* 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

1 files changed, 119 insertions, 0 deletions

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