protected SeparatedElement(SyntaxElement element, SyntaxToken separator = null)
: base(null)
{
this.Element = Attach(element);
this.Separator = Attach(separator, optional: true);
this.Init();
}
protected static void GatherDiagnostics(
SyntaxElement root,
List <Diagnostic> diagnostics,
DiagnosticsInclude include,
CancellationToken cancellationToken = default(CancellationToken))
{
cancellationToken.ThrowIfCancellationRequested();
bool includeSyntax = (include & DiagnosticsInclude.Syntactic) != 0;
bool includeSemantic = (include & DiagnosticsInclude.Semantic) != 0;
bool includeExpansion = (include & DiagnosticsInclude.Expansion) != 0;
var fnDescend = (include == DiagnosticsInclude.Syntactic)
? (Func <SyntaxElement, bool>)((SyntaxElement e) => e.ContainsSyntaxDiagnostics)
: null;
SyntaxElement.WalkElements(root,
fnBefore: element =>
{
if (element.HasSyntaxDiagnostics && includeSyntax)
{
// each syntax diagnostic is located at the element that carries it.
diagnostics.AddRange(element.SyntaxDiagnostics.Select(d => d.HasLocation ? d : SetLocation(d, element)));
}
if (includeSemantic && element is SyntaxNode node && node.SemanticDiagnostics.Count > 0)
{
diagnostics.AddRange(node.SemanticDiagnostics);
}
},
/// <summary>
/// Gets the descendants of the specified element that match the specified type and predicate.
/// </summary>
private static List <TElement> GetDescendants <TElement>(SyntaxElement element, Func <TElement, bool> predicate, List <TElement> list)
where TElement : SyntaxElement
{
for (int i = 0; i < element.ChildCount; i++)
{
var child = element.GetChild(i);
if (child != null)
{
if (child is TElement ce && (predicate == null || predicate(ce)))
{
if (list == null)
{
list = new List <TElement>();
}
list.Add(ce);
}
if (child is SyntaxNode cn)
{
list = GetDescendants(child, predicate, list);
}
}
}
return(list);
}
internal void InitializeTriviaStarts()
{
SyntaxElement.WalkElements(
this.Root,
fnBefore: element =>
{
System.Diagnostics.Debug.Assert(element.Parent == null || element.Parent._triviaStart >= 0);
element._triviaStart = (element.Parent?._triviaStart ?? 0) + element.OffsetInParent;
});
}
/// <summary>
/// Gets the index of the child node, or -1 if the node is not a child.
/// </summary>
public int GetChildIndex(SyntaxElement child)
{
for (int i = 0, n = this.ChildCount; i < n; i++)
{
if (this.GetChild(i) == child)
{
return(i);
}
}
return(-1);
}
/// <summary>
/// Walks this element and its descendants in lexical order, invoking the actions for each <see cref="SyntaxElement"/> including the root element.
/// </summary>
/// <param name="root">The root element of the walk. The walk includes this element and any descendant elements.</param>
/// <param name="fnBefore">An optional function that is invoked for each element before any child elements are visited.</param>
/// <param name="fnAfter">An optional function that is invoked for each element after any child elements have been visited.</param>
/// <param name="fnDescend">An optional function that determines whether the children of an element are visited.</param>
public static void WalkElements(
SyntaxElement root,
Action <SyntaxElement> fnBefore = null,
Action <SyntaxElement> fnAfter = null,
Func <SyntaxElement, bool> fnDescend = null)
{
if (root == null)
{
throw new ArgumentNullException(nameof(root));
}
var node = root;
var childIndex = 0;
// the root before walking children
fnBefore?.Invoke(root);
while (node != null)
{
if (childIndex < node.ChildCount && childIndex >= 0 && (fnDescend == null || fnDescend(node)))
{
// walk down
var child = node.GetChild(childIndex);
if (child != null)
{
node = child;
childIndex = 0;
// before walking children
fnBefore?.Invoke(node);
}
else
{
childIndex++;
}
}
else
{
// after walking children
fnAfter?.Invoke(node);
// stop if we are done with root node
if (node == root)
{
break;
}
// walk up
childIndex = node.IndexInParent + 1;
node = node.Parent;
}
}
}
/// <summary>
/// Gets the descendants of the specified element that match the specified type and predicate.
/// </summary>
private static IReadOnlyList <TElement> GetDescendants <TElement>(
SyntaxElement element,
Func <TElement, bool> predicate,
bool includeSelf)
where TElement : SyntaxElement
{
List <TElement> list = null;
if (includeSelf && element is TElement telem && (predicate == null || predicate(telem)))
{
list = list ?? new List <TElement>();
list.Add(telem);
}
var root = element;
var childIndex = 0;
while (element != null)
{
if (childIndex < element.ChildCount && childIndex >= 0)
{
// walk down
var child = element.GetChild(childIndex);
if (child != null)
{
element = child;
childIndex = 0;
if (element is TElement telem2 && (predicate == null || predicate(telem2)))
{
list = list ?? new List <TElement>();
list.Add(telem2);
}
}
else
{
childIndex++;
}
}
else if (element == root)
{
break;
}
else
{
// walk up
childIndex = element.IndexInParent + 1;
element = element.Parent;
}
}
return(list != null?list.ToReadOnly() : EmptyReadOnlyList <TElement> .Instance);
}
/// <summary>
/// Gets the first ancestor of this element that matches the specified type and predicate.
/// </summary>
public TElement GetFirstAncestor <TElement>(Func <TElement, bool> predicate = null)
where TElement : SyntaxElement
{
for (SyntaxElement elem = this.Parent; elem != null; elem = elem.Parent)
{
if (elem is TElement e && (predicate == null || predicate(e)))
{
return(e);
}
}
return(default(TElement));
}
/// <summary>
/// Returns true if this element is the ancestor of the specified element.
/// </summary>
public bool IsAncestorOf(SyntaxElement element)
{
while (element != null)
{
if (element.Parent == this)
{
return(true);
}
element = element.Parent;
}
return(false);
}
protected static void GatherDiagnostics(
SyntaxElement element,
List <Diagnostic> diagnostics,
DiagnosticsInclude include,
CancellationToken cancellationToken = default(CancellationToken))
{
cancellationToken.ThrowIfCancellationRequested();
bool includeSyntax = (include & DiagnosticsInclude.Syntactic) != 0;
bool includeSemantic = (include & DiagnosticsInclude.Semantic) != 0;
bool includeExpansion = (include & DiagnosticsInclude.Expansion) != 0;
if (element.HasSyntaxDiagnostics && includeSyntax)
{
// each syntax diagnostic is located at the element that carries it.
diagnostics.AddRange(element.SyntaxDiagnostics.Select(d => d.HasLocation ? d : SetLocation(d, element)));
}
if (includeSemantic && element is SyntaxNode node && node.SemanticDiagnostics.Count > 0)
{
diagnostics.AddRange(node.SemanticDiagnostics);
}
if (includeSemantic || (includeSyntax && element.ContainsSyntaxDiagnostics))
{
for (int i = 0, n = element.ChildCount; i < n; i++)
{
var child = element.GetChild(i);
if (child != null)
{
GatherDiagnostics(child, diagnostics, include, cancellationToken);
}
}
}
if (includeExpansion && element is Expression expr && expr.GetExpansion() is SyntaxNode expansion)
{
var originalCount = diagnostics.Count;
GatherDiagnostics(expansion, diagnostics, include, cancellationToken);
if (diagnostics.Count > originalCount)
{
var name = expr.ReferencedSymbol?.Name ?? "<unknown>";
var location = expr is FunctionCallExpression fc ? fc.Name : expr;
var errors = diagnostics[originalCount].Message;
var dx = DiagnosticFacts.GetErrorInExpansion(name, errors).WithLocation(location);
diagnostics.SetCount(originalCount);
diagnostics.Add(dx);
}
}
}
private static TElement GetFirstDescendant <TElement>(SyntaxElement element, Func <TElement, bool> predicate, bool includeSelf)
where TElement : SyntaxElement
{
if (includeSelf && element is TElement telem && (predicate == null || predicate(telem)))
{
return(telem);
}
var root = element;
var childIndex = 0;
while (element != null)
{
if (childIndex < element.ChildCount && childIndex >= 0)
{
// walk down
var child = element.GetChild(childIndex);
if (child != null)
{
element = child;
childIndex = 0;
if (element is TElement telem2 && (predicate == null || predicate(telem2)))
{
return(telem2);
}
}
else
{
childIndex++;
}
}
else if (element == root)
{
break;
}
else
{
// walk up
childIndex = element.IndexInParent + 1;
element = element.Parent;
}
}
return(null);
}
/// <summary>
/// Walks the entire syntax tree and evaluates the maximum depth of all the nodes.
/// </summary>
private static int ComputeMaxDepth(SyntaxNode root)
{
var maxDepth = 0;
var depth = 0;
SyntaxElement.WalkNodes(
root,
fnBefore: e =>
{
depth++;
if (depth > maxDepth)
{
maxDepth = depth;
}
},
fnAfter: e => depth--);
return(maxDepth);
}
/// <summary>
/// Gets the all ancestors of this element (including itself) that match the specified type and predicate.
/// </summary>
public IReadOnlyList <TElement> GetAncestors <TElement>(Func <TElement, bool> predicate = null)
where TElement : SyntaxElement
{
List <TElement> list = null;
for (SyntaxElement elem = this.Parent; elem != null; elem = elem.Parent)
{
if (elem is TElement e && (predicate == null || predicate(e)))
{
if (list == null)
{
list = new List <TElement>();
}
list.Add(e);
}
}
return(list != null?list.ToReadOnly() : EmptyReadOnlyList <TElement> .Instance);
}
private static Diagnostic SetLocation(Diagnostic d, SyntaxElement location)
{
if (location.Width == 0)
{
if (location is SyntaxToken token)
{
// move location to next token if it is
// lest than two spaces away and not separated by line breaks
var next = token.GetNextToken();
if (next != null &&
(next.TextStart - token.End) < 2 &&
!TextFacts.HasLineBreaks(next.Trivia))
{
location = next;
}
}
}
return(d.WithLocation(location));
}
/// <summary>
/// Gets the next <see cref="SyntaxToken"/> in lexical order.
/// </summary>
public SyntaxToken GetNextToken(bool includeZeroWidthTokens = false)
{
for (SyntaxElement node = this; node != null; node = node.Parent)
{
var sibling = node.GetNextSibling(includeZeroWidthTokens);
if (sibling != null)
{
if (sibling.IsToken)
{
return((SyntaxToken)sibling);
}
var first = sibling.GetFirstToken(includeZeroWidthTokens);
if (first != null)
{
return(first);
}
}
}
return(null);
}
/// <summary>
/// Gets the previous <see cref="SyntaxToken"/> in lexical orer.
/// </summary>
public SyntaxToken GetPreviousToken(bool includeZeroWidthTokens = false)
{
for (SyntaxElement node = this; node != null; node = node.Parent)
{
var sibling = node.GetPreviousSibling();
if (sibling != null)
{
if (sibling.IsToken)
{
return((SyntaxToken)sibling);
}
var last = sibling.GetLastToken(includeZeroWidthTokens);
if (last != null)
{
return(last);
}
}
}
return(null);
}
protected static SyntaxToken GetPreviousToken(SyntaxElement root, SyntaxToken token, bool includeZeroWidthTokens)
{
var node = token != null ? token.Parent : root;
var childIndex = token != null ? token.IndexInParent - 1 : root.ChildCount - 1;
while (node != null)
{
if (childIndex < node.ChildCount && childIndex >= 0)
{
var child = node.GetChild(childIndex);
if (child != null)
{
node = child;
childIndex = node.ChildCount - 1;
if (node is SyntaxToken t && (includeZeroWidthTokens || t.FullWidth > 0))
{
return(t);
}
}
else
{
childIndex--;
}
}
else if (node == root)
{
return(null);
}
else
{
childIndex = node.IndexInParent - 1;
node = node.Parent;
}
}
return(null);
}
