/// <summary>
/// Looks at the enumerator's get_Current method and figures out which of the fields holds the current value.
/// </summary>
void AnalyzeCurrentProperty()
{
MethodDefinition getCurrentMethod = enumeratorType.Methods.FirstOrDefault(
m => m.Name.StartsWith("System.Collections.Generic.IEnumerator", StringComparison.Ordinal)
&& m.Name.EndsWith(".get_Current", StringComparison.Ordinal));
ILBlock method = CreateILAst(getCurrentMethod);
if (method.Body.Count == 1) {
// release builds directly return the current field
ILExpression retExpr;
FieldReference field;
ILExpression ldFromObj;
if (method.Body[0].Match(ILCode.Ret, out retExpr) &&
retExpr.Match(ILCode.Ldfld, out field, out ldFromObj) &&
ldFromObj.MatchThis())
{
currentField = GetFieldDefinition(field);
}
} else if (method.Body.Count == 2) {
ILVariable v, v2;
ILExpression stExpr;
FieldReference field;
ILExpression ldFromObj;
ILExpression retExpr;
if (method.Body[0].Match(ILCode.Stloc, out v, out stExpr) &&
stExpr.Match(ILCode.Ldfld, out field, out ldFromObj) &&
ldFromObj.MatchThis() &&
method.Body[1].Match(ILCode.Ret, out retExpr) &&
retExpr.Match(ILCode.Ldloc, out v2) &&
v == v2)
{
currentField = GetFieldDefinition(field);
}
}
if (currentField == null)
throw new YieldAnalysisFailedException();
}
public void AddFieldDefinition (FieldDefinition field)
{
Fields [field.token.RID - 1] = field;
}
/// <summary>
/// Looks at the enumerator's ctor and figures out which of the fields holds the state.
/// </summary>
void AnalyzeCtor()
{
ILBlock method = CreateILAst(enumeratorCtor);
foreach (ILNode node in method.Body) {
FieldReference field;
ILExpression instExpr;
ILExpression stExpr;
ILVariable arg;
if (node.Match(ILCode.Stfld, out field, out instExpr, out stExpr) &&
instExpr.MatchThis() &&
stExpr.Match(ILCode.Ldloc, out arg) &&
arg.IsParameter && arg.OriginalParameter.Index == 0)
{
stateField = GetFieldDefinition(field);
}
}
if (stateField == null)
throw new YieldAnalysisFailedException();
}
