Tibor17 commented on a change in pull request #65:
URL: https://github.com/apache/maven-resolver/pull/65#discussion_r456789040
##########
File path:
maven-resolver-impl/src/main/java/org/eclipse/aether/internal/impl/DefaultSyncContextFactory.java
##########
@@ -28,31 +30,59 @@
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.impl.SyncContextFactory;
import org.eclipse.aether.metadata.Metadata;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.inject.Singleton;
/**
- * A factory to create synchronization contexts. This default implementation
actually does not provide any real
- * synchronization but merely completes the repository system.
+ * A factory to create synchronization contexts. This default implementation
uses fair global locking
+ * based on {@link ReentrantReadWriteLock}. Explicit artifacts and metadata
passed are ignored.
*/
@Named
+@Singleton
public class DefaultSyncContextFactory
implements SyncContextFactory
{
+ private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(
true );
public SyncContext newInstance( RepositorySystemSession session, boolean
shared )
{
- return new DefaultSyncContext();
+ return new DefaultSyncContext( shared ? lock.readLock() :
lock.writeLock(), shared );
}
static class DefaultSyncContext
implements SyncContext
{
+ private static final Logger LOGGER = LoggerFactory.getLogger(
DefaultSyncContext.class );
+
+ private final Lock lock;
+ private final boolean shared;
+ private int lockHoldCount;
+
+ DefaultSyncContext( Lock lock, boolean shared )
+ {
+ this.lock = lock;
+ this.shared = shared;
+ }
public void acquire( Collection<? extends Artifact> artifact,
Collection<? extends Metadata> metadata )
{
+ LOGGER.trace( "Acquiring global {} lock (currently held: {})",
+ shared ? "read" : "write", lockHoldCount );
+ lock.lock();
Review comment:
This is really dangerous and antipattern because you here can call
lock/unlock in different threads since you have two methods. See the Javadoc.
It says to use try-finally. And it is because the method contaxt is always
called in one thread and that's the point of locking that you lock and unlock
your thread. But unparking another thread is dangerous.
Maybe change the API or the abstraction in this class but do not use these
principles.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
