Method SelectDriverImpl

src/driver.cpp:110–203

* Find the requested driver and return its class. * @param name the driver to select. * @param type the type of driver to select * @post Sets the driver so GetCurrentDriver() returns it too. * @return True upon success, otherwise false. */

 * @return True upon success, otherwise false.
 */
bool DriverFactoryBase::SelectDriverImpl(const std::string &name, Driver::Type type)
{
	if (GetDrivers().empty()) return false;

	if (name.empty()) {
		/* Probe for this driver, but do not fall back to dedicated/null! */
		for (int priority = 10; priority > 0; priority--) {
			for (auto &it : GetDrivers()) {
				DriverFactoryBase *d = it.second;

				/* Check driver type */
				if (d->type != type) continue;
				if (d->priority != priority) continue;

				if (type == Driver::DT_VIDEO && !_video_hw_accel && d->UsesHardwareAcceleration()) continue;

				if (type == Driver::DT_VIDEO && _video_hw_accel && d->UsesHardwareAcceleration()) {
					/* Check if we have already tried this driver in last run.
					 * If it is here, it most likely means we crashed. So skip
					 * hardware acceleration. */
					auto filename = FioFindFullPath(BASE_DIR, HWACCELERATION_TEST_FILE);
					if (!filename.empty()) {
						FioRemove(filename);

						Debug(driver, 1, "Probing {} driver '{}' skipped due to earlier crash", GetDriverTypeName(type), d->name);

						_video_hw_accel = false;
						ErrorMessageData msg(GetEncodedString(STR_VIDEO_DRIVER_ERROR), GetEncodedString(STR_VIDEO_DRIVER_ERROR_HARDWARE_ACCELERATION_CRASH), true);
						ScheduleErrorMessage(std::move(msg));
						continue;
					}

					/* Write empty file to note we are attempting hardware acceleration. */
					FioFOpenFile(HWACCELERATION_TEST_FILE, "w", BASE_DIR);
				}

				/* Keep old driver in case we need to switch back, or may still need to process an OS callback. */
				auto oldd = std::move(GetActiveDriver(type));
				auto newd = d->CreateInstance();

				auto err = newd->Start({});
				if (!err) {
					Debug(driver, 1, "Successfully probed {} driver '{}'", GetDriverTypeName(type), d->name);
					GetActiveDriver(type) = std::move(newd);
					return true;
				}

				GetActiveDriver(type) = std::move(oldd);
				Debug(driver, 1, "Probing {} driver '{}' failed with error: {}", GetDriverTypeName(type), d->name, *err);

				if (type == Driver::DT_VIDEO && _video_hw_accel && d->UsesHardwareAcceleration()) {
					_video_hw_accel = false;
					ErrorMessageData msg(GetEncodedString(STR_VIDEO_DRIVER_ERROR), GetEncodedString(STR_VIDEO_DRIVER_ERROR_NO_HARDWARE_ACCELERATION), true);
					ScheduleErrorMessage(std::move(msg));
				}
			}
		}
		UserError("Couldn't find any suitable {} driver", GetDriverTypeName(type));