lix/src/libexpr/value-to-json.cc
pennae 6526d1676b replace most Pos objects/ptrs with indexes into a position table
Pos objects are somewhat wasteful as they duplicate the origin file name and
input type for each object. on files that produce more than one Pos when parsed
this a sizeable waste of memory (one pointer per Pos). the same goes for
ptr<Pos> on 64 bit machines: parsing enough source to require 8 bytes to locate
a position would need at least 8GB of input and 64GB of expression memory. it's
not likely that we'll hit that any time soon, so we can use a uint32_t index to
locate positions instead.
2022-04-21 21:46:06 +02:00

107 lines
2.8 KiB
C++

#include "value-to-json.hh"
#include "json.hh"
#include "eval-inline.hh"
#include "util.hh"
#include <cstdlib>
#include <iomanip>
namespace nix {
void printValueAsJSON(EvalState & state, bool strict,
Value & v, const PosIdx pos, JSONPlaceholder & out, PathSet & context)
{
checkInterrupt();
if (strict) state.forceValue(v, pos);
switch (v.type()) {
case nInt:
out.write(v.integer);
break;
case nBool:
out.write(v.boolean);
break;
case nString:
copyContext(v, context);
out.write(v.string.s);
break;
case nPath:
out.write(state.copyPathToStore(context, v.path));
break;
case nNull:
out.write(nullptr);
break;
case nAttrs: {
auto maybeString = state.tryAttrsToString(pos, v, context, false, false);
if (maybeString) {
out.write(*maybeString);
break;
}
auto i = v.attrs->find(state.sOutPath);
if (i == v.attrs->end()) {
auto obj(out.object());
StringSet names;
for (auto & j : *v.attrs)
names.insert(j.name);
for (auto & j : names) {
Attr & a(*v.attrs->find(state.symbols.create(j)));
auto placeholder(obj.placeholder(j));
printValueAsJSON(state, strict, *a.value, a.pos, placeholder, context);
}
} else
printValueAsJSON(state, strict, *i->value, i->pos, out, context);
break;
}
case nList: {
auto list(out.list());
for (auto elem : v.listItems()) {
auto placeholder(list.placeholder());
printValueAsJSON(state, strict, *elem, pos, placeholder, context);
}
break;
}
case nExternal:
v.external->printValueAsJSON(state, strict, out, context);
break;
case nFloat:
out.write(v.fpoint);
break;
case nThunk:
case nFunction:
auto e = TypeError({
.msg = hintfmt("cannot convert %1% to JSON", showType(v)),
.errPos = state.positions[v.determinePos(pos)]
});
e.addTrace(state.positions[pos], hintfmt("message for the trace"));
throw e;
}
}
void printValueAsJSON(EvalState & state, bool strict,
Value & v, const PosIdx pos, std::ostream & str, PathSet & context)
{
JSONPlaceholder out(str);
printValueAsJSON(state, strict, v, pos, out, context);
}
void ExternalValueBase::printValueAsJSON(EvalState & state, bool strict,
JSONPlaceholder & out, PathSet & context) const
{
throw TypeError("cannot convert %1% to JSON", showType());
}
}