public static void RunSample()
{
Console.WriteLine("**Utf8JsonReader Sample***");
var jsonBytes = File.ReadAllBytes("sample.json");
var jsonSpan = jsonBytes.AsSpan();
var json = new System.Text.Json.Utf8JsonReader(jsonSpan);
while (json.Read())
{
Console.WriteLine(GetTokenDesc(json));
}
}
private static void ReadValueCore(JsonSerializerOptions options, ref Utf8JsonReader reader, ref ReadStack readStack)
{
JsonReaderState state = reader.CurrentState;
CheckSupportedOptions(state.Options, nameof(reader));
// Value copy to overwrite the ref on an exception and undo the destructive reads.
Utf8JsonReader restore = reader;
ReadOnlySpan <byte> valueSpan = default;
ReadOnlySequence <byte> valueSequence = default;
try
{
switch (reader.TokenType)
{
// A new reader was created and has never been read,
// so we need to move to the first token.
// (or a reader has terminated and we're about to throw)
case JsonTokenType.None:
// Using a reader loop the caller has identified a property they wish to
// hydrate into a JsonDocument. Move to the value first.
case JsonTokenType.PropertyName:
{
if (!reader.Read())
{
ThrowHelper.ThrowJsonReaderException(ref reader, ExceptionResource.ExpectedOneCompleteToken);
}
break;
}
}
switch (reader.TokenType)
{
// Any of the "value start" states are acceptable.
case JsonTokenType.StartObject:
case JsonTokenType.StartArray:
{
long startingOffset = reader.TokenStartIndex;
if (!reader.TrySkip())
{
ThrowHelper.ThrowJsonReaderException(ref reader, ExceptionResource.NotEnoughData);
}
long totalLength = reader.BytesConsumed - startingOffset;
ReadOnlySequence <byte> sequence = reader.OriginalSequence;
if (sequence.IsEmpty)
{
valueSpan = reader.OriginalSpan.Slice(
checked ((int)startingOffset),
checked ((int)totalLength));
}
else
{
valueSequence = sequence.Slice(startingOffset, totalLength);
}
Debug.Assert(
reader.TokenType == JsonTokenType.EndObject ||
reader.TokenType == JsonTokenType.EndArray);
break;
}
// Single-token values
case JsonTokenType.Number:
case JsonTokenType.True:
case JsonTokenType.False:
case JsonTokenType.Null:
{
if (reader.HasValueSequence)
{
valueSequence = reader.ValueSequence;
}
else
{
valueSpan = reader.ValueSpan;
}
break;
}
// String's ValueSequence/ValueSpan omits the quotes, we need them back.
case JsonTokenType.String:
{
ReadOnlySequence <byte> sequence = reader.OriginalSequence;
if (sequence.IsEmpty)
{
// Since the quoted string fit in a ReadOnlySpan originally
// the contents length plus the two quotes can't overflow.
int payloadLength = reader.ValueSpan.Length + 2;
Debug.Assert(payloadLength > 1);
ReadOnlySpan <byte> readerSpan = reader.OriginalSpan;
Debug.Assert(
readerSpan[(int)reader.TokenStartIndex] == (byte)'"',
$"Calculated span starts with {readerSpan[(int)reader.TokenStartIndex]}");
Debug.Assert(
readerSpan[(int)reader.TokenStartIndex + payloadLength - 1] == (byte)'"',
$"Calculated span ends with {readerSpan[(int)reader.TokenStartIndex + payloadLength - 1]}");
valueSpan = readerSpan.Slice((int)reader.TokenStartIndex, payloadLength);
}
else
{
long payloadLength = 2;
if (reader.HasValueSequence)
{
payloadLength += reader.ValueSequence.Length;
}
else
{
payloadLength += reader.ValueSpan.Length;
}
valueSequence = sequence.Slice(reader.TokenStartIndex, payloadLength);
Debug.Assert(
valueSequence.First.Span[0] == (byte)'"',
$"Calculated sequence starts with {valueSequence.First.Span[0]}");
Debug.Assert(
valueSequence.ToArray()[payloadLength - 1] == (byte)'"',
$"Calculated sequence ends with {valueSequence.ToArray()[payloadLength - 1]}");
}
break;
}
default:
{
byte displayByte;
if (reader.HasValueSequence)
{
displayByte = reader.ValueSequence.First.Span[0];
}
else
{
displayByte = reader.ValueSpan[0];
}
ThrowHelper.ThrowJsonReaderException(
ref reader,
ExceptionResource.ExpectedStartOfValueNotFound,
displayByte);
break;
}
}
}
catch (JsonReaderException ex)
{
reader = restore;
// Re-throw with Path information.
ThrowHelper.ReThrowWithPath(readStack, ex);
}
int length = valueSpan.IsEmpty ? checked ((int)valueSequence.Length) : valueSpan.Length;
byte[] rented = ArrayPool <byte> .Shared.Rent(length);
Span <byte> rentedSpan = rented.AsSpan(0, length);
try
{
if (valueSpan.IsEmpty)
{
valueSequence.CopyTo(rentedSpan);
}
else
{
valueSpan.CopyTo(rentedSpan);
}
var newReader = new Utf8JsonReader(rentedSpan, isFinalBlock: true, state: default);
ReadCore(options, ref newReader, ref readStack);
if (newReader.BytesConsumed != length)
{
state = newReader.CurrentState;
ThrowHelper.ThrowJsonException_DeserializeDataRemaining(length, length - state.BytesConsumed);
}
}
catch (JsonException)
{
reader = restore;
throw;
}
finally
{
rentedSpan.Clear();
ArrayPool <byte> .Shared.Return(rented);
}
}
private static bool TryParseValue(ref Utf8JsonReader reader, out JsonDocument document, bool shouldThrow)
{
JsonReaderState state = reader.CurrentState;
CheckSupportedOptions(state.Options, nameof(reader));
// Value copy to overwrite the ref on an exception and undo the destructive reads.
Utf8JsonReader restore = reader;
ReadOnlySpan <byte> valueSpan = default;
ReadOnlySequence <byte> valueSequence = default;
try
{
switch (reader.TokenType)
{
// A new reader was created and has never been read,
// so we need to move to the first token.
// (or a reader has terminated and we're about to throw)
case JsonTokenType.None:
// Using a reader loop the caller has identified a property they wish to
// hydrate into a JsonDocument. Move to the value first.
case JsonTokenType.PropertyName:
{
if (!reader.Read())
{
if (shouldThrow)
{
ThrowHelper.ThrowJsonReaderException(
ref reader,
ExceptionResource.ExpectedJsonTokens);
}
reader = restore;
document = null;
return(false);
}
break;
}
}
switch (reader.TokenType)
{
// Any of the "value start" states are acceptable.
case JsonTokenType.StartObject:
case JsonTokenType.StartArray:
{
long startingOffset = reader.TokenStartIndex;
// Placeholder until reader.Skip() is written (#33295)
{
int depth = reader.CurrentDepth;
// CurrentDepth rises late and falls fast,
// a payload of "[ 1, 2, 3, 4 ]" will report post-Read()
// CurrentDepth values of { 0, 1, 1, 1, 1, 0 },
// Since we're logically at 0 ([), Read() once and keep
// reading until we've come back down to 0 (]).
do
{
if (!reader.Read())
{
if (shouldThrow)
{
ThrowHelper.ThrowJsonReaderException(
ref reader,
ExceptionResource.ExpectedJsonTokens);
}
reader = restore;
document = null;
return(false);
}
} while (reader.CurrentDepth > depth);
}
long totalLength = reader.BytesConsumed - startingOffset;
ReadOnlySequence <byte> sequence = reader.OriginalSequence;
if (sequence.IsEmpty)
{
valueSpan = reader.OriginalSpan.Slice(
checked ((int)startingOffset),
checked ((int)totalLength));
}
else
{
valueSequence = sequence.Slice(startingOffset, totalLength);
}
Debug.Assert(
reader.TokenType == JsonTokenType.EndObject ||
reader.TokenType == JsonTokenType.EndArray);
break;
}
// Single-token values
case JsonTokenType.Number:
case JsonTokenType.True:
case JsonTokenType.False:
case JsonTokenType.Null:
{
if (reader.HasValueSequence)
{
valueSequence = reader.ValueSequence;
}
else
{
valueSpan = reader.ValueSpan;
}
break;
}
// String's ValueSequence/ValueSpan omits the quotes, we need them back.
case JsonTokenType.String:
{
ReadOnlySequence <byte> sequence = reader.OriginalSequence;
if (sequence.IsEmpty)
{
// Since the quoted string fit in a ReadOnlySpan originally
// the contents length plus the two quotes can't overflow.
int payloadLength = reader.ValueSpan.Length + 2;
Debug.Assert(payloadLength > 1);
ReadOnlySpan <byte> readerSpan = reader.OriginalSpan;
Debug.Assert(
readerSpan[(int)reader.TokenStartIndex] == (byte)'"',
$"Calculated span starts with {readerSpan[(int)reader.TokenStartIndex]}");
Debug.Assert(
readerSpan[(int)reader.TokenStartIndex + payloadLength - 1] == (byte)'"',
$"Calculated span ends with {readerSpan[(int)reader.TokenStartIndex + payloadLength - 1]}");
valueSpan = readerSpan.Slice((int)reader.TokenStartIndex, payloadLength);
}
else
{
long payloadLength = 2;
if (reader.HasValueSequence)
{
payloadLength += reader.ValueSequence.Length;
}
else
{
payloadLength += reader.ValueSpan.Length;
}
valueSequence = sequence.Slice(reader.TokenStartIndex, payloadLength);
Debug.Assert(
valueSequence.First.Span[0] == (byte)'"',
$"Calculated sequence starts with {valueSequence.First.Span[0]}");
Debug.Assert(
valueSequence.ToArray()[payloadLength - 1] == (byte)'"',
$"Calculated sequence ends with {valueSequence.ToArray()[payloadLength - 1]}");
}
break;
}
default:
{
if (shouldThrow)
{
byte displayByte;
if (reader.HasValueSequence)
{
displayByte = reader.ValueSequence.First.Span[0];
}
else
{
displayByte = reader.ValueSpan[0];
}
ThrowHelper.ThrowJsonReaderException(
ref reader,
ExceptionResource.ExpectedStartOfValueNotFound,
displayByte);
}
reader = restore;
document = null;
return(false);
}
}
}
catch
{
reader = restore;
throw;
}
int length = valueSpan.IsEmpty ? checked ((int)valueSequence.Length) : valueSpan.Length;
byte[] rented = ArrayPool <byte> .Shared.Rent(length);
Span <byte> rentedSpan = rented.AsSpan(0, length);
try
{
if (valueSpan.IsEmpty)
{
valueSequence.CopyTo(rentedSpan);
}
else
{
valueSpan.CopyTo(rentedSpan);
}
document = Parse(rented.AsMemory(0, length), state.Options, rented);
return(true);
}
catch
{
// This really shouldn't happen since the document was already checked
// for consistency by Skip. But if data mutations happened just after
// the calls to Read then the copy may not be valid.
rentedSpan.Clear();
ArrayPool <byte> .Shared.Return(rented);
throw;
}
}
private static void ReadCore(
JsonSerializerOptions options,
ref Utf8JsonReader reader,
ref ReadStack readStack)
{
try
{
JsonReaderState initialState = default;
while (true)
{
if (readStack.ReadAhead)
{
// When we're reading ahead we always have to save the state
// as we don't know if the next token is an opening object or
// array brace.
initialState = reader.CurrentState;
}
if (!reader.Read())
{
// Need more data
break;
}
JsonTokenType tokenType = reader.TokenType;
if (JsonHelpers.IsInRangeInclusive(tokenType, JsonTokenType.String, JsonTokenType.False))
{
Debug.Assert(tokenType == JsonTokenType.String || tokenType == JsonTokenType.Number || tokenType == JsonTokenType.True || tokenType == JsonTokenType.False);
HandleValue(tokenType, options, ref reader, ref readStack);
}
else if (tokenType == JsonTokenType.PropertyName)
{
HandlePropertyName(options, ref reader, ref readStack);
}
else if (tokenType == JsonTokenType.StartObject)
{
if (readStack.Current.SkipProperty)
{
readStack.Push();
readStack.Current.Drain = true;
}
else if (readStack.Current.IsProcessingValue)
{
if (!HandleObjectAsValue(tokenType, options, ref reader, ref readStack, ref initialState))
{
// Need more data
break;
}
}
else if (readStack.Current.IsProcessingDictionary || readStack.Current.IsProcessingImmutableDictionary)
{
HandleStartDictionary(options, ref reader, ref readStack);
}
else
{
HandleStartObject(options, ref reader, ref readStack);
}
}
else if (tokenType == JsonTokenType.EndObject)
{
if (readStack.Current.Drain)
{
readStack.Pop();
}
else if (readStack.Current.IsProcessingDictionary || readStack.Current.IsProcessingImmutableDictionary)
{
HandleEndDictionary(options, ref reader, ref readStack);
}
else
{
HandleEndObject(options, ref reader, ref readStack);
}
}
else if (tokenType == JsonTokenType.StartArray)
{
if (!readStack.Current.IsProcessingValue)
{
HandleStartArray(options, ref reader, ref readStack);
}
else if (!HandleObjectAsValue(tokenType, options, ref reader, ref readStack, ref initialState))
{
// Need more data
break;
}
}
else if (tokenType == JsonTokenType.EndArray)
{
HandleEndArray(options, ref reader, ref readStack);
}
else if (tokenType == JsonTokenType.Null)
{
HandleNull(ref reader, ref readStack, options);
}
}
}
catch (JsonReaderException e)
{
// Re-throw with Path information.
ThrowHelper.ReThrowWithPath(e, readStack.JsonPath);
}
readStack.BytesConsumed += reader.BytesConsumed;
return;
}
public static byte[] ReaderLoop(int inpuDataLength, out int length, ref Utf8JsonReader json)
{
byte[] outputArray = new byte[inpuDataLength];
Span <byte> destination = outputArray;
while (json.Read())
{
JsonTokenType tokenType = json.TokenType;
ReadOnlySpan <byte> valueSpan = json.HasValueSequence ? json.ValueSequence.ToArray() : json.ValueSpan;
if (json.HasValueSequence)
{
Assert.True(json.ValueSpan == default);
if ((tokenType != JsonTokenType.String && tokenType != JsonTokenType.PropertyName) || json.GetString().Length != 0)
{
// Empty strings could still make this true, i.e. ""
Assert.False(json.ValueSequence.IsEmpty);
}
}
else
{
Assert.True(json.ValueSequence.IsEmpty);
if ((tokenType != JsonTokenType.String && tokenType != JsonTokenType.PropertyName) || json.GetString().Length != 0)
{
// Empty strings could still make this true, i.e. ""
Assert.False(json.ValueSpan == default);
}
}
switch (tokenType)
{
case JsonTokenType.PropertyName:
valueSpan.CopyTo(destination);
destination[valueSpan.Length] = (byte)',';
destination[valueSpan.Length + 1] = (byte)' ';
destination = destination.Slice(valueSpan.Length + 2);
break;
case JsonTokenType.Number:
case JsonTokenType.String:
case JsonTokenType.Comment:
valueSpan.CopyTo(destination);
destination[valueSpan.Length] = (byte)',';
destination[valueSpan.Length + 1] = (byte)' ';
destination = destination.Slice(valueSpan.Length + 2);
break;
case JsonTokenType.True:
// Special casing True/False so that the casing matches with Json.NET
destination[0] = (byte)'T';
destination[1] = (byte)'r';
destination[2] = (byte)'u';
destination[3] = (byte)'e';
destination[valueSpan.Length] = (byte)',';
destination[valueSpan.Length + 1] = (byte)' ';
destination = destination.Slice(valueSpan.Length + 2);
break;
case JsonTokenType.False:
destination[0] = (byte)'F';
destination[1] = (byte)'a';
destination[2] = (byte)'l';
destination[3] = (byte)'s';
destination[4] = (byte)'e';
destination[valueSpan.Length] = (byte)',';
destination[valueSpan.Length + 1] = (byte)' ';
destination = destination.Slice(valueSpan.Length + 2);
break;
case JsonTokenType.Null:
// Special casing Null so that it matches what JSON.NET does
break;
case JsonTokenType.StartObject:
Assert.True(json.ValueSpan.SequenceEqual(new byte[] { (byte)'{' }));
Assert.True(json.ValueSequence.IsEmpty);
break;
case JsonTokenType.EndObject:
Assert.True(json.ValueSpan.SequenceEqual(new byte[] { (byte)'}' }));
Assert.True(json.ValueSequence.IsEmpty);
break;
case JsonTokenType.StartArray:
Assert.True(json.ValueSpan.SequenceEqual(new byte[] { (byte)'[' }));
Assert.True(json.ValueSequence.IsEmpty);
break;
case JsonTokenType.EndArray:
Assert.True(json.ValueSpan.SequenceEqual(new byte[] { (byte)']' }));
Assert.True(json.ValueSequence.IsEmpty);
break;
default:
break;
}
}
length = outputArray.Length - destination.Length;
return(outputArray);
}
public static Dictionary <string, object> ReaderDictionaryLoop(ref Utf8JsonReader json)
{
Dictionary <string, object> dictionary = new Dictionary <string, object>();
string key = "";
object value = null;
while (json.Read())
{
JsonTokenType tokenType = json.TokenType;
ReadOnlySpan <byte> valueSpan = json.ValueSpan;
switch (tokenType)
{
case JsonTokenType.PropertyName:
key = json.GetString();
dictionary.Add(key, null);
break;
case JsonTokenType.True:
case JsonTokenType.False:
value = valueSpan[0] == 't';
if (dictionary.TryGetValue(key, out _))
{
dictionary[key] = value;
}
else
{
dictionary.Add(key, value);
}
break;
case JsonTokenType.Number:
json.TryGetDouble(out double valueDouble);
if (dictionary.TryGetValue(key, out _))
{
dictionary[key] = valueDouble;
}
else
{
dictionary.Add(key, valueDouble);
}
break;
case JsonTokenType.String:
string valueString = json.GetString();
if (dictionary.TryGetValue(key, out _))
{
dictionary[key] = valueString;
}
else
{
dictionary.Add(key, valueString);
}
break;
case JsonTokenType.Null:
value = null;
if (dictionary.TryGetValue(key, out _))
{
dictionary[key] = value;
}
else
{
dictionary.Add(key, value);
}
break;
case JsonTokenType.StartObject:
Assert.True(valueSpan.SequenceEqual(new byte[] { (byte)'{' }));
value = ReaderDictionaryLoop(ref json);
if (dictionary.TryGetValue(key, out _))
{
dictionary[key] = value;
}
else
{
dictionary.Add(key, value);
}
break;
case JsonTokenType.StartArray:
Assert.True(valueSpan.SequenceEqual(new byte[] { (byte)'[' }));
value = ReaderListLoop(ref json);
if (dictionary.TryGetValue(key, out _))
{
dictionary[key] = value;
}
else
{
dictionary.Add(key, value);
}
break;
case JsonTokenType.EndObject:
Assert.True(valueSpan.SequenceEqual(new byte[] { (byte)'}' }));
return(dictionary);
case JsonTokenType.None:
case JsonTokenType.Comment:
default:
break;
}
}
return(dictionary);
}
/// <summary>
/// Parses a string representing JSON document into <see cref="JsonNode"/>.
/// </summary>
/// <param name="json">JSON to parse.</param>
/// <param name="options">Options to control the parsing behavior.</param>
/// <returns><see cref="JsonNode"/> representation of <paramref name="json"/>.</returns>
public static JsonNode Parse(string json, JsonNodeOptions options = default)
{
Utf8JsonReader reader = new Utf8JsonReader(Encoding.UTF8.GetBytes(json), options.GetReaderOptions());
var currentNodes = new Stack <KeyValuePair <string?, JsonNode?> >(); // nodes currently being created
JsonNode?toReturn = null;
while (reader.Read())
{
JsonTokenType tokenType = reader.TokenType;
currentNodes.TryPeek(out KeyValuePair <string?, JsonNode?> currentPair);
void AddNewPair(JsonNode jsonNode, bool keepInCurrentNodes = false)
{
KeyValuePair <string?, JsonNode?> newProperty;
if (currentPair.Value == null)
{
// If previous token was property name,
// it was added to stack with not null name and null value,
// otherwise, this is first JsonNode added
if (currentPair.Key != null)
{
// Create as property, keep name, replace null with new JsonNode:
currentNodes.Pop();
newProperty = new KeyValuePair <string?, JsonNode?>(currentPair.Key, jsonNode);
}
else
{
// Add first JsonNode:
newProperty = new KeyValuePair <string?, JsonNode?>(null, jsonNode);
}
}
else
{
// Create as value:
newProperty = new KeyValuePair <string?, JsonNode?>(null, jsonNode);
}
if (keepInCurrentNodes)
{
// If after adding property, it should be kept in currentNodes, it must be JsonObject or JsonArray
Debug.Assert(jsonNode.ValueKind == JsonValueKind.Object || jsonNode.ValueKind == JsonValueKind.Array);
currentNodes.Push(newProperty);
}
else
{
AddToParent(newProperty, ref currentNodes, ref toReturn, options.DuplicatePropertyNameHandling);
}
}
switch (tokenType)
{
case JsonTokenType.StartObject:
AddNewPair(new JsonObject(), true);
break;
case JsonTokenType.EndObject:
Debug.Assert(currentPair.Value is JsonObject);
currentNodes.Pop();
AddToParent(currentPair, ref currentNodes, ref toReturn, options.DuplicatePropertyNameHandling);
break;
case JsonTokenType.StartArray:
AddNewPair(new JsonArray(), true);
break;
case JsonTokenType.EndArray:
Debug.Assert(currentPair.Value is JsonArray);
currentNodes.Pop();
AddToParent(currentPair, ref currentNodes, ref toReturn, options.DuplicatePropertyNameHandling);
break;
case JsonTokenType.PropertyName:
currentNodes.Push(new KeyValuePair <string?, JsonNode?>(reader.GetString(), null));
break;
case JsonTokenType.Number:
AddNewPair(new JsonNumber(JsonHelpers.Utf8GetString(reader.ValueSpan)));
break;
case JsonTokenType.String:
AddNewPair(new JsonString(reader.GetString() !));
break;
case JsonTokenType.True:
AddNewPair(new JsonBoolean(true));
break;
case JsonTokenType.False:
AddNewPair(new JsonBoolean(false));
break;
case JsonTokenType.Null:
AddNewPair(JsonNull.Instance);
break;
}
}
Debug.Assert(toReturn != null);
return(toReturn);
}
private static Utf8JsonReader GetReaderScopedToNextValue(ref Utf8JsonReader reader, scoped ref ReadStack state)
{
// Advances the provided reader, validating that it is pointing to a complete JSON value.
// If successful, returns a new Utf8JsonReader that is scoped to the next value, reusing existing buffers.
ReadOnlySpan <byte> valueSpan = default;
ReadOnlySequence <byte> valueSequence = default;
try
{
switch (reader.TokenType)
{
// A new reader was created and has never been read,
// so we need to move to the first token.
// (or a reader has terminated and we're about to throw)
case JsonTokenType.None:
// Using a reader loop the caller has identified a property they wish to
// hydrate into a JsonDocument. Move to the value first.
case JsonTokenType.PropertyName:
{
if (!reader.Read())
{
ThrowHelper.ThrowJsonReaderException(ref reader, ExceptionResource.ExpectedOneCompleteToken);
}
break;
}
}
switch (reader.TokenType)
{
// Any of the "value start" states are acceptable.
case JsonTokenType.StartObject:
case JsonTokenType.StartArray:
long startingOffset = reader.TokenStartIndex;
if (!reader.TrySkip())
{
ThrowHelper.ThrowJsonReaderException(ref reader, ExceptionResource.NotEnoughData);
}
long totalLength = reader.BytesConsumed - startingOffset;
ReadOnlySequence <byte> sequence = reader.OriginalSequence;
if (sequence.IsEmpty)
{
valueSpan = reader.OriginalSpan.Slice(
checked ((int)startingOffset),
checked ((int)totalLength));
}
else
{
valueSequence = sequence.Slice(startingOffset, totalLength);
}
Debug.Assert(reader.TokenType is JsonTokenType.EndObject or JsonTokenType.EndArray);
break;
// Single-token values
case JsonTokenType.Number:
case JsonTokenType.True:
case JsonTokenType.False:
case JsonTokenType.Null:
if (reader.HasValueSequence)
{
valueSequence = reader.ValueSequence;
}
else
{
valueSpan = reader.ValueSpan;
}
break;
// String's ValueSequence/ValueSpan omits the quotes, we need them back.
case JsonTokenType.String:
ReadOnlySequence <byte> originalSequence = reader.OriginalSequence;
if (originalSequence.IsEmpty)
{
// Since the quoted string fit in a ReadOnlySpan originally
// the contents length plus the two quotes can't overflow.
int payloadLength = reader.ValueSpan.Length + 2;
Debug.Assert(payloadLength > 1);
ReadOnlySpan <byte> readerSpan = reader.OriginalSpan;
Debug.Assert(
readerSpan[(int)reader.TokenStartIndex] == (byte)'"',
$"Calculated span starts with {readerSpan[(int)reader.TokenStartIndex]}");
Debug.Assert(
readerSpan[(int)reader.TokenStartIndex + payloadLength - 1] == (byte)'"',
$"Calculated span ends with {readerSpan[(int)reader.TokenStartIndex + payloadLength - 1]}");
valueSpan = readerSpan.Slice((int)reader.TokenStartIndex, payloadLength);
}
else
{
long payloadLength = reader.HasValueSequence
? reader.ValueSequence.Length + 2
: reader.ValueSpan.Length + 2;
valueSequence = originalSequence.Slice(reader.TokenStartIndex, payloadLength);
Debug.Assert(
valueSequence.First.Span[0] == (byte)'"',
$"Calculated sequence starts with {valueSequence.First.Span[0]}");
Debug.Assert(
valueSequence.ToArray()[payloadLength - 1] == (byte)'"',
$"Calculated sequence ends with {valueSequence.ToArray()[payloadLength - 1]}");
}
break;
default:
byte displayByte = reader.HasValueSequence
? reader.ValueSequence.First.Span[0]
: reader.ValueSpan[0];
ThrowHelper.ThrowJsonReaderException(
ref reader,
ExceptionResource.ExpectedStartOfValueNotFound,
displayByte);
break;
}
}
catch (JsonReaderException ex)
{
// Re-throw with Path information.
ThrowHelper.ReThrowWithPath(ref state, ex);
}
Debug.Assert(!valueSpan.IsEmpty ^ !valueSequence.IsEmpty);
return(valueSpan.IsEmpty
? new Utf8JsonReader(valueSequence, reader.CurrentState.Options)
: new Utf8JsonReader(valueSpan, reader.CurrentState.Options));
}
private static void ReadCore(
JsonSerializerOptions options,
ref Utf8JsonReader reader,
ref ReadStack state)
{
try
{
JsonPropertyInfo jsonPropertyInfo = state.Current.JsonClassInfo !.PolicyProperty !;
JsonConverter converter = jsonPropertyInfo.ConverterBase;
if (!state.IsContinuation)
{
if (!JsonConverter.SingleValueReadWithReadAhead(converter.ClassType, ref reader, ref state))
{
// Read more data until we have the full element.
state.BytesConsumed += reader.BytesConsumed;
return;
}
}
else
{
// For a continuation, read ahead here to avoid having to build and then tear
// down the call stack if there is more than one buffer fetch necessary.
if (!JsonConverter.SingleValueReadWithReadAhead(ClassType.Value, ref reader, ref state))
{
state.BytesConsumed += reader.BytesConsumed;
return;
}
}
bool success = converter.TryReadAsObject(ref reader, jsonPropertyInfo.RuntimePropertyType !, options, ref state, out object?value);
if (success)
{
state.Current.ReturnValue = value;
// Read any trailing whitespace.
// If additional whitespace exists after this read, the subsequent call to reader.Read() will throw.
reader.Read();
}
state.BytesConsumed += reader.BytesConsumed;
}
catch (JsonReaderException ex)
{
// Re-throw with Path information.
ThrowHelper.ReThrowWithPath(state, ex);
}
catch (FormatException ex) when(ex.Source == ThrowHelper.ExceptionSourceValueToRethrowAsJsonException)
{
ThrowHelper.ReThrowWithPath(state, reader, ex);
}
catch (InvalidOperationException ex) when(ex.Source == ThrowHelper.ExceptionSourceValueToRethrowAsJsonException)
{
ThrowHelper.ReThrowWithPath(state, reader, ex);
}
catch (JsonException ex)
{
ThrowHelper.AddExceptionInformation(state, reader, ex);
throw;
}
}
private static void ReadCore(
JsonSerializerOptions options,
ref Utf8JsonReader reader,
ref ReadStack readStack)
{
try
{
JsonReaderState initialState = default;
long initialBytesConsumed = default;
while (true)
{
if (readStack.ReadAhead)
{
// When we're reading ahead we always have to save the state
// as we don't know if the next token is an opening object or
// array brace.
initialState = reader.CurrentState;
initialBytesConsumed = reader.BytesConsumed;
}
if (!reader.Read())
{
// Need more data
break;
}
JsonTokenType tokenType = reader.TokenType;
if (JsonHelpers.IsInRangeInclusive(tokenType, JsonTokenType.String, JsonTokenType.False))
{
Debug.Assert(tokenType == JsonTokenType.String || tokenType == JsonTokenType.Number || tokenType == JsonTokenType.True || tokenType == JsonTokenType.False);
HandleValue(tokenType, options, ref reader, ref readStack);
}
else if (tokenType == JsonTokenType.PropertyName)
{
HandlePropertyName(options, ref reader, ref readStack);
}
else if (tokenType == JsonTokenType.StartObject)
{
if (readStack.Current.SkipProperty)
{
readStack.Push();
readStack.Current.Drain = true;
}
else if (readStack.Current.IsProcessingValue())
{
if (!HandleObjectAsValue(tokenType, options, ref reader, ref readStack, ref initialState, initialBytesConsumed))
{
// Need more data
break;
}
}
else if (readStack.Current.IsProcessingDictionary || readStack.Current.IsProcessingIDictionaryConstructible)
{
HandleStartDictionary(options, ref reader, ref readStack);
}
else
{
HandleStartObject(options, ref readStack);
}
}
else if (tokenType == JsonTokenType.EndObject)
{
if (readStack.Current.Drain)
{
readStack.Pop();
// Clear the current property in case it is a dictionary, since dictionaries must have EndProperty() called when completed.
// A non-dictionary property can also have EndProperty() called when completed, although it is redundant.
readStack.Current.EndProperty();
}
else if (readStack.Current.IsProcessingDictionary || readStack.Current.IsProcessingIDictionaryConstructible)
{
HandleEndDictionary(options, ref reader, ref readStack);
}
else
{
HandleEndObject(ref reader, ref readStack);
}
}
else if (tokenType == JsonTokenType.StartArray)
{
if (!readStack.Current.IsProcessingValue())
{
HandleStartArray(options, ref reader, ref readStack);
}
else if (!HandleObjectAsValue(tokenType, options, ref reader, ref readStack, ref initialState, initialBytesConsumed))
{
// Need more data
break;
}
}
else if (tokenType == JsonTokenType.EndArray)
{
HandleEndArray(options, ref reader, ref readStack);
}
else if (tokenType == JsonTokenType.Null)
{
HandleNull(ref reader, ref readStack);
}
}
}
catch (JsonReaderException ex)
{
// Re-throw with Path information.
ThrowHelper.ReThrowWithPath(readStack, ex);
}
catch (FormatException ex) when(ex.Source == ThrowHelper.ExceptionSourceValueToRethrowAsJsonException)
{
ThrowHelper.ReThrowWithPath(readStack, reader, ex);
}
catch (InvalidOperationException ex) when(ex.Source == ThrowHelper.ExceptionSourceValueToRethrowAsJsonException)
{
ThrowHelper.ReThrowWithPath(readStack, reader, ex);
}
catch (JsonException ex)
{
ThrowHelper.AddExceptionInformation(readStack, reader, ex);
throw;
}
readStack.BytesConsumed += reader.BytesConsumed;
return;
}
internal static bool TryReadMetadata(JsonConverter converter, JsonTypeInfo jsonTypeInfo, ref Utf8JsonReader reader, scoped ref ReadStack state)
{
Debug.Assert(state.Current.ObjectState == StackFrameObjectState.StartToken);
Debug.Assert(state.Current.CanContainMetadata);
while (true)
{
if (state.Current.PropertyState == StackFramePropertyState.None)
{
state.Current.PropertyState = StackFramePropertyState.ReadName;
// Read the property name.
if (!reader.Read())
{
return(false);
}
}
if (state.Current.PropertyState < StackFramePropertyState.Name)
{
if (reader.TokenType == JsonTokenType.EndObject)
{
// Read the entire object while parsing for metadata.
return(true);
}
// We just read a property. The only valid next tokens are EndObject and PropertyName.
Debug.Assert(reader.TokenType == JsonTokenType.PropertyName);
if (state.Current.MetadataPropertyNames.HasFlag(MetadataPropertyName.Ref))
{
// No properties whatsoever should follow a $ref property.
ThrowHelper.ThrowJsonException_MetadataReferenceObjectCannotContainOtherProperties(reader.GetSpan(), ref state);
}
ReadOnlySpan <byte> propertyName = reader.GetSpan();
switch (state.Current.LatestMetadataPropertyName = GetMetadataPropertyName(propertyName, jsonTypeInfo.PolymorphicTypeResolver))
{
case MetadataPropertyName.Id:
state.Current.JsonPropertyName = s_idPropertyName;
if (state.ReferenceResolver is null)
{
// Found an $id property in a type that doesn't support reference preservation
ThrowHelper.ThrowJsonException_MetadataUnexpectedProperty(propertyName, ref state);
}
if ((state.Current.MetadataPropertyNames & (MetadataPropertyName.Id | MetadataPropertyName.Ref)) != 0)
{
// No $id or $ref properties should precede $id properties.
ThrowHelper.ThrowJsonException_MetadataIdIsNotFirstProperty(propertyName, ref state);
}
if (!converter.CanHaveMetadata)
{
// Should not be permitted unless the converter is capable of handling metadata.
ThrowHelper.ThrowJsonException_MetadataCannotParsePreservedObjectIntoImmutable(converter.TypeToConvert);
}
break;
case MetadataPropertyName.Ref:
state.Current.JsonPropertyName = s_refPropertyName;
if (state.ReferenceResolver is null)
{
// Found a $ref property in a type that doesn't support reference preservation
ThrowHelper.ThrowJsonException_MetadataUnexpectedProperty(propertyName, ref state);
}
if (converter.IsValueType)
{
// Should not be permitted if the converter is a struct.
ThrowHelper.ThrowJsonException_MetadataInvalidReferenceToValueType(converter.TypeToConvert);
}
if (state.Current.MetadataPropertyNames != 0)
{
// No metadata properties should precede a $ref property.
ThrowHelper.ThrowJsonException_MetadataReferenceObjectCannotContainOtherProperties(reader.GetSpan(), ref state);
}
break;
case MetadataPropertyName.Type:
state.Current.JsonPropertyName = jsonTypeInfo.PolymorphicTypeResolver?.TypeDiscriminatorPropertyNameUtf8 ?? s_typePropertyName;
if (jsonTypeInfo.PolymorphicTypeResolver is null)
{
// Found a $type property in a type that doesn't support polymorphism
ThrowHelper.ThrowJsonException_MetadataUnexpectedProperty(propertyName, ref state);
}
if (state.PolymorphicTypeDiscriminator != null)
{
ThrowHelper.ThrowJsonException_MetadataDuplicateTypeProperty();
}
break;
case MetadataPropertyName.Values:
state.Current.JsonPropertyName = s_valuesPropertyName;
if (state.Current.MetadataPropertyNames == MetadataPropertyName.None)
{
// Cannot have a $values property unless there are preceding metadata properties.
ThrowHelper.ThrowJsonException_MetadataStandaloneValuesProperty(ref state, propertyName);
}
break;
default:
Debug.Assert(state.Current.LatestMetadataPropertyName == MetadataPropertyName.None);
// Encountered a non-metadata property, exit the reader.
return(true);
}
state.Current.PropertyState = StackFramePropertyState.Name;
}
if (state.Current.PropertyState < StackFramePropertyState.ReadValue)
{
state.Current.PropertyState = StackFramePropertyState.ReadValue;
// Read the property value.
if (!reader.Read())
{
return(false);
}
}
Debug.Assert(state.Current.PropertyState == StackFramePropertyState.ReadValue);
switch (state.Current.LatestMetadataPropertyName)
{
case MetadataPropertyName.Id:
if (reader.TokenType != JsonTokenType.String)
{
ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
}
if (state.ReferenceId != null)
{
ThrowHelper.ThrowNotSupportedException_ObjectWithParameterizedCtorRefMetadataNotSupported(s_refPropertyName, ref reader, ref state);
}
state.ReferenceId = reader.GetString();
break;
case MetadataPropertyName.Ref:
if (reader.TokenType != JsonTokenType.String)
{
ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
}
if (state.ReferenceId != null)
{
ThrowHelper.ThrowNotSupportedException_ObjectWithParameterizedCtorRefMetadataNotSupported(s_refPropertyName, ref reader, ref state);
}
state.ReferenceId = reader.GetString();
break;
case MetadataPropertyName.Type:
Debug.Assert(state.PolymorphicTypeDiscriminator == null);
switch (reader.TokenType)
{
case JsonTokenType.String:
state.PolymorphicTypeDiscriminator = reader.GetString();
break;
case JsonTokenType.Number:
state.PolymorphicTypeDiscriminator = reader.GetInt32();
break;
default:
ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
break;
}
break;
case MetadataPropertyName.Values:
if (reader.TokenType != JsonTokenType.StartArray)
{
ThrowHelper.ThrowJsonException_MetadataValuesInvalidToken(reader.TokenType);
}
state.Current.PropertyState = StackFramePropertyState.None;
state.Current.MetadataPropertyNames |= state.Current.LatestMetadataPropertyName;
return(true); // "$values" property contains the nested payload, exit the metadata reader now.
default:
Debug.Fail("Non-metadata properties should not reach this stage.");
break;
}
state.Current.MetadataPropertyNames |= state.Current.LatestMetadataPropertyName;
state.Current.PropertyState = StackFramePropertyState.None;
state.Current.JsonPropertyName = null;
}
}
