public override bool GetOptimized(out Path optimizedPath)
{
UnionPath optimizedComponents = new UnionPath(Schema);
bool componentsOptimized = false;
foreach (Path componentPath in ComponentPaths)
{
Path optimizedComponent;
componentsOptimized |= componentPath.GetOptimized(out optimizedComponent);
optimizedComponents.ComponentPaths.Add(optimizedComponent);
}
if (optimizedComponents.ComponentPaths.Count == 1)
{
optimizedPath = optimizedComponents.ComponentPaths[0];
return(true);
}
// small expression optimization: (###/X | ###/descendant:X) is combined to (###/descendant:X)
if (optimizedComponents.ComponentPaths.Count > 0 && optimizedComponents.ComponentPaths.TransitiveTrue(CanBeJoinedInSteps))
{
optimizedPath = JoinInSteps(optimizedComponents);
return(true);
}
if (componentsOptimized)
{
optimizedPath = optimizedComponents;
return(true);
}
optimizedPath = this;
return(false);
}
private Path JoinInSteps(UnionPath optimizedComponents)
{
SimplePath joined = new SimplePath(Schema);
for (int i = 0; i < ((SimplePath)optimizedComponents.ComponentPaths.First()).Steps.Count; i++)
{
if (optimizedComponents.ComponentPaths.Select(path => ((SimplePath)path).Steps[i]).TransitiveTrue((s1, s2) => s1 == s2))
{
// ale are equal, so take first one
Step imageStep = ((SimplePath)optimizedComponents.ComponentPaths.First()).Steps[i];
joined.AddStep(imageStep.DeepCopy());
}
else
{
Step imageStep = ((SimplePath)optimizedComponents.ComponentPaths.First()).Steps[i];
// they must be joined
Step newStep = new Step()
{
Axis = Axis.descendant, NodeTest = imageStep.NodeTest
};
joined.AddStep(newStep);
}
}
return(joined);
}
public override Path DeepCopy()
{
UnionPath copy = new UnionPath(Schema);
base.FillCopy(copy);
foreach (Path componentPath in ComponentPaths)
{
copy.ComponentPaths.Add(componentPath.DeepCopy());
}
return(copy);
}
