turns out that shared_from_this() can not be called from the constructor, so we made a special attach() function to postpone object initialization

include/channel.h

@@ -27,7 +27,11 @@ public:
      *  Construct a channel object
      *  @param  connection
      */
-    Channel(Connection *connection) : _implementation(ChannelImpl::instantiate(this, connection)) {}
+    Channel(Connection *connection) : _implementation(new ChannelImpl()) 
+    {
+        // attach the connection to the channel
+        _implementation->attach(connection);
+    }
 
     /**
      *  Destructor

include/channelimpl.h

@@ -25,17 +25,11 @@ class ConsumedMessage;
 class ChannelImpl : public Watchable, public std::enable_shared_from_this<ChannelImpl>
 {
 private:
-    /**
-     *  The actual channel object
-     *  @var    Channel
-     */
-    Channel *_parent;
-
     /**
      *  Pointer to the connection
      *  @var    ConnectionImpl
      */
-    ConnectionImpl *_connection;
+    ConnectionImpl *_connection = nullptr;
 
     /**
      *  Callback when the channel is ready
@@ -74,7 +68,7 @@ private:
      *  The channel number
      *  @var uint16_t
      */
-    uint16_t _id;
+    uint16_t _id = 0;
 
     /**
      *  State of the channel object
@@ -84,7 +78,7 @@ private:
         state_connected,
         state_closing,
         state_closed
-    } _state = state_connected;
+    } _state = state_closed;
 
     /**
      *  The frames that still need to be send out
@@ -109,11 +103,10 @@ private:
     ConsumedMessage *_message = nullptr;
 
     /**
-     *  Constructor to make a shared pointer
+     *  Attach the connection
-     *  @param  parent          the publis channel object
+     *  @param  connection
-     *  @param  connection      pointer to the connection
      */
-    static std::shared_ptr<ChannelImpl> instantiate(Channel *parent, Connection *connection);
+    void attach(Connection *connection);
 
     /**
      *  Push a deferred result
@@ -136,11 +129,8 @@ protected:
      *  Note that the constructor is private, and that the Channel class is
      *  a friend. By doing this we ensure that nobody can instantiate this
      *  object, and that it can thus only be used inside the library.
-     *
-     *  @param  parent          the public channel object
-     *  @param  connection      pointer to the connection
      */
-    ChannelImpl(Channel *parent, Connection *connection);
+    ChannelImpl() {}
 
 public:
     /**
@@ -152,7 +142,7 @@ public:
      *  Invalidate the channel
      *  This method is called when the connection is destructed
      */
-    void invalidate()
+    void detach()
     {
         _connection = nullptr;
     }

src/channelimpl.cpp

@@ -46,66 +46,6 @@
  */
 namespace AMQP {
 
-/**
- *  Derived class with public constructor
- * 
- *  We need this because std::make_shared<ChannelImpl> is not possible
- */
-struct PublicChannelImpl : public ChannelImpl
-{
-    /**
-     *  Constructor
-     *  @param  parent
-     *  @param  connection
-     */
-    PublicChannelImpl(Channel *parent, Connection *connection) : ChannelImpl(parent, connection) {}
-    
-    /**
-     *  Destructor
-     */
-    virtual ~PublicChannelImpl() {}
-};
-
-/**
- *  Constructor to make a shared pointer
- *  @param  parent          the publis channel object
- *  @param  connection      pointer to the connection
- */
-std::shared_ptr<ChannelImpl> ChannelImpl::instantiate(Channel *parent, Connection *connection)
-{
-    // we can only use std::make_shared with a PublicChannelImpl
-    return std::make_shared<PublicChannelImpl>(parent, connection);
-}
-
-/**
- *  Construct a channel object
- *  @param  parent
- *  @param  connection
- *  @param  handler
- */
-ChannelImpl::ChannelImpl(Channel *parent, Connection *connection) :
-    _parent(parent),
-    _connection(&connection->_implementation)
-{
-    // add the channel to the connection
-    _id = _connection->add(shared_from_this());
-
-    // check if the id is valid
-    if (_id == 0)
-    {
-        // this is invalid
-        _state = state_closed;
-    }
-    else
-    {
-        // busy connecting
-        _state = state_connected;
-
-        // valid id, send a channel open frame
-        send(ChannelOpenFrame(_id));
-    }
-}
-
 /**
  *  Destructor
  */
@@ -122,6 +62,34 @@ ChannelImpl::~ChannelImpl()
     while (_oldestCallback) _oldestCallback.reset(_oldestCallback->next());
 }
 
+/**
+ *  Initialize the object with an connection
+ *  @param  connection
+ */
+void ChannelImpl::attach(Connection *connection)
+{
+    // get connection impl
+    _connection = &connection->_implementation;
+    
+    // retrieve an ID
+    _id = _connection->add(shared_from_this());
+    
+    // check if the id is valid
+    if (_id == 0)
+    {
+        // this is invalid
+        _state = state_closed;
+    }
+    else
+    {
+        // busy connecting
+        _state = state_connected;
+        
+        // valid id, send a channel open frame
+        send(ChannelOpenFrame(_id));
+    }
+}    
+
 /**
  *  Push a deferred result
  *  @param  result          The deferred object to push

src/connectionimpl.cpp

@@ -45,7 +45,7 @@ ConnectionImpl::~ConnectionImpl()
     close();
 
     // invalidate all channels, so they will no longer call methods on this channel object
-    for (auto iter = _channels.begin(); iter != _channels.end(); iter++) iter->second->invalidate();
+    for (auto iter = _channels.begin(); iter != _channels.end(); iter++) iter->second->detach();
 }
 
 /**