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;
122 /** Return the port-property value and type for a given key.
123 * (eg query a human readable port name)
125 * The API follows jack_get_property():
127 * @param key The key of the property to retrieve
128 * @param value Set to the value of the property if found
129 * @param type The type of the property if set (
130 * Type of data, either a MIME type or URI.
131 * If type is empty, the data is assumed to be a UTF-8 encoded string.
133 * @return 0 on success, -1 if the @p subject has no @p key property.
135 * for available keys, see
136 * https://github.com/jackaudio/headers/blob/master/metadata.h
137 * https://github.com/drobilla/jackey/blob/master/jackey.h
139 virtual int get_port_property (PortHandle, const std::string& key, std::string& value, std::string& type) const { return -1; }
141 /** Set the port-property value and type for a given key
143 * The API follows jack_set_property():
144 * @param key The key of the property.
145 * @param value The value of the property.
146 * @param type The type of the property.
148 * @return 0 on success, -1 on error
150 virtual int set_port_property (PortHandle, const std::string& key, const std::string& value, const std::string& type) { return -1; }
152 /** Return a reference to a port with the fullname @param name. Return
153 * an "empty" PortHandle (analogous to a null pointer) if no such port exists.
155 virtual PortHandle get_port_by_name (const std::string&) const = 0;
157 /** Find the set of ports whose names, types and flags match
158 * specified values, place the names of each port into @param ports,
159 * and return the count of the number found.
161 * To avoid selecting by name, pass an empty string for @param
164 * To avoid selecting by type, pass DataType::NIL as @param type.
166 * To avoid selecting by flags, pass PortFlags (0) as @param flags.
168 virtual int get_ports (const std::string& port_name_pattern, DataType type, PortFlags flags, std::vector<std::string>& ports) const = 0;
170 /** Return the Ardour data type handled by the port referred to by @param
171 * port. Returns DataType::NIL if the port does not exist.
173 virtual DataType port_data_type (PortHandle port) const = 0;
175 /** Create a new port whose fullname will be the conjuction of my_name(),
176 * ":" and @param shortname. The port will handle data specified by @param
177 * type and will have the flags given by @param flags. If successfull,
178 * return a reference to the port, otherwise return a null pointer.
180 virtual PortHandle register_port (const std::string& shortname, ARDOUR::DataType type, ARDOUR::PortFlags flags) = 0;
182 /* Destroy the port referred to by @param port, including all resources
183 * associated with it. This will also disconnect @param port from any ports it
186 virtual void unregister_port (PortHandle) = 0;
188 /* Connection management */
190 /** Ensure that data written to the port named by @param src will be
191 * readable from the port named by @param dst. Return zero on success,
192 * non-zero otherwise.
194 virtual int connect (const std::string& src, const std::string& dst) = 0;
196 /** Remove any existing connection between the ports named by @param src and
197 * @param dst. Return zero on success, non-zero otherwise.
199 virtual int disconnect (const std::string& src, const std::string& dst) = 0;
202 /** Ensure that data written to the port referenced by @param portwill be
203 * readable from the port named by @param dst. Return zero on success,
204 * non-zero otherwise.
206 virtual int connect (PortHandle src, const std::string& dst) = 0;
207 /** Remove any existing connection between the port referenced by @param src and
208 * the port named @param dst. Return zero on success, non-zero otherwise.
210 virtual int disconnect (PortHandle src, const std::string& dst) = 0;
212 /** Remove all connections between the port referred to by @param port and
213 * any other ports. Return zero on success, non-zero otherwise.
215 virtual int disconnect_all (PortHandle port) = 0;
217 /** Return true if the port referred to by @param port has any connections
218 * to other ports. Return false otherwise.
220 virtual bool connected (PortHandle port, bool process_callback_safe = true) = 0;
221 /** Return true if the port referred to by @param port is connected to
222 * the port named by @param name. Return false otherwise.
224 virtual bool connected_to (PortHandle, const std::string& name, bool process_callback_safe = true) = 0;
226 /** Return true if the port referred to by @param port has any connections
227 * to ports marked with the PortFlag IsPhysical. Return false otherwise.
229 virtual bool physically_connected (PortHandle port, bool process_callback_safe = true) = 0;
231 /** Place the names of all ports connected to the port named by @param
232 * ports into @param names, and return the number of connections.
234 virtual int get_connections (PortHandle port, std::vector<std::string>& names, bool process_callback_safe = true) = 0;
238 /** Retrieve a MIDI event from the data at @param port_buffer. The event
239 number to be retrieved is given by @param event_index (a value of zero
240 indicates that the first event in the port_buffer should be retrieved).
242 * The data associated with the event will be copied into the buffer at
243 * @param buf and the number of bytes written will be stored in @param
244 * size. The timestamp of the event (which is always relative to the start
245 * of the current process cycle, in samples) will be stored in @param
248 virtual int midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** buf, void* port_buffer, uint32_t event_index) = 0;
250 /** Place a MIDI event consisting of @param size bytes copied from the data
251 * at @param buf into the port buffer referred to by @param
252 * port_buffer. The MIDI event will be marked with a time given by @param
253 * timestamp. Return zero on success, non-zero otherwise.
255 * Events must be added monotonically to a port buffer. An attempt to
256 * add a non-monotonic event (e.g. out-of-order) will cause this method
257 * to return a failure status.
259 virtual int midi_event_put (void* port_buffer, pframes_t timestamp, const uint8_t* buffer, size_t size) = 0;
261 /** Return the number of MIDI events in the data at @param port_buffer
263 virtual uint32_t get_midi_event_count (void* port_buffer) = 0;
265 /** Clear the buffer at @param port_buffer of all MIDI events.
267 * After a call to this method, an immediate, subsequent call to
268 * get_midi_event_count() with the same @param port_buffer argument must
271 virtual void midi_clear (void* port_buffer) = 0;
275 /** Return true if the implementation can offer input monitoring.
277 * Input monitoring involves the (selective) routing of incoming data
278 * to an outgoing data stream, without the data being passed to the CPU.
280 * Only certain audio hardware can provide this, and only certain audio
283 virtual bool can_monitor_input() const = 0;
284 /** Increment or decrement the number of requests to monitor the input
285 * of the hardware channel represented by the port referred to by @param
288 * If the number of requests rises above zero, input monitoring will
289 * be enabled (if can_monitor_input() returns true for the implementation).
291 * If the number of requests falls to zero, input monitoring will be
292 * disabled (if can_monitor_input() returns true for the implementation)
294 virtual int request_input_monitoring (PortHandle port, bool yn) = 0;
295 /* Force input monitoring of the hardware channel represented by the port
296 * referred to by @param port to be on or off, depending on the true/false
297 * status of @param yn. The request count is ignored when using this
298 * method, so if this is called with yn set to false, input monitoring will
299 * be disabled regardless of the number of requests to enable it.
301 virtual int ensure_input_monitoring (PortHandle port, bool yn) = 0;
302 /** Return true if input monitoring is enabled for the hardware channel
303 * represented by the port referred to by @param port. Return false
306 virtual bool monitoring_input (PortHandle port) = 0;
308 /* Latency management
311 /** Set the latency range for the port referred to by @param port to @param
312 * r. The playback range will be set if @param for_playback is true,
313 * otherwise the capture range will be set.
315 virtual void set_latency_range (PortHandle port, bool for_playback, LatencyRange r) = 0;
316 /** Return the latency range for the port referred to by @param port.
317 * The playback range will be returned if @param for_playback is true,
318 * otherwise the capture range will be returned.
320 virtual LatencyRange get_latency_range (PortHandle port, bool for_playback) = 0;
322 /* Discovering physical ports */
324 /** Return true if the port referred to by @param port has the IsPhysical
325 * flag set. Return false otherwise.
327 virtual bool port_is_physical (PortHandle port) const = 0;
329 /** Store into @param names the names of all ports with the IsOutput and
330 * IsPhysical flag set, that handle data of type @param type.
332 * This can be used to discover outputs associated with hardware devices.
334 virtual void get_physical_outputs (DataType type, std::vector<std::string>& names) = 0;
335 /** Store into @param names the names of all ports with the IsInput and
336 * IsPhysical flags set, that handle data of type @param type.
338 * This can be used to discover inputs associated with hardware devices.
340 virtual void get_physical_inputs (DataType type, std::vector<std::string>& names) = 0;
341 /** Return the total count (possibly mixed between different data types)
342 of the number of ports with the IsPhysical and IsOutput flags set.
344 virtual ChanCount n_physical_outputs () const = 0;
345 /** Return the total count (possibly mixed between different data types)
346 of the number of ports with the IsPhysical and IsInput flags set.
348 virtual ChanCount n_physical_inputs () const = 0;
350 /** Return the address of the memory area where data for the port can be
351 * written (if the port has the PortFlag IsOutput set) or read (if the port
352 * has the PortFlag IsInput set).
354 * The return value is untyped because buffers containing different data
355 * depending on the port type.
357 virtual void* get_buffer (PortHandle, pframes_t) = 0;
359 /* MIDI ports (the ones in libmidi++) need this to be able to correctly
360 * schedule MIDI events within their buffers. It is a bit odd that we
361 * expose this here, because it is also exposed by AudioBackend, but they
362 * only have access to a PortEngine object, not an AudioBackend.
364 * Return the time according to the sample clock in use when the current
365 * buffer process cycle began.
367 * XXX to be removed after some more design cleanup.
369 virtual framepos_t sample_time_at_cycle_start () = 0;
372 PortManager& manager;
377 #endif /* __libardour_port_engine_h__ */