private static Action <IField, object> BuildFieldBinder(MetadataIdentity metadata, ColumnIdentity column)
{
ParameterExpression fieldParam = Expression.Parameter(typeof(IField));
ParameterExpression valueParam = Expression.Parameter(typeof(object));
IBindingMetadata binding = metadata.GetMetadata <IBindingMetadata>();
Expression bindValue = valueParam;
if (metadata != null)
{
Type sourceType = null;
if (column != null)
{
BindingColumnInfo columnInfo = new BindingColumnInfo()
{
Column = column,
CanBeNull = true,
Metadata = binding,
};
sourceType = binding.Value?.Read(columnInfo)?.ReturnType;
}
BindingValueInfo valueInfo = new BindingValueInfo()
{
CanBeNull = true,
CanBeDbNull = true,
Metadata = binding,
Value = bindValue,
SourceType = sourceType,
TargetType = binding.Type,
};
bindValue = binding.Value?.Convert?.Invoke(valueInfo) ?? valueParam;
}
MethodInfo bindMethod = typeof(IField).GetMethod(nameof(IField.Bind), new[] { typeof(object) });
Expression bindCall = Expression.Call(fieldParam, bindMethod, Expression.Convert(bindValue, typeof(object)));
return(Expression.Lambda <Action <IField, object> >(bindCall, fieldParam, valueParam).Compile());
}
public BufferConverter Compile(MetadataIdentity metadata, ColumnMetadata columnInfo)
{
IBindingMetadata binding = metadata.Lookup <IBindingMetadata>();
ParameterExpression inputParam = Expression.Parameter(typeof(object));
ParameterExpression helperParam = Expression.Parameter(typeof(object));
ParameterExpression helperVariable = this.GetHelperVariable(binding);
Expression value = inputParam;
if (binding != null)
{
Type sourceType = null;
if (columnInfo != null)
{
BindingColumnInfo bindingColumnInfo = new BindingColumnInfo()
{
Column = columnInfo,
CanBeNull = true,
Metadata = binding,
};
sourceType = binding.Value?.Read(bindingColumnInfo)?.ReturnType;
}
BindingValueInfo valueInfo = new BindingValueInfo()
{
CanBeNull = true,
CanBeDbNull = true,
Metadata = binding,
Value = value,
SourceType = sourceType,
TargetType = binding.Type,
Helper = helperVariable,
};
try
{
value = binding.Value?.Convert?.Invoke(valueInfo) ?? inputParam;
}
catch (BindingException)
{
throw;
}
catch (Exception ex)
{
throw BindingException.InvalidCast(binding, ex);
}
}
value = this.GetObjectExpression(value);
if (helperVariable != null)
{
Expression typedParam = Expression.Convert(helperParam, helperVariable.Type);
Expression assignHelper = Expression.Assign(helperVariable, typedParam);
value = Expression.Block(new[] { helperVariable }, assignHelper, value);
}
BufferInternalConverter innerFunc = Expression.Lambda <BufferInternalConverter>(value, inputParam, helperParam).Compile();
object helperObject = binding?.Helper?.Object;
return(value => innerFunc(value, helperObject));
}