/// <summary>
/// Reads the content of the Json file.
/// </summary>
/// <param name="filePath">path to the file</param>
/// <returns><see cref="IEnumerable{JsonItem}"/> for all contained items.</returns>
/// <remarks>An <see cref="Utf8JsonReader"/> instance cannot be created when using yield return iterator block.</remarks>
public static IEnumerable <JsonItem> Parse(string filePath)
{
var rootItems = new List <JsonItem>();
var buffer = File.ReadAllBytes(filePath);
var itemStack = new Stack <JsonItem>();
JsonItem currentProperty = null;
var byteSequence = new ReadOnlySequence <byte>(buffer, 0, buffer.Length);
var reader = new Utf8JsonReader(byteSequence);
while (reader.Read())
{
switch (reader.TokenType)
{
case JsonTokenType.StartObject:
var newElement = new JsonElement();
if (null != currentProperty)
{
currentProperty.AddValue(newElement);
}
else if (0 < itemStack.Count)
{
var objectParent = (JsonItemArray)itemStack.Peek();
objectParent.AddValue(newElement);
}
itemStack.Push(newElement);
currentProperty = null;
break;
case JsonTokenType.EndObject:
var poppedObject = itemStack.Pop();
if (0 == itemStack.Count)
{
rootItems.Add(poppedObject);
}
break;
case JsonTokenType.StartArray:
var newArray = new JsonItemArray();
if (null != currentProperty)
{
currentProperty.AddValue(newArray);
}
else if (0 < itemStack.Count)
{
var arrayParent = (JsonItemArray)itemStack.Peek();
arrayParent.AddValue(newArray);
}
itemStack.Push(newArray);
currentProperty = null;
break;
case JsonTokenType.EndArray:
var poppedArray = itemStack.Pop();
if (0 == itemStack.Count)
{
rootItems.Add(poppedArray);
}
break;
case JsonTokenType.PropertyName:
var propertyName = reader.GetString();
var propertyParent = (JsonElement)itemStack.Peek();
currentProperty = propertyParent.CreateProperty(propertyName);
break;
case JsonTokenType.String:
var stringValue = reader.GetString();
if (null != currentProperty)
{
currentProperty.AddValue(stringValue);
currentProperty = null;
}
else
{
var stringParent = itemStack.Peek();
stringParent.AddValue(stringValue);
}
break;
case JsonTokenType.Number:
var doubleValue = reader.GetDouble();
if (null != currentProperty)
{
currentProperty.AddValue(doubleValue);
currentProperty = null;
}
else
{
var doubleParent = itemStack.Peek();
doubleParent.AddValue(doubleValue);
}
break;
}
}
return(rootItems);
}
