stored: remove BackendInterface layer

Instead of returning a factory that will then provide Device*, we can
return the Device* from the PluginRegistry's factory directly. This
removes the BackendInterface layer that wrapped the factory again.

core/src/stored/dev.cc

@@ -122,20 +122,14 @@ Device* FactoryCreateDevice(JobControlRecord* jcr,
   Dmsg1(400, "max_block_size in device_resource res is %u\n",
         device_resource->max_block_size);
 
-  if (!PluginRegistry<BackendInterface>::IsRegistered(
-          device_resource->dev_type)) {
+  if (!PluginRegistry<Device>::IsRegistered(device_resource->dev_type)) {
     Jmsg2(jcr, M_ERROR, 0, _("%s has an unknown device type %s\n"),
           device_resource->archive_device_string,
           device_resource->dev_type.c_str());
     return nullptr;
   }
 
-  // FIXME: the PluginRegistry should return the device instead of the factory
-  //        so we save one call and a delete.
-  auto factory
-      = PluginRegistry<BackendInterface>::Create(device_resource->dev_type);
-  Device* dev = factory->GetDevice();
-  delete factory;
+  Device* dev = PluginRegistry<Device>::Create(device_resource->dev_type);
 
   dev->device_resource = device_resource;
   device_resource->dev = dev;

core/src/stored/sd_backends.h

@@ -1,8 +1,7 @@
 /*
    BAREOS® - Backup Archiving REcovery Open Sourced
 
-   Copyright (C) 2014-2014 Planets Communications B.V.
-   Copyright (C) 2014-2022 Bareos GmbH & Co. KG
+   Copyright (C) 2022-2022 Bareos GmbH & Co. KG
 
    This program is Free Software; you can redistribute it and/or
    modify it under the terms of version three of the GNU Affero General Public
@@ -19,11 +18,6 @@
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA.
 */
-// Marco van Wieringen, June 2014
-/**
- * @file
- * Dynamic loading of SD backend plugins.
- */
 
 #ifndef BAREOS_STORED_SD_BACKENDS_H_
 #define BAREOS_STORED_SD_BACKENDS_H_
@@ -32,18 +26,8 @@
 
 namespace storagedaemon {
 
-class BackendInterface {
- public:
-  virtual ~BackendInterface() = default;
-  virtual Device* GetDevice() = 0;
-};
-
-template <typename T> class Backend : public BackendInterface {
- public:
-  Device* GetDevice(void) override { return new T(); }
-};
-
-template <typename T> BackendInterface* BackendFactory(void) { return new T(); }
+class Device;
+template <typename T> Device* DeviceFactory(void) { return new T(); }
 
 #if defined(HAVE_DYNAMIC_SD_BACKENDS)
 bool LoadStorageBackend(const std::string& dev_type,
@@ -52,8 +36,8 @@ bool LoadStorageBackend(const std::string& dev_type,
 
 #define REGISTER_SD_BACKEND(backend_name, backend_class) \
   [[maybe_unused]] static bool backend_name##_backend_   \
-      = PluginRegistry<BackendInterface>::Add(           \
-          #backend_name, BackendFactory<Backend<backend_class>>);
+      = PluginRegistry<Device>::Add(#backend_name,       \
+                                    DeviceFactory<backend_class>);
 
 }  // namespace storagedaemon
 

core/src/stored/sd_backends_dynamic.cc

@@ -65,7 +65,7 @@ bool LoadStorageBackend(const std::string& dev_type,
     return false;
   }
 
-  if (!PluginRegistry<BackendInterface>::IsRegistered(dev_type)) {
+  if (!PluginRegistry<Device>::IsRegistered(dev_type)) {
     Jmsg(nullptr, M_ERROR_TERM, 0,
          "Loaded backend library for %s did not register its backend. This is "
          "probably a bug in the backend library.\n",

core/src/stored/stored_conf.cc

@@ -547,20 +547,17 @@ static void GuessMissingDeviceTypes(ConfigurationParser& my_config)
 
 static void CheckAndLoadDeviceBackends(ConfigurationParser& my_config)
 {
-  PluginRegistry<BackendInterface>::DumpDbg();
-
 #if defined(HAVE_DYNAMIC_SD_BACKENDS)
   auto storage_res
       = dynamic_cast<StorageResource*>(my_config.GetNextRes(R_STORAGE, NULL));
 #endif
 
   BareosResource* p = nullptr;
-
   while ((p = my_config.GetNextRes(R_DEVICE, p)) != nullptr) {
     DeviceResource* d = dynamic_cast<DeviceResource*>(p);
     if (d) {
       to_lower(d->dev_type);
-      if (!PluginRegistry<BackendInterface>::IsRegistered(d->dev_type)) {
+      if (!PluginRegistry<Device>::IsRegistered(d->dev_type)) {
 #if defined(HAVE_DYNAMIC_SD_BACKENDS)
         if (!storage_res || storage_res->backend_directories.empty()) {
           Jmsg2(nullptr, M_ERROR_TERM, 0,