/*
* This file is part of VLCJ.
*
* VLCJ 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 3 of the License, or
* (at your option) any later version.
*
* VLCJ 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 VLCJ. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2009, 2010, 2011, 2012, 2013, 2014 Caprica Software Limited.
*/
package uk.co.caprica.vlcj.discovery;
import uk.co.caprica.vlcj.Info;
import uk.co.caprica.vlcj.binding.LibVlcFactory;
import uk.co.caprica.vlcj.discovery.linux.DefaultLinuxNativeDiscoveryStrategy;
import uk.co.caprica.vlcj.discovery.mac.DefaultMacNativeDiscoveryStrategy;
import uk.co.caprica.vlcj.discovery.windows.DefaultWindowsNativeDiscoveryStrategy;
import uk.co.caprica.vlcj.logger.Logger;
import uk.co.caprica.vlcj.runtime.RuntimeUtil;
import com.sun.jna.NativeLibrary;
/**
* A component that uses discovery strategies to locate the libvlc native
* libraries and register their location with the JNA run-time.
* <p>
* To try and automatically locate the libvlc native libraries with the default
* strategies, at the start of application code simply do:
* <pre>
* new NativeDiscovery().discover();
* </pre>
* Custom discovery strategy implementations may of course be used instead of or
* in addition to the defaults.
* <p>
* An alternate approach is to configure a {@link LibVlcFactory} via
* {@link LibVlcFactory#discovery(NativeDiscovery)}.
* <p>
* <em>Discovery should only be executed once, and this should be done at the
* start of the application - before referencing any other vlcj classes.</em>
*/
public class NativeDiscovery {
/**
* Application information.
*/
static {
Info.getInstance();
}
/**
* Name of the system property that JNA uses to find native libraries.
*/
private static final String JNA_SYSTEM_PROPERTY_NAME = "jna.library.path";
/**
* Strategy implementations.
*/
private final NativeDiscoveryStrategy[] discoveryStrategies;
/**
* Create a discovery component with bespoke strategies.
*
* @param discoveryStrategies strategy implementations
*/
public NativeDiscovery(NativeDiscoveryStrategy... discoveryStrategies) {
this.discoveryStrategies = discoveryStrategies;
}
/**
* Create a discovery component with the default platform strategies.
*/
public NativeDiscovery() {
this(
new DefaultLinuxNativeDiscoveryStrategy(),
new DefaultWindowsNativeDiscoveryStrategy(),
new DefaultMacNativeDiscoveryStrategy()
);
}
/**
* Attempt to discover the location of the libvlc native libraries.
* <p>
* If the native libraries were found, the directory reported to be containing
* those libraries is explicitly added to the JNA native library search path.
*
* @return <code>true</code> if the native libraries were found; otherwise <code>false</code>
*/
public final boolean discover() {
Logger.debug("discover()");
// Check if the JNA system property is set - if so, this trumps discovery
String jnaLibraryPath = System.getProperty(JNA_SYSTEM_PROPERTY_NAME);
Logger.debug("jnaLibraryPath={}", jnaLibraryPath);
// JNA system property not set...
if(jnaLibraryPath == null) {
// Try each strategy in turn...
for(NativeDiscoveryStrategy discoveryStrategy : discoveryStrategies) {
Logger.debug("discoveryStrategy={}", discoveryStrategy);
// Is this strategy supported for this run-time?
boolean supported = discoveryStrategy.supported();
Logger.debug("supported={}", supported);
if(supported) {
String path = discoveryStrategy.discover();
Logger.debug("path={}", path);
if(path != null) {
Logger.info("Discovery found libvlc at '{}'", path);
// Register the discovered library path with JNA
NativeLibrary.addSearchPath(RuntimeUtil.getLibVlcLibraryName(), path);
return true;
}
}
}
Logger.warn("Discovery did not find libvlc");
}
else {
Logger.info("Skipped discovery as system property '{}' already set to '{}'", JNA_SYSTEM_PROPERTY_NAME, jnaLibraryPath);
}
return false;
}
}