public virtual SwitchCaseList VisitSwitchCaseList(SwitchCaseList switchCases, SwitchCaseList changes, SwitchCaseList deletions, SwitchCaseList insertions){
if (switchCases == null) return changes;
if (changes != null){
if (deletions == null || insertions == null)
Debug.Assert(false);
else{
}
}else if (deletions != null)
return null;
return switchCases;
}
public virtual Differences VisitSwitchCaseList(SwitchCaseList list1, SwitchCaseList list2,
out SwitchCaseList changes, out SwitchCaseList deletions, out SwitchCaseList insertions){
changes = list1 == null ? null : list1.Clone();
deletions = list1 == null ? null : list1.Clone();
insertions = list1 == null ? new SwitchCaseList() : list1.Clone();
//^ assert insertions != null;
Differences differences = new Differences();
for (int j = 0, n = list2 == null ? 0 : list2.Count; j < n; j++){
//^ assert list2 != null;
SwitchCase nd2 = list2[j];
if (nd2 == null) continue;
insertions.Add(null);
}
TrivialHashtable savedDifferencesMapFor = this.differencesMapFor;
this.differencesMapFor = null;
TrivialHashtable matchedNodes = new TrivialHashtable();
for (int i = 0, k = 0, n = list1 == null ? 0 : list1.Count; i < n; i++){
//^ assert list1 != null && changes != null && deletions != null;
SwitchCase nd1 = list1[i];
if (nd1 == null) continue;
Differences diff;
int j;
SwitchCase nd2 = this.GetClosestMatch(nd1, list1, list2, i, ref k, matchedNodes, out diff, out j);
if (nd2 == null || diff == null){Debug.Assert(nd2 == null && diff == null); continue;}
matchedNodes[nd1.UniqueKey] = nd1;
matchedNodes[nd2.UniqueKey] = nd2;
changes[i] = diff.Changes as SwitchCase;
deletions[i] = diff.Deletions as SwitchCase;
insertions[i] = diff.Insertions as SwitchCase;
insertions[n+j] = nd1; //Records the position of nd2 in list2 in case the change involved a permutation
Debug.Assert(diff.Changes == changes[i] && diff.Deletions == deletions[i] && diff.Insertions == insertions[i]);
differences.NumberOfDifferences += diff.NumberOfDifferences;
differences.NumberOfSimilarities += diff.NumberOfSimilarities;
}
//Find deletions
for (int i = 0, n = list1 == null ? 0 : list1.Count; i < n; i++){
//^ assert list1 != null && changes != null && deletions != null;
SwitchCase nd1 = list1[i];
if (nd1 == null) continue;
if (matchedNodes[nd1.UniqueKey] != null) continue;
changes[i] = null;
deletions[i] = nd1;
insertions[i] = null;
differences.NumberOfDifferences += 1;
}
//Find insertions
for (int j = 0, n = list1 == null ? 0 : list1.Count, m = list2 == null ? 0 : list2.Count; j < m; j++){
//^ assert list2 != null;
SwitchCase nd2 = list2[j];
if (nd2 == null) continue;
if (matchedNodes[nd2.UniqueKey] != null) continue;
insertions[n+j] = nd2; //Records nd2 as an insertion into list1, along with its position in list2
differences.NumberOfDifferences += 1; //REVIEW: put the size of the tree here?
}
if (differences.NumberOfDifferences == 0){
changes = null;
deletions = null;
insertions = null;
}
this.differencesMapFor = savedDifferencesMapFor;
return differences;
}
public virtual SwitchCase GetClosestMatch(SwitchCase/*!*/ nd1, SwitchCaseList/*!*/ list1, SwitchCaseList list2, int list1pos, ref int list2start,
TrivialHashtable/*!*/ matchedNodes, out Differences closestDifferences, out int list2pos) {
closestDifferences = null; list2pos = -1;
if (list2 == null) return null;
if (nd1 == null || list1 == null || matchedNodes == null || list1pos < 0 || list1pos >= list1.Count || list2start < 0 || list2start >= list2.Count) {
Debug.Assert(false); return null;
}
SwitchCase closest = null;
Differences winnerSoFar = null;
for (int j = list2start, m = list2.Count; j < m; j++){
SwitchCase nd2 = list2[j];
if (list2start == j) list2start++;
if (nd2 == null) continue;
if (matchedNodes[nd2.UniqueKey] != null) continue;
Differences diff = this.GetDifferences(nd1, nd2);
if (diff == null){Debug.Assert(false); continue;}
if (diff.Similarity <= 0.5){
//Not a good enough match
if (list2start == j+1) list2start--; //The next call to GetClosestMatch will start looking at list2start, so this node will be considered then
continue; //ignore it for the rest of this call
}
if (winnerSoFar != null && winnerSoFar.Similarity >= diff.Similarity) continue;
winnerSoFar = closestDifferences = diff;
closest = nd2;
list2pos = j;
if (diff.NumberOfDifferences == 0) return closest; //Perfect match, no need to look for other matches
}
if (closest != null){
//^ assert winnerSoFar != null;
//closest is closer to nd1 than any other node in list2, but this is no good if some other node in list1 has a better claim on closest
for (int i = list1pos+1, n = list1.Count; i < n; i++){
SwitchCase nd1alt = list1[i];
if (nd1alt == null) continue;
if (matchedNodes[nd1alt.UniqueKey] != null) continue;
Differences diff = this.GetDifferences(nd1alt, closest);
if (diff == null){Debug.Assert(false); continue;}
if (diff.Similarity <= winnerSoFar.Similarity) continue;
//nd1alt has a better claim on closest. See if it wants closest.
Differences diff2;
int j, k = list2start;
SwitchCase nd2alt = this.GetClosestMatch(nd1alt, list1, list2, i, ref k, matchedNodes, out diff2, out j);
if (nd2alt != closest){
Debug.Assert(nd2alt != null && diff2 != null && diff2.Similarity >= diff.Similarity);
continue; //nd1alt prefers nd2alt to closest, so closest is still available
}
//nd1alt wants closest, take it out of the running
matchedNodes[closest.UniqueKey] = nd1alt;
//Now that closest is out of the running, try again
k = list2start;
SwitchCase newClosest = this.GetClosestMatch(nd1, list1, list2, i, ref k, matchedNodes, out winnerSoFar, out list2pos);
//put closest back in the running so that the next call to this routine will pick it up
matchedNodes[closest.UniqueKey] = closest;
closest = newClosest;
break;
}
}
closestDifferences = winnerSoFar;
return closest;
}
public override Statement VisitSwitch(Switch Switch) {
if (Switch == null) return null;
this.CheckForDuplicateDeclarations(Switch.Scope);
Expression swexpr = this.VisitExpression(Switch.Expression);
if (swexpr == null) return null;
TypeNode swexprType = swexpr.Type;
Reference r = swexprType as Reference;
if (r != null) swexprType = r.ElementType;
if (this.typeSystem.IsNullableType(swexprType)) {
Switch.Nullable = new Local(swexprType);
Switch.NullableExpression = swexpr;
swexprType = this.typeSystem.RemoveNullableWrapper(swexprType);
Switch.Expression = swexpr = this.typeSystem.ExplicitCoercion(Switch.Nullable, swexprType, this.TypeViewer);
}
TypeNode govType = this.GetGoverningType(swexprType);
if (govType == null)
this.HandleError(swexpr, Error.IntegralTypeValueExpected);
else {
if (swexprType != swexpr.Type) swexpr = this.typeSystem.ExplicitCoercion(swexpr, swexprType, this.TypeViewer);
Switch.Expression = swexpr = this.typeSystem.ImplicitCoercion(swexpr, govType, this.TypeViewer);
}
TypeNode savedGoverningType = this.currentSwitchGoverningType;
this.currentSwitchGoverningType = govType;
SwitchCaseList cases = Switch.Cases;
if (swexpr == null || cases == null) return null;
Literal swlit = swexpr as Literal;
int n = cases.Count;
SwitchCaseList savedCases = this.currentSwitchCases;
this.currentSwitchCases = cases;
Hashtable alreadySeenLabelValues = new Hashtable();
for (int i = 0; i < n; i++) {
SwitchCase scase = cases[i];
if (scase == null) continue;
Literal lit = scase.Label as Literal;
if (lit == null && scase.Label != null) {
MemberBinding mb = scase.Label as MemberBinding;
if (mb != null && mb.BoundMember is Field && ((Field)mb.BoundMember).IsLiteral)
lit = ((Field)mb.BoundMember).DefaultValue;
if (lit == null) {
this.HandleError(scase.Label, Error.ConstantExpected);
cases[i] = null; continue;
}
}
if (lit != null && govType != null) {
if (Switch.Nullable == null || !Literal.IsNullLiteral(lit))
lit = this.typeSystem.ImplicitLiteralCoercion(lit, lit.Type, govType, this.TypeViewer);
if (lit != null && lit.Value != null) {
Node prev = (Node)alreadySeenLabelValues[lit.Value];
if (prev != null) {
this.HandleError(scase.Label, Error.DuplicateCaseLabel, "case "+scase.Label.SourceContext.SourceText+":");
this.HandleError(prev, Error.RelatedErrorLocation);
}
alreadySeenLabelValues[lit.Value] = scase.Label;
if (swlit != null && swlit.Value != null && lit.Value != null && !swlit.Value.Equals(lit.Value)) {
this.HandleError(scase, Error.UnreachableCode);
if (scase.Body != null && scase.Body.Statements != null && scase.Body.Statements.Count > 0 &&
scase.Body.Statements[scase.Body.Statements.Count-1] != null &&
scase.Body.Statements[scase.Body.Statements.Count-1].NodeType == NodeType.SwitchCaseBottom)
scase.Body.Statements[scase.Body.Statements.Count-1] = null;
scase.IsErroneous = true;
}
}
scase.Label = lit;
}
}
this.switchCaseCount++;
for (int i = 0; i < n; i++) {
SwitchCase scase = cases[i];
if (scase == null) continue;
scase.Body = this.VisitBlock(scase.Body);
}
this.switchCaseCount--;
this.currentSwitchCases = savedCases;
this.currentSwitchGoverningType = savedGoverningType;
return Switch;
}
public virtual SwitchCaseList VisitSwitchCaseList(SwitchCaseList switchCases){
if (switchCases == null) return null;
for (int i = 0, n = switchCases.Count; i < n; i++)
switchCases[i] = this.Visit(switchCases[i]) as SwitchCase;
return switchCases;
}
public override SwitchCaseList VisitSwitchCaseList(SwitchCaseList switchCases)
{
throw new ApplicationException("unimplemented");
}
public virtual void VisitSwitchCaseList(SwitchCaseList switchCases)
{
if (switchCases == null) return;
for (int i = 0, n = switchCases.Count; i < n; i++)
this.Visit(switchCases[i]);
}
public override SwitchCaseList VisitSwitchCaseList(SwitchCaseList switchCases)
{
if (switchCases == null) return null;
return base.VisitSwitchCaseList(switchCases.Clone());
}
public virtual SwitchCaseList VisitSwitchCaseList(SwitchCaseList switchCases1, SwitchCaseList switchCases2)
{
if (switchCases1 == null) return null;
for (int i = 0, n = switchCases1.Count, m = switchCases2 == null ? 0 : switchCases2.Count; i < n; i++)
{
//^ assert switchCases2 != null;
if (i >= m)
switchCases1[i] = this.VisitSwitchCase(switchCases1[i], null);
else
switchCases1[i] = this.VisitSwitchCase(switchCases1[i], switchCases2[i]);
}
return switchCases1;
}
public Switch(Expression expression, SwitchCaseList cases)
: base(NodeType.Switch)
{
this.Cases = cases;
this.Expression = expression;
}
public override SwitchCaseList VisitSwitchCaseList(SwitchCaseList switchCases)
{
throw new ApplicationException("unimplemented");
}
public EventingVisitor(Action<SwitchCaseList> visitSwitchCaseList) { VisitedSwitchCaseList += visitSwitchCaseList; } public event Action<SwitchCaseList> VisitedSwitchCaseList; public override SwitchCaseList VisitSwitchCaseList(SwitchCaseList switchCases) { if (VisitedSwitchCaseList != null) VisitedSwitchCaseList(switchCases); return base.VisitSwitchCaseList(switchCases); }