lix-releng-staging/src/libexpr/value-to-json.cc
Eelco Dolstra b83801f8b3 Optimize small lists
The value pointers of lists with 1 or 2 elements are now stored in the
list value itself. In particular, this makes the "concatMap (x: if
cond then [(f x)] else [])" idiom cheaper.
2015-07-23 22:05:09 +02:00

101 lines
2.6 KiB
C++

#include "value-to-json.hh"
#include "eval-inline.hh"
#include "util.hh"
#include <cstdlib>
#include <iomanip>
namespace nix {
void escapeJSON(std::ostream & str, const string & s)
{
str << "\"";
for (auto & i : s)
if (i == '\"' || i == '\\') str << "\\" << i;
else if (i == '\n') str << "\\n";
else if (i == '\r') str << "\\r";
else if (i == '\t') str << "\\t";
else if (i >= 0 && i < 32)
str << "\\u" << std::setfill('0') << std::setw(4) << std::hex << (uint16_t) i << std::dec;
else str << i;
str << "\"";
}
void printValueAsJSON(EvalState & state, bool strict,
Value & v, std::ostream & str, PathSet & context)
{
checkInterrupt();
if (strict) state.forceValue(v);
switch (v.type) {
case tInt:
str << v.integer;
break;
case tBool:
str << (v.boolean ? "true" : "false");
break;
case tString:
copyContext(v, context);
escapeJSON(str, v.string.s);
break;
case tPath:
escapeJSON(str, state.copyPathToStore(context, v.path));
break;
case tNull:
str << "null";
break;
case tAttrs: {
Bindings::iterator i = v.attrs->find(state.sOutPath);
if (i == v.attrs->end()) {
JSONObject json(str);
StringSet names;
for (auto & j : *v.attrs)
names.insert(j.name);
for (auto & j : names) {
Attr & a(*v.attrs->find(state.symbols.create(j)));
json.attr(j);
printValueAsJSON(state, strict, *a.value, str, context);
}
} else
printValueAsJSON(state, strict, *i->value, str, context);
break;
}
case tList1: case tList2: case tListN: {
JSONList json(str);
for (unsigned int n = 0; n < v.listSize(); ++n) {
json.elem();
printValueAsJSON(state, strict, *v.listElems()[n], str, context);
}
break;
}
case tExternal:
v.external->printValueAsJSON(state, strict, str, context);
break;
default:
throw TypeError(format("cannot convert %1% to JSON") % showType(v));
}
}
void ExternalValueBase::printValueAsJSON(EvalState & state, bool strict,
std::ostream & str, PathSet & context) const
{
throw TypeError(format("cannot convert %1% to JSON") % showType());
}
}