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#include "value/context.hh"
#include <optional>
namespace nix {
NixStringContextElem NixStringContextElem::parse(
std::string_view s0,
const ExperimentalFeatureSettings & xpSettings)
{
std::string_view s = s0;
std::function<SingleDerivedPath()> parseRest;
parseRest = [&]() -> SingleDerivedPath {
// Case on whether there is a '!'
size_t index = s.find("!");
if (index == std::string_view::npos) {
return SingleDerivedPath::Opaque {
.path = StorePath { s },
};
} else {
std::string output { s.substr(0, index) };
// Advance string to parse after the '!'
s = s.substr(index + 1);
auto drv = make_ref<SingleDerivedPath>(parseRest());
drvRequireExperiment(*drv, xpSettings);
return SingleDerivedPath::Built {
.drvPath = std::move(drv),
.output = std::move(output),
};
}
};
if (s.size() == 0) {
throw BadNixStringContextElem(s0,
"String context element should never be an empty string");
}
switch (s.at(0)) {
case '!': {
// Advance string to parse after the '!'
s = s.substr(1);
// Find *second* '!'
if (s.find("!") == std::string_view::npos) {
throw BadNixStringContextElem(s0,
"String content element beginning with '!' should have a second '!'");
}
return std::visit(
[&](auto x) -> NixStringContextElem { return std::move(x); },
parseRest());
}
case '=': {
return NixStringContextElem::DrvDeep {
.drvPath = StorePath { s.substr(1) },
};
}
default: {
// Ensure no '!'
if (s.find("!") != std::string_view::npos) {
throw BadNixStringContextElem(s0,
"String content element not beginning with '!' should not have a second '!'");
}
return std::visit(
[&](auto x) -> NixStringContextElem { return std::move(x); },
parseRest());
}
}
}
std::string NixStringContextElem::to_string() const
{
std::string res;
std::function<void(const SingleDerivedPath &)> toStringRest;
toStringRest = [&](auto & p) {
std::visit(overloaded {
[&](const SingleDerivedPath::Opaque & o) {
res += o.path.to_string();
},
[&](const SingleDerivedPath::Built & o) {
res += o.output;
res += '!';
toStringRest(*o.drvPath);
},
}, p.raw());
};
std::visit(overloaded {
[&](const NixStringContextElem::Built & b) {
res += '!';
toStringRest(b);
},
[&](const NixStringContextElem::Opaque & o) {
toStringRest(o);
},
[&](const NixStringContextElem::DrvDeep & d) {
res += '=';
res += d.drvPath.to_string();
},
}, raw());
return res;
}
}
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