public AP.ExtractMethodResponse ExtractMethod(AP.ExtractMethodRequest input, int version)
{
// tighten up the selection so that we don't expand into any enclosing nodes because we overlap w/ their white space...
var selectionStart = input.startIndex;
while (selectionStart < _code.Length &&
Char.IsWhiteSpace(_code[selectionStart]))
{
selectionStart++;
}
var selectionEnd = input.endIndex;
if (selectionEnd == _code.Length)
{
selectionEnd -= 1;
}
while (selectionEnd >= 0 && Char.IsWhiteSpace(_code[selectionEnd]))
{
selectionEnd -= 1;
}
var walker = new EnclosingNodeWalker(_ast, selectionStart, selectionEnd);
_ast.Walk(walker);
Debug.Assert(walker.Target != null);
if (walker.Target == null)
{
return(new AP.ExtractMethodResponse()
{
cannotExtractMsg = "Invalid target selected"
});
}
bool expanded = false;
// expand the selection if we aren't currently covering a full expression/statement
if (!walker.Target.IsValidSelection)
{
return(new AP.ExtractMethodResponse()
{
cannotExtractMsg = "Invalid expression selected"
});
}
expanded = WasSelectionExpanded(walker.Target, selectionStart, selectionEnd);
// check for things we cannot handle
string failureReason;
if (!IsValidExtraction(walker.Target, out failureReason))
{
return(new AP.ExtractMethodResponse()
{
cannotExtractMsg = failureReason
});
}
// get the variables which are read by the selected statement(s)
var varCollector = new InnerVariableWalker(_ast);
walker.Target.Walk(varCollector);
// Walk the target to understand flow control and definite assignment to further understand
// what we need to flow in. For example if a variable is assigned to both in the un-extracted
// and extracted code but it's definitely assigned in the extracted code then we don't need
// to flow the variable in.
// Run flow checker, first on any nested scopes...
foreach (ScopeStatement scope in varCollector._scopes)
{
FlowChecker.Check(scope);
}
// then on our extracted code
var parent = walker.Target.Parents[walker.Target.Parents.Length - 1];
HashSet <PythonVariable> readBeforeInit;
FlowChecker extractedChecker = null;
if (parent.ScopeVariables != null)
{
extractedChecker = new FlowChecker(parent);
walker.Target.Walk(extractedChecker);
readBeforeInit = extractedChecker.ReadBeforeInitializedVariables;
}
else
{
readBeforeInit = new HashSet <PythonVariable>();
}
// then on code which follows our extracted body
var afterStmts = walker.Target.GetStatementsAfter(_ast);
HashSet <PythonVariable> readByFollowingCodeBeforeInit = null;
var parentNode = walker.Target.Parents[walker.Target.Parents.Length - 1];
var outputVars = new HashSet <PythonVariable>();
if (parentNode.ScopeVariables != null)
{
var checker = new FlowChecker(parentNode);
foreach (var afterStmt in afterStmts)
{
afterStmt.Walk(checker);
}
readByFollowingCodeBeforeInit = checker.ReadBeforeInitializedVariables;
foreach (var variable in varCollector._allWrittenVariables)
{
if (variable != null && variable.Scope is PythonAst)
{
// global variable assigned to in outer scope, and left with
// a valid value (not deleted) from the extracted code. We
// need to pass the value back out and assign to it in the
// global scope.
if (!checker.IsInitialized(variable) &&
extractedChecker.IsAssigned(variable))
{
outputVars.Add(variable);
}
}
}
}
// collect any nested scopes, and see if they read any free variables
var scopeCollector = new ScopeCollector();
foreach (var afterStmt in afterStmts)
{
afterStmt.Walk(scopeCollector);
}
foreach (var scope in scopeCollector._scopes)
{
if (scope.FreeVariables != null)
{
foreach (var freeVar in scope.FreeVariables)
{
if (varCollector._allWrittenVariables.Contains(freeVar))
{
// we've assigned to a variable accessed from an inner
// scope, we need to get the value of the variable back out.
outputVars.Add(freeVar);
}
}
}
}
// discover any variables which are consumed and need to be available as outputs...
var outputCollector = new OuterVariableWalker(_ast, walker.Target, varCollector, readBeforeInit, readByFollowingCodeBeforeInit, outputVars);
_ast.Walk(outputCollector);
if (outputCollector._outputVars.Count > 0 &&
walker.Target.ContainsReturn)
{
return(new AP.ExtractMethodResponse()
{
cannotExtractMsg = "Cannot extract method that assigns to variables and returns"
});
}
var targetScope = walker.Target.Parents[input.scope ?? 0];
var creator = new OutOfProcExtractedMethodCreator(
_ast,
walker.Target.Parents,
outputCollector._inputVars,
outputCollector._outputVars,
walker.Target,
input.indentSize,
!input.convertTabsToSpaces,
input.newLine,
input.name,
input.parameters ?? new string[0],
walker.Target.Parents[input.scope ?? 0]
);
// get the new method body...
var newMethod = creator.GetExtractionResult();
List <AP.ChangeInfo> changes = new List <AP.ChangeInfo>();
changes.Add(
new AP.ChangeInfo()
{
start = walker.Target.StartIncludingIndentation,
length = walker.Target.End - walker.Target.StartIncludingIndentation,
newText = ""
}
);
changes.Add(
new AP.ChangeInfo()
{
start = walker.Target.InsertLocations[targetScope],
newText = newMethod.Method
}
);
changes.Add(
new AP.ChangeInfo()
{
start = walker.Target.StartIncludingIndentation,
newText = newMethod.Call
}
);
List <AP.ScopeInfo> scopes = new List <AP.ScopeInfo>();
for (int i = 0; i < walker.Target.Parents.Length; i++)
{
var scope = walker.Target.Parents[i];
var scopeInfo = new AP.ScopeInfo()
{
name = scope.Name,
id = i,
type = GetScopeType(scope),
variables = GetScopeVariables(scope, outputCollector._inputVars)
};
scopes.Add(scopeInfo);
}
return(new AP.ExtractMethodResponse()
{
changes = changes.ToArray(),
methodBody = newMethod.Method,
variables = outputCollector._inputVars.Select(x => x.Name).ToArray(),
scopes = scopes.ToArray(),
wasExpanded = expanded,
startIndex = walker.Target.StartIncludingIndentation,
endIndex = walker.Target.End,
version = version
});
}
public AP.ExtractMethodResponse ExtractMethod(AP.ExtractMethodRequest input, int version)
{
return(_extractor.ExtractMethod(input, version));
}
