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#pragma once
/**
* @file
*
* Template implementations (as opposed to mere declarations).
*
* This file is an exmample of the "impl.hh" pattern. See the
* contributing guide.
*
* One only needs to include this when one is declaring a
* `BaseClass<CustomType>` setting, or as derived class of such an
* instantiation.
*/
#include "config.hh"
namespace nix {
template<> struct BaseSetting<Strings>::trait
{
static constexpr bool appendable = true;
};
template<> struct BaseSetting<StringSet>::trait
{
static constexpr bool appendable = true;
};
template<> struct BaseSetting<StringMap>::trait
{
static constexpr bool appendable = true;
};
template<> struct BaseSetting<std::set<ExperimentalFeature>>::trait
{
static constexpr bool appendable = true;
};
template<typename T>
struct BaseSetting<T>::trait
{
static constexpr bool appendable = false;
};
template<typename T>
bool BaseSetting<T>::isAppendable()
{
return trait::appendable;
}
template<> void BaseSetting<Strings>::appendOrSet(Strings && newValue, bool append);
template<> void BaseSetting<StringSet>::appendOrSet(StringSet && newValue, bool append);
template<> void BaseSetting<StringMap>::appendOrSet(StringMap && newValue, bool append);
template<> void BaseSetting<std::set<ExperimentalFeature>>::appendOrSet(std::set<ExperimentalFeature> && newValue, bool append);
template<typename T>
void BaseSetting<T>::appendOrSet(T && newValue, bool append)
{
static_assert(
!trait::appendable,
"using default `appendOrSet` implementation with an appendable type");
assert(!append);
value = std::move(newValue);
}
template<typename T>
void BaseSetting<T>::set(const std::string & str, bool append)
{
if (experimentalFeatureSettings.isEnabled(experimentalFeature))
appendOrSet(parse(str), append);
else {
assert(experimentalFeature);
warn("Ignoring setting '%s' because experimental feature '%s' is not enabled",
name,
showExperimentalFeature(*experimentalFeature));
}
}
template<> void BaseSetting<bool>::convertToArg(Args & args, const std::string & category);
template<typename T>
void BaseSetting<T>::convertToArg(Args & args, const std::string & category)
{
args.addFlag({
.longName = name,
.description = fmt("Set the `%s` setting.", name),
.category = category,
.labels = {"value"},
.handler = {[this](std::string s) { overridden = true; set(s); }},
.experimentalFeature = experimentalFeature,
});
if (isAppendable())
args.addFlag({
.longName = "extra-" + name,
.description = fmt("Append to the `%s` setting.", name),
.category = category,
.labels = {"value"},
.handler = {[this](std::string s) { overridden = true; set(s, true); }},
.experimentalFeature = experimentalFeature,
});
}
#define DECLARE_CONFIG_SERIALISER(TY) \
template<> TY BaseSetting< TY >::parse(const std::string & str) const; \
template<> std::string BaseSetting< TY >::to_string() const;
DECLARE_CONFIG_SERIALISER(std::string)
DECLARE_CONFIG_SERIALISER(std::optional<std::string>)
DECLARE_CONFIG_SERIALISER(bool)
DECLARE_CONFIG_SERIALISER(Strings)
DECLARE_CONFIG_SERIALISER(StringSet)
DECLARE_CONFIG_SERIALISER(StringMap)
DECLARE_CONFIG_SERIALISER(std::set<ExperimentalFeature>)
template<typename T>
T BaseSetting<T>::parse(const std::string & str) const
{
static_assert(std::is_integral<T>::value, "Integer required.");
if (auto n = string2Int<T>(str))
return *n;
else
throw UsageError("setting '%s' has invalid value '%s'", name, str);
}
template<typename T>
std::string BaseSetting<T>::to_string() const
{
static_assert(std::is_integral<T>::value, "Integer required.");
return std::to_string(value);
}
}
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