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#include "libexpr/json-to-value.hh"
#include <cstring>
namespace nix {
static void skipWhitespace(const char*& s) {
while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r') {
s++;
}
}
static std::string parseJSONString(const char*& s) {
std::string res;
if (*s++ != '"') {
throw JSONParseError("expected JSON string");
}
while (*s != '"') {
if (*s == 0) {
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 == 0) {
throw JSONParseError("expected JSON value");
}
if (*s == '[') {
s++;
NixList values;
values.reserve(128);
skipWhitespace(s);
while (true) {
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.list)[n] = values[n];
}
}
else if (*s == '{') {
s++;
ValueMap attrs;
while (true) {
skipWhitespace(s);
if (attrs.empty() && *s == '}') {
break;
}
std::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));
}
s++;
}
else if (*s == '"') {
mkString(v, parseJSONString(s));
}
else if ((isdigit(*s) != 0) || *s == '-' || *s == '.') {
// Buffer into a std::string first, then use built-in C++ conversions
std::string tmp_number;
ValueType number_type = tInt;
while ((isdigit(*s) != 0) || *s == '-' || *s == '.' || *s == 'e' ||
*s == 'E') {
if (*s == '.' || *s == 'e' || *s == 'E') {
number_type = tFloat;
}
tmp_number += *s++;
}
try {
if (number_type == tFloat) {
mkFloat(v, stod(tmp_number));
} else {
mkInt(v, stol(tmp_number));
}
} catch (std::invalid_argument& e) {
throw JSONParseError("invalid JSON number");
} catch (std::out_of_range& e) {
throw JSONParseError("out-of-range JSON 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 std::string& s_, Value& v) {
const char* s = s_.c_str();
parseJSON(state, s, v);
skipWhitespace(s);
if (*s != 0) {
throw JSONParseError(
format("expected end-of-string while parsing JSON value: %1%") % s);
}
}
} // namespace nix
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