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