public VariableInfo(
VariableSymbol variableSymbol,
VariableStyle variableStyle,
bool useAsReturnValue = false)
{
_variableSymbol = variableSymbol;
_variableStyle = variableStyle;
_useAsReturnValue = useAsReturnValue;
}
protected VariableInfo CreateFromSymbolCommon <T>(
Compilation compilation,
ISymbol symbol,
ITypeSymbol type,
VariableStyle style,
HashSet <int> nonNoisySyntaxKindSet) where T : SyntaxNode
{
switch (symbol)
{
case ILocalSymbol local:
return(new VariableInfo(
new LocalVariableSymbol <T>(compilation, local, type, nonNoisySyntaxKindSet),
style));
case IParameterSymbol parameter:
return(new VariableInfo(new ParameterVariableSymbol(compilation, parameter, type), style));
case IRangeVariableSymbol rangeVariable:
return(new VariableInfo(new QueryVariableSymbol(compilation, rangeVariable, type), style));
}
return(Contract.FailWithReturn <VariableInfo>(FeaturesResources.Unknown));
}
protected VariableStyle AlwaysReturn(VariableStyle style)
{
if (style == VariableStyle.InputOnly)
{
return(VariableStyle.Ref);
}
if (style == VariableStyle.MoveIn)
{
return(VariableStyle.Out);
}
if (style == VariableStyle.SplitIn)
{
return(VariableStyle.Out);
}
if (style == VariableStyle.SplitOut)
{
return(VariableStyle.OutWithMoveOut);
}
return(style);
}
private bool TryGetVariableStyle(
bool bestEffort,
Dictionary <ISymbol, List <SyntaxToken> > symbolMap,
ISymbol symbol,
SemanticModel model,
ITypeSymbol type,
bool captured,
bool dataFlowIn,
bool dataFlowOut,
bool alwaysAssigned,
bool variableDeclared,
bool readInside,
bool writtenInside,
bool readOutside,
bool writtenOutside,
bool unsafeAddressTaken,
out VariableStyle variableStyle)
{
Contract.ThrowIfNull(model);
Contract.ThrowIfNull(type);
if (!ExtractMethodMatrix.TryGetVariableStyle(
bestEffort, captured, dataFlowIn, dataFlowOut, alwaysAssigned, variableDeclared,
readInside, writtenInside, readOutside, writtenOutside, unsafeAddressTaken,
out variableStyle))
{
Contract.ThrowIfTrue(bestEffort, "Should never fail if bestEffort is true");
return(false);
}
if (SelectionContainsOnlyIdentifierWithSameType(type))
{
return(true);
}
if (UserDefinedValueType(model.Compilation, type) && !this.SelectionResult.DontPutOutOrRefOnStruct)
{
variableStyle = AlwaysReturn(variableStyle);
return(true);
}
// for captured variable, never try to move the decl into extracted method
if (captured && variableStyle == VariableStyle.MoveIn)
{
variableStyle = VariableStyle.Out;
return(true);
}
// check special value type cases
if (type.IsValueType && !IsWrittenInsideForFrameworkValueType(symbolMap, model, symbol, writtenInside))
{
return(true);
}
// don't blindly always return. make sure there is a write inside of the selection
if (this.SelectionResult.AllowMovingDeclaration || !writtenInside)
{
return(true);
}
variableStyle = AlwaysReturn(variableStyle);
return(true);
}
/// <summary> /// create VariableInfo type /// </summary> protected abstract VariableInfo CreateFromSymbol(Compilation compilation, ISymbol symbol, ITypeSymbol type, VariableStyle variableStyle, bool variableDeclared);
public static bool TryGetVariableStyle(
bool bestEffort,
bool captured,
bool dataFlowIn,
bool dataFlowOut,
bool alwaysAssigned,
bool variableDeclared,
bool readInside,
bool writtenInside,
bool readOutside,
bool writtenOutside,
bool unsafeAddressTaken,
out VariableStyle variableStyle)
{
// bug # 12258, 12114
// use "out" if "&" is taken for the variable
if (unsafeAddressTaken)
{
variableStyle = VariableStyle.Out;
return(true);
}
var key = new Key(
dataFlowIn,
dataFlowOut,
alwaysAssigned,
variableDeclared,
readInside,
writtenInside,
readOutside,
writtenOutside);
// special cases
if (!s_matrix.ContainsKey(key))
{
// Interesting case. Due to things like constant analysis there can be regions that
// the compiler considers data not to flow in (because analysis proves that that
// path will never be taken). However, the variable can still be read/written inside
// the region. For purposes of extract method, we check for this case, and we
// pretend it's as if data flowed into the region.
if (!dataFlowIn && (readInside || writtenInside))
{
key = new Key(true, dataFlowOut, alwaysAssigned, variableDeclared, readInside, writtenInside, readOutside, writtenOutside);
}
// another interesting case (bug # 10875)
// basically, it can happen in malformed code where a variable is not properly assigned but used outside of the selection + unreachable code region
// for such cases, treat it like "MoveOut"
if (!dataFlowOut && !alwaysAssigned && variableDeclared && !writtenInside && readOutside)
{
key = new Key(dataFlowIn, /*dataFlowOut*/ true, alwaysAssigned, variableDeclared, readInside, writtenInside, readOutside, writtenOutside);
}
// interesting case in invalid code (bug #19136)
// variable is passed by reference, and another argument is an out variable with the same name
if (dataFlowIn && variableDeclared)
{
key = new Key(/*dataFlowIn:*/ false, dataFlowOut, alwaysAssigned, variableDeclared, readInside, writtenInside, readOutside, writtenOutside);
}
}
if (s_matrix.TryGetValue(key, out variableStyle))
{
return(true);
}
if (bestEffort)
{
// In best effort mode, even though we didn't know precisely what to do, we still
// allow the user to keep going, assuming that this variable is a very basic one.
variableStyle = VariableStyle.InputOnly;
return(true);
}
// Some combination we didn't anticipate. Can't do anything here. Log the issue
// and bail out.
FatalError.ReportWithoutCrash(new Exception($"extract method encountered unknown states: {key.ToString()}"));
return(false);
}