292 lines
13 KiB
C#
292 lines
13 KiB
C#
#region Copyright notice and license
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// Protocol Buffers - Google's data interchange format
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// Copyright 2008 Google Inc. All rights reserved.
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// https://developers.google.com/protocol-buffers/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#endregion
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using System;
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using System.Buffers;
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using System.Collections.Generic;
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using System.IO;
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using System.Runtime.CompilerServices;
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using System.Security;
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using LC.Google.Protobuf.Collections;
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namespace LC.Google.Protobuf
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{
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/// <summary>
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/// Reading and skipping messages / groups
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/// </summary>
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[SecuritySafeCritical]
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internal static class ParsingPrimitivesMessages
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{
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private static readonly byte[] ZeroLengthMessageStreamData = new byte[] { 0 };
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public static void SkipLastField(ref ReadOnlySpan<byte> buffer, ref ParserInternalState state)
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{
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if (state.lastTag == 0)
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{
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throw new InvalidOperationException("SkipLastField cannot be called at the end of a stream");
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}
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switch (WireFormat.GetTagWireType(state.lastTag))
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{
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case WireFormat.WireType.StartGroup:
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SkipGroup(ref buffer, ref state, state.lastTag);
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break;
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case WireFormat.WireType.EndGroup:
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throw new InvalidProtocolBufferException(
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"SkipLastField called on an end-group tag, indicating that the corresponding start-group was missing");
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case WireFormat.WireType.Fixed32:
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ParsingPrimitives.ParseRawLittleEndian32(ref buffer, ref state);
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break;
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case WireFormat.WireType.Fixed64:
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ParsingPrimitives.ParseRawLittleEndian64(ref buffer, ref state);
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break;
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case WireFormat.WireType.LengthDelimited:
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var length = ParsingPrimitives.ParseLength(ref buffer, ref state);
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ParsingPrimitives.SkipRawBytes(ref buffer, ref state, length);
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break;
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case WireFormat.WireType.Varint:
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ParsingPrimitives.ParseRawVarint32(ref buffer, ref state);
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break;
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}
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}
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/// <summary>
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/// Skip a group.
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/// </summary>
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public static void SkipGroup(ref ReadOnlySpan<byte> buffer, ref ParserInternalState state, uint startGroupTag)
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{
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// Note: Currently we expect this to be the way that groups are read. We could put the recursion
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// depth changes into the ReadTag method instead, potentially...
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state.recursionDepth++;
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if (state.recursionDepth >= state.recursionLimit)
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{
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throw InvalidProtocolBufferException.RecursionLimitExceeded();
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}
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uint tag;
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while (true)
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{
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tag = ParsingPrimitives.ParseTag(ref buffer, ref state);
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if (tag == 0)
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{
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throw InvalidProtocolBufferException.TruncatedMessage();
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}
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// Can't call SkipLastField for this case- that would throw.
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if (WireFormat.GetTagWireType(tag) == WireFormat.WireType.EndGroup)
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{
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break;
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}
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// This recursion will allow us to handle nested groups.
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SkipLastField(ref buffer, ref state);
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}
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int startField = WireFormat.GetTagFieldNumber(startGroupTag);
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int endField = WireFormat.GetTagFieldNumber(tag);
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if (startField != endField)
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{
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throw new InvalidProtocolBufferException(
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$"Mismatched end-group tag. Started with field {startField}; ended with field {endField}");
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}
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state.recursionDepth--;
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}
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public static void ReadMessage(ref ParseContext ctx, IMessage message)
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{
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int length = ParsingPrimitives.ParseLength(ref ctx.buffer, ref ctx.state);
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if (ctx.state.recursionDepth >= ctx.state.recursionLimit)
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{
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throw InvalidProtocolBufferException.RecursionLimitExceeded();
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}
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int oldLimit = SegmentedBufferHelper.PushLimit(ref ctx.state, length);
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++ctx.state.recursionDepth;
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ReadRawMessage(ref ctx, message);
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CheckReadEndOfStreamTag(ref ctx.state);
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// Check that we've read exactly as much data as expected.
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if (!SegmentedBufferHelper.IsReachedLimit(ref ctx.state))
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{
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throw InvalidProtocolBufferException.TruncatedMessage();
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}
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--ctx.state.recursionDepth;
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SegmentedBufferHelper.PopLimit(ref ctx.state, oldLimit);
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}
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public static KeyValuePair<TKey, TValue> ReadMapEntry<TKey, TValue>(ref ParseContext ctx, MapField<TKey, TValue>.Codec codec)
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{
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int length = ParsingPrimitives.ParseLength(ref ctx.buffer, ref ctx.state);
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if (ctx.state.recursionDepth >= ctx.state.recursionLimit)
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{
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throw InvalidProtocolBufferException.RecursionLimitExceeded();
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}
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int oldLimit = SegmentedBufferHelper.PushLimit(ref ctx.state, length);
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++ctx.state.recursionDepth;
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TKey key = codec.KeyCodec.DefaultValue;
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TValue value = codec.ValueCodec.DefaultValue;
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uint tag;
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while ((tag = ctx.ReadTag()) != 0)
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{
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if (tag == codec.KeyCodec.Tag)
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{
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key = codec.KeyCodec.Read(ref ctx);
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}
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else if (tag == codec.ValueCodec.Tag)
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{
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value = codec.ValueCodec.Read(ref ctx);
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}
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else
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{
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SkipLastField(ref ctx.buffer, ref ctx.state);
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}
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}
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// Corner case: a map entry with a key but no value, where the value type is a message.
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// Read it as if we'd seen input with no data (i.e. create a "default" message).
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if (value == null)
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{
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if (ctx.state.CodedInputStream != null)
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{
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// the decoded message might not support parsing from ParseContext, so
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// we need to allow fallback to the legacy MergeFrom(CodedInputStream) parsing.
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value = codec.ValueCodec.Read(new CodedInputStream(ZeroLengthMessageStreamData));
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}
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else
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{
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ParseContext.Initialize(new ReadOnlySequence<byte>(ZeroLengthMessageStreamData), out ParseContext zeroLengthCtx);
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value = codec.ValueCodec.Read(ref zeroLengthCtx);
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}
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}
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CheckReadEndOfStreamTag(ref ctx.state);
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// Check that we've read exactly as much data as expected.
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if (!SegmentedBufferHelper.IsReachedLimit(ref ctx.state))
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{
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throw InvalidProtocolBufferException.TruncatedMessage();
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}
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--ctx.state.recursionDepth;
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SegmentedBufferHelper.PopLimit(ref ctx.state, oldLimit);
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return new KeyValuePair<TKey, TValue>(key, value);
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}
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public static void ReadGroup(ref ParseContext ctx, IMessage message)
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{
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if (ctx.state.recursionDepth >= ctx.state.recursionLimit)
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{
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throw InvalidProtocolBufferException.RecursionLimitExceeded();
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}
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++ctx.state.recursionDepth;
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uint tag = ctx.state.lastTag;
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int fieldNumber = WireFormat.GetTagFieldNumber(tag);
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ReadRawMessage(ref ctx, message);
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CheckLastTagWas(ref ctx.state, WireFormat.MakeTag(fieldNumber, WireFormat.WireType.EndGroup));
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--ctx.state.recursionDepth;
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}
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public static void ReadGroup(ref ParseContext ctx, int fieldNumber, UnknownFieldSet set)
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{
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if (ctx.state.recursionDepth >= ctx.state.recursionLimit)
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{
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throw InvalidProtocolBufferException.RecursionLimitExceeded();
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}
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++ctx.state.recursionDepth;
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set.MergeGroupFrom(ref ctx);
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CheckLastTagWas(ref ctx.state, WireFormat.MakeTag(fieldNumber, WireFormat.WireType.EndGroup));
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--ctx.state.recursionDepth;
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}
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public static void ReadRawMessage(ref ParseContext ctx, IMessage message)
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{
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if (message is IBufferMessage bufferMessage)
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{
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bufferMessage.InternalMergeFrom(ref ctx);
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}
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else
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{
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// If we reached here, it means we've ran into a nested message with older generated code
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// which doesn't provide the InternalMergeFrom method that takes a ParseContext.
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// With a slight performance overhead, we can still parse this message just fine,
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// but we need to find the original CodedInputStream instance that initiated this
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// parsing process and make sure its internal state is up to date.
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// Note that this performance overhead is not very high (basically copying contents of a struct)
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// and it will only be incurred in case the application mixes older and newer generated code.
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// Regenerating the code from .proto files will remove this overhead because it will
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// generate the InternalMergeFrom method we need.
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if (ctx.state.CodedInputStream == null)
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{
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// This can only happen when the parsing started without providing a CodedInputStream instance
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// (e.g. ParseContext was created directly from a ReadOnlySequence).
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// That also means that one of the new parsing APIs was used at the top level
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// and in such case it is reasonable to require that all the nested message provide
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// up-to-date generated code with ParseContext support (and fail otherwise).
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throw new InvalidProtocolBufferException($"Message {message.GetType().Name} doesn't provide the generated method that enables ParseContext-based parsing. You might need to regenerate the generated protobuf code.");
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}
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ctx.CopyStateTo(ctx.state.CodedInputStream);
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try
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{
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// fallback parse using the CodedInputStream that started current parsing tree
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message.MergeFrom(ctx.state.CodedInputStream);
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}
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finally
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{
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ctx.LoadStateFrom(ctx.state.CodedInputStream);
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}
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}
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}
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/// <summary>
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/// Verifies that the last call to ReadTag() returned tag 0 - in other words,
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/// we've reached the end of the stream when we expected to.
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/// </summary>
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/// <exception cref="InvalidProtocolBufferException">The
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/// tag read was not the one specified</exception>
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public static void CheckReadEndOfStreamTag(ref ParserInternalState state)
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{
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if (state.lastTag != 0)
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{
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throw InvalidProtocolBufferException.MoreDataAvailable();
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}
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}
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private static void CheckLastTagWas(ref ParserInternalState state, uint expectedTag)
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{
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if (state.lastTag != expectedTag) {
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throw InvalidProtocolBufferException.InvalidEndTag();
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}
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}
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}
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} |