#!/usr/bin/env python3 # SPDX-License-Identifier: BSD-3-Clause # Copyright (C) 2022, Tomi Valkeinen # A simple capture example showing: # - How to setup the camera # - Capture certain number of frames in a blocking manner # - How to stop the camera # # This simple example is, in many ways, too simple. The purpose of the example # is to introduce the concepts. A more realistic example is given in # simple-continuous-capture.py. import argparse import libcamera as libcam import selectors import sys # Number of frames to capture TOTAL_FRAMES = 30 def main(): parser = argparse.ArgumentParser() parser.add_argument('-c', '--camera', type=str, default='1', help='Camera index number (starting from 1) or part of the name') parser.add_argument('-f', '--format', type=str, help='Pixel format') parser.add_argument('-s', '--size', type=str, help='Size ("WxH")') args = parser.parse_args() cm = libcam.CameraManager.singleton() try: if args.camera.isnumeric(): cam_idx = int(args.camera) cam = next((cam for i, cam in enumerate(cm.cameras) if i + 1 == cam_idx)) else: cam = next((cam for cam in cm.cameras if args.camera in cam.id)) except Exception: print(f'Failed to find camera "{args.camera}"') return -1 # Acquire the camera for our use ret = cam.acquire() assert ret == 0 # Configure the camera cam_config = cam.generate_configuration([libcam.StreamRole.Viewfinder]) stream_config = cam_config.at(0) if args.format: fmt = libcam.PixelFormat(args.format) stream_config.pixel_format = fmt if args.size: w, h = [int(v) for v in args.size.split('x')] stream_config.size = libcam.Size(w, h) ret = cam.configure(cam_config) assert ret == 0 print(f'Capturing {TOTAL_FRAMES} frames with {stream_config}') stream = stream_config.stream # Allocate the buffers for capture allocator = libcam.FrameBufferAllocator(cam) ret = allocator.allocate(stream) assert ret > 0 num_bufs = len(allocator.buffers(stream)) # Create the requests and assign a buffer for each request reqs = [] for i in range(num_bufs): # Use the buffer index as the cookie req = cam.create_request(i) buffer = allocator.buffers(stream)[i] ret = req.add_buffer(stream, buffer) assert ret == 0 reqs.append(req) # Start the camera ret = cam.start() assert ret == 0 # frames_queued and frames_done track the number of frames queued and done frames_queued = 0 frames_done = 0 # Queue the requests to the camera for req in reqs: ret = cam.queue_request(req) assert ret == 0 frames_queued += 1 # The main loop. Wait for the queued Requests to complete, process them, # and re-queue them again. sel = selectors.DefaultSelector() sel.register(cm.event_fd, selectors.EVENT_READ) while frames_done < TOTAL_FRAMES: # cm.get_ready_requests() does not block, so we use a Selector to wait # for a camera event. Here we should almost always get a single # Request, but in some cases there could be multiple or none. events = sel.select() if not events: continue reqs = cm.get_ready_requests() for req in reqs: frames_done += 1 buffers = req.buffers # A ready Request could contain multiple buffers if multiple streams # were being used. Here we know we only have a single stream, # and we use next(iter()) to get the first and only buffer. assert len(buffers) == 1 stream, fb = next(iter(buffers.items())) # Here we could process the received buffer. In this example we only # print a few details below. meta = fb.metadata print("seq {:3}, bytes {}, frames queued/done {:3}/{:<3}" .format(meta.sequence, '/'.join([str(p.bytes_used) for p in meta.planes]), frames_queued, frames_done)) # If we want to capture more frames we need to queue more Requests. # We could create a totally new Request, but it is more efficient # to reuse the existing one that we just received. if frames_queued < TOTAL_FRAMES: req.reuse() cam.queue_request(req) frames_queued += 1 # Stop the camera ret = cam.stop() assert ret == 0 # Release the camera ret = cam.release() assert ret == 0 return 0 if __name__ == '__main__': sys.exit(main()) ef='#n51'>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 
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * event_dispatcher_poll.cpp - Poll-based event dispatcher
 */

#include "libcamera/internal/event_dispatcher_poll.h"

#include <algorithm>
#include <chrono>
#include <iomanip>
#include <poll.h>
#include <stdint.h>
#include <string.h>
#include <sys/eventfd.h>
#include <unistd.h>

#include <libcamera/event_notifier.h>
#include <libcamera/timer.h>

#include "libcamera/internal/log.h"
#include "libcamera/internal/thread.h"
#include "libcamera/internal/utils.h"

/**
 * \file event_dispatcher_poll.h
 */

namespace libcamera {

LOG_DECLARE_CATEGORY(Event)

static const char *notifierType(EventNotifier::Type type)
{
	if (type == EventNotifier::Read)
		return "read";
	if (type == EventNotifier::Write)
		return "write";
	if (type == EventNotifier::Exception)
		return "exception";

	return "";
}

/**
 * \class EventDispatcherPoll
 * \brief A poll-based event dispatcher
 */

EventDispatcherPoll::EventDispatcherPoll()
	: processingEvents_(false)
{
	/*
	 * Create the event fd. Failures are fatal as we can't implement an
	 * interruptible dispatcher without the fd.
	 */
	eventfd_ = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
	if (eventfd_ < 0)
		LOG(Event, Fatal) << "Unable to create eventfd";
}

EventDispatcherPoll::~EventDispatcherPoll()
{
	close(eventfd_);
}

void EventDispatcherPoll::registerEventNotifier(EventNotifier *notifier)
{
	EventNotifierSetPoll &set = notifiers_[notifier->fd()];
	EventNotifier::Type type = notifier->type();

	if (set.notifiers[type] && set.notifiers[type] != notifier) {
		LOG(Event, Warning)
			<< "Ignoring duplicate " << notifierType(type)
			<< " notifier for fd " << notifier->fd();
		return;
	}

	set.notifiers[type] = notifier;
}

void EventDispatcherPoll::unregisterEventNotifier(EventNotifier *notifier)
{
	auto iter = notifiers_.find(notifier->fd());
	if (iter == notifiers_.end())
		return;

	EventNotifierSetPoll &set = iter->second;
	EventNotifier::Type type = notifier->type();

	if (!set.notifiers[type])
		return;

	if (set.notifiers[type] != notifier) {
		LOG(Event, Warning)
			<< notifierType(type) << " notifier for fd "
			<< notifier->fd() << " is not registered";
		return;
	}

	set.notifiers[type] = nullptr;

	/*
	 * Don't race with event processing if this method is called from an
	 * event notifier. The notifiers_ entry will be erased by
	 * processEvents().
	 */
	if (processingEvents_)
		return;

	if (!set.notifiers[0] && !set.notifiers[1] && !set.notifiers[2])
		notifiers_.erase(iter);
}

void EventDispatcherPoll::registerTimer(Timer *timer)
{
	for (auto iter = timers_.begin(); iter != timers_.end(); ++iter) {
		if ((*iter)->deadline() > timer->deadline()) {
			timers_.insert(iter, timer);
			return;
		}
	}

	timers_.push_back(timer);
}

void EventDispatcherPoll::unregisterTimer(Timer *timer)
{
	for (auto iter = timers_.begin(); iter != timers_.end(); ++iter) {
		if (*iter == timer) {
			timers_.erase(iter);
			return;
		}

		/*
		 * As the timers list is ordered, we can stop as soon as we go
		 * past the deadline.
		 */
		if ((*iter)->deadline() > timer->deadline())
			break;
	}
}

void EventDispatcherPoll::processEvents()
{
	int ret;

	Thread::current()->dispatchMessages();

	/* Create the pollfd array. */
	std::vector<struct pollfd> pollfds;
	pollfds.reserve(notifiers_.size() + 1);

	for (auto notifier : notifiers_)
		pollfds.push_back({ notifier.first, notifier.second.events(), 0 });

	pollfds.push_back({ eventfd_, POLLIN, 0 });

	/* Wait for events and process notifiers and timers. */
	do {
		ret = poll(&pollfds);
	} while (ret == -1 && errno == EINTR);

	if (ret < 0) {
		ret = -errno;
		LOG(Event, Warning) << "poll() failed with " << strerror(-ret);
	} else if (ret > 0) {
		processInterrupt(pollfds.back());
		pollfds.pop_back();
		processNotifiers(pollfds);
	}

	processTimers();
}

void EventDispatcherPoll::interrupt()
{
	uint64_t value = 1;
	ssize_t ret = write(eventfd_, &value, sizeof(value));
	if (ret != sizeof(value)) {
		if (ret < 0)
			ret = -errno;
		LOG(Event, Error)
			<< "Failed to interrupt event dispatcher ("
			<< ret << ")";
	}
}

short EventDispatcherPoll::EventNotifierSetPoll::events() const
{
	short events = 0;

	if (notifiers[EventNotifier::Read])
		events |= POLLIN;
	if (notifiers[EventNotifier::Write])
		events |= POLLOUT;
	if (notifiers[EventNotifier::Exception])
		events |= POLLPRI;

	return events;
}

int EventDispatcherPoll::poll(std::vector<struct pollfd> *pollfds)
{
	/* Compute the timeout. */
	Timer *nextTimer = !timers_.empty() ? timers_.front() : nullptr;
	struct timespec timeout;

	if (nextTimer) {
		utils::time_point now = utils::clock::now();

		if (nextTimer->deadline() > now)
			timeout = utils::duration_to_timespec(nextTimer->deadline() - now);
		else
			timeout = { 0, 0 };

		LOG(Event, Debug)
			<< "timeout " << timeout.tv_sec << "."
			<< std::setfill('0') << std::setw(9)
			<< timeout.tv_nsec;
	}

	return ppoll(pollfds->data(), pollfds->size(),
		     nextTimer ? &timeout : nullptr, nullptr);
}

void EventDispatcherPoll::processInterrupt(const struct pollfd &pfd)
{
	if (!(pfd.revents & POLLIN))
		return;

	uint64_t value;
	ssize_t ret = read(eventfd_, &value, sizeof(value));
	if (ret != sizeof(value)) {
		if (ret < 0)
			ret = -errno;
		LOG(Event, Error)
			<< "Failed to process interrupt (" << ret << ")";
	}
}

void EventDispatcherPoll::processNotifiers(const std::vector<struct pollfd> &pollfds)
{
	static const struct {
		EventNotifier::Type type;
		short events;
	} events[] = {
		{ EventNotifier::Read, POLLIN },
		{ EventNotifier::Write, POLLOUT },
		{ EventNotifier::Exception, POLLPRI },
	};

	processingEvents_ = true;

	for (const pollfd &pfd : pollfds) {
		auto iter = notifiers_.find(pfd.fd);
		ASSERT(iter != notifiers_.end());

		EventNotifierSetPoll &set = iter->second;

		for (const auto &event : events) {
			EventNotifier *notifier = set.notifiers[event.type];

			if (!notifier)
				continue;

			/*
			 * If the file descriptor is invalid, disable the
			 * notifier immediately.
			 */
			if (pfd.revents & POLLNVAL) {
				LOG(Event, Warning)
					<< "Disabling " << notifierType(event.type)
					<< " due to invalid file descriptor "
					<< pfd.fd;
				unregisterEventNotifier(notifier);
				continue;
			}

			if (pfd.revents & event.events)
				notifier->activated.emit(notifier);
		}

		/* Erase the notifiers_ entry if it is now empty. */
		if (!set.notifiers[0] && !set.notifiers[1] && !set.notifiers[2])
			notifiers_.erase(iter);
	}

	processingEvents_ = false;
}

void EventDispatcherPoll::processTimers()
{
	utils::time_point now = utils::clock::now();

	while (!timers_.empty()) {
		Timer *timer = timers_.front();
		if (timer->deadline() > now)
			break;

		timers_.pop_front();
		timer->stop();
		timer->timeout.emit(timer);
	}
}

} /* namespace libcamera */
generated by cgit v1.2.1 (git 2.18.0) at 2025-02-08 09:39:40 +0000