feat(tvix): builtins.fromJSON: use nlohmann/json parser instead of custom parser
backported from upstream at f1fac0b5c3b75efab781949fdff2b67ffdda2cb3 Change-Id: I788e3a9b930351118a5f248b356c351afd7f5391 Reviewed-on: https://cl.tvl.fyi/c/depot/+/2138 Tested-by: BuildkiteCI Reviewed-by: tazjin <mail@tazj.in>
This commit is contained in:
Yorick van Pelt
glittershark
parent
de44fdf92a
commit
b595553f63
1 changed files with 120 additions and 159 deletions
257
third_party/nix/src/libexpr/json-to-value.cc
vendored
257
third_party/nix/src/libexpr/json-to-value.cc
vendored
|
|
@ -1,185 +1,146 @@
|
|||
#include "libexpr/json-to-value.hh"
|
||||
|
||||
#include <cstring>
|
||||
#include <nlohmann/json.hpp>
|
||||
#include <variant>
|
||||
#include <vector>
|
||||
|
||||
#include "libexpr/value.hh"
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
namespace nix {
|
||||
|
||||
static void skipWhitespace(const char*& s) {
|
||||
while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r') {
|
||||
s++;
|
||||
}
|
||||
}
|
||||
// for more information, refer to
|
||||
// https://github.com/nlohmann/json/blob/master/include/nlohmann/detail/input/json_sax.hpp
|
||||
class JSONSax : nlohmann::json_sax<json> {
|
||||
class JSONState {
|
||||
protected:
|
||||
JSONState* parent;
|
||||
Value* v;
|
||||
|
||||
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;
|
||||
}
|
||||
public:
|
||||
virtual JSONState* resolve(EvalState&) {
|
||||
throw std::logic_error("tried to close toplevel json parser state");
|
||||
};
|
||||
explicit JSONState(JSONState* p) : parent(p), v(nullptr){};
|
||||
explicit JSONState(Value* v) : v(v){};
|
||||
JSONState(JSONState& p) = delete;
|
||||
Value& value(EvalState& state) {
|
||||
if (v == nullptr) v = state.allocValue();
|
||||
return *v;
|
||||
};
|
||||
virtual ~JSONState(){};
|
||||
virtual void add(){};
|
||||
};
|
||||
|
||||
static void parseJSON(EvalState& state, const char*& s, Value& v) {
|
||||
skipWhitespace(s);
|
||||
class JSONObjectState : public JSONState {
|
||||
using JSONState::JSONState;
|
||||
ValueMap attrs = ValueMap();
|
||||
virtual JSONState* resolve(EvalState& state) override {
|
||||
Value& v = parent->value(state);
|
||||
state.mkAttrs(v, attrs.size());
|
||||
for (auto& i : attrs) v.attrs->push_back(Attr(i.first, i.second));
|
||||
return parent;
|
||||
}
|
||||
virtual void add() override { v = nullptr; };
|
||||
|
||||
if (*s == 0) {
|
||||
throw JSONParseError("expected JSON value");
|
||||
public:
|
||||
void key(string_t& name, EvalState& state) {
|
||||
attrs[state.symbols.Create(name)] = &value(state);
|
||||
}
|
||||
};
|
||||
|
||||
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++;
|
||||
class JSONListState : public JSONState {
|
||||
std::vector<Value*> values;
|
||||
virtual JSONState* resolve(EvalState& state) override {
|
||||
Value& v = parent->value(state);
|
||||
state.mkList(v, values.size());
|
||||
for (size_t n = 0; n < values.size(); ++n) {
|
||||
(*v.list)[n] = values[n];
|
||||
}
|
||||
return parent;
|
||||
}
|
||||
|
||||
else if (*s == '{') {
|
||||
s++;
|
||||
ValueMap attrs;
|
||||
while (true) {
|
||||
skipWhitespace(s);
|
||||
if (attrs.empty() && *s == '}') {
|
||||
break;
|
||||
void add() override {
|
||||
values.push_back(v);
|
||||
v = nullptr;
|
||||
};
|
||||
|
||||
public:
|
||||
JSONListState(JSONState* p, std::size_t reserve) : JSONState(p) {
|
||||
values.reserve(reserve);
|
||||
}
|
||||
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++;
|
||||
};
|
||||
|
||||
EvalState& state;
|
||||
JSONState* rs;
|
||||
|
||||
template <typename T, typename... Args>
|
||||
inline bool handle_value(T f, Args... args) {
|
||||
f(rs->value(state), args...);
|
||||
rs->add();
|
||||
return true;
|
||||
}
|
||||
|
||||
else if (*s == '"') {
|
||||
mkString(v, parseJSONString(s));
|
||||
public:
|
||||
JSONSax(EvalState& state, Value& v) : state(state), rs(new JSONState(&v)){};
|
||||
~JSONSax() { delete rs; };
|
||||
|
||||
bool null() { return handle_value(mkNull); }
|
||||
|
||||
bool boolean(bool val) { return handle_value(mkBool, val); }
|
||||
|
||||
bool number_integer(number_integer_t val) { return handle_value(mkInt, val); }
|
||||
|
||||
bool number_unsigned(number_unsigned_t val) {
|
||||
return handle_value(mkInt, val);
|
||||
}
|
||||
|
||||
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++;
|
||||
bool number_float(number_float_t val, const string_t& s) {
|
||||
return handle_value(mkFloat, val);
|
||||
}
|
||||
|
||||
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");
|
||||
}
|
||||
bool string(string_t& val) {
|
||||
return handle_value<void(Value&, const char*)>(mkString, val.c_str());
|
||||
}
|
||||
|
||||
else if (strncmp(s, "true", 4) == 0) {
|
||||
s += 4;
|
||||
mkBool(v, true);
|
||||
bool start_object(std::size_t len) {
|
||||
JSONState* old = rs;
|
||||
rs = new JSONObjectState(old);
|
||||
return true;
|
||||
}
|
||||
|
||||
else if (strncmp(s, "false", 5) == 0) {
|
||||
s += 5;
|
||||
mkBool(v, false);
|
||||
bool key(string_t& name) {
|
||||
dynamic_cast<JSONObjectState*>(rs)->key(name, state);
|
||||
return true;
|
||||
}
|
||||
|
||||
else if (strncmp(s, "null", 4) == 0) {
|
||||
s += 4;
|
||||
mkNull(v);
|
||||
bool end_object() {
|
||||
JSONState* old = rs;
|
||||
rs = old->resolve(state);
|
||||
delete old;
|
||||
rs->add();
|
||||
return true;
|
||||
}
|
||||
|
||||
else {
|
||||
throw JSONParseError("unrecognised JSON value");
|
||||
bool end_array() { return end_object(); }
|
||||
|
||||
bool start_array(size_t len) {
|
||||
JSONState* old = rs;
|
||||
rs = new JSONListState(
|
||||
old, len != std::numeric_limits<size_t>::max() ? len : 128);
|
||||
return true;
|
||||
}
|
||||
|
||||
bool parse_error(std::size_t, const std::string&,
|
||||
const nlohmann::detail::exception& ex) {
|
||||
throw JSONParseError(ex.what());
|
||||
}
|
||||
};
|
||||
|
||||
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);
|
||||
JSONSax parser(state, v);
|
||||
bool res = json::sax_parse(s_, &parser);
|
||||
if (!res) throw JSONParseError("Invalid JSON Value");
|
||||
}
|
||||
}
|
||||
|
||||
} // namespace nix
|
||||
|
|
|
|||
Loading…
Reference in a new issue