[pulseview.git] / pv / devicemanager.cpp

/*
 * This file is part of the PulseView project.
 *
 * Copyright (C) 2013 Joel Holdsworth <joel@airwebreathe.org.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "devicemanager.hpp"
#include "session.hpp"

#include <cassert>
#include <functional>
#include <memory>
#include <sstream>
#include <stdexcept>
#include <string>

#include <libsigrokcxx/libsigrokcxx.hpp>

#include <QApplication>
#include <QDebug>
#include <QObject>
#include <QProgressDialog>

#include <boost/filesystem.hpp>

#include <pv/devices/hardwaredevice.hpp>
#include <pv/util.hpp>

using std::bind;
using std::list;
using std::map;
using std::placeholders::_1;
using std::placeholders::_2;
using std::shared_ptr;
using std::string;
using std::unique_ptr;
using std::vector;

using Glib::VariantBase;

using sigrok::ConfigKey;
using sigrok::Context;
using sigrok::Driver;

namespace pv {

DeviceManager::DeviceManager(shared_ptr<Context> context,
	std::string driver, bool do_scan) :
	context_(context)
{
	unique_ptr<QProgressDialog> progress(new QProgressDialog("",
		QObject::tr("Cancel"), 0, context->drivers().size() + 1));
	progress->setWindowModality(Qt::WindowModal);
	progress->setMinimumDuration(1);  // To show the dialog immediately

	int entry_num = 1;

	/*
	 * Check the presence of an optional user spec for device scans.
	 * Determine the driver name and options (in generic format) when
	 * applicable.
	 */
	std::string user_name;
	vector<std::string> user_opts;
	if (!driver.empty()) {
		user_opts = pv::util::split_string(driver, ":");
		user_name = user_opts.front();
		user_opts.erase(user_opts.begin());
	}

	/*
	 * Scan for devices. No specific options apply here, this is
	 * best effort auto detection.
	 */
	for (auto& entry : context->drivers()) {
		if (!do_scan)
			break;

		// Skip drivers we won't scan anyway
		if (!driver_supported(entry.second))
			continue;

		progress->setLabelText(QObject::tr("Scanning for devices that driver %1 can access...")
			.arg(QString::fromStdString(entry.first)));

		if (entry.first == user_name)
			continue;
		driver_scan(entry.second, map<const ConfigKey *, VariantBase>());

		progress->setValue(entry_num++);
		QApplication::processEvents();
		if (progress->wasCanceled())
			break;
	}

	/*
	 * Optionally run another scan with potentially more specific
	 * options when requested by the user. This is motivated by
	 * several different uses: It can find devices that are not
	 * covered by the above auto detection (UART, TCP). It can
	 * prefer one out of multiple found devices, and have this
	 * device pre-selected for new sessions upon user's request.
	 */
	user_spec_device_.reset();
	if (!driver.empty()) {
		shared_ptr<sigrok::Driver> scan_drv;
		map<const ConfigKey *, VariantBase> scan_opts;

		/*
		 * Lookup the device driver name.
		 */
		map<string, shared_ptr<Driver>> drivers = context->drivers();
		auto entry = drivers.find(user_name);
		scan_drv = (entry != drivers.end()) ? entry->second : nullptr;

		/*
		 * Convert generic string representation of options
		 * to the driver specific data types.
		 */
		if (scan_drv && !user_opts.empty()) {
			auto drv_opts = scan_drv->scan_options();
			scan_opts = drive_scan_options(user_opts, drv_opts);
		}

		/*
		 * Run another scan for the specified driver, passing
		 * user provided scan options this time.
		 */
		list< shared_ptr<devices::HardwareDevice> > found;
		if (scan_drv) {
			found = driver_scan(scan_drv, scan_opts);
			if (!found.empty())
				user_spec_device_ = found.front();
		}
	}
	progress->setValue(entry_num++);
}

const shared_ptr<sigrok::Context>& DeviceManager::context() const
{
	return context_;
}

shared_ptr<Context> DeviceManager::context()
{
	return context_;
}

const list< shared_ptr<devices::HardwareDevice> >&
DeviceManager::devices() const
{
	return devices_;
}

/**
 * Get the device that was detected with user provided scan options.
 */
shared_ptr<devices::HardwareDevice>
DeviceManager::user_spec_device() const
{
	return user_spec_device_;
}

/**
 * Convert generic options to data types that are specific to Driver::scan().
 *
 * @param[in] user_spec Vector of tokenized words, string format.
 * @param[in] driver_opts Driver's scan options, result of Driver::scan_options().
 *
 * @return Map of options suitable for Driver::scan().
 */
map<const ConfigKey *, Glib::VariantBase>
DeviceManager::drive_scan_options(vector<string> user_spec,
	set<const ConfigKey *> driver_opts)
{
	map<const ConfigKey *, Glib::VariantBase> result;

	for (auto& entry : user_spec) {
		/*
		 * Split key=value specs. Accept entries without separator
		 * (for simplified boolean specifications).
		 */
		string key, val;
		size_t pos = entry.find("=");
		if (pos == std::string::npos) {
			key = entry;
			val = "";
		} else {
			key = entry.substr(0, pos);
			val = entry.substr(pos + 1);
		}

		/*
		 * Skip user specifications that are not a member of the
		 * driver's set of supported options. Have the text format
		 * input spec converted to the required driver specific type.
		 */
		const ConfigKey *cfg;
		try {
			cfg = ConfigKey::get_by_identifier(key);
			if (!cfg)
				continue;
			if (driver_opts.find(cfg) == driver_opts.end())
				continue;
		} catch (...) {
			continue;
		}
		result[cfg] = cfg->parse_string(val);
	}

	return result;
}

bool DeviceManager::driver_supported(shared_ptr<Driver> driver) const
{
	/*
	 * We currently only support devices that can deliver samples at
	 * a fixed samplerate (i.e. oscilloscopes and logic analysers).
	 *
	 * @todo Add support for non-monotonic devices (DMMs, sensors, etc).
	 */
	const auto keys = driver->config_keys();

	return keys.count(ConfigKey::LOGIC_ANALYZER) | keys.count(ConfigKey::OSCILLOSCOPE);
}

list< shared_ptr<devices::HardwareDevice> >
DeviceManager::driver_scan(
	shared_ptr<Driver> driver, map<const ConfigKey *, VariantBase> drvopts)
{
	list< shared_ptr<devices::HardwareDevice> > driver_devices;

	assert(driver);

	if (!driver_supported(driver))
		return driver_devices;

	// Remove any device instances from this driver from the device
	// list. They will not be valid after the scan.
	devices_.remove_if([&](shared_ptr<devices::HardwareDevice> device) {
		return device->hardware_device()->driver() == driver; });

	try {
		// Do the scan
		auto devices = driver->scan(drvopts);

		// Add the scanned devices to the main list, set display names and sort.
		for (shared_ptr<sigrok::HardwareDevice>& device : devices) {
			const shared_ptr<devices::HardwareDevice> d(
				new devices::HardwareDevice(context_, device));
			driver_devices.push_back(d);
		}

		devices_.insert(devices_.end(), driver_devices.begin(),
			driver_devices.end());
		devices_.sort(bind(&DeviceManager::compare_devices, this, _1, _2));
		driver_devices.sort(bind(
			&DeviceManager::compare_devices, this, _1, _2));

	} catch (const sigrok::Error &e) {
		qWarning() << QApplication::tr("Error when scanning device driver '%1': %2").
			arg(QString::fromStdString(driver->name()), e.what());
	}

	return driver_devices;
}

const map<string, string> DeviceManager::get_device_info(
	shared_ptr<devices::Device> device)
{
	map<string, string> result;

	assert(device);

	const shared_ptr<sigrok::Device> sr_dev = device->device();
	if (sr_dev->vendor().length() > 0)
		result["vendor"] = sr_dev->vendor();
	if (sr_dev->model().length() > 0)
		result["model"] = sr_dev->model();
	if (sr_dev->version().length() > 0)
		result["version"] = sr_dev->version();
	if (sr_dev->serial_number().length() > 0)
		result["serial_num"] = sr_dev->serial_number();
	if (sr_dev->connection_id().length() > 0)
		result["connection_id"] = sr_dev->connection_id();

	return result;
}

const shared_ptr<devices::HardwareDevice> DeviceManager::find_device_from_info(
	const map<string, string> search_info)
{
	shared_ptr<devices::HardwareDevice> last_resort_dev;
	map<string, string> dev_info;

	for (shared_ptr<devices::HardwareDevice> dev : devices_) {
		assert(dev);
		dev_info = get_device_info(dev);

		// If present, vendor and model always have to match.
		if (dev_info.count("vendor") > 0 && search_info.count("vendor") > 0)
			if (dev_info.at("vendor") != search_info.at("vendor"))
				continue;

		if (dev_info.count("model") > 0 && search_info.count("model") > 0)
			if (dev_info.at("model") != search_info.at("model"))
				continue;

		// Most unique match: vendor/model/serial_num (but don't match a S/N of 0)
		if ((dev_info.count("serial_num") > 0) && (dev_info.at("serial_num") != "0")
				&& search_info.count("serial_num") > 0)
			if (dev_info.at("serial_num") == search_info.at("serial_num") &&
					dev_info.at("serial_num") != "0")
				return dev;

		// Second best match: vendor/model/connection_id
		if (dev_info.count("connection_id") > 0 &&
			search_info.count("connection_id") > 0)
			if (dev_info.at("connection_id") == search_info.at("connection_id"))
				return dev;

		// Last resort: vendor/model/version
		if (dev_info.count("version") > 0 &&
			search_info.count("version") > 0)
			if (dev_info.at("version") == search_info.at("version") &&
					dev_info.at("version") != "0")
				return dev;

		// For this device, we merely have a vendor/model match.
		last_resort_dev = dev;
	}

	// If there wasn't even a vendor/model/version match, we end up here.
	// This is usually the case for devices with only vendor/model data.
	// The selected device may be wrong with multiple such devices attached
	// but it is the best we can do at this point. After all, there may be
	// only one such device and we do want to select it in this case.
	return last_resort_dev;
}

bool DeviceManager::compare_devices(shared_ptr<devices::Device> a,
	shared_ptr<devices::Device> b)
{
	assert(a);
	assert(b);
	return a->display_name(*this).compare(b->display_name(*this)) < 0;
}

} // namespace pv
Commit	Line	Data
107ca6d3 JH	1	/*
	2	* This file is part of the PulseView project.
	3	*
	4	* Copyright (C) 2013 Joel Holdsworth <joel@airwebreathe.org.uk>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
efdec55a	17	* along with this program; if not, see <http://www.gnu.org/licenses/>.
107ca6d3 JH	18	*/
107ca6d3 JH	19
2acdb232	20	#include "devicemanager.hpp"
f65cd27b	21	#include "session.hpp"
107ca6d3 JH	22
107ca6d3 JH	23	#include <cassert>
3084ed4b	24	#include <functional>
bc9177b3	25	#include <memory>
e8d00928	26	#include <sstream>
aca9aa83	27	#include <stdexcept>
107ca6d3 JH	28	#include <string>
107ca6d3 JH	29
fe3a1c21	30	#include <libsigrokcxx/libsigrokcxx.hpp>
107ca6d3	31
bc9177b3	32	#include <QApplication>
528a195c	33	#include <QDebug>
bc9177b3 SA	34	#include <QObject>
	35	#include <QProgressDialog>
	36
e8d00928 ML	37	#include <boost/filesystem.hpp>
e8d00928 ML	38
da30ecb7	39	#include <pv/devices/hardwaredevice.hpp>
58d8e4c6	40	#include <pv/util.hpp>
da30ecb7	41
3084ed4b	42	using std::bind;
819f4c25 JH	43	using std::list;
819f4c25 JH	44	using std::map;
e71eb81c JH	45	using std::placeholders::_1;
e71eb81c JH	46	using std::placeholders::_2;
f9abf97e	47	using std::shared_ptr;
819f4c25	48	using std::string;
bc9177b3	49	using std::unique_ptr;
58d8e4c6	50	using std::vector;
e8d00928 ML	51
	52	using Glib::VariantBase;
	53
	54	using sigrok::ConfigKey;
	55	using sigrok::Context;
	56	using sigrok::Driver;
107ca6d3 JH	57
	58	namespace pv {
	59
1d6e35dc GS	60	DeviceManager::DeviceManager(shared_ptr<Context> context,
1d6e35dc GS	61	std::string driver, bool do_scan) :
8dbbc7f0	62	context_(context)
107ca6d3	63	{
bc9177b3	64	unique_ptr<QProgressDialog> progress(new QProgressDialog("",
58d8e4c6	65	QObject::tr("Cancel"), 0, context->drivers().size() + 1));
bc9177b3 SA	66	progress->setWindowModality(Qt::WindowModal);
	67	progress->setMinimumDuration(1); // To show the dialog immediately
	68
	69	int entry_num = 1;
	70
58d8e4c6 GS	71	/*
	72	* Check the presence of an optional user spec for device scans.
	73	* Determine the driver name and options (in generic format) when
	74	* applicable.
	75	*/
	76	std::string user_name;
	77	vector<std::string> user_opts;
	78	if (!driver.empty()) {
	79	user_opts = pv::util::split_string(driver, ":");
	80	user_name = user_opts.front();
	81	user_opts.erase(user_opts.begin());
	82	}
	83
	84	/*
	85	* Scan for devices. No specific options apply here, this is
	86	* best effort auto detection.
	87	*/
f4ab4b5c	88	for (auto& entry : context->drivers()) {
1d6e35dc GS	89	if (!do_scan)
1d6e35dc GS	90	break;
8d054b91 SA	91
	92	// Skip drivers we won't scan anyway
	93	if (!driver_supported(entry.second))
	94	continue;
	95
0ea2cfc5	96	progress->setLabelText(QObject::tr("Scanning for devices that driver %1 can access...")
bc9177b3 SA	97	.arg(QString::fromStdString(entry.first)));
bc9177b3 SA	98
58d8e4c6 GS	99	if (entry.first == user_name)
58d8e4c6 GS	100	continue;
941e22a6	101	driver_scan(entry.second, map<const ConfigKey *, VariantBase>());
bc9177b3 SA	102
	103	progress->setValue(entry_num++);
	104	QApplication::processEvents();
	105	if (progress->wasCanceled())
	106	break;
	107	}
58d8e4c6 GS	108
	109	/*
	110	* Optionally run another scan with potentially more specific
	111	* options when requested by the user. This is motivated by
	112	* several different uses: It can find devices that are not
	113	* covered by the above auto detection (UART, TCP). It can
	114	* prefer one out of multiple found devices, and have this
	115	* device pre-selected for new sessions upon user's request.
	116	*/
	117	user_spec_device_.reset();
	118	if (!driver.empty()) {
	119	shared_ptr<sigrok::Driver> scan_drv;
	120	map<const ConfigKey *, VariantBase> scan_opts;
	121
	122	/*
	123	* Lookup the device driver name.
	124	*/
	125	map<string, shared_ptr<Driver>> drivers = context->drivers();
	126	auto entry = drivers.find(user_name);
	127	scan_drv = (entry != drivers.end()) ? entry->second : nullptr;
	128
	129	/*
	130	* Convert generic string representation of options
	131	* to the driver specific data types.
	132	*/
	133	if (scan_drv && !user_opts.empty()) {
	134	auto drv_opts = scan_drv->scan_options();
	135	scan_opts = drive_scan_options(user_opts, drv_opts);
	136	}
	137
	138	/*
	139	* Run another scan for the specified driver, passing
	140	* user provided scan options this time.
	141	*/
	142	list< shared_ptr<devices::HardwareDevice> > found;
	143	if (scan_drv) {
	144	found = driver_scan(scan_drv, scan_opts);
	145	if (!found.empty())
	146	user_spec_device_ = found.front();
	147	}
	148	}
	149	progress->setValue(entry_num++);
107ca6d3 JH	150	}
107ca6d3 JH	151
6f925ba9	152	const shared_ptr<sigrok::Context>& DeviceManager::context() const
72d85f36 JH	153	{
	154	return context_;
	155	}
	156
e8d00928 ML	157	shared_ptr<Context> DeviceManager::context()
e8d00928 ML	158	{
8dbbc7f0	159	return context_;
e8d00928 ML	160	}
e8d00928 ML	161
da30ecb7 JH	162	const list< shared_ptr<devices::HardwareDevice> >&
da30ecb7 JH	163	DeviceManager::devices() const
107ca6d3	164	{
8dbbc7f0	165	return devices_;
107ca6d3 JH	166	}
107ca6d3 JH	167
58d8e4c6 GS	168	/**
	169	* Get the device that was detected with user provided scan options.
	170	*/
	171	shared_ptr<devices::HardwareDevice>
	172	DeviceManager::user_spec_device() const
	173	{
	174	return user_spec_device_;
	175	}
	176
	177	/**
	178	* Convert generic options to data types that are specific to Driver::scan().
	179	*
3083cda8 UH	180	* @param[in] user_spec Vector of tokenized words, string format.
3083cda8 UH	181	* @param[in] driver_opts Driver's scan options, result of Driver::scan_options().
58d8e4c6	182	*
3083cda8	183	* @return Map of options suitable for Driver::scan().
58d8e4c6 GS	184	*/
	185	map<const ConfigKey *, Glib::VariantBase>
	186	DeviceManager::drive_scan_options(vector<string> user_spec,
	187	set<const ConfigKey *> driver_opts)
	188	{
	189	map<const ConfigKey *, Glib::VariantBase> result;
	190
f4ab4b5c	191	for (auto& entry : user_spec) {
58d8e4c6 GS	192	/*
	193	* Split key=value specs. Accept entries without separator
	194	* (for simplified boolean specifications).
	195	*/
	196	string key, val;
	197	size_t pos = entry.find("=");
	198	if (pos == std::string::npos) {
	199	key = entry;
	200	val = "";
	201	} else {
	202	key = entry.substr(0, pos);
	203	val = entry.substr(pos + 1);
	204	}
	205
	206	/*
	207	* Skip user specifications that are not a member of the
	208	* driver's set of supported options. Have the text format
	209	* input spec converted to the required driver specific type.
	210	*/
	211	const ConfigKey *cfg;
	212	try {
	213	cfg = ConfigKey::get_by_identifier(key);
	214	if (!cfg)
	215	continue;
	216	if (driver_opts.find(cfg) == driver_opts.end())
	217	continue;
	218	} catch (...) {
	219	continue;
	220	}
	221	result[cfg] = cfg->parse_string(val);
	222	}
	223
	224	return result;
	225	}
	226
8d054b91	227	bool DeviceManager::driver_supported(shared_ptr<Driver> driver) const
107ca6d3	228	{
941e22a6 GS	229	/*
	230	* We currently only support devices that can deliver samples at
	231	* a fixed samplerate (i.e. oscilloscopes and logic analysers).
	232	*
	233	* @todo Add support for non-monotonic devices (DMMs, sensors, etc).
	234	*/
	235	const auto keys = driver->config_keys();
8d054b91 SA	236
	237	return keys.count(ConfigKey::LOGIC_ANALYZER) \| keys.count(ConfigKey::OSCILLOSCOPE);
	238	}
	239
	240	list< shared_ptr<devices::HardwareDevice> >
	241	DeviceManager::driver_scan(
	242	shared_ptr<Driver> driver, map<const ConfigKey *, VariantBase> drvopts)
	243	{
	244	list< shared_ptr<devices::HardwareDevice> > driver_devices;
	245
	246	assert(driver);
	247
	248	if (!driver_supported(driver))
941e22a6 GS	249	return driver_devices;
941e22a6 GS	250
107ca6d3 JH	251	// Remove any device instances from this driver from the device
107ca6d3 JH	252	// list. They will not be valid after the scan.
da30ecb7 JH	253	devices_.remove_if([&](shared_ptr<devices::HardwareDevice> device) {
da30ecb7 JH	254	return device->hardware_device()->driver() == driver; });
107ca6d3	255
528a195c SA	256	try {
	257	// Do the scan
	258	auto devices = driver->scan(drvopts);
107ca6d3	259
528a195c SA	260	// Add the scanned devices to the main list, set display names and sort.
	261	for (shared_ptr<sigrok::HardwareDevice>& device : devices) {
	262	const shared_ptr<devices::HardwareDevice> d(
	263	new devices::HardwareDevice(context_, device));
	264	driver_devices.push_back(d);
	265	}
a4cf020a	266
528a195c SA	267	devices_.insert(devices_.end(), driver_devices.begin(),
	268	driver_devices.end());
	269	devices_.sort(bind(&DeviceManager::compare_devices, this, _1, _2));
	270	driver_devices.sort(bind(
	271	&DeviceManager::compare_devices, this, _1, _2));
	272
	273	} catch (const sigrok::Error &e) {
	274	qWarning() << QApplication::tr("Error when scanning device driver '%1': %2").
	275	arg(QString::fromStdString(driver->name()), e.what());
	276	}
107ca6d3 JH	277
	278	return driver_devices;
	279	}
	280
e8d00928	281	const map<string, string> DeviceManager::get_device_info(
da30ecb7	282	shared_ptr<devices::Device> device)
e8d00928 ML	283	{
	284	map<string, string> result;
	285
	286	assert(device);
	287
da30ecb7 JH	288	const shared_ptr<sigrok::Device> sr_dev = device->device();
	289	if (sr_dev->vendor().length() > 0)
	290	result["vendor"] = sr_dev->vendor();
	291	if (sr_dev->model().length() > 0)
	292	result["model"] = sr_dev->model();
	293	if (sr_dev->version().length() > 0)
	294	result["version"] = sr_dev->version();
	295	if (sr_dev->serial_number().length() > 0)
	296	result["serial_num"] = sr_dev->serial_number();
	297	if (sr_dev->connection_id().length() > 0)
	298	result["connection_id"] = sr_dev->connection_id();
e8d00928 ML	299
	300	return result;
	301	}
	302
da30ecb7	303	const shared_ptr<devices::HardwareDevice> DeviceManager::find_device_from_info(
6842b5fc SA	304	const map<string, string> search_info)
6842b5fc SA	305	{
da30ecb7	306	shared_ptr<devices::HardwareDevice> last_resort_dev;
6842b5fc SA	307	map<string, string> dev_info;
6842b5fc SA	308
da30ecb7	309	for (shared_ptr<devices::HardwareDevice> dev : devices_) {
6842b5fc	310	assert(dev);
e8d00928	311	dev_info = get_device_info(dev);
6842b5fc SA	312
	313	// If present, vendor and model always have to match.
	314	if (dev_info.count("vendor") > 0 && search_info.count("vendor") > 0)
2ad82c2e UH	315	if (dev_info.at("vendor") != search_info.at("vendor"))
2ad82c2e UH	316	continue;
6842b5fc SA	317
6842b5fc SA	318	if (dev_info.count("model") > 0 && search_info.count("model") > 0)
2ad82c2e UH	319	if (dev_info.at("model") != search_info.at("model"))
2ad82c2e UH	320	continue;
6842b5fc SA	321
	322	// Most unique match: vendor/model/serial_num (but don't match a S/N of 0)
	323	if ((dev_info.count("serial_num") > 0) && (dev_info.at("serial_num") != "0")
	324	&& search_info.count("serial_num") > 0)
	325	if (dev_info.at("serial_num") == search_info.at("serial_num") &&
	326	dev_info.at("serial_num") != "0")
	327	return dev;
	328
	329	// Second best match: vendor/model/connection_id
	330	if (dev_info.count("connection_id") > 0 &&
	331	search_info.count("connection_id") > 0)
	332	if (dev_info.at("connection_id") == search_info.at("connection_id"))
	333	return dev;
	334
	335	// Last resort: vendor/model/version
	336	if (dev_info.count("version") > 0 &&
	337	search_info.count("version") > 0)
	338	if (dev_info.at("version") == search_info.at("version") &&
	339	dev_info.at("version") != "0")
	340	return dev;
	341
	342	// For this device, we merely have a vendor/model match.
	343	last_resort_dev = dev;
	344	}
	345
	346	// If there wasn't even a vendor/model/version match, we end up here.
	347	// This is usually the case for devices with only vendor/model data.
	348	// The selected device may be wrong with multiple such devices attached
	349	// but it is the best we can do at this point. After all, there may be
	350	// only one such device and we do want to select it in this case.
	351	return last_resort_dev;
	352	}
	353
3084ed4b	354	bool DeviceManager::compare_devices(shared_ptr<devices::Device> a,
2ad82c2e UH	355	shared_ptr<devices::Device> b)
2ad82c2e UH	356	{
19adbc2c JH	357	assert(a);
19adbc2c JH	358	assert(b);
3084ed4b	359	return a->display_name(this).compare(b->display_name(this)) < 0;
107ca6d3 JH	360	}
	361
	362	} // namespace pv