From ff334a60eb2e74722867dd41b78d7c8c90bc8d0c Mon Sep 17 00:00:00 2001 From: Jon Skeet Date: Wed, 5 Aug 2015 11:23:38 +0100 Subject: [PATCH] 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. --- .../CodedInputStreamExtensions.cs | 3 +- .../CodedInputStreamTest.cs | 20 ++++--- .../CodedOutputStreamTest.cs | 19 ++++--- .../Collections/RepeatedFieldTest.cs | 4 +- .../src/Google.Protobuf/CodedInputStream.cs | 56 ++++++++----------- .../Google.Protobuf/Collections/MapField.cs | 6 +- csharp/src/Google.Protobuf/FieldCodec.cs | 6 +- .../compiler/csharp/csharp_message.cc | 4 +- 8 files changed, 53 insertions(+), 65 deletions(-) diff --git a/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs b/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs index 408c7cb90a..23af28870a 100644 --- a/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs +++ b/csharp/src/Google.Protobuf.Test/CodedInputStreamExtensions.cs @@ -38,8 +38,7 @@ namespace Google.Protobuf { 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 6e25fa37e8..c4c92efd37 100644 --- a/csharp/src/Google.Protobuf.Test/CodedInputStreamTest.cs +++ b/csharp/src/Google.Protobuf.Test/CodedInputStreamTest.cs @@ -279,9 +279,7 @@ namespace Google.Protobuf 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(() => input.ReadBytes()); @@ -377,9 +375,7 @@ namespace Google.Protobuf 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 @@ namespace Google.Protobuf 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(() => 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 af3291748a..c1bf7bd638 100644 --- a/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs +++ b/csharp/src/Google.Protobuf.Test/CodedOutputStreamTest.cs @@ -335,15 +335,16 @@ namespace Google.Protobuf // 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 @@ namespace Google.Protobuf // 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 @@ namespace Google.Protobuf 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 322100d04b..8c804fdd22 100644 --- a/csharp/src/Google.Protobuf.Test/Collections/RepeatedFieldTest.cs +++ b/csharp/src/Google.Protobuf.Test/Collections/RepeatedFieldTest.cs @@ -455,7 +455,7 @@ namespace Google.Protobuf.Collections Assert.AreEqual(0, output.SpaceLeft); CodedInputStream input = new CodedInputStream(bytes); - Assert.IsTrue(input.ReadTag(out tag)); + tag = input.ReadTag(); RepeatedField values = new RepeatedField(); values.AddEntriesFrom(input, FieldCodec.ForEnum(tag, x => (int)x, x => (SampleEnum)x)); @@ -493,7 +493,7 @@ namespace Google.Protobuf.Collections Assert.AreEqual(0, output.SpaceLeft); CodedInputStream input = new CodedInputStream(bytes); - Assert.IsTrue(input.ReadTag(out tag)); + tag = input.ReadTag(); RepeatedField values = new RepeatedField(); 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 5da03b5c53..0e2495f1d9 100644 --- a/csharp/src/Google.Protobuf/CodedInputStream.cs +++ b/csharp/src/Google.Protobuf/CodedInputStream.cs @@ -254,37 +254,35 @@ namespace Google.Protobuf #region Reading of tags etc /// - /// Attempts to peek at the next field tag. + /// Peeks at the next field tag. This is like calling , but the + /// tag is not consumed. (So a subsequent call to will return the + /// same value.) /// - 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; } /// - /// 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". /// - /// The 'tag' of the field (id * 8 + wire-format) - /// true if the next fieldTag was read - public bool ReadTag(out uint fieldTag) + /// The next field tag, or 0 for end of stream. (0 is never a valid tag.) + 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 @@ namespace Google.Protobuf int tmp = buffer[bufferPos++]; if (tmp < 128) { - fieldTag = (uint)tmp; + lastTag = (uint)tmp; } else { @@ -302,13 +300,13 @@ namespace Google.Protobuf 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 @@ namespace Google.Protobuf { 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; } /// @@ -580,14 +576,10 @@ namespace Google.Protobuf /// 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 fed3d06217..5eb2c2fcbb 100644 --- a/csharp/src/Google.Protobuf/Collections/MapField.cs +++ b/csharp/src/Google.Protobuf/Collections/MapField.cs @@ -627,12 +627,8 @@ namespace Google.Protobuf.Collections 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 1076c2a94e..15d52c7d5c 100644 --- a/csharp/src/Google.Protobuf/FieldCodec.cs +++ b/csharp/src/Google.Protobuf/FieldCodec.cs @@ -298,12 +298,8 @@ namespace Google.Protobuf 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); diff --git a/src/google/protobuf/compiler/csharp/csharp_message.cc b/src/google/protobuf/compiler/csharp/csharp_message.cc index ea722455d1..40c13de5b8 100644 --- a/src/google/protobuf/compiler/csharp/csharp_message.cc +++ b/src/google/protobuf/compiler/csharp/csharp_message.cc @@ -417,13 +417,11 @@ void MessageGenerator::GenerateMergingMethods(io::Printer* printer) { printer->Indent(); printer->Print( "uint tag;\n" - "while (input.ReadTag(out tag)) {\n" + "while ((tag = input.ReadTag()) != 0) {\n" " switch(tag) {\n"); printer->Indent(); printer->Indent(); printer->Print( - "case 0:\n" // 0 signals EOF / limit reached - " throw pb::InvalidProtocolBufferException.InvalidTag();\n" "default:\n" " if (pb::WireFormat.IsEndGroupTag(tag)) {\n" " return;\n"