liblangutil: refactor SourceReferenceFormatter, splitting out retrieval and making use of new SourceLocation's CharStream knowledge

liblangutil/SourceReferenceExtractor.cpp

@@ -0,0 +1,89 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <liblangutil/SourceReferenceExtractor.h>
+#include <liblangutil/CharStream.h>
+#include <liblangutil/Exceptions.h>
+
+#include <cmath>
+#include <iomanip>
+
+using namespace std;
+using namespace dev;
+using namespace langutil;
+
+SourceReferenceExtractor::Message SourceReferenceExtractor::extract(Exception const& _exception, string _category)
+{
+	SourceLocation const* location = boost::get_error_info<errinfo_sourceLocation>(_exception);
+
+	string const* message = boost::get_error_info<errinfo_comment>(_exception);
+	SourceReference primary = extract(location, message ? *message : "");
+
+	std::vector<SourceReference> secondary;
+	auto secondaryLocation = boost::get_error_info<errinfo_secondarySourceLocation>(_exception);
+	if (secondaryLocation && !secondaryLocation->infos.empty())
+		for (auto const& info: secondaryLocation->infos)
+			secondary.emplace_back(extract(&info.second, info.first));
+
+	return Message{std::move(primary), _category, std::move(secondary)};
+}
+
+SourceReference SourceReferenceExtractor::extract(SourceLocation const* _location, std::string message)
+{
+	if (!_location || !_location->source.get()) // Nothing we can extract here
+		return SourceReference::MessageOnly(std::move(message));
+
+	shared_ptr<CharStream> const& source = _location->source;
+
+	LineColumn const interest = source->translatePositionToLineColumn(_location->start);
+	LineColumn start = interest;
+	LineColumn end = source->translatePositionToLineColumn(_location->end);
+	bool const isMultiline = start.line != end.line;
+
+	string line = source->lineAtPosition(_location->start);
+
+	int locationLength = isMultiline ? line.length() - start.column : end.column - start.column;
+	if (locationLength > 150)
+	{
+		line = line.substr(0, start.column + 35) + " ... " + line.substr(end.column - 35);
+		end.column = start.column + 75;
+		locationLength = 75;
+	}
+
+	if (line.length() > 150)
+	{
+		int const len = line.length();
+		line = line.substr(max(0, start.column - 35), min(start.column, 35) + min(locationLength + 35, len - start.column));
+		if (start.column + locationLength + 35 < len)
+			line += " ...";
+		if (start.column > 35)
+		{
+			line = " ... " + line;
+			start.column = 40;
+		}
+		end.column = start.column + locationLength;
+	}
+
+	return SourceReference{
+		std::move(message),
+		source->name(),
+		interest,
+		isMultiline,
+		line,
+		start.column,
+		end.column,
+	};
+}