private static bool HandleObjectAsValue(
JsonTokenType tokenType,
JsonSerializerOptions options,
ref Utf8JsonReader reader,
ref ReadStack readStack,
ref JsonReaderState initialState,
long initialBytesConsumed)
{
if (readStack.ReadAhead)
{
// Attempt to skip to make sure we have all the data we need.
bool complete = reader.TrySkip();
// We need to restore the state in all cases as we need to be positioned back before
// the current token to either attempt to skip again or to actually read the value in
// HandleValue below.
reader = new Utf8JsonReader(
reader.OriginalSpan.Slice(checked ((int)initialBytesConsumed)),
isFinalBlock: reader.IsFinalBlock,
state: initialState);
Debug.Assert(reader.BytesConsumed == 0);
readStack.BytesConsumed += initialBytesConsumed;
if (!complete)
{
// Couldn't read to the end of the object, exit out to get more data in the buffer.
return(false);
}
// Success, requeue the reader to the token for HandleValue.
reader.Read();
Debug.Assert(tokenType == reader.TokenType);
}
HandleValue(tokenType, options, ref reader, ref readStack);
return(true);
}
internal static bool TryParseValue(
ref Utf8JsonReader reader,
[NotNullWhen(true)] out JsonDocument?document,
bool shouldThrow,
bool useArrayPools)
{
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;
if (!reader.TrySkip())
{
if (shouldThrow)
{
ThrowHelper.ThrowJsonReaderException(
ref reader,
ExceptionResource.ExpectedJsonTokens);
}
reader = restore;
document = null;
return(false);
}
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;
}
case JsonTokenType.False:
case JsonTokenType.True:
case JsonTokenType.Null:
if (useArrayPools)
{
if (reader.HasValueSequence)
{
valueSequence = reader.ValueSequence;
}
else
{
valueSpan = reader.ValueSpan;
}
break;
}
document = CreateForLiteral(reader.TokenType);
return(true);
case JsonTokenType.Number:
{
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)
{
// Default case would only hit if TokenType equals JsonTokenType.EndObject or JsonTokenType.EndArray in which case it would never be sequence
Debug.Assert(!reader.HasValueSequence);
byte 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;
if (useArrayPools)
{
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);
}
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;
}
}
else
{
byte[] owned;
if (valueSpan.IsEmpty)
{
owned = valueSequence.ToArray();
}
else
{
owned = valueSpan.ToArray();
}
document = ParseUnrented(owned, state.Options, reader.TokenType);
}
return(true);
}
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);
// The reader should have thrown if we have remaining bytes.
Debug.Assert(newReader.BytesConsumed == length);
}
catch (JsonException)
{
reader = restore;
throw;
}
finally
{
rentedSpan.Clear();
ArrayPool <byte> .Shared.Return(rented);
}
}
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));
}
