private static object ResolveValue(BindingContext context, object instance, ChainSegment chainSegment)
{
object resolvedValue;
if (chainSegment.IsVariable)
{
return(context.TryGetContextVariable(chainSegment, out resolvedValue)
? resolvedValue
: UndefinedBindingResult.Create(chainSegment));
}
if (chainSegment.IsThis)
{
return(instance);
}
if (context.TryGetVariable(chainSegment, out resolvedValue) ||
TryAccessMember(instance, chainSegment, context.Configuration, out resolvedValue))
{
return(resolvedValue);
}
if (chainSegment.IsValue && context.TryGetContextVariable(chainSegment, out resolvedValue))
{
return(resolvedValue);
}
return(UndefinedBindingResult.Create(chainSegment));
}
private static ChainSegment ResolveMemberName(object instance, ChainSegment memberName,
ICompiledHandlebarsConfiguration configuration)
{
var resolver = configuration.ExpressionNameResolver;
if (resolver == null)
{
return(memberName);
}
return(resolver.ResolveExpressionName(instance, memberName.TrimmedValue));
}
internal static bool TryAccessMember(object instance, ChainSegment chainSegment, ICompiledHandlebarsConfiguration configuration, out object value)
{
if (instance == null)
{
value = UndefinedBindingResult.Create(chainSegment);
return(false);
}
chainSegment = ResolveMemberName(instance, chainSegment, configuration);
value = null;
return(ObjectDescriptor.TryCreate(instance, configuration, out var descriptor) &&
descriptor.MemberAccessor.TryGetValue(instance, chainSegment, out value));
}
private static IReadOnlyList <ChainSegment> GetPathChain(Substring segmentString)
{
var insideEscapeBlock = false;
var pathChainParts = Substring.Split(segmentString, '.', StringSplitOptions.RemoveEmptyEntries);
if (pathChainParts.Count == 0 && segmentString == ".")
{
return new[] { ChainSegment.Create("this") }
}
;
var chainSegments = new List <ChainSegment>();
var count = pathChainParts.Count;
for (int index = 0; index < count; index++)
{
var next = pathChainParts[index];
if (insideEscapeBlock)
{
if (next.EndsWith(']'))
{
insideEscapeBlock = false;
}
chainSegments[chainSegments.Count - 1] = ChainSegment.Create($"{chainSegments[chainSegments.Count - 1]}.{next.ToString()}");
continue;
}
if (next.StartsWith('['))
{
insideEscapeBlock = true;
}
if (next.EndsWith(']'))
{
insideEscapeBlock = false;
}
chainSegments.Add(ChainSegment.Create(next.ToString()));
}
return(chainSegments);
}
private static IEnumerable <ChainSegment> GetPathChain(string segmentString)
{
var insideEscapeBlock = false;
var pathChainParts = segmentString.Split(new[] { '.' }, StringSplitOptions.RemoveEmptyEntries);
if (pathChainParts.Length == 0 && segmentString == ".")
{
return new[] { ChainSegment.Create("this") }
}
;
var pathChain = pathChainParts.Aggregate(new List <ChainSegment>(), (list, next) =>
{
if (insideEscapeBlock)
{
if (next.EndsWith("]"))
{
insideEscapeBlock = false;
}
list[list.Count - 1] = ChainSegment.Create($"{list[list.Count - 1]}.{next}");
return(list);
}
if (next.StartsWith("["))
{
insideEscapeBlock = true;
}
if (next.EndsWith("]"))
{
insideEscapeBlock = false;
}
list.Add(ChainSegment.Create(next));
return(list);
});
return(pathChain);
}