summaryrefslogtreecommitdiff
path: root/src/libcamera/pipeline_handler.cpp
blob: 54f237942a48a637bc34c3b52afa26470dcb678c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2018, Google Inc.
 *
 * pipeline_handler.cpp - Pipeline handler infrastructure
 */

#include <libcamera/camera.h>
#include <libcamera/camera_manager.h>

#include "log.h"
#include "media_device.h"
#include "pipeline_handler.h"
#include "utils.h"

/**
 * \file pipeline_handler.h
 * \brief Create pipelines and cameras from a set of media devices
 *
 * Each pipeline supported by libcamera needs to be backed by a pipeline
 * handler implementation that operate on a set of media devices. The pipeline
 * handler is responsible for matching the media devices it requires with the
 * devices present in the system, and once all those devices can be acquired,
 * create corresponding Camera instances.
 *
 * Every subclass of PipelineHandler shall be registered with libcamera using
 * the REGISTER_PIPELINE_HANDLER() macro.
 */

namespace libcamera {

LOG_DEFINE_CATEGORY(Pipeline)

/**
 * \class CameraData
 * \brief Base class for platform-specific data associated with a camera
 *
 * The CameraData base abstract class represents platform specific-data
 * a pipeline handler might want to associate with a Camera to access them
 * at a later time.
 *
 * Pipeline handlers are expected to extend this base class with platform
 * specific implementation, associate instances of the derived classes
 * using the setCameraData() method, and access them at a later time
 * with cameraData().
 */

/**
 * \fn CameraData::CameraData(PipelineHandler *pipe)
 * \brief Construct a CameraData instance for the given pipeline handler
 * \param[in] pipe The pipeline handler
 *
 * The reference to the pipeline handler is stored internally, the caller shall
 * guarantee that the pointer remains valid as long as the CameraData instance
 * exists.
 */

/**
 * \var CameraData::camera_
 * \brief The camera related to this CameraData instance
 *
 * The camera_ pointer provides access to the Camera object that this instance
 * is related to. It is set when the Camera is registered with
 * PipelineHandler::registerCamera() and remains valid until the CameraData
 * instance is destroyed.
 */

/**
 * \var CameraData::pipe_
 * \brief The pipeline handler related to this CameraData instance
 *
 * The pipe_ pointer provides access to the PipelineHandler object that this
 * instance is related to. It is set when the CameraData instance is created
 * and remains valid until the instance is destroyed.
 */

/**
 * \class PipelineHandler
 * \brief Create and manage cameras based on a set of media devices
 *
 * The PipelineHandler matches the media devices provided by a DeviceEnumerator
 * with the pipelines it supports and creates corresponding Camera devices.
 *
 * Pipeline handler instances are reference-counted through std::shared_ptr<>.
 * They implement std::enable_shared_from_this<> in order to create new
 * std::shared_ptr<> in code paths originating from member functions of the
 * PipelineHandler class where only the 'this' pointer is available.
 */

/**
 * \brief Construct a PipelineHandler instance
 * \param[in] manager The camera manager
 *
 * In order to honour the std::enable_shared_from_this<> contract,
 * PipelineHandler instances shall never be constructed manually, but always
 * through the PipelineHandlerFactory::create() method implemented by the
 * respective factories.
 */
PipelineHandler::PipelineHandler(CameraManager *manager)
	: manager_(manager)
{
}

PipelineHandler::~PipelineHandler()
{
};

/**
 * \fn PipelineHandler::match(DeviceEnumerator *enumerator)
 * \brief Match media devices and create camera instances
 * \param enumerator The enumerator providing all media devices found in the
 * system
 *
 * This function is the main entry point of the pipeline handler. It is called
 * by the camera manager with the \a enumerator passed as an argument. It shall
 * acquire from the \a enumerator all the media devices it needs for a single
 * pipeline, create one or multiple Camera instances and register them with the
 * camera manager.
 *
 * If all media devices needed by the pipeline handler are found, they must all
 * be acquired by a call to MediaDevice::acquire(). This function shall then
 * create the corresponding Camera instances, store them internally, and return
 * true. Otherwise it shall not acquire any media device (or shall release all
 * the media devices is has acquired by calling MediaDevice::release()) and
 * return false.
 *
 * If multiple instances of a pipeline are available in the system, the
 * PipelineHandler class will be instanciated once per instance, and its match()
 * function called for every instance. Each call shall acquire media devices for
 * one pipeline instance, until all compatible media devices are exhausted.
 *
 * If this function returns true, a new instance of the pipeline handler will
 * be created and its match() function called.
 *
 * \return true if media devices have been acquired and camera instances
 * created, or false otherwise
 */

/**
 * \fn PipelineHandler::streamConfiguration()
 * \brief Retrieve a group of stream configurations for a specified camera
 * \param[in] camera The camera to fetch default configuration from
 * \param[in] streams An array of streams to fetch information about
 *
 * Retrieve the species camera's default configuration for a specified group of
 * streams. The caller shall populate the \a streams array with the streams it
 * wish to fetch the configuration from. The map of streams and configuration
 * returned can then be examined by the caller to learn about the defualt
 * parameters for the specified streams.
 *
 * The intended companion to this is \a configureStreams() which can be used to
 * change the group of streams parameters.
 *
 * \return A map of successfully retrieved streams and configurations or an
 * empty map on error.
 */

/**
 * \fn PipelineHandler::configureStreams()
 * \brief Configure a group of streams for capture
 * \param[in] camera The camera to configure
 * \param[in] config A map of stream configurations to apply
 *
 * Configure the specified group of streams for \a camera according to the
 * configuration specified in \a configs. The intended caller of this interface
 * is the Camera class which will receive configuration to apply from the
 * application.
 *
 * Each pipeline handler implementation is responsible for validating
 * that the configuration requested in \a config can be achieved
 * exactly. Any difference in pixel format, frame size or any other
 * parameter shall result in the -EINVAL error being returned, and no
 * change in configuration being applied to the pipeline. If
 * configuration of a subset of the streams can't be satisfied, the
 * whole configuration is considered invalid.
 *
 * \return 0 on success or a negative error code otherwise
 */

/**
 * \fn PipelineHandler::allocateBuffers()
 * \brief Allocate buffers for a stream
 * \param[in] camera The camera the \a stream belongs to
 * \param[in] stream The stream to allocate buffers for
 *
 * This method allocates buffers internally in the pipeline handler and
 * associates them with the stream's buffer pool.
 *
 * The intended caller of this method is the Camera class.
 *
 * \return 0 on success or a negative error code otherwise
 */

/**
 * \fn PipelineHandler::freeBuffers()
 * \brief Free all buffers associated with a stream
 * \param[in] camera The camera the \a stream belongs to
 * \param[in] stream The stream to free buffers from
 *
 * After a capture session has been stopped all buffers associated with the
 * stream shall be freed.
 *
 * The intended caller of this method is the Camera class.
 *
 * \return 0 on success or a negative error code otherwise
 */

/**
 * \fn PipelineHandler::start()
 * \brief Start capturing from a group of streams
 * \param[in] camera The camera to start
 *
 * Start the group of streams that have been configured for capture by
 * \a configureStreams(). The intended caller of this method is the Camera
 * class which will in turn be called from the application to indicate that it
 * has configured the streams and is ready to capture.
 *
 * \return 0 on success or a negative error code otherwise
 */

/**
 * \fn PipelineHandler::stop()
 * \brief Stop capturing from all running streams
 * \param[in] camera The camera to stop
 *
 * This method stops capturing and processing requests immediately. All pending
 * requests are cancelled and complete immediately in an error state.
 *
 * \todo Complete the pending requests immediately
 */

/**
 * \fn PipelineHandler::queueRequest()
 * \brief Queue a request to the camera
 * \param[in] camera The camera to queue the request to
 * \param[in] request The request to queue
 *
 * This method queues a capture request to the pipeline handler for processing.
 * The request contains a set of buffers associated with streams and a set of
 * parameters. The pipeline handler shall program the device to ensure that the
 * parameters will be applied to the frames captured in the buffers provided in
 * the request.
 *
 * \return 0 on success or a negative error code otherwise
 */

/**
 * \brief Register a camera to the camera manager and pipeline handler
 * \param[in] camera The camera to be added
 * \param[in] data Pipeline-specific data for the camera
 *
 * This method is called by pipeline handlers to register the cameras they
 * handle with the camera manager. It associates the pipeline-specific \a data
 * with the camera, for later retrieval with cameraData(). Ownership of \a data
 * is transferred to the PipelineHandler.
 */
void PipelineHandler::registerCamera(std::shared_ptr<Camera> camera,
				     std::unique_ptr<CameraData> data)
{
	data->camera_ = camera.get();
	cameraData_[camera.get()] = std::move(data);
	cameras_.push_back(camera);
	manager_->addCamera(std::move(camera));
}

/**
 * \brief Enable hotplug handling for a media device
 * \param[in] media The media device
 *
 * This function enables hotplug handling, and especially hot-unplug handling,
 * of the \a media device. It shall be called by pipeline handlers for all the
 * media devices that can be disconnected.
 *
 * When a media device passed to this function is later unplugged, the pipeline
 * handler gets notified and automatically disconnects all the cameras it has
 * registered without requiring any manual intervention.
 */
void PipelineHandler::hotplugMediaDevice(MediaDevice *media)
{
	media->disconnected.connect(this, &PipelineHandler::mediaDeviceDisconnected);
}

/**
 * \brief Slot for the MediaDevice disconnected signal
 */
void PipelineHandler::mediaDeviceDisconnected(MediaDevice *media)
{
	media->disconnected.disconnect(this);

	if (cameras_.empty())
		return;

	disconnect();
}

/**
 * \brief Device disconnection handler
 *
 * This virtual function is called to notify the pipeline handler that the
 * device it handles has been disconnected. It notifies all cameras created by
 * the pipeline handler that they have been disconnected, and unregisters them
 * from the camera manager.
 *
 * The function can be overloaded by pipeline handlers to perform custom
 * operations at disconnection time. Any overloaded version shall call the
 * PipelineHandler::disconnect() base function for proper hot-unplug operation.
 */
void PipelineHandler::disconnect()
{
	for (std::weak_ptr<Camera> ptr : cameras_) {
		std::shared_ptr<Camera> camera = ptr.lock();
		if (!camera)
			continue;

		camera->disconnect();
		manager_->removeCamera(camera.get());
	}

	cameras_.clear();
}

/**
 * \brief Retrieve the pipeline-specific data associated with a Camera
 * \param camera The camera whose data to retrieve
 *
 * \return A pointer to the pipeline-specific data passed to registerCamera().
 * The returned pointer is a borrowed reference and is guaranteed to remain
 * valid until the pipeline handler is destroyed. It shall not be deleted
 * manually by the caller.
 */
CameraData *PipelineHandler::cameraData(const Camera *camera)
{
	ASSERT(cameraData_.count(camera));
	return cameraData_[camera].get();
}

/**
 * \var PipelineHandler::manager_
 * \brief The Camera manager associated with the pipeline handler
 *
 * The camera manager pointer is stored in the pipeline handler for the
 * convenience of pipeline handler implementations. It remains valid and
 * constant for the whole lifetime of the pipeline handler.
 */

/**
 * \class PipelineHandlerFactory
 * \brief Registration of PipelineHandler classes and creation of instances
 *
 * To facilitate discovery and instantiation of PipelineHandler classes, the
 * PipelineHandlerFactory class maintains a registry of pipeline handler
 * classes. Each PipelineHandler subclass shall register itself using the
 * REGISTER_PIPELINE_HANDLER() macro, which will create a corresponding
 * instance of a PipelineHandlerFactory subclass and register it with the
 * static list of factories.
 */

/**
 * \brief Construct a pipeline handler factory
 * \param[in] name Name of the pipeline handler class
 *
 * Creating an instance of the factory registers is with the global list of
 * factories, accessible through the factories() function.
 *
 * The factory \a name is used for debug purpose and shall be unique.
 */
PipelineHandlerFactory::PipelineHandlerFactory(const char *name)
	: name_(name)
{
	registerType(this);
}

/**
 * \fn PipelineHandlerFactory::create()
 * \brief Create an instance of the PipelineHandler corresponding to the factory
 * \param[in] manager The camera manager
 *
 * This virtual function is implemented by the REGISTER_PIPELINE_HANDLER()
 * macro. It creates a pipeline handler instance associated with the camera
 * \a manager.
 *
 * \return a pointer to a newly constructed instance of the PipelineHandler
 * subclass corresponding to the factory
 */

/**
 * \fn PipelineHandlerFactory::name()
 * \brief Retrieve the factory name
 * \return The factory name
 */

/**
 * \brief Add a pipeline handler class to the registry
 * \param[in] factory Factory to use to construct the pipeline handler
 *
 * The caller is responsible to guarantee the uniqueness of the pipeline handler
 * name.
 */
void PipelineHandlerFactory::registerType(PipelineHandlerFactory *factory)
{
	std::vector<PipelineHandlerFactory *> &factories = PipelineHandlerFactory::factories();

	factories.push_back(factory);

	LOG(Pipeline, Debug)
		<< "Registered pipeline handler \"" << factory->name() << "\"";
}

/**
 * \brief Retrieve the list of all pipeline handler factories
 *
 * The static factories map is defined inside the function to ensures it gets
 * initialized on first use, without any dependency on link order.
 *
 * \return the list of pipeline handler factories
 */
std::vector<PipelineHandlerFactory *> &PipelineHandlerFactory::factories()
{
	static std::vector<PipelineHandlerFactory *> factories;
	return factories;
}

/**
 * \def REGISTER_PIPELINE_HANDLER
 * \brief Register a pipeline handler with the pipeline handler factory
 * \param[in] handler Class name of PipelineHandler derived class to register
 *
 * Register a PipelineHandler subclass with the factory and make it available to
 * try and match devices.
 */

} /* namespace libcamera */