conf: allow param==NULL

Return the default value in the conf_get_block_*() functions when
param==NULL was passed.

This simplifies a lot of code, because all initialization can be done
in one code path, regardless whether configuration is present.

src/conf.c

@@ -433,6 +433,9 @@ getBlockParam(const struct config_param * param, const char *name)
 	struct block_param *ret = NULL;
 	int i;
 
+	if (param == NULL)
+		return NULL;
+
 	for (i = 0; i < param->num_block_params; i++) {
 		if (0 == strcmp(name, param->block_params[i].name)) {
 			if (ret) {

src/mixer/alsa_mixer.c

@@ -48,9 +48,6 @@ alsa_mixer_configure(struct mixer_data *data, const struct config_param *param)
 	struct alsa_mixer *am = (struct alsa_mixer *)data;
 	const char *value;
 
-	if (param == NULL)
-		return;
-
 	value = config_get_block_string(param, "mixer_device", NULL);
 	if (value != NULL) {
 		g_free(am->device);

src/mixer/oss_mixer.c

@@ -52,9 +52,6 @@ oss_mixer_configure(struct mixer_data *data, const struct config_param *param)
 	struct oss_mixer *om = (struct oss_mixer *) data;
 	const char *value;
 
-	if (param == NULL)
-		return;
-
 	value = config_get_block_string(param, "mixer_device", NULL);
 	if (value != NULL) {
 		g_free(om->device);

src/output/alsa_plugin.c

@@ -85,13 +85,9 @@ alsa_data_new(void)
 {
 	struct alsa_data *ret = g_new(struct alsa_data, 1);
 
-	ret->device = NULL;
 	ret->mode = 0;
 	ret->pcm = NULL;
 	ret->writei = snd_pcm_writei;
-	ret->use_mmap = false;
-	ret->buffer_time = MPD_ALSA_BUFFER_TIME_US;
-	ret->period_time = MPD_ALSA_PERIOD_TIME_US;
 
 	//use alsa mixer by default
 	mixer_init(&ret->mixer, &alsa_mixer);
@@ -149,8 +145,9 @@ alsa_init(G_GNUC_UNUSED struct audio_output *ao,
 		free_global_registered = 1;
 	}
 
-	if (param) {
 	alsa_configure(ad, param);
+
+	if (param) {
 		mixer_configure(&ad->mixer, param);
 	}
 

src/output/jack_plugin.c

@@ -60,16 +60,6 @@ mpd_jack_name(const struct jack_data *jd)
 	return audio_output_get_name(jd->ao);
 }
 
-static struct jack_data *
-mpd_jack_new(void)
-{
-	struct jack_data *ret = g_new(struct jack_data, 1);
-
-	ret->ringbuffer_size = 32768;
-
-	return ret;
-}
-
 static void
 mpd_jack_client_free(struct jack_data *jd)
 {
@@ -188,12 +178,10 @@ mpd_jack_init(struct audio_output *ao,
 	struct jack_data *jd;
 	const char *value;
 
-	jd = mpd_jack_new();
+	jd = g_new(struct jack_data, 1);
 	jd->ao = ao;
 
 	g_debug("mpd_jack_init (pid=%d)", getpid());
-	if (param == NULL)
-		return jd;
 
 	value = config_get_block_string(param, "ports", NULL);
 	if (value != NULL) {

src/output/oss_plugin.c

@@ -392,16 +392,14 @@ oss_initDriver(G_GNUC_UNUSED struct audio_output *audioOutput,
 	       G_GNUC_UNUSED const struct audio_format *audio_format,
 	       const struct config_param *param)
 {
-	if (param) {
+	const char *device = config_get_block_string(param, "device", NULL);
-		const char *device =
-			config_get_block_string(param, "device", NULL);
 	if (device != NULL) {
 		OssData *od = newOssData();
 		od->device = device;
 		mixer_configure(&od->mixer, param);
 		return od;
 	}
-	}
+
 	return oss_open_default(param);
 }