public static byte[] SequenceReturnBytesHelper(byte[] data, out int length, JsonCommentHandling commentHandling = JsonCommentHandling.Disallow, int maxDepth = 64)
{
ReadOnlySequence <byte> sequence = CreateSegments(data);
var state = new JsonReaderState(new JsonReaderOptions {
CommentHandling = commentHandling, MaxDepth = maxDepth
});
var reader = new Utf8JsonReader(sequence, true, state);
return(ReaderLoop(data.Length, out length, ref reader));
}
/// <summary>
/// Parse the text representing a single JSON value into a <paramref name="returnType"/>.
/// </summary>
/// <returns>A <paramref name="returnType"/> representation of the JSON value.</returns>
/// <param name="json">JSON text to parse.</param>
/// <param name="returnType">The type of the object to convert to and return.</param>
/// <param name="options">Options to control the behavior during parsing.</param>
/// <exception cref="System.ArgumentNullException">
/// Thrown if <paramref name="json"/> or <paramref name="returnType"/> is null.
/// </exception>
/// <exception cref="JsonException">
/// Thrown when the JSON is invalid,
/// the <paramref name="returnType"/> is not compatible with the JSON,
/// or when there is remaining data in the Stream.
/// </exception>
/// <remarks>Using a <see cref="System.String"/> is not as efficient as using the
/// UTF-8 methods since the implementation natively uses UTF-8.
/// </remarks>
public static object Deserialize(string json, Type returnType, JsonSerializerOptions options = null)
{
const long ArrayPoolMaxSizeBeforeUsingNormalAlloc = 1024 * 1024;
if (json == null)
{
throw new ArgumentNullException(nameof(json));
}
if (returnType == null)
{
throw new ArgumentNullException(nameof(returnType));
}
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
object result;
byte[] tempArray = null;
// For performance, avoid obtaining actual byte count unless memory usage is higher than the threshold.
Span <byte> utf8 = json.Length <= (ArrayPoolMaxSizeBeforeUsingNormalAlloc / JsonConstants.MaxExpansionFactorWhileTranscoding) ?
// Use a pooled alloc.
tempArray = ArrayPool <byte> .Shared.Rent(json.Length *JsonConstants.MaxExpansionFactorWhileTranscoding) :
// Use a normal alloc since the pool would create a normal alloc anyway based on the threshold (per current implementation)
// and by using a normal alloc we can avoid the Clear().
new byte[JsonReaderHelper.GetUtf8ByteCount(json.AsSpan())];
try
{
int actualByteCount = JsonReaderHelper.GetUtf8FromText(json.AsSpan(), utf8);
utf8 = utf8.Slice(0, actualByteCount);
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8, isFinalBlock: true, readerState);
result = ReadCore(returnType, options, ref reader);
// The reader should have thrown if we have remaining bytes.
Debug.Assert(reader.BytesConsumed == actualByteCount);
}
finally
{
if (tempArray != null)
{
utf8.Clear();
ArrayPool <byte> .Shared.Return(tempArray);
}
}
return(result);
}
/// <summary>
/// Parse the UTF-8 encoded text representing a single JSON value into a <typeparamref name="TValue"/>.
/// </summary>
/// <returns>A <typeparamref name="TValue"/> representation of the JSON value.</returns>
/// <param name="utf8Json">JSON text to parse.</param>
/// <param name="options">Options to control the behavior during parsing.</param>
/// <exception cref="JsonException">
/// Thrown when the JSON is invalid,
/// <typeparamref name="TValue"/> is not compatible with the JSON,
/// or when there is remaining data in the Stream.
/// </exception>
/// <exception cref="NotSupportedException">
/// There is no compatible <see cref="System.Text.Json.Serialization.JsonConverter"/>
/// for <typeparamref name="TValue"/> or its serializable members.
/// </exception>
public static TValue?Deserialize <[DynamicallyAccessedMembers(JsonHelpers.MembersAccessedOnRead)] TValue>(ReadOnlySpan <byte> utf8Json, JsonSerializerOptions?options = null)
{
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
return(ReadCore <TValue>(ref reader, typeof(TValue), options));
}
public static TValue Deserialize <TValue>(ReadOnlySpan <byte> utf8Json, JsonSerializerOptions?options = null)
{
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
return(ReadCore <TValue>(ref reader, typeof(TValue), options));
}
private static async IAsyncEnumerable <TValue> CreateAsyncEnumerableDeserializer <TValue>(
Stream utf8Json,
JsonTypeInfo jsonTypeInfo,
[EnumeratorCancellation] CancellationToken cancellationToken)
{
JsonSerializerOptions options = jsonTypeInfo.Options;
JsonTypeInfo <Queue <TValue> > queueTypeInfo =
JsonMetadataServices.CreateQueueInfo <Queue <TValue>, TValue>(
options: options,
collectionInfo: new()
{
ObjectCreator = () => new Queue <TValue>(),
ElementInfo = jsonTypeInfo,
NumberHandling = options.NumberHandling
});
var bufferState = new ReadBufferState(options.DefaultBufferSize);
ReadStack readStack = default;
queueTypeInfo.EnsureConfigured();
readStack.Initialize(queueTypeInfo, supportContinuation: true);
var jsonReaderState = new JsonReaderState(options.GetReaderOptions());
try
{
do
{
bufferState = await ReadFromStreamAsync(utf8Json, bufferState, cancellationToken).ConfigureAwait(false);
ContinueDeserialize <Queue <TValue> >(
ref bufferState,
ref jsonReaderState,
ref readStack,
queueTypeInfo.PropertyInfoForTypeInfo.ConverterBase,
options);
if (readStack.Current.ReturnValue is Queue <TValue> queue)
{
while (queue.Count > 0)
{
yield return(queue.Dequeue());
}
}
}while (!bufferState.IsFinalBlock);
}
finally
{
bufferState.Dispose();
}
}
private static object?ParseCore(ReadOnlySpan <byte> utf8Json, Type returnType, JsonSerializerOptions?options)
{
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
object?result = ReadCore(returnType, options, ref reader);
// The reader should have thrown if we have remaining bytes.
Debug.Assert(reader.BytesConsumed == utf8Json.Length);
return(result);
}
/// <summary>
/// Parse the UTF-8 encoded text representing a single JSON value into a <paramref name="returnType"/>.
/// </summary>
/// <returns>A <paramref name="returnType"/> representation of the JSON value.</returns>
/// <param name="utf8Json">JSON text to parse.</param>
/// <param name="returnType">The type of the object to convert to and return.</param>
/// <param name="options">Options to control the behavior during parsing.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="returnType"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="JsonException">
/// Thrown when the JSON is invalid,
/// <paramref name="returnType"/> is not compatible with the JSON,
/// or when there is remaining data in the Stream.
/// </exception>
/// <exception cref="NotSupportedException">
/// There is no compatible <see cref="System.Text.Json.Serialization.JsonConverter"/>
/// for <paramref name="returnType"/> or its serializable members.
/// </exception>
public static object?Deserialize(ReadOnlySpan <byte> utf8Json, Type returnType, JsonSerializerOptions?options = null)
{
if (returnType == null)
{
throw new ArgumentNullException(nameof(returnType));
}
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
return(ReadCore <object>(ref reader, returnType, options));
}
private static TValue?ReadUsingMetadata <TValue>(ReadOnlySpan <byte> utf8Json, JsonTypeInfo jsonTypeInfo, int?actualByteCount = null)
{
JsonSerializerOptions options = jsonTypeInfo.Options;
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
ReadStack state = default;
state.Initialize(jsonTypeInfo);
TValue?value = ReadCore <TValue>(jsonTypeInfo.PropertyInfoForTypeInfo.ConverterBase, ref reader, options, ref state);
// The reader should have thrown if we have remaining bytes.
Debug.Assert(reader.BytesConsumed == (actualByteCount ?? utf8Json.Length));
return(value);
}
/// <summary>
/// Parse the UTF-8 encoded text representing a single JSON value into a <typeparamref name="TValue"/>.
/// </summary>
/// <returns>A <typeparamref name="TValue"/> representation of the JSON value.</returns>
/// <param name="utf8Json">JSON text to parse.</param>
/// <param name="jsonTypeInfo">Metadata about the type to convert.</param>
/// <exception cref="JsonException">
/// Thrown when the JSON is invalid,
/// <typeparamref name="TValue"/> is not compatible with the JSON,
/// or when there is remaining data in the Stream.
/// </exception>
/// <exception cref="NotSupportedException">
/// There is no compatible <see cref="System.Text.Json.Serialization.JsonConverter"/>
/// for <typeparamref name="TValue"/> or its serializable members.
/// </exception>
public static TValue?Deserialize <TValue>(ReadOnlySpan <byte> utf8Json, JsonTypeInfo <TValue> jsonTypeInfo)
{
if (jsonTypeInfo == null)
{
throw new ArgumentNullException(nameof(jsonTypeInfo));
}
JsonSerializerOptions options = jsonTypeInfo.Options;
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
ReadStack state = default;
state.Initialize(jsonTypeInfo);
return(ReadCore <TValue>(jsonTypeInfo.PropertyInfoForTypeInfo.ConverterBase, ref reader, options, ref state));
}
/// <summary>
/// Parse the UTF-8 encoded text representing a single JSON value into a <paramref name="returnType"/>.
/// </summary>
/// <returns>A <paramref name="returnType"/> representation of the JSON value.</returns>
/// <param name="utf8Json">JSON text to parse.</param>
/// <param name="returnType">The type of the object to convert to and return.</param>
/// <param name="options">Options to control the behavior during parsing.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="returnType"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="JsonException">
/// Thrown when the JSON is invalid,
/// <paramref name="returnType"/> is not compatible with the JSON,
/// or when there is remaining data in the Stream.
/// </exception>
/// <exception cref="NotSupportedException">
/// There is no compatible <see cref="System.Text.Json.Serialization.JsonConverter"/>
/// for <paramref name="returnType"/> or its serializable members.
/// </exception>
public static object?Deserialize(ReadOnlySpan <byte> utf8Json, [DynamicallyAccessedMembers(JsonHelpers.MembersAccessedOnRead)] Type returnType, JsonSerializerOptions?options = null)
{
if (returnType == null)
{
throw new ArgumentNullException(nameof(returnType));
}
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
options.RootBuiltInConvertersAndTypeInfoCreator();
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
return(ReadCore <object>(ref reader, returnType, options));
}
private static TValue?Deserialize <TValue>(
JsonConverter jsonConverter,
ReadOnlySpan <char> json,
JsonSerializerOptions options,
ref ReadStack state)
{
const long ArrayPoolMaxSizeBeforeUsingNormalAlloc = 1024 * 1024;
byte[]? tempArray = null;
// For performance, avoid obtaining actual byte count unless memory usage is higher than the threshold.
Span <byte> utf8 = json.Length <= (ArrayPoolMaxSizeBeforeUsingNormalAlloc / JsonConstants.MaxExpansionFactorWhileTranscoding) ?
// Use a pooled alloc.
tempArray = ArrayPool <byte> .Shared.Rent(json.Length *JsonConstants.MaxExpansionFactorWhileTranscoding) :
// Use a normal alloc since the pool would create a normal alloc anyway based on the threshold (per current implementation)
// and by using a normal alloc we can avoid the Clear().
new byte[JsonReaderHelper.GetUtf8ByteCount(json)];
try
{
int actualByteCount = JsonReaderHelper.GetUtf8FromText(json, utf8);
utf8 = utf8.Slice(0, actualByteCount);
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8, isFinalBlock: true, readerState);
TValue?value = ReadCore <TValue>(jsonConverter, ref reader, options, ref state);
// The reader should have thrown if we have remaining bytes.
Debug.Assert(reader.BytesConsumed == actualByteCount);
return(value);
}
finally
{
if (tempArray != null)
{
utf8.Clear();
ArrayPool <byte> .Shared.Return(tempArray);
}
}
}
private static TValue ReadCore <TValue>(
ref JsonReaderState readerState,
bool isFinalBlock,
ReadOnlySpan <byte> buffer,
JsonSerializerOptions options,
ref ReadStack state,
JsonConverter converterBase)
{
var reader = new Utf8JsonReader(buffer, isFinalBlock, readerState);
// If we haven't read in the entire stream's payload we'll need to signify that we want
// to enable read ahead behaviors to ensure we have complete json objects and arrays
// ({}, []) when needed. (Notably to successfully parse JsonElement via JsonDocument
// to assign to object and JsonElement properties in the constructed .NET object.)
state.ReadAhead = !isFinalBlock;
state.BytesConsumed = 0;
TValue?value = ReadCore <TValue>(converterBase, ref reader, options, ref state);
readerState = reader.CurrentState;
return(value !);
}
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);
}
private static void ReadCore(
ref JsonReaderState readerState,
bool isFinalBlock,
Span <byte> buffer,
JsonSerializerOptions options,
ref ReadStack readStack)
{
var reader = new Utf8JsonReader(buffer, isFinalBlock, readerState);
// If we haven't read in the entire stream's payload we'll need to signify that we want
// to enable read ahead behaviors to ensure we have complete json objects and arrays
// ({}, []) when needed. (Notably to successfully parse JsonElement via JsonDocument
// to assign to object and JsonElement properties in the constructed .NET object.)
readStack.ReadAhead = !isFinalBlock;
readStack.BytesConsumed = 0;
ReadCore(
options,
ref reader,
ref readStack);
readerState = reader.CurrentState;
}
static async IAsyncEnumerable <TValue> CreateAsyncEnumerableDeserializer(
Stream utf8Json,
JsonSerializerOptions options,
[EnumeratorCancellation] CancellationToken cancellationToken)
{
var bufferState = new ReadBufferState(options.DefaultBufferSize);
// Hardcode the queue converter to avoid accidental use of custom converters
JsonConverter converter = QueueOfTConverter <Queue <TValue>, TValue> .Instance;
JsonTypeInfo jsonTypeInfo = CreateQueueJsonTypeInfo <TValue>(converter, options);
ReadStack readStack = default;
jsonTypeInfo.EnsureConfigured();
readStack.Initialize(jsonTypeInfo, supportContinuation: true);
var jsonReaderState = new JsonReaderState(options.GetReaderOptions());
try
{
do
{
bufferState = await ReadFromStreamAsync(utf8Json, bufferState, cancellationToken).ConfigureAwait(false);
ContinueDeserialize <Queue <TValue> >(ref bufferState, ref jsonReaderState, ref readStack, converter, options);
if (readStack.Current.ReturnValue is Queue <TValue> queue)
{
while (queue.Count > 0)
{
yield return(queue.Dequeue());
}
}
}while (!bufferState.IsFinalBlock);
}
finally
{
bufferState.Dispose();
}
}
/// <summary>
/// Parse the UTF-8 encoded text representing a single JSON value into a <paramref name="returnType"/>.
/// </summary>
/// <returns>A <paramref name="returnType"/> representation of the JSON value.</returns>
/// <param name="utf8Json">JSON text to parse.</param>
/// <param name="returnType">The type of the object to convert to and return.</param>
/// <param name="context">A metadata provider for serializable types.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="returnType"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="JsonException">
/// Thrown when the JSON is invalid,
/// <paramref name="returnType"/> is not compatible with the JSON,
/// or when there is remaining data in the Stream.
/// </exception>
/// <exception cref="NotSupportedException">
/// There is no compatible <see cref="System.Text.Json.Serialization.JsonConverter"/>
/// for <paramref name="returnType"/> or its serializable members.
/// </exception>
/// <exception cref="InvalidOperationException">
/// The <see cref="JsonSerializerContext.GetTypeInfo(Type)"/> method on the provided <paramref name="context"/>
/// did not return a compatible <see cref="JsonTypeInfo"/> for <paramref name="returnType"/>.
/// </exception>
public static object?Deserialize(ReadOnlySpan <byte> utf8Json, Type returnType, JsonSerializerContext context)
{
if (returnType == null)
{
throw new ArgumentNullException(nameof(returnType));
}
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
JsonTypeInfo jsonTypeInfo = JsonHelpers.GetTypeInfo(context, returnType);
JsonSerializerOptions options = jsonTypeInfo.Options;
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8Json, isFinalBlock: true, readerState);
ReadStack state = default;
state.Initialize(jsonTypeInfo);
return(ReadCore <object?>(jsonTypeInfo.PropertyInfoForTypeInfo.ConverterBase, ref reader, options, ref state));
}
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 (options.ReferenceHandling.ShouldReadPreservedReferences())
{
CheckValidTokenAfterMetadataValues(ref readStack, 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())
{
HandleStartDictionary(options, 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.ReferenceId != null)
{
Debug.Assert(options.ReferenceHandling.ShouldReadPreservedReferences());
HandleReference(ref readStack);
}
else if (readStack.Current.IsProcessingDictionary())
{
HandleEndDictionary(options, ref readStack);
}
else
{
HandleEndObject(ref readStack);
}
}
else if (tokenType == JsonTokenType.StartArray)
{
if (!readStack.Current.IsProcessingValue())
{
HandleStartArray(options, 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 readStack);
}
else if (tokenType == JsonTokenType.Null)
{
HandleNull(options, 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;
}
private static async ValueTask <TValue> ReadAsync <TValue>(
Stream utf8Json,
Type returnType,
JsonSerializerOptions options = null,
CancellationToken cancellationToken = default)
{
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
ReadStack readStack = default;
readStack.Current.Initialize(returnType, options);
var readerState = new JsonReaderState(options.GetReaderOptions());
// todo: switch to ArrayBuffer implementation to handle and simplify the allocs?
int utf8BomLength = JsonConstants.Utf8Bom.Length;
byte[] buffer = ArrayPool <byte> .Shared.Rent(Math.Max(options.DefaultBufferSize, utf8BomLength));
int bytesInBuffer = 0;
long totalBytesRead = 0;
int clearMax = 0;
bool firstIteration = true;
try
{
while (true)
{
// Read from the stream until either our buffer is filled or we hit EOF.
// Calling ReadCore is relatively expensive, so we minimize the number of times
// we need to call it.
bool isFinalBlock = false;
while (true)
{
int bytesRead = await utf8Json.ReadAsync(
#if BUILDING_INBOX_LIBRARY
buffer.AsMemory(bytesInBuffer),
#else
buffer, bytesInBuffer, buffer.Length - bytesInBuffer,
#endif
cancellationToken).ConfigureAwait(false);
if (bytesRead == 0)
{
isFinalBlock = true;
break;
}
totalBytesRead += bytesRead;
bytesInBuffer += bytesRead;
if (bytesInBuffer == buffer.Length)
{
break;
}
}
if (bytesInBuffer > clearMax)
{
clearMax = bytesInBuffer;
}
int start = 0;
if (firstIteration)
{
firstIteration = false;
// Handle the UTF-8 BOM if present
Debug.Assert(buffer.Length >= JsonConstants.Utf8Bom.Length);
if (buffer.AsSpan().StartsWith(JsonConstants.Utf8Bom))
{
start += utf8BomLength;
bytesInBuffer -= utf8BomLength;
}
}
// Process the data available
ReadCore(
ref readerState,
isFinalBlock,
new ReadOnlySpan <byte>(buffer, start, bytesInBuffer),
options,
ref readStack);
Debug.Assert(readStack.BytesConsumed <= bytesInBuffer);
int bytesConsumed = checked ((int)readStack.BytesConsumed);
bytesInBuffer -= bytesConsumed;
if (isFinalBlock)
{
break;
}
// Check if we need to shift or expand the buffer because there wasn't enough data to complete deserialization.
if ((uint)bytesInBuffer > ((uint)buffer.Length / 2))
{
// We have less than half the buffer available, double the buffer size.
byte[] dest = ArrayPool <byte> .Shared.Rent((buffer.Length < (int.MaxValue / 2))?buffer.Length * 2 : int.MaxValue);
// Copy the unprocessed data to the new buffer while shifting the processed bytes.
Buffer.BlockCopy(buffer, bytesConsumed + start, dest, 0, bytesInBuffer);
new Span <byte>(buffer, 0, clearMax).Clear();
ArrayPool <byte> .Shared.Return(buffer);
clearMax = bytesInBuffer;
buffer = dest;
}
else if (bytesInBuffer != 0)
{
// Shift the processed bytes to the beginning of buffer to make more room.
Buffer.BlockCopy(buffer, bytesConsumed + start, buffer, 0, bytesInBuffer);
}
}
}
finally
{
// Clear only what we used and return the buffer to the pool
new Span <byte>(buffer, 0, clearMax).Clear();
ArrayPool <byte> .Shared.Return(buffer);
}
// The reader should have thrown if we have remaining bytes.
Debug.Assert(bytesInBuffer == 0);
return((TValue)readStack.Current.ReturnValue);
}
public static byte[] ReturnBytesHelper(byte[] data, out int length, JsonCommentHandling commentHandling = JsonCommentHandling.Disallow, int maxDepth = 64)
{
var state = new JsonReaderState(new JsonReaderOptions { CommentHandling = commentHandling, MaxDepth = maxDepth });
var reader = new Utf8JsonReader(data, true, state);
return ReaderLoop(data.Length, out length, ref reader);
}
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;
// Only used for StartArray or StartObject,
// the beginning of the token is one byte earlier.
long startingOffset = state.BytesConsumed;
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);
}
// Reset the starting position since we moved.
startingOffset = reader.BytesConsumed;
break;
}
}
switch (reader.TokenType)
{
// Any of the "value start" states are acceptable.
case JsonTokenType.StartObject:
case JsonTokenType.StartArray:
{
// 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);
}
// Back up to be at the beginning of the { or [, vs the end.
startingOffset--;
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);
int openQuote = checked ((int)startingOffset) - payloadLength;
ReadOnlySpan <byte> readerSpan = reader.OriginalSpan;
Debug.Assert(
readerSpan[openQuote] == (byte)'"',
$"Calculated span starts with {readerSpan[openQuote]}");
Debug.Assert(
readerSpan[(int)startingOffset - 1] == (byte)'"',
$"Calculated span ends with {readerSpan[(int)startingOffset - 1]}");
valueSpan = readerSpan.Slice(openQuote, payloadLength);
}
else
{
long payloadLength = 2;
if (reader.HasValueSequence)
{
payloadLength += reader.ValueSequence.Length;
}
else
{
payloadLength += reader.ValueSpan.Length;
}
valueSequence = sequence.Slice(startingOffset - payloadLength, payloadLength);
Debug.Assert(
valueSequence.First.Span[0] == (byte)'"',
$"Calculated sequence starts with {valueSequence.First.Span[0]}");
}
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;
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(tokenType))
{
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 reader, ref readStack);
}
}
else if (tokenType == JsonTokenType.EndObject)
{
if (readStack.Current.Drain)
{
readStack.Pop();
}
else if (readStack.Current.IsProcessingDictionary || readStack.Current.IsProcessingIDictionaryConstructible)
{
HandleEndDictionary(options, ref reader, ref readStack);
}
else
{
HandleEndObject(options, ref reader, ref readStack);
}
}
else if (tokenType == JsonTokenType.StartArray)
{
if (!readStack.Current.IsProcessingValue(tokenType))
{
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, options);
}
}
}
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;
}
public static object ReturnObjectHelper(byte[] data, JsonCommentHandling commentHandling = JsonCommentHandling.Disallow)
{
var state = new JsonReaderState(options: new JsonReaderOptions { CommentHandling = commentHandling });
var reader = new Utf8JsonReader(data, true, state);
return ReaderLoop(ref reader);
}
internal static TValue ContinueDeserialize <TValue>(
ref ReadBufferState bufferState,
ref JsonReaderState jsonReaderState,
ref ReadStack readStack,
JsonConverter converter,
JsonSerializerOptions options)
{
if (bufferState.BytesInBuffer > bufferState.ClearMax)
{
bufferState.ClearMax = bufferState.BytesInBuffer;
}
int start = 0;
if (bufferState.IsFirstIteration)
{
bufferState.IsFirstIteration = false;
// Handle the UTF-8 BOM if present
Debug.Assert(bufferState.Buffer.Length >= JsonConstants.Utf8Bom.Length);
if (bufferState.Buffer.AsSpan().StartsWith(JsonConstants.Utf8Bom))
{
start += JsonConstants.Utf8Bom.Length;
bufferState.BytesInBuffer -= JsonConstants.Utf8Bom.Length;
}
}
// Process the data available
TValue value = ReadCore <TValue>(
ref jsonReaderState,
bufferState.IsFinalBlock,
new ReadOnlySpan <byte>(bufferState.Buffer, start, bufferState.BytesInBuffer),
options,
ref readStack,
converter);
Debug.Assert(readStack.BytesConsumed <= bufferState.BytesInBuffer);
int bytesConsumed = checked ((int)readStack.BytesConsumed);
bufferState.BytesInBuffer -= bytesConsumed;
// The reader should have thrown if we have remaining bytes.
Debug.Assert(!bufferState.IsFinalBlock || bufferState.BytesInBuffer == 0);
if (!bufferState.IsFinalBlock)
{
// Check if we need to shift or expand the buffer because there wasn't enough data to complete deserialization.
if ((uint)bufferState.BytesInBuffer > ((uint)bufferState.Buffer.Length / 2))
{
// We have less than half the buffer available, double the buffer size.
byte[] oldBuffer = bufferState.Buffer;
int oldClearMax = bufferState.ClearMax;
byte[] newBuffer = ArrayPool <byte> .Shared.Rent((bufferState.Buffer.Length < (int.MaxValue / 2))?bufferState.Buffer.Length * 2 : int.MaxValue);
// Copy the unprocessed data to the new buffer while shifting the processed bytes.
Buffer.BlockCopy(oldBuffer, bytesConsumed + start, newBuffer, 0, bufferState.BytesInBuffer);
bufferState.Buffer = newBuffer;
bufferState.ClearMax = bufferState.BytesInBuffer;
// Clear and return the old buffer
new Span <byte>(oldBuffer, 0, oldClearMax).Clear();
ArrayPool <byte> .Shared.Return(oldBuffer);
}
else if (bufferState.BytesInBuffer != 0)
{
// Shift the processed bytes to the beginning of buffer to make more room.
Buffer.BlockCopy(bufferState.Buffer, bytesConsumed + start, bufferState.Buffer, 0, bufferState.BytesInBuffer);
}
}
return(value);
}
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);
}
}
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);
}
/// <summary>
/// Parse the text representing a single JSON value into a <paramref name="returnType"/>.
/// </summary>
/// <returns>A <paramref name="returnType"/> representation of the JSON value.</returns>
/// <param name="json">JSON text to parse.</param>
/// <param name="returnType">The type of the object to convert to and return.</param>
/// <param name="options">Options to control the behavior during parsing.</param>
/// <exception cref="System.ArgumentNullException">
/// Thrown if <paramref name="json"/> or <paramref name="returnType"/> is null.
/// </exception>
/// <exception cref="JsonException">
/// Thrown when the JSON is invalid,
/// the <paramref name="returnType"/> is not compatible with the JSON,
/// or when there is remaining data in the Stream.
/// </exception>
/// <remarks>Using a <see cref="string"/> is not as efficient as using the
/// UTF-8 methods since the implementation natively uses UTF-8.
/// </remarks>
public static object Deserialize(string json, Type returnType, JsonSerializerOptions options = null)
{
if (json == null)
{
throw new ArgumentNullException(nameof(json));
}
if (returnType == null)
{
throw new ArgumentNullException(nameof(returnType));
}
if (options == null)
{
options = JsonSerializerOptions.s_defaultOptions;
}
object result;
byte[] tempArray = null;
int maxBytes;
// For performance, avoid asking for the actual byte count unless necessary.
if (json.Length > MaxArrayLengthBeforeCalculatingSize)
{
// Get the actual byte count in order to handle large input.
maxBytes = JsonReaderHelper.GetUtf8ByteCount(json.AsSpan());
}
else
{
maxBytes = json.Length * JsonConstants.MaxExpansionFactorWhileTranscoding;
}
Span <byte> utf8 = maxBytes <= JsonConstants.StackallocThreshold ?
stackalloc byte[maxBytes] :
(tempArray = ArrayPool <byte> .Shared.Rent(maxBytes));
try
{
int actualByteCount = JsonReaderHelper.GetUtf8FromText(json.AsSpan(), utf8);
utf8 = utf8.Slice(0, actualByteCount);
var readerState = new JsonReaderState(options.GetReaderOptions());
var reader = new Utf8JsonReader(utf8, isFinalBlock: true, readerState);
result = ReadCore(returnType, options, ref reader);
if (reader.BytesConsumed != actualByteCount)
{
ThrowHelper.ThrowJsonException_DeserializeDataRemaining(
actualByteCount, actualByteCount - reader.BytesConsumed);
}
}
finally
{
if (tempArray != null)
{
utf8.Clear();
ArrayPool <byte> .Shared.Return(tempArray);
}
}
return(result);
}
