1/***
2  This file is part of PulseAudio.
3
4  Copyright 2004-2008 Lennart Poettering
5  Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
6
7  PulseAudio is free software; you can redistribute it and/or modify
8  it under the terms of the GNU Lesser General Public License as published
9  by the Free Software Foundation; either version 2 of the License,
10  or (at your option) any later version.
11
12  PulseAudio is distributed in the hope that it will be useful, but
13  WITHOUT ANY WARRANTY; without even the implied warranty of
14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  General Public License for more details.
16
17  You should have received a copy of the GNU Lesser General Public License
18  along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
19***/
20
21#ifdef HAVE_CONFIG_H
22#include <config.h>
23#endif
24
25#include <stdlib.h>
26#include <stdio.h>
27#include <errno.h>
28#include <unistd.h>
29
30#include <pulse/rtclock.h>
31#include <pulse/timeval.h>
32#include <pulse/util.h>
33#include <pulse/xmalloc.h>
34
35#include <pulsecore/core-util.h>
36#include <pulsecore/log.h>
37#include <pulsecore/macro.h>
38#include <pulsecore/modargs.h>
39#include <pulsecore/module.h>
40#include <pulsecore/rtpoll.h>
41#include <pulsecore/source.h>
42#include <pulsecore/thread-mq.h>
43#include <pulsecore/thread.h>
44
45PA_MODULE_AUTHOR("Lennart Poettering & Marc-Andre Lureau");
46PA_MODULE_DESCRIPTION("Clocked NULL source");
47PA_MODULE_VERSION(PACKAGE_VERSION);
48PA_MODULE_LOAD_ONCE(false);
49PA_MODULE_USAGE(
50        "format=<sample format> "
51        "channels=<number of channels> "
52        "rate=<sample rate> "
53        "source_name=<name of source> "
54        "channel_map=<channel map> "
55        "max_latency_msec=<maximum latency in ms> "
56        "description=<description for the source> ");
57
58#define DEFAULT_SOURCE_NAME "source.null"
59#define MAX_LATENCY_USEC (PA_USEC_PER_SEC * 2)
60#define MIN_LATENCY_USEC (500)
61
62struct userdata {
63    pa_core *core;
64    pa_module *module;
65    pa_source *source;
66
67    pa_thread *thread;
68    pa_thread_mq thread_mq;
69    pa_rtpoll *rtpoll;
70
71    size_t block_size;
72
73    pa_usec_t block_usec;
74    pa_usec_t timestamp;
75};
76
77static const char* const valid_modargs[] = {
78    "rate",
79    "format",
80    "channels",
81    "source_name",
82    "channel_map",
83    "max_latency_msec",
84    "description",
85    NULL
86};
87
88static int source_process_msg(pa_msgobject *o, int code, void *data, int64_t offset, pa_memchunk *chunk) {
89    struct userdata *u = PA_SOURCE(o)->userdata;
90
91    switch (code) {
92        case PA_SOURCE_MESSAGE_GET_LATENCY: {
93            pa_usec_t now;
94
95            now = pa_rtclock_now();
96            *((int64_t*) data) = (int64_t)now - (int64_t)u->timestamp;
97
98            return 0;
99        }
100    }
101
102    return pa_source_process_msg(o, code, data, offset, chunk);
103}
104
105/* Called from the IO thread. */
106static int source_set_state_in_io_thread_cb(pa_source *s, pa_source_state_t new_state, pa_suspend_cause_t new_suspend_cause) {
107    struct userdata *u;
108
109    pa_assert(s);
110    pa_assert_se(u = s->userdata);
111
112    if (s->thread_info.state == PA_SOURCE_SUSPENDED || s->thread_info.state == PA_SOURCE_INIT) {
113        if (PA_SOURCE_IS_OPENED(new_state))
114            u->timestamp = pa_rtclock_now();
115    }
116
117    return 0;
118}
119
120static void source_update_requested_latency_cb(pa_source *s) {
121    struct userdata *u;
122
123    pa_source_assert_ref(s);
124    u = s->userdata;
125    pa_assert(u);
126
127    u->block_usec = pa_source_get_requested_latency_within_thread(s);
128
129    if (u->block_usec == (pa_usec_t)-1)
130        u->block_usec = u->source->thread_info.max_latency;
131
132    pa_source_set_max_rewind_within_thread(s, pa_usec_to_bytes(u->block_usec, &u->source->sample_spec));
133}
134
135static void thread_func(void *userdata) {
136    struct userdata *u = userdata;
137    bool timer_elapsed = false;
138    size_t max_block_size;
139
140    pa_assert(u);
141
142    pa_log_debug("Thread starting up");
143
144    if (u->core->realtime_scheduling)
145        pa_thread_make_realtime(u->core->realtime_priority);
146
147    pa_thread_mq_install(&u->thread_mq);
148
149    max_block_size = pa_frame_align(pa_mempool_block_size_max(u->core->mempool), &u->source->sample_spec);
150    u->timestamp = pa_rtclock_now();
151
152    for (;;) {
153        int ret;
154
155        /* Generate some null data */
156        if (PA_SOURCE_IS_OPENED(u->source->thread_info.state)) {
157            pa_usec_t now;
158            pa_memchunk chunk;
159
160            now = pa_rtclock_now();
161
162            if (timer_elapsed && (chunk.length = pa_usec_to_bytes(now - u->timestamp, &u->source->sample_spec)) > 0) {
163
164                chunk.length = PA_MIN(max_block_size, chunk.length);
165
166                chunk.memblock = pa_memblock_new(u->core->mempool, chunk.length);
167                chunk.index = 0;
168                pa_silence_memchunk(&chunk, &u->source->sample_spec);
169                pa_source_post(u->source, &chunk);
170                pa_memblock_unref(chunk.memblock);
171
172                u->timestamp += pa_bytes_to_usec(chunk.length, &u->source->sample_spec);
173            }
174
175            pa_rtpoll_set_timer_absolute(u->rtpoll, u->timestamp + u->block_usec);
176        } else
177            pa_rtpoll_set_timer_disabled(u->rtpoll);
178
179        /* Hmm, nothing to do. Let's sleep */
180        if ((ret = pa_rtpoll_run(u->rtpoll)) < 0)
181            goto fail;
182
183        timer_elapsed = pa_rtpoll_timer_elapsed(u->rtpoll);
184
185        if (ret == 0)
186            goto finish;
187    }
188
189fail:
190    /* If this was no regular exit from the loop we have to continue
191     * processing messages until we received PA_MESSAGE_SHUTDOWN */
192    pa_asyncmsgq_post(u->thread_mq.outq, PA_MSGOBJECT(u->core), PA_CORE_MESSAGE_UNLOAD_MODULE, u->module, 0, NULL, NULL);
193    pa_asyncmsgq_wait_for(u->thread_mq.inq, PA_MESSAGE_SHUTDOWN);
194
195finish:
196    pa_log_debug("Thread shutting down");
197}
198
199int pa__init(pa_module*m) {
200    struct userdata *u = NULL;
201    pa_sample_spec ss;
202    pa_channel_map map;
203    pa_modargs *ma = NULL;
204    pa_source_new_data data;
205    uint32_t max_latency_msec;
206
207    pa_assert(m);
208
209    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
210        pa_log("Failed to parse module arguments.");
211        goto fail;
212    }
213
214    ss = m->core->default_sample_spec;
215    map = m->core->default_channel_map;
216    if (pa_modargs_get_sample_spec_and_channel_map(ma, &ss, &map, PA_CHANNEL_MAP_DEFAULT) < 0) {
217        pa_log("Invalid sample format specification or channel map");
218        goto fail;
219    }
220
221    m->userdata = u = pa_xnew0(struct userdata, 1);
222    u->core = m->core;
223    u->module = m;
224    u->rtpoll = pa_rtpoll_new();
225
226    if (pa_thread_mq_init(&u->thread_mq, m->core->mainloop, u->rtpoll) < 0) {
227        pa_log("pa_thread_mq_init() failed.");
228        goto fail;
229    }
230
231    pa_source_new_data_init(&data);
232    data.driver = __FILE__;
233    data.module = m;
234    pa_source_new_data_set_name(&data, pa_modargs_get_value(ma, "source_name", DEFAULT_SOURCE_NAME));
235    pa_source_new_data_set_sample_spec(&data, &ss);
236    pa_source_new_data_set_channel_map(&data, &map);
237    pa_proplist_sets(data.proplist, PA_PROP_DEVICE_DESCRIPTION, pa_modargs_get_value(ma, "description", "Null Input"));
238    pa_proplist_sets(data.proplist, PA_PROP_DEVICE_CLASS, "abstract");
239
240    u->source = pa_source_new(m->core, &data, PA_SOURCE_LATENCY | PA_SOURCE_DYNAMIC_LATENCY);
241    pa_source_new_data_done(&data);
242
243    if (!u->source) {
244        pa_log("Failed to create source object.");
245        goto fail;
246    }
247
248    u->source->parent.process_msg = source_process_msg;
249    u->source->set_state_in_io_thread = source_set_state_in_io_thread_cb;
250    u->source->update_requested_latency = source_update_requested_latency_cb;
251    u->source->userdata = u;
252
253    pa_source_set_asyncmsgq(u->source, u->thread_mq.inq);
254    pa_source_set_rtpoll(u->source, u->rtpoll);
255
256    max_latency_msec = MAX_LATENCY_USEC / PA_USEC_PER_MSEC;
257    if (pa_modargs_get_value_u32(ma, "max_latency_msec", &max_latency_msec) < 0) {
258        pa_log("Failed to get max_latency_msec.");
259        goto fail;
260    }
261
262    pa_source_set_latency_range(u->source, MIN_LATENCY_USEC, max_latency_msec * PA_USEC_PER_MSEC);
263
264    u->block_usec = u->source->thread_info.max_latency;
265
266    u->source->thread_info.max_rewind =
267        pa_usec_to_bytes(u->block_usec, &u->source->sample_spec);
268
269    if (!(u->thread = pa_thread_new("null-source", thread_func, u))) {
270        pa_log("Failed to create thread.");
271        goto fail;
272    }
273
274    pa_source_put(u->source);
275
276    pa_modargs_free(ma);
277
278    return 0;
279
280fail:
281    if (ma)
282        pa_modargs_free(ma);
283
284    pa__done(m);
285
286    return -1;
287}
288
289void pa__done(pa_module*m) {
290    struct userdata *u;
291
292    pa_assert(m);
293
294    if (!(u = m->userdata))
295        return;
296
297    if (u->source)
298        pa_source_unlink(u->source);
299
300    if (u->thread) {
301        pa_asyncmsgq_send(u->thread_mq.inq, NULL, PA_MESSAGE_SHUTDOWN, NULL, 0, NULL);
302        pa_thread_free(u->thread);
303    }
304
305    pa_thread_mq_done(&u->thread_mq);
306
307    if (u->source)
308        pa_source_unref(u->source);
309
310    if (u->rtpoll)
311        pa_rtpoll_free(u->rtpoll);
312
313    pa_xfree(u);
314}
315