/// <summary>
/// Returns the <see cref="JsonPlusObjectMember"/> associated with the <see cref="JsonPlusPath"/> specified.
/// </summary>
/// <param name="path">The path to the member to return.</param>
/// <param name="result">If the member is returned successfully, this parameter will contain the result <see cref="JsonPlusObjectMember"/>. This parameter should be passed uninitialized.</param>
/// <returns>`true` if the <see cref="JsonPlusObject"/> contains the <see cref="JsonPlusObjectMember"/> associated with <paramref name="path"/>. Otherwise, `false`.</returns>
public bool TryGetMember(JsonPlusPath path, out JsonPlusObjectMember result)
{
result = null;
if (path == null || path.Count == 0)
{
return(false);
}
int pathIndex = 0;
JsonPlusObject currentObject = this;
while (true)
{
string key = path[pathIndex];
if (!currentObject.TryGetValue(key, out var field))
{
return(false);
}
if (pathIndex >= path.Count - 1)
{
result = field;
return(true);
}
if (field.Type != JsonPlusType.Object)
{
return(false);
}
currentObject = field.GetObject();
pathIndex = pathIndex + 1;
}
}
private JsonPlusValue ResolveSubstitution(JsonPlusSubstitution sub)
{
JsonPlusObjectMember subField = sub.ParentMember;
// first case, this substitution is a direct self-reference
if (sub.Path == sub.GetMemberPath())
{
IJsonPlusNode parent = sub.Parent;
while (parent is JsonPlusValue)
{
parent = parent.Parent;
}
// Fail case
if (parent is JsonPlusArray)
{
throw new JsonPlusException(RS.SelfRefSubstitutionInArray);
}
// try to resolve substitution by looking backward in the field assignment stack
return(subField.OlderValueThan(sub));
}
// need to recursively get full path
JsonPlusPath fieldPath = subField.GetMemberPath();
// second case, the substitution references a field child in the past
if (sub.Path.IsChildPathOf(fieldPath))
{
JsonPlusValue olderValue = subField.OlderValueThan(sub);
if ((olderValue != null) &&
(olderValue.Type == JsonPlusType.Object))
{
int difLength = sub.Path.Count - fieldPath.Count;
JsonPlusPath deltaPath = sub.Path.SubPath(sub.Path.Count - difLength, difLength);
JsonPlusObject olderObject = olderValue.GetObject();
if (olderObject.TryGetValue(deltaPath, out JsonPlusValue innerValue))
{
return(innerValue.Type == JsonPlusType.Object ? innerValue : null);
}
}
}
// Detect invalid parent-referencing substitution
if (fieldPath.IsChildPathOf(sub.Path))
{
throw new JsonPlusException(RS.SubstitutionRefDirectParentError);
}
// Detect invalid cyclic reference loop
if (IsValueCyclic(subField, sub))
{
throw new JsonPlusException(RS.CyclicSubstitutionLoop);
}
// third case, regular substitution
_root.GetObject().TryGetValue(sub.Path, out JsonPlusValue field);
return(field);
}
/// <summary>
/// Returns the <see cref="JsonPlusObjectMember"/> associated with the <see cref="JsonPlusPath"/> specified.
/// </summary>
/// <param name="path">The path to the field to return.</param>
/// <exception cref="ArgumentNullException">The <paramref name="path"/> specified is `null`.</exception>
/// <exception cref="ArgumentException">The <paramref name="path"/> specified is empty.</exception>
/// <exception cref="KeyNotFoundException">The key does not exist in the <see cref="JsonPlusObject"/> instance.</exception>
/// <exception cref="JsonPlusException">The <paramref name="path"/> specified is invalid.</exception>
/// <returns>The <see cref="JsonPlusObjectMember"/> associated with <paramref name="path"/>.</returns>
public JsonPlusObjectMember GetMember(JsonPlusPath path)
{
if (path == null)
{
throw new ArgumentNullException(nameof(path));
}
if (path.Count == 0)
{
throw new ArgumentException(RS.PathIsEmpty, nameof(path));
}
int pathIndex = 0;
JsonPlusObject currentObject = this;
while (true)
{
string key = path[pathIndex];
if (!currentObject.TryGetValue(key, out JsonPlusObjectMember field))
{
throw new KeyNotFoundException(string.Format(RS.ObjectMemberNotFoundByPath,
key, new JsonPlusPath(path.GetRange(0, pathIndex + 1)).Value));
}
if (pathIndex >= path.Count - 1)
{
return(field);
}
if (field.Type != JsonPlusType.Object)
{
throw new JsonPlusException(string.Format(RS.ObjectMemberInPathNotObject,
new JsonPlusPath(path.GetRange(0, pathIndex + 1)).Value));
}
currentObject = field.GetObject();
pathIndex = pathIndex + 1;
}
}
