* Summary: new Frame type to replace AMQFrame. Instead of holding

	  a shared_ptr to a heap-allocated AMQBody subclass, it holds the
	  body in-line in a boost::variant of all the concrete AMQBody
	  subclasses. Actually there are nested variants, the compiler
	  does not cope well with a single variant of 130-some types.

	  Creating, encoding and decoding a local Frame doess 0 heap
	  allocation apart from that done by the concrete
	  AMQBody::encode/decode - e.g. method bodies with std::string
	  fields.  for method bodies

	  All variants contain type boost::blank. This guarantees 0 heap
	  alloocation by the variant and represents the "uninitialized"
	  state. variant.h provides NoBlankVisitor to help write visitors
	  for variants containing blank. 
	
	* src/qpid/framing/MethodHolder.h, .cpp: Holds a variant
	  containing a method body. 

	* src/qpid/framing/Frame.h, .cpp: New Frame holds body in a
	  variant rather than via heap allocation.

	* src/qpid/framing/variant.h: Utilities for using boost::variant.

	* src/qpid/framing/amqp_types.h: Added FrameType typedef.

	* src/qpid/framing/AMQMethodBody.h: Friends with MethodHolder.

	* src/Makefile.am:
	 - Improved ruby generation rule.
	 - Run method_variants template.
	 - Added new source files
	 - Pre-compiled header rule for method_variants.h

	* rubygen/templates/method_variants.rb: Generate variants
	  to hold methods of each class, and MethodVariant to hold all
	  the class variants.

	* rubygen/cppgen.rb: variant, tuple methods.

	* MethodBodyClass.h.tmpl: Added default constructor to method bodies.

	* amqpgen.rb (AmqpRoot::merge): fix bug in merge.


git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@563683 13f79535-47bb-0310-9956-ffa450edef68

7 files changed, 458 insertions, 0 deletions

diff --git a/cpp/src/qpid/framing/AMQMethodBody.h b/cpp/src/qpid/framing/AMQMethodBody.h
index 2b46c6ea00..cbfd438b48 100644
--- a/cpp/src/qpid/framing/AMQMethodBody.h
+++ b/cpp/src/qpid/framing/AMQMethodBody.h
@@ -80,6 +80,7 @@ class AMQMethodBody : public AMQBody
 
     virtual void printPrefix(std::ostream&) const {}
 
+  friend class MethodHolder;
 };
 
 
diff --git a/cpp/src/qpid/framing/Frame.cpp b/cpp/src/qpid/framing/Frame.cpp
new file mode 100644
index 0000000000..7bdc0adf00
--- /dev/null
+++ b/cpp/src/qpid/framing/Frame.cpp
@@ -0,0 +1,119 @@
+/*
+ *
+ * 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.
+ *
+ */
+#include <boost/format.hpp>
+
+#include "Frame.h"
+#include "qpid/QpidError.h"
+#include "AMQRequestBody.h"
+#include "AMQResponseBody.h"
+
+
+namespace qpid {
+namespace framing {
+
+namespace {
+struct GetBodyVisitor : public NoBlankVisitor<AMQBody*> {
+    QPID_USING_NOBLANK(AMQBody*);
+    AMQBody* operator()(MethodHolder& h) const { return h.getMethod(); }
+    template <class T> AMQBody* operator()(T& t) const { return &t; }
+};
+}
+
+AMQBody* Frame::getBody() {
+    return boost::apply_visitor(GetBodyVisitor(), body);
+}
+
+const AMQBody* Frame::getBody() const {
+    return boost::apply_visitor(GetBodyVisitor(), const_cast<Variant&>(body));
+}
+
+void Frame::encode(Buffer& buffer)
+{
+    buffer.putOctet(getBody()->type());
+    buffer.putShort(channel);    
+    buffer.putLong(getBody()->size());
+    getBody()->encode(buffer);
+    buffer.putOctet(0xCE);
+}
+
+uint32_t Frame::size() const{
+    return 1/*type*/ + 2/*channel*/ + 4/*body size*/ + getBody()->size()
+        + 1/*0xCE*/;
+}
+
+bool Frame::decode(Buffer& buffer)
+{    
+    if(buffer.available() < 7)
+        return false;
+    buffer.record();
+    uint32_t frameSize = decodeHead(buffer);
+    if(buffer.available() < frameSize + 1){
+        buffer.restore();
+        return false;
+    }
+    decodeBody(buffer, frameSize);
+    uint8_t end = buffer.getOctet();
+    if(end != 0xCE) THROW_QPID_ERROR(FRAMING_ERROR, "Frame end not found");
+    return true;
+}
+
+uint32_t Frame::decodeHead(Buffer& buffer){    
+    type = buffer.getOctet();
+    channel = buffer.getShort();
+    return buffer.getLong();
+}
+
+void Frame::decodeBody(Buffer& buffer, uint32_t size)
+{    
+    switch(type)
+    {
+      case METHOD_BODY:
+      case REQUEST_BODY:
+      case RESPONSE_BODY: {
+        ClassId c=buffer.getShort();
+        MethodId m=buffer.getShort();
+        body = MethodHolder(c,m);
+        break;
+      }
+      case HEADER_BODY: 
+	body = AMQHeaderBody();
+	break;
+      case CONTENT_BODY: 
+	body = AMQContentBody();
+	break;
+      case HEARTBEAT_BODY: 
+	body = AMQHeartbeatBody();
+	break;
+      default:
+	THROW_QPID_ERROR(
+            FRAMING_ERROR,
+            boost::format("Unknown frame type %d") % type);
+    }
+    getBody()->decode(buffer, size);
+}
+
+std::ostream& operator<<(std::ostream& out, const Frame& f)
+{
+    return out << "Frame[channel=" << f.getChannel() << "; " << f.body << "]";
+}
+
+
+}} // namespace qpid::framing
diff --git a/cpp/src/qpid/framing/Frame.h b/cpp/src/qpid/framing/Frame.h
new file mode 100644
index 0000000000..4a504a6b41
--- /dev/null
+++ b/cpp/src/qpid/framing/Frame.h
@@ -0,0 +1,72 @@
+#ifndef _AMQFrame_
+#define _AMQFrame_
+
+/*
+ *
+ * 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.
+ *
+ */
+#include "AMQDataBlock.h"
+#include "AMQHeaderBody.h"
+#include "AMQContentBody.h"
+#include "AMQHeartbeatBody.h"
+#include "MethodHolder.h"
+
+namespace qpid {
+namespace framing {
+
+class Frame : public AMQDataBlock {
+  public:
+    typedef boost::variant<boost::blank,
+                           AMQHeaderBody,
+                           AMQContentBody,
+                           AMQHeartbeatBody,
+                           MethodHolder> Variant;
+
+    Frame(ChannelId channel_=0, const Variant& body_=Variant())
+        : body(body_), channel(channel_) {}
+
+    void encode(Buffer& buffer);
+    bool decode(Buffer& buffer); 
+    uint32_t size() const;
+
+    uint16_t getChannel() const { return channel; }
+
+    AMQBody* getBody();
+    const AMQBody* getBody() const;
+
+    template <class T> T* castBody() {
+        return boost::polymorphic_downcast<T*>(getBody());
+    }
+
+    Variant body;
+
+  private:
+    uint32_t decodeHead(Buffer& buffer); 
+    void decodeBody(Buffer& buffer, uint32_t size); 
+
+    uint8_t type;
+    uint16_t channel;
+};
+
+std::ostream& operator<<(std::ostream&, const Frame&);
+
+}} // namespace qpid::framing
+
+
+#endif
diff --git a/cpp/src/qpid/framing/MethodHolder.cpp b/cpp/src/qpid/framing/MethodHolder.cpp
new file mode 100644
index 0000000000..27046af43c
--- /dev/null
+++ b/cpp/src/qpid/framing/MethodHolder.cpp
@@ -0,0 +1,93 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include "MethodHolder.h"
+#include "amqp_types.h"
+#include "qpid/framing/Buffer.h"
+#include "qpid/framing/variant.h"
+
+using namespace boost;
+
+namespace qpid {
+namespace framing {
+
+struct SetVariantVisitor : public NoBlankVisitor<> {
+    QPID_USING_NOBLANK();
+    MethodId id;
+    SetVariantVisitor(MethodId m) : id(m) {}
+    template <class T> void operator()(T& t) const { setVariant(t, id); }
+};
+
+inline void setVariant(MethodVariant& var, ClassId c, MethodId m) {
+    setVariant(var,c);
+    boost::apply_visitor(SetVariantVisitor(m), var);
+}
+
+void MethodHolder::setMethod(ClassId c, MethodId m) {
+    setVariant(method, c, m);
+}
+
+MethodHolder::MethodHolder(ClassId c, MethodId m) {
+    setMethod(c,m);
+}
+
+struct GetClassId : public NoBlankVisitor<ClassId> {
+    QPID_USING_NOBLANK(ClassId);
+    template <class T> ClassId operator()(const T&) const {
+        return T::CLASS_ID;
+    }
+};
+
+struct GetMethodId : public NoBlankVisitor<MethodId> {
+    QPID_USING_NOBLANK(ClassId);
+    template <class T> MethodId operator()(const T&) const {
+        return T::METHOD_ID;
+    }
+};
+
+void MethodHolder::encode(Buffer& b) const {
+    const AMQMethodBody* body = getMethod();
+    b.putShort(body->amqpClassId());
+    b.putShort(body->amqpMethodId());
+    body->encodeContent(b);
+}
+
+void MethodHolder::decode(Buffer& b) {
+    ClassId classId = b.getShort();
+    ClassId methodId = b.getShort();
+    setVariant(method, classId, methodId);
+    getMethod()->decodeContent(b);
+}
+
+uint32_t  MethodHolder::size() const {
+    return sizeof(ClassId)+sizeof(MethodId)+getMethod()->size();
+}
+
+
+AMQMethodBody* MethodHolder::getMethod() {
+    return applyApplyVisitor(AddressVisitor<AMQMethodBody*>(), method);
+}
+
+const AMQMethodBody* MethodHolder::getMethod() const {
+    return const_cast<MethodHolder*>(this)->getMethod();
+}
+
+}} // namespace qpid::framing
diff --git a/cpp/src/qpid/framing/MethodHolder.h b/cpp/src/qpid/framing/MethodHolder.h
new file mode 100644
index 0000000000..b93c6b83b1
--- /dev/null
+++ b/cpp/src/qpid/framing/MethodHolder.h
@@ -0,0 +1,80 @@
+#ifndef QPID_FRAMING_METHODBODYHOLDER_H
+#define QPID_FRAMING_METHODBODYHOLDER_H
+
+/*
+ *
+ * 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.
+ *
+ */
+
+#include "qpid/framing/method_variants.h"
+
+#include <boost/type_traits/has_nothrow_copy.hpp>
+
+namespace qpid {
+namespace framing {
+
+class AMQMethodBody;
+
+/**
+ * Holder for arbitrary method body.
+ */
+class MethodHolder
+{
+  public:
+    MethodHolder() {}
+    MethodHolder(const MethodVariant& mv) : method(mv) {}
+
+    /** Construct from a concrete method body type.
+     * ClassVariant<T>::value is the containing class variant.
+     */
+    template <class T>
+    MethodHolder(const T& t)
+        : method(typename ClassVariant<T>::value(t)) {}
+
+    /** Construct from class/method ID, set the method accordingly. */
+    MethodHolder(ClassId, MethodId);
+
+    /** Set the method to the type corresponding to ClassId, MethodId */
+    void setMethod(ClassId, MethodId);
+    
+    AMQMethodBody* getMethod();
+    const AMQMethodBody* getMethod() const;
+    
+    MethodVariant method;
+
+    void encode(Buffer&) const;
+    void decode(Buffer&);
+    uint32_t size() const;
+};
+
+inline std::ostream& operator<<(std::ostream& out, const MethodHolder& h) {
+    return out << h.method;
+}
+
+
+}} // namespace qpid::framing
+
+namespace boost {
+template<> struct has_nothrow_copy<qpid::framing::MethodHolder> 
+    : public boost::true_type {};
+}
+
+
+
+#endif  /*!QPID_FRAMING_METHODBODYHOLDER_H*/
diff --git a/cpp/src/qpid/framing/amqp_types.h b/cpp/src/qpid/framing/amqp_types.h
index ff75b28468..5ea08a69af 100644
--- a/cpp/src/qpid/framing/amqp_types.h
+++ b/cpp/src/qpid/framing/amqp_types.h
@@ -42,6 +42,7 @@ namespace qpid {
 namespace framing {
 
 using std::string;
+typedef uint8_t FrameType;
 typedef uint16_t ChannelId;
 typedef uint64_t RequestId;
 typedef uint64_t ResponseId;
diff --git a/cpp/src/qpid/framing/variant.h b/cpp/src/qpid/framing/variant.h
new file mode 100644
index 0000000000..3cb8aece5d
--- /dev/null
+++ b/cpp/src/qpid/framing/variant.h
@@ -0,0 +1,92 @@
+#ifndef QPID_FRAMING_VARIANT_H
+#define QPID_FRAMING_VARIANT_H
+
+/*
+ * 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.
+ *
+ */
+
+/**@file Tools for using boost::variant */
+
+#include "qpid/QpidError.h"
+
+#include <boost/variant.hpp>
+
+namespace qpid {
+namespace framing {
+class Buffer;
+
+/** boost::static_visitor that throws exception if variant contains blank.
+ * Sublclasses need to have a using() declaration, can be generated
+ * with QPID_USING_BLANK_THROW(R)
+ */
+template <class R=void>
+struct NoBlankVisitor : public boost::static_visitor<R> {
+    R foundBlank() const {
+        assert(0);
+        THROW_QPID_ERROR(INTERNAL_ERROR, "Invalid variant value.");
+    }
+    R operator()(const boost::blank&) const { return foundBlank(); }
+    R operator()(boost::blank&) const { return foundBlank(); }
+};
+
+
+}} // qpid::framing
+
+
+/** Generate using statement needed in visitors inheriting NoBlankVisitor
+ *  @param R return type.
+ */
+#define QPID_USING_NOBLANK(R) using ::qpid::framing::NoBlankVisitor<R>::operator()
+
+namespace qpid {
+namespace framing {
+
+/** Convert the variant value to type R. */
+template <class R> struct ConvertVisitor : public NoBlankVisitor<R> {
+    QPID_USING_NOBLANK(R);
+    template <class T> R operator()(T& t) const { return t; }
+};
+
+/** Convert address of variant value to type R. */
+template <class R> struct AddressVisitor : public NoBlankVisitor<R> {
+    QPID_USING_NOBLANK(R);
+    template <class T> R operator()(T& t) const { return &t; }
+};
+
+/** Apply a visitor to the nested variant in a variant of variants */
+template<class V>
+struct ApplyVisitor : public NoBlankVisitor<typename V::result_type> {
+    QPID_USING_NOBLANK(typename V::result_type);
+    const V& visitor;
+    ApplyVisitor(const V& v) : visitor(v) {}
+    template <class T> typename V::result_type operator()(T& t) const {
+        return boost::apply_visitor(visitor, t);
+    }
+};
+
+/** Convenience function to construct and apply an ApplyVisitor */
+template <class Visitor, class Visitable>
+typename Visitor::result_type applyApplyVisitor(const Visitor& visitor, Visitable& visitable) {
+    return boost::apply_visitor(ApplyVisitor<Visitor>(visitor), visitable);
+}
+
+}} // namespace qpid::framing
+
+    
+#endif  /*!QPID_FRAMING_VARIANT_H*/