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Diffstat (limited to 'src/libexpr/json-to-value.cc')
| -rw-r--r-- | src/libexpr/json-to-value.cc | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/src/libexpr/json-to-value.cc b/src/libexpr/json-to-value.cc new file mode 100644 index 000000000000..1892b0bac1af --- /dev/null +++ b/src/libexpr/json-to-value.cc @@ -0,0 +1,149 @@ +#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.list.elems[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 == '-') { + bool neg = false; + if (*s == '-') { + neg = true; + if (!*++s) throw JSONParseError("unexpected end of JSON number"); + } + NixInt n = 0; + // FIXME: detect overflow + while (isdigit(*s)) n = n * 10 + (*s++ - '0'); + if (*s == '.' || *s == 'e') throw JSONParseError("floating point JSON numbers are not supported"); + mkInt(v, neg ? -n : n); + } + + 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); +} + + +} |