/// <summary>
/// Given the EventPipe metaData header and a stream pointing at the serialized meta-data for the parameters for the
/// event, create a new DynamicTraceEventData that knows how to parse that event.
/// ReaderForParameters.Current is advanced past the parameter information.
/// </summary>
private DynamicTraceEventData ReadEventParametersAndBuildTemplate(EventPipeEventMetaDataHeader eventMetaDataHeader, PinnedStreamReader readerForParameters)
{
int opcode;
string opcodeName;
GetOpcodeFromEventName(eventMetaDataHeader.EventName, out opcode, out opcodeName);
DynamicTraceEventData.PayloadFetchClassInfo classInfo = null;
DynamicTraceEventData template = new DynamicTraceEventData(null, eventMetaDataHeader.EventId, 0, eventMetaDataHeader.EventName, Guid.Empty, opcode, opcodeName, eventMetaDataHeader.ProviderId, eventMetaDataHeader.ProviderName);
// If the metadata contains no parameter metadata, don't attempt to read it.
if (!eventMetaDataHeader.ContainsParameterMetadata)
{
template.payloadNames = new string[0];
template.payloadFetches = new DynamicTraceEventData.PayloadFetch[0];
return(template);
}
// Read the count of event payload fields.
int fieldCount = readerForParameters.ReadInt32();
Debug.Assert(0 <= fieldCount && fieldCount < 0x4000);
if (fieldCount > 0)
{
// Recursively parse the metadata, building up a list of payload names and payload field fetch objects.
classInfo = ParseFields(readerForParameters, fieldCount);
}
else
{
classInfo = new DynamicTraceEventData.PayloadFetchClassInfo()
{
FieldNames = new string[0],
FieldFetches = new DynamicTraceEventData.PayloadFetch[0]
};
}
template.payloadNames = classInfo.FieldNames;
template.payloadFetches = classInfo.FieldFetches;
return(template);
}
private DynamicTraceEventData.PayloadFetchClassInfo ParseFields(PinnedStreamReader reader, int numFields)
{
string[] fieldNames = new string[numFields];
DynamicTraceEventData.PayloadFetch[] fieldFetches = new DynamicTraceEventData.PayloadFetch[numFields];
ushort offset = 0;
for (int fieldIndex = 0; fieldIndex < numFields; fieldIndex++)
{
DynamicTraceEventData.PayloadFetch payloadFetch = new DynamicTraceEventData.PayloadFetch();
// Read the TypeCode for the current field.
TypeCode typeCode = (TypeCode)reader.ReadInt32();
// Fill out the payload fetch object based on the TypeCode.
switch (typeCode)
{
case TypeCode.Boolean:
{
payloadFetch.Type = typeof(bool);
payloadFetch.Size = 4; // We follow windows conventions and use 4 bytes for bool.
payloadFetch.Offset = offset;
break;
}
case TypeCode.Char:
{
payloadFetch.Type = typeof(char);
payloadFetch.Size = sizeof(char);
payloadFetch.Offset = offset;
break;
}
case TypeCode.SByte:
{
payloadFetch.Type = typeof(SByte);
payloadFetch.Size = sizeof(SByte);
payloadFetch.Offset = offset;
break;
}
case TypeCode.Byte:
{
payloadFetch.Type = typeof(byte);
payloadFetch.Size = sizeof(byte);
payloadFetch.Offset = offset;
break;
}
case TypeCode.Int16:
{
payloadFetch.Type = typeof(Int16);
payloadFetch.Size = sizeof(Int16);
payloadFetch.Offset = offset;
break;
}
case TypeCode.UInt16:
{
payloadFetch.Type = typeof(UInt16);
payloadFetch.Size = sizeof(UInt16);
payloadFetch.Offset = offset;
break;
}
case TypeCode.Int32:
{
payloadFetch.Type = typeof(Int32);
payloadFetch.Size = sizeof(Int32);
payloadFetch.Offset = offset;
break;
}
case TypeCode.UInt32:
{
payloadFetch.Type = typeof(UInt32);
payloadFetch.Size = sizeof(UInt32);
payloadFetch.Offset = offset;
break;
}
case TypeCode.Int64:
{
payloadFetch.Type = typeof(Int64);
payloadFetch.Size = sizeof(Int64);
payloadFetch.Offset = offset;
break;
}
case TypeCode.UInt64:
{
payloadFetch.Type = typeof(UInt64);
payloadFetch.Size = sizeof(UInt64);
payloadFetch.Offset = offset;
break;
}
case TypeCode.Single:
{
payloadFetch.Type = typeof(Single);
payloadFetch.Size = sizeof(Single);
payloadFetch.Offset = offset;
break;
}
case TypeCode.Double:
{
payloadFetch.Type = typeof(Double);
payloadFetch.Size = sizeof(Double);
payloadFetch.Offset = offset;
break;
}
case TypeCode.Decimal:
{
payloadFetch.Type = typeof(Decimal);
payloadFetch.Size = sizeof(Decimal);
payloadFetch.Offset = offset;
break;
}
case TypeCode.DateTime:
{
payloadFetch.Type = typeof(DateTime);
payloadFetch.Size = 8;
payloadFetch.Offset = offset;
break;
}
case EventPipeEventSource.GuidTypeCode:
{
payloadFetch.Type = typeof(Guid);
payloadFetch.Size = 16;
payloadFetch.Offset = offset;
break;
}
case TypeCode.String:
{
payloadFetch.Type = typeof(String);
payloadFetch.Size = DynamicTraceEventData.NULL_TERMINATED;
payloadFetch.Offset = offset;
break;
}
case TypeCode.Object:
{
// TypeCode.Object represents an embedded struct.
// Read the number of fields in the struct. Each of these fields could be an embedded struct,
// but these embedded structs are still counted as single fields. They will be expanded when they are handled.
int structFieldCount = reader.ReadInt32();
DynamicTraceEventData.PayloadFetchClassInfo embeddedStructClassInfo = ParseFields(reader, structFieldCount);
if (embeddedStructClassInfo == null)
{
throw new Exception("Unable to parse metadata for embedded struct.");
}
payloadFetch = DynamicTraceEventData.PayloadFetch.StructPayloadFetch(offset, embeddedStructClassInfo);
break;
}
default:
{
throw new NotSupportedException($"{typeCode} is not supported.");
}
}
// Read the string name of the event payload field.
fieldNames[fieldIndex] = reader.ReadNullTerminatedUnicodeString();
// Update the offset into the event for the next payload fetch.
if (payloadFetch.Size >= DynamicTraceEventData.SPECIAL_SIZES || offset == ushort.MaxValue)
{
offset = ushort.MaxValue; // Indicate that the offset must be computed at run time.
}
else
{
offset += payloadFetch.Size;
}
// Save the current payload fetch.
fieldFetches[fieldIndex] = payloadFetch;
}
return(new DynamicTraceEventData.PayloadFetchClassInfo()
{
FieldNames = fieldNames,
FieldFetches = fieldFetches
});
}