2 Copyright (C) 2013 Paul Davis
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #ifndef __libardour_port_engine_h__
21 #define __libardour_port_engine_h__
28 #include "ardour/data_type.h"
29 #include "ardour/libardour_visibility.h"
30 #include "ardour/types.h"
36 /** PortEngine is an abstract base class that defines the functionality
39 * A Port is basically an endpoint for a datastream (which can either be
40 * continuous, like audio, or event-based, like MIDI). Ports have buffers
41 * associated with them into which data can be written (if they are output
42 * ports) and from which data can be read (if they input ports). Ports can be
43 * connected together so that data written to an output port can be read from
44 * an input port. These connections can be 1:1, 1:N OR N:1.
46 * Ports may be associated with software only, or with hardware. Hardware
47 * related ports are often referred to as physical, and correspond to some
48 * relevant physical entity on a hardware device, such as an audio jack or a
49 * MIDI connector. Physical ports may be potentially asked to monitor their
50 * inputs, though some implementations may not support this.
52 * Most physical ports will also be considered "terminal", which means that
53 * data delivered there or read from there will go to or comes from a system
54 * outside of the PortEngine implementation's control (e.g. the analog domain
55 * for audio, or external MIDI devices for MIDI). Non-physical ports can also
56 * be considered "terminal". For example, the output port of a software
57 * synthesizer is a terminal port, because the data contained in its buffer
58 * does not and cannot be considered to come from any other port - it is
59 * synthesized by its owner.
61 * Ports also have latency associated with them. Each port has a playback
62 * latency and a capture latency:
64 * <b>capture latency</b>: how long since the data read from the buffer of a
65 * port arrived at at a terminal port. The data will have
66 * come from the "outside world" if the terminal port is also
67 * physical, or will have been synthesized by the entity that
68 * owns the terminal port.
70 * <b>playback latency</b>: how long until the data written to the buffer of
71 * port will reach a terminal port.
74 * For more detailed questions about the PortEngine API, consult the JACK API
75 * documentation, on which this entire object is based.
78 class LIBARDOUR_API PortEngine {
80 PortEngine (PortManager& pm) : manager (pm) {}
81 virtual ~PortEngine() {}
83 /** Return a private, type-free pointer to any data
84 * that might be useful to a concrete implementation
86 virtual void* private_handle() const = 0;
88 /* We use void* here so that the API can be defined for any implementation.
90 * We could theoretically use a template (PortEngine<T>) and define
91 * PortHandle as T, but this complicates the desired inheritance
92 * pattern in which FooPortEngine handles things for the Foo API,
93 * rather than being a derivative of PortEngine<Foo>.
96 typedef void* PortHandle;
98 /** Return the name of this process as used by the port manager
101 virtual const std::string& my_name() const = 0;
103 /** Return true if the underlying mechanism/API is still available
104 * for us to utilize. return false if some or all of the AudioBackend
105 * API can no longer be effectively used.
107 virtual bool available() const = 0;
109 /** Return the maximum size of a port name
111 virtual uint32_t port_name_size() const = 0;
113 /** Returns zero if the port referred to by @param port was set to @param
114 * name. Return non-zero otherwise.
116 virtual int set_port_name (PortHandle port, const std::string& name) = 0;
117 /** Return the name of the port referred to by @param port. If the port
118 * does not exist, return an empty string.
120 virtual std::string get_port_name (PortHandle) const = 0;
121 /** Return a reference to a port with the fullname @param name. Return
122 * a null pointer if no such port exists.
124 virtual PortHandle* get_port_by_name (const std::string&) const = 0;
126 /** Find the set of ports whose names, types and flags match
127 * specified values, place the names of each port into @param ports,
128 * and return the count of the number found.
130 * To avoid selecting by name, pass an empty string for @param
133 * To avoid selecting by type, pass DataType::NIL as @param type.
135 * To avoid selecting by flags, pass PortFlags (0) as @param flags.
137 virtual int get_ports (const std::string& port_name_pattern, DataType type, PortFlags flags, std::vector<std::string>& ports) const = 0;
139 /** Return the Ardour data type handled by the port referred to by @param
140 * port. Returns DataType::NIL if the port does not exist.
142 virtual DataType port_data_type (PortHandle port) const = 0;
144 /** Create a new port whose fullname will be the conjuction of my_name(),
145 * ":" and @param shortname. The port will handle data specified by @param
146 * type and will have the flags given by @param flags. If successfull,
147 * return a reference to the port, otherwise return a null pointer.
149 virtual PortHandle register_port (const std::string& shortname, ARDOUR::DataType type, ARDOUR::PortFlags flags) = 0;
151 /* Destroy the port referred to by @param port, including all resources
152 * associated with it. This will also disconnect @param port from any ports it
155 virtual void unregister_port (PortHandle) = 0;
157 /* Connection management */
159 /** Ensure that data written to the port named by @param src will be
160 * readable from the port named by @param dst. Return zero on success,
161 * non-zero otherwise.
163 virtual int connect (const std::string& src, const std::string& dst) = 0;
165 /** Remove any existing connection between the ports named by @param src and
166 * @param dst. Return zero on success, non-zero otherwise.
168 virtual int disconnect (const std::string& src, const std::string& dst) = 0;
171 /** Ensure that data written to the port referenced by @param portwill be
172 * readable from the port named by @param dst. Return zero on success,
173 * non-zero otherwise.
175 virtual int connect (PortHandle src, const std::string& dst) = 0;
176 /** Remove any existing connection between the port referenced by @param src and
177 * the port named @param dst. Return zero on success, non-zero otherwise.
179 virtual int disconnect (PortHandle src, const std::string& dst) = 0;
181 /** Remove all connections between the port referred to by @param port and
182 * any other ports. Return zero on success, non-zero otherwise.
184 virtual int disconnect_all (PortHandle port) = 0;
186 /** Return true if the port referred to by @param port has any connections
187 * to other ports. Return false otherwise.
189 virtual bool connected (PortHandle port, bool process_callback_safe = true) = 0;
190 /** Return true if the port referred to by @param port is connected to
191 * the port named by @param name. Return false otherwise.
193 virtual bool connected_to (PortHandle, const std::string& name, bool process_callback_safe = true) = 0;
195 /** Return true if the port referred to by @param port has any connections
196 * to ports marked with the PortFlag IsPhysical. Return false otherwise.
198 virtual bool physically_connected (PortHandle port, bool process_callback_safe = true) = 0;
200 /** Place the names of all ports connected to the port named by @param
201 * ports into @param names, and return the number of connections.
203 virtual int get_connections (PortHandle port, std::vector<std::string>& names, bool process_callback_safe = true) = 0;
207 /** Retrieve a MIDI event from the data at @param port_buffer. The event
208 number to be retrieved is given by @param event_index (a value of zero
209 indicates that the first event in the port_buffer should be retrieved).
211 * The data associated with the event will be copied into the buffer at
212 * @param buf and the number of bytes written will be stored in @param
213 * size. The timestamp of the event (which is always relative to the start
214 * of the current process cycle, in samples) will be stored in @param
217 virtual int midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** buf, void* port_buffer, uint32_t event_index) = 0;
219 /** Place a MIDI event consisting of @param size bytes copied from the data
220 * at @param buf into the port buffer referred to by @param
221 * port_buffer. The MIDI event will be marked with a time given by @param
222 * timestamp. Return zero on success, non-zero otherwise.
224 * Events must be added monotonically to a port buffer. An attempt to
225 * add a non-monotonic event (e.g. out-of-order) will cause this method
226 * to return a failure status.
228 virtual int midi_event_put (void* port_buffer, pframes_t timestamp, const uint8_t* buffer, size_t size) = 0;
230 /** Return the number of MIDI events in the data at @param port_buffer
232 virtual uint32_t get_midi_event_count (void* port_buffer) = 0;
234 /** Clear the buffer at @param port_buffer of all MIDI events.
236 * After a call to this method, an immediate, subsequent call to
237 * get_midi_event_count() with the same @param port_buffer argument must
240 virtual void midi_clear (void* port_buffer) = 0;
244 /** Return true if the implementation can offer input monitoring.
246 * Input monitoring involves the (selective) routing of incoming data
247 * to an outgoing data stream, without the data being passed to the CPU.
249 * Only certain audio hardware can provide this, and only certain audio
252 virtual bool can_monitor_input() const = 0;
253 /** Increment or decrement the number of requests to monitor the input
254 * of the hardware channel represented by the port referred to by @param
257 * If the number of requests rises above zero, input monitoring will
258 * be enabled (if can_monitor_input() returns true for the implementation).
260 * If the number of requests falls to zero, input monitoring will be
261 * disabled (if can_monitor_input() returns true for the implementation)
263 virtual int request_input_monitoring (PortHandle port, bool yn) = 0;
264 /* Force input monitoring of the hardware channel represented by the port
265 * referred to by @param port to be on or off, depending on the true/false
266 * status of @param yn. The request count is ignored when using this
267 * method, so if this is called with yn set to false, input monitoring will
268 * be disabled regardless of the number of requests to enable it.
270 virtual int ensure_input_monitoring (PortHandle port, bool yn) = 0;
271 /** Return true if input monitoring is enabled for the hardware channel
272 * represented by the port referred to by @param port. Return false
275 virtual bool monitoring_input (PortHandle port) = 0;
277 /* Latency management
280 /** Set the latency range for the port referred to by @param port to @param
281 * r. The playback range will be set if @param for_playback is true,
282 * otherwise the capture range will be set.
284 virtual void set_latency_range (PortHandle port, bool for_playback, LatencyRange r) = 0;
285 /** Return the latency range for the port referred to by @param port.
286 * The playback range will be returned if @param for_playback is true,
287 * otherwise the capture range will be returned.
289 virtual LatencyRange get_latency_range (PortHandle port, bool for_playback) = 0;
291 /* Discovering physical ports */
293 /** Return true if the port referred to by @param port has the IsPhysical
294 * flag set. Return false otherwise.
296 virtual bool port_is_physical (PortHandle port) const = 0;
298 /** Store into @param names the names of all ports with the IsOutput and
299 * IsPhysical flag set, that handle data of type @param type.
301 * This can be used to discover outputs associated with hardware devices.
303 virtual void get_physical_outputs (DataType type, std::vector<std::string>& names) = 0;
304 /** Store into @param names the names of all ports with the IsInput and
305 * IsPhysical flags set, that handle data of type @param type.
307 * This can be used to discover inputs associated with hardware devices.
309 virtual void get_physical_inputs (DataType type, std::vector<std::string>& names) = 0;
310 /** Return the total count (possibly mixed between different data types)
311 of the number of ports with the IsPhysical and IsOutput flags set.
313 virtual ChanCount n_physical_outputs () const = 0;
314 /** Return the total count (possibly mixed between different data types)
315 of the number of ports with the IsPhysical and IsInput flags set.
317 virtual ChanCount n_physical_inputs () const = 0;
319 /** Return the address of the memory area where data for the port can be
320 * written (if the port has the PortFlag IsOutput set) or read (if the port
321 * has the PortFlag IsInput set).
323 * The return value is untyped because buffers containing different data
324 * depending on the port type.
326 virtual void* get_buffer (PortHandle, pframes_t) = 0;
328 /* MIDI ports (the ones in libmidi++) need this to be able to correctly
329 * schedule MIDI events within their buffers. It is a bit odd that we
330 * expose this here, because it is also exposed by AudioBackend, but they
331 * only have access to a PortEngine object, not an AudioBackend.
333 * Return the time according to the sample clock in use when the current
334 * buffer process cycle began.
336 * XXX to be removed after some more design cleanup.
338 virtual pframes_t sample_time_at_cycle_start () = 0;
341 PortManager& manager;
346 #endif /* __libardour_port_engine_h__ */