ladybird/Libraries/LibGUI/GMLParser.cpp
Andreas Kling 6e0976d858 LibGUI: Make the GML parser a bit more fault-tolerant
It will now fail and whine in the debug log instead of asserting.
2020-12-20 14:30:40 +01:00

153 lines
4.7 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/GenericLexer.h>
#include <AK/JsonObject.h>
#include <AK/JsonValue.h>
#include <LibGUI/GMLParser.h>
#include <ctype.h>
namespace GUI {
static bool is_valid_class_name_character(char ch)
{
return isalpha(ch) || ch == ':';
}
static bool is_valid_property_name_character(char ch)
{
return isalpha(ch) || ch == '_';
}
static void swallow_whitespace(GenericLexer& scanner)
{
scanner.consume_while([](auto ch) { return isspace(ch); });
}
static Optional<JsonValue> parse_core_object(GenericLexer& scanner)
{
JsonObject object;
JsonArray children;
// '@Foo' means new Core::Object of class Foo
if (!scanner.consume_specific('@')) {
dbgln("Expected '@'");
return {};
}
auto class_name = scanner.consume_while([](auto ch) { return is_valid_class_name_character(ch); });
object.set("class", JsonValue(class_name));
swallow_whitespace(scanner);
if (!scanner.consume_specific('{')) {
dbgln("Expected '{{'");
return {};
}
swallow_whitespace(scanner);
for (;;) {
swallow_whitespace(scanner);
if (scanner.peek() == '}') {
// End of object
break;
}
if (scanner.peek() == '@') {
// It's a child object.
auto value = parse_core_object(scanner);
if (!value.has_value())
return {};
if (!value.value().is_object()) {
dbgln("Expected child to be Core::Object");
return {};
}
children.append(value.release_value());
} else {
// It's a property.
auto property_name = scanner.consume_while([](auto ch) { return is_valid_property_name_character(ch); });
swallow_whitespace(scanner);
if (property_name.is_empty()) {
dbgln("Expected non-empty property name");
return {};
}
if (!scanner.consume_specific(':')) {
dbgln("Expected ':'");
return {};
}
swallow_whitespace(scanner);
JsonValue value;
if (scanner.peek() == '@') {
auto parsed_value = parse_core_object(scanner);
if (!parsed_value.has_value())
return {};
if (!parsed_value.value().is_object()) {
dbgln("Expected property to be Core::Object");
return {};
}
value = parsed_value.release_value();
} else {
auto value_string = scanner.consume_line();
auto parsed_value = JsonValue::from_string(value_string);
if (!parsed_value.has_value()) {
dbgln("Expected property to be JSON value");
return {};
}
value = parsed_value.release_value();
}
object.set(property_name, move(value));
}
}
if (!scanner.consume_specific('}')) {
dbgln("Expected '}'");
return {};
}
if (!children.is_empty())
object.set("children", move(children));
return object;
}
JsonValue parse_gml(const StringView& string)
{
GenericLexer scanner(string);
auto root = parse_core_object(scanner);
if (!root.has_value())
return JsonValue();
return root.release_value();
}
}