/// <summary>
/// Verifies that the last call to ReadTag() returned the given tag value.
/// This is used to verify that a nested group ended with the correct
/// end tag.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">The last
/// tag read was not the one specified</exception>
public void CheckLastTagWas(uint value)
{
if (lastTag != value)
{
throw InvalidProtocolBufferException.InvalidEndTag();
}
}
/// <summary>
/// Called by MergeFieldFrom to parse a MessageSet extension.
/// </summary>
private void MergeMessageSetExtensionFromCodedStream(ICodedInputStream input,
ExtensionRegistry extensionRegistry, IBuilder builder)
{
MessageDescriptor type = builder.DescriptorForType;
// The wire format for MessageSet is:
// message MessageSet {
// repeated group Item = 1 {
// required int32 typeId = 2;
// required bytes message = 3;
// }
// }
// "typeId" is the extension's field number. The extension can only be
// a message type, where "message" contains the encoded bytes of that
// message.
//
// In practice, we will probably never see a MessageSet item in which
// the message appears before the type ID, or where either field does not
// appear exactly once. However, in theory such cases are valid, so we
// should be prepared to accept them.
int typeId = 0;
ByteString rawBytes = null; // If we encounter "message" before "typeId"
IBuilderLite subBuilder = null;
FieldDescriptor field = null;
uint lastTag = WireFormat.MessageSetTag.ItemStart;
uint tag;
string name;
while (input.ReadTag(out tag, out name))
{
if (tag == 0 && name != null)
{
if (name == "type_id")
{
tag = WireFormat.MessageSetTag.TypeID;
}
else if (name == "message")
{
tag = WireFormat.MessageSetTag.Message;
}
}
if (tag == 0)
{
if (input.SkipField())
{
continue; //can't merge unknown without field tag
}
break;
}
lastTag = tag;
if (tag == WireFormat.MessageSetTag.TypeID)
{
typeId = 0;
// Zero is not a valid type ID.
if (input.ReadInt32(ref typeId) && typeId != 0)
{
ExtensionInfo extension = extensionRegistry[type, typeId];
if (extension != null)
{
field = extension.Descriptor;
subBuilder = extension.DefaultInstance.WeakCreateBuilderForType();
IMessageLite originalMessage = (IMessageLite)builder[field];
if (originalMessage != null)
{
subBuilder.WeakMergeFrom(originalMessage);
}
if (rawBytes != null)
{
// We already encountered the message. Parse it now.
// TODO(jonskeet): Check this is okay. It's subtly different from the Java, as it doesn't create an input stream from rawBytes.
// In fact, why don't we just call MergeFrom(rawBytes)? And what about the extension registry?
subBuilder.WeakMergeFrom(rawBytes.CreateCodedInput());
rawBytes = null;
}
}
else
{
// Unknown extension number. If we already saw data, put it
// in rawBytes.
if (rawBytes != null)
{
MergeField(typeId, UnknownField.CreateBuilder().AddLengthDelimited(rawBytes).Build());
rawBytes = null;
}
}
}
}
else if (tag == WireFormat.MessageSetTag.Message)
{
if (subBuilder != null)
{
// We already know the type, so we can parse directly from the input
// with no copying. Hooray!
input.ReadMessage(subBuilder, extensionRegistry);
}
else if (input.ReadBytes(ref rawBytes))
{
if (typeId != 0)
{
// We don't know how to parse this. Ignore it.
MergeField(typeId,
UnknownField.CreateBuilder().AddLengthDelimited(rawBytes).Build());
}
}
}
else
{
// Unknown tag. Skip it.
if (!input.SkipField())
{
break; // end of group
}
}
}
if (lastTag != WireFormat.MessageSetTag.ItemEnd)
{
throw InvalidProtocolBufferException.InvalidEndTag();
}
if (subBuilder != null)
{
builder[field] = subBuilder.WeakBuild();
}
}