formatSource method
- SourceCode source
Formats the given source
.
Returns a new SourceCode containing the formatted code and the resulting selection, if any.
Implementation
SourceCode formatSource(SourceCode source) {
// Enable all features that are enabled by default in the current analyzer
// version.
// TODO(paulberry): consider plumbing in experiment enable flags from the
// command line.
var featureSet = FeatureSet.fromEnableFlags2(
sdkLanguageVersion: Version(2, 10, 0), flags: ['non-nullable']);
var inputOffset = 0;
var text = source.text;
var unitSourceCode = source;
if (!source.isCompilationUnit) {
var prefix = 'void foo() { ';
inputOffset = prefix.length;
text = '$prefix$text }';
unitSourceCode = SourceCode(
text,
uri: source.uri,
isCompilationUnit: false,
selectionStart: source.selectionStart != null
? source.selectionStart + inputOffset
: null,
selectionLength: source.selectionLength,
);
}
// Parse it.
var parseResult = parseString(
content: text,
featureSet: featureSet,
path: source.uri,
throwIfDiagnostics: false,
);
// Infer the line ending if not given one. Do it here since now we know
// where the lines start.
if (lineEnding == null) {
// If the first newline is "\r\n", use that. Otherwise, use "\n".
var lineStarts = parseResult.lineInfo.lineStarts;
if (lineStarts.length > 1 &&
lineStarts[1] >= 2 &&
text[lineStarts[1] - 2] == '\r') {
lineEnding = '\r\n';
} else {
lineEnding = '\n';
}
}
// Throw if there are syntactic errors.
var syntacticErrors = parseResult.errors.where((error) {
return error.errorCode.type == ErrorType.SYNTACTIC_ERROR;
}).toList();
if (syntacticErrors.isNotEmpty) {
throw FormatterException(syntacticErrors);
}
AstNode node;
if (source.isCompilationUnit) {
node = parseResult.unit;
} else {
var function = parseResult.unit.declarations[0] as FunctionDeclaration;
var body = function.functionExpression.body as BlockFunctionBody;
node = body.block.statements[0];
// Make sure we consumed all of the source.
var token = node.endToken.next;
if (token.type != TokenType.CLOSE_CURLY_BRACKET) {
var stringSource = StringSource(text, source.uri);
var error = AnalysisError(
stringSource,
token.offset - inputOffset,
math.max(token.length, 1),
ParserErrorCode.UNEXPECTED_TOKEN,
[token.lexeme]);
throw FormatterException([error]);
}
}
// Format it.
var lineInfo = parseResult.lineInfo;
var visitor = SourceVisitor(this, lineInfo, unitSourceCode);
var output = visitor.run(node);
// Sanity check that only whitespace was changed if that's all we expect.
if (fixes.isEmpty &&
!string_compare.equalIgnoringWhitespace(source.text, output.text)) {
throw UnexpectedOutputException(source.text, output.text);
}
return output;
}