Bunch of reworking to how we manage audio devices.

Device enumeration now happens at startup and then is managed exclusively through hotplugging instead of full redetection. The device name list now has a unique "handle" associated with each item and SDL will pass this to the backend so they don't have to figure out how a human readable name maps to real hardware for a second time. Other cleanups, fixes, improvements, plus all the audio backends updated to the new interface...largely untested at this point, though.
libsdl-org · Mar 18, 2015 · f9cfd9f · f9cfd9f
1 parent 0e02ce0
commit f9cfd9f
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Showing 27 changed files with 430 additions and 575 deletions.
diff --git a/src/audio/SDL_audio.c b/src/audio/SDL_audio.c
diff --git a/src/audio/SDL_audiodev.c b/src/audio/SDL_audiodev.c
@@ -46,18 +46,21 @@
 #define _PATH_DEV_AUDIO "/dev/audio"
 #endif
 
-static SDL_INLINE void
-test_device(const char *fname, int flags, int (*test) (int fd),
-            SDL_AddAudioDevice addfn)
+static void
+test_device(const int iscapture, const char *fname, int flags, int (*test) (int fd))
 {
     struct stat sb;
     if ((stat(fname, &sb) == 0) && (S_ISCHR(sb.st_mode))) {
         const int audio_fd = open(fname, flags, 0);
         if (audio_fd >= 0) {
-            if (test(audio_fd)) {
-                addfn(fname);
-            }
+            const int okay = test(audio_fd);
             close(audio_fd);
+            if (okay) {
+                static size_t dummyhandle = 0;
+                dummyhandle++;
+                SDL_assert(dummyhandle != 0);
+                SDL_AddAudioDevice(iscapture, fname, (void *) dummyhandle);
+            }
         }
     }
 }
@@ -68,11 +71,10 @@ test_stub(int fd)
     return 1;
 }
 
-void
-SDL_EnumUnixAudioDevices(int iscapture, int classic, int (*test)(int fd),
-                         SDL_AddAudioDevice addfn)
+static void
+SDL_EnumUnixAudioDevices_Internal(const int iscapture, const int classic, int (*test)(int))
 {
-    const int flags = ((iscapture) ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT);
+    const int flags = iscapture ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT;
     const char *audiodev;
     char audiopath[1024];
 
@@ -97,17 +99,25 @@ SDL_EnumUnixAudioDevices(int iscapture, int classic, int (*test)(int fd),
             }
         }
     }
-    test_device(audiodev, flags, test, addfn);
+    test_device(iscapture, audiodev, flags, test);
 
     if (SDL_strlen(audiodev) < (sizeof(audiopath) - 3)) {
         int instance = 0;
         while (instance++ <= 64) {
             SDL_snprintf(audiopath, SDL_arraysize(audiopath),
                          "%s%d", audiodev, instance);
-            test_device(audiopath, flags, test, addfn);
+            test_device(iscapture, audiopath, flags, test);
         }
     }
 }
 
+void
+SDL_EnumUnixAudioDevices(const int classic, int (*test)(int))
+{
+    SDL_EnumUnixAudioDevices_Internal(SDL_TRUE, classic, test);
+    SDL_EnumUnixAudioDevices_Internal(SDL_FALSE, classic, test);
+}
+
 #endif /* Audio driver selection */
+
 /* vi: set ts=4 sw=4 expandtab: */
diff --git a/src/audio/SDL_audiodev_c.h b/src/audio/SDL_audiodev_c.h
@@ -33,7 +33,6 @@
 #define OPEN_FLAGS_INPUT (O_RDONLY|O_NONBLOCK)
 #endif
 
-void SDL_EnumUnixAudioDevices(int iscapture, int classic,
-                              int (*test) (int fd), SDL_AddAudioDevice addfn);
+extern void SDL_EnumUnixAudioDevices(const int classic, int (*test)(int));
 
 /* vi: set ts=4 sw=4 expandtab: */
diff --git a/src/audio/SDL_sysaudio.h b/src/audio/SDL_sysaudio.h
@@ -30,16 +30,20 @@
 typedef struct SDL_AudioDevice SDL_AudioDevice;
 #define _THIS   SDL_AudioDevice *_this
 
-/* Used by audio targets during DetectDevices() */
-typedef int (*SDL_AddAudioDevice)(const char *name);
+/* Audio targets should call this as devices are added to the system (such as
+   a USB headset being plugged in), and should also be called for
+   for every device found during DetectDevices(). */
+extern void SDL_AddAudioDevice(const int iscapture, const char *name, void *handle);
 
-/* Audio targets should call this as devices are hotplugged. Don't call
-   during DetectDevices(), this is for hotplugging a device later. */
-extern void SDL_AudioDeviceConnected(const int iscapture, const char *name);
+/* Audio targets should call this as devices are removed, so SDL can update
+   its list of available devices. */
+extern void SDL_RemoveAudioDevice(void *handle);
 
-/* Audio targets should call this as devices are unplugged.
-  (device) can be NULL if an unopened device is lost. */
-extern void SDL_AudioDeviceDisconnected(const int iscapture, SDL_AudioDevice *device);
+/* Audio targets should call this if an opened audio device is lost while
+   being used. This can happen due to i/o errors, or a device being unplugged,
+   etc. If the device is totally gone, please also call SDL_RemoveAudioDevice()
+   as appropriate so SDL's list of devices is accurate. */
+extern void SDL_OpenedAudioDeviceDisconnected(SDL_AudioDevice *device);
 
 
 /* This is the size of a packet when using SDL_QueueAudio(). We allocate
@@ -64,8 +68,8 @@ typedef struct SDL_AudioBufferQueue
 
 typedef struct SDL_AudioDriverImpl
 {
-    void (*DetectDevices) (int iscapture, SDL_AddAudioDevice addfn);
-    int (*OpenDevice) (_THIS, const char *devname, int iscapture);
+    void (*DetectDevices) (void);
+    int (*OpenDevice) (_THIS, void *handle, const char *devname, int iscapture);
     void (*ThreadInit) (_THIS); /* Called by audio thread at start */
     void (*WaitDevice) (_THIS);
     void (*PlayDevice) (_THIS);
@@ -75,6 +79,7 @@ typedef struct SDL_AudioDriverImpl
     void (*CloseDevice) (_THIS);
     void (*LockDevice) (_THIS);
     void (*UnlockDevice) (_THIS);
+    void (*FreeDeviceHandle) (void *handle);  /**< SDL is done with handle from SDL_AddAudioDevice() */
     void (*Deinitialize) (void);
 
     /* !!! FIXME: add pause(), so we can optimize instead of mixing silence. */
@@ -86,9 +91,18 @@ typedef struct SDL_AudioDriverImpl
     int HasCaptureSupport;
     int OnlyHasDefaultOutputDevice;
     int OnlyHasDefaultInputDevice;
+    int AllowsArbitraryDeviceNames;
 } SDL_AudioDriverImpl;
 
 
+typedef struct SDL_AudioDeviceItem
+{
+    void *handle;
+    struct SDL_AudioDeviceItem *next;
+    char name[];
+} SDL_AudioDeviceItem;
+
+
 typedef struct SDL_AudioDriver
 {
     /* * * */
@@ -102,16 +116,13 @@ typedef struct SDL_AudioDriver
     SDL_AudioDriverImpl impl;
 
     /* A mutex for device detection */
-    SDL_mutex *detection_lock;
-
-    SDL_bool need_capture_device_redetect;
-    SDL_bool need_output_device_redetect;
-
-    char **outputDevices;
+    SDL_mutex *detectionLock;
+    SDL_bool captureDevicesRemoved;
+    SDL_bool outputDevicesRemoved;
     int outputDeviceCount;
-
-    char **inputDevices;
     int inputDeviceCount;
+    SDL_AudioDeviceItem *outputDevices;
+    SDL_AudioDeviceItem *inputDevices;
 } SDL_AudioDriver;
 
 

diff --git a/src/audio/alsa/SDL_alsa_audio.c b/src/audio/alsa/SDL_alsa_audio.c
@@ -320,7 +320,7 @@ ALSA_PlayDevice(_THIS)
                 /* Hmm, not much we can do - abort */
                 fprintf(stderr, "ALSA write failed (unrecoverable): %s\n",
                         ALSA_snd_strerror(status));
-                SDL_AudioDeviceDisconnected(SDL_FALSE, this);
+                SDL_OpenedAudioDeviceDisconnected(this);
                 return;
             }
             continue;
@@ -465,7 +465,7 @@ ALSA_set_buffer_size(_THIS, snd_pcm_hw_params_t *params, int override)
 }
 
 static int
-ALSA_OpenDevice(_THIS, const char *devname, int iscapture)
+ALSA_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
 {
     int status = 0;
     snd_pcm_t *pcm_handle = NULL;

diff --git a/src/audio/android/SDL_androidaudio.c b/src/audio/android/SDL_androidaudio.c
@@ -35,7 +35,7 @@
 static SDL_AudioDevice* audioDevice = NULL;
 
 static int
-AndroidAUD_OpenDevice(_THIS, const char *devname, int iscapture)
+AndroidAUD_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
 {
     SDL_AudioFormat test_format;
 

diff --git a/src/audio/arts/SDL_artsaudio.c b/src/audio/arts/SDL_artsaudio.c
@@ -151,7 +151,7 @@ ARTS_WaitDevice(_THIS)
         /* Check every 10 loops */
         if (this->hidden->parent && (((++cnt) % 10) == 0)) {
             if (kill(this->hidden->parent, 0) < 0 && errno == ESRCH) {
-                SDL_AudioDeviceDisconnected(SDL_FALSE, this);
+                SDL_OpenedAudioDeviceDisconnected(this);
             }
         }
     }
@@ -179,7 +179,7 @@ ARTS_PlayDevice(_THIS)
 
     /* If we couldn't write, assume fatal error for now */
     if (written < 0) {
-        SDL_AudioDeviceDisconnected(SDL_FALSE, this);
+        SDL_OpenedAudioDeviceDisconnected(this);
     }
 #ifdef DEBUG_AUDIO
     fprintf(stderr, "Wrote %d bytes of audio data\n", written);
@@ -229,7 +229,7 @@ ARTS_Suspend(void)
 }
 
 static int
-ARTS_OpenDevice(_THIS, const char *devname, int iscapture)
+ARTS_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
 {
     int rc = 0;
     int bits = 0, frag_spec = 0;

diff --git a/src/audio/bsd/SDL_bsdaudio.c b/src/audio/bsd/SDL_bsdaudio.c
@@ -51,9 +51,9 @@
 
 
 static void
-BSDAUDIO_DetectDevices(int iscapture, SDL_AddAudioDevice addfn)
+BSDAUDIO_DetectDevices(void)
 {
-    SDL_EnumUnixAudioDevices(iscapture, 0, NULL, addfn);
+    SDL_EnumUnixAudioDevices(0, NULL);
 }
 
 
@@ -150,7 +150,7 @@ BSDAUDIO_WaitDevice(_THIS)
                the user know what happened.
              */
             fprintf(stderr, "SDL: %s\n", message);
-            SDL_AudioDeviceDisconnected(SDL_FALSE, this);
+            SDL_OpenedAudioDeviceDisconnected(this);
             /* Don't try to close - may hang */
             this->hidden->audio_fd = -1;
 #ifdef DEBUG_AUDIO
@@ -195,7 +195,7 @@ BSDAUDIO_PlayDevice(_THIS)
 
     /* If we couldn't write, assume fatal error for now */
     if (written < 0) {
-        SDL_AudioDeviceDisconnected(SDL_FALSE, this);
+        SDL_OpenedAudioDeviceDisconnected(this);
     }
 #ifdef DEBUG_AUDIO
     fprintf(stderr, "Wrote %d bytes of audio data\n", written);
@@ -224,7 +224,7 @@ BSDAUDIO_CloseDevice(_THIS)
 }
 
 static int
-BSDAUDIO_OpenDevice(_THIS, const char *devname, int iscapture)
+BSDAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
 {
     const int flags = ((iscapture) ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT);
     SDL_AudioFormat format = 0;
@@ -348,6 +348,8 @@ BSDAUDIO_Init(SDL_AudioDriverImpl * impl)
     impl->GetDeviceBuf = BSDAUDIO_GetDeviceBuf;
     impl->CloseDevice = BSDAUDIO_CloseDevice;
 
+    impl->AllowsArbitraryDeviceNames = 1;
+
     return 1;   /* this audio target is available. */
 }