VolumeControl/driver/VC_PlugIn.cpp

// This file is part of Background Music.
//
// Background Music 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.
//
// Background Music 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 Background Music. If not, see <http://www.gnu.org/licenses/>.

//
//  VC_PlugIn.cpp
//  VCDriver
//
//  Copyright © 2016, 2017 Kyle Neideck
//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
//
//  Based largely on SA_PlugIn.cpp from Apple's SimpleAudioDriver Plug-In sample code.
//  https://developer.apple.com/library/mac/samplecode/AudioDriverExamples
//

//	Self Include
#include "VC_PlugIn.h"

//  Local Includes
#include "VC_Device.h"

//  PublicUtility Includes
#include "CAException.h"
#include "CADebugMacros.h"
#include "CAPropertyAddress.h"
#include "CADispatchQueue.h"


#pragma mark Construction/Destruction

pthread_once_t				VC_PlugIn::sStaticInitializer = PTHREAD_ONCE_INIT;
VC_PlugIn*					VC_PlugIn::sInstance = NULL;
AudioServerPlugInHostRef	VC_PlugIn::sHost = NULL;

VC_PlugIn& VC_PlugIn::GetInstance()
{
    pthread_once(&sStaticInitializer, StaticInitializer);
    return *sInstance;
}

void	VC_PlugIn::StaticInitializer()
{
    try
    {
        sInstance = new VC_PlugIn;
        sInstance->Activate();
    }
    catch(...)
    {
        DebugMsg("VC_PlugIn::StaticInitializer: failed to create the plug-in");
        delete sInstance;
        sInstance = NULL;
    }
}

VC_PlugIn::VC_PlugIn()
:
	VC_Object(kAudioObjectPlugInObject, kAudioPlugInClassID, kAudioObjectClassID, 0),
	mMutex("VC_PlugIn")
{
}

VC_PlugIn::~VC_PlugIn()
{
}

void	VC_PlugIn::Deactivate()
{
	CAMutex::Locker theLocker(mMutex);
	VC_Object::Deactivate();
    // TODO:
	//_RemoveAllDevices();
}

#pragma mark Property Operations

bool	VC_PlugIn::HasProperty(AudioObjectID inObjectID, pid_t inClientPID, const AudioObjectPropertyAddress& inAddress) const
{
	bool theAnswer = false;
	switch(inAddress.mSelector)
	{
		case kAudioObjectPropertyManufacturer:
		case kAudioPlugInPropertyDeviceList:
		case kAudioPlugInPropertyTranslateUIDToDevice:
        case kAudioPlugInPropertyResourceBundle:
			theAnswer = true;
			break;
		
		default:
			theAnswer = VC_Object::HasProperty(inObjectID, inClientPID, inAddress);
	};
	return theAnswer;
}

bool	VC_PlugIn::IsPropertySettable(AudioObjectID inObjectID, pid_t inClientPID, const AudioObjectPropertyAddress& inAddress) const
{
	bool theAnswer = false;
	switch(inAddress.mSelector)
	{
		case kAudioObjectPropertyManufacturer:
		case kAudioPlugInPropertyDeviceList:
		case kAudioPlugInPropertyTranslateUIDToDevice:
        case kAudioPlugInPropertyResourceBundle:
			theAnswer = false;
			break;
		
		default:
			theAnswer = VC_Object::IsPropertySettable(inObjectID, inClientPID, inAddress);
	};
	return theAnswer;
}

UInt32	VC_PlugIn::GetPropertyDataSize(AudioObjectID inObjectID, pid_t inClientPID, const AudioObjectPropertyAddress& inAddress, UInt32 inQualifierDataSize, const void* inQualifierData) const
{
	UInt32 theAnswer = 0;
	switch(inAddress.mSelector)
	{
		case kAudioObjectPropertyManufacturer:
			theAnswer = sizeof(CFStringRef);
			break;
			
		case kAudioObjectPropertyOwnedObjects:
		case kAudioPlugInPropertyDeviceList:
            theAnswer = sizeof(AudioObjectID);
			break;
			
		case kAudioPlugInPropertyTranslateUIDToDevice:
			theAnswer = sizeof(AudioObjectID);
			break;
			
		case kAudioPlugInPropertyResourceBundle:
			theAnswer = sizeof(CFStringRef);
			break;

		default:
			theAnswer = VC_Object::GetPropertyDataSize(inObjectID, inClientPID, inAddress, inQualifierDataSize, inQualifierData);
	};
	return theAnswer;
}

void	VC_PlugIn::GetPropertyData(AudioObjectID inObjectID, pid_t inClientPID, const AudioObjectPropertyAddress& inAddress, UInt32 inQualifierDataSize, const void* inQualifierData, UInt32 inDataSize, UInt32& outDataSize, void* outData) const
{
	switch(inAddress.mSelector)
	{
		case kAudioObjectPropertyManufacturer:
			//	This is the human readable name of the maker of the plug-in.
			ThrowIf(inDataSize < sizeof(CFStringRef), CAException(kAudioHardwareBadPropertySizeError), "VC_PlugIn::GetPropertyData: not enough space for the return value of kAudioObjectPropertyManufacturer");
			*reinterpret_cast<CFStringRef*>(outData) = CFSTR("VolumeControl");
			outDataSize = sizeof(CFStringRef);
			break;
			
		case kAudioObjectPropertyOwnedObjects:
            // Fall through because this plug-in object only owns the device.
		case kAudioPlugInPropertyDeviceList:
            {
    			AudioObjectID* theReturnedDeviceList = reinterpret_cast<AudioObjectID*>(outData);
                if(inDataSize >= sizeof(AudioObjectID))
                {
                    theReturnedDeviceList[0] = kObjectID_Device;
                    outDataSize = sizeof(AudioObjectID);
                }
                else
                {
                    outDataSize = 0;
                }
            }
			break;
			
		case kAudioPlugInPropertyTranslateUIDToDevice:
            {
                //	This property translates the UID passed in the qualifier as a CFString into the
                //	AudioObjectID for the device the UID refers to or kAudioObjectUnknown if no device
                //	has the UID.
                ThrowIf(inQualifierDataSize < sizeof(CFStringRef), CAException(kAudioHardwareBadPropertySizeError), "VC_PlugIn::GetPropertyData: the qualifier size is too small for kAudioPlugInPropertyTranslateUIDToDevice");
                ThrowIf(inDataSize < sizeof(AudioObjectID), CAException(kAudioHardwareBadPropertySizeError), "VC_PlugIn::GetPropertyData: not enough space for the return value of kAudioPlugInPropertyTranslateUIDToDevice");

                CFStringRef theUID = *reinterpret_cast<const CFStringRef*>(inQualifierData);
                AudioObjectID* outID = reinterpret_cast<AudioObjectID*>(outData);

                if(CFEqual(theUID, VC_Device::GetInstance().CopyDeviceUID()))
                {
                    DebugMsg("VC_PlugIn::GetPropertyData: Returning VCDevice for "
                             "kAudioPlugInPropertyTranslateUIDToDevice");
                    *outID = kObjectID_Device;
                }
                else
                {
                    LogWarning("VC_PlugIn::GetPropertyData: Returning kAudioObjectUnknown for "
                               "kAudioPlugInPropertyTranslateUIDToDevice");
                    *outID = kAudioObjectUnknown;
                }

                outDataSize = sizeof(AudioObjectID);
            }
			break;
			
		case kAudioPlugInPropertyResourceBundle:
			//	The resource bundle is a path relative to the path of the plug-in's bundle.
			//	To specify that the plug-in bundle itself should be used, we just return the
			//	empty string.
			ThrowIf(inDataSize < sizeof(AudioObjectID), CAException(kAudioHardwareBadPropertySizeError), "VC_GetPlugInPropertyData: not enough space for the return value of kAudioPlugInPropertyResourceBundle");
			*reinterpret_cast<CFStringRef*>(outData) = CFSTR("");
			outDataSize = sizeof(CFStringRef);
			break;

		default:
			VC_Object::GetPropertyData(inObjectID, inClientPID, inAddress, inQualifierDataSize, inQualifierData, inDataSize, outDataSize, outData);
			break;
	};
}

void	VC_PlugIn::SetPropertyData(AudioObjectID inObjectID, pid_t inClientPID, const AudioObjectPropertyAddress& inAddress, UInt32 inQualifierDataSize, const void* inQualifierData, UInt32 inDataSize, const void* inData)
{
	switch(inAddress.mSelector)
	{
		default:
			VC_Object::SetPropertyData(inObjectID, inClientPID, inAddress, inQualifierDataSize, inQualifierData, inDataSize, inData);
			break;
	};
}