lix/src/libexpr/json-to-value.cc

155 lines
4.2 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#include "config.h"
#include "json-to-value.hh"
#include <cstring>
namespace nix {
static void skipWhitespace(const char * & s)
{
while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r') s++;
}
#if HAVE_BOEHMGC
typedef std::vector<Value *, gc_allocator<Value *> > ValueVector;
typedef std::map<Symbol, Value *, std::less<Symbol>, gc_allocator<Value *> > ValueMap;
#else
typedef std::vector<Value *> ValueVector;
typedef std::map<Symbol, Value *> ValueMap;
#endif
static string parseJSONString(const char * & s)
{
string res;
if (*s++ != '"') throw JSONParseError("expected JSON string");
while (*s != '"') {
if (!*s) throw JSONParseError("got end-of-string in JSON string");
if (*s == '\\') {
s++;
if (*s == '"') res += '"';
else if (*s == '\\') res += '\\';
else if (*s == '/') res += '/';
else if (*s == '/') res += '/';
else if (*s == 'b') res += '\b';
else if (*s == 'f') res += '\f';
else if (*s == 'n') res += '\n';
else if (*s == 'r') res += '\r';
else if (*s == 't') res += '\t';
else if (*s == 'u') throw JSONParseError("\\u characters in JSON strings are currently not supported");
else throw JSONParseError("invalid escaped character in JSON string");
s++;
} else
res += *s++;
}
s++;
return res;
}
static void parseJSON(EvalState & state, const char * & s, Value & v)
{
skipWhitespace(s);
if (!*s) throw JSONParseError("expected JSON value");
if (*s == '[') {
s++;
ValueVector values;
values.reserve(128);
skipWhitespace(s);
while (1) {
if (values.empty() && *s == ']') break;
Value * v2 = state.allocValue();
parseJSON(state, s, *v2);
values.push_back(v2);
skipWhitespace(s);
if (*s == ']') break;
if (*s != ',') throw JSONParseError("expected , or ] after JSON array element");
s++;
}
s++;
state.mkList(v, values.size());
for (size_t n = 0; n < values.size(); ++n)
v.listElems()[n] = values[n];
}
else if (*s == '{') {
s++;
ValueMap attrs;
while (1) {
skipWhitespace(s);
if (attrs.empty() && *s == '}') break;
string name = parseJSONString(s);
skipWhitespace(s);
if (*s != ':') throw JSONParseError("expected : in JSON object");
s++;
Value * v2 = state.allocValue();
parseJSON(state, s, *v2);
attrs[state.symbols.create(name)] = v2;
skipWhitespace(s);
if (*s == '}') break;
if (*s != ',') throw JSONParseError("expected , or } after JSON member");
s++;
}
state.mkAttrs(v, attrs.size());
for (auto & i : attrs)
v.attrs->push_back(Attr(i.first, i.second));
v.attrs->sort();
s++;
}
else if (*s == '"') {
mkString(v, parseJSONString(s));
}
else if (isdigit(*s) || *s == '-' || *s == '.' ) {
// Buffer into a string first, then use built-in C++ conversions
std::string tmp_number;
ValueType number_type = tInt;
while (isdigit(*s) || *s == '-' || *s == '.' || *s == 'e' || *s == 'E') {
if (*s == '.' || *s == 'e' || *s == 'E')
number_type = tFloat;
tmp_number.append(*s++, 1);
}
if (number_type == tFloat) {
mkFloat(v, stod(tmp_number));
} else {
mkInt(v, stoi(tmp_number));
}
}
else if (strncmp(s, "true", 4) == 0) {
s += 4;
mkBool(v, true);
}
else if (strncmp(s, "false", 5) == 0) {
s += 5;
mkBool(v, false);
}
else if (strncmp(s, "null", 4) == 0) {
s += 4;
mkNull(v);
}
else throw JSONParseError("unrecognised JSON value");
}
void parseJSON(EvalState & state, const string & s_, Value & v)
{
const char * s = s_.c_str();
parseJSON(state, s, v);
skipWhitespace(s);
if (*s) throw JSONParseError(format("expected end-of-string while parsing JSON value: %1%") % s);
}
}