/// <summary>
/// Expansion Algorithm
/// http://json-ld.org/spec/latest/json-ld-api/#expansion-algorithm
/// </summary>
/// <param name="activeCtx"></param>
/// <param name="activeProperty"></param>
/// <param name="element"></param>
/// <returns></returns>
/// <exception cref="JsonLdError">JsonLdError</exception>
/// <exception cref="JsonLD.Core.JsonLdError"></exception>
public virtual JToken Expand(Context activeCtx, string activeProperty, JToken element
)
{
// 1)
if (element.IsNull())
{
return null;
}
// 3)
if (element is JArray)
{
// 3.1)
JArray result = new JArray();
// 3.2)
foreach (JToken item in (JArray)element)
{
// 3.2.1)
JToken v = Expand(activeCtx, activeProperty, item);
// 3.2.2)
if (("@list".Equals(activeProperty) || "@list".Equals(activeCtx.GetContainer(activeProperty
))) && (v is JArray || (v is JObject && ((IDictionary<string, JToken>)v).ContainsKey
("@list"))))
{
throw new JsonLdError(JsonLdError.Error.ListOfLists, "lists of lists are not permitted."
);
}
else
{
// 3.2.3)
if (!v.IsNull())
{
if (v is JArray)
{
JsonLD.Collections.AddAll(result, (JArray)v);
}
else
{
result.Add(v);
}
}
}
}
// 3.3)
return result;
}
else
{
// 4)
if (element is JObject)
{
// access helper
IDictionary<string, JToken> elem = (JObject)element;
// 5)
if (elem.ContainsKey("@context"))
{
activeCtx = activeCtx.Parse(elem["@context"]);
}
// 6)
JObject result = new JObject();
// 7)
JArray keys = new JArray(element.GetKeys());
keys.SortInPlace();
foreach (string key in keys)
{
JToken value = elem[key];
// 7.1)
if (key.Equals("@context"))
{
continue;
}
// 7.2)
string expandedProperty = activeCtx.ExpandIri(key, false, true, null, null);
JToken expandedValue = null;
// 7.3)
if (expandedProperty == null || (!expandedProperty.Contains(":") && !JsonLdUtils.IsKeyword
(expandedProperty)))
{
continue;
}
// 7.4)
if (JsonLdUtils.IsKeyword(expandedProperty))
{
// 7.4.1)
if ("@reverse".Equals(activeProperty))
{
throw new JsonLdError(JsonLdError.Error.InvalidReversePropertyMap, "a keyword cannot be used as a @reverse propery"
);
}
// 7.4.2)
if (result.ContainsKey(expandedProperty))
{
throw new JsonLdError(JsonLdError.Error.CollidingKeywords, expandedProperty + " already exists in result"
);
}
// 7.4.3)
if ("@id".Equals(expandedProperty))
{
if (!(value.Type == JTokenType.String))
{
throw new JsonLdError(JsonLdError.Error.InvalidIdValue, "value of @id must be a string"
);
}
expandedValue = activeCtx.ExpandIri((string)value, true, false, null, null);
}
else
{
// 7.4.4)
if ("@type".Equals(expandedProperty))
{
if (value is JArray)
{
expandedValue = new JArray();
foreach (JToken v in (JArray)value)
{
if (v.Type != JTokenType.String)
{
throw new JsonLdError(JsonLdError.Error.InvalidTypeValue, "@type value must be a string or array of strings"
);
}
((JArray)expandedValue).Add(activeCtx.ExpandIri((string)v, true, true, null
, null));
}
}
else
{
if (value.Type == JTokenType.String)
{
expandedValue = activeCtx.ExpandIri((string)value, true, true, null, null);
}
else
{
// TODO: SPEC: no mention of empty map check
if (value is JObject)
{
if (((JObject)value).Count != 0)
{
throw new JsonLdError(JsonLdError.Error.InvalidTypeValue, "@type value must be a an empty object for framing"
);
}
expandedValue = value;
}
else
{
throw new JsonLdError(JsonLdError.Error.InvalidTypeValue, "@type value must be a string or array of strings"
);
}
}
}
}
else
{
// 7.4.5)
if ("@graph".Equals(expandedProperty))
{
expandedValue = Expand(activeCtx, "@graph", value);
}
else
{
// 7.4.6)
if ("@value".Equals(expandedProperty))
{
if (!value.IsNull() && (value is JObject || value is JArray))
{
throw new JsonLdError(JsonLdError.Error.InvalidValueObjectValue, "value of " + expandedProperty
+ " must be a scalar or null");
}
expandedValue = value;
if (expandedValue.IsNull())
{
result["@value"] = null;
continue;
}
}
else
{
// 7.4.7)
if ("@language".Equals(expandedProperty))
{
if (!(value.Type == JTokenType.String))
{
throw new JsonLdError(JsonLdError.Error.InvalidLanguageTaggedString, "Value of "
+ expandedProperty + " must be a string");
}
expandedValue = ((string)value).ToLower();
}
else
{
// 7.4.8)
if ("@index".Equals(expandedProperty))
{
if (!(value.Type == JTokenType.String))
{
throw new JsonLdError(JsonLdError.Error.InvalidIndexValue, "Value of " + expandedProperty
+ " must be a string");
}
expandedValue = value;
}
else
{
// 7.4.9)
if ("@list".Equals(expandedProperty))
{
// 7.4.9.1)
if (activeProperty == null || "@graph".Equals(activeProperty))
{
continue;
}
// 7.4.9.2)
expandedValue = Expand(activeCtx, activeProperty, value);
// NOTE: step not in the spec yet
if (!(expandedValue is JArray))
{
JArray tmp = new JArray();
tmp.Add(expandedValue);
expandedValue = tmp;
}
// 7.4.9.3)
foreach (JToken o in (JArray)expandedValue)
{
if (o is JObject && ((JObject)o).ContainsKey("@list"))
{
throw new JsonLdError(JsonLdError.Error.ListOfLists, "A list may not contain another list"
);
}
}
}
else
{
// 7.4.10)
if ("@set".Equals(expandedProperty))
{
expandedValue = Expand(activeCtx, activeProperty, value);
}
else
{
// 7.4.11)
if ("@reverse".Equals(expandedProperty))
{
if (!(value is JObject))
{
throw new JsonLdError(JsonLdError.Error.InvalidReverseValue, "@reverse value must be an object"
);
}
// 7.4.11.1)
expandedValue = Expand(activeCtx, "@reverse", value);
// NOTE: algorithm assumes the result is a map
// 7.4.11.2)
if (((IDictionary<string, JToken>)expandedValue).ContainsKey("@reverse"))
{
JObject reverse = (JObject)((JObject)expandedValue)["@reverse"];
foreach (string property in reverse.GetKeys())
{
JToken item = reverse[property];
// 7.4.11.2.1)
if (!result.ContainsKey(property))
{
result[property] = new JArray();
}
// 7.4.11.2.2)
if (item is JArray)
{
JsonLD.Collections.AddAll(((JArray)result[property]), (JArray)item);
}
else
{
((JArray)result[property]).Add(item);
}
}
}
// 7.4.11.3)
if (((JObject)expandedValue).Count > (((JObject)expandedValue).ContainsKey("@reverse") ? 1 : 0))
{
// 7.4.11.3.1)
if (!result.ContainsKey("@reverse"))
{
result["@reverse"] = new JObject();
}
// 7.4.11.3.2)
JObject reverseMap = (JObject)result["@reverse"];
// 7.4.11.3.3)
foreach (string property in expandedValue.GetKeys())
{
if ("@reverse".Equals(property))
{
continue;
}
// 7.4.11.3.3.1)
JArray items = (JArray)((JObject)expandedValue)[property];
foreach (JToken item in items)
{
// 7.4.11.3.3.1.1)
if (item is JObject && (((JObject)item).ContainsKey("@value") || ((JObject)item).ContainsKey("@list")))
{
throw new JsonLdError(JsonLdError.Error.InvalidReversePropertyValue);
}
// 7.4.11.3.3.1.2)
if (!reverseMap.ContainsKey(property))
{
reverseMap[property] = new JArray();
}
// 7.4.11.3.3.1.3)
((JArray)reverseMap[property]).Add(item);
}
}
}
// 7.4.11.4)
continue;
}
else
{
// TODO: SPEC no mention of @explicit etc in spec
if ("@explicit".Equals(expandedProperty) || "@default".Equals(expandedProperty) ||
"@embed".Equals(expandedProperty) || "@embedChildren".Equals(expandedProperty)
|| "@omitDefault".Equals(expandedProperty))
{
expandedValue = Expand(activeCtx, expandedProperty, value);
}
}
}
}
}
}
}
}
}
}
// 7.4.12)
if (!expandedValue.IsNull())
{
result[expandedProperty] = expandedValue;
}
// 7.4.13)
continue;
}
else
{
// 7.5
if ("@language".Equals(activeCtx.GetContainer(key)) && value is JObject)
{
// 7.5.1)
expandedValue = new JArray();
// 7.5.2)
foreach (string language in value.GetKeys())
{
JToken languageValue = ((IDictionary<string, JToken>)value)[language];
// 7.5.2.1)
if (!(languageValue is JArray))
{
JToken tmp = languageValue;
languageValue = new JArray();
((JArray)languageValue).Add(tmp);
}
// 7.5.2.2)
foreach (JToken item in (JArray)languageValue)
{
// 7.5.2.2.1)
if (!(item.Type == JTokenType.String))
{
throw new JsonLdError(JsonLdError.Error.InvalidLanguageMapValue, "Expected " + item
.ToString() + " to be a string");
}
// 7.5.2.2.2)
JObject tmp = new JObject();
tmp["@value"] = item;
tmp["@language"] = language.ToLower();
((JArray)expandedValue).Add(tmp);
}
}
}
else
{
// 7.6)
if ("@index".Equals(activeCtx.GetContainer(key)) && value is JObject)
{
// 7.6.1)
expandedValue = new JArray();
// 7.6.2)
JArray indexKeys = new JArray(value.GetKeys());
indexKeys.SortInPlace();
foreach (string index in indexKeys)
{
JToken indexValue = ((JObject)value)[index];
// 7.6.2.1)
if (!(indexValue is JArray))
{
JToken tmp = indexValue;
indexValue = new JArray();
((JArray)indexValue).Add(tmp);
}
// 7.6.2.2)
indexValue = Expand(activeCtx, key, indexValue);
// 7.6.2.3)
foreach (JObject item in (JArray)indexValue)
{
// 7.6.2.3.1)
if (!item.ContainsKey("@index"))
{
item["@index"] = index;
}
// 7.6.2.3.2)
((JArray)expandedValue).Add(item);
}
}
}
else
{
// 7.7)
expandedValue = Expand(activeCtx, key, value);
}
}
}
// 7.8)
if (expandedValue.IsNull())
{
continue;
}
// 7.9)
if ("@list".Equals(activeCtx.GetContainer(key)))
{
if (!(expandedValue is JObject) || !((JObject)expandedValue).ContainsKey("@list"))
{
JToken tmp = expandedValue;
if (!(tmp is JArray))
{
tmp = new JArray();
((JArray)tmp).Add(expandedValue);
}
expandedValue = new JObject();
((JObject)expandedValue)["@list"] = tmp;
}
}
// 7.10)
if (activeCtx.IsReverseProperty(key))
{
// 7.10.1)
if (!result.ContainsKey("@reverse"))
{
result["@reverse"] = new JObject();
}
// 7.10.2)
JObject reverseMap = (JObject)result["@reverse"];
// 7.10.3)
if (!(expandedValue is JArray))
{
JToken tmp = expandedValue;
expandedValue = new JArray();
((JArray)expandedValue).Add(tmp);
}
// 7.10.4)
foreach (JToken item in (JArray)expandedValue)
{
// 7.10.4.1)
if (item is JObject && (((JObject)item).ContainsKey("@value") || ((JObject)item).ContainsKey("@list")))
{
throw new JsonLdError(JsonLdError.Error.InvalidReversePropertyValue);
}
// 7.10.4.2)
if (!reverseMap.ContainsKey(expandedProperty))
{
reverseMap[expandedProperty] = new JArray();
}
// 7.10.4.3)
if (item is JArray)
{
JsonLD.Collections.AddAll(((JArray)reverseMap[expandedProperty]), (JArray)item);
}
else
{
((JArray)reverseMap[expandedProperty]).Add(item);
}
}
}
else
{
// 7.11)
// 7.11.1)
if (!result.ContainsKey(expandedProperty))
{
result[expandedProperty] = new JArray();
}
// 7.11.2)
if (expandedValue is JArray)
{
JsonLD.Collections.AddAll(((JArray)result[expandedProperty]), (JArray)expandedValue);
}
else
{
((JArray)result[expandedProperty]).Add(expandedValue);
}
}
}
// 8)
if (result.ContainsKey("@value"))
{
// 8.1)
// TODO: is this method faster than just using containsKey for
// each?
ICollection<string> keySet = new HashSet<string>(result.GetKeys());
keySet.Remove("@value");
keySet.Remove("@index");
bool langremoved = keySet.Remove("@language");
bool typeremoved = keySet.Remove("@type");
if ((langremoved && typeremoved) || !keySet.IsEmpty())
{
throw new JsonLdError(JsonLdError.Error.InvalidValueObject, "value object has unknown keys"
);
}
// 8.2)
JToken rval = result["@value"];
if (rval.IsNull())
{
// nothing else is possible with result if we set it to
// null, so simply return it
return null;
}
// 8.3)
if (!(rval.Type == JTokenType.String) && result.ContainsKey("@language"))
{
throw new JsonLdError(JsonLdError.Error.InvalidLanguageTaggedValue, "when @language is used, @value must be a string"
);
}
else
{
// 8.4)
if (result.ContainsKey("@type"))
{
// TODO: is this enough for "is an IRI"
if (!(result["@type"].Type == JTokenType.String) || ((string)result["@type"]).StartsWith("_:") ||
!((string)result["@type"]).Contains(":"))
{
throw new JsonLdError(JsonLdError.Error.InvalidTypedValue, "value of @type must be an IRI"
);
}
}
}
}
else
{
// 9)
if (result.ContainsKey("@type"))
{
JToken rtype = result["@type"];
if (!(rtype is JArray))
{
JArray tmp = new JArray();
tmp.Add(rtype);
result["@type"] = tmp;
}
}
else
{
// 10)
if (result.ContainsKey("@set") || result.ContainsKey("@list"))
{
// 10.1)
if (result.Count > (result.ContainsKey("@index") ? 2 : 1))
{
throw new JsonLdError(JsonLdError.Error.InvalidSetOrListObject, "@set or @list may only contain @index"
);
}
// 10.2)
if (result.ContainsKey("@set"))
{
// result becomes an array here, thus the remaining checks
// will never be true from here on
// so simply return the value rather than have to make
// result an object and cast it with every
// other use in the function.
return result["@set"];
}
}
}
}
// 11)
if (result.ContainsKey("@language") && result.Count == 1)
{
result = null;
}
// 12)
if (activeProperty == null || "@graph".Equals(activeProperty))
{
// 12.1)
if (result != null && (result.Count == 0 || result.ContainsKey("@value") || result
.ContainsKey("@list")))
{
result = null;
}
else
{
// 12.2)
if (result != null && result.ContainsKey("@id") && result.Count == 1)
{
result = null;
}
}
}
// 13)
return result;
}
else
{
// 2) If element is a scalar
// 2.1)
if (activeProperty == null || "@graph".Equals(activeProperty))
{
return null;
}
return activeCtx.ExpandValue(activeProperty, element);
}
}
}