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merge(3p/abseil_cpp): Merge upstream at 'ccdbb5941'

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Change-Id: I6e85fc7b5f76bba1f1eef15e600a8acb64e97ef5
This commit is contained in:
Vincent Ambo 2020-06-17 14:53:11 +01:00
commit 543379ce45
97 changed files with 3546 additions and 2316 deletions
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119
third_party/abseil_cpp/absl/flags/internal/commandlineflag.h vendored
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@ -16,14 +16,8 @@
#ifndef ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_
#define ABSL_FLAGS_INTERNAL_COMMANDLINEFLAG_H_
#include <memory>
#include <string>
#include "absl/base/config.h"
#include "absl/base/internal/fast_type_id.h"
#include "absl/base/macros.h"
#include "absl/strings/string_view.h"
#include "absl/types/optional.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
@ -34,7 +28,7 @@ namespace flags_internal {
// cases this id is enough to uniquely identify the flag's value type. In a few
// cases we'll have to resort to using actual RTTI implementation if it is
// available.
using FlagFastTypeId = base_internal::FastTypeIdType;
using FlagFastTypeId = absl::base_internal::FastTypeIdType;
// Options that control SetCommandLineOptionWithMode.
enum FlagSettingMode {
@ -67,117 +61,6 @@ class FlagStateInterface {
virtual void Restore() const = 0;
};
// Holds all information for a flag.
class CommandLineFlag {
public:
constexpr CommandLineFlag() = default;
// Not copyable/assignable.
CommandLineFlag(const CommandLineFlag&) = delete;
CommandLineFlag& operator=(const CommandLineFlag&) = delete;
// Non-polymorphic access methods.
// Return true iff flag has type T.
template <typename T>
inline bool IsOfType() const {
return TypeId() == base_internal::FastTypeId<T>();
}
// Attempts to retrieve the flag value. Returns value on success,
// absl::nullopt otherwise.
template <typename T>
absl::optional<T> TryGet() const {
if (IsRetired() || !IsOfType<T>()) {
return absl::nullopt;
}
// Implementation notes:
//
// We are wrapping a union around the value of `T` to serve three purposes:
//
// 1. `U.value` has correct size and alignment for a value of type `T`
// 2. The `U.value` constructor is not invoked since U's constructor does
// not do it explicitly.
// 3. The `U.value` destructor is invoked since U's destructor does it
// explicitly. This makes `U` a kind of RAII wrapper around non default
// constructible value of T, which is destructed when we leave the
// scope. We do need to destroy U.value, which is constructed by
// CommandLineFlag::Read even though we left it in a moved-from state
// after std::move.
//
// All of this serves to avoid requiring `T` being default constructible.
union U {
T value;
U() {}
~U() { value.~T(); }
};
U u;
Read(&u.value);
return std::move(u.value);
}
// Polymorphic access methods
// Returns name of this flag.
virtual absl::string_view Name() const = 0;
// Returns name of the file where this flag is defined.
virtual std::string Filename() const = 0;
// Returns help message associated with this flag.
virtual std::string Help() const = 0;
// Returns true iff this object corresponds to retired flag.
virtual bool IsRetired() const;
virtual std::string DefaultValue() const = 0;
virtual std::string CurrentValue() const = 0;
// Sets the value of the flag based on specified string `value`. If the flag
// was successfully set to new value, it returns true. Otherwise, sets `error`
// to indicate the error, leaves the flag unchanged, and returns false.
bool ParseFrom(absl::string_view value, std::string* error);
protected:
~CommandLineFlag() = default;
private:
friend class PrivateHandleAccessor;
// Sets the value of the flag based on specified string `value`. If the flag
// was successfully set to new value, it returns true. Otherwise, sets `error`
// to indicate the error, leaves the flag unchanged, and returns false. There
// are three ways to set the flag's value:
// * Update the current flag value
// * Update the flag's default value
// * Update the current flag value if it was never set before
// The mode is selected based on `set_mode` parameter.
virtual bool ParseFrom(absl::string_view value,
flags_internal::FlagSettingMode set_mode,
flags_internal::ValueSource source,
std::string* error) = 0;
// Returns id of the flag's value type.
virtual FlagFastTypeId TypeId() const = 0;
// Interface to save flag to some persistent state. Returns current flag state
// or nullptr if flag does not support saving and restoring a state.
virtual std::unique_ptr<FlagStateInterface> SaveState() = 0;
// Copy-construct a new value of the flag's type in a memory referenced by
// the dst based on the current flag's value.
virtual void Read(void* dst) const = 0;
// To be deleted. Used to return true if flag's current value originated from
// command line.
virtual bool IsSpecifiedOnCommandLine() const = 0;
// Validates supplied value usign validator or parseflag routine
virtual bool ValidateInputValue(absl::string_view value) const = 0;
// Checks that flags default value can be converted to string and back to the
// flag's value type.
virtual void CheckDefaultValueParsingRoundtrip() const = 0;
};
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl