C++ Mixer::isValid方法代码示例

/**
 * Scan for Mixers in the System. This is the method that implicitely fills the
 * list of Mixer's, which is accesible via the static Mixer::mixer() method.
 * @par mixers The list where to add the found Mixers. This parameter is superfluous
 *             nowadays, as it is now really trivial to get it - just call the static
 *             Mixer::mixer() method.
 * @par multiDriverMode Whether the Mixer scan should try more all backendends.
 *          'true' means to scan all backends. 'false' means: After scanning the
 *          current backend the next backend is only scanned if no Mixers were found yet.
 */
void MixerToolBox::initMixer(QPtrList<Mixer> &mixers, bool multiDriverMode, QString& ref_hwInfoString)
{
   //kdDebug(67100) << "IN MixerToolBox::initMixer()"<<endl;

    // Find all mixers and initalize them
    QMap<QString,int> mixerNums;
    int drvNum = Mixer::numDrivers();

    int driverWithMixer = -1;
    bool multipleDriversActive = false;

    QString driverInfo = "";
    QString driverInfoUsed = "";

    for( int drv1=0; drv1<drvNum; drv1++ )
    {
      QString driverName = Mixer::driverName(drv1);
      if ( driverInfo.length() > 0 )
	driverInfo += " + ";
      driverInfo += driverName;
    }
	/* Run a loop over all drivers. The loop will terminate after the first driver which
	   has mixers. And here is the reason:
	   - If you run ALSA with ALSA-OSS-Emulation enabled, mixers will show up twice: once
	     as native ALSA mixer, once as OSS mixer (emulated by ALSA). This is bad and WILL
	     confuse users. So it is a design decision that we can compile in multiple drivers
	     but we can run only one driver.
	   - For special usage scenarios, people will still want to run both drivers at the
	     same time. We allow them to hack their Config-File, where they can enable a
	     multi-driver mode.
	   - Another remark: For KMix3.0 or so, we should allow multiple-driver, for allowing
	     addition of special-use drivers, e.g. an Jack-Mixer-Backend, or a CD-Rom volume Backend.
	 */

    bool autodetectionFinished = false;
    for( int drv=0; drv<drvNum; drv++ )
    {
	  QString driverName = Mixer::driverName(drv);

	  if ( autodetectionFinished ) {
		// sane exit from loop
		break;
	    }

	    bool drvInfoAppended = false;
	    // The "19" below is just a "silly" number:
	    // (Old: The loop will break as soon as an error is detected - e.g. on 3rd loop when 2 soundcards are installed)
	    // New: We don't try be that clever anymore. We now blindly scan 20 cards, as the clever
	    // approach doesn't work for the one or other user.
	    int devNumMax = 19;
	    for( int dev=0; dev<=devNumMax; dev++ )
	    {
		Mixer *mixer = new Mixer( drv, dev );
		if ( mixer->isValid() ) {
			mixer->open();
			mixers.append( mixer );
			// Count mixer nums for every mixer name to identify mixers with equal names.
			// This is for creating persistent (reusable) primary keys, which can safely
			// be referenced (especially for config file access, so it is meant to be persistent!).
			mixerNums[mixer->mixerName()]++;
			// Create a useful PK
			/* As we use "::" and ":" as separators, the parts %1,%2 and %3 may not
			 * contain it.
			 * %1, the driver name is from the KMix backends, it does not contain colons.
			 * %2, the mixer name, is typically coming from an OS driver. It could contain colons.
			 * %3, the mixer number, is a number: it does not contain colons.
			 */
			QString mixerName = mixer->mixerName();
			mixerName.replace(":","_");
			QString primaryKeyOfMixer = QString("%1::%2:%3")
			    .arg(driverName)
			    .arg(mixerName)
			    .arg(mixerNums[mixer->mixerName()]);
			// The following 3 replaces are for not messing up the config file
			primaryKeyOfMixer.replace("]","_");
			primaryKeyOfMixer.replace("[","_"); // not strictly neccesary, but lets play safe
			primaryKeyOfMixer.replace(" ","_");
			primaryKeyOfMixer.replace("=","_");
			
			mixer->setID(primaryKeyOfMixer);

		} // valid
		else
		{
			delete mixer;
			mixer = 0;
		} // invalid

		/* Lets decide if we the autoprobing shall continue: */
		if ( multiDriverMode ) {
//.........这里部分代码省略.........