explicit FormatCountCapture(int* p) : p_(p) {}
-
- private:
-  // FormatCountCaptureHelper is used to define FormatConvertImpl() for this
-  // class.
-  friend struct str_format_internal::FormatCountCaptureHelper;
-  // Unused() is here because of the false positive from -Wunused-private-field
-  // p_ is used in the templated function of the friend FormatCountCaptureHelper
-  // class.
-  int* Unused() { return p_; }
-  int* p_;
-};
-
-// FormatSpec
-//
-// The `FormatSpec` type defines the makeup of a format string within the
-// `str_format` library. It is a variadic class template that is evaluated at
-// compile-time, according to the format string and arguments that are passed to
-// it.
-//
-// You should not need to manipulate this type directly. You should only name it
-// if you are writing wrapper functions which accept format arguments that will
-// be provided unmodified to functions in this library. Such a wrapper function
-// might be a class method that provides format arguments and/or internally uses
-// the result of formatting.
-//
-// For a `FormatSpec` to be valid at compile-time, it must be provided as
-// either:
-//
-// * A `constexpr` literal or `absl::string_view`, which is how it most often
-//   used.
-// * A `ParsedFormat` instantiation, which ensures the format string is
-//   valid before use. (See below.)
-//
-// Example:
-//
-//   // Provided as a string literal.
-//   absl::StrFormat("Welcome to %s, Number %d!", "The Village", 6);
-//
-//   // Provided as a constexpr absl::string_view.
-//   constexpr absl::string_view formatString = "Welcome to %s, Number %d!";
-//   absl::StrFormat(formatString, "The Village", 6);
-//
-//   // Provided as a pre-compiled ParsedFormat object.
-//   // Note that this example is useful only for illustration purposes.
-//   absl::ParsedFormat<'s', 'd'> formatString("Welcome to %s, Number %d!");
-//   absl::StrFormat(formatString, "TheVillage", 6);
-//
-// A format string generally follows the POSIX syntax as used within the POSIX
-// `printf` specification.
-//
-// (See http://pubs.opengroup.org/onlinepubs/9699919799/functions/fprintf.html.)
-//
-// In specific, the `FormatSpec` supports the following type specifiers:
-//   * `c` for characters
-//   * `s` for strings
-//   * `d` or `i` for integers
-//   * `o` for unsigned integer conversions into octal
-//   * `x` or `X` for unsigned integer conversions into hex
-//   * `u` for unsigned integers
-//   * `f` or `F` for floating point values into decimal notation
-//   * `e` or `E` for floating point values into exponential notation
-//   * `a` or `A` for floating point values into hex exponential notation
-//   * `g` or `G` for floating point values into decimal or exponential
-//     notation based on their precision
-//   * `p` for pointer address values
-//   * `n` for the special case of writing out the number of characters
-//     written to this point. The resulting value must be captured within an
-//     `absl::FormatCountCapture` type.
-//
-// Implementation-defined behavior:
-//   * A null pointer provided to "%s" or "%p" is output as "(nil)".
-//   * A non-null pointer provided to "%p" is output in hex as if by %#x or
-//     %#lx.
-//
-// NOTE: `o`, `x\X` and `u` will convert signed values to their unsigned
-// counterpart before formatting.
-//
-// Examples:
-//     "%c", 'a'                -> "a"
-//     "%c", 32                 -> " "
-//     "%s", "C"                -> "C"
-//     "%s", std::string("C++") -> "C++"
-//     "%d", -10                -> "-10"
-//     "%o", 10                 -> "12"
-//     "%x", 16                 -> "10"
-//     "%f", 123456789          -> "123456789.000000"
-//     "%e", .01                -> "1.00000e-2"
-//     "%a", -3.0               -> "-0x1.8p+1"
-//     "%g", .01                -> "1e-2"
-//     "%p", (void*)&value      -> "0x7ffdeb6ad2a4"
-//
-//     int n = 0;
-//     std::string s = absl::StrFormat(
-//         "%s%d%n", "hello", 123, absl::FormatCountCapture(&n));
-//     EXPECT_EQ(8, n);
-//
-// The `FormatSpec` intrinsically supports all of these fundamental C++ types:
-//
-// *   Characters: `char`, `signed char`, `unsigned char`
-// *   Integers: `int`, `short`, `unsigned short`, `unsigned`, `long`,
-//         `unsigned long`, `long long`, `unsigned long long`
-// *   Floating-point: `float`, `double`, `long double`
-//
-// However, in the `str_format` library, a format conversion specifies a broader
-// C++ conceptual category instead of an exact type. For example, `%s` binds to
-// any string-like argument, so `std::string`, `absl::string_view`, and
-// `const char*` are all accepted. Likewise, `%d` accepts any integer-like
-// argument, etc.
-
-template <typename... Args>
-using FormatSpec = str_format_internal::FormatSpecTemplate<
-    str_format_internal::ArgumentToConv<Args>()...>;
-
-// ParsedFormat
-//
-// A `ParsedFormat` is a class template representing a preparsed `FormatSpec`,
-// with template arguments specifying the conversion characters used within the
-// format string. Such characters must be valid format type specifiers, and
-// these type specifiers are checked at compile-time.
-//
-// Instances of `ParsedFormat` can be created, copied, and reused to speed up
-// formatting loops. A `ParsedFormat` may either be constructed statically, or
-// dynamically through its `New()` factory function, which only constructs a
-// runtime object if the format is valid at that time.
-//
-// Example:
-//
-//   // Verified at compile time.
-//   absl::ParsedFormat<'s', 'd'> formatString("Welcome to %s, Number %d!");
-//   absl::StrFormat(formatString, "TheVillage", 6);
-//
-//   // Verified at runtime.
-//   auto format_runtime = absl::ParsedFormat<'d'>::New(format_string);
-//   if (format_runtime) {
-//     value = absl::StrFormat(*format_runtime, i);
-//   } else {
-//     ... error case ...
-//   }
-
-#if defined(__cpp_nontype_template_parameter_auto)
-// If C++17 is available, an 'extended' format is also allowed that can specify
-// multiple conversion characters per format argument, using a combination of
-// `absl::FormatConversionCharSet` enum values (logically a set union)
-//  via the `|` operator. (Single character-based arguments are still accepted,
-// but cannot be combined). Some common conversions also have predefined enum
-// values, such as `absl::FormatConversionCharSet::kIntegral`.
-//
-// Example:
-//   // Extended format supports multiple conversion characters per argument,
-//   // specified via a combination of `FormatConversionCharSet` enums.
-//   using MyFormat = absl::ParsedFormat<absl::FormatConversionCharSet::d |
-//                                       absl::FormatConversionCharSet::x>;
-//   MyFormat GetFormat(bool use_hex) {
-//     if (use_hex) return MyFormat("foo %x bar");
-//     return MyFormat("foo %d bar");
-//   }
-//   // `format` can be used with any value that supports 'd' and 'x',
-//   // like `int`.
-//   auto format = GetFormat(use_hex);
-//   value = StringF(format, i);
-template <auto... Conv>
-using ParsedFormat = absl::str_format_internal::ExtendedParsedFormat<
-    absl::str_format_internal::ToFormatConversionCharSet(Conv)...>;
-#else
-template <char... Conv>
-using ParsedFormat = str_format_internal::ExtendedParsedFormat<
-    absl::str_format_internal::ToFormatConversionCharSet(Conv)...>;
-#endif  // defined(__cpp_nontype_template_parameter_auto)
-
-// StrFormat()
-//
-// Returns a `string` given a `printf()`-style format string and zero or more
-// additional arguments. Use it as you would `sprintf()`. `StrFormat()` is the
-// primary formatting function within the `str_format` library, and should be
-// used in most cases where you need type-safe conversion of types into
-// formatted strings.
-//
-// The format string generally consists of ordinary character data along with
-// one or more format conversion specifiers (denoted by the `%` character).
-// Ordinary character data is returned unchanged into the result string, while
-// each conversion specification performs a type substitution from
-// `StrFormat()`'s other arguments. See the comments for `FormatSpec` for full
-// information on the makeup of this format string.
-//
-// Example:
-//
-//   std::string s = absl::StrFormat(
-//       "Welcome to %s, Number %d!", "The Village", 6);
-//   EXPECT_EQ("Welcome to The Village, Number 6!", s);
-//
-// Returns an empty string in case of error.
-template <typename... Args>
-ABSL_MUST_USE_RESULT std::string StrFormat(const FormatSpec<Args...>& format,
-                                           const Args&... args) {
-  return str_format_internal::FormatPack(
-      str_format_internal::UntypedFormatSpecImpl::Extract(format),
-      {str_format_internal::FormatArgImpl(args)...});
-}
-
-// StrAppendFormat()
-//
-// Appends to a `dst` string given a format string, and zero or more additional
-// arguments, returning `*dst` as a convenience for chaining purposes. Appends
-// nothing in case of error (but possibly alters its capacity).
-//
-// Example:
-//
-//   std::string orig("For example PI is approximately ");
-//   std::cout << StrAppendFormat(&orig, "%12.6f", 3.14);
-template <typename... Args>
-std::string& StrAppendFormat(std::string* dst,
-                             const FormatSpec<Args...>& format,
-                             const Args&... args) {
-  return str_format_internal::AppendPack(
-      dst, str_format_internal::UntypedFormatSpecImpl::Extract(format),
-      {str_format_internal::FormatArgImpl(args)...});
-}
-
-// StreamFormat()
-//
-// Writes to an output stream given a format string and zero or more arguments,
-// generally in a manner that is more efficient than streaming the result of
-// `absl:: StrFormat()`. The returned object must be streamed before the full
-// expression ends.
-//
-// Example:
-//
-//   std::cout << StreamFormat("%12.6f", 3.14);
-template <typename... Args>
-ABSL_MUST_USE_RESULT str_format_internal::Streamable StreamFormat(
-    const FormatSpec<Args...>& format, const Args&... args) {
-  return str_format_internal::Streamable(
-      str_format_internal::UntypedFormatSpecImpl::Extract(format),
-      {str_format_internal::FormatArgImpl(args)...});
-}
-
-// PrintF()
-//
-// Writes to stdout given a format string and zero or more arguments. This
-// function is functionally equivalent to `std::printf()` (and type-safe);
-// prefer `absl::PrintF()` over `std::printf()`.
-//
-// Example:
-//
-//   std::string_view s = "Ulaanbaatar";
-//   absl::PrintF("The capital of Mongolia is %s", s);
-//
-//   Outputs: "The capital of Mongolia is Ulaanbaatar"
-//
-template <typename... Args>
-int PrintF(const FormatSpec<Args...>& format, const Args&... args) {
-  return str_format_internal::FprintF(
-      stdout, str_format_internal::UntypedFormatSpecImpl::Extract(format),
-      {str_format_internal::FormatArgImpl(args)...});
-}
-
-// FPrintF()
-//
-// Writes to a file given a format string and zero or more arguments. This
-// function is functionally equivalent to `std::fprintf()` (and type-safe);
-// prefer `absl::FPrintF()` over `std::fprintf()`.
-//
-// Example:
-//
-//   std::string_view s = "Ulaanbaatar";
-//   absl::FPrintF(stdout, "The capital of Mongolia is %s", s);
-//
-//   Outputs: "The capital of Mongolia is Ulaanbaatar"
-//
-template <typename... Args>
-int FPrintF(std::FILE* output, const FormatSpec<Args...>& format,
-            const Args&... args) {
-  return str_format_internal::FprintF(
-      output, str_format_internal::UntypedFormatSpecImpl::Extract(format),
-      {str_format_internal::FormatArgImpl(args)...});
-}
-
-// SNPrintF()
-//
-// Writes to a sized buffer given a format string and zero or more arguments.
-// This function is functionally equivalent to `std::snprintf()` (and
-// type-safe); prefer `absl::SNPrintF()` over `std::snprintf()`.
-//
-// In particular, a successful call to `absl::SNPrintF()` writes at most `size`
-// bytes of the formatted output to `output`, including a NUL-terminator, and
-// returns the number of bytes that would have been written if truncation did
-// not occur. In the event of an error, a negative value is returned and `errno`
-// is set.
-//
-// Example:
-//
-//   std::string_view s = "Ulaanbaatar";
-//   char output[128];
-//   absl::SNPrintF(output, sizeof(output),
-//                  "The capital of Mongolia is %s", s);
-//
-//   Post-condition: output == "The capital of Mongolia is Ulaanbaatar"
-//
-template <typename... Args>
-int SNPrintF(char* output, std::size_t size, const FormatSpec<Args...>& format,
-             const Args&... args) {
-  return str_format_internal::SnprintF(
-      output, size, str_format_internal::UntypedFormatSpecImpl::Extract(format),
-      {str_format_internal::FormatArgImpl(args)...});
-}
-
-// -----------------------------------------------------------------------------
-// Custom Output Formatting Functions
-// -----------------------------------------------------------------------------
-
-// FormatRawSink
-//
-// FormatRawSink is a type erased wrapper around arbitrary sink objects
-// specifically used as an argument to `Format()`.
-//
-// All the object has to do define an overload of `AbslFormatFlush()` for the
-// sink, usually by adding a ADL-based free function in the same namespace as
-// the sink:
-//
-//   void AbslFormatFlush(MySink* dest, absl::string_view part);
-//
-// where `dest` is the pointer passed to `absl::Format()`. The function should
-// append `part` to `dest`.
-//
-// FormatRawSink does not own the passed sink object. The passed object must
-// outlive the FormatRawSink.
-class FormatRawSink {
- public:
-  // Implicitly convert from any type that provides the hook function as
-  // described above.
-  template <typename T,
-            typename = typename std::enable_if<std::is_constructible<
-                str_format_internal::FormatRawSinkImpl, T*>::value>::type>
-  FormatRawSink(T* raw)  // NOLINT
-      : sink_(raw) {}
-
- private:
-  friend str_format_internal::FormatRawSinkImpl;
-  str_format_internal::FormatRawSinkImpl sink_;
-};
-
-// Format()
-//
-// Writes a formatted string to an arbitrary sink object (implementing the
-// `absl::FormatRawSink` interface), using a format string and zero or more
-// additional arguments.
-//
-// By default, `std::string`, `std::ostream`, and `absl::Cord` are supported as
-// destination objects. If a `std::string` is used the formatted string is
-// appended to it.
-//
-// `absl::Format()` is a generic version of `absl::StrAppendFormat()`, for
-// custom sinks. The format string, like format strings for `StrFormat()`, is
-// checked at compile-time.
-//
-// On failure, this function returns `false` and the state of the sink is
-// unspecified.
-template <typename... Args>
-bool Format(FormatRawSink raw_sink, const FormatSpec<Args...>& format,
-            const Args&... args) {
-  return str_format_internal::FormatUntyped(
-      str_format_internal::FormatRawSinkImpl::Extract(raw_sink),
-      str_format_internal::UntypedFormatSpecImpl::Extract(format),
-      {str_format_internal::FormatArgImpl(args)...});
-}
-
-// FormatArg
-//
-// A type-erased handle to a format argument specifically used as an argument to
-// `FormatUntyped()`. You may construct `FormatArg` by passing
-// reference-to-const of any printable type. `FormatArg` is both copyable and
-// assignable. The source data must outlive the `FormatArg` instance. See
-// example below.
-//
-using FormatArg = str_format_internal::FormatArgImpl;
-
-// FormatUntyped()
-//
-// Writes a formatted string to an arbitrary sink object (implementing the
-// `absl::FormatRawSink` interface), using an `UntypedFormatSpec` and zero or
-// more additional arguments.
-//
-// This function acts as the most generic formatting function in the
-// `str_format` library. The caller provides a raw sink, an unchecked format
-// string, and (usually) a runtime specified list of arguments; no compile-time
-// checking of formatting is performed within this function. As a result, a
-// caller should check the return value to verify that no error occurred.
-// On failure, this function returns `false` and the state of the sink is
-// unspecified.
-//
-// The arguments are provided in an `absl::Span<const absl::FormatArg>`.
-// Each `absl::FormatArg` object binds to a single argument and keeps a
-// reference to it. The values used to create the `FormatArg` objects must
-// outlive this function call. (See `str_format_arg.h` for information on
-// the `FormatArg` class.)_
-//
-// Example:
-//
-//   std::optional<std::string> FormatDynamic(
-//       const std::string& in_format,
-//       const vector<std::string>& in_args) {
-//     std::string out;
-//     std::vector<absl::FormatArg> args;
-//     for (const auto& v : in_args) {
-//       // It is important that 'v' is a reference to the objects in in_args.
-//       // The values we pass to FormatArg must outlive the call to
-//       // FormatUntyped.
-//       args.emplace_back(v);
-//     }
-//     absl::UntypedFormatSpec format(in_format);
-//     if (!absl::FormatUntyped(&out, format, args)) {
-//       return std::nullopt;
-//     }
-//     return std::move(out);
-//   }
-//
-ABSL_MUST_USE_RESULT inline bool FormatUntyped(
-    FormatRawSink raw_sink, const UntypedFormatSpec& format,
-    absl::Span<const FormatArg> args) {
-  return str_format_internal::FormatUntyped(
-      str_format_internal::FormatRawSinkImpl::Extract(raw_sink),
-      str_format_internal::UntypedFormatSpecImpl::Extract(format), args);
-}
-
-//------------------------------------------------------------------------------
-// StrFormat Extensions
-//------------------------------------------------------------------------------
-//
-// AbslFormatConvert()
-//
-// The StrFormat library provides a customization API for formatting
-// user-defined types using absl::StrFormat(). The API relies on detecting an
-// overload in the user-defined type's namespace of a free (non-member)
-// `AbslFormatConvert()` function, usually as a friend definition with the
-// following signature:
-//
-// absl::FormatConvertResult<...> AbslFormatConvert(
-//     const X& value,
-//     const absl::FormatConversionSpec& spec,
-//     absl::FormatSink *sink);
-//
-// An `AbslFormatConvert()` overload for a type should only be declared in the
-// same file and namespace as said type.
-//
-// The abstractions within this definition include:
-//
-// * An `absl::FormatConversionSpec` to specify the fields to pull from a
-//   user-defined type's format string
-// * An `absl::FormatSink` to hold the converted string data during the
-//   conversion process.
-// * An `absl::FormatConvertResult` to hold the status of the returned
-//   formatting operation
-//
-// The return type encodes all the conversion characters that your
-// AbslFormatConvert() routine accepts.  The return value should be {true}.
-// A return value of {false} will result in `StrFormat()` returning
-// an empty string.  This result will be propagated to the result of
-// `FormatUntyped`.
-//
-// Example:
-//
-// struct Point {
-//   // To add formatting support to `Point`, we simply need to add a free
-//   // (non-member) function `AbslFormatConvert()`.  This method interprets
-//   // `spec` to print in the request format. The allowed conversion characters
-//   // can be restricted via the type of the result, in this example
-//   // string and integral formatting are allowed (but not, for instance
-//   // floating point characters like "%f").  You can add such a free function
-//   // using a friend declaration within the body of the class:
-//   friend absl::FormatConvertResult<absl::FormatConversionCharSet::kString |
-//                                    absl::FormatConversionCharSet::kIntegral>
-//   AbslFormatConvert(const Point& p, const absl::FormatConversionSpec& spec,
-//                     absl::FormatSink* s) {
-//     if (spec.conversion_char() == absl::FormatConversionChar::s) {
-//       s->Append(absl::StrCat("x=", p.x, " y=", p.y));
-//     } else {
-//       s->Append(absl::StrCat(p.x, ",", p.y));
-//     }
-//     return {true};
-//   }
-//
-//   int x;
-//   int y;
-// };
-
-// clang-format off
-
-// FormatConversionChar
-//
-// Specifies the formatting character provided in the format string
-// passed to `StrFormat()`.
-enum class FormatConversionChar : uint8_t {
-  c, s,                    // text
-  d, i, o, u, x, X,        // int
-  f, F, e, E, g, G, a, A,  // float
-  n, p                     // misc
-};
-// clang-format on
-
-// FormatConversionSpec
-//
-// Specifies modifications to the conversion of the format string, through use
-// of one or more format flags in the source format string.
-class FormatConversionSpec {
- public:
-  // FormatConversionSpec::is_basic()
-  //
-  // Indicates that width and precision are not specified, and no additional
-  // flags are set for this conversion character in the format string.
-  bool is_basic() const { return impl_.is_basic(); }
-
-  // FormatConversionSpec::has_left_flag()
-  //
-  // Indicates whether the result should be left justified for this conversion
-  // character in the format string. This flag is set through use of a '-'
-  // character in the format string. E.g. "%-s"
-  bool has_left_flag() const { return impl_.has_left_flag(); }
-
-  // FormatConversionSpec::has_show_pos_flag()
-  //
-  // Indicates whether a sign column is prepended to the result for this
-  // conversion character in the format string, even if the result is positive.
-  // This flag is set through use of a '+' character in the format string.
-  // E.g. "%+d"
-  bool has_show_pos_flag() const { return impl_.has_show_pos_flag(); }
-
-  // FormatConversionSpec::has_sign_col_flag()
-  //
-  // Indicates whether a mandatory sign column is added to the result for this
-  // conversion character. This flag is set through use of a space character
-  // (' ') in the format string. E.g. "% i"
-  bool has_sign_col_flag() const { return impl_.has_sign_col_flag(); }
-
-  // FormatConversionSpec::has_alt_flag()
-  //
-  // Indicates whether an "alternate" format is applied to the result for this
-  // conversion character. Alternative forms depend on the type of conversion
-  // character, and unallowed alternatives are undefined. This flag is set
-  // through use of a '#' character in the format string. E.g. "%#h"
-  bool has_alt_flag() const { return impl_.has_alt_flag(); }
-
-  // FormatConversionSpec::has_zero_flag()
-  //
-  // Indicates whether zeroes should be prepended to the result for this
-  // conversion character instead of spaces. This flag is set through use of the
-  // '0' character in the format string. E.g. "%0f"
-  bool has_zero_flag() const { return impl_.has_zero_flag(); }
-
-  // FormatConversionSpec::conversion_char()
-  //
-  // Returns the underlying conversion character.
-  FormatConversionChar conversion_char() const {
-    return impl_.conversion_char();
-  }
-
-  // FormatConversionSpec::width()
-  //
-  // Returns the specified width (indicated through use of a non-zero integer
-  // value or '*' character) of the conversion character. If width is
-  // unspecified, it returns a negative value.
-  int width() const { return impl_.width(); }
-
-  // FormatConversionSpec::precision()
-  //
-  // Returns the specified precision (through use of the '.' character followed
-  // by a non-zero integer value or '*' character) of the conversion character.
-  // If precision is unspecified, it returns a negative value.
-  int precision() const { return impl_.precision(); }
-
- private:
-  explicit FormatConversionSpec(
-      str_format_internal::FormatConversionSpecImpl impl)
-      : impl_(impl) {}
-
-  friend str_format_internal::FormatConversionSpecImpl;
-
-  absl::str_format_internal::FormatConversionSpecImpl impl_;
-};
-
-// Type safe OR operator for FormatConversionCharSet to allow accepting multiple
-// conversion chars in custom format converters.
-constexpr FormatConversionCharSet operator|(FormatConversionCharSet a,
-                                            FormatConversionCharSet b) {
-  return static_cast<FormatConversionCharSet>(static_cast<uint64_t>(a) |
-                                              static_cast<uint64_t>(b));
-}
-
-// FormatConversionCharSet
-//
-// Specifies the _accepted_ conversion types as a template parameter to
-// FormatConvertResult for custom implementations of `AbslFormatConvert`.
-// Note the helper predefined alias definitions (kIntegral, etc.) below.
-enum class FormatConversionCharSet : uint64_t {
-  // text
-  c = str_format_internal::FormatConversionCharToConvInt('c'),
-  s = str_format_internal::FormatConversionCharToConvInt('s'),
-  // integer
-  d = str_format_internal::FormatConversionCharToConvInt('d'),
-  i = str_format_internal::FormatConversionCharToConvInt('i'),
-  o = str_format_internal::FormatConversionCharToConvInt('o'),
-  u = str_format_internal::FormatConversionCharToConvInt('u'),
-  x = str_format_internal::FormatConversionCharToConvInt('x'),
-  X = str_format_internal::FormatConversionCharToConvInt('X'),
-  // Float
-  f = str_format_internal::FormatConversionCharToConvInt('f'),
-  F = str_format_internal::FormatConversionCharToConvInt('F'),
-  e = str_format_internal::FormatConversionCharToConvInt('e'),
-  E = str_format_internal::FormatConversionCharToConvInt('E'),
-  g = str_format_internal::FormatConversionCharToConvInt('g'),
-  G = str_format_internal::FormatConversionCharToConvInt('G'),
-  a = str_format_internal::FormatConversionCharToConvInt('a'),
-  A = str_format_internal::FormatConversionCharToConvInt('A'),
-  // misc
-  n = str_format_internal::FormatConversionCharToConvInt('n'),
-  p = str_format_internal::FormatConversionCharToConvInt('p'),
-
-  // Used for width/precision '*' specification.
-  kStar = static_cast<uint64_t>(
-      absl::str_format_internal::FormatConversionCharSetInternal::kStar),
-  // Some predefined values:
-  kIntegral = d | i | u | o | x | X,
-  kFloating = a | e | f | g | A | E | F | G,
-  kNumeric = kIntegral | kFloating,
-  kString = s,
-  kPointer = p,
-};
-
-// FormatSink
-//
-// An abstraction to which conversions write their string data.
-//
-class FormatSink {
- public:
-  // Appends `count` copies of `ch`.
-  void Append(size_t count, char ch) { sink_->Append(count, ch); }
-
-  void Append(string_view v) { sink_->Append(v); }
-
-  // Appends the first `precision` bytes of `v`. If this is less than
-  // `width`, spaces will be appended first (if `left` is false), or
-  // after (if `left` is true) to ensure the total amount appended is
-  // at least `width`.
-  bool PutPaddedString(string_view v, int width, int precision, bool left) {
-    return sink_->PutPaddedString(v, width, precision, left);
-  }
-
- private:
-  friend str_format_internal::FormatSinkImpl;
-  explicit FormatSink(str_format_internal::FormatSinkImpl* s) : sink_(s) {}
-  str_format_internal::FormatSinkImpl* sink_;
-};
-
-// FormatConvertResult
-//
-// Indicates whether a call to AbslFormatConvert() was successful.
-// This return type informs the StrFormat extension framework (through
-// ADL but using the return type) of what conversion characters are supported.
-// It is strongly discouraged to return {false}, as this will result in an
-// empty string in StrFormat.
-template <FormatConversionCharSet C>
-struct FormatConvertResult {
-  bool value;
-};
-
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_STRINGS_STR_FORMAT_H_