basic_block.h

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/* -*- c++ -*- */
/*
 * Copyright 2006,2008,2009,2011,2013 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio 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 3, or (at your option)
 * any later version.
 *
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef INCLUDED_GR_BASIC_BLOCK_H
#define INCLUDED_GR_BASIC_BLOCK_H

#include <gnuradio/api.h>
#include <gnuradio/sptr_magic.h>
#include <gnuradio/msg_accepter.h>
#include <gnuradio/runtime_types.h>
#include <gnuradio/io_signature.h>
#include <gnuradio/thread/thread.h>
#include <boost/enable_shared_from_this.hpp>
#include <boost/function.hpp>
#include <boost/foreach.hpp>
#include <boost/thread/condition_variable.hpp>
#include <iostream>
#include <string>
#include <deque>
#include <map>

#ifdef GR_CTRLPORT
#include <gnuradio/rpcregisterhelpers.h>
#endif

namespace gr {

  /*!
   * \brief The abstract base class for all signal processing blocks.
   * \ingroup internal
   *
   * Basic blocks are the bare abstraction of an entity that has a
   * name, a set of inputs and outputs, and a message queue.  These
   * are never instantiated directly; rather, this is the abstract
   * parent class of both gr_hier_block, which is a recursive
   * container, and block, which implements actual signal
   * processing functions.
   */
  class GR_RUNTIME_API basic_block : public msg_accepter,
                                     public boost::enable_shared_from_this<basic_block>
  {
    typedef boost::function<void(pmt::pmt_t)> msg_handler_t;

  private:
    typedef std::map<pmt::pmt_t , msg_handler_t, pmt::comparator> d_msg_handlers_t;
    d_msg_handlers_t d_msg_handlers;

    typedef std::deque<pmt::pmt_t> msg_queue_t;
    typedef std::map<pmt::pmt_t, msg_queue_t, pmt::comparator> msg_queue_map_t;
    typedef std::map<pmt::pmt_t, msg_queue_t, pmt::comparator>::iterator msg_queue_map_itr;
    std::map<pmt::pmt_t, boost::shared_ptr<boost::condition_variable>, pmt::comparator> msg_queue_ready;

    gr::thread::mutex mutex;          //< protects all vars

  protected:
    friend class flowgraph;
    friend class flat_flowgraph; // TODO: will be redundant
    friend class tpb_thread_body;

    enum vcolor { WHITE, GREY, BLACK };

    std::string       d_name;
    gr::io_signature::sptr d_input_signature;
    gr::io_signature::sptr d_output_signature;
    long              d_unique_id;
    long              d_symbolic_id;
    std::string       d_symbol_name;
    std::string       d_symbol_alias;
    vcolor            d_color;
    bool              d_rpc_set;

    msg_queue_map_t msg_queue;
    std::vector<boost::any> d_rpc_vars; // container for all RPC variables

    basic_block(void) {} // allows pure virtual interface sub-classes

    //! Protected constructor prevents instantiation by non-derived classes
    basic_block(const std::string &name,
                gr::io_signature::sptr input_signature,
                gr::io_signature::sptr output_signature);

    //! may only be called during constructor
    void set_input_signature(gr::io_signature::sptr iosig) {
      d_input_signature = iosig;
    }

    //! may only be called during constructor
    void set_output_signature(gr::io_signature::sptr iosig) {
      d_output_signature = iosig;
    }

    /*!
     * \brief Allow the flowgraph to set for sorting and partitioning
     */
    void set_color(vcolor color) { d_color = color; }
    vcolor color() const { return d_color; }

    /*!
     * \brief Tests if there is a handler attached to port \p which_port
     */
    virtual bool has_msg_handler(pmt::pmt_t which_port) {
      return (d_msg_handlers.find(which_port) != d_msg_handlers.end());
    }

    /*
     * This function is called by the runtime system to dispatch messages.
     *
     * The thread-safety guarantees mentioned in set_msg_handler are
     * implemented by the callers of this method.
     */
    virtual void dispatch_msg(pmt::pmt_t which_port, pmt::pmt_t msg)
    {
      // AA Update this
      if(has_msg_handler(which_port)) {  // Is there a handler?
        d_msg_handlers[which_port](msg); // Yes, invoke it.
      }
    }

    // Message passing interface
    pmt::pmt_t d_message_subscribers;

  public:
    pmt::pmt_t message_subscribers(pmt::pmt_t port);
    virtual ~basic_block();
    long unique_id() const { return d_unique_id; }
    long symbolic_id() const { return d_symbolic_id; }

    /*! The name of the block */
    std::string name() const { return d_name; }

    /*!
     * The sybolic name of the block, which is used in the
     * block_registry. The name is assigned by the block's constructor
     * and never changes during the life of the block.
     */
    std::string symbol_name() const { return d_symbol_name; }

    gr::io_signature::sptr input_signature() const  { return d_input_signature; }
    gr::io_signature::sptr output_signature() const { return d_output_signature; }
    basic_block_sptr to_basic_block(); // Needed for Python type coercion

    /*!
     * True if the block has an alias (see set_block_alias).
     */
    bool alias_set() { return !d_symbol_alias.empty(); }

    /*!
     * Returns the block's alias as a string.
     */
    std::string alias(){ return alias_set()?d_symbol_alias:symbol_name(); }

    /*!
     * Returns the block's alias as PMT.
     */
    pmt::pmt_t alias_pmt(){ return pmt::intern(alias()); }

    /*!
     * Set's a new alias for the block; also adds an entry into the
     * block_registry to get the block using either the alias or the
     * original symbol name.
     */
    void set_block_alias(std::string name);

    // ** Message passing interface **
    void message_port_register_in(pmt::pmt_t port_id);
    void message_port_register_out(pmt::pmt_t port_id);
    void message_port_pub(pmt::pmt_t port_id, pmt::pmt_t msg);
    void message_port_sub(pmt::pmt_t port_id, pmt::pmt_t target);
    void message_port_unsub(pmt::pmt_t port_id, pmt::pmt_t target);

    virtual bool message_port_is_hier(pmt::pmt_t port_id) { (void) port_id; return false; }
    virtual bool message_port_is_hier_in(pmt::pmt_t port_id) { (void) port_id; return false; }
    virtual bool message_port_is_hier_out(pmt::pmt_t port_id) { (void) port_id; return false; }

    /*!
     * \brief Get input message port names.
     *
     * Returns the available input message ports for a block. The
     * return object is a PMT vector that is filled with PMT symbols.
     */
    pmt::pmt_t message_ports_in();

    /*!
     * \brief Get output message port names.
     *
     * Returns the available output message ports for a block. The
     * return object is a PMT vector that is filled with PMT symbols.
     */
    pmt::pmt_t message_ports_out();

    /*!
     * Accept msg, place in queue, arrange for thread to be awakened if it's not already.
     */
    void _post(pmt::pmt_t which_port, pmt::pmt_t msg);

    //! is the queue empty?
    bool empty_p(pmt::pmt_t which_port) {
      if(msg_queue.find(which_port) == msg_queue.end())
        throw std::runtime_error("port does not exist!");
      return msg_queue[which_port].empty();
    }
    bool empty_p() {
      bool rv = true;
      BOOST_FOREACH(msg_queue_map_t::value_type &i, msg_queue) {
        rv &= msg_queue[i.first].empty();
      }
      return rv;
    }

    //! are all msg ports with handlers empty?
    bool empty_handled_p(pmt::pmt_t which_port){
        return (empty_p(which_port) || !has_msg_handler(which_port));
    }
    bool empty_handled_p() {
      bool rv = true;
      BOOST_FOREACH(msg_queue_map_t::value_type &i, msg_queue) {
        rv &= empty_handled_p(i.first);
      }
      return rv;
    }

    //! How many messages in the queue?
    size_t nmsgs(pmt::pmt_t which_port) {
      if(msg_queue.find(which_port) == msg_queue.end())
        throw std::runtime_error("port does not exist!");
      return msg_queue[which_port].size();
    }

    //| Acquires and release the mutex
    void insert_tail( pmt::pmt_t which_port, pmt::pmt_t msg);
    /*!
     * \returns returns pmt at head of queue or pmt::pmt_t() if empty.
     */
    pmt::pmt_t delete_head_nowait( pmt::pmt_t which_port);

    /*!
     * \param[in] which_port The message port from which to get the message.
     * \param[in] millisec Optional timeout value (0=no timeout).
     * \returns returns pmt at head of queue or pmt::pmt_t() if empty.
     */
    pmt::pmt_t delete_head_blocking(pmt::pmt_t which_port, unsigned int millisec = 0);

    msg_queue_t::iterator get_iterator(pmt::pmt_t which_port) {
      return msg_queue[which_port].begin();
    }

    void erase_msg(pmt::pmt_t which_port, msg_queue_t::iterator it) {
      msg_queue[which_port].erase(it);
    }

    virtual bool has_msg_port(pmt::pmt_t which_port) {
      if(msg_queue.find(which_port) != msg_queue.end()) {
        return true;
      }
      if(pmt::dict_has_key(d_message_subscribers, which_port)) {
        return true;
      }
      return false;
    }

    const msg_queue_map_t& get_msg_map(void) const {
      return msg_queue;
    }

#ifdef GR_CTRLPORT
    /*!
     * \brief Add an RPC variable (get or set).
     *
     * Using controlport, we create new getters/setters and need to
     * store them. Each block has a vector to do this, and these never
     * need to be accessed again once they are registered with the RPC
     * backend. This function takes a
     * boost::shared_sptr<rpcbasic_base> so that when the block is
     * deleted, all RPC registered variables are cleaned up.
     *
     * \param s an rpcbasic_sptr of the new RPC variable register to store.
     */
    void add_rpc_variable(rpcbasic_sptr s)
    {
      d_rpc_vars.push_back(s);
    }
#endif /* GR_CTRLPORT */

    /*!
     * \brief Set up the RPC registered variables.
     *
     * This must be overloaded by a block that wants to use
     * controlport. This is where rpcbasic_register_{get,set} pointers
     * are created, which then get wrapped as shared pointers
     * (rpcbasic_sptr(...)) and stored using add_rpc_variable.
     */
    virtual void setup_rpc() {};

    /*!
     * \brief Ask if this block has been registered to the RPC.
     *
     * We can only register a block once, so we use this to protect us
     * from calling it multiple times.
     */
    bool is_rpc_set() { return d_rpc_set; }

    /*!
     * \brief When the block is registered with the RPC, set this.
     */
    void rpc_set() { d_rpc_set = true; }

    /*!
     * \brief Confirm that ninputs and noutputs is an acceptable combination.
     *
     * \param ninputs   number of input streams connected
     * \param noutputs  number of output streams connected
     *
     * \returns true if this is a valid configuration for this block.
     *
     * This function is called by the runtime system whenever the
     * topology changes. Most classes do not need to override this.
     * This check is in addition to the constraints specified by the
     * input and output gr::io_signatures.
     */
    virtual bool check_topology(int ninputs, int noutputs) {
      (void)ninputs;
      (void)noutputs;
      return true;
    }

    /*!
     * \brief Set the callback that is fired when messages are available.
     *
     * \p msg_handler can be any kind of function pointer or function object
     * that has the signature:
     * <pre>
     *    void msg_handler(pmt::pmt msg);
     * </pre>
     *
     * (You may want to use boost::bind to massage your callable into
     * the correct form.  See gr::blocks::nop for an example that sets
     * up a class method as the callback.)