SDL: Revert "audio: Device threads don't increment physical device refcounts."

SDL Commits
1 
From 33c9eeec7cda9da3a97543ae70289ac365acf297 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sun, 22 Oct 2023 16:14:01 -0400
Subject: [PATCH] Revert "audio: Device threads don't increment physical device
 refcounts."

This reverts commit 76f81797b71e12391ce434582b911ef4f6b61390.

This worked in the normal cases, but:

A device thread that calls SDL_DisconnectAudioDevice due to failure will fire
the disconnect event from the device thread...and if there's an event watcher
that uses that moment to close the device, we still end up in the same
situation, where the device thread tries to join on itself.

Better solutions are still pending.
---
 src/audio/SDL_audio.c                      | 6 ++++--
 src/audio/emscripten/SDL_emscriptenaudio.c | 2 ++
 src/audio/haiku/SDL_haikuaudio.cc          | 2 ++
 src/audio/jack/SDL_jackaudio.c             | 2 ++
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/audio/SDL_audio.c b/src/audio/SDL_audio.c
index 05e1ffac9b55..b96dae2d9c72 100644
--- a/src/audio/SDL_audio.c
+++ b/src/audio/SDL_audio.c
@@ -848,6 +848,7 @@ void SDL_QuitAudio(void)
 
 void SDL_AudioThreadFinalize(SDL_AudioDevice *device)
 {
+    UnrefPhysicalAudioDevice(device);
 }
 
 static void MixFloat32Audio(float *dst, const float *src, const int buffer_size)
@@ -863,6 +864,7 @@ static void MixFloat32Audio(float *dst, const float *src, const int buffer_size)
 void SDL_OutputAudioThreadSetup(SDL_AudioDevice *device)
 {
     SDL_assert(!device->iscapture);
+    RefPhysicalAudioDevice(device);  // unref'd when the audio thread terminates (ProvidesOwnCallbackThread implementations should call SDL_AudioThreadFinalize appropriately).
     current_audio.impl.ThreadInit(device);
 }
 
@@ -1012,6 +1014,7 @@ static int SDLCALL OutputAudioThread(void *devicep)  // thread entry point
 void SDL_CaptureAudioThreadSetup(SDL_AudioDevice *device)
 {
     SDL_assert(device->iscapture);
+    RefPhysicalAudioDevice(device);  // unref'd when the audio thread terminates (ProvidesOwnCallbackThread implementations should call SDL_AudioThreadFinalize appropriately).
     current_audio.impl.ThreadInit(device);
 }
 
@@ -1351,14 +1354,13 @@ void SDL_CloseAudioDevice(SDL_AudioDeviceID devid)
     if (logdev) {
         SDL_AudioDevice *device = logdev->physical_device;
         DestroyLogicalAudioDevice(logdev);
+        UnrefPhysicalAudioDevice(device);  // one reference for each logical device.
 
         // !!! FIXME: we _need_ to release this lock, but doing so can cause a race condition if someone opens a device while we're closing it.
         SDL_UnlockMutex(device->lock);  // can't hold the lock or the audio thread will deadlock while we WaitThread it. If not closing, we're done anyhow.
         if (device->logical_devices == NULL) {  // no more logical devices? Close the physical device, too.
             ClosePhysicalAudioDevice(device);
         }
-
-        UnrefPhysicalAudioDevice(device);  // one reference for each logical device.
     }
 }
 
diff --git a/src/audio/emscripten/SDL_emscriptenaudio.c b/src/audio/emscripten/SDL_emscriptenaudio.c
index 32afd20bc87a..368499227fb8 100644
--- a/src/audio/emscripten/SDL_emscriptenaudio.c
+++ b/src/audio/emscripten/SDL_emscriptenaudio.c
@@ -181,6 +181,8 @@ static int EMSCRIPTENAUDIO_OpenDevice(SDL_AudioDevice *device)
         return SDL_OutOfMemory();
     }
 
+    RefPhysicalAudioDevice(device);  // CloseDevice will always unref this through SDL_AudioThreadFinalize, even if we failed to start the thread.
+
     // limit to native freq
     device->spec.freq = EM_ASM_INT({ return Module['SDL3'].audioContext.sampleRate; });
 
diff --git a/src/audio/haiku/SDL_haikuaudio.cc b/src/audio/haiku/SDL_haikuaudio.cc
index 5772fbe05650..f52dae593ef7 100644
--- a/src/audio/haiku/SDL_haikuaudio.cc
+++ b/src/audio/haiku/SDL_haikuaudio.cc
@@ -111,6 +111,8 @@ static int HAIKUAUDIO_OpenDevice(SDL_AudioDevice *device)
     }
     SDL_zerop(device->hidden);
 
+    RefPhysicalAudioDevice(device);  // CloseDevice will always unref this through SDL_AudioThreadFinalize, even if we failed to start the thread.
+
     // Parse the audio format and fill the Be raw audio format
     media_raw_audio_format format;
     SDL_zero(format);
diff --git a/src/audio/jack/SDL_jackaudio.c b/src/audio/jack/SDL_jackaudio.c
index 77e2f03fa990..703122c8a8aa 100644
--- a/src/audio/jack/SDL_jackaudio.c
+++ b/src/audio/jack/SDL_jackaudio.c
@@ -300,6 +300,8 @@ static int JACK_OpenDevice(SDL_AudioDevice *device)
         return SDL_OutOfMemory();
     }
 
+    RefPhysicalAudioDevice(device);  // CloseDevice will always unref this through SDL_AudioThreadFinalize, even if we failed to start the thread.
+
     client = JACK_jack_client_open(GetJackAppName(), JackNoStartServer, &status, NULL);
     device->hidden->client = client;
     if (client == NULL) {