/// <summary>
/// Gets all <see cref="SelectionCandidate"/>s for the <paramref name="demand"/> that are compatible with the current <see cref="Selections"/> state.
/// </summary>
private IEnumerable <SelectionCandidate> GetCompatibleCandidates(SolverDemand demand) => demand.Candidates.Where(candidate =>
{
if (!candidate.IsSuitable)
{
return(false);
}
var nativeImplementation = candidate.Implementation as ExternalImplementation;
// Ensure the candidate does not conflict with restrictions of existing selections
foreach (var restriction in Selections.RestrictionsFor(demand.Requirements.InterfaceUri))
{
// Prevent mixing of 32-bit and 64-bit binaries
if (candidate.Implementation.Architecture.Cpu.Is32Bit() && Selections.Is64Bit)
{
return(false);
}
if (candidate.Implementation.Architecture.Cpu.Is64Bit() && Selections.Is32Bit)
{
return(false);
}
if (restriction.Versions != null && !restriction.Versions.Match(candidate.Version))
{
return(false);
}
if (nativeImplementation != null && !restriction.Distributions.ContainsOrEmpty(nativeImplementation.Distribution))
{
return(false);
}
}
// Ensure the existing selections do not conflict with restrictions of the candidate
foreach (var restriction in candidate.Implementation.GetEffectiveRestrictions())
{
var selection = Selections.GetImplementation(restriction.InterfaceUri);
if (selection != null)
{
if (restriction.Versions != null && !restriction.Versions.Match(selection.Version))
{
return(false);
}
if (nativeImplementation != null && !restriction.Distributions.ContainsOrEmpty(nativeImplementation.Distribution))
{
return(false);
}
}
}
return(true);
});