mixer: factorize backend emix infra

Summary:
The mixer gadgets suffer of a bad design between old and new gadget infra.
This commit refactorize the mixer backend to get only one instance
between old and new gadget. This resolve many problems as e_client_volume
integration or the default_sink choosen in one of this modules.
Now it will be easier to maintain this code and better support when we will
remove old gadget infra.

Reviewers: zmike, devilhorns, stephenmhouston

Reviewed By: zmike

Subscribers: cedric

Tags: #enlightenment-git

Differential Revision: https://phab.enlightenment.org/D7718

src/modules/mixer/gadget/backend.h

@@ -0,0 +1,24 @@
+#ifndef MIXER_GADGET_BACKEND_
+#define MIXER_GADGET_BACKEND_
+
+typedef void (*Backend_Hook)(void);
+
+EINTERN extern int E_EVENT_MIXER_BACKEND_CHANGED;
+EINTERN extern int E_EVENT_MIXER_SINKS_CHANGED;
+
+EINTERN int backend_init(void);
+EINTERN int backend_shutdown(void);
+
+EINTERN void backend_emixer_exec(void);
+
+EINTERN void backend_volume_set(unsigned int volume);
+EINTERN unsigned int backend_volume_get(void);
+EINTERN void backend_volume_decrease(void);
+EINTERN void backend_volume_increase(void);
+EINTERN void backend_mute_set(Eina_Bool mute);
+EINTERN Eina_Bool backend_mute_get(void);
+
+EINTERN void backend_sink_default_set(const Emix_Sink *s);
+EINTERN const Emix_Sink *backend_sink_default_get(void);
+
+#endif /* MIXER_GADGET_BACKEND */

src/modules/mixer/gadget/mod.c

@@ -1,10 +1,13 @@
 #include "mixer.h"
+#include "backend.h"
 
 EINTERN int _e_gemix_log_domain;
 
 EINTERN void *
 e_modapi_gadget_init(E_Module *m)
 {
+   if (!backend_init()) return NULL;
+
    _e_gemix_log_domain = eina_log_domain_register("mixer_gadget", EINA_COLOR_RED);
 
    e_gadget_type_add("Mixer", mixer_gadget_create, NULL);
@@ -19,7 +22,7 @@ e_modapi_gadget_shutdown(E_Module *m EINA_UNUSED)
 
    e_gadget_type_del("Mixer");
 
-   emix_shutdown();
+   backend_shutdown();
 
    return 1;
 }

src/modules/mixer/meson.build

@@ -5,7 +5,8 @@ src = files(
   'e_mod_main.h',
   'gadget/mixer.h',
   'gadget/mixer.c',
-  'gadget/mod.c'
+  'gadget/mod.c',
+  'gadget/backend.c'
  )
 
 mixer_lib = files(