Change ReadTag and PeekTag to just use 0 as a return value for "end of stream", rather than using an awkward out parameter.
This simplifies quite a lot of code.
Generated code in next commit.
diff --git a/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs b/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs
index 408c7cb..23af288 100644
--- a/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs
+++ b/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs
@@ -38,8 +38,7 @@
{
public static void AssertNextTag(this CodedInputStream input, uint expectedTag)
{
- uint tag;
- Assert.IsTrue(input.ReadTag(out tag));
+ uint tag = input.ReadTag();
Assert.AreEqual(expectedTag, tag);
}
diff --git a/csharp/src/Google.Protobuf.Test/CodedInputStreamTest.cs b/csharp/src/Google.Protobuf.Test/CodedInputStreamTest.cs
index 6e25fa3..c4c92ef 100644
--- a/csharp/src/Google.Protobuf.Test/CodedInputStreamTest.cs
+++ b/csharp/src/Google.Protobuf.Test/CodedInputStreamTest.cs
@@ -279,9 +279,7 @@
ms.Position = 0;
CodedInputStream input = new CodedInputStream(ms);
- uint testtag;
- Assert.IsTrue(input.ReadTag(out testtag));
- Assert.AreEqual(tag, testtag);
+ Assert.AreEqual(tag, input.ReadTag());
// TODO(jonskeet): Should this be ArgumentNullException instead?
Assert.Throws<InvalidProtocolBufferException>(() => input.ReadBytes());
@@ -377,9 +375,7 @@
CodedInputStream input = new CodedInputStream(ms);
- uint actualTag;
- Assert.IsTrue(input.ReadTag(out actualTag));
- Assert.AreEqual(tag, actualTag);
+ Assert.AreEqual(tag, input.ReadTag());
string text = input.ReadString();
Assert.AreEqual('\ufffd', text[0]);
}
@@ -430,15 +426,21 @@
ms.Position = 0;
CodedInputStream input = new CodedInputStream(ms, new byte[ms.Length / 2]);
- uint tag;
- Assert.IsTrue(input.ReadTag(out tag));
+ uint tag = input.ReadTag();
Assert.AreEqual(1, WireFormat.GetTagFieldNumber(tag));
Assert.AreEqual(100, input.ReadBytes().Length);
- Assert.IsTrue(input.ReadTag(out tag));
+ tag = input.ReadTag();
Assert.AreEqual(2, WireFormat.GetTagFieldNumber(tag));
Assert.AreEqual(100, input.ReadBytes().Length);
}
}
+
+ [Test]
+ public void Tag0Throws()
+ {
+ var input = new CodedInputStream(new byte[] { 0 });
+ Assert.Throws<InvalidProtocolBufferException>(() => input.ReadTag());
+ }
}
}
\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs b/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs
index af32917..c1bf7bd 100644
--- a/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs
+++ b/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs
@@ -335,15 +335,16 @@
// Now test Input stream:
{
CodedInputStream cin = new CodedInputStream(new MemoryStream(bytes), new byte[50]);
- uint tag;
Assert.AreEqual(0, cin.Position);
// Field 1:
- Assert.IsTrue(cin.ReadTag(out tag) && tag >> 3 == 1);
+ uint tag = cin.ReadTag();
+ Assert.AreEqual(1, tag >> 3);
Assert.AreEqual(1, cin.Position);
Assert.AreEqual(500, cin.ReadInt32());
Assert.AreEqual(3, cin.Position);
//Field 2:
- Assert.IsTrue(cin.ReadTag(out tag) && tag >> 3 == 2);
+ tag = cin.ReadTag();
+ Assert.AreEqual(2, tag >> 3);
Assert.AreEqual(4, cin.Position);
int childlen = cin.ReadLength();
Assert.AreEqual(120, childlen);
@@ -353,19 +354,22 @@
// Now we are reading child message
{
// Field 11: numeric value: 500
- Assert.IsTrue(cin.ReadTag(out tag) && tag >> 3 == 11);
+ tag = cin.ReadTag();
+ Assert.AreEqual(11, tag >> 3);
Assert.AreEqual(6, cin.Position);
Assert.AreEqual(500, cin.ReadInt32());
Assert.AreEqual(8, cin.Position);
//Field 12: length delimited 120 bytes
- Assert.IsTrue(cin.ReadTag(out tag) && tag >> 3 == 12);
+ tag = cin.ReadTag();
+ Assert.AreEqual(12, tag >> 3);
Assert.AreEqual(9, cin.Position);
ByteString bstr = cin.ReadBytes();
Assert.AreEqual(110, bstr.Length);
Assert.AreEqual((byte) 109, bstr[109]);
Assert.AreEqual(120, cin.Position);
// Field 13: fixed numeric value: 501
- Assert.IsTrue(cin.ReadTag(out tag) && tag >> 3 == 13);
+ tag = cin.ReadTag();
+ Assert.AreEqual(13, tag >> 3);
// ROK - Previously broken here, this returned 126 failing to account for bufferSizeAfterLimit
Assert.AreEqual(121, cin.Position);
Assert.AreEqual(501, cin.ReadSFixed32());
@@ -375,7 +379,8 @@
cin.PopLimit(oldlimit);
Assert.AreEqual(125, cin.Position);
// Field 3: fixed numeric value: 501
- Assert.IsTrue(cin.ReadTag(out tag) && tag >> 3 == 3);
+ tag = cin.ReadTag();
+ Assert.AreEqual(3, tag >> 3);
Assert.AreEqual(126, cin.Position);
Assert.AreEqual(501, cin.ReadSFixed32());
Assert.AreEqual(130, cin.Position);
diff --git a/csharp/src/Google.Protobuf.Test/Collections/RepeatedFieldTest.cs b/csharp/src/Google.Protobuf.Test/Collections/RepeatedFieldTest.cs
index 322100d..8c804fd 100644
--- a/csharp/src/Google.Protobuf.Test/Collections/RepeatedFieldTest.cs
+++ b/csharp/src/Google.Protobuf.Test/Collections/RepeatedFieldTest.cs
@@ -455,7 +455,7 @@
Assert.AreEqual(0, output.SpaceLeft);
CodedInputStream input = new CodedInputStream(bytes);
- Assert.IsTrue(input.ReadTag(out tag));
+ tag = input.ReadTag();
RepeatedField<SampleEnum> values = new RepeatedField<SampleEnum>();
values.AddEntriesFrom(input, FieldCodec.ForEnum(tag, x => (int)x, x => (SampleEnum)x));
@@ -493,7 +493,7 @@
Assert.AreEqual(0, output.SpaceLeft);
CodedInputStream input = new CodedInputStream(bytes);
- Assert.IsTrue(input.ReadTag(out tag));
+ tag = input.ReadTag();
RepeatedField<SampleEnum> values = new RepeatedField<SampleEnum>();
values.AddEntriesFrom(input, FieldCodec.ForEnum(tag, x => (int)x, x => (SampleEnum)x));
diff --git a/csharp/src/Google.Protobuf/CodedInputStream.cs b/csharp/src/Google.Protobuf/CodedInputStream.cs
index 5da03b5..0e2495f 100644
--- a/csharp/src/Google.Protobuf/CodedInputStream.cs
+++ b/csharp/src/Google.Protobuf/CodedInputStream.cs
@@ -254,37 +254,35 @@
#region Reading of tags etc
/// <summary>
- /// Attempts to peek at the next field tag.
+ /// 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 bool PeekNextTag(out uint fieldTag)
+ public uint PeekTag()
{
if (hasNextTag)
{
- fieldTag = nextTag;
- return true;
+ return nextTag;
}
uint savedLast = lastTag;
- hasNextTag = ReadTag(out nextTag);
- lastTag = savedLast;
- fieldTag = nextTag;
- return hasNextTag;
+ nextTag = ReadTag();
+ hasNextTag = true;
+ lastTag = savedLast; // Undo the side effect of ReadTag
+ return nextTag;
}
/// <summary>
- /// Attempts to read a field tag, returning false if we have reached the end
- /// of the input data.
+ /// Reads a field tag, returning the tag of 0 for "end of stream".
/// </summary>
- /// <param name="fieldTag">The 'tag' of the field (id * 8 + wire-format)</param>
- /// <returns>true if the next fieldTag was read</returns>
- public bool ReadTag(out uint fieldTag)
+ /// <returns>The next field tag, or 0 for end of stream. (0 is never a valid tag.)</returns>
+ public uint ReadTag()
{
if (hasNextTag)
{
- fieldTag = nextTag;
- lastTag = fieldTag;
+ lastTag = nextTag;
hasNextTag = false;
- return true;
+ return lastTag;
}
// Optimize for the incredibly common case of having at least two bytes left in the buffer,
@@ -294,7 +292,7 @@
int tmp = buffer[bufferPos++];
if (tmp < 128)
{
- fieldTag = (uint)tmp;
+ lastTag = (uint)tmp;
}
else
{
@@ -302,13 +300,13 @@
if ((tmp = buffer[bufferPos++]) < 128)
{
result |= tmp << 7;
- fieldTag = (uint) result;
+ lastTag = (uint) result;
}
else
{
// Nope, rewind and go the potentially slow route.
bufferPos -= 2;
- fieldTag = ReadRawVarint32();
+ lastTag = ReadRawVarint32();
}
}
}
@@ -316,20 +314,18 @@
{
if (IsAtEnd)
{
- fieldTag = 0;
- lastTag = fieldTag;
- return false;
+ lastTag = 0;
+ return 0; // This is the only case in which we return 0.
}
- fieldTag = ReadRawVarint32();
+ lastTag = ReadRawVarint32();
}
- lastTag = fieldTag;
if (lastTag == 0)
{
// If we actually read zero, that's not a valid tag.
throw InvalidProtocolBufferException.InvalidTag();
}
- return true;
+ return lastTag;
}
/// <summary>
@@ -580,14 +576,10 @@
/// </summary>
public bool MaybeConsumeTag(uint tag)
{
- uint next;
- if (PeekNextTag(out next))
+ if (PeekTag() == tag)
{
- if (next == tag)
- {
- hasNextTag = false;
- return true;
- }
+ hasNextTag = false;
+ return true;
}
return false;
}
diff --git a/csharp/src/Google.Protobuf/Collections/MapField.cs b/csharp/src/Google.Protobuf/Collections/MapField.cs
index fed3d06..5eb2c2f 100644
--- a/csharp/src/Google.Protobuf/Collections/MapField.cs
+++ b/csharp/src/Google.Protobuf/Collections/MapField.cs
@@ -627,12 +627,8 @@
public void MergeFrom(CodedInputStream input)
{
uint tag;
- while (input.ReadTag(out tag))
+ while ((tag = input.ReadTag()) != 0)
{
- if (tag == 0)
- {
- throw InvalidProtocolBufferException.InvalidTag();
- }
if (tag == codec.keyCodec.Tag)
{
Key = codec.keyCodec.Read(input);
diff --git a/csharp/src/Google.Protobuf/FieldCodec.cs b/csharp/src/Google.Protobuf/FieldCodec.cs
index 1076c2a..15d52c7 100644
--- a/csharp/src/Google.Protobuf/FieldCodec.cs
+++ b/csharp/src/Google.Protobuf/FieldCodec.cs
@@ -298,12 +298,8 @@
uint tag;
T value = codec.DefaultValue;
- while (input.ReadTag(out tag))
+ while ((tag = input.ReadTag()) != 0)
{
- if (tag == 0)
- {
- throw InvalidProtocolBufferException.InvalidTag();
- }
if (tag == codec.Tag)
{
value = codec.Read(input);
