Cppcheck report - Godot - branch: master, commit: 216b3302f318c32a5dcf250293d90e47e712e8e9 (2024-12-22): modules/camera/camera_feed_linux.cpp

/**************************************************************************/
/*  camera_feed_linux.cpp                                                 */
/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#include "camera_feed_linux.h"

#include "servers/rendering_server.h"

#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>

void CameraFeedLinux::update_buffer_thread_func(void *p_func) {
	if (p_func) {
		CameraFeedLinux *camera_feed_linux = (CameraFeedLinux *)p_func;
<--- C-style pointer casting [+]
C-style pointer casting detected. C++ offers four different kinds of casts as replacements: static_cast, const_cast, dynamic_cast and reinterpret_cast. A C-style cast could evaluate to any of those automatically, thus it is considered safer if the programmer explicitly states which kind of cast is expected. See also: https://www.securecoding.cert.org/confluence/display/cplusplus/EXP05-CPP.+Do+not+use+C-style+casts.
		camera_feed_linux->_update_buffer();
	}
}

void CameraFeedLinux::_update_buffer() {
	while (!exit_flag.is_set()) {
		_read_frame();
		usleep(10000);
	}
}

void CameraFeedLinux::_query_device(const String &p_device_name) {
	file_descriptor = open(p_device_name.ascii(), O_RDWR | O_NONBLOCK, 0);
	ERR_FAIL_COND_MSG(file_descriptor == -1, vformat("Cannot open file descriptor for %s. Error: %d.", p_device_name, errno));

	struct v4l2_capability capability;
	if (ioctl(file_descriptor, VIDIOC_QUERYCAP, &capability) == -1) {
		ERR_FAIL_MSG(vformat("Cannot query device. Error: %d.", errno));
	}
	name = String((char *)capability.card);

	for (int index = 0;; index++) {
		struct v4l2_fmtdesc fmtdesc;
		memset(&fmtdesc, 0, sizeof(fmtdesc));
		fmtdesc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		fmtdesc.index = index;

		if (ioctl(file_descriptor, VIDIOC_ENUM_FMT, &fmtdesc) == -1) {
			break;
		}

		for (int res_index = 0;; res_index++) {
			struct v4l2_frmsizeenum frmsizeenum;
			memset(&frmsizeenum, 0, sizeof(frmsizeenum));
			frmsizeenum.pixel_format = fmtdesc.pixelformat;
			frmsizeenum.index = res_index;

			if (ioctl(file_descriptor, VIDIOC_ENUM_FRAMESIZES, &frmsizeenum) == -1) {
				break;
			}

			for (int framerate_index = 0;; framerate_index++) {
				struct v4l2_frmivalenum frmivalenum;
				memset(&frmivalenum, 0, sizeof(frmivalenum));
				frmivalenum.pixel_format = fmtdesc.pixelformat;
				frmivalenum.width = frmsizeenum.discrete.width;
				frmivalenum.height = frmsizeenum.discrete.height;
				frmivalenum.index = framerate_index;

				if (ioctl(file_descriptor, VIDIOC_ENUM_FRAMEINTERVALS, &frmivalenum) == -1) {
					if (framerate_index == 0) {
						_add_format(fmtdesc, frmsizeenum.discrete, -1, 1);
					}
					break;
				}

				_add_format(fmtdesc, frmsizeenum.discrete, frmivalenum.discrete.numerator, frmivalenum.discrete.denominator);
			}
		}
	}

	close(file_descriptor);
}

void CameraFeedLinux::_add_format(v4l2_fmtdesc p_description, v4l2_frmsize_discrete p_size, int p_frame_numerator, int p_frame_denominator) {
	FeedFormat feed_format;
	feed_format.width = p_size.width;
	feed_format.height = p_size.height;
	feed_format.format = String((char *)p_description.description);
	feed_format.frame_numerator = p_frame_numerator;
	feed_format.frame_denominator = p_frame_denominator;
	feed_format.pixel_format = p_description.pixelformat;
	print_verbose(vformat("%s %dx%d@%d/%dfps", (char *)p_description.description, p_size.width, p_size.height, p_frame_denominator, p_frame_numerator));
	formats.push_back(feed_format);
}

bool CameraFeedLinux::_request_buffers() {
	struct v4l2_requestbuffers requestbuffers;

	memset(&requestbuffers, 0, sizeof(requestbuffers));
	requestbuffers.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	requestbuffers.memory = V4L2_MEMORY_MMAP;
	requestbuffers.count = 4;

	if (ioctl(file_descriptor, VIDIOC_REQBUFS, &requestbuffers) == -1) {
		ERR_FAIL_V_MSG(false, vformat("ioctl(VIDIOC_REQBUFS) error: %d.", errno));
	}

	ERR_FAIL_COND_V_MSG(requestbuffers.count < 2, false, "Not enough buffers granted.");

	buffer_count = requestbuffers.count;
	buffers = new StreamingBuffer[buffer_count];

	for (unsigned int i = 0; i < buffer_count; i++) {
		struct v4l2_buffer buffer;

		memset(&buffer, 0, sizeof(buffer));
		buffer.type = requestbuffers.type;
		buffer.memory = V4L2_MEMORY_MMAP;
		buffer.index = i;

		if (ioctl(file_descriptor, VIDIOC_QUERYBUF, &buffer) == -1) {
			delete[] buffers;
			ERR_FAIL_V_MSG(false, vformat("ioctl(VIDIOC_QUERYBUF) error: %d.", errno));
		}

		buffers[i].length = buffer.length;
		buffers[i].start = mmap(nullptr, buffer.length, PROT_READ | PROT_WRITE, MAP_SHARED, file_descriptor, buffer.m.offset);

		if (buffers[i].start == MAP_FAILED) {
			for (unsigned int b = 0; b < i; b++) {
				_unmap_buffers(i);
			}
			delete[] buffers;
			ERR_FAIL_V_MSG(false, "Mapping buffers failed.");
		}
	}

	return true;
}

bool CameraFeedLinux::_start_capturing() {
	for (unsigned int i = 0; i < buffer_count; i++) {
		struct v4l2_buffer buffer;

		memset(&buffer, 0, sizeof(buffer));
		buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		buffer.memory = V4L2_MEMORY_MMAP;
		buffer.index = i;

		if (ioctl(file_descriptor, VIDIOC_QBUF, &buffer) == -1) {
			ERR_FAIL_V_MSG(false, vformat("ioctl(VIDIOC_QBUF) error: %d.", errno));
		}
	}

	enum v4l2_buf_type type;
	type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

	if (ioctl(file_descriptor, VIDIOC_STREAMON, &type) == -1) {
		ERR_FAIL_V_MSG(false, vformat("ioctl(VIDIOC_STREAMON) error: %d.", errno));
	}

	return true;
}

void CameraFeedLinux::_read_frame() {
	struct v4l2_buffer buffer;
	memset(&buffer, 0, sizeof(buffer));
	buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	buffer.memory = V4L2_MEMORY_MMAP;

	if (ioctl(file_descriptor, VIDIOC_DQBUF, &buffer) == -1) {
		if (errno != EAGAIN) {
			print_error(vformat("ioctl(VIDIOC_DQBUF) error: %d.", errno));
			exit_flag.set();
		}
		return;
	}

	buffer_decoder->decode(buffers[buffer.index]);

	if (ioctl(file_descriptor, VIDIOC_QBUF, &buffer) == -1) {
		print_error(vformat("ioctl(VIDIOC_QBUF) error: %d.", errno));
	}

	emit_signal(SNAME("frame_changed"));
}

void CameraFeedLinux::_stop_capturing() {
	enum v4l2_buf_type type;
	type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

	if (ioctl(file_descriptor, VIDIOC_STREAMOFF, &type) == -1) {
		print_error(vformat("ioctl(VIDIOC_STREAMOFF) error: %d.", errno));
	}
}

void CameraFeedLinux::_unmap_buffers(unsigned int p_count) {
	for (unsigned int i = 0; i < p_count; i++) {
		munmap(buffers[i].start, buffers[i].length);
	}
}

void CameraFeedLinux::_start_thread() {
	exit_flag.clear();
	thread = memnew(Thread);
	thread->start(CameraFeedLinux::update_buffer_thread_func, this);
}

String CameraFeedLinux::get_device_name() const {
	return device_name;
}

bool CameraFeedLinux::activate_feed() {
	ERR_FAIL_COND_V_MSG(selected_format == -1, false, "CameraFeed format needs to be set before activating.");
	file_descriptor = open(device_name.ascii(), O_RDWR | O_NONBLOCK, 0);
	if (_request_buffers() && _start_capturing()) {
		buffer_decoder = _create_buffer_decoder();
		_start_thread();
		return true;
	}
	ERR_FAIL_V_MSG(false, "Could not activate feed.");
}

BufferDecoder *CameraFeedLinux::_create_buffer_decoder() {
	switch (formats[selected_format].pixel_format) {
		case V4L2_PIX_FMT_MJPEG:
		case V4L2_PIX_FMT_JPEG:
			return memnew(JpegBufferDecoder(this));
		case V4L2_PIX_FMT_YUYV:
		case V4L2_PIX_FMT_YYUV:
		case V4L2_PIX_FMT_YVYU:
		case V4L2_PIX_FMT_UYVY:
		case V4L2_PIX_FMT_VYUY: {
			String output = parameters["output"];
			if (output == "separate") {
				return memnew(SeparateYuyvBufferDecoder(this));
			}
			if (output == "grayscale") {
				return memnew(YuyvToGrayscaleBufferDecoder(this));
			}
			if (output == "copy") {
				return memnew(CopyBufferDecoder(this, false));
			}
			return memnew(YuyvToRgbBufferDecoder(this));
		}
		default:
			return memnew(CopyBufferDecoder(this, true));
	}
}

void CameraFeedLinux::deactivate_feed() {
	exit_flag.set();
	thread->wait_to_finish();
	memdelete(thread);
	_stop_capturing();
	_unmap_buffers(buffer_count);
	delete[] buffers;
	memdelete(buffer_decoder);
	for (int i = 0; i < CameraServer::FEED_IMAGES; i++) {
		RID placeholder = RenderingServer::get_singleton()->texture_2d_placeholder_create();
		RenderingServer::get_singleton()->texture_replace(texture[i], placeholder);
	}
	base_width = 0;
	base_height = 0;
	close(file_descriptor);

	emit_signal(SNAME("format_changed"));
}

Array CameraFeedLinux::get_formats() const {
	Array result;
	for (const FeedFormat &format : formats) {
		Dictionary dictionary;
		dictionary["width"] = format.width;
		dictionary["height"] = format.height;
		dictionary["format"] = format.format;
		dictionary["frame_numerator"] = format.frame_numerator;
		dictionary["frame_denominator"] = format.frame_denominator;
		result.push_back(dictionary);
	}
	return result;
}

CameraFeed::FeedFormat CameraFeedLinux::get_format() const {
	FeedFormat feed_format = {};
	return selected_format == -1 ? feed_format : formats[selected_format];
}

bool CameraFeedLinux::set_format(int p_index, const Dictionary &p_parameters) {
	ERR_FAIL_COND_V_MSG(active, false, "Feed is active.");
	ERR_FAIL_INDEX_V_MSG(p_index, formats.size(), false, "Invalid format index.");

	FeedFormat feed_format = formats[p_index];

	file_descriptor = open(device_name.ascii(), O_RDWR | O_NONBLOCK, 0);

	struct v4l2_format format;
	memset(&format, 0, sizeof(format));
	format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	format.fmt.pix.width = feed_format.width;
	format.fmt.pix.height = feed_format.height;
	format.fmt.pix.pixelformat = feed_format.pixel_format;

	if (ioctl(file_descriptor, VIDIOC_S_FMT, &format) == -1) {
		close(file_descriptor);
		ERR_FAIL_V_MSG(false, vformat("Cannot set format, error: %d.", errno));
	}

	if (feed_format.frame_numerator > 0) {
		struct v4l2_streamparm param;
		memset(&param, 0, sizeof(param));

		param.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		param.parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
		param.parm.capture.timeperframe.numerator = feed_format.frame_numerator;
		param.parm.capture.timeperframe.denominator = feed_format.frame_denominator;

		if (ioctl(file_descriptor, VIDIOC_S_PARM, &param) == -1) {
			close(file_descriptor);
			ERR_FAIL_V_MSG(false, vformat("Cannot set framerate, error: %d.", errno));
		}
	}
	close(file_descriptor);

	parameters = p_parameters.duplicate();
	selected_format = p_index;
	emit_signal(SNAME("format_changed"));

	return true;
}

CameraFeedLinux::CameraFeedLinux(const String &p_device_name) :
		CameraFeed() {
	device_name = p_device_name;
<--- Variable 'device_name' is assigned in constructor body. Consider performing initialization in initialization list. [+]
When an object of a class is created, the constructors of all member variables are called consecutively in the order the variables are declared, even if you don't explicitly write them to the initialization list. You could avoid assigning 'device_name' a value by passing the value to the constructor in the initialization list.
	_query_device(device_name);
}

CameraFeedLinux::~CameraFeedLinux() {
	if (is_active()) {
		deactivate_feed();
	}
}