Chrome's Native Client backend implementation

src/audio/SDL_audio.c

@@ -51,6 +51,9 @@ extern AudioBootStrap QSAAUDIO_bootstrap;
 extern AudioBootStrap SUNAUDIO_bootstrap;
 extern AudioBootStrap ARTS_bootstrap;
 extern AudioBootStrap ESD_bootstrap;
+#if SDL_AUDIO_DRIVER_NACL
+extern AudioBootStrap NACLAUD_bootstrap;
+#endif
 extern AudioBootStrap NAS_bootstrap;
 extern AudioBootStrap XAUDIO2_bootstrap;
 extern AudioBootStrap DSOUND_bootstrap;
@@ -69,6 +72,7 @@ extern AudioBootStrap ANDROIDAUD_bootstrap;
 extern AudioBootStrap PSPAUD_bootstrap;
 extern AudioBootStrap SNDIO_bootstrap;
 
+
 /* Available audio drivers */
 static const AudioBootStrap *const bootstrap[] = {
 #if SDL_AUDIO_DRIVER_PULSEAUDIO
@@ -98,6 +102,9 @@ static const AudioBootStrap *const bootstrap[] = {
 #if SDL_AUDIO_DRIVER_ESD
     &ESD_bootstrap,
 #endif
+#if SDL_AUDIO_DRIVER_NACL
+   &NACLAUD_bootstrap,
+#endif
 #if SDL_AUDIO_DRIVER_NAS
     &NAS_bootstrap,
 #endif

src/audio/nacl/SDL_naclaudio.c

@@ -0,0 +1,135 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "../../SDL_internal.h"
+#include "SDL_naclaudio.h"
+
+#include "SDL_audio.h"
+#include "SDL_mutex.h"
+#include "../SDL_audiomem.h"
+#include "../SDL_audio_c.h"
+#include "../SDL_audiodev_c.h"
+
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/pp_instance.h"
+#include "ppapi_simple/ps.h"
+#include "ppapi_simple/ps_interface.h"
+#include "ppapi_simple/ps_event.h"
+
+/* The tag name used by NACL audio */
+#define NACLAUD_DRIVER_NAME         "nacl"
+
+#define SAMPLE_FRAME_COUNT 4096
+
+/* Audio driver functions */
+static int NACLAUD_OpenDevice(_THIS, const char *devname, int iscapture);
+static void NACLAUD_CloseDevice(_THIS);
+static void nacl_audio_callback(void* samples, uint32_t buffer_size, PP_TimeDelta latency, void* data);
+
+/* FIXME: Make use of latency if needed */
+static void nacl_audio_callback(void* samples, uint32_t buffer_size, PP_TimeDelta latency, void* data) {
+    SDL_AudioDevice* _this = (SDL_AudioDevice*) data;
+    
+    SDL_LockMutex(private->mutex);
+    /*if (private->opened) {*/
+    SDL_memset(samples, _this->spec.silence, buffer_size);
+    SDL_LockMutex(_this->mixer_lock);
+    (*_this->spec.callback)(_this->spec.userdata, (Uint8*)samples, buffer_size);
+    SDL_UnlockMutex(_this->mixer_lock);
+    /*} else {
+        SDL_memset(samples, 0, buffer_size);
+    }*/
+    SDL_UnlockMutex(private->mutex);
+    
+    return;
+}
+
+static void NACLAUD_CloseDevice(SDL_AudioDevice *device) {
+    const PPB_Core *core = PSInterfaceCore();
+    const PPB_Audio *ppb_audio = PSInterfaceAudio();
+    SDL_PrivateAudioData *hidden = (SDL_PrivateAudioData *) device->hidden;
+    
+    ppb_audio->StopPlayback(hidden->audio);
+    SDL_DestroyMutex(hidden->mutex);
+    core->ReleaseResource(hidden->audio);
+}
+
+static int
+NACLAUD_OpenDevice(_THIS, const char *devname, int iscapture) {
+    PP_Instance instance = PSGetInstanceId();
+    const PPB_Audio *ppb_audio = PSInterfaceAudio();
+    const PPB_AudioConfig *ppb_audiocfg = PSInterfaceAudioConfig();
+    
+    private = (SDL_PrivateAudioData *) SDL_calloc(1, (sizeof *private));
+    if (private == NULL) {
+        SDL_OutOfMemory();
+        return 0;
+    }
+    
+    private->mutex = SDL_CreateMutex();
+    _this->spec.freq = 44100;
+    _this->spec.format = AUDIO_S16LSB;
+    _this->spec.channels = 2;
+    _this->spec.samples = ppb_audiocfg->RecommendSampleFrameCount(
+        instance, 
+        PP_AUDIOSAMPLERATE_44100, 
+        SAMPLE_FRAME_COUNT);
+    
+    private->audio = ppb_audio->Create(
+        instance,
+        ppb_audiocfg->CreateStereo16Bit(instance, PP_AUDIOSAMPLERATE_44100, _this->spec.samples),
+        nacl_audio_callback, 
+        _this);
+    
+    /* Start audio playback while we are still on the main thread. */
+    ppb_audio->StartPlayback(private->audio);
+    
+    return 1;
+}
+
+static int
+NACLAUD_Init(SDL_AudioDriverImpl * impl)
+{
+    if (PSGetInstanceId() == 0) {
+        return 0;
+    }
+    
+    /* Set the function pointers */
+    impl->OpenDevice = NACLAUD_OpenDevice;
+    impl->CloseDevice = NACLAUD_CloseDevice;
+    impl->HasCaptureSupport = 0;
+    impl->OnlyHasDefaultOutputDevice = 1;
+    impl->OnlyHasDefaultInputDevice = 1;
+    impl->ProvidesOwnCallbackThread = 1;
+    /*
+     *    impl->WaitDevice = NACLAUD_WaitDevice;
+     *    impl->GetDeviceBuf = NACLAUD_GetDeviceBuf;
+     *    impl->PlayDevice = NACLAUD_PlayDevice;
+     *    impl->Deinitialize = NACLAUD_Deinitialize;
+     */
+    
+    return 1;
+}
+
+AudioBootStrap NACLAUD_bootstrap = {
+    NACLAUD_DRIVER_NAME, "SDL NaCl Audio Driver",
+    NACLAUD_Init, 0
+};

src/audio/nacl/SDL_naclaudio.h

@@ -0,0 +1,41 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "../../SDL_internal.h"
+
+#ifndef _SDL_naclaudio_h
+#define _SDL_naclaudio_h
+
+#include "SDL_audio.h"
+#include "../SDL_sysaudio.h"
+#include "SDL_mutex.h"
+
+#include "ppapi/c/ppb_audio.h"
+
+#define _THIS  SDL_AudioDevice *_this
+#define private _this->hidden
+
+typedef struct SDL_PrivateAudioData {
+  SDL_mutex* mutex;
+  PP_Resource audio;
+} SDL_PrivateAudioData;
+
+#endif /* _SDL_naclaudio_h */