audioengine.h

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/*
 * Copyright (C) 2006-2011 David Robillard <d@drobilla.net>
 * Copyright (C) 2006-2019 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2007-2012 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2012-2019 Robin Gareus <robin@gareus.org>
 * Copyright (C) 2013-2015 Tim Mayberry <mojofunk@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#pragma once
 
#ifdef WAF_BUILD
#include "libardour-config.h"
#endif
 
#include <atomic>
#include <iostream>
#include <list>
#include <set>
#include <cmath>
#include <exception>
#include <string>
 
#include "pbd/mutex.h"
#include "pbd/signals.h"
#include "pbd/pthread_utils.h"
 
#include "ardour/ardour.h"
#include "ardour/data_type.h"
#include "ardour/session_handle.h"
#include "ardour/libardour_visibility.h"
#include "ardour/types.h"
#include "ardour/chan_count.h"
#include "ardour/port_manager.h"
 
class MTDM;
 
namespace ARDOUR {
 
class InternalPort;
class MidiPort;
class MIDIDM;
class Port;
class Session;
class ProcessThread;
class AudioBackend;
struct AudioBackendInfo;
 
class LIBARDOUR_API AudioEngine : public PortManager, public SessionHandlePtr
{
  public:
 
        static AudioEngine* create ();
 
        virtual ~AudioEngine ();
 
        int discover_backends();
        std::vector<const AudioBackendInfo*> available_backends() const;
        std::string current_backend_name () const;
        std::shared_ptr<AudioBackend> set_backend (const std::string&, const std::string& arg1, const std::string& arg2);
        std::shared_ptr<AudioBackend> current_backend() const { return _backend; }
        bool setup_required () const;
        bool is_jack () const;
 
        ProcessThread* main_thread() const { return _main_thread; }
 
        /* START BACKEND PROXY API
         *
         * See audio_backend.h for full documentation and semantics. These wrappers
         * just forward to a backend implementation.
         */
 
        int            start (bool for_latency_measurement=false);
        int            stop (bool for_latency_measurement=false);
        int            freewheel (bool start_stop);
        float          get_dsp_load() const ;
        void           transport_start ();
        void           transport_stop ();
        TransportState transport_state ();
        void           transport_locate (samplepos_t pos);
        samplepos_t     transport_sample();
        samplecnt_t     sample_rate () const;
        pframes_t      samples_per_cycle () const;
        int            usecs_per_cycle () const;
        size_t         raw_buffer_size (DataType t);
        samplepos_t     sample_time ();
        samplepos_t     sample_time_at_cycle_start ();
        pframes_t      samples_since_cycle_start ();
        bool           get_sync_offset (pframes_t& offset) const;
 
        std::string    get_last_backend_error () const { return _last_backend_error_string; }
 
        int            create_process_thread (std::function<void()> func);
        int            join_process_threads ();
        bool           in_process_thread ();
        uint32_t       process_thread_count ();
 
        int            backend_reset_requested();
        void           request_backend_reset();
        void           request_device_list_update();
        void           launch_device_control_app();
 
        // for the user which hold state_lock to check if reset operation is pending
        bool           is_reset_requested() const { return _hw_reset_request_count.load(); }
 
        int set_device_name (const std::string&);
        int set_sample_rate (float);
        int set_buffer_size (uint32_t);
        int set_interleaved (bool yn);
        int set_systemic_input_latency (uint32_t);
        int set_systemic_output_latency (uint32_t);
 
        /* END BACKEND PROXY API */
 
        bool freewheeling() const { return _freewheeling; }
        bool running() const { return _running; }
 
        std::string backend_id (bool for_input);
 
        PBD::Mutex& process_lock() { return _process_lock; }
        PBD::Mutex& latency_lock() { return _latency_lock; }
 
        int request_buffer_size (pframes_t samples) {
                return set_buffer_size (samples);
        }
 
        samplecnt_t processed_samples() const { return _processed_samples; }
 
        void set_session (Session *);
        void remove_session (); // not a replacement for SessionHandle::session_going_away()
        Session* session() const { return _session; }
 
        class NoBackendAvailable : public std::exception {
            public:
                virtual const char *what() const throw() { return "could not connect to engine backend"; }
        };
 
        void split_cycle (pframes_t offset);
 
        int  reset_timebase ();
 
        void update_latencies ();
 
        /* this signal is sent for every process() cycle while freewheeling.
           (the regular process() call to session->process() is not made)
        */
 
        PBD::Signal<void(pframes_t)> Freewheel;
 
        PBD::Signal<void()> Xrun;
 
        PBD::Signal<void(samplecnt_t)> SampleRateChanged;
 
        PBD::Signal<void(pframes_t)> BufferSizeChanged;
 
        PBD::Signal<void()> DeviceError;
 
        /* this signal is emitted if the device list changed */
 
        PBD::Signal<void()> DeviceListChanged;
 
        /* this signal is sent if the backend ever disconnects us */
 
        PBD::Signal<void(const char*)> Halted;
 
        /* these two are emitted when the engine itself is
           started and stopped
        */
 
        PBD::Signal<void(uint32_t)> Running;
        PBD::Signal<void()> Stopped;
 
        /* these two are emitted when a device reset is initiated/finished
         */
 
        PBD::Signal<void()> DeviceResetStarted;
        PBD::Signal<void()> DeviceResetFinished;
 
        static AudioEngine* instance() { return _instance; }
        static void destroy();
 
        void died ();
 
        /* The backend will cause these at the appropriate time(s) */
        int  process_callback (pframes_t nframes);
        int  buffer_size_change (pframes_t nframes);
        int  sample_rate_change (pframes_t nframes);
        void freewheel_callback (bool);
        void timebase_callback (TransportState state, pframes_t nframes, samplepos_t pos, int new_position);
        int  sync_callback (TransportState state, samplepos_t position);
        int  port_registration_callback ();
        void latency_callback (bool for_playback);
        void halted_callback (const char* reason);
 
        /* checks if current thread is properly set up for audio processing */
        static bool thread_initialised_for_audio_processing ();
 
        /* sets up the process callback thread */
        static void thread_init_callback (void *);
 
        /* latency measurement */
 
        MTDM* mtdm() { return _mtdm; }
        MIDIDM* mididm() { return _mididm; }
 
        int  prepare_for_latency_measurement ();
        int  start_latency_detection (bool);
        void stop_latency_detection ();
        void set_latency_input_port (const std::string&);
        void set_latency_output_port (const std::string&);
        uint32_t latency_signal_delay () const { return _latency_signal_latency; }
 
        enum LatencyMeasurement {
                MeasureNone,
                MeasureAudio,
                MeasureMIDI
        };
 
        LatencyMeasurement measuring_latency () const { return _measuring_latency; }
 
        /* These two are used only in builds where SILENCE_AFTER_SECONDS was
         * set. BecameSilent will be emitted when the audioengine goes silent.
         * reset_silence_countdown() can be used to reset the silence
         * countdown, whose duration will be reduced to half of its previous
         * value.
         */
 
        PBD::Signal<void()> BecameSilent;
        void reset_silence_countdown ();
 
        void add_pending_port_deletion (Port*);
        void queue_latency_update (bool);
 
        enum TimingTypes {
                ProcessCallback = 0,
                /* end */
                NTT = 1
        };
 
        PBD::TimingStats dsp_stats[NTT];
 
  private:
        AudioEngine ();
 
        static AudioEngine*       _instance;
 
        PBD::Mutex                _process_lock;
        PBD::Mutex                _latency_lock;
        PBD::Cond                 _session_removed;
        std::recursive_mutex      _state_lock;
        bool                       session_remove_pending;
        sampleoffset_t             session_removal_countdown;
        bool                       session_deleted;
        gain_t                     session_removal_gain;
        gain_t                     session_removal_gain_step;
        bool                      _running;
        bool                      _freewheeling;
        samplecnt_t                monitor_check_interval;
        samplecnt_t                last_monitor_check;
        samplecnt_t               _processed_samples;
        ProcessThread*            _main_thread;
        MTDM*                     _mtdm;
        MIDIDM*                   _mididm;
        LatencyMeasurement        _measuring_latency;
        PortEngine::PortPtr       _latency_input_port;
        PortEngine::PortPtr       _latency_output_port;
        samplecnt_t               _latency_flush_samples;
        std::string               _latency_input_name;
        std::string               _latency_output_name;
        samplecnt_t               _latency_signal_latency;
        bool                      _stopped_for_latency;
        bool                      _started_for_latency;
        bool                      _in_destructor;
 
        std::string               _last_backend_error_string;
        PBD::Thread*              _hw_reset_event_thread;
        std::atomic<int>          _hw_reset_request_count;
        PBD::Cond                 _hw_reset_condition;
        PBD::Mutex                _reset_request_lock;
        std::atomic<int>          _stop_hw_reset_processing;
        PBD::Thread*              _hw_devicelist_update_thread;
        std::atomic<int>          _hw_devicelist_update_count;
        PBD::Cond                 _hw_devicelist_update_condition;
        PBD::Mutex                _devicelist_update_lock;
        std::atomic<int>          _stop_hw_devicelist_processing;
        uint32_t                  _start_cnt;
        uint32_t                  _init_countdown;
        std::atomic<int>          _pending_playback_latency_callback;
        std::atomic<int>          _pending_capture_latency_callback;
 
        void start_hw_event_processing();
        void stop_hw_event_processing();
        void do_reset_backend();
        void do_devicelist_update();
 
        typedef std::map<std::string,AudioBackendInfo*> BackendMap;
        BackendMap _backends;
        AudioBackendInfo* backend_discover (const std::string&);
        void drop_backend ();
 
#ifdef SILENCE_AFTER
        samplecnt_t _silence_countdown;
        uint32_t   _silence_hit_cnt;
#endif
 
};
 
} // namespace ARDOUR