/// <summary>
/// Tries to merge a field from the coded input, returning true if the field was merged.
/// If the set is null or the field was not otherwise merged, this returns false.
/// </summary>
public static bool TryMergeFieldFrom <TTarget>(ref ExtensionSet <TTarget> set, ref ParseContext ctx) where TTarget : IExtendableMessage <TTarget>
{
Extension extension;
int lastFieldNumber = WireFormat.GetTagFieldNumber(ctx.LastTag);
IExtensionValue extensionValue;
if (set != null && set.ValuesByNumber.TryGetValue(lastFieldNumber, out extensionValue))
{
extensionValue.MergeFrom(ref ctx);
return(true);
}
else if (ctx.ExtensionRegistry != null && ctx.ExtensionRegistry.ContainsInputField(ctx.LastTag, typeof(TTarget), out extension))
{
IExtensionValue value = extension.CreateValue();
value.MergeFrom(ref ctx);
set = (set ?? new ExtensionSet <TTarget>());
set.ValuesByNumber.Add(extension.FieldNumber, value);
return(true);
}
else
{
return(false);
}
}
/// <summary>
/// Parses the next tag.
/// If the end of logical stream was reached, an invalid tag of 0 is returned.
/// </summary>
public static uint ParseTag(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state)
{
// The "nextTag" logic is there only as an optimization for reading non-packed repeated / map
// fields and is strictly speaking not necessary.
// TODO(jtattermusch): look into simplifying the ParseTag logic.
if (state.hasNextTag)
{
state.lastTag = state.nextTag;
state.hasNextTag = false;
return(state.lastTag);
}
// Optimize for the incredibly common case of having at least two bytes left in the buffer,
// and those two bytes being enough to get the tag. This will be true for fields up to 4095.
if (state.bufferPos + 2 <= state.bufferSize)
{
int tmp = buffer[state.bufferPos++];
if (tmp < 128)
{
state.lastTag = (uint)tmp;
}
else
{
int result = tmp & 0x7f;
if ((tmp = buffer[state.bufferPos++]) < 128)
{
result |= tmp << 7;
state.lastTag = (uint)result;
}
else
{
// Nope, rewind and go the potentially slow route.
state.bufferPos -= 2;
state.lastTag = ParsingPrimitives.ParseRawVarint32(ref buffer, ref state);
}
}
}
else
{
if (SegmentedBufferHelper.IsAtEnd(ref buffer, ref state))
{
state.lastTag = 0;
return(0);
}
state.lastTag = ParsingPrimitives.ParseRawVarint32(ref buffer, ref state);
}
if (WireFormat.GetTagFieldNumber(state.lastTag) == 0)
{
// If we actually read a tag with a field of 0, that's not a valid tag.
throw InvalidProtocolBufferException.InvalidTag();
}
return(state.lastTag);
}
/// <summary>
/// Parse a single field from <paramref name="ctx"/> and merge it
/// into this set.
/// </summary>
/// <param name="ctx">The parse context from which to read the field</param>
/// <returns>false if the tag is an "end group" tag, true otherwise</returns>
private bool MergeFieldFrom(ref ParseContext ctx)
{
uint tag = ctx.LastTag;
int number = WireFormat.GetTagFieldNumber(tag);
switch (WireFormat.GetTagWireType(tag))
{
case WireFormat.WireType.Varint:
{
ulong uint64 = ctx.ReadUInt64();
GetOrAddField(number).AddVarint(uint64);
return(true);
}
case WireFormat.WireType.Fixed32:
{
uint uint32 = ctx.ReadFixed32();
GetOrAddField(number).AddFixed32(uint32);
return(true);
}
case WireFormat.WireType.Fixed64:
{
ulong uint64 = ctx.ReadFixed64();
GetOrAddField(number).AddFixed64(uint64);
return(true);
}
case WireFormat.WireType.LengthDelimited:
{
ByteString bytes = ctx.ReadBytes();
GetOrAddField(number).AddLengthDelimited(bytes);
return(true);
}
case WireFormat.WireType.StartGroup:
{
UnknownFieldSet set = new UnknownFieldSet();
ParsingPrimitivesMessages.ReadGroup(ref ctx, number, set);
GetOrAddField(number).AddGroup(set);
return(true);
}
case WireFormat.WireType.EndGroup:
{
return(false);
}
default:
throw InvalidProtocolBufferException.InvalidWireType();
}
}
public static void ReadGroup(ref ParseContext ctx, IMessage message)
{
if (ctx.state.recursionDepth >= ctx.state.recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
++ctx.state.recursionDepth;
uint tag = ctx.state.lastTag;
int fieldNumber = WireFormat.GetTagFieldNumber(tag);
ReadRawMessage(ref ctx, message);
CheckLastTagWas(ref ctx.state, WireFormat.MakeTag(fieldNumber, WireFormat.WireType.EndGroup));
--ctx.state.recursionDepth;
}
/// <summary>
/// Skip a group.
/// </summary>
public static void SkipGroup(ref ReadOnlySpan <byte> buffer, ref ParserInternalState state, uint startGroupTag)
{
// Note: Currently we expect this to be the way that groups are read. We could put the recursion
// depth changes into the ReadTag method instead, potentially...
state.recursionDepth++;
if (state.recursionDepth >= state.recursionLimit)
{
throw InvalidProtocolBufferException.RecursionLimitExceeded();
}
uint tag;
while (true)
{
tag = ParsingPrimitives.ParseTag(ref buffer, ref state);
if (tag == 0)
{
throw InvalidProtocolBufferException.TruncatedMessage();
}
// Can't call SkipLastField for this case- that would throw.
if (WireFormat.GetTagWireType(tag) == WireFormat.WireType.EndGroup)
{
break;
}
// This recursion will allow us to handle nested groups.
SkipLastField(ref buffer, ref state);
}
int startField = WireFormat.GetTagFieldNumber(startGroupTag);
int endField = WireFormat.GetTagFieldNumber(tag);
if (startField != endField)
{
throw new InvalidProtocolBufferException(
$"Mismatched end-group tag. Started with field {startField}; ended with field {endField}");
}
state.recursionDepth--;
}
internal bool ContainsInputField(uint lastTag, Type target, out Extension extension)
{
return(extensions.TryGetValue(new ObjectIntPair <Type>(target, WireFormat.GetTagFieldNumber(lastTag)), out extension));
}
