/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.driver.video;
import java.util.Stack;
import javax.naming.NameNotFoundException;
import org.apache.log4j.Logger;
import org.jnode.driver.Device;
import org.jnode.driver.DeviceAlreadyRegisteredException;
import org.jnode.driver.DeviceManager;
import org.jnode.driver.Driver;
import org.jnode.driver.DriverException;
import org.jnode.naming.InitialNaming;
/**
* @author epr
*/
public abstract class AbstractFrameBufferDriver extends Driver implements FrameBufferAPI {
/** My logger */
private static final Logger log = Logger.getLogger(AbstractFrameBufferDriver.class);
/** Device name prefix of framebuffer devices */
public static final String FB_DEVICE_PREFIX = "fb";
private Stack<FrameBufferAPIOwner> owners = new Stack<FrameBufferAPIOwner>();
/**
* @see org.jnode.driver.Driver#startDevice()
*/
protected void startDevice() throws DriverException {
final Device device = getDevice();
try {
final DeviceManager dm = InitialNaming.lookup(DeviceManager.NAME);
dm.rename(device, getDevicePrefix() + "-" + device.getId(), false);
} catch (DeviceAlreadyRegisteredException ex) {
log.error("Cannot rename device", ex);
} catch (NameNotFoundException ex) {
throw new DriverException("Cannot find DeviceManager", ex);
}
device.registerAPI(FrameBufferAPI.class, this);
}
/**
* Request to be the owner of the underlying FrameBuffer device.
* The old owner (if any) will receive a request to stop using the underlying FrameBuffer device.
*
* @param owner
*/
@Override
public final void requestOwnership(FrameBufferAPIOwner owner) {
FrameBufferAPIOwner oldOwner = null;
if (!owners.isEmpty()) {
oldOwner = owners.peek();
if (oldOwner == owner) {
// already the owner, simply skip
// (avoid infinite loop with requestOwnership & releaseOwnership)
return;
}
}
owners.push(owner);
if (oldOwner != null) {
oldOwner.ownershipLost();
}
// the owner doesn't need to be notified since the caller knows it
// ...
}
/**
* Request to be the owner of the underlying FrameBuffer device.
* The old owner (if any) will receive a request to stop using the underlying FrameBuffer device.
*
* @param owner
*/
@Override
public final void releaseOwnership(FrameBufferAPIOwner owner) {
FrameBufferAPIOwner newOwner = null;
if (!owners.isEmpty()) {
if (owners.peek().equals(owner)) {
// the owner doesn't need to be notified since the caller knows it
// simply remove it from the stack
owners.pop();
if (!owners.isEmpty()) {
newOwner = owners.peek();
}
} else {
throw new IllegalArgumentException("parameter is not the current owner");
}
}
// notify new owner (if any) that he gained ownership
if (newOwner != null) {
newOwner.ownershipGained();
}
}
/**
* @see org.jnode.driver.Driver#stopDevice()
*/
protected void stopDevice() throws DriverException {
final Device dev = getDevice();
dev.unregisterAPI(FrameBufferAPI.class);
}
/**
* Gets the prefix for the device name
*
* @see #FB_DEVICE_PREFIX
*/
protected String getDevicePrefix() {
return FB_DEVICE_PREFIX;
}
}