jack_policy.h

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/******************************************************************************
 Copyright (c) 2012-2016 Institut für Nachrichtentechnik, Universität Rostock
 Copyright (c) 2006-2012 Quality & Usability Lab
                         Deutsche Telekom Laboratories, TU Berlin
 
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// https://AudioProcessingFramework.github.io/
 
 
#ifndef APF_JACK_POLICY_H
#define APF_JACK_POLICY_H
 
#ifdef APF_JACK_POLICY_DEBUG
#include <cstdio>  // for printf()
#endif
 
#include <cassert>  // for assert()
 
#include "apf/jackclient.h"
#include "apf/parameter_map.h"
#include "apf/stringtools.h"
#include "apf/iterator.h"  // for has_begin_and_end
 
#ifndef APF_MIMOPROCESSOR_INTERFACE_POLICY
#define APF_MIMOPROCESSOR_INTERFACE_POLICY apf::jack_policy
#endif
 
namespace apf
{
 
class jack_policy : public JackClient
{
  public:
    using sample_type = sample_t;
    class Input;
    class Output;
 
    using JackClient::activate;
    using JackClient::deactivate;
    using JackClient::sample_rate;
 
    nframes_t block_size() const { return this->buffer_size(); }
 
  protected:
    explicit jack_policy(const parameter_map& p = parameter_map())
      : JackClient(p.get("name", "MimoProcessor"), use_jack_process_callback)
    {}
 
    virtual ~jack_policy() = default;
 
  private:
    template<typename X> class Xput;
 
    struct i_am_in
    {
      using iterator = const sample_type*;
      static const bool is_input = true;
      static std::string prefix_name() { return "input_prefix"; }
      static std::string default_prefix() { return "in_"; }
    };
 
    struct i_am_out
    {
      using iterator = sample_type*;
      static const bool is_input = false;
      static std::string prefix_name() { return "output_prefix"; }
      static std::string default_prefix() { return "out_"; }
    };
 
    virtual int jack_process_callback(nframes_t nframes)
    {
      (void)nframes;
      assert(nframes == this->block_size());
      try
      {
        // call virtual member function which is implemented in derived class
        // (template method design pattern)
        this->process();
      }
      catch (std::exception& e)
      {
#ifdef APF_JACK_POLICY_DEBUG
        printf("Error in process callback: %s\n", e.what());
#endif
        return 1;  // Stop calling the callback
      }
      return 0;
    }
 
    virtual void process() = 0;
};
 
template<typename interface_policy, typename native_handle_type>
struct thread_traits;  // definition in mimoprocessor.h
 
template<>
struct thread_traits<jack_policy, pthread_t>
{
  static void update_priority(const jack_policy& obj, pthread_t thread_id) noexcept
  {
    if (obj.is_realtime())
    {
#ifdef APF_JACK_POLICY_DEBUG
    printf("Trying to set priority...");
#endif
      struct sched_param param;
      param.sched_priority = obj.get_real_time_priority();
      if (pthread_setschedparam(thread_id, SCHED_FIFO, &param))
      {
        // We were trying our best to set the priority, but if it doesn't work,
        // the show must go on!
#ifdef APF_JACK_POLICY_DEBUG
        printf("Can't set scheduling priority %d for thread!\n", param.sched_priority);
#endif
      }
    }
    else
    {
      // do nothing
    }
#ifdef APF_JACK_POLICY_DEBUG
    struct sched_param param;
    int policy;
    pthread_getschedparam(thread_id, &policy, &param);
    printf("worker thread: policy=%s, priority=%d\n",
        (policy == SCHED_FIFO)  ? "SCHED_FIFO" :
        (policy == SCHED_RR)    ? "SCHED_RR" :
        (policy == SCHED_OTHER) ? "SCHED_OTHER" :
        "???",
        param.sched_priority);
#endif
  }
};
 
// Helper class to avoid code duplication in Input and Output
template<typename X>
class jack_policy::Xput
{
  public:
    using iterator = typename X::iterator;
 
    struct buffer_type : has_begin_and_end<iterator> { friend class Xput; };
 
    void fetch_buffer()
    {
      this->buffer._begin = static_cast<sample_type*>(
          jack_port_get_buffer(_port, _parent.block_size()));
      this->buffer._end   = this->buffer._begin + _parent.block_size();
    }
 
    std::string port_name() const { return _port_name; }
 
    buffer_type buffer;
 
  protected:
     Xput(jack_policy& parent, const parameter_map& p);
 
    ~Xput() { _parent.unregister_port(_port); }
 
  private:
    Xput(const Xput&); Xput& operator=(const Xput&);  // deactivated
 
    jack_policy& _parent;
    JackClient::port_t* _port;  // JACK port corresponding to this object.
 
    JackClient::port_t* _init_port(const parameter_map& p, jack_policy& parent);
 
    const std::string _port_name;  // actual JACK port name
};
 
template<typename X>
JackClient::port_t*
jack_policy::Xput<X>::_init_port(const parameter_map& p, jack_policy& parent)
{
  auto name = std::string();
 
  // first, try port_name
  if (p.has_key("port_name"))
  {
    name = p["port_name"];
  }
  else
  {
    // then concatenate "input_prefix"/"output_prefix" with "id"
    // if the prefix isn't specified, it's replaced by a default string
    // worst case: duplicate string -> port registration will fail!
 
    auto id = std::string();
 
    if (p.has_key("id"))
    {
      id = p.get("id", "");
    }
    else
    {
      static int next_id = 1;
      id = str::A2S(next_id++);
    }
 
    name = p.get(X::prefix_name(), X::default_prefix()) + id;
  }
  JackClient::port_t* rport = X::is_input ? parent.register_in_port(name) : parent.register_out_port(name);
  if (rport==NULL){
    throw std::runtime_error("Could not register JACK port!");
  }
  return rport;
}
 
template<typename X>
jack_policy::Xput<X>::Xput(jack_policy& parent, const parameter_map& p)
  : _parent(parent)
  , _port(_init_port(p, _parent))
  // get actual port name and save it to member variable
  , _port_name(_port ? jack_port_name(_port) : "")
{
  // optionally connect to jack_port
  std::string connect_to = p.get("connect-to", "");
  if (connect_to != "")
  {
    if (X::is_input)
    {
      _parent.connect_ports(connect_to, _port_name);
    }
    else
    {
      _parent.connect_ports(_port_name, connect_to);
    }
  }
}
 
class jack_policy::Input : public Xput<i_am_in>
{
  protected:
    Input(jack_policy& parent, const parameter_map& p)
      : Xput<i_am_in>(parent, p)
    {}
 
    ~Input() = default;
};
 
class jack_policy::Output : public Xput<i_am_out>
{
  protected:
    Output(jack_policy& parent, const parameter_map& p)
      : Xput<i_am_out>(parent, p)
    {}
 
    ~Output() = default;
};
 
}  // namespace apf
 
#endif