#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion
using Google.Protobuf.Collections;
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Security;
namespace Google.Protobuf
{
/// <summary>
/// Reads and decodes protocol message fields.
/// </summary>
/// <remarks>
/// <para>
/// This class is generally used by generated code to read appropriate
/// primitives from the stream. It effectively encapsulates the lowest
/// levels of protocol buffer format.
/// </para>
/// <para>
/// Repeated fields and map fields are not handled by this class; use <see cref="RepeatedField{T}"/>
/// and <see cref="MapField{TKey, TValue}"/> to serialize such fields.
/// </para>
/// </remarks>
[SecuritySafeCritical]
public sealed class CodedInputStream : IDisposable
{
/// <summary>
/// Whether to leave the underlying stream open when disposing of this stream.
/// This is always true when there's no stream.
/// </summary>
private readonly bool leaveOpen;
/// <summary>
/// Buffer of data read from the stream or provided at construction time.
/// </summary>
private readonly byte[] buffer;
/// <summary>
/// The stream to read further input from, or null if the byte array buffer was provided
/// directly on construction, with no further data available.
/// </summary>
private readonly Stream input;
/// <summary>
/// The parser state is kept separately so that other parse implementations can reuse the same
/// parsing primitives.
/// </summary>
private ParserInternalState state;
internal const int DefaultRecursionLimit = 100;
internal const int DefaultSizeLimit = Int32.MaxValue;
internal const int BufferSize = 4096;
#region Construction
// Note that the checks are performed such that we don't end up checking obviously-valid things
// like non-null references for arrays we've just created.
/// <summary>
/// Creates a new CodedInputStream reading data from the given byte array.
/// </summary>
public CodedInputStream(byte[] buffer) : this(null, ProtoPreconditions.CheckNotNull(buffer, "buffer"), 0, buffer.Length, true)
{
}
/// <summary>
/// Creates a new <see cref="CodedInputStream"/> that reads from the given byte array slice.
/// </summary>
public CodedInputStream(byte[] buffer, int offset, int length)
: this(null, ProtoPreconditions.CheckNotNull(buffer, "buffer"), offset, offset + length, true)
{
if (offset < 0 || offset > buffer.Length)
{
throw new ArgumentOutOfRangeException("offset", "Offset must be within the buffer");
}
if (length < 0 || offset + length > buffer.Length)
{
throw new ArgumentOutOfRangeException("length", "Length must be non-negative and within the buffer");
}
}
/// <summary>
/// Creates a new <see cref="CodedInputStream"/> reading data from the given stream, which will be disposed
/// when the returned object is disposed.
/// </summary>
/// <param name="input">The stream to read from.</param>
public CodedInputStream(Stream input) : this(input, false)
{
}
/// <summary>
/// Creates a new <see cref="CodedInputStream"/> reading data from the given stream.
/// </summary>
/// <param name="input">The stream to read from.</param>
/// <param name="leaveOpen"><c>true</c> to leave <paramref name="input"/> open when the returned
/// <c cref="CodedInputStream"/> is disposed; <c>false</c> to dispose of the given stream when the
/// returned object is disposed.</param>
public CodedInputStream(Stream input, bool leaveOpen)
: this(ProtoPreconditions.CheckNotNull(input, "input"), new byte[BufferSize], 0, 0, leaveOpen)
{
}
/// <summary>
/// Creates a new CodedInputStream reading data from the given
/// stream and buffer, using the default limits.
/// </summary>
internal CodedInputStream(Stream input, byte[] buffer, int bufferPos, int bufferSize, bool leaveOpen)
{
this.input = input;
this.buffer = buffer;
this.state.bufferPos = bufferPos;
this.state.bufferSize = bufferSize;
this.state.sizeLimit = DefaultSizeLimit;
this.state.recursionLimit = DefaultRecursionLimit;
SegmentedBufferHelper.Initialize(this, out this.state.segmentedBufferHelper);
this.leaveOpen = leaveOpen;
this.state.currentLimit = int.MaxValue;
}
/// <summary>
/// Creates a new CodedInputStream reading data from the given
/// stream and buffer, using the specified limits.
/// </summary>
/// <remarks>
/// This chains to the version with the default limits instead of vice versa to avoid
/// having to check that the default values are valid every time.
/// </remarks>
internal CodedInputStream(Stream input, byte[] buffer, int bufferPos, int bufferSize, int sizeLimit, int recursionLimit, bool leaveOpen)
: this(input, buffer, bufferPos, bufferSize, leaveOpen)
{
if (sizeLimit <= 0)
{
throw new ArgumentOutOfRangeException("sizeLimit", "Size limit must be positive");
}
if (recursionLimit <= 0)
{
throw new ArgumentOutOfRangeException("recursionLimit!", "Recursion limit must be positive");
}
this.state.sizeLimit = sizeLimit;
this.state.recursionLimit = recursionLimit;
}
#endregion
/// <summary>
/// Creates a <see cref="CodedInputStream"/> with the specified size and recursion limits, reading
/// from an input stream.
/// </summary>
/// <remarks>
/// This method exists separately from the constructor to reduce the number of constructor overloads.
/// It is likely to be used considerably less frequently than the constructors, as the default limits
/// are suitable for most use cases.
/// </remarks>
/// <param name="input">The input stream to read from</param>
/// <param name="sizeLimit">The total limit of data to read from the stream.</param>
/// <param name="recursionLimit">The maximum recursion depth to allow while reading.</param>
/// <returns>A <c>CodedInputStream</c> reading from <paramref name="input"/> with the specified size
/// and recursion limits.</returns>
public static CodedInputStream CreateWithLimits(Stream input, int sizeLimit, int recursionLimit)
{
// Note: we may want an overload accepting leaveOpen
return new CodedInputStream(input, new byte[BufferSize], 0, 0, sizeLimit, recursionLimit, false);
}
/// <summary>
/// Returns the current position in the input stream, or the position in the input buffer
/// </summary>
public long Position
{
get
{
if (input != null)
{
return input.Position - ((state.bufferSize + state.bufferSizeAfterLimit) - state.bufferPos);
}
return state.bufferPos;
}
}
/// <summary>
/// Returns the last tag read, or 0 if no tags have been read or we've read beyond
/// the end of the stream.
/// </summary>
internal uint LastTag { get { return state.lastTag; } }
/// <summary>
/// Returns the size limit for this stream.
/// </summary>
/// <remarks>
/// This limit is applied when reading from the underlying stream, as a sanity check. It is
/// not applied when reading from a byte array data source without an underlying stream.
/// The default value is Int32.MaxValue.
/// </remarks>
/// <value>
/// The size limit.
/// </value>
public int SizeLimit { get { return state.sizeLimit; } }
/// <summary>
/// Returns the recursion limit for this stream. This limit is applied whilst reading messages,
/// to avoid maliciously-recursive data.
/// </summary>
/// <remarks>
/// The default limit is 100.
/// </remarks>
/// <value>
/// The recursion limit for this stream.
/// </value>
public int RecursionLimit { get { return state.recursionLimit; } }
/// <summary>
/// Internal-only property; when set to true, unknown fields will be discarded while parsing.
/// </summary>
internal bool DiscardUnknownFields
{
get { return state.DiscardUnknownFields; }
set { state.DiscardUnknownFields = value; }
}
/// <summary>
/// Internal-only property; provides extension identifiers to compatible messages while parsing.
/// </summary>
internal ExtensionRegistry ExtensionRegistry
{
get { return state.ExtensionRegistry; }
set { state.ExtensionRegistry = value; }
}
internal byte[] InternalBuffer => buffer;
internal Stream InternalInputStream => input;
internal ref ParserInternalState InternalState => ref state;
/// <summary>
/// Disposes of this instance, potentially closing any underlying stream.
/// </summary>
/// <remarks>
/// As there is no flushing to perform here, disposing of a <see cref="CodedInputStream"/> which
/// was constructed with the <c>leaveOpen</c> option parameter set to <c>true</c> (or one which
/// was constructed to read from a byte array) has no effect.
/// </remarks>
public void Dispose()
{
if (!leaveOpen)
{
input.Dispose();
}
}
#region Validation
/// <summary>
/// Verifies that the last call to ReadTag() returned tag 0 - in other words,
/// we've reached the end of the stream when we expected to.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">The
/// tag read was not the one specified</exception>
internal void CheckReadEndOfStreamTag()
{
ParsingPrimitivesMessages.CheckReadEndOfStreamTag(ref state);
}
#endregion
#region Reading of tags etc
/// <summary>
/// Peeks at the next field tag. This is like calling <see cref="ReadTag"/>, but the
/// tag is not consumed. (So a subsequent call to <see cref="ReadTag"/> will return the
/// same value.)
/// </summary>
public uint PeekTag()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.PeekTag(ref span, ref state);
}
/// <summary>
/// Reads a field tag, returning the tag of 0 for "end of stream".
/// </summary>
/// <remarks>
/// If this method returns 0, it doesn't necessarily mean the end of all
/// the data in this CodedInputStream; it may be the end of the logical stream
/// for an embedded message, for example.
/// </remarks>
/// <returns>The next field tag, or 0 for end of stream. (0 is never a valid tag.)</returns>
public uint ReadTag()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseTag(ref span, ref state);
}
/// <summary>
/// Skips the data for the field with the tag we've just read.
/// This should be called directly after <see cref="ReadTag"/>, when
/// the caller wishes to skip an unknown field.
/// </summary>
/// <remarks>
/// This method throws <see cref="InvalidProtocolBufferException"/> if the last-read tag was an end-group tag.
/// If a caller wishes to skip a group, they should skip the whole group, by calling this method after reading the
/// start-group tag. This behavior allows callers to call this method on any field they don't understand, correctly
/// resulting in an error if an end-group tag has not been paired with an earlier start-group tag.
/// </remarks>
/// <exception cref="InvalidProtocolBufferException">The last tag was an end-group tag</exception>
/// <exception cref="InvalidOperationException">The last read operation read to the end of the logical stream</exception>
public void SkipLastField()
{
var span = new ReadOnlySpan<byte>(buffer);
ParsingPrimitivesMessages.SkipLastField(ref span, ref state);
}
/// <summary>
/// Skip a group.
/// </summary>
internal void SkipGroup(uint startGroupTag)
{
var span = new ReadOnlySpan<byte>(buffer);
ParsingPrimitivesMessages.SkipGroup(ref span, ref state, startGroupTag);
}
/// <summary>
/// Reads a double field from the stream.
/// </summary>
public double ReadDouble()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseDouble(ref span, ref state);
}
/// <summary>
/// Reads a float field from the stream.
/// </summary>
public float ReadFloat()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseFloat(ref span, ref state);
}
/// <summary>
/// Reads a uint64 field from the stream.
/// </summary>
public ulong ReadUInt64()
{
return ReadRawVarint64();
}
/// <summary>
/// Reads an int64 field from the stream.
/// </summary>
public long ReadInt64()
{
return (long) ReadRawVarint64();
}
/// <summary>
/// Reads an int32 field from the stream.
/// </summary>
public int ReadInt32()
{
return (int) ReadRawVarint32();
}
/// <summary>
/// Reads a fixed64 field from the stream.
/// </summary>
public ulong ReadFixed64()
{
return ReadRawLittleEndian64();
}
/// <summary>
/// Reads a fixed32 field from the stream.
/// </summary>
public uint ReadFixed32()
{
return ReadRawLittleEndian32();
}
/// <summary>
/// Reads a bool field from the stream.
/// </summary>
public bool ReadBool()
{
return ReadRawVarint64() != 0;
}
/// <summary>
/// Reads a string field from the stream.
/// </summary>
public string ReadString()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ReadString(ref span, ref state);
}
/// <summary>
/// Reads an embedded message field value from the stream.
/// </summary>
public void ReadMessage(IMessage builder)
{
// TODO(jtattermusch): if the message doesn't implement IBufferMessage (and thus does not provide the InternalMergeFrom method),
// what we're doing here works fine, but could be more efficient.
// What happens is that we first initialize a ParseContext from the current coded input stream only to parse the length of the message, at which point
// we will need to switch back again to CodedInputStream-based parsing (which involves copying and storing the state) to be able to
// invoke the legacy MergeFrom(CodedInputStream) method.
// For now, this inefficiency is fine, considering this is only a backward-compatibility scenario (and regenerating the code fixes it).
ParseContext.Initialize(buffer.AsSpan(), ref state, out ParseContext ctx);
try
{
ParsingPrimitivesMessages.ReadMessage(ref ctx, builder);
}
finally
{
ctx.CopyStateTo(this);
}
}
/// <summary>
/// Reads an embedded group field from the stream.
/// </summary>
public void ReadGroup(IMessage builder)
{
ParseContext.Initialize(this, out ParseContext ctx);
try
{
ParsingPrimitivesMessages.ReadGroup(ref ctx, builder);
}
finally
{
ctx.CopyStateTo(this);
}
}
/// <summary>
/// Reads a bytes field value from the stream.
/// </summary>
public ByteString ReadBytes()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ReadBytes(ref span, ref state);
}
/// <summary>
/// Reads a uint32 field value from the stream.
/// </summary>
public uint ReadUInt32()
{
return ReadRawVarint32();
}
/// <summary>
/// Reads an enum field value from the stream.
/// </summary>
public int ReadEnum()
{
// Currently just a pass-through, but it's nice to separate it logically from WriteInt32.
return (int) ReadRawVarint32();
}
/// <summary>
/// Reads an sfixed32 field value from the stream.
/// </summary>
public int ReadSFixed32()
{
return (int) ReadRawLittleEndian32();
}
/// <summary>
/// Reads an sfixed64 field value from the stream.
/// </summary>
public long ReadSFixed64()
{
return (long) ReadRawLittleEndian64();
}
/// <summary>
/// Reads an sint32 field value from the stream.
/// </summary>
public int ReadSInt32()
{
return ParsingPrimitives.DecodeZigZag32(ReadRawVarint32());
}
/// <summary>
/// Reads an sint64 field value from the stream.
/// </summary>
public long ReadSInt64()
{
return ParsingPrimitives.DecodeZigZag64(ReadRawVarint64());
}
/// <summary>
/// Reads a length for length-delimited data.
/// </summary>
/// <remarks>
/// This is internally just reading a varint, but this method exists
/// to make the calling code clearer.
/// </remarks>
public int ReadLength()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseLength(ref span, ref state);
}
/// <summary>
/// Peeks at the next tag in the stream. If it matches <paramref name="tag"/>,
/// the tag is consumed and the method returns <c>true</c>; otherwise, the
/// stream is left in the original position and the method returns <c>false</c>.
/// </summary>
public bool MaybeConsumeTag(uint tag)
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.MaybeConsumeTag(ref span, ref state, tag);
}
#endregion
#region Underlying reading primitives
/// <summary>
/// Reads a raw Varint from the stream. If larger than 32 bits, discard the upper bits.
/// This method is optimised for the case where we've got lots of data in the buffer.
/// That means we can check the size just once, then just read directly from the buffer
/// without constant rechecking of the buffer length.
/// </summary>
internal uint ReadRawVarint32()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseRawVarint32(ref span, ref state);
}
/// <summary>
/// Reads a varint from the input one byte at a time, so that it does not
/// read any bytes after the end of the varint. If you simply wrapped the
/// stream in a CodedInputStream and used ReadRawVarint32(Stream)
/// then you would probably end up reading past the end of the varint since
/// CodedInputStream buffers its input.
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
internal static uint ReadRawVarint32(Stream input)
{
return ParsingPrimitives.ReadRawVarint32(input);
}
/// <summary>
/// Reads a raw varint from the stream.
/// </summary>
internal ulong ReadRawVarint64()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseRawVarint64(ref span, ref state);
}
/// <summary>
/// Reads a 32-bit little-endian integer from the stream.
/// </summary>
internal uint ReadRawLittleEndian32()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseRawLittleEndian32(ref span, ref state);
}
/// <summary>
/// Reads a 64-bit little-endian integer from the stream.
/// </summary>
internal ulong ReadRawLittleEndian64()
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ParseRawLittleEndian64(ref span, ref state);
}
#endregion
#region Internal reading and buffer management
/// <summary>
/// Sets currentLimit to (current position) + byteLimit. This is called
/// when descending into a length-delimited embedded message. The previous
/// limit is returned.
/// </summary>
/// <returns>The old limit.</returns>
internal int PushLimit(int byteLimit)
{
return SegmentedBufferHelper.PushLimit(ref state, byteLimit);
}
/// <summary>
/// Discards the current limit, returning the previous limit.
/// </summary>
internal void PopLimit(int oldLimit)
{
SegmentedBufferHelper.PopLimit(ref state, oldLimit);
}
/// <summary>
/// Returns whether or not all the data before the limit has been read.
/// </summary>
/// <returns></returns>
internal bool ReachedLimit
{
get
{
return SegmentedBufferHelper.IsReachedLimit(ref state);
}
}
/// <summary>
/// Returns true if the stream has reached the end of the input. This is the
/// case if either the end of the underlying input source has been reached or
/// the stream has reached a limit created using PushLimit.
/// </summary>
public bool IsAtEnd
{
get
{
var span = new ReadOnlySpan<byte>(buffer);
return SegmentedBufferHelper.IsAtEnd(ref span, ref state);
}
}
/// <summary>
/// Called when buffer is empty to read more bytes from the
/// input. If <paramref name="mustSucceed"/> is true, RefillBuffer() guarantees that
/// either there will be at least one byte in the buffer when it returns
/// or it will throw an exception. If <paramref name="mustSucceed"/> is false,
/// RefillBuffer() returns false if no more bytes were available.
/// </summary>
/// <param name="mustSucceed"></param>
/// <returns></returns>
private bool RefillBuffer(bool mustSucceed)
{
var span = new ReadOnlySpan<byte>(buffer);
return state.segmentedBufferHelper.RefillBuffer(ref span, ref state, mustSucceed);
}
/// <summary>
/// Reads a fixed size of bytes from the input.
/// </summary>
/// <exception cref="InvalidProtocolBufferException">
/// the end of the stream or the current limit was reached
/// </exception>
internal byte[] ReadRawBytes(int size)
{
var span = new ReadOnlySpan<byte>(buffer);
return ParsingPrimitives.ReadRawBytes(ref span, ref state, size);
}
/// <summary>
/// Reads a top-level message or a nested message after the limits for this message have been pushed.
/// (parser will proceed until the end of the current limit)
/// NOTE: this method needs to be public because it's invoked by the generated code - e.g. msg.MergeFrom(CodedInputStream input) method
/// </summary>
public void ReadRawMessage(IMessage message)
{
ParseContext.Initialize(this, out ParseContext ctx);
try
{
ParsingPrimitivesMessages.ReadRawMessage(ref ctx, message);
}
finally
{
ctx.CopyStateTo(this);
}
}
#endregion
}
}
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