THRIFT-922. cpp: Convert protocol classes to use non-virtual functions

Updated the thrift protocol classes to use non-virtual calls for most
functions.  The correct implementation is determined at compile time via
templates now.  Only the base TProtocol class falls back to using
virtual function calls.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@1005135 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/cpp/src/protocol/TVirtualProtocol.h b/lib/cpp/src/protocol/TVirtualProtocol.h
new file mode 100644
index 0000000..7f01570
--- /dev/null
+++ b/lib/cpp/src/protocol/TVirtualProtocol.h
@@ -0,0 +1,495 @@
+/*
+ * 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.
+ */
+
+#ifndef _THRIFT_PROTOCOL_TVIRTUALPROTOCOL_H_
+#define _THRIFT_PROTOCOL_TVIRTUALPROTOCOL_H_ 1
+
+#include <protocol/TProtocol.h>
+
+namespace apache { namespace thrift { namespace protocol {
+
+using apache::thrift::transport::TTransport;
+
+/**
+ * Helper class that provides default implementations of TProtocol methods.
+ *
+ * This class provides default implementations of the non-virtual TProtocol
+ * methods.  It exists primarily so TVirtualProtocol can derive from it.  It
+ * prevents TVirtualProtocol methods from causing infinite recursion if the
+ * non-virtual methods are not overridden by the TVirtualProtocol subclass.
+ *
+ * You probably don't want to use this class directly.  Use TVirtualProtocol
+ * instead.
+ */
+class TProtocolDefaults : public TProtocol {
+ public:
+  uint32_t readMessageBegin(std::string& name,
+                            TMessageType& messageType,
+                            int32_t& seqid) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readMessageEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readStructBegin(std::string& name) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readStructEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readFieldBegin(std::string& name,
+                          TType& fieldType,
+                          int16_t& fieldId) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readFieldEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readMapBegin(TType& keyType, TType& valType, uint32_t& size) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readMapEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readListBegin(TType& elemType, uint32_t& size) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readListEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readSetBegin(TType& elemType, uint32_t& size) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readSetEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readBool(bool& value) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readByte(int8_t& byte) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readI16(int16_t& i16) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readI32(int32_t& i32) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readI64(int64_t& i64) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readDouble(double& dub) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readString(std::string& str) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t readBinary(std::string& str) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support reading (yet).");
+  }
+
+  uint32_t writeMessageBegin(const std::string& name,
+                             const TMessageType messageType,
+                             const int32_t seqid) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeMessageEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+
+  uint32_t writeStructBegin(const char* name) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeStructEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeFieldBegin(const char* name,
+                           const TType fieldType,
+                           const int16_t fieldId) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeFieldEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeFieldStop() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeMapBegin(const TType keyType,
+                         const TType valType,
+                         const uint32_t size) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeMapEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeListBegin(const TType elemType, const uint32_t size) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeListEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeSetBegin(const TType elemType, const uint32_t size) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeSetEnd() {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeBool(const bool value) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeByte(const int8_t byte) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeI16(const int16_t i16) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeI32(const int32_t i32) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeI64(const int64_t i64) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeDouble(const double dub) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeString(const std::string& str) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t writeBinary(const std::string& str) {
+    throw TProtocolException(TProtocolException::NOT_IMPLEMENTED,
+                             "this protocol does not support writing (yet).");
+  }
+
+  uint32_t skip(TType type) {
+    return ::apache::thrift::protocol::skip(*this, type);
+  }
+
+ protected:
+  TProtocolDefaults(boost::shared_ptr<TTransport> ptrans)
+    : TProtocol(ptrans)
+  {}
+};
+
+/**
+ * Concrete TProtocol classes should inherit from TVirtualProtocol
+ * so they don't have to manually override virtual methods.
+ */
+template <class Protocol_, class Super_=TProtocolDefaults>
+class TVirtualProtocol : public Super_ {
+ public:
+  /**
+   * Writing functions.
+   */
+
+  virtual uint32_t writeMessageBegin_virt(const std::string& name,
+                                          const TMessageType messageType,
+                                          const int32_t seqid) {
+    return static_cast<Protocol_*>(this)->writeMessageBegin(name, messageType,
+                                                            seqid);
+  }
+
+  virtual uint32_t writeMessageEnd_virt() {
+    return static_cast<Protocol_*>(this)->writeMessageEnd();
+  }
+
+
+  virtual uint32_t writeStructBegin_virt(const char* name) {
+    return static_cast<Protocol_*>(this)->writeStructBegin(name);
+  }
+
+  virtual uint32_t writeStructEnd_virt() {
+    return static_cast<Protocol_*>(this)->writeStructEnd();
+  }
+
+  virtual uint32_t writeFieldBegin_virt(const char* name,
+                                        const TType fieldType,
+                                        const int16_t fieldId) {
+    return static_cast<Protocol_*>(this)->writeFieldBegin(name, fieldType,
+                                                          fieldId);
+  }
+
+  virtual uint32_t writeFieldEnd_virt() {
+    return static_cast<Protocol_*>(this)->writeFieldEnd();
+  }
+
+  virtual uint32_t writeFieldStop_virt() {
+    return static_cast<Protocol_*>(this)->writeFieldStop();
+  }
+
+  virtual uint32_t writeMapBegin_virt(const TType keyType,
+                                      const TType valType,
+                                      const uint32_t size) {
+    return static_cast<Protocol_*>(this)->writeMapBegin(keyType, valType, size);
+  }
+
+  virtual uint32_t writeMapEnd_virt() {
+    return static_cast<Protocol_*>(this)->writeMapEnd();
+  }
+
+  virtual uint32_t writeListBegin_virt(const TType elemType,
+                                       const uint32_t size) {
+    return static_cast<Protocol_*>(this)->writeListBegin(elemType, size);
+  }
+
+  virtual uint32_t writeListEnd_virt() {
+    return static_cast<Protocol_*>(this)->writeListEnd();
+  }
+
+  virtual uint32_t writeSetBegin_virt(const TType elemType,
+                                      const uint32_t size) {
+    return static_cast<Protocol_*>(this)->writeSetBegin(elemType, size);
+  }
+
+  virtual uint32_t writeSetEnd_virt() {
+    return static_cast<Protocol_*>(this)->writeSetEnd();
+  }
+
+  virtual uint32_t writeBool_virt(const bool value) {
+    return static_cast<Protocol_*>(this)->writeBool(value);
+  }
+
+  virtual uint32_t writeByte_virt(const int8_t byte) {
+    return static_cast<Protocol_*>(this)->writeByte(byte);
+  }
+
+  virtual uint32_t writeI16_virt(const int16_t i16) {
+    return static_cast<Protocol_*>(this)->writeI16(i16);
+  }
+
+  virtual uint32_t writeI32_virt(const int32_t i32) {
+    return static_cast<Protocol_*>(this)->writeI32(i32);
+  }
+
+  virtual uint32_t writeI64_virt(const int64_t i64) {
+    return static_cast<Protocol_*>(this)->writeI64(i64);
+  }
+
+  virtual uint32_t writeDouble_virt(const double dub) {
+    return static_cast<Protocol_*>(this)->writeDouble(dub);
+  }
+
+  virtual uint32_t writeString_virt(const std::string& str) {
+    return static_cast<Protocol_*>(this)->writeString(str);
+  }
+
+  virtual uint32_t writeBinary_virt(const std::string& str) {
+    return static_cast<Protocol_*>(this)->writeBinary(str);
+  }
+
+  /**
+   * Reading functions
+   */
+
+  virtual uint32_t readMessageBegin_virt(std::string& name,
+                                         TMessageType& messageType,
+                                         int32_t& seqid) {
+    return static_cast<Protocol_*>(this)->readMessageBegin(name, messageType,
+                                                           seqid);
+  }
+
+  virtual uint32_t readMessageEnd_virt() {
+    return static_cast<Protocol_*>(this)->readMessageEnd();
+  }
+
+  virtual uint32_t readStructBegin_virt(std::string& name) {
+    return static_cast<Protocol_*>(this)->readStructBegin(name);
+  }
+
+  virtual uint32_t readStructEnd_virt() {
+    return static_cast<Protocol_*>(this)->readStructEnd();
+  }
+
+  virtual uint32_t readFieldBegin_virt(std::string& name,
+                                       TType& fieldType,
+                                       int16_t& fieldId) {
+    return static_cast<Protocol_*>(this)->readFieldBegin(name, fieldType,
+                                                         fieldId);
+  }
+
+  virtual uint32_t readFieldEnd_virt() {
+    return static_cast<Protocol_*>(this)->readFieldEnd();
+  }
+
+  virtual uint32_t readMapBegin_virt(TType& keyType,
+                                     TType& valType,
+                                     uint32_t& size) {
+    return static_cast<Protocol_*>(this)->readMapBegin(keyType, valType, size);
+  }
+
+  virtual uint32_t readMapEnd_virt() {
+    return static_cast<Protocol_*>(this)->readMapEnd();
+  }
+
+  virtual uint32_t readListBegin_virt(TType& elemType,
+                                      uint32_t& size) {
+    return static_cast<Protocol_*>(this)->readListBegin(elemType, size);
+  }
+
+  virtual uint32_t readListEnd_virt() {
+    return static_cast<Protocol_*>(this)->readListEnd();
+  }
+
+  virtual uint32_t readSetBegin_virt(TType& elemType,
+                                     uint32_t& size) {
+    return static_cast<Protocol_*>(this)->readSetBegin(elemType, size);
+  }
+
+  virtual uint32_t readSetEnd_virt() {
+    return static_cast<Protocol_*>(this)->readSetEnd();
+  }
+
+  virtual uint32_t readBool_virt(bool& value) {
+    return static_cast<Protocol_*>(this)->readBool(value);
+  }
+
+  virtual uint32_t readByte_virt(int8_t& byte) {
+    return static_cast<Protocol_*>(this)->readByte(byte);
+  }
+
+  virtual uint32_t readI16_virt(int16_t& i16) {
+    return static_cast<Protocol_*>(this)->readI16(i16);
+  }
+
+  virtual uint32_t readI32_virt(int32_t& i32) {
+    return static_cast<Protocol_*>(this)->readI32(i32);
+  }
+
+  virtual uint32_t readI64_virt(int64_t& i64) {
+    return static_cast<Protocol_*>(this)->readI64(i64);
+  }
+
+  virtual uint32_t readDouble_virt(double& dub) {
+    return static_cast<Protocol_*>(this)->readDouble(dub);
+  }
+
+  virtual uint32_t readString_virt(std::string& str) {
+    return static_cast<Protocol_*>(this)->readString(str);
+  }
+
+  virtual uint32_t readBinary_virt(std::string& str) {
+    return static_cast<Protocol_*>(this)->readBinary(str);
+  }
+
+  virtual uint32_t skip_virt(TType type) {
+    return static_cast<Protocol_*>(this)->skip(type);
+  }
+
+  /*
+   * Provide a default skip() implementation that uses non-virtual read
+   * methods.
+   *
+   * Note: subclasses that use TVirtualProtocol to derive from another protocol
+   * implementation (i.e., not TProtocolDefaults) should beware that this may
+   * override any non-default skip() implementation provided by the parent
+   * transport class.  They may need to explicitly redefine skip() to call the
+   * correct parent implementation, if desired.
+   */
+  uint32_t skip(TType type) {
+    Protocol_* const prot = static_cast<Protocol_*>(this);
+    return ::apache::thrift::protocol::skip(*prot, type);
+  }
+
+ protected:
+  TVirtualProtocol(boost::shared_ptr<TTransport> ptrans)
+    : Super_(ptrans)
+  {}
+};
+
+}}} // apache::thrift::protocol
+
+#endif // #define _THRIFT_PROTOCOL_TVIRTUALPROTOCOL_H_ 1