/// <summary>
/// Implement the skipping. We have a main limitation: we currently know only how to implement integer skipping.
/// We implement with "if" statements to support composability, even if it means running longer in the end...
/// We actually return nothing when goes - we aren't really a final result the way "Count" is.
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <returns></returns>
public void ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode codeEnv, ICodeContext codeContext, CompositionContainer container)
{
///
/// Quick checks to make sure
///
if (codeEnv == null)
throw new ArgumentNullException("codeEnv cannot be null");
var take = resultOperator as TakeResultOperator;
var skip = resultOperator as SkipResultOperator;
if (take == null && skip == null)
{
throw new ArgumentNullException("resultOperator must not be null and must represent either a take or a skip operation!");
}
if (take != null && take.Count.Type != typeof(int))
throw new ArgumentException("Take operator count must be an integer!");
if (skip != null && skip.Count.Type != typeof(int))
throw new ArgumentException("Skip operator count must be an integer!");
// If this is a "global" take, then we need to declare the variable a bit specially.
// Global: we have a limit on the number of objects that goes across events. We test this by seeing if this
// is a sub-query that is registered (or not).
var isGlobalTake = codeContext.IsInTopLevelQueryModel(queryModel);
// Now, we create a count variable and that is how we will tell if we are still skipping or
// taking. It must be declared in the current block, before our current code! :-)
var counter = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int), otherDependencies: codeContext.LoopIndexVariable.Return<IDeclaredParameter>());
if (isGlobalTake)
{
counter.DeclareAsStatic = true;
codeEnv.Add(counter);
} else
{
codeEnv.AddOutsideLoop(counter);
}
var comparison = StatementIfOnCount.ComparisonOperator.LessThanEqual;
IValue limit = null;
if (skip != null)
{
comparison = StatementIfOnCount.ComparisonOperator.GreaterThan;
limit = ExpressionToCPP.GetExpression(skip.Count, codeEnv, codeContext, container);
}
else
{
limit = ExpressionToCPP.GetExpression(take.Count, codeEnv, codeContext, container);
}
codeEnv.Add(new StatementIfOnCount(counter, limit, comparison));
///
/// We are particularly fortunate here. We don't have to update the Loop variable - whatever it is, is
/// still the right one! Normally we'd have to futz with the LoopVariable in code context because we
/// were iterating over something new. :-) Easy!
///
}
/// <summary>
/// Take the incoming stream of items, and send them along! :-)
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
public void ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
//
// Some basic checks on the input.
//
if (cc == null)
{
throw new ArgumentNullException("cc");
}
if (gc == null)
{
throw new ArgumentNullException("gc");
}
if (cc.LoopVariable == null)
{
throw new ArgumentNullException("No defined loop variable!");
}
//
// Get the indexer that is being used to access things. We will just push that onto a temp vector of int's. That will be
// a list of the items that we want to come back and look at. That said, once done we need to pop-up one level in our
// depth.
//
var arrayRecord = DeclarableParameter.CreateDeclarableParameterArrayExpression(typeof(int));
gc.AddOutsideLoop(arrayRecord);
var recordIndexStatement = new Statements.StatementRecordIndicies(ExpressionToCPP.GetExpression(cc.LoopIndexVariable.AsExpression(), gc, cc, container), arrayRecord);
gc.Add(recordIndexStatement);
gc.Pop();
//
// Now, we go down one loop and run over the pairs with a special loop.
//
var index1 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var index2 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var indexIterator = new Statements.StatementPairLoop(arrayRecord, index1, index2);
gc.Add(indexIterator);
//
// Finally, build the resulting loop variable. For now it is just a tuple, which is basically the formed expression we started with,
// but with the other index properties. Other bits will have to do the translation for us. :-)
//
var item1 = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index1);
var item2 = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index2);
var tupleType = typeof(Tuple <,>).MakeGenericType(cc.LoopVariable.Type, cc.LoopVariable.Type);
var newTuple = Expression.New(tupleType.GetConstructor(new Type[] { cc.LoopVariable.Type, cc.LoopVariable.Type }), item1, item2);
cc.SetLoopVariable(newTuple, null);
}
/// <summary>
/// Process the grouping operator. We have to sort through the items, group them, and then
/// create an object we can be translated later to access the items or the Key. We need to return
/// an IEnumerable<IGrouping<TKey, TElement>>... As a result, this is one of those operators that has
/// a fair amount of implementation in other parts of the re-linq structure.
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="gc"></param>
/// <param name="cc"></param>
/// <param name="container"></param>
/// <returns></returns>
/// <remarks>
/// re-linq blog post that shows the format of the query we are dealing with: https://www.re-motion.org/blogs/mix/2009/09/01/re-linq-how-to-support-ldquogroup-intordquo-with-aggregates
/// Not as useful:
/// Code for the result operator (including in-memory execution): https://svn.re-motion.org/svn/Remotion/trunk/Relinq/Core/Clauses/ResultOperators/GroupResultOperator.cs
/// Unit tests for the result operator: https://www.re-motion.org/fisheye/browse/~raw,r=17871/Remotion/trunk/Remotion/Data/Linq.UnitTests/Linq/SqlBackend/SqlPreparation/ResultOperatorHandlers/GroupResultOperatorHandlerTest.cs
/// </remarks>
System.Linq.Expressions.Expression IQVScalarResultOperator.ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
//
// Basic checks
//
var groupOp = resultOperator as GroupResultOperator;
if (groupOp == null)
{
throw new ArgumentNullException("resultOperator");
}
if (!groupOp.KeySelector.Type.IsNumberType())
{
throw new InvalidOperationException(string.Format("Don't know how to group by type '{0}'.", groupOp.KeySelector.Type.Name));
}
//
// First, record all the indicies and the values. This is what we are going to be grouping.
//
var mapRecord = DeclarableParameter.CreateDeclarableParameterMapExpression(groupOp.KeySelector.Type, typeof(int).MakeArrayType());
gc.AddOutsideLoop(mapRecord);
var savePairValues = new StatementRecordPairValues(mapRecord,
ExpressionToCPP.GetExpression(groupOp.KeySelector, gc, cc, container),
ExpressionToCPP.GetExpression(cc.LoopIndexVariable.AsExpression(), gc, cc, container));
gc.Add(savePairValues);
gc.Pop();
//
// Now create the object that will be handed back for later parsing. This should contain the info that is needed to do the
// actual looping over the groups when it is requested.
//
var t_return = typeof(GroupByTypeTagEnum <int, int>).GetGenericTypeDefinition().MakeGenericType(new Type[] { groupOp.KeySelector.Type, groupOp.ElementSelector.Type });
var ctor = t_return.GetConstructor(new Type[] { });
var o = ctor.Invoke(new object[] { }) as BaseGroupInfo;
o.MapRecord = mapRecord;
o.TargetExpression = groupOp.ElementSelector;
o.TargetExpressionLoopVariable = cc.LoopIndexVariable;
return(Expression.Constant(o, t_return));
}
/// <summary>
/// Take the incoming stream of items, and send them along! :-)
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
public void ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
//
// Some basic checks on the input.
//
if (cc == null)
throw new ArgumentNullException("cc");
if (gc == null)
throw new ArgumentNullException("gc");
if (cc.LoopVariable == null)
throw new ArgumentNullException("No defined loop variable!");
//
// Get the indexer that is being used to access things. We will just push that onto a temp vector of int's. That will be
// a list of the items that we want to come back and look at. That said, once done we need to pop-up one level in our
// depth.
//
var arrayRecord = DeclarableParameter.CreateDeclarableParameterArrayExpression(typeof(int));
gc.AddOutsideLoop(arrayRecord);
var recordIndexStatement = new Statements.StatementRecordIndicies(ExpressionToCPP.GetExpression(cc.LoopIndexVariable.AsExpression(), gc, cc, container), arrayRecord);
gc.Add(recordIndexStatement);
gc.Pop();
//
// Now, we go down one loop and run over the pairs with a special loop.
//
var index1 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var index2 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var indexIterator = new Statements.StatementPairLoop(arrayRecord, index1, index2);
gc.Add(indexIterator);
//
// Finally, build the resulting loop variable. For now it is just a tuple, which is basically the formed expression we started with,
// but with the other index properties. Other bits will have to do the translation for us. :-)
//
var item1 = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index1);
var item2 = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index2);
var tupleType = typeof(Tuple<,>).MakeGenericType(cc.LoopVariable.Type, cc.LoopVariable.Type);
var newTuple = Expression.New(tupleType.GetConstructor(new Type[] { cc.LoopVariable.Type, cc.LoopVariable.Type }), item1, item2);
cc.SetLoopVariable(newTuple, null);
}
public Expression ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel,
IGeneratedQueryCode gc, ICodeContext cc,
CompositionContainer container)
{
if (resultOperator == null)
{
throw new ArgumentNullException("resultOperator");
}
if (cc == null)
{
throw new ArgumentNullException("CodeContext can't be null");
}
// Determine the type of the result operator we are processing and
// anything we need to know about it.
Type sumType;
sumType = cc.LoopVariable.Type;
bool doAverage = false;
if (resultOperator is SumResultOperator)
{
doAverage = false;
}
else
{
doAverage = true;
}
// We only know how to sum basic types
if (!sumType.IsNumberType())
{
throw new InvalidOperationException(string.Format("Do not know how to generate C++ to sum type {0}.", sumType.Name));
}
var accumulator = DeclarableParameter.CreateDeclarableParameterExpression(sumType);
accumulator.SetInitialValue("0");
// Sum and average are a alike in that we are going to add everything we see up.
var add = Expression.Add(accumulator, cc.LoopVariable);
var addResolved = ExpressionToCPP.GetExpression(add, gc, cc, container);
gc.Add(new StatementAggregate(accumulator, addResolved));
// If this is a sum no further work needs to happen.
if (!doAverage)
{
return(accumulator);
}
// If this is a average then we need to add a simple count.
var counter = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
counter.SetInitialValue("0");
var incbyone = Expression.Add(counter, Expression.Constant(1));
gc.Add(new StatementAggregate(counter, ExpressionToCPP.GetExpression(incbyone, gc, cc, container)));
// Next, we have to delcare the counter and the accumulator. These are now both temprorary variables.
if (cc.LoopIndexVariable == null)
{
throw new AverageNotAllowedAtTopLevelException("Attempt to use Average at top level, accross events. Not currently implemented.");
}
gc.AddOutsideLoop(counter);
gc.AddOutsideLoop(accumulator);
// It is an error to average a sequence with no elements. So we need to throw a C++ exception. We need to pop up out of the loop in order
// to do this.
// http://msdn.microsoft.com/en-us/library/bb354760.aspx (for specs on Average on this).
var testForSomething = Expression.Equal(counter, Expression.Constant(0));
gc.AddAtResultScope(new StatementThrowIfTrue(ExpressionToCPP.GetExpression(testForSomething, gc, cc, container), "Can't take an average of a null sequence"));
var returnType = DetermineAverageReturnType(sumType);
var faccumulator = Expression.Convert(accumulator, returnType);
var fcount = Expression.Convert(counter, returnType);
var divide = Expression.Divide(faccumulator, fcount);
// We are done with this calculation, so pop up and out.
gc.Pop();
return(divide);
}
/// <summary>
/// Implement the skipping. We have a main limitation: we currently know only how to implement integer skipping.
/// We implement with "if" statements to support composability, even if it means running longer in the end...
/// We actually return nothing when goes - we aren't really a final result the way "Count" is.
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <returns></returns>
public void ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode codeEnv, ICodeContext codeContext, CompositionContainer container)
{
///
/// Quick checks to make sure
///
if (codeEnv == null)
{
throw new ArgumentNullException("codeEnv cannot be null");
}
var take = resultOperator as TakeResultOperator;
var skip = resultOperator as SkipResultOperator;
if (take == null && skip == null)
{
throw new ArgumentNullException("resultOperator must not be null and must represent either a take or a skip operation!");
}
if (take != null && take.Count.Type != typeof(int))
{
throw new ArgumentException("Take operator count must be an integer!");
}
if (skip != null && skip.Count.Type != typeof(int))
{
throw new ArgumentException("Skip operator count must be an integer!");
}
// If this is a "global" take, then we need to declare the variable a bit specially.
// Global: we have a limit on the number of objects that goes across events. We test this by seeing if this
// is a sub-query that is registered (or not).
var isGlobalTake = codeContext.IsInTopLevelQueryModel(queryModel);
// Now, we create a count variable and that is how we will tell if we are still skipping or
// taking. It must be declared in the current block, before our current code! :-)
var counter = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int), otherDependencies: codeContext.LoopIndexVariable.Return <IDeclaredParameter>());
if (isGlobalTake)
{
counter.DeclareAsStatic = true;
codeEnv.Add(counter);
}
else
{
codeEnv.AddOutsideLoop(counter);
}
var comparison = StatementIfOnCount.ComparisonOperator.LessThanEqual;
IValue limit = null;
if (skip != null)
{
comparison = StatementIfOnCount.ComparisonOperator.GreaterThan;
limit = ExpressionToCPP.GetExpression(skip.Count, codeEnv, codeContext, container);
}
else
{
limit = ExpressionToCPP.GetExpression(take.Count, codeEnv, codeContext, container);
}
codeEnv.Add(new StatementIfOnCount(counter, limit, comparison));
///
/// We are particularly fortunate here. We don't have to update the Loop variable - whatever it is, is
/// still the right one! Normally we'd have to futz with the LoopVariable in code context because we
/// were iterating over something new. :-) Easy!
///
}
/// <summary>
/// Code up the min/max result operators. We run the loop out, and then
/// we return the result whatever it is. We only work when the type is
/// something simple we can deal with!
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
/// <returns></returns>
public Expression ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
///
/// Some argument checking
///
if (cc == null)
throw new ArgumentNullException("cc");
if (gc == null)
throw new ArgumentNullException("gc");
if (gc.Depth == 1)
throw new ArgumentException("The Max/Min operators can't be used as result operators for a query - they can only be used in a sub-query");
///
/// Is it min or max?
///
var minOperator = resultOperator as MinResultOperator;
var maxOperator = resultOperator as MaxResultOperator;
if (minOperator == null && maxOperator == null)
throw new InvalidOperationException("Should always have min or max operator!");
bool doMax = maxOperator != null;
bool returnDefaultValue = false;
if (doMax)
returnDefaultValue = maxOperator.ReturnDefaultWhenEmpty;
else
returnDefaultValue = minOperator.ReturnDefaultWhenEmpty;
///
/// Next, look at the type of the current result that is running.
///
var valueExpr = queryModel.SelectClause.Selector;
if (!TimeCanBeCompared(valueExpr.Type))
throw new ArgumentException(string.Format("I don't know how to fix the min or max of a sequence of '{0}'s", cc.LoopVariable.Type.Name));
///
/// Now, declare two variables, one bool which gets set when we get the first value,
/// and the other to hold the min/max value! Note that we initalize the variable to
/// the proper type. We don't declare minmax holder - as it may end up be used
/// externally.
///
var vIsFilled = DeclarableParameter.CreateDeclarableParameterExpression(typeof(bool));
vIsFilled.InitialValue = new ValSimple("false", typeof(bool), null);
var vMaxMin = DeclarableParameter.CreateDeclarableParameterExpression(valueExpr.Type);
vMaxMin.InitialValue = new ValSimple("0", typeof(int), null);
gc.AddOutsideLoop(vIsFilled);
///
/// The expression we want to mimize or maximize
///
var exprToMinOrMaximize = ExpressionToCPP.GetExpression(valueExpr, gc, cc, container);
///
/// Now, we just have to put the x-checks in there.
///
var ifStatement = new Statements.StatementMinMaxTest(vIsFilled, vMaxMin, exprToMinOrMaximize, doMax);
gc.Add(ifStatement);
return vMaxMin;
}
/// <summary>
/// Sort the current stream of the query. To do this we run through all the results, sort them,
/// and then start a new loop.
/// </summary>
/// <param name="ordering"></param>
/// <param name="queryModel"></param>
/// <param name="orderByClause"></param>
/// <param name="index"></param>
public override void VisitOrdering(Ordering ordering, QueryModel queryModel, OrderByClause orderByClause, int index)
{
//
// Only number types can be sorted.
//
if (!ordering.Expression.Type.IsNumberType())
{
throw new InvalidOperationException(string.Format("Don't know how to sort query by type '{0}'.", ordering.Expression.Type.Name));
}
//
// First, record all the indicies and the values. This is what we are going to be sorting.
//
var mapRecord = DeclarableParameter.CreateDeclarableParameterMapExpression(ordering.Expression.Type, _codeContext.LoopIndexVariable.Type.MakeArrayType());
_codeEnv.AddOutsideLoop(mapRecord);
var savePairValues = new StatementRecordPairValues(mapRecord,
ExpressionToCPP.GetExpression(ordering.Expression, _codeEnv, _codeContext, MEFContainer),
ExpressionToCPP.GetExpression(_codeContext.LoopIndexVariable.AsExpression(), _codeEnv, _codeContext, MEFContainer));
_codeEnv.Add(savePairValues);
var otherSavers = _codeEnv.GetUsedQuerySourceVariables(savePairValues, _codeContext.LoopIndexVariable)
.Select(v =>
{
var mr = DeclarableParameter.CreateDeclarableParameterMapExpression(ordering.Expression.Type, v.Type.MakeArrayType());
_codeEnv.AddOutsideLoop(mr);
savePairValues.AddSaver(mr, v);
return(Tuple.Create(v, mr));
})
.ToArray();
// Get back to the results level now, where we do the sorting!
_codeEnv.PopToResultsLevel();
//
// Now, we need to sort and loop over the variables in the map. This is a bit of a messy
// multi-line statement, and it is a compound statement.
//
var sortAndRunLoop = new StatementLoopOverSortedPairValue(mapRecord, ordering.OrderingDirection == OrderingDirection.Asc);
_codeEnv.Add(sortAndRunLoop);
var pindex = sortAndRunLoop.IndexVariable;
var lv = _codeContext.LoopIndexVariable.RawValue;
_codeContext.Add(lv, pindex);
foreach (var savers in otherSavers)
{
var newVarName = sortAndRunLoop.RestoreOtherSaver(savers.Item2);
_codeContext.Add(savers.Item1.RawValue, newVarName);
}
_codeContext.SetLoopVariable(_codeContext.LoopVariable.ReplaceSubExpression(_codeContext.LoopIndexVariable.AsExpression(), pindex), pindex);
}
/// <summary>
/// Add the code to do the pair-wise loop.
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
public void ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
var ro = resultOperator as PairWiseAllResultOperator;
if (ro == null)
throw new ArgumentNullException("Result operator is not of PairWiseAll type");
//
// First, record all the good indicies for this array
//
var arrayRecord = DeclarableParameter.CreateDeclarableParameterArrayExpression(typeof(int));
gc.AddOutsideLoop(arrayRecord);
var recordIndexStatement = new StatementRecordIndicies(ExpressionToCPP.GetExpression(cc.LoopIndexVariable.AsExpression(), gc, cc, container), arrayRecord);
gc.Add(recordIndexStatement);
gc.Pop();
///
/// Next, we create a loop that will mark all the guys as "good" that
/// the pair-wise function. Hopefully the statement below will be efficient and
/// not double-try anything! The lambda we've been passed we have to evaluate - twice -
/// for each, and pass it as a "test" to the statement. It will be some horrendus expression
/// I suppose!
///
var passAll = DeclarableParameter.CreateDeclarableParameterArrayExpression(typeof(bool));
gc.Add(passAll);
var index1 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var index2 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var index1Lookup = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index1); //Expression.ArrayIndex(array, index1);
var index2Lookup = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index2);//Expression.ArrayIndex(array, index2);
var callLambda = Expression.Invoke(ro.Test,
index1Lookup,
index2Lookup
);
var xcheck = new Statements.StatementCheckLoopPairwise(arrayRecord,
index1, index2, passAll);
gc.Add(xcheck);
var test = new Statements.StatementTestLoopPairwise(
passAll,
ExpressionToCPP.GetExpression(callLambda, gc, cc, container));
gc.Add(test);
gc.Pop();
//
// Ok, the result of that will be the array we have here is now filled with the
// "proper" stuff. That is - we have "true" in everthing that is good. So we will
// now just loop over that and apply the index as needed.
//
var goodIndex = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
gc.Add(goodIndex);
var loopOverGood = new Statements.StatementLoopOverGood(arrayRecord, passAll, goodIndex);
gc.Add(loopOverGood);
cc.SetLoopVariable(cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), goodIndex), goodIndex);
}
/// <summary>
/// Add the code to do the pair-wise loop.
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
public void ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
var ro = resultOperator as PairWiseAllResultOperator;
if (ro == null)
{
throw new ArgumentNullException("Result operator is not of PairWiseAll type");
}
//
// First, record all the good indicies for this array
//
var arrayRecord = DeclarableParameter.CreateDeclarableParameterArrayExpression(typeof(int));
gc.AddOutsideLoop(arrayRecord);
var recordIndexStatement = new StatementRecordIndicies(ExpressionToCPP.GetExpression(cc.LoopIndexVariable.AsExpression(), gc, cc, container), arrayRecord);
gc.Add(recordIndexStatement);
gc.Pop();
///
/// Next, we create a loop that will mark all the guys as "good" that
/// the pair-wise function. Hopefully the statement below will be efficient and
/// not double-try anything! The lambda we've been passed we have to evaluate - twice -
/// for each, and pass it as a "test" to the statement. It will be some horrendus expression
/// I suppose!
///
var passAll = DeclarableParameter.CreateDeclarableParameterArrayExpression(typeof(bool));
gc.Add(passAll);
var index1 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var index2 = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
var index1Lookup = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index1); //Expression.ArrayIndex(array, index1);
var index2Lookup = cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), index2); //Expression.ArrayIndex(array, index2);
var callLambda = Expression.Invoke(ro.Test,
index1Lookup,
index2Lookup
);
var xcheck = new Statements.StatementCheckLoopPairwise(arrayRecord,
index1, index2, passAll);
gc.Add(xcheck);
var test = new Statements.StatementTestLoopPairwise(
passAll,
ExpressionToCPP.GetExpression(callLambda, gc, cc, container));
gc.Add(test);
gc.Pop();
//
// Ok, the result of that will be the array we have here is now filled with the
// "proper" stuff. That is - we have "true" in everthing that is good. So we will
// now just loop over that and apply the index as needed.
//
var goodIndex = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
gc.Add(goodIndex);
var loopOverGood = new Statements.StatementLoopOverGood(arrayRecord, passAll, goodIndex);
gc.Add(loopOverGood);
cc.SetLoopVariable(cc.LoopVariable.ReplaceSubExpression(cc.LoopIndexVariable.AsExpression(), goodIndex), goodIndex);
}
/// <summary>
/// Code up the min/max result operators. We run the loop out, and then
/// we return the result whatever it is. We only work when the type is
/// something simple we can deal with!
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <param name="_codeContext"></param>
/// <param name="container"></param>
/// <returns></returns>
public Expression ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode gc, ICodeContext cc, CompositionContainer container)
{
///
/// Some argument checking
///
if (cc == null)
{
throw new ArgumentNullException("cc");
}
if (gc == null)
{
throw new ArgumentNullException("gc");
}
if (gc.Depth == 1)
{
throw new ArgumentException("The Max/Min operators can't be used as result operators for a query - they can only be used in a sub-query");
}
///
/// Is it min or max?
///
var minOperator = resultOperator as MinResultOperator;
var maxOperator = resultOperator as MaxResultOperator;
if (minOperator == null && maxOperator == null)
{
throw new InvalidOperationException("Should always have min or max operator!");
}
bool doMax = maxOperator != null;
bool returnDefaultValue = false;
if (doMax)
{
returnDefaultValue = maxOperator.ReturnDefaultWhenEmpty;
}
else
{
returnDefaultValue = minOperator.ReturnDefaultWhenEmpty;
}
///
/// Next, look at the type of the current result that is running.
///
var valueExpr = queryModel.SelectClause.Selector;
if (!TimeCanBeCompared(valueExpr.Type))
{
throw new ArgumentException(string.Format("I don't know how to fix the min or max of a sequence of '{0}'s", cc.LoopVariable.Type.Name));
}
///
/// Now, declare two variables, one bool which gets set when we get the first value,
/// and the other to hold the min/max value! Note that we initalize the variable to
/// the proper type. We don't declare minmax holder - as it may end up be used
/// externally.
///
var vIsFilled = DeclarableParameter.CreateDeclarableParameterExpression(typeof(bool));
vIsFilled.InitialValue = new ValSimple("false", typeof(bool), null);
var vMaxMin = DeclarableParameter.CreateDeclarableParameterExpression(valueExpr.Type);
vMaxMin.InitialValue = new ValSimple("0", typeof(int), null);
gc.AddOutsideLoop(vIsFilled);
///
/// The expression we want to mimize or maximize
///
var exprToMinOrMaximize = ExpressionToCPP.GetExpression(valueExpr, gc, cc, container);
///
/// Now, we just have to put the x-checks in there.
///
var ifStatement = new Statements.StatementMinMaxTest(vIsFilled, vMaxMin, exprToMinOrMaximize, doMax);
gc.Add(ifStatement);
return(vMaxMin);
}
public Expression ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel,
IGeneratedQueryCode gc, ICodeContext cc,
CompositionContainer container)
{
if (resultOperator == null)
throw new ArgumentNullException("resultOperator");
if (cc == null)
throw new ArgumentNullException("CodeContext can't be null");
//
// Determine the type of the result operator we are processing and
// anything we need to know about it.
//
Type sumType;
sumType = cc.LoopVariable.Type;
bool doAverage = false;
if (resultOperator is SumResultOperator)
{
doAverage = false;
}
else
{
doAverage = true;
}
//
// We only know how to sum basic types
//
if (!sumType.IsNumberType())
{
throw new InvalidOperationException(string.Format("Do not know how to generate C++ to sum type {0}.", sumType.Name));
}
var accumulator = DeclarableParameter.CreateDeclarableParameterExpression(sumType);
accumulator.SetInitialValue("0");
//
// Now, in the loop we are currently in, we do the "add".
//
var add = Expression.Add(accumulator, cc.LoopVariable);
var addResolved = ExpressionToCPP.GetExpression(add, gc, cc, container);
gc.Add(new StatementAggregate(accumulator, addResolved));
//
// The sum will just be this accumulator - so return it.
//
if (!doAverage)
return accumulator;
//
// If this is a average then we need to add a simple count on. Further, we need to declare
// everything we are going to need for later.
//
var counter = DeclarableParameter.CreateDeclarableParameterExpression(typeof(int));
counter.SetInitialValue("0");
gc.AddOutsideLoop(counter);
gc.AddOutsideLoop(accumulator);
var incbyone = Expression.Add(counter, Expression.Constant(1));
gc.Add(new StatementAggregate(counter, ExpressionToCPP.GetExpression(incbyone, gc, cc, container)));
// It is an error to average a sequence with no elements. So we need to throw a C++ exception. We need to pop up out of the loop in order
// to do this.
// http://msdn.microsoft.com/en-us/library/bb354760.aspx (for specs on Average on this).
var testForSomething = Expression.Equal(counter, Expression.Constant(0));
gc.AddAtResultScope(new StatementThrowIfTrue(ExpressionToCPP.GetExpression(testForSomething, gc, cc, container), "Can't take an average of a null sequence"));
var returnType = DetermineAverageReturnType(sumType);
var faccumulator = Expression.Convert(accumulator, returnType);
var fcount = Expression.Convert(counter, returnType);
var divide = Expression.Divide(faccumulator, fcount);
// We are done with this calculation, so pop up and out.
gc.Pop();
return divide;
}