public bool VertifyRule(TRule rule, out IList <Exception> exceptions)
{
string cacheKey = GetCacheKey(rule);
if (_cache.ContainsKey(cacheKey))
{
exceptions = null;
return(true);
}
var visitResult = DataPrivilegeVisitor.Visit(rule.ConditionExpression);
exceptions = visitResult.Exceptions;
if (visitResult.Success)
{
ReplacementVisitor visitor = new ReplacementVisitor(Expression.Constant(this), visitResult.PredicateExpression.Parameters[0], _parameterExpression);
var newExpression = visitor.Visit(visitResult.PredicateExpression);
if (newExpression.CanReduce)
{
newExpression = newExpression.Reduce();
}
DataPrivilegeInfo <TEntity> result = new DataPrivilegeInfo <TEntity>(newExpression as Expression <Func <TEntity, bool> >, visitResult.CustomFields);
_cache.TryAdd(cacheKey, result);
}
return(visitResult.Success);
}
private Expression GetExpressionBodyReferencingValue(LambdaExpression expression, Expression newParameterExpression)
{
var parameterToBeReplaced = expression.Parameters[0];
var visitor = new ReplacementVisitor(parameterToBeReplaced, newParameterExpression);
return(visitor.Visit(expression.Body));
}
static Expression <Func <bool> > Substitute <TException>(Expression <Func <TException, bool> > expression, TException exception)
{
var parameter = expression.Parameters[0];
var constant = Expression.Constant(exception, typeof(TException));
var visitor = new ReplacementVisitor(parameter, constant);
var newBody = visitor.Visit(expression.Body);
return(Expression.Lambda <Func <bool> >(newBody));
}
private Expression <TLambda> Curry <TLambda>(
LambdaExpression searchExpression,
int replacedParameterIndex,
object replacement)
{
var parameter = searchExpression.Parameters[replacedParameterIndex];
var constant = Expression.Constant(replacement, parameter.Type);
var visitor = new ReplacementVisitor(parameter, constant);
var newBody = visitor.Visit(searchExpression.Body);
var lambda = Expression.Lambda <TLambda>(newBody, searchExpression.Parameters.Except(new[] { parameter }));
return(lambda);
}
public static Expression Replace(
LambdaExpression source,
Expression toFind,
Expression toReplace)
{
var visitor = new ReplacementVisitor
{
SourceParameters = source.Parameters,
ToFind = toFind,
ToReplace = toReplace,
};
return(visitor.Visit(source.Body));
}
public static Expression Transform(
LambdaExpression source,
Expression find,
Expression replace)
{
var visitor = new ReplacementVisitor
{
Parameters = source.Parameters,
Find = find,
Replace = replace,
};
return(visitor.Visit(source.Body));
}
private DataPrivilegeInfo <TEntity> GetDataPrevilegeInfoByRule(TRule rule)
{
string cacheKey = GetCacheKey(rule);
return(_cache.GetOrAdd(cacheKey, _ =>
{
var visitResult = DataPrivilegeVisitor.Visit(rule.ConditionExpression);
if (!visitResult.Success)
{
throw new AggregateException(visitResult.Exceptions);
}
ReplacementVisitor visitor = new ReplacementVisitor(Expression.Constant(this), visitResult.PredicateExpression.Parameters[0], _parameterExpression);
var newExpression = visitor.Visit(visitResult.PredicateExpression);
DataPrivilegeInfo <TEntity> result = new DataPrivilegeInfo <TEntity>(newExpression as Expression <Func <TEntity, bool> >, visitResult.CustomFields);
return result;
}));
}