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// 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
//
//
// 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_
#include <string.h>
#include <wchar.h>
#include <algorithm>
#include <cstdio>
#include <iomanip>
#include <limits>
#include <memory>
#include <sstream>
#include <string>
#include <type_traits>
#include <utility>
#include "absl/base/port.h"
#include "absl/meta/type_traits.h"
#include "absl/numeric/int128.h"
#include "absl/strings/has_absl_stringify.h"
#include "absl/strings/internal/str_format/extension.h"
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
class Cord;
class FormatCountCapture;
class FormatSink;
template <absl::FormatConversionCharSet C>
struct FormatConvertResult;
class FormatConversionSpec;
namespace str_format_internal {
template <FormatConversionCharSet C>
struct ArgConvertResult {
bool value;
};
using IntegralConvertResult = ArgConvertResult<FormatConversionCharSetUnion(
FormatConversionCharSetInternal::c,
FormatConversionCharSetInternal::kNumeric,
FormatConversionCharSetInternal::kStar,
FormatConversionCharSetInternal::v)>;
using FloatingConvertResult = ArgConvertResult<FormatConversionCharSetUnion(
FormatConversionCharSetInternal::kFloating,
FormatConversionCharSetInternal::v)>;
using CharConvertResult = ArgConvertResult<FormatConversionCharSetUnion(
FormatConversionCharSetInternal::c,
FormatConversionCharSetInternal::kNumeric,
FormatConversionCharSetInternal::kStar)>;
template <typename T, typename = void>
struct HasUserDefinedConvert : std::false_type {};
template <typename T>
struct HasUserDefinedConvert<T, void_t<decltype(AbslFormatConvert(
std::declval<const T&>(),
std::declval<const FormatConversionSpec&>(),
std::declval<FormatSink*>()))>>
: std::true_type {};
// These declarations prevent ADL lookup from continuing in absl namespaces,
// we are deliberately using these as ADL hooks and want them to consider
// non-absl namespaces only.
void AbslFormatConvert();
void AbslStringify();
template <typename T>
bool ConvertIntArg(T v, FormatConversionSpecImpl conv, FormatSinkImpl* sink);
// Forward declarations of internal `ConvertIntArg` function template
// instantiations are here to avoid including the template body in the headers
// and instantiating it in large numbers of translation units. Explicit
// instantiations can be found in "absl/strings/internal/str_format/arg.cc"
extern template bool ConvertIntArg<char>(char v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<signed char>(signed char v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<unsigned char>(unsigned char v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<short>(short v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<unsigned short>( // NOLINT
unsigned short v, FormatConversionSpecImpl conv, // NOLINT
FormatSinkImpl* sink);
extern template bool ConvertIntArg<int>(int v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<unsigned int>(unsigned int v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<long>( // NOLINT
long v, FormatConversionSpecImpl conv, FormatSinkImpl* sink); // NOLINT
extern template bool ConvertIntArg<unsigned long>(unsigned long v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<long long>(long long v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
extern template bool ConvertIntArg<unsigned long long>( // NOLINT
unsigned long long v, FormatConversionSpecImpl conv, // NOLINT
FormatSinkImpl* sink);
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>
auto FormatConvertImpl(const T& v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink)
-> std::enable_if_t<std::is_enum<T>::value &&
std::is_void<decltype(AbslStringify(
std::declval<FormatSink&>(), v))>::value,
IntegralConvertResult> {
if (conv.conversion_char() == FormatConversionCharInternal::v) {
using FormatSinkT =
absl::enable_if_t<sizeof(const T& (*)()) != 0, FormatSink>;
auto fs = sink->Wrap<FormatSinkT>();
AbslStringify(fs, v);
return {true};
} else {
return {ConvertIntArg(
static_cast<typename std::underlying_type<T>::type>(v), conv, sink)};
}
}
template <typename T>
auto FormatConvertImpl(const T& v, FormatConversionSpecImpl,
FormatSinkImpl* sink)
-> std::enable_if_t<!std::is_enum<T>::value &&
std::is_void<decltype(AbslStringify(
std::declval<FormatSink&>(), v))>::value,
ArgConvertResult<FormatConversionCharSetInternal::v>> {
using FormatSinkT =
absl::enable_if_t<sizeof(const T& (*)()) != 0, FormatSink>;
auto fs = sink->Wrap<FormatSinkT>();
AbslStringify(fs, v);
return {true};
}
template <typename T>
class StreamedWrapper;
// If 'v' can be converted (in the printf sense) according to 'conv',
// 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;
template <typename T,
decltype(reinterpret_cast<uintptr_t>(std::declval<T*>())) = 0>
VoidPtr(T* ptr) // NOLINT
: value(ptr ? reinterpret_cast<uintptr_t>(ptr) : 0) {}
uintptr_t value;
};
template <FormatConversionCharSet C>
constexpr FormatConversionCharSet ExtractCharSet(FormatConvertResult<C>) {
return C;
}
template <FormatConversionCharSet C>
constexpr FormatConversionCharSet ExtractCharSet(ArgConvertResult<C>) {
return C;
}
using StringConvertResult = ArgConvertResult<FormatConversionCharSetUnion(
FormatConversionCharSetInternal::s, FormatConversionCharSetInternal::v)>;
ArgConvertResult<FormatConversionCharSetInternal::p> FormatConvertImpl(
VoidPtr v, FormatConversionSpecImpl conv, FormatSinkImpl* sink);
// Strings.
StringConvertResult FormatConvertImpl(const std::string& v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
StringConvertResult FormatConvertImpl(string_view v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
#if defined(ABSL_HAVE_STD_STRING_VIEW) && !defined(ABSL_USES_STD_STRING_VIEW)
inline StringConvertResult FormatConvertImpl(std::string_view v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink) {
return FormatConvertImpl(absl::string_view(v.data(), v.size()), conv, sink);
}
#endif // ABSL_HAVE_STD_STRING_VIEW && !ABSL_USES_STD_STRING_VIEW
ArgConvertResult<FormatConversionCharSetUnion(
FormatConversionCharSetInternal::s, FormatConversionCharSetInternal::p)>
FormatConvertImpl(const char* v, const FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
template <class AbslCord, typename std::enable_if<std::is_same<
AbslCord, absl::Cord>::value>::type* = nullptr>
StringConvertResult FormatConvertImpl(const AbslCord& value,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink) {
bool is_left = conv.has_left_flag();
size_t space_remaining = 0;
int width = conv.width();
if (width >= 0) space_remaining = static_cast<size_t>(width);
size_t to_write = value.size();
int precision = conv.precision();
if (precision >= 0)
to_write = (std::min)(to_write, static_cast<size_t>(precision));
space_remaining = Excess(to_write, space_remaining);
if (space_remaining > 0 && !is_left) sink->Append(space_remaining, ' ');
for (string_view piece : value.Chunks()) {
if (piece.size() > to_write) {
piece.remove_suffix(piece.size() - to_write);
to_write = 0;
} else {
to_write -= piece.size();
}
sink->Append(piece);
if (to_write == 0) {
break;
}
}
if (space_remaining > 0 && is_left) sink->Append(space_remaining, ' ');
return {true};
}
bool ConvertBoolArg(bool v, FormatSinkImpl* sink);
// Floats.
FloatingConvertResult FormatConvertImpl(float v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
FloatingConvertResult FormatConvertImpl(double v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
FloatingConvertResult FormatConvertImpl(long double v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
// Chars.
CharConvertResult FormatConvertImpl(char v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
// Ints.
IntegralConvertResult FormatConvertImpl(signed char v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned char v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(short v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned short v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(int v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(long v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned long v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(long long v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned long long v, // NOLINT
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(int128 v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(uint128 v,
FormatConversionSpecImpl conv,
FormatSinkImpl* sink);
// This function needs to be a template due to ambiguity regarding type
// conversions.
template <typename T, enable_if_t<std::is_same<T, bool>::value, int> = 0>
IntegralConvertResult FormatConvertImpl(T v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink) {
if (conv.conversion_char() == FormatConversionCharInternal::v) {
return {ConvertBoolArg(v, sink)};
}
return FormatConvertImpl(static_cast<int>(v), conv, sink);
}
// We provide this function to help the checker, but it is never defined.
// FormatArgImpl will use the underlying Convert functions instead.
template <typename T>
typename std::enable_if<std::is_enum<T>::value &&
!HasUserDefinedConvert<T>::value &&
!HasAbslStringify<T>::value,
IntegralConvertResult>::type
FormatConvertImpl(T v, FormatConversionSpecImpl conv, FormatSinkImpl* sink);
template <typename T>
StringConvertResult FormatConvertImpl(const StreamedWrapper<T>& v,
FormatConversionSpecImpl conv,
FormatSinkImpl* out) {
std::ostringstream oss;
oss << v.v_;
if (!oss) return {false};
return str_format_internal::FormatConvertImpl(oss.str(), conv, out);
}
// Use templates and dependent types to delay evaluation of the function
// until after FormatCountCapture is fully defined.
struct FormatCountCaptureHelper {
template <class T = int>
static ArgConvertResult<FormatConversionCharSetInternal::n> ConvertHelper(
const FormatCountCapture& v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink) {
const absl::enable_if_t<sizeof(T) != 0, FormatCountCapture>& v2 = v;
if (conv.conversion_char() !=
str_format_internal::FormatConversionCharInternal::n) {
return {false};
}
*v2.p_ = static_cast<int>(sink->size());
return {true};
}
};
template <class T = int>
ArgConvertResult<FormatConversionCharSetInternal::n> FormatConvertImpl(
const FormatCountCapture& v, FormatConversionSpecImpl conv,
FormatSinkImpl* sink) {
return FormatCountCaptureHelper::ConvertHelper(v, conv, sink);
}
// Helper friend struct to hide implementation details from the public API of
// FormatArgImpl.
struct FormatArgImplFriend {
template <typename Arg>
static bool ToInt(Arg arg, int* out) {
// A value initialized FormatConversionSpecImpl has a `none` conv, which
// tells the dispatcher to run the `int` conversion.
return arg.dispatcher_(arg.data_, {}, out);
}
template <typename Arg>
static bool Convert(Arg arg, FormatConversionSpecImpl conv,
FormatSinkImpl* out) {
return arg.dispatcher_(arg.data_, conv, out);
}
template <typename Arg>
static typename Arg::Dispatcher GetVTablePtrForTest(Arg arg) {
return arg.dispatcher_;
}
};
template <typename Arg>
constexpr FormatConversionCharSet ArgumentToConv() {
using ConvResult = decltype(str_format_internal::FormatConvertImpl(
std::declval<const Arg&>(),
std::declval<const FormatConversionSpecImpl&>(),
std::declval<FormatSinkImpl*>()));
return absl::str_format_internal::ExtractCharSet(ConvResult{});
}
// A type-erased handle to a format argument.
class FormatArgImpl {
private:
enum { kInlinedSpace = 8 };
using VoidPtr = str_format_internal::VoidPtr;
union Data {
const void* ptr;
const volatile void* volatile_ptr;
char buf[kInlinedSpace];
};
using Dispatcher = bool (*)(Data, FormatConversionSpecImpl, void* out);
template <typename T>
struct store_by_value
: std::integral_constant<bool, (sizeof(T) <= kInlinedSpace) &&
(std::is_integral<T>::value ||
std::is_floating_point<T>::value ||
std::is_pointer<T>::value ||
std::is_same<VoidPtr, T>::value)> {};
enum StoragePolicy { ByPointer, ByVolatilePointer, ByValue };
template <typename T>
struct storage_policy
: std::integral_constant<StoragePolicy,
(std::is_volatile<T>::value
? ByVolatilePointer
: (store_by_value<T>::value ? ByValue
: ByPointer))> {
};
// To reduce the number of vtables we will decay values before hand.
// Anything with a user-defined Convert will get its own vtable.
// For everything else:
// - Decay char* and char arrays into `const char*`
// - Decay any other pointer to `const void*`
// - Decay all enums to the integral promotion of their underlying type.
// - Decay function pointers to void*.
template <typename T, typename = void>
struct DecayType {
static constexpr bool kHasUserDefined =
str_format_internal::HasUserDefinedConvert<T>::value ||
HasAbslStringify<T>::value;
using type = typename std::conditional<
!kHasUserDefined && std::is_convertible<T, const char*>::value,
const char*,
typename std::conditional<!kHasUserDefined &&
std::is_convertible<T, VoidPtr>::value,
VoidPtr, const T&>::type>::type;
};
template <typename T>
struct DecayType<
T, typename std::enable_if<
!str_format_internal::HasUserDefinedConvert<T>::value &&
!HasAbslStringify<T>::value && std::is_enum<T>::value>::type> {
using type = decltype(+typename std::underlying_type<T>::type());
};
public:
template <typename T>
explicit FormatArgImpl(const T& value) {
using D = typename DecayType<T>::type;
static_assert(
std::is_same<D, const T&>::value || storage_policy<D>::value == ByValue,
"Decayed types must be stored by value");
Init(static_cast<D>(value));
}
private:
friend struct str_format_internal::FormatArgImplFriend;
template <typename T, StoragePolicy = storage_policy<T>::value>
struct Manager;
template <typename T>
struct Manager<T, ByPointer> {
static Data SetValue(const T& value) {
Data data;
data.ptr = std::addressof(value);
return data;
}
static const T& Value(Data arg) { return *static_cast<const T*>(arg.ptr); }
};
template <typename T>
struct Manager<T, ByVolatilePointer> {
static Data SetValue(const T& value) {
Data data;
data.volatile_ptr = &value;
return data;
}
static const T& Value(Data arg) {
return *static_cast<const T*>(arg.volatile_ptr);
}
};
template <typename T>
struct Manager<T, ByValue> {
static Data SetValue(const T& value) {
Data data;
memcpy(data.buf, &value, sizeof(value));
return data;
}
static T Value(Data arg) {
T value;
memcpy(&value, arg.buf, sizeof(T));
return value;
}
};
template <typename T>
void Init(const T& value) {
data_ = Manager<T>::SetValue(value);
dispatcher_ = &Dispatch<T>;
}
template <typename T>
static int ToIntVal(const T& val) {
using CommonType = typename std::conditional<std::is_signed<T>::value,
int64_t, uint64_t>::type;
if (static_cast<CommonType>(val) >
static_cast<CommonType>((std::numeric_limits<int>::max)())) {
return (std::numeric_limits<int>::max)();
} else if (std::is_signed<T>::value &&
static_cast<CommonType>(val) <
static_cast<CommonType>((std::numeric_limits<int>::min)())) {
return (std::numeric_limits<int>::min)();
}
return static_cast<int>(val);
}
template <typename T>
static bool ToInt(Data arg, int* out, std::true_type /* is_integral */,
std::false_type) {
*out = ToIntVal(Manager<T>::Value(arg));
return true;
}
template <typename T>
static bool ToInt(Data arg, int* out, std::false_type,
std::true_type /* is_enum */) {
*out = ToIntVal(static_cast<typename std::underlying_type<T>::type>(
Manager<T>::Value(arg)));
return true;
}
template <typename T>
static bool ToInt(Data, int*, std::false_type, std::false_type) {
return false;
}
template <typename T>
static bool Dispatch(Data arg, FormatConversionSpecImpl spec, void* out) {
// A `none` conv indicates that we want the `int` conversion.
if (ABSL_PREDICT_FALSE(spec.conversion_char() ==
FormatConversionCharInternal::kNone)) {
return ToInt<T>(arg, static_cast<int*>(out), std::is_integral<T>(),
std::is_enum<T>());
}
if (ABSL_PREDICT_FALSE(!Contains(ArgumentToConv<T>(),
spec.conversion_char()))) {
return false;
}
return str_format_internal::FormatConvertImpl(
Manager<T>::Value(arg), spec,
static_cast<FormatSinkImpl*>(out))
.value;
}
Data data_;
Dispatcher dispatcher_;
};
#define ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(T, E) \
E template bool FormatArgImpl::Dispatch<T>(Data, FormatConversionSpecImpl, \
void*)
#define ABSL_INTERNAL_FORMAT_DISPATCH_OVERLOADS_EXPAND_(...) \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(str_format_internal::VoidPtr, \
__VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(bool, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(char, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(signed char, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(unsigned char, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(short, __VA_ARGS__); /* NOLINT */ \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(unsigned short, /* NOLINT */ \
__VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(int, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(unsigned int, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(long, __VA_ARGS__); /* NOLINT */ \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(unsigned long, /* NOLINT */ \
__VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(long long, /* NOLINT */ \
__VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(unsigned long long, /* NOLINT */ \
__VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(int128, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(uint128, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(float, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(double, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(long double, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(const char*, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(std::string, __VA_ARGS__); \
ABSL_INTERNAL_FORMAT_DISPATCH_INSTANTIATE_(string_view, __VA_ARGS__)
ABSL_INTERNAL_FORMAT_DISPATCH_OVERLOADS_EXPAND_(extern);
} // namespace str_format_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_STR_FORMAT_ARG_H_