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sdlaudio: replace legacy functions with modern ones
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With the modern audio functions it's possible to add new
features like audio recording.

As a side effect this patch fixes a bug where SDL2 can't be used
on Windows. This bug was reported on the qemu-devel mailing list at

https://lists.nongnu.org/archive/html/qemu-devel/2020-01/msg04043.html

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 9315afe5-5958-c0b4-ea1e-14769511a9d5@t-online.de
Message-Id: <20210110100239.27588-7-vr_qemu@t-online.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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@kraxel
Volker Rümelin authored and kraxel committed Jan 15, 2021
1 parent e02d178 commit ce31f09
Showing 1 changed file with 50 additions and 57 deletions.
107 changes: 50 additions & 57 deletions audio/sdlaudio.c
View file
Expand Up @@ -41,15 +41,11 @@

typedef struct SDLVoiceOut {
HWVoiceOut hw;
} SDLVoiceOut;

static struct SDLAudioState {
int exit;
int initialized;
bool driver_created;
Audiodev *dev;
} glob_sdl;
typedef struct SDLAudioState SDLAudioState;
SDL_AudioDeviceID devid;
} SDLVoiceOut;

static void GCC_FMT_ATTR (1, 2) sdl_logerr (const char *fmt, ...)
{
Expand Down Expand Up @@ -155,9 +151,10 @@ static int sdl_to_audfmt(int sdlfmt, AudioFormat *fmt, int *endianness)
return 0;
}

static int sdl_open (SDL_AudioSpec *req, SDL_AudioSpec *obt)
static SDL_AudioDeviceID sdl_open(SDL_AudioSpec *req, SDL_AudioSpec *obt,
int rec)
{
int status;
SDL_AudioDeviceID devid;
#ifndef _WIN32
int err;
sigset_t new, old;
Expand All @@ -166,18 +163,19 @@ static int sdl_open (SDL_AudioSpec *req, SDL_AudioSpec *obt)
err = sigfillset (&new);
if (err) {
dolog ("sdl_open: sigfillset failed: %s\n", strerror (errno));
return -1;
return 0;
}
err = pthread_sigmask (SIG_BLOCK, &new, &old);
if (err) {
dolog ("sdl_open: pthread_sigmask failed: %s\n", strerror (err));
return -1;
return 0;
}
#endif

status = SDL_OpenAudio (req, obt);
if (status) {
sdl_logerr ("SDL_OpenAudio failed\n");
devid = SDL_OpenAudioDevice(NULL, rec, req, obt, 0);
if (!devid) {
sdl_logerr("SDL_OpenAudioDevice for %s failed\n",
rec ? "recording" : "playback");
}

#ifndef _WIN32
Expand All @@ -190,30 +188,32 @@ static int sdl_open (SDL_AudioSpec *req, SDL_AudioSpec *obt)
exit (EXIT_FAILURE);
}
#endif
return status;
return devid;
}

static void sdl_close (SDLAudioState *s)
static void sdl_close_out(SDLVoiceOut *sdl)
{
if (s->initialized) {
SDL_LockAudio();
s->exit = 1;
SDL_UnlockAudio();
SDL_PauseAudio (1);
SDL_CloseAudio ();
s->initialized = 0;
if (sdl->initialized) {
SDL_LockAudioDevice(sdl->devid);
sdl->exit = 1;
SDL_UnlockAudioDevice(sdl->devid);
SDL_PauseAudioDevice(sdl->devid, 1);
sdl->initialized = 0;
}
if (sdl->devid) {
SDL_CloseAudioDevice(sdl->devid);
sdl->devid = 0;
}
}

static void sdl_callback (void *opaque, Uint8 *buf, int len)
static void sdl_callback_out(void *opaque, Uint8 *buf, int len)
{
SDLVoiceOut *sdl = opaque;
SDLAudioState *s = &glob_sdl;
HWVoiceOut *hw = &sdl->hw;

if (!s->exit) {
if (!sdl->exit) {

/* dolog("callback: len=%d avail=%zu\n", len, hw->pending_emul); */
/* dolog("callback_out: len=%d avail=%zu\n", len, hw->pending_emul); */

while (hw->pending_emul && len) {
size_t write_len;
Expand All @@ -240,43 +240,44 @@ static void sdl_callback (void *opaque, Uint8 *buf, int len)
}
}

#define SDL_WRAPPER_FUNC(name, ret_type, args_decl, args) \
#define SDL_WRAPPER_FUNC(name, ret_type, args_decl, args, dir) \
static ret_type glue(sdl_, name)args_decl \
{ \
ret_type ret; \
glue(SDLVoice, dir) *sdl = (glue(SDLVoice, dir) *)hw; \
\
SDL_LockAudio(); \
SDL_LockAudioDevice(sdl->devid); \
ret = glue(audio_generic_, name)args; \
SDL_UnlockAudio(); \
SDL_UnlockAudioDevice(sdl->devid); \
\
return ret; \
}

SDL_WRAPPER_FUNC(get_buffer_out, void *, (HWVoiceOut *hw, size_t *size),
(hw, size))
(hw, size), Out)
SDL_WRAPPER_FUNC(put_buffer_out, size_t,
(HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size))
(HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size), Out)
SDL_WRAPPER_FUNC(write, size_t,
(HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size))
(HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size), Out)
#undef SDL_WRAPPER_FUNC

static void sdl_fini_out (HWVoiceOut *hw)
static void sdl_fini_out(HWVoiceOut *hw)
{
(void) hw;
SDLVoiceOut *sdl = (SDLVoiceOut *)hw;

sdl_close (&glob_sdl);
sdl_close_out(sdl);
}

static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
void *drv_opaque)
{
SDLVoiceOut *sdl = (SDLVoiceOut *) hw;
SDLAudioState *s = &glob_sdl;
SDLVoiceOut *sdl = (SDLVoiceOut *)hw;
SDL_AudioSpec req, obt;
int endianness;
int err;
AudioFormat effective_fmt;
AudiodevSdlPerDirectionOptions *spdo = s->dev->u.sdl.out;
Audiodev *dev = drv_opaque;
AudiodevSdlPerDirectionOptions *spdo = dev->u.sdl.out;
struct audsettings obt_as;

req.freq = as->freq;
Expand All @@ -288,16 +289,18 @@ static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
*/
req.samples = audio_buffer_samples(
qapi_AudiodevSdlPerDirectionOptions_base(spdo), as, 11610);
req.callback = sdl_callback;
req.callback = sdl_callback_out;
req.userdata = sdl;

if (sdl_open (&req, &obt)) {
sdl->dev = dev;
sdl->devid = sdl_open(&req, &obt, 0);
if (!sdl->devid) {
return -1;
}

err = sdl_to_audfmt(obt.format, &effective_fmt, &endianness);
if (err) {
sdl_close (s);
sdl_close_out(sdl);
return -1;
}

Expand All @@ -310,41 +313,31 @@ static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
hw->samples = (spdo->has_buffer_count ? spdo->buffer_count : 4) *
obt.samples;

s->initialized = 1;
s->exit = 0;
sdl->initialized = 1;
sdl->exit = 0;
return 0;
}

static void sdl_enable_out(HWVoiceOut *hw, bool enable)
{
SDL_PauseAudio(!enable);
SDLVoiceOut *sdl = (SDLVoiceOut *)hw;

SDL_PauseAudioDevice(sdl->devid, !enable);
}

static void *sdl_audio_init(Audiodev *dev)
{
SDLAudioState *s = &glob_sdl;
if (s->driver_created) {
sdl_logerr("Can't create multiple sdl backends\n");
return NULL;
}

if (SDL_InitSubSystem (SDL_INIT_AUDIO)) {
sdl_logerr ("SDL failed to initialize audio subsystem\n");
return NULL;
}

s->driver_created = true;
s->dev = dev;
return s;
return dev;
}

static void sdl_audio_fini (void *opaque)
{
SDLAudioState *s = opaque;
sdl_close (s);
SDL_QuitSubSystem (SDL_INIT_AUDIO);
s->driver_created = false;
s->dev = NULL;
}

static struct audio_pcm_ops sdl_pcm_ops = {
Expand Down

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