text: /* Spa ALSA Sink
   *
   * Copyright © 2018 Wim Taymans
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  
  #include <stddef.h>
  
  #include <alsa/asoundlib.h>
  
  #include <spa/node/node.h>
  #include <spa/node/utils.h>
  #include <spa/node/keys.h>
  #include <spa/monitor/device.h>
  #include <spa/utils/keys.h>
  #include <spa/utils/names.h>
  #include <spa/param/audio/format.h>
  #include <spa/pod/filter.h>
  #include <spa/debug/pod.h>
  
  #define NAME "alsa-pcm-sink"
  
  #include "alsa-pcm.h"
  
  #define CHECK_PORT(this,d,p)    ((d) == SPA_DIRECTION_INPUT && (p) == 0)
  
  static const char default_device[] = "hw:0";
  static const uint32_t default_min_latency = MIN_LATENCY;
  static const uint32_t default_max_latency = MAX_LATENCY;
  
  static void reset_props(struct props *props)
  {
  	strncpy(props->device, default_device, 64);
  	props->min_latency = default_min_latency;
  	props->max_latency = default_max_latency;
  	props->use_chmap = DEFAULT_USE_CHMAP;
  }
  
  static int impl_node_enum_params(void *object, int seq,
  				 uint32_t id, uint32_t start, uint32_t num,
  				 const struct spa_pod *filter)
  {
  	struct state *this = object;
  	struct spa_pod *param;
  	struct spa_pod_builder b = { 0 };
  	uint8_t buffer[1024];
  	struct spa_result_node_params result;
  	uint32_t count = 0;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(num != 0, -EINVAL);
  
  	result.id = id;
  	result.next = start;
        next:
  	result.index = result.next++;
  
  	spa_pod_builder_init(&b, buffer, sizeof(buffer));
  
  	switch (id) {
  	case SPA_PARAM_PropInfo:
  	{
  		struct props *p = &this->props;
  
  		switch (result.index) {
  		case 0:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_PropInfo, id,
  				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_device),
  				SPA_PROP_INFO_name, SPA_POD_String("The ALSA device"),
  				SPA_PROP_INFO_type, SPA_POD_Stringn(p->device, sizeof(p->device)));
  			break;
  		case 1:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_PropInfo, id,
  				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_deviceName),
  				SPA_PROP_INFO_name, SPA_POD_String("The ALSA device name"),
  				SPA_PROP_INFO_type, SPA_POD_Stringn(p->device_name, sizeof(p->device_name)));
  			break;
  		case 2:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_PropInfo, id,
  				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_cardName),
  				SPA_PROP_INFO_name, SPA_POD_String("The ALSA card name"),
  				SPA_PROP_INFO_type, SPA_POD_Stringn(p->card_name, sizeof(p->card_name)));
  			break;
  		case 3:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_PropInfo, id,
  				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_minLatency),
  				SPA_PROP_INFO_name, SPA_POD_String("The minimum latency"),
  				SPA_PROP_INFO_type, SPA_POD_CHOICE_RANGE_Int(p->min_latency, 1, INT32_MAX));
  			break;
  		case 4:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_PropInfo, id,
  				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_maxLatency),
  				SPA_PROP_INFO_name, SPA_POD_String("The maximum latency"),
  				SPA_PROP_INFO_type, SPA_POD_CHOICE_RANGE_Int(p->max_latency, 1, INT32_MAX));
  			break;
  		case 5:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_PropInfo, id,
  				SPA_PROP_INFO_id,   SPA_POD_Id(SPA_PROP_START_CUSTOM),
  				SPA_PROP_INFO_name, SPA_POD_String("Use the driver channelmap"),
  				SPA_PROP_INFO_type, SPA_POD_Bool(p->use_chmap));
  			break;
  		default:
  			return 0;
  		}
  		break;
  	}
  	case SPA_PARAM_Props:
  	{
  		struct props *p = &this->props;
  
  		switch (result.index) {
  		case 0:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_Props, id,
  				SPA_PROP_device,       SPA_POD_Stringn(p->device, sizeof(p->device)),
  				SPA_PROP_deviceName,   SPA_POD_Stringn(p->device_name, sizeof(p->device_name)),
  				SPA_PROP_cardName,     SPA_POD_Stringn(p->card_name, sizeof(p->card_name)),
  				SPA_PROP_minLatency,   SPA_POD_Int(p->min_latency),
  				SPA_PROP_maxLatency,   SPA_POD_Int(p->max_latency),
  				SPA_PROP_START_CUSTOM, SPA_POD_Bool(p->use_chmap));
  			break;
  		default:
  			return 0;
  		}
  		break;
  	}
  	case SPA_PARAM_IO:
  		switch (result.index) {
  		case 0:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_ParamIO, id,
  				SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_Clock),
  				SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_clock)));
  			break;
  		case 1:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_ParamIO, id,
  				SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_Position),
  				SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_position)));
  			break;
  		default:
  			return 0;
  		}
  		break;
  
  	default:
  		return -ENOENT;
  	}
  
  	if (spa_pod_filter(&b, &result.param, param, filter) < 0)
  		goto next;
  
  	spa_node_emit_result(&this->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);
  
  	if (++count != num)
  		goto next;
  
  	return 0;
  }
  
  static int impl_node_set_io(void *object, uint32_t id, void *data, size_t size)
  {
  	struct state *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	switch (id) {
  	case SPA_IO_Clock:
  		this->clock = data;
  		break;
  	case SPA_IO_Position:
  		this->position = data;
  		break;
  	default:
  		return -ENOENT;
  	}
  	spa_alsa_reassign_follower(this);
  
  	return 0;
  }
  
  static int impl_node_set_param(void *object, uint32_t id, uint32_t flags,
  			       const struct spa_pod *param)
  {
  	struct state *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	if (id == SPA_PARAM_Props) {
  		struct props *p = &this->props;
  
  		if (param == NULL) {
  			reset_props(p);
  			return 0;
  		}
  		spa_pod_parse_object(param,
  			SPA_TYPE_OBJECT_Props, NULL,
  			SPA_PROP_device,       SPA_POD_OPT_Stringn(p->device, sizeof(p->device)),
  			SPA_PROP_minLatency,   SPA_POD_OPT_Int(&p->min_latency),
  			SPA_PROP_maxLatency,   SPA_POD_OPT_Int(&p->max_latency),
  			SPA_PROP_START_CUSTOM, SPA_POD_OPT_Bool(&p->use_chmap));
  	}
  	else
  		return -ENOENT;
  
  	return 0;
  }
  
  static int impl_node_send_command(void *object, const struct spa_command *command)
  {
  	struct state *this = object;
  	int res;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(command != NULL, -EINVAL);
  
  	switch (SPA_NODE_COMMAND_ID(command)) {
  	case SPA_NODE_COMMAND_ParamBegin:
  		if ((res = spa_alsa_open(this)) < 0)
  			return res;
  		break;
  	case SPA_NODE_COMMAND_ParamEnd:
  		if (this->have_format)
  			return 0;
  		if ((res = spa_alsa_close(this)) < 0)
  			return res;
  		break;
  	case SPA_NODE_COMMAND_Start:
  		if (!this->have_format)
  			return -EIO;
  		if (this->n_buffers == 0)
  			return -EIO;
  
  		if ((res = spa_alsa_start(this)) < 0)
  			return res;
  		break;
  	case SPA_NODE_COMMAND_Suspend:
  	case SPA_NODE_COMMAND_Pause:
  		if ((res = spa_alsa_pause(this)) < 0)
  			return res;
  		break;
  	default:
  		return -ENOTSUP;
  	}
  	return 0;
  }
  
  
  static void emit_node_info(struct state *this, bool full)
  {
  	if (full)
  		this->info.change_mask = this->info_all;
  	if (this->info.change_mask) {
  		struct spa_dict_item items[4];
  		uint32_t n_items = 0;
  		char latency[64];
  
  		items[n_items++] = SPA_DICT_ITEM_INIT(SPA_KEY_DEVICE_API, "alsa");
  		items[n_items++] = SPA_DICT_ITEM_INIT(SPA_KEY_MEDIA_CLASS, "Audio/Sink");
  		items[n_items++] = SPA_DICT_ITEM_INIT(SPA_KEY_NODE_DRIVER, "true");
  		if (this->have_format) {
  			snprintf(latency, sizeof(latency), "%lu/%d", this->buffer_frames / 4, this->rate);
  			items[n_items++] = SPA_DICT_ITEM_INIT(SPA_KEY_NODE_MAX_LATENCY, latency);
  		}
  		this->info.props = &SPA_DICT_INIT(items, n_items);
  
  		spa_node_emit_info(&this->hooks, &this->info);
  		this->info.change_mask = 0;
  	}
  }
  
  static void emit_port_info(struct state *this, bool full)
  {
  	if (full)
  		this->port_info.change_mask = this->port_info_all;
  	if (this->port_info.change_mask) {
  		spa_node_emit_port_info(&this->hooks,
  				SPA_DIRECTION_INPUT, 0, &this->port_info);
  		this->port_info.change_mask = 0;
  	}
  }
  
  static int
  impl_node_add_listener(void *object,
  		struct spa_hook *listener,
  		const struct spa_node_events *events,
  		void *data)
  {
  	struct state *this = object;
  	struct spa_hook_list save;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	spa_hook_list_isolate(&this->hooks, &save, listener, events, data);
  
  	emit_node_info(this, true);
  	emit_port_info(this, true);
  
  	spa_hook_list_join(&this->hooks, &save);
  
  	return 0;
  }
  
  static int
  impl_node_set_callbacks(void *object,
  			const struct spa_node_callbacks *callbacks,
  			void *data)
  {
  	struct state *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	this->callbacks = SPA_CALLBACKS_INIT(callbacks, data);
  
  	return 0;
  }
  
  static int
  impl_node_sync(void *object, int seq)
  {
  	struct state *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	spa_node_emit_result(&this->hooks, seq, 0, 0, NULL);
  
  	return 0;
  }
  
  static int impl_node_add_port(void *object, enum spa_direction direction, uint32_t port_id,
  		const struct spa_dict *props)
  {
  	return -ENOTSUP;
  }
  
  static int impl_node_remove_port(void *object, enum spa_direction direction, uint32_t port_id)
  {
  	return -ENOTSUP;
  }
  
  static int
  impl_node_port_enum_params(void *object, int seq,
  			   enum spa_direction direction, uint32_t port_id,
  			   uint32_t id, uint32_t start, uint32_t num,
  			   const struct spa_pod *filter)
  {
  
  	struct state *this = object;
  	struct spa_pod *param;
  	struct spa_pod_builder b = { 0 };
  	uint8_t buffer[1024];
  	struct spa_result_node_params result;
  	uint32_t count = 0;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  	spa_return_val_if_fail(num != 0, -EINVAL);
  
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	result.id = id;
  	result.next = start;
        next:
  	result.index = result.next++;
  
  	spa_pod_builder_init(&b, buffer, sizeof(buffer));
  
  	switch (id) {
  	case SPA_PARAM_EnumFormat:
  		return spa_alsa_enum_format(this, seq, start, num, filter);
  
  	case SPA_PARAM_Format:
  		if (!this->have_format)
  			return -EIO;
  		if (result.index > 0)
  			return 0;
  
  		param = spa_format_audio_raw_build(&b, id, &this->current_format.info.raw);
  		break;
  
  	case SPA_PARAM_Buffers:
  		if (!this->have_format)
  			return -EIO;
  		if (result.index > 0)
  			return 0;
  
  		param = spa_pod_builder_add_object(&b,
  			SPA_TYPE_OBJECT_ParamBuffers, id,
  			SPA_PARAM_BUFFERS_buffers, SPA_POD_CHOICE_RANGE_Int(2, 1, MAX_BUFFERS),
  			SPA_PARAM_BUFFERS_blocks,  SPA_POD_Int(this->blocks),
  			SPA_PARAM_BUFFERS_size,    SPA_POD_CHOICE_RANGE_Int(
  							this->props.max_latency * this->frame_size,
  							this->props.min_latency * this->frame_size,
  							INT32_MAX),
  			SPA_PARAM_BUFFERS_stride,  SPA_POD_Int(this->frame_size),
  			SPA_PARAM_BUFFERS_align,   SPA_POD_Int(16));
  		break;
  
  	case SPA_PARAM_Meta:
  		switch (result.index) {
  		case 0:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_ParamMeta, id,
  				SPA_PARAM_META_type, SPA_POD_Id(SPA_META_Header),
  				SPA_PARAM_META_size, SPA_POD_Int(sizeof(struct spa_meta_header)));
  			break;
  		default:
  			return 0;
  		}
  		break;
  
  	case SPA_PARAM_IO:
  		switch (result.index) {
  		case 0:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_ParamIO, id,
  				SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_Buffers),
  				SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_buffers)));
  			break;
  		case 1:
  			param = spa_pod_builder_add_object(&b,
  				SPA_TYPE_OBJECT_ParamIO, id,
  				SPA_PARAM_IO_id,   SPA_POD_Id(SPA_IO_RateMatch),
  				SPA_PARAM_IO_size, SPA_POD_Int(sizeof(struct spa_io_rate_match)));
  			break;
  		default:
  			return 0;
  		}
  		break;
  
  	default:
  		return -ENOENT;
  	}
  
  	if (spa_pod_filter(&b, &result.param, param, filter) < 0)
  		goto next;
  
  	spa_node_emit_result(&this->hooks, seq, 0, SPA_RESULT_TYPE_NODE_PARAMS, &result);
  
  	if (++count != num)
  		goto next;
  
  	return 0;
  }
  
  static int clear_buffers(struct state *this)
  {
  	if (this->n_buffers > 0) {
  		spa_list_init(&this->ready);
  		this->n_buffers = 0;
  	}
  	return 0;
  }
  
  static int port_set_format(void *object,
  			   enum spa_direction direction, uint32_t port_id,
  			   uint32_t flags,
  			   const struct spa_pod *format)
  {
  	struct state *this = object;
  	int err;
  
  	if (format == NULL) {
  		if (!this->have_format)
  			return 0;
  
  		spa_log_debug(this->log, "clear format");
  		spa_alsa_pause(this);
  		clear_buffers(this);
  		spa_alsa_close(this);
  		this->have_format = false;
  	} else {
  		struct spa_audio_info info = { 0 };
  
  		if ((err = spa_format_parse(format, &info.media_type, &info.media_subtype)) < 0)
  			return err;
  
  		if (info.media_type != SPA_MEDIA_TYPE_audio ||
  		    info.media_subtype != SPA_MEDIA_SUBTYPE_raw)
  			return -EINVAL;
  
  		if (spa_format_audio_raw_parse(format, &info.info.raw) < 0)
  			return -EINVAL;
  
  		if ((err = spa_alsa_set_format(this, &info, flags)) < 0)
  			return err;
  
  		this->current_format = info;
  		this->have_format = true;
  	}
  
  	this->info.change_mask |= SPA_NODE_CHANGE_MASK_PROPS;
  	emit_node_info(this, false);
  
  	this->port_info.change_mask |= SPA_PORT_CHANGE_MASK_RATE;
  	this->port_info.rate = SPA_FRACTION(1, this->rate);
  	this->port_info.change_mask |= SPA_PORT_CHANGE_MASK_PARAMS;
  	if (this->have_format) {
  		this->port_params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_READWRITE);
  		this->port_params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, SPA_PARAM_INFO_READ);
  	} else {
  		this->port_params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
  		this->port_params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
  	}
  	emit_port_info(this, false);
  
  	return 0;
  }
  
  static int
  impl_node_port_set_param(void *object,
  			 enum spa_direction direction, uint32_t port_id,
  			 uint32_t id, uint32_t flags,
  			 const struct spa_pod *param)
  {
  	struct state *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	if (id == SPA_PARAM_Format) {
  		return port_set_format(this, direction, port_id, flags, param);
  	}
  	else
  		return -ENOENT;
  }
  
  static int
  impl_node_port_use_buffers(void *object,
  			   enum spa_direction direction, uint32_t port_id,
  			   uint32_t flags,
  			   struct spa_buffer **buffers, uint32_t n_buffers)
  {
  	struct state *this = object;
  	uint32_t i;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	spa_log_debug(this->log, NAME " %p: use %d buffers", this, n_buffers);
  
  	if (!this->have_format)
  		return -EIO;
  
  	if (n_buffers == 0) {
  		spa_alsa_pause(this);
  		clear_buffers(this);
  		return 0;
  	}
  
  	for (i = 0; i < n_buffers; i++) {
  		struct buffer *b = &this->buffers[i];
  		struct spa_data *d = buffers[i]->datas;
  
  		b->buf = buffers[i];
  		b->id = i;
  		b->flags = BUFFER_FLAG_OUT;
  
  		b->h = spa_buffer_find_meta_data(b->buf, SPA_META_Header, sizeof(*b->h));
  
  		if (d[0].data == NULL) {
  			spa_log_error(this->log, NAME " %p: need mapped memory", this);
  			return -EINVAL;
  		}
  		spa_log_debug(this->log, NAME " %p: %d %p data:%p", this, i, b->buf, d[0].data);
  	}
  	this->n_buffers = n_buffers;
  
  	return 0;
  }
  
  static int
  impl_node_port_set_io(void *object,
  		      enum spa_direction direction,
  		      uint32_t port_id,
  		      uint32_t id,
  		      void *data, size_t size)
  {
  	struct state *this = object;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	spa_return_val_if_fail(CHECK_PORT(this, direction, port_id), -EINVAL);
  
  	spa_log_debug(this->log, NAME " %p: io %d %p %zd", this, id, data, size);
  
  	switch (id) {
  	case SPA_IO_Buffers:
  		this->io = data;
  		break;
  	case SPA_IO_RateMatch:
  		this->rate_match = data;
  		break;
  	default:
  		return -ENOENT;
  	}
  	return 0;
  }
  
  static int impl_node_port_reuse_buffer(void *object, uint32_t port_id, uint32_t buffer_id)
  {
  	return -ENOTSUP;
  }
  
  static int impl_node_process(void *object)
  {
  	struct state *this = object;
  	struct spa_io_buffers *input;
  
  	spa_return_val_if_fail(this != NULL, -EINVAL);
  
  	input = this->io;
  	spa_return_val_if_fail(input != NULL, -EIO);
  
  	spa_log_trace_fp(this->log, NAME " %p: process %d %d/%d", this, input->status,
  			input->buffer_id,
  			this->n_buffers);
  
  	if (input->status == SPA_STATUS_HAVE_DATA &&
  	    input->buffer_id < this->n_buffers) {
  		struct buffer *b = &this->buffers[input->buffer_id];
  
  		if (!SPA_FLAG_IS_SET(b->flags, BUFFER_FLAG_OUT)) {
  			spa_log_warn(this->log, NAME " %p: buffer %u in use",
  					this, input->buffer_id);
  			input->status = -EINVAL;
  			return -EINVAL;
  		}
  		spa_log_trace_fp(this->log, NAME " %p: queue buffer %u", this, input->buffer_id);
  		spa_list_append(&this->ready, &b->link);
  		SPA_FLAG_CLEAR(b->flags, BUFFER_FLAG_OUT);
  		input->buffer_id = SPA_ID_INVALID;
  
  		spa_alsa_write(this);
  
  		input->status = SPA_STATUS_OK;
  	}
  	return SPA_STATUS_HAVE_DATA;
  }
  
  static const struct spa_node_methods impl_node = {
  	SPA_VERSION_NODE_METHODS,
  	.add_listener = impl_node_add_listener,
  	.set_callbacks = impl_node_set_callbacks,
  	.sync = impl_node_sync,
  	.enum_params = impl_node_enum_params,
  	.set_param = impl_node_set_param,
  	.set_io = impl_node_set_io,
  	.send_command = impl_node_send_command,
  	.add_port = impl_node_add_port,
  	.remove_port = impl_node_remove_port,
  	.port_enum_params = impl_node_port_enum_params,
  	.port_set_param = impl_node_port_set_param,
  	.port_use_buffers = impl_node_port_use_buffers,
  	.port_set_io = impl_node_port_set_io,
  	.port_reuse_buffer = impl_node_port_reuse_buffer,
  	.process = impl_node_process,
  };
  
  static int impl_get_interface(struct spa_handle *handle, const char *type, void **interface)
  {
  	struct state *this;
  
  	spa_return_val_if_fail(handle != NULL, -EINVAL);
  	spa_return_val_if_fail(interface != NULL, -EINVAL);
  
  	this = (struct state *) handle;
  
  	if (strcmp(type, SPA_TYPE_INTERFACE_Node) == 0)
  		*interface = &this->node;
  	else
  		return -ENOENT;
  
  	return 0;
  }
  
  static int impl_clear(struct spa_handle *handle)
  {
  	struct state *this;
  	spa_return_val_if_fail(handle != NULL, -EINVAL);
  	this = (struct state *) handle;
  	spa_alsa_close(this);
  	return 0;
  }
  
  static size_t
  impl_get_size(const struct spa_handle_factory *factory,
  	      const struct spa_dict *params)
  {
  	return sizeof(struct state);
  }
  
  static int
  impl_init(const struct spa_handle_factory *factory,
  	  struct spa_handle *handle, const struct spa_dict *info, const struct spa_support *support, uint32_t n_support)
  {
  	struct state *this;
  	uint32_t i;
  
  	spa_return_val_if_fail(factory != NULL, -EINVAL);
  	spa_return_val_if_fail(handle != NULL, -EINVAL);
  
  	handle->get_interface = impl_get_interface;
  	handle->clear = impl_clear;
  
  	this = (struct state *) handle;
  
  	this->log = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_Log);
  	this->data_system = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DataSystem);
  	this->data_loop = spa_support_find(support, n_support, SPA_TYPE_INTERFACE_DataLoop);
  
  	if (this->data_loop == NULL) {
  		spa_log_error(this->log, "a data loop is needed");
  		return -EINVAL;
  	}
  	if (this->data_system == NULL) {
  		spa_log_error(this->log, "a data system is needed");
  		return -EINVAL;
  	}
  
  	this->node.iface = SPA_INTERFACE_INIT(
  			SPA_TYPE_INTERFACE_Node,
  			SPA_VERSION_NODE,
  			&impl_node, this);
  
  	spa_hook_list_init(&this->hooks);
  
  	this->stream = SND_PCM_STREAM_PLAYBACK;
  
  	this->info_all = SPA_NODE_CHANGE_MASK_FLAGS |
  			SPA_NODE_CHANGE_MASK_PROPS |
  			SPA_NODE_CHANGE_MASK_PARAMS;
  	this->info = SPA_NODE_INFO_INIT();
  	this->info.max_input_ports = 1;
  	this->info.flags = SPA_NODE_FLAG_RT;
  	this->params[0] = SPA_PARAM_INFO(SPA_PARAM_PropInfo, SPA_PARAM_INFO_READ);
  	this->params[1] = SPA_PARAM_INFO(SPA_PARAM_Props, SPA_PARAM_INFO_READWRITE);
  	this->params[2] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
  	this->info.params = this->params;
  	this->info.n_params = 3;
  
  	reset_props(&this->props);
  
  	this->port_info_all = SPA_PORT_CHANGE_MASK_FLAGS |
  				 SPA_PORT_CHANGE_MASK_PARAMS;
  	this->port_info = SPA_PORT_INFO_INIT();
  	this->port_info.flags = SPA_PORT_FLAG_LIVE |
  			   SPA_PORT_FLAG_PHYSICAL |
  			   SPA_PORT_FLAG_TERMINAL;
  	this->port_params[0] = SPA_PARAM_INFO(SPA_PARAM_EnumFormat, SPA_PARAM_INFO_READ);
  	this->port_params[1] = SPA_PARAM_INFO(SPA_PARAM_Meta, SPA_PARAM_INFO_READ);
  	this->port_params[2] = SPA_PARAM_INFO(SPA_PARAM_IO, SPA_PARAM_INFO_READ);
  	this->port_params[3] = SPA_PARAM_INFO(SPA_PARAM_Format, SPA_PARAM_INFO_WRITE);
  	this->port_params[4] = SPA_PARAM_INFO(SPA_PARAM_Buffers, 0);
  	this->port_info.params = this->port_params;
  	this->port_info.n_params = 5;
  
  	spa_list_init(&this->ready);
  
  	snd_config_update_free_global();
  
  	for (i = 0; info && i < info->n_items; i++) {
  		const char *s = info->items[i].value;
  		if (!strcmp(info->items[i].key, SPA_KEY_API_ALSA_PATH)) {
  			snprintf(this->props.device, 63, "%s", info->items[i].value);
  		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_CHANNELS)) {
  			this->default_channels = atoi(info->items[i].value);
  		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_RATE)) {
  			this->default_rate = atoi(info->items[i].value);
  		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_FORMAT)) {
  			this->default_format = spa_alsa_format_from_name(info->items[i].value, 128);
  		} else if (!strcmp(info->items[i].key, SPA_KEY_AUDIO_POSITION)) {
  			size_t len;
  			while (*s && this->default_pos.channels < SPA_AUDIO_MAX_CHANNELS) {
  				if ((len = strcspn(s, ",")) == 0)
  					break;
  				this->default_pos.pos[this->default_pos.channels++] =
  					spa_alsa_channel_from_name(s, len);
  				s += len + strspn(s+len, ",");
  			}
  		} else if (!strcmp(info->items[i].key, "api.alsa.period-size")) {
  			this->default_period_size = atoi(info->items[i].value);
  		} else if (!strcmp(info->items[i].key, "api.alsa.headroom")) {
  			this->default_headroom = atoi(info->items[i].value);
  		} else if (!strcmp(info->items[i].key, "api.alsa.disable-mmap")) {
  			this->disable_mmap = (strcmp(s, "true") == 0 || atoi(s) == 1);
  		} else if (!strcmp(info->items[i].key, "api.alsa.disable-batch")) {
  			this->disable_batch = (strcmp(s, "true") == 0 || atoi(s) == 1);
  		} else if (!strcmp(info->items[i].key, "api.alsa.use-chmap")) {
  			this->props.use_chmap = (strcmp(s, "true") == 0 || atoi(s) == 1);
  		}
  	}
  	return 0;
  }
  
  static const struct spa_interface_info impl_interfaces[] = {
  	{SPA_TYPE_INTERFACE_Node,},
  };
  
  static int
  impl_enum_interface_info(const struct spa_handle_factory *factory,
  			 const struct spa_interface_info **info, uint32_t *index)
  {
  	spa_return_val_if_fail(factory != NULL, -EINVAL);
  	spa_return_val_if_fail(info != NULL, -EINVAL);
  	spa_return_val_if_fail(index != NULL, -EINVAL);
  
  	switch (*index) {
  	case 0:
  		*info = &impl_interfaces[*index];
  		break;
  	default:
  		return 0;
  	}
  	(*index)++;
  	return 1;
  }
  
  static const struct spa_dict_item info_items[] = {
  	{ SPA_KEY_FACTORY_AUTHOR, "Wim Taymans <wim.taymans@gmail.com>" },
  	{ SPA_KEY_FACTORY_DESCRIPTION, "Play audio with the alsa API" },
  	{ SPA_KEY_FACTORY_USAGE, "["SPA_KEY_API_ALSA_PATH"=<path>]" },
  };
  
  static const struct spa_dict info = SPA_DICT_INIT_ARRAY(info_items);
  
  const struct spa_handle_factory spa_alsa_sink_factory = {
  	SPA_VERSION_HANDLE_FACTORY,
  	SPA_NAME_API_ALSA_PCM_SINK,
  	&info,
  	impl_get_size,
  	impl_init,
  	impl_enum_interface_info,
  };
  