4 files changed, 33 insertions, 36 deletions

diff --git a/libs/ardour/ardour/audio_backend.h b/libs/ardour/ardour/audio_backend.h
index 6c4a54da3e..d9561a62e5 100644
--- a/libs/ardour/ardour/audio_backend.h
+++ b/libs/ardour/ardour/audio_backend.h
@@ -29,17 +29,15 @@
 #include <boost/function.hpp>
 
 #include "ardour/types.h"
+#include "ardour/audioengine.h"
+#include "ardour/port_engine.h"
 
 namespace ARDOUR {
 
-class AudioEngine;
-class PortEngine;
-class PortManager;
-
-class AudioBackend {
+class AudioBackend : public PortEngine {
   public:
 
-    AudioBackend (AudioEngine& e) : engine (e){}
+    AudioBackend (AudioEngine& e) : PortEngine (e), engine (e) {}
     virtual ~AudioBackend () {}
 
     /** Return the name of this backend.
@@ -49,17 +47,6 @@ class AudioBackend {
      */
     virtual std::string name() const = 0;
 
-    /** Return a private, type-free pointer to any data
-     * that might be useful to a concrete implementation
-     */
-    virtual void* private_handle() const = 0;
-
-    /** Return true if the underlying mechanism/API is still available
-     * for us to utilize. return false if some or all of the AudioBackend
-     * API can no longer be effectively used.
-     */
-    virtual bool connected() const = 0;
-
     /** Return true if the callback from the underlying mechanism/API
      * (CoreAudio, JACK, ASIO etc.) occurs in a thread subject to realtime
      * constraints. Return false otherwise.
@@ -416,11 +403,22 @@ class AudioBackend {
 struct AudioBackendInfo {
     const char* name;
 
+    /** Using arg1 and arg2, initialize this audiobackend.
+     * 
+     * Returns zero on success, non-zero otherwise.
+     */
     int (*instantiate) (const std::string& arg1, const std::string& arg2);
+
+    /** Release all resources associated with this audiobackend
+     */
     int (*deinstantiate) (void);
 
-    boost::shared_ptr<AudioBackend> (*backend_factory) (AudioEngine&);
-    boost::shared_ptr<PortEngine> (*portengine_factory) (PortManager&);
+    /** Factory method to create an AudioBackend-derived class.
+     * 
+     * Returns a valid shared_ptr to the object if successfull,
+     * or a "null" shared_ptr otherwise.
+     */
+    boost::shared_ptr<AudioBackend> (*factory) (AudioEngine&);
 
     /** Return true if the underlying mechanism/API has been
      * configured and does not need (re)configuration in order
diff --git a/libs/ardour/ardour/audioengine.h b/libs/ardour/ardour/audioengine.h
index 5762e709b3..201d960479 100644
--- a/libs/ardour/ardour/audioengine.h
+++ b/libs/ardour/ardour/audioengine.h
@@ -200,8 +200,6 @@ public:
 
     static AudioEngine*       _instance;
 
-    boost::shared_ptr<AudioBackend> _backend;
-
     Glib::Threads::Mutex      _process_lock;
     Glib::Threads::Cond        session_removed;
     bool                       session_remove_pending;
diff --git a/libs/ardour/ardour/port_engine.h b/libs/ardour/ardour/port_engine.h
index 71f93ea05e..8c0ec9e754 100644
--- a/libs/ardour/ardour/port_engine.h
+++ b/libs/ardour/ardour/port_engine.h
@@ -79,6 +79,11 @@ class PortEngine {
     PortEngine (PortManager& pm) : manager (pm) {}
     virtual ~PortEngine() {}
     
+    /** Return a private, type-free pointer to any data
+     * that might be useful to a concrete implementation
+     */
+    virtual void* private_handle() const = 0;
+
     /* We use void* here so that the API can be defined for any implementation.
      * 
      * We could theoretically use a template (PortEngine<T>) and define
@@ -89,21 +94,16 @@ class PortEngine {
        
     typedef void* PortHandle;
 
-    /** Return a typeless pointer to an object that may be of interest
-     * that understands the internals of a particular PortEngine
-     * implementation.
-     *
-     * XXX the existence of this method is a band-aid over some design
-     * issues and will it will be removed in the future
-     */
-    virtual void* private_handle() const = 0;
-
-    virtual bool connected() const = 0;
-
     /** Return the name of this process as used by the port manager
      * when naming ports.
      */
     virtual const std::string& my_name() const = 0;
+ 
+    /** Return true if the underlying mechanism/API is still available
+     * for us to utilize. return false if some or all of the AudioBackend
+     * API can no longer be effectively used.
+     */
+    virtual bool available() const = 0;
 
     /** Return the maximum size of a port name 
      */
diff --git a/libs/ardour/ardour/port_manager.h b/libs/ardour/ardour/port_manager.h
index 6d45597a41..ba15142d83 100644
--- a/libs/ardour/ardour/port_manager.h
+++ b/libs/ardour/ardour/port_manager.h
@@ -34,10 +34,12 @@
 #include "ardour/chan_count.h"
 #include "ardour/midiport_manager.h"
 #include "ardour/port.h"
-#include "ardour/port_engine.h"
 
 namespace ARDOUR {
 
+class PortEngine;
+class AudioBackend;
+
 class PortManager 
 {
   public:
@@ -47,8 +49,7 @@ class PortManager
     PortManager ();
     virtual ~PortManager() {}
 
-    void set_port_engine (PortEngine& pe);
-    PortEngine& port_engine() { return *_impl; }
+    PortEngine& port_engine();
 
     uint32_t port_name_size() const;
     std::string my_name() const;
@@ -134,7 +135,7 @@ class PortManager
     PBD::Signal5<void, boost::weak_ptr<Port>, std::string, boost::weak_ptr<Port>, std::string, bool> PortConnectedOrDisconnected;
 
   protected:
-    boost::shared_ptr<PortEngine> _impl;
+    boost::shared_ptr<AudioBackend> _backend;
     SerializedRCUManager<Ports> ports;
     bool _port_remove_in_progress;