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axmol/thirdparty/openal/alc/backends/alsa.cpp

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/**
* OpenAL cross platform audio library
* Copyright (C) 1999-2007 by authors.
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
* Or go to http://www.gnu.org/copyleft/lgpl.html
*/
#include "config.h"
#include "alsa.h"
#include <algorithm>
#include <atomic>
#include <cassert>
#include <cerrno>
#include <chrono>
#include <cstring>
#include <exception>
#include <functional>
#include <memory>
#include <mutex>
#include <string>
#include <thread>
#include <utility>
#include <vector>
#include "albit.h"
#include "alc/alconfig.h"
#include "almalloc.h"
#include "alnumeric.h"
#include "althrd_setname.h"
#include "core/device.h"
#include "core/helpers.h"
#include "core/logging.h"
#include "dynload.h"
#include "ringbuffer.h"
#include <alsa/asoundlib.h>
namespace {
constexpr char alsaDevice[] = "ALSA Default";
#ifdef HAVE_DYNLOAD
#define ALSA_FUNCS(MAGIC) \
MAGIC(snd_strerror); \
MAGIC(snd_pcm_open); \
MAGIC(snd_pcm_close); \
MAGIC(snd_pcm_nonblock); \
MAGIC(snd_pcm_frames_to_bytes); \
MAGIC(snd_pcm_bytes_to_frames); \
MAGIC(snd_pcm_hw_params_malloc); \
MAGIC(snd_pcm_hw_params_free); \
MAGIC(snd_pcm_hw_params_any); \
MAGIC(snd_pcm_hw_params_current); \
MAGIC(snd_pcm_hw_params_get_access); \
MAGIC(snd_pcm_hw_params_get_buffer_size); \
MAGIC(snd_pcm_hw_params_get_buffer_time_min); \
MAGIC(snd_pcm_hw_params_get_buffer_time_max); \
MAGIC(snd_pcm_hw_params_get_channels); \
MAGIC(snd_pcm_hw_params_get_period_size); \
MAGIC(snd_pcm_hw_params_get_period_time_max); \
MAGIC(snd_pcm_hw_params_get_period_time_min); \
MAGIC(snd_pcm_hw_params_get_periods); \
MAGIC(snd_pcm_hw_params_set_access); \
MAGIC(snd_pcm_hw_params_set_buffer_size_min); \
MAGIC(snd_pcm_hw_params_set_buffer_size_near); \
MAGIC(snd_pcm_hw_params_set_buffer_time_near); \
MAGIC(snd_pcm_hw_params_set_channels); \
MAGIC(snd_pcm_hw_params_set_channels_near); \
MAGIC(snd_pcm_hw_params_set_format); \
MAGIC(snd_pcm_hw_params_set_period_time_near); \
MAGIC(snd_pcm_hw_params_set_period_size_near); \
MAGIC(snd_pcm_hw_params_set_periods_near); \
MAGIC(snd_pcm_hw_params_set_rate_near); \
MAGIC(snd_pcm_hw_params_set_rate); \
MAGIC(snd_pcm_hw_params_set_rate_resample); \
MAGIC(snd_pcm_hw_params_test_format); \
MAGIC(snd_pcm_hw_params_test_channels); \
MAGIC(snd_pcm_hw_params); \
MAGIC(snd_pcm_sw_params); \
MAGIC(snd_pcm_sw_params_current); \
MAGIC(snd_pcm_sw_params_free); \
MAGIC(snd_pcm_sw_params_malloc); \
MAGIC(snd_pcm_sw_params_set_avail_min); \
MAGIC(snd_pcm_sw_params_set_stop_threshold); \
MAGIC(snd_pcm_prepare); \
MAGIC(snd_pcm_start); \
MAGIC(snd_pcm_resume); \
MAGIC(snd_pcm_reset); \
MAGIC(snd_pcm_wait); \
MAGIC(snd_pcm_delay); \
MAGIC(snd_pcm_state); \
MAGIC(snd_pcm_avail_update); \
MAGIC(snd_pcm_mmap_begin); \
MAGIC(snd_pcm_mmap_commit); \
MAGIC(snd_pcm_readi); \
MAGIC(snd_pcm_writei); \
MAGIC(snd_pcm_drain); \
MAGIC(snd_pcm_drop); \
MAGIC(snd_pcm_recover); \
MAGIC(snd_pcm_info_malloc); \
MAGIC(snd_pcm_info_free); \
MAGIC(snd_pcm_info_set_device); \
MAGIC(snd_pcm_info_set_subdevice); \
MAGIC(snd_pcm_info_set_stream); \
MAGIC(snd_pcm_info_get_name); \
MAGIC(snd_ctl_pcm_next_device); \
MAGIC(snd_ctl_pcm_info); \
MAGIC(snd_ctl_open); \
MAGIC(snd_ctl_close); \
MAGIC(snd_ctl_card_info_malloc); \
MAGIC(snd_ctl_card_info_free); \
MAGIC(snd_ctl_card_info); \
MAGIC(snd_ctl_card_info_get_name); \
MAGIC(snd_ctl_card_info_get_id); \
MAGIC(snd_card_next); \
MAGIC(snd_config_update_free_global)
void *alsa_handle;
#define MAKE_FUNC(f) decltype(f) * p##f
ALSA_FUNCS(MAKE_FUNC);
#undef MAKE_FUNC
#ifndef IN_IDE_PARSER
#define snd_strerror psnd_strerror
#define snd_pcm_open psnd_pcm_open
#define snd_pcm_close psnd_pcm_close
#define snd_pcm_nonblock psnd_pcm_nonblock
#define snd_pcm_frames_to_bytes psnd_pcm_frames_to_bytes
#define snd_pcm_bytes_to_frames psnd_pcm_bytes_to_frames
#define snd_pcm_hw_params_malloc psnd_pcm_hw_params_malloc
#define snd_pcm_hw_params_free psnd_pcm_hw_params_free
#define snd_pcm_hw_params_any psnd_pcm_hw_params_any
#define snd_pcm_hw_params_current psnd_pcm_hw_params_current
#define snd_pcm_hw_params_set_access psnd_pcm_hw_params_set_access
#define snd_pcm_hw_params_set_format psnd_pcm_hw_params_set_format
#define snd_pcm_hw_params_set_channels psnd_pcm_hw_params_set_channels
#define snd_pcm_hw_params_set_channels_near psnd_pcm_hw_params_set_channels_near
#define snd_pcm_hw_params_set_periods_near psnd_pcm_hw_params_set_periods_near
#define snd_pcm_hw_params_set_rate_near psnd_pcm_hw_params_set_rate_near
#define snd_pcm_hw_params_set_rate psnd_pcm_hw_params_set_rate
#define snd_pcm_hw_params_set_rate_resample psnd_pcm_hw_params_set_rate_resample
#define snd_pcm_hw_params_set_buffer_time_near psnd_pcm_hw_params_set_buffer_time_near
#define snd_pcm_hw_params_set_period_time_near psnd_pcm_hw_params_set_period_time_near
#define snd_pcm_hw_params_set_buffer_size_near psnd_pcm_hw_params_set_buffer_size_near
#define snd_pcm_hw_params_set_period_size_near psnd_pcm_hw_params_set_period_size_near
#define snd_pcm_hw_params_set_buffer_size_min psnd_pcm_hw_params_set_buffer_size_min
#define snd_pcm_hw_params_get_buffer_time_min psnd_pcm_hw_params_get_buffer_time_min
#define snd_pcm_hw_params_get_buffer_time_max psnd_pcm_hw_params_get_buffer_time_max
#define snd_pcm_hw_params_get_period_time_min psnd_pcm_hw_params_get_period_time_min
#define snd_pcm_hw_params_get_period_time_max psnd_pcm_hw_params_get_period_time_max
#define snd_pcm_hw_params_get_buffer_size psnd_pcm_hw_params_get_buffer_size
#define snd_pcm_hw_params_get_period_size psnd_pcm_hw_params_get_period_size
#define snd_pcm_hw_params_get_access psnd_pcm_hw_params_get_access
#define snd_pcm_hw_params_get_periods psnd_pcm_hw_params_get_periods
#define snd_pcm_hw_params_get_channels psnd_pcm_hw_params_get_channels
#define snd_pcm_hw_params_test_format psnd_pcm_hw_params_test_format
#define snd_pcm_hw_params_test_channels psnd_pcm_hw_params_test_channels
#define snd_pcm_hw_params psnd_pcm_hw_params
#define snd_pcm_sw_params_malloc psnd_pcm_sw_params_malloc
#define snd_pcm_sw_params_current psnd_pcm_sw_params_current
#define snd_pcm_sw_params_set_avail_min psnd_pcm_sw_params_set_avail_min
#define snd_pcm_sw_params_set_stop_threshold psnd_pcm_sw_params_set_stop_threshold
#define snd_pcm_sw_params psnd_pcm_sw_params
#define snd_pcm_sw_params_free psnd_pcm_sw_params_free
#define snd_pcm_prepare psnd_pcm_prepare
#define snd_pcm_start psnd_pcm_start
#define snd_pcm_resume psnd_pcm_resume
#define snd_pcm_reset psnd_pcm_reset
#define snd_pcm_wait psnd_pcm_wait
#define snd_pcm_delay psnd_pcm_delay
#define snd_pcm_state psnd_pcm_state
#define snd_pcm_avail_update psnd_pcm_avail_update
#define snd_pcm_mmap_begin psnd_pcm_mmap_begin
#define snd_pcm_mmap_commit psnd_pcm_mmap_commit
#define snd_pcm_readi psnd_pcm_readi
#define snd_pcm_writei psnd_pcm_writei
#define snd_pcm_drain psnd_pcm_drain
#define snd_pcm_drop psnd_pcm_drop
#define snd_pcm_recover psnd_pcm_recover
#define snd_pcm_info_malloc psnd_pcm_info_malloc
#define snd_pcm_info_free psnd_pcm_info_free
#define snd_pcm_info_set_device psnd_pcm_info_set_device
#define snd_pcm_info_set_subdevice psnd_pcm_info_set_subdevice
#define snd_pcm_info_set_stream psnd_pcm_info_set_stream
#define snd_pcm_info_get_name psnd_pcm_info_get_name
#define snd_ctl_pcm_next_device psnd_ctl_pcm_next_device
#define snd_ctl_pcm_info psnd_ctl_pcm_info
#define snd_ctl_open psnd_ctl_open
#define snd_ctl_close psnd_ctl_close
#define snd_ctl_card_info_malloc psnd_ctl_card_info_malloc
#define snd_ctl_card_info_free psnd_ctl_card_info_free
#define snd_ctl_card_info psnd_ctl_card_info
#define snd_ctl_card_info_get_name psnd_ctl_card_info_get_name
#define snd_ctl_card_info_get_id psnd_ctl_card_info_get_id
#define snd_card_next psnd_card_next
#define snd_config_update_free_global psnd_config_update_free_global
#endif
#endif
struct HwParamsDeleter {
void operator()(snd_pcm_hw_params_t *ptr) { snd_pcm_hw_params_free(ptr); }
};
using HwParamsPtr = std::unique_ptr<snd_pcm_hw_params_t,HwParamsDeleter>;
HwParamsPtr CreateHwParams()
{
snd_pcm_hw_params_t *hp{};
snd_pcm_hw_params_malloc(&hp);
return HwParamsPtr{hp};
}
struct SwParamsDeleter {
void operator()(snd_pcm_sw_params_t *ptr) { snd_pcm_sw_params_free(ptr); }
};
using SwParamsPtr = std::unique_ptr<snd_pcm_sw_params_t,SwParamsDeleter>;
SwParamsPtr CreateSwParams()
{
snd_pcm_sw_params_t *sp{};
snd_pcm_sw_params_malloc(&sp);
return SwParamsPtr{sp};
}
struct DevMap {
std::string name;
std::string device_name;
template<typename T, typename U>
DevMap(T&& name_, U&& devname)
: name{std::forward<T>(name_)}, device_name{std::forward<U>(devname)}
{ }
};
std::vector<DevMap> PlaybackDevices;
std::vector<DevMap> CaptureDevices;
const char *prefix_name(snd_pcm_stream_t stream)
{
assert(stream == SND_PCM_STREAM_PLAYBACK || stream == SND_PCM_STREAM_CAPTURE);
return (stream==SND_PCM_STREAM_PLAYBACK) ? "device-prefix" : "capture-prefix";
}
std::vector<DevMap> probe_devices(snd_pcm_stream_t stream)
{
std::vector<DevMap> devlist;
snd_ctl_card_info_t *info;
snd_ctl_card_info_malloc(&info);
snd_pcm_info_t *pcminfo;
snd_pcm_info_malloc(&pcminfo);
auto defname = ConfigValueStr(nullptr, "alsa",
(stream == SND_PCM_STREAM_PLAYBACK) ? "device" : "capture");
devlist.emplace_back(alsaDevice, defname ? defname->c_str() : "default");
if(auto customdevs = ConfigValueStr(nullptr, "alsa",
(stream == SND_PCM_STREAM_PLAYBACK) ? "custom-devices" : "custom-captures"))
{
size_t nextpos{customdevs->find_first_not_of(';')};
size_t curpos;
while((curpos=nextpos) < customdevs->length())
{
nextpos = customdevs->find_first_of(';', curpos+1);
size_t seppos{customdevs->find_first_of('=', curpos)};
if(seppos == curpos || seppos >= nextpos)
{
std::string spec{customdevs->substr(curpos, nextpos-curpos)};
ERR("Invalid ALSA device specification \"%s\"\n", spec.c_str());
}
else
{
devlist.emplace_back(customdevs->substr(curpos, seppos-curpos),
customdevs->substr(seppos+1, nextpos-seppos-1));
const auto &entry = devlist.back();
TRACE("Got device \"%s\", \"%s\"\n", entry.name.c_str(), entry.device_name.c_str());
}
if(nextpos < customdevs->length())
nextpos = customdevs->find_first_not_of(';', nextpos+1);
}
}
const std::string main_prefix{
ConfigValueStr(nullptr, "alsa", prefix_name(stream)).value_or("plughw:")};
int card{-1};
int err{snd_card_next(&card)};
for(;err >= 0 && card >= 0;err = snd_card_next(&card))
{
std::string name{"hw:" + std::to_string(card)};
snd_ctl_t *handle;
if((err=snd_ctl_open(&handle, name.c_str(), 0)) < 0)
{
ERR("control open (hw:%d): %s\n", card, snd_strerror(err));
continue;
}
if((err=snd_ctl_card_info(handle, info)) < 0)
{
ERR("control hardware info (hw:%d): %s\n", card, snd_strerror(err));
snd_ctl_close(handle);
continue;
}
const char *cardname{snd_ctl_card_info_get_name(info)};
const char *cardid{snd_ctl_card_info_get_id(info)};
name = prefix_name(stream);
name += '-';
name += cardid;
const std::string card_prefix{
ConfigValueStr(nullptr, "alsa", name.c_str()).value_or(main_prefix)};
int dev{-1};
while(true)
{
if(snd_ctl_pcm_next_device(handle, &dev) < 0)
ERR("snd_ctl_pcm_next_device failed\n");
if(dev < 0) break;
snd_pcm_info_set_device(pcminfo, static_cast<uint>(dev));
snd_pcm_info_set_subdevice(pcminfo, 0);
snd_pcm_info_set_stream(pcminfo, stream);
if((err=snd_ctl_pcm_info(handle, pcminfo)) < 0)
{
if(err != -ENOENT)
ERR("control digital audio info (hw:%d): %s\n", card, snd_strerror(err));
continue;
}
/* "prefix-cardid-dev" */
name = prefix_name(stream);
name += '-';
name += cardid;
name += '-';
name += std::to_string(dev);
const std::string device_prefix{
ConfigValueStr(nullptr, "alsa", name.c_str()).value_or(card_prefix)};
/* "CardName, PcmName (CARD=cardid,DEV=dev)" */
name = cardname;
name += ", ";
name += snd_pcm_info_get_name(pcminfo);
name += " (CARD=";
name += cardid;
name += ",DEV=";
name += std::to_string(dev);
name += ')';
/* "devprefixCARD=cardid,DEV=dev" */
std::string device{device_prefix};
device += "CARD=";
device += cardid;
device += ",DEV=";
device += std::to_string(dev);
devlist.emplace_back(std::move(name), std::move(device));
const auto &entry = devlist.back();
TRACE("Got device \"%s\", \"%s\"\n", entry.name.c_str(), entry.device_name.c_str());
}
snd_ctl_close(handle);
}
if(err < 0)
ERR("snd_card_next failed: %s\n", snd_strerror(err));
snd_pcm_info_free(pcminfo);
snd_ctl_card_info_free(info);
return devlist;
}
int verify_state(snd_pcm_t *handle)
{
snd_pcm_state_t state{snd_pcm_state(handle)};
int err;
switch(state)
{
case SND_PCM_STATE_OPEN:
case SND_PCM_STATE_SETUP:
case SND_PCM_STATE_PREPARED:
case SND_PCM_STATE_RUNNING:
case SND_PCM_STATE_DRAINING:
case SND_PCM_STATE_PAUSED:
/* All Okay */
break;
case SND_PCM_STATE_XRUN:
if((err=snd_pcm_recover(handle, -EPIPE, 1)) < 0)
return err;
break;
case SND_PCM_STATE_SUSPENDED:
if((err=snd_pcm_recover(handle, -ESTRPIPE, 1)) < 0)
return err;
break;
case SND_PCM_STATE_DISCONNECTED:
return -ENODEV;
}
return state;
}
struct AlsaPlayback final : public BackendBase {
AlsaPlayback(DeviceBase *device) noexcept : BackendBase{device} { }
~AlsaPlayback() override;
int mixerProc();
int mixerNoMMapProc();
void open(std::string_view name) override;
bool reset() override;
void start() override;
void stop() override;
ClockLatency getClockLatency() override;
snd_pcm_t *mPcmHandle{nullptr};
std::mutex mMutex;
uint mFrameStep{};
std::vector<std::byte> mBuffer;
std::atomic<bool> mKillNow{true};
std::thread mThread;
DEF_NEWDEL(AlsaPlayback)
};
AlsaPlayback::~AlsaPlayback()
{
if(mPcmHandle)
snd_pcm_close(mPcmHandle);
mPcmHandle = nullptr;
}
int AlsaPlayback::mixerProc()
{
SetRTPriority();
althrd_setname(MIXER_THREAD_NAME);
const snd_pcm_uframes_t update_size{mDevice->UpdateSize};
const snd_pcm_uframes_t buffer_size{mDevice->BufferSize};
while(!mKillNow.load(std::memory_order_acquire))
{
int state{verify_state(mPcmHandle)};
if(state < 0)
{
ERR("Invalid state detected: %s\n", snd_strerror(state));
mDevice->handleDisconnect("Bad state: %s", snd_strerror(state));
break;
}
snd_pcm_sframes_t avails{snd_pcm_avail_update(mPcmHandle)};
if(avails < 0)
{
ERR("available update failed: %s\n", snd_strerror(static_cast<int>(avails)));
continue;
}
snd_pcm_uframes_t avail{static_cast<snd_pcm_uframes_t>(avails)};
if(avail > buffer_size)
{
WARN("available samples exceeds the buffer size\n");
snd_pcm_reset(mPcmHandle);
continue;
}
// make sure there's frames to process
if(avail < update_size)
{
if(state != SND_PCM_STATE_RUNNING)
{
int err{snd_pcm_start(mPcmHandle)};
if(err < 0)
{
ERR("start failed: %s\n", snd_strerror(err));
continue;
}
}
if(snd_pcm_wait(mPcmHandle, 1000) == 0)
ERR("Wait timeout... buffer size too low?\n");
continue;
}
avail -= avail%update_size;
// it is possible that contiguous areas are smaller, thus we use a loop
std::lock_guard<std::mutex> _{mMutex};
while(avail > 0)
{
snd_pcm_uframes_t frames{avail};
const snd_pcm_channel_area_t *areas{};
snd_pcm_uframes_t offset{};
int err{snd_pcm_mmap_begin(mPcmHandle, &areas, &offset, &frames)};
if(err < 0)
{
ERR("mmap begin error: %s\n", snd_strerror(err));
break;
}
char *WritePtr{static_cast<char*>(areas->addr) + (offset * areas->step / 8)};
mDevice->renderSamples(WritePtr, static_cast<uint>(frames), mFrameStep);
snd_pcm_sframes_t commitres{snd_pcm_mmap_commit(mPcmHandle, offset, frames)};
if(commitres < 0 || static_cast<snd_pcm_uframes_t>(commitres) != frames)
{
ERR("mmap commit error: %s\n",
snd_strerror(commitres >= 0 ? -EPIPE : static_cast<int>(commitres)));
break;
}
avail -= frames;
}
}
return 0;
}
int AlsaPlayback::mixerNoMMapProc()
{
SetRTPriority();
althrd_setname(MIXER_THREAD_NAME);
const snd_pcm_uframes_t update_size{mDevice->UpdateSize};
const snd_pcm_uframes_t buffer_size{mDevice->BufferSize};
while(!mKillNow.load(std::memory_order_acquire))
{
int state{verify_state(mPcmHandle)};
if(state < 0)
{
ERR("Invalid state detected: %s\n", snd_strerror(state));
mDevice->handleDisconnect("Bad state: %s", snd_strerror(state));
break;
}
snd_pcm_sframes_t avail{snd_pcm_avail_update(mPcmHandle)};
if(avail < 0)
{
ERR("available update failed: %s\n", snd_strerror(static_cast<int>(avail)));
continue;
}
if(static_cast<snd_pcm_uframes_t>(avail) > buffer_size)
{
WARN("available samples exceeds the buffer size\n");
snd_pcm_reset(mPcmHandle);
continue;
}
if(static_cast<snd_pcm_uframes_t>(avail) < update_size)
{
if(state != SND_PCM_STATE_RUNNING)
{
int err{snd_pcm_start(mPcmHandle)};
if(err < 0)
{
ERR("start failed: %s\n", snd_strerror(err));
continue;
}
}
if(snd_pcm_wait(mPcmHandle, 1000) == 0)
ERR("Wait timeout... buffer size too low?\n");
continue;
}
std::byte *WritePtr{mBuffer.data()};
avail = snd_pcm_bytes_to_frames(mPcmHandle, static_cast<ssize_t>(mBuffer.size()));
std::lock_guard<std::mutex> _{mMutex};
mDevice->renderSamples(WritePtr, static_cast<uint>(avail), mFrameStep);
while(avail > 0)
{
snd_pcm_sframes_t ret{snd_pcm_writei(mPcmHandle, WritePtr,
static_cast<snd_pcm_uframes_t>(avail))};
switch(ret)
{
case -EAGAIN:
continue;
#if ESTRPIPE != EPIPE
case -ESTRPIPE:
#endif
case -EPIPE:
case -EINTR:
ret = snd_pcm_recover(mPcmHandle, static_cast<int>(ret), 1);
if(ret < 0)
avail = 0;
break;
default:
if(ret >= 0)
{
WritePtr += snd_pcm_frames_to_bytes(mPcmHandle, ret);
avail -= ret;
}
break;
}
if(ret < 0)
{
ret = snd_pcm_prepare(mPcmHandle);
if(ret < 0) break;
}
}
}
return 0;
}
void AlsaPlayback::open(std::string_view name)
{
std::string driver{"default"};
if(!name.empty())
{
if(PlaybackDevices.empty())
PlaybackDevices = probe_devices(SND_PCM_STREAM_PLAYBACK);
auto iter = std::find_if(PlaybackDevices.cbegin(), PlaybackDevices.cend(),
[name](const DevMap &entry) -> bool { return entry.name == name; });
if(iter == PlaybackDevices.cend())
throw al::backend_exception{al::backend_error::NoDevice,
"Device name \"%.*s\" not found", static_cast<int>(name.length()), name.data()};
driver = iter->device_name;
}
else
{
name = alsaDevice;
if(auto driveropt = ConfigValueStr(nullptr, "alsa", "device"))
driver = std::move(driveropt).value();
}
TRACE("Opening device \"%s\"\n", driver.c_str());
snd_pcm_t *pcmHandle{};
int err{snd_pcm_open(&pcmHandle, driver.c_str(), SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)};
if(err < 0)
throw al::backend_exception{al::backend_error::NoDevice,
"Could not open ALSA device \"%s\"", driver.c_str()};
if(mPcmHandle)
snd_pcm_close(mPcmHandle);
mPcmHandle = pcmHandle;
/* Free alsa's global config tree. Otherwise valgrind reports a ton of leaks. */
snd_config_update_free_global();
mDevice->DeviceName = name;
}
bool AlsaPlayback::reset()
{
snd_pcm_format_t format{SND_PCM_FORMAT_UNKNOWN};
switch(mDevice->FmtType)
{
case DevFmtByte:
format = SND_PCM_FORMAT_S8;
break;
case DevFmtUByte:
format = SND_PCM_FORMAT_U8;
break;
case DevFmtShort:
format = SND_PCM_FORMAT_S16;
break;
case DevFmtUShort:
format = SND_PCM_FORMAT_U16;
break;
case DevFmtInt:
format = SND_PCM_FORMAT_S32;
break;
case DevFmtUInt:
format = SND_PCM_FORMAT_U32;
break;
case DevFmtFloat:
format = SND_PCM_FORMAT_FLOAT;
break;
}
bool allowmmap{!!GetConfigValueBool(mDevice->DeviceName.c_str(), "alsa", "mmap", true)};
uint periodLen{static_cast<uint>(mDevice->UpdateSize * 1000000_u64 / mDevice->Frequency)};
uint bufferLen{static_cast<uint>(mDevice->BufferSize * 1000000_u64 / mDevice->Frequency)};
uint rate{mDevice->Frequency};
int err{};
HwParamsPtr hp{CreateHwParams()};
#define CHECK(x) do { \
if((err=(x)) < 0) \
throw al::backend_exception{al::backend_error::DeviceError, #x " failed: %s", \
snd_strerror(err)}; \
} while(0)
CHECK(snd_pcm_hw_params_any(mPcmHandle, hp.get()));
/* set interleaved access */
if(!allowmmap
|| snd_pcm_hw_params_set_access(mPcmHandle, hp.get(), SND_PCM_ACCESS_MMAP_INTERLEAVED) < 0)
{
/* No mmap */
CHECK(snd_pcm_hw_params_set_access(mPcmHandle, hp.get(), SND_PCM_ACCESS_RW_INTERLEAVED));
}
/* test and set format (implicitly sets sample bits) */
if(snd_pcm_hw_params_test_format(mPcmHandle, hp.get(), format) < 0)
{
static const struct {
snd_pcm_format_t format;
DevFmtType fmttype;
} formatlist[] = {
{ SND_PCM_FORMAT_FLOAT, DevFmtFloat },
{ SND_PCM_FORMAT_S32, DevFmtInt },
{ SND_PCM_FORMAT_U32, DevFmtUInt },
{ SND_PCM_FORMAT_S16, DevFmtShort },
{ SND_PCM_FORMAT_U16, DevFmtUShort },
{ SND_PCM_FORMAT_S8, DevFmtByte },
{ SND_PCM_FORMAT_U8, DevFmtUByte },
};
for(const auto &fmt : formatlist)
{
format = fmt.format;
if(snd_pcm_hw_params_test_format(mPcmHandle, hp.get(), format) >= 0)
{
mDevice->FmtType = fmt.fmttype;
break;
}
}
}
CHECK(snd_pcm_hw_params_set_format(mPcmHandle, hp.get(), format));
/* set channels (implicitly sets frame bits) */
if(snd_pcm_hw_params_set_channels(mPcmHandle, hp.get(), mDevice->channelsFromFmt()) < 0)
{
uint numchans{2u};
CHECK(snd_pcm_hw_params_set_channels_near(mPcmHandle, hp.get(), &numchans));
if(numchans < 1)
throw al::backend_exception{al::backend_error::DeviceError, "Got 0 device channels"};
if(numchans == 1) mDevice->FmtChans = DevFmtMono;
else mDevice->FmtChans = DevFmtStereo;
}
/* set rate (implicitly constrains period/buffer parameters) */
if(!GetConfigValueBool(mDevice->DeviceName.c_str(), "alsa", "allow-resampler", false)
|| !mDevice->Flags.test(FrequencyRequest))
{
if(snd_pcm_hw_params_set_rate_resample(mPcmHandle, hp.get(), 0) < 0)
WARN("Failed to disable ALSA resampler\n");
}
else if(snd_pcm_hw_params_set_rate_resample(mPcmHandle, hp.get(), 1) < 0)
WARN("Failed to enable ALSA resampler\n");
CHECK(snd_pcm_hw_params_set_rate_near(mPcmHandle, hp.get(), &rate, nullptr));
/* set period time (implicitly constrains period/buffer parameters) */
if((err=snd_pcm_hw_params_set_period_time_near(mPcmHandle, hp.get(), &periodLen, nullptr)) < 0)
ERR("snd_pcm_hw_params_set_period_time_near failed: %s\n", snd_strerror(err));
/* set buffer time (implicitly sets buffer size/bytes/time and period size/bytes) */
if((err=snd_pcm_hw_params_set_buffer_time_near(mPcmHandle, hp.get(), &bufferLen, nullptr)) < 0)
ERR("snd_pcm_hw_params_set_buffer_time_near failed: %s\n", snd_strerror(err));
/* install and prepare hardware configuration */
CHECK(snd_pcm_hw_params(mPcmHandle, hp.get()));
/* retrieve configuration info */
snd_pcm_uframes_t periodSizeInFrames{};
snd_pcm_uframes_t bufferSizeInFrames{};
snd_pcm_access_t access{};
CHECK(snd_pcm_hw_params_get_access(hp.get(), &access));
CHECK(snd_pcm_hw_params_get_period_size(hp.get(), &periodSizeInFrames, nullptr));
CHECK(snd_pcm_hw_params_get_buffer_size(hp.get(), &bufferSizeInFrames));
CHECK(snd_pcm_hw_params_get_channels(hp.get(), &mFrameStep));
hp = nullptr;
SwParamsPtr sp{CreateSwParams()};
CHECK(snd_pcm_sw_params_current(mPcmHandle, sp.get()));
CHECK(snd_pcm_sw_params_set_avail_min(mPcmHandle, sp.get(), periodSizeInFrames));
CHECK(snd_pcm_sw_params_set_stop_threshold(mPcmHandle, sp.get(), bufferSizeInFrames));
CHECK(snd_pcm_sw_params(mPcmHandle, sp.get()));
#undef CHECK
sp = nullptr;
mDevice->BufferSize = static_cast<uint>(bufferSizeInFrames);
mDevice->UpdateSize = static_cast<uint>(periodSizeInFrames);
mDevice->Frequency = rate;
setDefaultChannelOrder();
return true;
}
void AlsaPlayback::start()
{
int err{};
snd_pcm_access_t access{};
HwParamsPtr hp{CreateHwParams()};
#define CHECK(x) do { \
if((err=(x)) < 0) \
throw al::backend_exception{al::backend_error::DeviceError, #x " failed: %s", \
snd_strerror(err)}; \
} while(0)
CHECK(snd_pcm_hw_params_current(mPcmHandle, hp.get()));
/* retrieve configuration info */
CHECK(snd_pcm_hw_params_get_access(hp.get(), &access));
hp = nullptr;
int (AlsaPlayback::*thread_func)(){};
if(access == SND_PCM_ACCESS_RW_INTERLEAVED)
{
auto datalen = snd_pcm_frames_to_bytes(mPcmHandle, mDevice->UpdateSize);
mBuffer.resize(static_cast<size_t>(datalen));
thread_func = &AlsaPlayback::mixerNoMMapProc;
}
else
{
CHECK(snd_pcm_prepare(mPcmHandle));
thread_func = &AlsaPlayback::mixerProc;
}
#undef CHECK
try {
mKillNow.store(false, std::memory_order_release);
mThread = std::thread{std::mem_fn(thread_func), this};
}
catch(std::exception& e) {
throw al::backend_exception{al::backend_error::DeviceError,
"Failed to start mixing thread: %s", e.what()};
}
}
void AlsaPlayback::stop()
{
if(mKillNow.exchange(true, std::memory_order_acq_rel) || !mThread.joinable())
return;
mThread.join();
mBuffer.clear();
int err{snd_pcm_drop(mPcmHandle)};
if(err < 0)
ERR("snd_pcm_drop failed: %s\n", snd_strerror(err));
}
ClockLatency AlsaPlayback::getClockLatency()
{
ClockLatency ret;
std::lock_guard<std::mutex> _{mMutex};
ret.ClockTime = GetDeviceClockTime(mDevice);
snd_pcm_sframes_t delay{};
int err{snd_pcm_delay(mPcmHandle, &delay)};
if(err < 0)
{
ERR("Failed to get pcm delay: %s\n", snd_strerror(err));
delay = 0;
}
ret.Latency = std::chrono::seconds{std::max<snd_pcm_sframes_t>(0, delay)};
ret.Latency /= mDevice->Frequency;
return ret;
}
struct AlsaCapture final : public BackendBase {
AlsaCapture(DeviceBase *device) noexcept : BackendBase{device} { }
~AlsaCapture() override;
void open(std::string_view name) override;
void start() override;
void stop() override;
void captureSamples(std::byte *buffer, uint samples) override;
uint availableSamples() override;
ClockLatency getClockLatency() override;
snd_pcm_t *mPcmHandle{nullptr};
std::vector<std::byte> mBuffer;
bool mDoCapture{false};
RingBufferPtr mRing{nullptr};
snd_pcm_sframes_t mLastAvail{0};
DEF_NEWDEL(AlsaCapture)
};
AlsaCapture::~AlsaCapture()
{
if(mPcmHandle)
snd_pcm_close(mPcmHandle);
mPcmHandle = nullptr;
}
void AlsaCapture::open(std::string_view name)
{
std::string driver{"default"};
if(!name.empty())
{
if(CaptureDevices.empty())
CaptureDevices = probe_devices(SND_PCM_STREAM_CAPTURE);
auto iter = std::find_if(CaptureDevices.cbegin(), CaptureDevices.cend(),
[name](const DevMap &entry) -> bool { return entry.name == name; });
if(iter == CaptureDevices.cend())
throw al::backend_exception{al::backend_error::NoDevice,
"Device name \"%.*s\" not found", static_cast<int>(name.length()), name.data()};
driver = iter->device_name;
}
else
{
name = alsaDevice;
if(auto driveropt = ConfigValueStr(nullptr, "alsa", "capture"))
driver = std::move(driveropt).value();
}
TRACE("Opening device \"%s\"\n", driver.c_str());
int err{snd_pcm_open(&mPcmHandle, driver.c_str(), SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK)};
if(err < 0)
throw al::backend_exception{al::backend_error::NoDevice,
"Could not open ALSA device \"%s\"", driver.c_str()};
/* Free alsa's global config tree. Otherwise valgrind reports a ton of leaks. */
snd_config_update_free_global();
snd_pcm_format_t format{SND_PCM_FORMAT_UNKNOWN};
switch(mDevice->FmtType)
{
case DevFmtByte:
format = SND_PCM_FORMAT_S8;
break;
case DevFmtUByte:
format = SND_PCM_FORMAT_U8;
break;
case DevFmtShort:
format = SND_PCM_FORMAT_S16;
break;
case DevFmtUShort:
format = SND_PCM_FORMAT_U16;
break;
case DevFmtInt:
format = SND_PCM_FORMAT_S32;
break;
case DevFmtUInt:
format = SND_PCM_FORMAT_U32;
break;
case DevFmtFloat:
format = SND_PCM_FORMAT_FLOAT;
break;
}
snd_pcm_uframes_t bufferSizeInFrames{maxu(mDevice->BufferSize, 100*mDevice->Frequency/1000)};
snd_pcm_uframes_t periodSizeInFrames{minu(mDevice->BufferSize, 25*mDevice->Frequency/1000)};
bool needring{false};
HwParamsPtr hp{CreateHwParams()};
#define CHECK(x) do { \
if((err=(x)) < 0) \
throw al::backend_exception{al::backend_error::DeviceError, #x " failed: %s", \
snd_strerror(err)}; \
} while(0)
CHECK(snd_pcm_hw_params_any(mPcmHandle, hp.get()));
/* set interleaved access */
CHECK(snd_pcm_hw_params_set_access(mPcmHandle, hp.get(), SND_PCM_ACCESS_RW_INTERLEAVED));
/* set format (implicitly sets sample bits) */
CHECK(snd_pcm_hw_params_set_format(mPcmHandle, hp.get(), format));
/* set channels (implicitly sets frame bits) */
CHECK(snd_pcm_hw_params_set_channels(mPcmHandle, hp.get(), mDevice->channelsFromFmt()));
/* set rate (implicitly constrains period/buffer parameters) */
CHECK(snd_pcm_hw_params_set_rate(mPcmHandle, hp.get(), mDevice->Frequency, 0));
/* set buffer size in frame units (implicitly sets period size/bytes/time and buffer time/bytes) */
if(snd_pcm_hw_params_set_buffer_size_min(mPcmHandle, hp.get(), &bufferSizeInFrames) < 0)
{
TRACE("Buffer too large, using intermediate ring buffer\n");
needring = true;
CHECK(snd_pcm_hw_params_set_buffer_size_near(mPcmHandle, hp.get(), &bufferSizeInFrames));
}
/* set buffer size in frame units (implicitly sets period size/bytes/time and buffer time/bytes) */
CHECK(snd_pcm_hw_params_set_period_size_near(mPcmHandle, hp.get(), &periodSizeInFrames, nullptr));
/* install and prepare hardware configuration */
CHECK(snd_pcm_hw_params(mPcmHandle, hp.get()));
/* retrieve configuration info */
CHECK(snd_pcm_hw_params_get_period_size(hp.get(), &periodSizeInFrames, nullptr));
#undef CHECK
hp = nullptr;
if(needring)
mRing = RingBuffer::Create(mDevice->BufferSize, mDevice->frameSizeFromFmt(), false);
mDevice->DeviceName = name;
}
void AlsaCapture::start()
{
int err{snd_pcm_prepare(mPcmHandle)};
if(err < 0)
throw al::backend_exception{al::backend_error::DeviceError, "snd_pcm_prepare failed: %s",
snd_strerror(err)};
err = snd_pcm_start(mPcmHandle);
if(err < 0)
throw al::backend_exception{al::backend_error::DeviceError, "snd_pcm_start failed: %s",
snd_strerror(err)};
mDoCapture = true;
}
void AlsaCapture::stop()
{
/* OpenAL requires access to unread audio after stopping, but ALSA's
* snd_pcm_drain is unreliable and snd_pcm_drop drops it. Capture what's
* available now so it'll be available later after the drop.
*/
uint avail{availableSamples()};
if(!mRing && avail > 0)
{
/* The ring buffer implicitly captures when checking availability.
* Direct access needs to explicitly capture it into temp storage.
*/
auto temp = std::vector<std::byte>(
static_cast<size_t>(snd_pcm_frames_to_bytes(mPcmHandle, avail)));
captureSamples(temp.data(), avail);
mBuffer = std::move(temp);
}
int err{snd_pcm_drop(mPcmHandle)};
if(err < 0)
ERR("drop failed: %s\n", snd_strerror(err));
mDoCapture = false;
}
void AlsaCapture::captureSamples(std::byte *buffer, uint samples)
{
if(mRing)
{
mRing->read(buffer, samples);
return;
}
mLastAvail -= samples;
while(mDevice->Connected.load(std::memory_order_acquire) && samples > 0)
{
snd_pcm_sframes_t amt{0};
if(!mBuffer.empty())
{
/* First get any data stored from the last stop */
amt = snd_pcm_bytes_to_frames(mPcmHandle, static_cast<ssize_t>(mBuffer.size()));
if(static_cast<snd_pcm_uframes_t>(amt) > samples) amt = samples;
amt = snd_pcm_frames_to_bytes(mPcmHandle, amt);
std::copy_n(mBuffer.begin(), amt, buffer);
mBuffer.erase(mBuffer.begin(), mBuffer.begin()+amt);
amt = snd_pcm_bytes_to_frames(mPcmHandle, amt);
}
else if(mDoCapture)
amt = snd_pcm_readi(mPcmHandle, buffer, samples);
if(amt < 0)
{
ERR("read error: %s\n", snd_strerror(static_cast<int>(amt)));
if(amt == -EAGAIN)
continue;
if((amt=snd_pcm_recover(mPcmHandle, static_cast<int>(amt), 1)) >= 0)
{
amt = snd_pcm_start(mPcmHandle);
if(amt >= 0)
amt = snd_pcm_avail_update(mPcmHandle);
}
if(amt < 0)
{
const char *err{snd_strerror(static_cast<int>(amt))};
ERR("restore error: %s\n", err);
mDevice->handleDisconnect("Capture recovery failure: %s", err);
break;
}
/* If the amount available is less than what's asked, we lost it
* during recovery. So just give silence instead. */
if(static_cast<snd_pcm_uframes_t>(amt) < samples)
break;
continue;
}
buffer = buffer + amt;
samples -= static_cast<uint>(amt);
}
if(samples > 0)
std::fill_n(buffer, snd_pcm_frames_to_bytes(mPcmHandle, samples),
std::byte((mDevice->FmtType == DevFmtUByte) ? 0x80 : 0));
}
uint AlsaCapture::availableSamples()
{
snd_pcm_sframes_t avail{0};
if(mDevice->Connected.load(std::memory_order_acquire) && mDoCapture)
avail = snd_pcm_avail_update(mPcmHandle);
if(avail < 0)
{
ERR("avail update failed: %s\n", snd_strerror(static_cast<int>(avail)));
if((avail=snd_pcm_recover(mPcmHandle, static_cast<int>(avail), 1)) >= 0)
{
if(mDoCapture)
avail = snd_pcm_start(mPcmHandle);
if(avail >= 0)
avail = snd_pcm_avail_update(mPcmHandle);
}
if(avail < 0)
{
const char *err{snd_strerror(static_cast<int>(avail))};
ERR("restore error: %s\n", err);
mDevice->handleDisconnect("Capture recovery failure: %s", err);
}
}
if(!mRing)
{
if(avail < 0) avail = 0;
avail += snd_pcm_bytes_to_frames(mPcmHandle, static_cast<ssize_t>(mBuffer.size()));
if(avail > mLastAvail) mLastAvail = avail;
return static_cast<uint>(mLastAvail);
}
while(avail > 0)
{
auto vec = mRing->getWriteVector();
if(vec.first.len == 0) break;
snd_pcm_sframes_t amt{std::min(static_cast<snd_pcm_sframes_t>(vec.first.len), avail)};
amt = snd_pcm_readi(mPcmHandle, vec.first.buf, static_cast<snd_pcm_uframes_t>(amt));
if(amt < 0)
{
ERR("read error: %s\n", snd_strerror(static_cast<int>(amt)));
if(amt == -EAGAIN)
continue;
if((amt=snd_pcm_recover(mPcmHandle, static_cast<int>(amt), 1)) >= 0)
{
if(mDoCapture)
amt = snd_pcm_start(mPcmHandle);
if(amt >= 0)
amt = snd_pcm_avail_update(mPcmHandle);
}
if(amt < 0)
{
const char *err{snd_strerror(static_cast<int>(amt))};
ERR("restore error: %s\n", err);
mDevice->handleDisconnect("Capture recovery failure: %s", err);
break;
}
avail = amt;
continue;
}
mRing->writeAdvance(static_cast<snd_pcm_uframes_t>(amt));
avail -= amt;
}
return static_cast<uint>(mRing->readSpace());
}
ClockLatency AlsaCapture::getClockLatency()
{
ClockLatency ret;
ret.ClockTime = GetDeviceClockTime(mDevice);
snd_pcm_sframes_t delay{};
int err{snd_pcm_delay(mPcmHandle, &delay)};
if(err < 0)
{
ERR("Failed to get pcm delay: %s\n", snd_strerror(err));
delay = 0;
}
ret.Latency = std::chrono::seconds{std::max<snd_pcm_sframes_t>(0, delay)};
ret.Latency /= mDevice->Frequency;
return ret;
}
} // namespace
bool AlsaBackendFactory::init()
{
bool error{false};
#ifdef HAVE_DYNLOAD
if(!alsa_handle)
{
std::string missing_funcs;
alsa_handle = LoadLib("libasound.so.2");
if(!alsa_handle)
{
WARN("Failed to load %s\n", "libasound.so.2");
return false;
}
error = false;
#define LOAD_FUNC(f) do { \
p##f = al::bit_cast<decltype(p##f)>(GetSymbol(alsa_handle, #f)); \
if(p##f == nullptr) { \
error = true; \
missing_funcs += "\n" #f; \
} \
} while(0)
ALSA_FUNCS(LOAD_FUNC);
#undef LOAD_FUNC
if(error)
{
WARN("Missing expected functions:%s\n", missing_funcs.c_str());
CloseLib(alsa_handle);
alsa_handle = nullptr;
}
}
#endif
return !error;
}
bool AlsaBackendFactory::querySupport(BackendType type)
{ return (type == BackendType::Playback || type == BackendType::Capture); }
std::string AlsaBackendFactory::probe(BackendType type)
{
std::string outnames;
auto add_device = [&outnames](const DevMap &entry) -> void
{
/* +1 to also append the null char (to ensure a null-separated list and
* double-null terminated list).
*/
outnames.append(entry.name.c_str(), entry.name.length()+1);
};
switch(type)
{
case BackendType::Playback:
PlaybackDevices = probe_devices(SND_PCM_STREAM_PLAYBACK);
std::for_each(PlaybackDevices.cbegin(), PlaybackDevices.cend(), add_device);
break;
case BackendType::Capture:
CaptureDevices = probe_devices(SND_PCM_STREAM_CAPTURE);
std::for_each(CaptureDevices.cbegin(), CaptureDevices.cend(), add_device);
break;
}
return outnames;
}
BackendPtr AlsaBackendFactory::createBackend(DeviceBase *device, BackendType type)
{
if(type == BackendType::Playback)
return BackendPtr{new AlsaPlayback{device}};
if(type == BackendType::Capture)
return BackendPtr{new AlsaCapture{device}};
return nullptr;
}
BackendFactory &AlsaBackendFactory::getFactory()
{
static AlsaBackendFactory factory{};
return factory;
}
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