Author: bryanduxbury
Date: Tue Oct 19 23:00:27 2010
New Revision: 1024455
URL: http://svn.apache.org/viewvc?rev=1024455&view=rev
Log:
THRIFT-947. java: Provide a helper method to determine the TProtocol used to
serialize some data.
Patch: Mathias Herberts
Added:
incubator/thrift/trunk/lib/java/test/org/apache/thrift/protocol/TestTProtocolUtil.java
Modified:
incubator/thrift/trunk/lib/java/src/org/apache/thrift/protocol/TProtocolUtil.java
incubator/thrift/trunk/test/ThriftTest.thrift
Modified:
incubator/thrift/trunk/lib/java/src/org/apache/thrift/protocol/TProtocolUtil.java
URL:
http://svn.apache.org/viewvc/incubator/thrift/trunk/lib/java/src/org/apache/thrift/protocol/TProtocolUtil.java?rev=1024455&r1=1024454&r2=1024455&view=diff
==============================================================================
---
incubator/thrift/trunk/lib/java/src/org/apache/thrift/protocol/TProtocolUtil.java
(original)
+++
incubator/thrift/trunk/lib/java/src/org/apache/thrift/protocol/TProtocolUtil.java
Tue Oct 19 23:00:27 2010
@@ -155,4 +155,77 @@ public class TProtocolUtil {
break;
}
}
+
+ /**
+ * Attempt to determine the protocol used to serialize some data.
+ *
+ * The guess is based on known specificities of supported protocols.
+ * In some cases, no guess can be done, in that case we return the
+ * fallback TProtocolFactory.
+ * To be certain to correctly detect the protocol, the first encoded
+ * field should have a field id < 256
+ *
+ * @param data The serialized data to guess the protocol for.
+ * @param fallback The TProtocol to return if no guess can be made.
+ * @return a Class implementing TProtocolFactory which can be used to create
a deserializer.
+ */
+ public static TProtocolFactory guessProtocolFactory(byte[] data,
TProtocolFactory fallback) {
+ //
+ // If the first and last bytes are opening/closing curly braces we guess
the protocol as
+ // being TJSONProtocol.
+ // It could not be a TCompactBinary encoding for a field of type 0xb (Map)
+ // with delta id 7 as the last byte for TCompactBinary is always 0.
+ //
+
+ if ('{' == data[0] && '}' == data[data.length - 1]) {
+ return new TJSONProtocol.Factory();
+ }
+
+ //
+ // If the last byte is not 0, then it cannot be TCompactProtocol, it must
be
+ // TBinaryProtocol.
+ //
+
+ if (data[data.length - 1] != 0) {
+ return new TBinaryProtocol.Factory();
+ }
+
+ //
+ // A first byte of value > 16 indicates TCompactProtocol was used, and the
first byte
+ // encodes a delta field id (id <= 15) and a field type.
+ //
+
+ if (data[0] > 0x10) {
+ return new TCompactProtocol.Factory();
+ }
+
+ //
+ // If the second byte is 0 then it is a field id < 256 encoded by
TBinaryProtocol.
+ // It cannot possibly be TCompactProtocol since a value of 0 would imply a
field id
+ // of 0 as the zig zag varint encoding would end.
+ //
+
+ if (data.length > 1 && 0 == data[1]) {
+ return new TBinaryProtocol.Factory();
+ }
+
+ //
+ // If bit 7 of the first byte of the field id is set then we have two
choices:
+ // 1. A field id > 63 was encoded with TCompactProtocol.
+ // 2. A field id > 0x7fff (32767) was encoded with TBinaryProtocol and the
last byte of the
+ // serialized data is 0.
+ // Option 2 is impossible since field ids are short and thus limited to
32767.
+ //
+
+ if (data.length > 1 && (data[1] & 0x80) != 0) {
+ return new TCompactProtocol.Factory();
+ }
+
+ //
+ // The remaining case is either a field id <= 63 encoded as
TCompactProtocol,
+ // one >= 256 encoded with TBinaryProtocol with a last byte at 0, or an
empty structure.
+ // As we cannot really decide, we return the fallback protocol.
+ //
+ return fallback;
+ }
}
Added:
incubator/thrift/trunk/lib/java/test/org/apache/thrift/protocol/TestTProtocolUtil.java
URL:
http://svn.apache.org/viewvc/incubator/thrift/trunk/lib/java/test/org/apache/thrift/protocol/TestTProtocolUtil.java?rev=1024455&view=auto
==============================================================================
---
incubator/thrift/trunk/lib/java/test/org/apache/thrift/protocol/TestTProtocolUtil.java
(added)
+++
incubator/thrift/trunk/lib/java/test/org/apache/thrift/protocol/TestTProtocolUtil.java
Tue Oct 19 23:00:27 2010
@@ -0,0 +1,97 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.thrift.protocol;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.List;
+
+import junit.framework.TestCase;
+
+import org.apache.thrift.Fixtures;
+import org.apache.thrift.TBase;
+import org.apache.thrift.TDeserializer;
+import org.apache.thrift.TException;
+import org.apache.thrift.TSerializer;
+import org.apache.thrift.transport.TMemoryBuffer;
+
+import thrift.test.CompactProtoTestStruct;
+import thrift.test.HolyMoley;
+import thrift.test.Nesting;
+import thrift.test.OneOfEach;
+import thrift.test.Srv;
+import thrift.test.GuessProtocolStruct;
+
+public class TestTProtocolUtil extends TestCase {
+
+ public void testGuessProtocolFactory_JSON() throws Exception {
+
+ byte[] data = "{foo}".getBytes();
+ TProtocolFactory factory = TProtocolUtil.guessProtocolFactory(data, new
TCompactProtocol.Factory());
+ assertTrue(factory instanceof TJSONProtocol.Factory);
+
+ // Make sure data serialized with TCompact and which starts with '{'
+ // is not mistakenly guessed as serialized with JSON.
+
+ GuessProtocolStruct s = new GuessProtocolStruct();
+ s.putToMap_field("}","}");
+ byte[] ser = new TSerializer(new TCompactProtocol.Factory()).serialize(s);
+ factory = TProtocolUtil.guessProtocolFactory(ser, new
TCompactProtocol.Factory());
+ assertFalse(factory instanceof TJSONProtocol.Factory);
+ }
+
+ public void testGuessProtocolFactory_Binary() throws Exception {
+ // Check that a last byte != 0 is correctly reported as Binary
+
+ byte[] buf = new byte[1];
+ for (int i = 1; i < 256; i++) {
+ buf[0] = (byte) i;
+ TProtocolFactory factory = TProtocolUtil.guessProtocolFactory(buf, new
TCompactProtocol.Factory());
+ assertTrue(factory instanceof TBinaryProtocol.Factory);
+ }
+
+ // Check that a second byte set to 0 is reported as Binary
+ buf = new byte[2];
+ TProtocolFactory factory = TProtocolUtil.guessProtocolFactory(buf, new
TCompactProtocol.Factory());
+ assertTrue(factory instanceof TBinaryProtocol.Factory);
+ }
+
+ public void testGuessProtocolFactory_Compact() throws Exception {
+ // Check that a first byte > 0x10 is reported as Compact
+ byte[] buf = new byte[3];
+ buf[0] = 0x11;
+ TProtocolFactory factory = TProtocolUtil.guessProtocolFactory(buf, new
TBinaryProtocol.Factory());
+ assertTrue(factory instanceof TCompactProtocol.Factory);
+
+ // Check that second byte >= 0x80 is reported as Compact
+ buf[0] = 0;
+ for (int i = 0x80; i < 0x100; i++) {
+ buf[1] = (byte) i;
+ factory = TProtocolUtil.guessProtocolFactory(buf, new
TBinaryProtocol.Factory());
+ assertTrue(factory instanceof TCompactProtocol.Factory);
+ }
+ }
+
+ public void testGuessProtocolFactory_Undecided() throws Exception {
+ byte[] buf = new byte[3];
+ buf[1] = 0x7e;
+ TProtocolFactory factory = TProtocolUtil.guessProtocolFactory(buf, new
TSimpleJSONProtocol.Factory());
+ assertTrue(factory instanceof TSimpleJSONProtocol.Factory);
+ }
+}
Modified: incubator/thrift/trunk/test/ThriftTest.thrift
URL:
http://svn.apache.org/viewvc/incubator/thrift/trunk/test/ThriftTest.thrift?rev=1024455&r1=1024454&r2=1024455&view=diff
==============================================================================
--- incubator/thrift/trunk/test/ThriftTest.thrift (original)
+++ incubator/thrift/trunk/test/ThriftTest.thrift Tue Oct 19 23:00:27 2010
@@ -187,3 +187,7 @@ struct ListTypeVersioningV2 {
1: list<string> strings;
2: string hello;
}
+
+struct GuessProtocolStruct {
+ 7: map<string,string> map_field,
+}
