Initial work on audio device hotplug support.

This fills in the core pieces and fully implements it for Mac OS X.

Most other platforms, at the moment, will report a disconnected device if
it fails to write audio, but don't notice if the system's device list changed
at all.

--HG--
extra : rebase_source : f7e7efbbeecfe58338b0f325340c358c2bdfc402

test/testaudiohotplug.c

@@ -0,0 +1,182 @@
+/*
+  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.
+*/
+
+/* Program to test hotplugging of audio devices */
+
+#include "SDL_config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#if HAVE_SIGNAL_H
+#include <signal.h>
+#endif
+
+#ifdef __EMSCRIPTEN__
+#include <emscripten/emscripten.h>
+#endif
+
+#include "SDL.h"
+
+static SDL_AudioSpec spec;
+static Uint8 *sound = NULL;     /* Pointer to wave data */
+static Uint32 soundlen = 0;     /* Length of wave data */
+
+static int posindex = 0;
+static Uint32 positions[64];
+
+/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
+static void
+quit(int rc)
+{
+    SDL_Quit();
+    exit(rc);
+}
+
+void SDLCALL
+fillerup(void *_pos, Uint8 * stream, int len)
+{
+    Uint32 pos = *((Uint32 *) _pos);
+    Uint8 *waveptr;
+    int waveleft;
+
+    /* Set up the pointers */
+    waveptr = sound + pos;
+    waveleft = soundlen - pos;
+
+    /* Go! */
+    while (waveleft <= len) {
+        SDL_memcpy(stream, waveptr, waveleft);
+        stream += waveleft;
+        len -= waveleft;
+        waveptr = sound;
+        waveleft = soundlen;
+        pos = 0;
+    }
+    SDL_memcpy(stream, waveptr, len);
+    pos += len;
+    *((Uint32 *) _pos) = pos;
+}
+
+static int done = 0;
+void
+poked(int sig)
+{
+    done = 1;
+}
+
+static void
+iteration()
+{
+    SDL_Event e;
+    SDL_AudioDeviceID dev;
+    while (SDL_PollEvent(&e)) {
+        if (e.type == SDL_QUIT) {
+            done = 1;
+        } else if (e.type == SDL_AUDIODEVICEADDED) {
+            const char *name = SDL_GetAudioDeviceName(e.adevice.which, 0);
+            SDL_Log("New %s audio device: %s\n", e.adevice.iscapture ? "capture" : "output", name);
+            if (!e.adevice.iscapture) {
+                positions[posindex] = 0;
+                spec.userdata = &positions[posindex++];
+                spec.callback = fillerup;
+                dev = SDL_OpenAudioDevice(name, 0, &spec, NULL, 0);
+                if (!dev) {
+                    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open '%s': %s\n", name, SDL_GetError());
+                } else {
+                    SDL_Log("Opened '%s' as %u\n", name, (unsigned int) dev);
+                    SDL_PauseAudioDevice(dev, 0);
+                }
+            }
+        } else if (e.type == SDL_AUDIODEVICEREMOVED) {
+            dev = (SDL_AudioDeviceID) e.adevice.which;
+            SDL_Log("%s device %u removed.\n", e.adevice.iscapture ? "capture" : "output", (unsigned int) dev);
+            SDL_CloseAudioDevice(dev);
+        }
+    }
+}
+
+#ifdef __EMSCRIPTEN__
+void
+loop()
+{
+    if(done)
+        emscripten_cancel_main_loop();
+    else
+        iteration();
+}
+#endif
+
+int
+main(int argc, char *argv[])
+{
+    int i;
+    char filename[4096];
+
+	/* Enable standard application logging */
+	SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
+
+    /* Load the SDL library */
+    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) < 0) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
+        return (1);
+    }
+
+    SDL_CreateWindow("testaudiohotplug", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, 0);
+
+    if (argc > 1) {
+        SDL_strlcpy(filename, argv[1], sizeof(filename));
+    } else {
+        SDL_strlcpy(filename, "sample.wav", sizeof(filename));
+    }
+    /* Load the wave file into memory */
+    if (SDL_LoadWAV(filename, &spec, &sound, &soundlen) == NULL) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't load %s: %s\n", filename, SDL_GetError());
+        quit(1);
+    }
+
+#if HAVE_SIGNAL_H
+    /* Set the signals */
+#ifdef SIGHUP
+    signal(SIGHUP, poked);
+#endif
+    signal(SIGINT, poked);
+#ifdef SIGQUIT
+    signal(SIGQUIT, poked);
+#endif
+    signal(SIGTERM, poked);
+#endif /* HAVE_SIGNAL_H */
+
+    /* Show the list of available drivers */
+    SDL_Log("Available audio drivers:");
+    for (i = 0; i < SDL_GetNumAudioDrivers(); ++i) {
+		SDL_Log("%i: %s", i, SDL_GetAudioDriver(i));
+    }
+
+    SDL_Log("Using audio driver: %s\n", SDL_GetCurrentAudioDriver());
+
+#ifdef __EMSCRIPTEN__
+    emscripten_set_main_loop(loop, 0, 1);
+#else
+    while (!done) {
+        SDL_Delay(100);
+        iteration();
+    }
+#endif
+
+    /* Clean up on signal */
+    SDL_Quit();
+    SDL_FreeWAV(sound);
+    return (0);
+}
+
+/* vi: set ts=4 sw=4 expandtab: */