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AK: Make JSON parser return ErrorOr<JsonValue> (instead of Optional)

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Also add slightly richer parse errors now that we can include a string
literal with returned errors.

This will allow us to use TRY() when working with JSON data.
This commit is contained in:
Andreas Kling 2021-11-15 01:46:51 +01:00
parent 304c03f457
commit 587f9af960
54 changed files with 172 additions and 228 deletions
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101
AK/JsonParser.cpp
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@ -16,10 +16,10 @@ constexpr bool is_space(int ch)
return ch == '\t' || ch == '\n' || ch == '\r' || ch == ' ';
}
String JsonParser::consume_and_unescape_string()
ErrorOr<String> JsonParser::consume_and_unescape_string()
{
if (!consume_specific('"'))
return {};
return Error::from_string_literal("JsonParser: Expected '\"'"sv);
StringBuilder final_sb;
for (;;) {
@ -32,7 +32,7 @@ String JsonParser::consume_and_unescape_string()
if (ch == '"' || ch == '\\')
break;
if (is_ascii_c0_control(ch))
return {};
return Error::from_string_literal("JsonParser: Error while parsing string"sv);
++peek_index;
}
@ -101,97 +101,90 @@ String JsonParser::consume_and_unescape_string()
if (next_is('u')) {
ignore();
if (tell_remaining() < 4)
return {};
return Error::from_string_literal("JsonParser: EOF while parsing Unicode escape"sv);
auto code_point = AK::StringUtils::convert_to_uint_from_hex(consume(4));
if (code_point.has_value()) {
final_sb.append_code_point(code_point.value());
continue;
} else {
return {};
}
return Error::from_string_literal("JsonParser: Error while parsing Unicode escape"sv);
}
return {};
return Error::from_string_literal("JsonParser: Error while parsing string"sv);
}
if (!consume_specific('"'))
return {};
return Error::from_string_literal("JsonParser: Expected '\"'"sv);
return final_sb.to_string();
}
Optional<JsonValue> JsonParser::parse_object()
ErrorOr<JsonValue> JsonParser::parse_object()
{
JsonObject object;
if (!consume_specific('{'))
return {};
return Error::from_string_literal("JsonParser: Expected '{'"sv);
for (;;) {
ignore_while(is_space);
if (peek() == '}')
break;
ignore_while(is_space);
auto name = consume_and_unescape_string();
auto name = TRY(consume_and_unescape_string());
if (name.is_null())
return {};
return Error::from_string_literal("JsonParser: Expected object property name"sv);
ignore_while(is_space);
if (!consume_specific(':'))
return {};
return Error::from_string_literal("JsonParser: Expected ':'"sv);
ignore_while(is_space);
auto value = parse_helper();
if (!value.has_value())
return {};
object.set(name, value.release_value());
auto value = TRY(parse_helper());
object.set(name, move(value));
ignore_while(is_space);
if (peek() == '}')
break;
if (!consume_specific(','))
return {};
return Error::from_string_literal("JsonParser: Expected ','"sv);
ignore_while(is_space);
if (peek() == '}')
return {};
return Error::from_string_literal("JsonParser: Unexpected '}'"sv);
}
if (!consume_specific('}'))
return {};
return Error::from_string_literal("JsonParser: Expected '}'"sv);
return JsonValue { move(object) };
}
Optional<JsonValue> JsonParser::parse_array()
ErrorOr<JsonValue> JsonParser::parse_array()
{
JsonArray array;
if (!consume_specific('['))
return {};
return Error::from_string_literal("JsonParser: Expected '['"sv);
for (;;) {
ignore_while(is_space);
if (peek() == ']')
break;
auto element = parse_helper();
if (!element.has_value())
return {};
array.append(element.release_value());
auto element = TRY(parse_helper());
array.append(move(element));
ignore_while(is_space);
if (peek() == ']')
break;
if (!consume_specific(','))
return {};
return Error::from_string_literal("JsonParser: Expected ','"sv);
ignore_while(is_space);
if (peek() == ']')
return {};
return Error::from_string_literal("JsonParser: Unexpected ']'"sv);
}
ignore_while(is_space);
if (!consume_specific(']'))
return {};
return Error::from_string_literal("JsonParser: Expected ']'"sv);
return JsonValue { move(array) };
}
Optional<JsonValue> JsonParser::parse_string()
ErrorOr<JsonValue> JsonParser::parse_string()
{
auto result = consume_and_unescape_string();
if (result.is_null())
return {};
return JsonValue(result);
auto string = TRY(consume_and_unescape_string());
return JsonValue(move(string));
}
Optional<JsonValue> JsonParser::parse_number()
ErrorOr<JsonValue> JsonParser::parse_number()
{
JsonValue value;
Vector<char, 128> number_buffer;
@ -202,7 +195,7 @@ Optional<JsonValue> JsonParser::parse_number()
char ch = peek();
if (ch == '.') {
if (is_double)
return {};
return Error::from_string_literal("JsonParser: Multiple '.' in number"sv);
is_double = true;
++m_index;
@ -211,18 +204,18 @@ Optional<JsonValue> JsonParser::parse_number()
if (ch == '-' || (ch >= '0' && ch <= '9')) {
if (is_double) {
if (ch == '-')
return {};
return Error::from_string_literal("JsonParser: Error while parsing number"sv);
fraction_buffer.append(ch);
} else {
if (number_buffer.size() > 0) {
if (number_buffer.at(0) == '0')
return {};
return Error::from_string_literal("JsonParser: Error while parsing number"sv);
}
if (number_buffer.size() > 1) {
if (number_buffer.at(0) == '-' && number_buffer.at(1) == '0')
return {};
return Error::from_string_literal("JsonParser: Error while parsing number"sv);
}
number_buffer.append(ch);
@ -245,14 +238,14 @@ Optional<JsonValue> JsonParser::parse_number()
} else {
auto number = number_string.to_int();
if (!number.has_value())
return {};
return Error::from_string_literal("JsonParser: Error while parsing number"sv);
whole = number.value();
}
StringView fraction_string(fraction_buffer.data(), fraction_buffer.size());
auto fraction_string_uint = fraction_string.to_uint();
if (!fraction_string_uint.has_value())
return {};
return Error::from_string_literal("JsonParser: Error while parsing number"sv);
int fraction = fraction_string_uint.value();
fraction *= (whole < 0) ? -1 : 1;
@ -273,7 +266,7 @@ Optional<JsonValue> JsonParser::parse_number()
} else {
auto number = number_string.to_int<i64>();
if (!number.has_value())
return {};
return Error::from_string_literal("JsonParser: Error while parsing number"sv);
if (number.value() <= NumericLimits<i32>::max()) {
value = JsonValue((i32)number.value());
} else {
@ -287,28 +280,28 @@ Optional<JsonValue> JsonParser::parse_number()
return value;
}
Optional<JsonValue> JsonParser::parse_true()
ErrorOr<JsonValue> JsonParser::parse_true()
{
if (!consume_specific("true"))
return {};
return Error::from_string_literal("JsonParser: Expected 'true'"sv);
return JsonValue(true);
}
Optional<JsonValue> JsonParser::parse_false()
ErrorOr<JsonValue> JsonParser::parse_false()
{
if (!consume_specific("false"))
return {};
return Error::from_string_literal("JsonParser: Expected 'false'"sv);
return JsonValue(false);
}
Optional<JsonValue> JsonParser::parse_null()
ErrorOr<JsonValue> JsonParser::parse_null()
{
if (!consume_specific("null"))
return {};
return Error::from_string_literal("JsonParser: Expected 'null'"sv);
return JsonValue(JsonValue::Type::Null);
}
Optional<JsonValue> JsonParser::parse_helper()
ErrorOr<JsonValue> JsonParser::parse_helper()
{
ignore_while(is_space);
auto type_hint = peek();
@ -339,17 +332,15 @@ Optional<JsonValue> JsonParser::parse_helper()
return parse_null();
}
return {};
return Error::from_string_literal("JsonParser: Unexpected character"sv);
}
Optional<JsonValue> JsonParser::parse()
ErrorOr<JsonValue> JsonParser::parse()
{
auto result = parse_helper();
if (!result.has_value())
return {};
auto result = TRY(parse_helper());
ignore_while(is_space);
if (!is_eof())
return {};
return Error::from_string_literal("JsonParser: Didn't consume all input"sv);
return result;
}