Start a new backend factory API

Using proper class inheritance. Be aware this breaks all backends except null
(and loopback). They will be restored individually in due time.

5 files changed, 86 insertions, 81 deletions

diff --git a/Alc/alc.cpp b/Alc/alc.cpp
index 9fee3251..04300d8a 100644
--- a/Alc/alc.cpp
+++ b/Alc/alc.cpp
@@ -57,6 +57,7 @@
 #include "almalloc.h"
 
 #include "backends/base.h"
+#include "backends/null.h"
 
 
 namespace {
@@ -66,10 +67,11 @@ namespace {
  ************************************************/
 struct BackendInfo {
     const char *name;
-    ALCbackendFactory* (*getFactory)(void);
+    BackendFactory& (*getFactory)(void);
 };
 
 struct BackendInfo BackendList[] = {
+#if 0
 #ifdef HAVE_JACK
     { "jack", ALCjackBackendFactory_getFactory },
 #endif
@@ -117,6 +119,8 @@ struct BackendInfo BackendList[] = {
 #ifdef HAVE_WAVE
     { "wave", ALCwaveBackendFactory_getFactory },
 #endif
+#endif /* 0 */
+    { "null", NullBackendFactory::getFactory },
 };
 ALsizei BackendListSize = COUNTOF(BackendList);
 #undef EmptyFuncs
@@ -1099,23 +1103,22 @@ static void alc_initconfig(void)
 
     for(n = i = 0;i < BackendListSize && (!PlaybackBackend.name || !CaptureBackend.name);i++)
     {
-        ALCbackendFactory *factory;
         BackendList[n] = BackendList[i];
 
-        factory = BackendList[n].getFactory();
-        if(!V0(factory,init)())
+        BackendFactory &factory = BackendList[n].getFactory();
+        if(!factory.init())
         {
             WARN("Failed to initialize backend \"%s\"\n", BackendList[n].name);
             continue;
         }
 
         TRACE("Initialized backend \"%s\"\n", BackendList[n].name);
-        if(!PlaybackBackend.name && V(factory,querySupport)(ALCbackend_Playback))
+        if(!PlaybackBackend.name && factory.querySupport(ALCbackend_Playback))
         {
             PlaybackBackend = BackendList[n];
             TRACE("Added \"%s\" for playback\n", PlaybackBackend.name);
         }
-        if(!CaptureBackend.name && V(factory,querySupport)(ALCbackend_Capture))
+        if(!CaptureBackend.name && factory.querySupport(ALCbackend_Capture))
         {
             CaptureBackend = BackendList[n];
             TRACE("Added \"%s\" for capture\n", CaptureBackend.name);
@@ -1212,10 +1215,8 @@ static void alc_deinit(void)
     memset(&CaptureBackend, 0, sizeof(CaptureBackend));
 
     for(i = 0;i < BackendListSize;i++)
-    {
-        ALCbackendFactory *factory = BackendList[i].getFactory();
-        V0(factory,deinit)();
-    }
+        BackendList[i].getFactory().deinit();
+
     {
         ALCbackendFactory *factory = ALCloopbackFactory_getFactory();
         V0(factory,deinit)();
@@ -1235,10 +1236,7 @@ static void ProbeDevices(std::string *list, struct BackendInfo *backendinfo, enu
     std::lock_guard<std::recursive_mutex> _{ListLock};
     list->clear();
     if(backendinfo->getFactory)
-    {
-        ALCbackendFactory *factory = backendinfo->getFactory();
-        V(factory,probe)(type, list);
-    }
+        backendinfo->getFactory().probe(type, list);
 }
 static void ProbeAllDevicesList(void)
 { ProbeDevices(&alcAllDevicesList, &PlaybackBackend, ALL_DEVICE_PROBE); }
@@ -3971,7 +3969,6 @@ ALC_API ALCdevice* ALC_APIENTRY alcGetContextsDevice(ALCcontext *Context)
  */
 ALC_API ALCdevice* ALC_APIENTRY alcOpenDevice(const ALCchar *deviceName)
 {
-    ALCbackendFactory *factory;
     const ALCchar *fmt;
     ALCdevice *device;
     ALCenum err;
@@ -4114,8 +4111,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcOpenDevice(const ALCchar *deviceName)
     device->NumStereoSources = 1;
     device->NumMonoSources = device->SourcesMax - device->NumStereoSources;
 
-    factory = PlaybackBackend.getFactory();
-    device->Backend = V(factory,createBackend)(device, ALCbackend_Playback);
+    device->Backend = PlaybackBackend.getFactory().createBackend(device, ALCbackend_Playback);
     if(!device->Backend)
     {
         FreeDevice(device);
@@ -4219,7 +4215,6 @@ ALC_API ALCboolean ALC_APIENTRY alcCloseDevice(ALCdevice *device)
  ************************************************/
 ALC_API ALCdevice* ALC_APIENTRY alcCaptureOpenDevice(const ALCchar *deviceName, ALCuint frequency, ALCenum format, ALCsizei samples)
 {
-    ALCbackendFactory *factory;
     ALCdevice *device = nullptr;
     ALCenum err;
 
@@ -4268,8 +4263,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcCaptureOpenDevice(const ALCchar *deviceName,
     device->UpdateSize = samples;
     device->NumUpdates = 1;
 
-    factory = CaptureBackend.getFactory();
-    device->Backend = V(factory,createBackend)(device, ALCbackend_Capture);
+    device->Backend = CaptureBackend.getFactory().createBackend(device, ALCbackend_Capture);
     if(!device->Backend)
     {
         FreeDevice(device);
@@ -4409,9 +4403,6 @@ ALC_API void ALC_APIENTRY alcCaptureSamples(ALCdevice *device, ALCvoid *buffer,
  */
 ALC_API ALCdevice* ALC_APIENTRY alcLoopbackOpenDeviceSOFT(const ALCchar *deviceName)
 {
-    ALCbackendFactory *factory;
-    ALCdevice *device;
-
     DO_INITCONFIG();
 
     /* Make sure the device name, if specified, is us. */
@@ -4421,7 +4412,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcLoopbackOpenDeviceSOFT(const ALCchar *deviceN
         return nullptr;
     }
 
-    device = static_cast<ALCdevice*>(al_calloc(16, sizeof(ALCdevice)));
+    ALCdevice *device{static_cast<ALCdevice*>(al_calloc(16, sizeof(ALCdevice)))};
     if(!device)
     {
         alcSetError(nullptr, ALC_OUT_OF_MEMORY);
@@ -4461,7 +4452,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcLoopbackOpenDeviceSOFT(const ALCchar *deviceN
     device->NumStereoSources = 1;
     device->NumMonoSources = device->SourcesMax - device->NumStereoSources;
 
-    factory = ALCloopbackFactory_getFactory();
+    ALCbackendFactory *factory = ALCloopbackFactory_getFactory();
     device->Backend = V(factory,createBackend)(device, ALCbackend_Loopback);
     if(!device->Backend)
     {
diff --git a/Alc/backends/base.h b/Alc/backends/base.h
index 360c2ffd..5f7deb62 100644
--- a/Alc/backends/base.h
+++ b/Alc/backends/base.h
@@ -153,10 +153,22 @@ ALCbackendFactory *ALCdsoundBackendFactory_getFactory(void);
 ALCbackendFactory *ALCwinmmBackendFactory_getFactory(void);
 ALCbackendFactory *ALCportBackendFactory_getFactory(void);
 ALCbackendFactory *ALCopenslBackendFactory_getFactory(void);
-ALCbackendFactory *ALCnullBackendFactory_getFactory(void);
 ALCbackendFactory *ALCwaveBackendFactory_getFactory(void);
 ALCbackendFactory *ALCsdl2BackendFactory_getFactory(void);
 ALCbackendFactory *ALCloopbackFactory_getFactory(void);
 
+
+struct BackendFactory {
+    virtual bool init() = 0;
+    virtual void deinit() { }
+
+    virtual bool querySupport(ALCbackend_Type type) = 0;
+
+    virtual void probe(enum DevProbe type, std::string *outnames) = 0;
+
+    virtual ALCbackend *createBackend(ALCdevice *device, ALCbackend_Type type) = 0;
+};
+
+
 #endif /* __cplusplus */
 #endif /* AL_BACKENDS_BASE_H */
diff --git a/Alc/backends/null.cpp b/Alc/backends/null.cpp
index 30d80b76..d376ccdf 100644
--- a/Alc/backends/null.cpp
+++ b/Alc/backends/null.cpp
@@ -20,6 +20,8 @@
 
 #include "config.h"
 
+#include "backends/null.h"
+
 #include <stdlib.h>
 #ifdef HAVE_WINDOWS_H
 #include <windows.h>
@@ -32,8 +34,6 @@
 #include "alu.h"
 #include "compat.h"
 
-#include "backends/base.h"
-
 
 namespace {
 
@@ -43,32 +43,31 @@ using std::chrono::nanoseconds;
 
 constexpr ALCchar nullDevice[] = "No Output";
 
-} // namespace
 
 struct ALCnullBackend final : public ALCbackend {
     ATOMIC(int) killNow;
     std::thread thread;
 };
 
-static int ALCnullBackend_mixerProc(ALCnullBackend *self);
-
-static void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device);
-static void ALCnullBackend_Destruct(ALCnullBackend *self);
-static ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name);
-static ALCboolean ALCnullBackend_reset(ALCnullBackend *self);
-static ALCboolean ALCnullBackend_start(ALCnullBackend *self);
-static void ALCnullBackend_stop(ALCnullBackend *self);
-static DECLARE_FORWARD2(ALCnullBackend, ALCbackend, ALCenum, captureSamples, void*, ALCuint)
-static DECLARE_FORWARD(ALCnullBackend, ALCbackend, ALCuint, availableSamples)
-static DECLARE_FORWARD(ALCnullBackend, ALCbackend, ClockLatency, getClockLatency)
-static DECLARE_FORWARD(ALCnullBackend, ALCbackend, void, lock)
-static DECLARE_FORWARD(ALCnullBackend, ALCbackend, void, unlock)
+int ALCnullBackend_mixerProc(ALCnullBackend *self);
+
+void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device);
+void ALCnullBackend_Destruct(ALCnullBackend *self);
+ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name);
+ALCboolean ALCnullBackend_reset(ALCnullBackend *self);
+ALCboolean ALCnullBackend_start(ALCnullBackend *self);
+void ALCnullBackend_stop(ALCnullBackend *self);
+DECLARE_FORWARD2(ALCnullBackend, ALCbackend, ALCenum, captureSamples, void*, ALCuint)
+DECLARE_FORWARD(ALCnullBackend, ALCbackend, ALCuint, availableSamples)
+DECLARE_FORWARD(ALCnullBackend, ALCbackend, ClockLatency, getClockLatency)
+DECLARE_FORWARD(ALCnullBackend, ALCbackend, void, lock)
+DECLARE_FORWARD(ALCnullBackend, ALCbackend, void, unlock)
 DECLARE_DEFAULT_ALLOCATORS(ALCnullBackend)
 
 DEFINE_ALCBACKEND_VTABLE(ALCnullBackend);
 
 
-static void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device)
+void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device)
 {
     new (self) ALCnullBackend{};
     ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
@@ -77,14 +76,14 @@ static void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device)
     ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
-static void ALCnullBackend_Destruct(ALCnullBackend *self)
+void ALCnullBackend_Destruct(ALCnullBackend *self)
 {
     ALCbackend_Destruct(STATIC_CAST(ALCbackend, self));
     self->~ALCnullBackend();
 }
 
 
-static int ALCnullBackend_mixerProc(ALCnullBackend *self)
+int ALCnullBackend_mixerProc(ALCnullBackend *self)
 {
     ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
     const milliseconds restTime{device->UpdateSize*1000/device->Frequency / 2};
@@ -131,7 +130,7 @@ static int ALCnullBackend_mixerProc(ALCnullBackend *self)
 }
 
 
-static ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name)
+ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name)
 {
     ALCdevice *device;
 
@@ -147,13 +146,13 @@ static ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name)
     return ALC_NO_ERROR;
 }
 
-static ALCboolean ALCnullBackend_reset(ALCnullBackend *self)
+ALCboolean ALCnullBackend_reset(ALCnullBackend *self)
 {
     SetDefaultWFXChannelOrder(STATIC_CAST(ALCbackend, self)->mDevice);
     return ALC_TRUE;
 }
 
-static ALCboolean ALCnullBackend_start(ALCnullBackend *self)
+ALCboolean ALCnullBackend_start(ALCnullBackend *self)
 {
     try {
         ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
@@ -168,7 +167,7 @@ static ALCboolean ALCnullBackend_start(ALCnullBackend *self)
     return ALC_FALSE;
 }
 
-static void ALCnullBackend_stop(ALCnullBackend *self)
+void ALCnullBackend_stop(ALCnullBackend *self)
 {
     if(ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel) ||
        !self->thread.joinable())
@@ -176,46 +175,22 @@ static void ALCnullBackend_stop(ALCnullBackend *self)
     self->thread.join();
 }
 
-
-struct ALCnullBackendFactory final : public ALCbackendFactory {
-    ALCnullBackendFactory() noexcept;
-};
-
-ALCbackendFactory *ALCnullBackendFactory_getFactory(void);
-
-static ALCboolean ALCnullBackendFactory_init(ALCnullBackendFactory *self);
-static DECLARE_FORWARD(ALCnullBackendFactory, ALCbackendFactory, void, deinit)
-static ALCboolean ALCnullBackendFactory_querySupport(ALCnullBackendFactory *self, ALCbackend_Type type);
-static void ALCnullBackendFactory_probe(ALCnullBackendFactory *self, enum DevProbe type, std::string *outnames);
-static ALCbackend* ALCnullBackendFactory_createBackend(ALCnullBackendFactory *self, ALCdevice *device, ALCbackend_Type type);
-DEFINE_ALCBACKENDFACTORY_VTABLE(ALCnullBackendFactory);
-
-ALCnullBackendFactory::ALCnullBackendFactory() noexcept
-  : ALCbackendFactory{GET_VTABLE2(ALCnullBackendFactory, ALCbackendFactory)}
-{
-}
-
-
-ALCbackendFactory *ALCnullBackendFactory_getFactory(void)
-{
-    static ALCnullBackendFactory factory{};
-    return STATIC_CAST(ALCbackendFactory, &factory);
-}
+} // namespace
 
 
-static ALCboolean ALCnullBackendFactory_init(ALCnullBackendFactory* UNUSED(self))
+bool NullBackendFactory::init()
 {
-    return ALC_TRUE;
+    return true;
 }
 
-static ALCboolean ALCnullBackendFactory_querySupport(ALCnullBackendFactory* UNUSED(self), ALCbackend_Type type)
+bool NullBackendFactory::querySupport(ALCbackend_Type type)
 {
     if(type == ALCbackend_Playback)
-        return ALC_TRUE;
-    return ALC_FALSE;
+        return true;
+    return false;
 }
 
-static void ALCnullBackendFactory_probe(ALCnullBackendFactory* UNUSED(self), enum DevProbe type, std::string *outnames)
+void NullBackendFactory::probe(enum DevProbe type, std::string *outnames)
 {
     switch(type)
     {
@@ -228,7 +203,7 @@ static void ALCnullBackendFactory_probe(ALCnullBackendFactory* UNUSED(self), enu
     }
 }
 
-static ALCbackend* ALCnullBackendFactory_createBackend(ALCnullBackendFactory* UNUSED(self), ALCdevice *device, ALCbackend_Type type)
+ALCbackend *NullBackendFactory::createBackend(ALCdevice *device, ALCbackend_Type type)
 {
     if(type == ALCbackend_Playback)
     {
@@ -240,3 +215,9 @@ static ALCbackend* ALCnullBackendFactory_createBackend(ALCnullBackendFactory* UN
 
     return NULL;
 }
+
+BackendFactory &NullBackendFactory::getFactory()
+{
+    static NullBackendFactory factory{};
+    return factory;
+}
diff --git a/Alc/backends/null.h b/Alc/backends/null.h
new file mode 100644
index 00000000..e2adfc33
--- /dev/null
+++ b/Alc/backends/null.h
@@ -0,0 +1,20 @@
+#ifndef BACKENDS_NULL_H
+#define BACKENDS_NULL_H
+
+#include "backends/base.h"
+
+struct NullBackendFactory final : public BackendFactory {
+public:
+    bool init() override;
+    /*void deinit() override;*/
+
+    bool querySupport(ALCbackend_Type type) override;
+
+    void probe(enum DevProbe type, std::string *outnames) override;
+
+    ALCbackend *createBackend(ALCdevice *device, ALCbackend_Type type) override;
+
+    static BackendFactory &getFactory();
+};
+
+#endif /* BACKENDS_NULL_H */
diff --git a/CMakeLists.txt b/CMakeLists.txt
index aa85e34b..d3718332 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -992,6 +992,7 @@ SET(ALC_OBJS  ${ALC_OBJS}
     # Default backends, always available
     Alc/backends/loopback.cpp
     Alc/backends/null.cpp
+    Alc/backends/null.h
 )
 
 # Check ALSA backend