Cluster multicasts buffers rather than frames.

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@691489 13f79535-47bb-0310-9956-ffa450edef68

5 files changed, 123 insertions, 0 deletions

diff --git a/cpp/src/qpid/framing/AMQFrame.cpp b/cpp/src/qpid/framing/AMQFrame.cpp
index c1fc647b52..662b3574ff 100644
--- a/cpp/src/qpid/framing/AMQFrame.cpp
+++ b/cpp/src/qpid/framing/AMQFrame.cpp
@@ -45,6 +45,13 @@ uint32_t AMQFrame::frameOverhead() {
     return 12 /*frame header*/;
 }
 
+uint16_t AMQFrame::DECODE_SIZE_MIN=4;
+
+uint16_t AMQFrame::decodeSize(char* data) {
+    Buffer buf(data+2, DECODE_SIZE_MIN);
+    return buf.getShort();
+}
+
 void AMQFrame::encode(Buffer& buffer) const
 {
     //set track first (controls on track 0, everything else on 1):
diff --git a/cpp/src/qpid/framing/AMQFrame.h b/cpp/src/qpid/framing/AMQFrame.h
index 5a8e55f9d2..331a57e08d 100644
--- a/cpp/src/qpid/framing/AMQFrame.h
+++ b/cpp/src/qpid/framing/AMQFrame.h
@@ -104,7 +104,10 @@ class AMQFrame : public AMQDataBlock
     bool getEos() const { return eos; }
     void setEos(bool isEos) { eos = isEos; }
 
+    static uint16_t DECODE_SIZE_MIN;
     static uint32_t frameOverhead();
+    /** Must point to at least DECODE_SIZE_MIN bytes of data */
+    static uint16_t decodeSize(char* data);
   private:
     void init() { bof = eof = bos = eos = true; subchannel=0; channel=0; }
 
diff --git a/cpp/src/qpid/framing/Buffer.h b/cpp/src/qpid/framing/Buffer.h
index a27b15cac0..4f482dc206 100644
--- a/cpp/src/qpid/framing/Buffer.h
+++ b/cpp/src/qpid/framing/Buffer.h
@@ -74,6 +74,7 @@ class Buffer
     uint32_t getSize() { return size; }
     uint32_t getPosition() { return position; }
     Iterator getIterator() { return Iterator(*this); }
+    char* getPointer() { return data; }
         
     void putOctet(uint8_t i);
     void putShort(uint16_t i);
diff --git a/cpp/src/qpid/framing/FrameDecoder.cpp b/cpp/src/qpid/framing/FrameDecoder.cpp
new file mode 100644
index 0000000000..07e2f7513d
--- /dev/null
+++ b/cpp/src/qpid/framing/FrameDecoder.cpp
@@ -0,0 +1,68 @@
+/*
+ *
+ * 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 "FrameDecoder.h"
+#include "Buffer.h"
+#include "qpid/log/Statement.h"
+#include <algorithm>
+
+namespace qpid {
+namespace framing {
+
+namespace {
+/** Move up to n bytes from start of buf to end of bytes. */
+void move(std::vector<char>& bytes, Buffer& buffer, size_t n) {
+    size_t oldSize = bytes.size();
+    n = std::min(n, size_t(buffer.available()));
+    bytes.resize(oldSize+n);
+    char* p = &bytes[oldSize];
+    buffer.getRawData(reinterpret_cast<uint8_t*>(p), n);
+}
+}
+
+bool FrameDecoder::decode(Buffer& buffer) {
+    if (buffer.available() == 0) return false;
+    if (fragment.empty()) {     
+        if (frame.decode(buffer)) // Decode from buffer
+            return true;
+        else                    // Store fragment
+            move(fragment, buffer, buffer.available());
+    }
+    else {                      // Already have a fragment
+        // Get enough data to decode the frame size.
+        if (fragment.size() < AMQFrame::DECODE_SIZE_MIN) {
+            move(fragment, buffer, AMQFrame::DECODE_SIZE_MIN - fragment.size());
+        }
+        if (fragment.size() >= AMQFrame::DECODE_SIZE_MIN) {
+            uint16_t size = AMQFrame::decodeSize(&fragment[0]);
+            assert(size > fragment.size());
+            move(fragment, buffer, size-fragment.size());
+            Buffer b(&fragment[0], fragment.size());
+            if (frame.decode(b)) {
+                assert(b.available() == 0);
+                fragment.clear();
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+}} // namespace qpid::framing
diff --git a/cpp/src/qpid/framing/FrameDecoder.h b/cpp/src/qpid/framing/FrameDecoder.h
new file mode 100644
index 0000000000..7f974dadc3
--- /dev/null
+++ b/cpp/src/qpid/framing/FrameDecoder.h
@@ -0,0 +1,44 @@
+#ifndef QPID_FRAMING_FRAMEDECODER_H
+#define QPID_FRAMING_FRAMEDECODER_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 "AMQFrame.h"
+
+namespace qpid {
+namespace framing {
+
+/**
+ * Decode a frame from buffer.  If buffer does not contain a complete
+ * frame, caches the fragment for the next call to decode.
+ */
+class FrameDecoder
+{
+  public:
+    bool decode(Buffer& buffer);
+    AMQFrame frame;
+  private:
+    std::vector<char> fragment;
+};
+}} // namespace qpid::framing
+
+#endif  /*!QPID_FRAMING_FRAMEDECODER_H*/