ContextManager.java

package jetbrains.mps.debugger.java.runtime.engine.events;

/*Generated by MPS */

import org.apache.log4j.Logger;
import org.apache.log4j.LogManager;
import java.util.List;
import jetbrains.mps.internal.collections.runtime.ListSequence;
import java.util.ArrayList;
import jetbrains.mps.baseLanguage.closures.runtime._FunctionTypes;
import com.sun.jdi.ObjectCollectedException;
import com.sun.jdi.InternalException;
import com.sun.jdi.request.EventRequest;
import org.apache.log4j.Level;
import org.jetbrains.annotations.Nullable;
import com.sun.jdi.ThreadReference;
import jetbrains.mps.internal.collections.runtime.IWhereFilter;

public class ContextManager {
  private static final Logger LOG = LogManager.getLogger(ContextManager.class);
  private final List<EventContext> mySuspendedContexts = ListSequence.fromList(new ArrayList<EventContext>());
  private UserContext myUserContext;
  public ContextManager() {
  }
  /*package*/ synchronized boolean votePause(EventContext context) {
    context.vote();
    ListSequence.fromList(mySuspendedContexts).insertElement(0, context);
    return context.isProcessed();
  }
  /*package*/ synchronized void voteResume(EventContext context) {
    context.vote();
    if (context.isProcessed() && !(ListSequence.fromList(mySuspendedContexts).contains(context))) {
      resume(context);
    }
  }
  /*package*/ void pauseUserContext(UserContext context) {
    myUserContext = context;
  }
  /*package*/ synchronized void resume(Context context) {
    if (context instanceof EventContext) {
      assert ((EventContext) context).isProcessed();
      ListSequence.fromList(mySuspendedContexts).removeElement((EventContext) context);
      tryResume5Times((EventContext) context, new _FunctionTypes._void_P1_E0<EventContext>() {
        public void invoke(EventContext c) {
          c.resume();
        }
      });
    } else if (context instanceof UserContext) {
      assert myUserContext == context;
      myUserContext = null;
      // I do not want to have resume method in the interface and do not want to create a class 
      tryResume5Times(((UserContext) context), new _FunctionTypes._void_P1_E0<UserContext>() {
        public void invoke(UserContext c) {
          c.resume();
        }
      });
    } else {
      assert false : "Do not know what kind of context it is " + context;
    }
  }
  private <C extends Context> void tryResume5Times(C context, _FunctionTypes._void_P1_E0<? super C> resume) {
    int resumeAttempts = 5;
    while (--resumeAttempts > 0) {
      try {
        resume.invoke(context);
        break;
      } catch (ObjectCollectedException e) {
        //  according to error reports set.resume() may throw this if one of the threads has been collected 
      } catch (InternalException e) {
        // InternalException 13 means that there are running threads that we are trying to resume 
        // On MacOS it happened that native thread didn't stop while some java thread reached breakpoint 
        if (e.errorCode() == 13 && context.getSuspendPolicy() == EventRequest.SUSPEND_ALL) {
          // Patches.MAC_RESUME_VM_HACK &&  
          // Its funny, but second resume solves the problem 
        } else {
          if (LOG.isEnabledFor(Level.ERROR)) {
            LOG.error("", e);
          }
          break;
        }
      }
    }
  }
  @Nullable
  public synchronized Context firstContext() {
    if (myUserContext != null) {
      return myUserContext;
    }
    if (ListSequence.fromList(mySuspendedContexts).isNotEmpty()) {
      ListSequence.fromList(mySuspendedContexts).first();
    }
    return null;
  }
  @Nullable
  public synchronized Context findContextForThread(final ThreadReference threadReference) {
    EventContext context = ListSequence.fromList(mySuspendedContexts).findFirst(new IWhereFilter<EventContext>() {
      public boolean accept(EventContext it) {
        return eq_toclu7_a0a0a0a0a0a0a01(it.getThread(), threadReference);
      }
    });
    if (context != null) {
      return context;
    }
    context = ListSequence.fromList(mySuspendedContexts).findFirst(new IWhereFilter<EventContext>() {
      public boolean accept(EventContext it) {
        return it.getSuspendPolicy() == EventRequest.SUSPEND_ALL;
      }
    });
    if (context != null) {
      return context;
    }
    if (myUserContext != null) {
      return myUserContext;
    }
    return null;
  }
  public synchronized boolean isPausedOnEvent(Context context) {
    return ListSequence.fromList(mySuspendedContexts).contains(context);
  }
  private static boolean eq_toclu7_a0a0a0a0a0a0a01(Object a, Object b) {
    return (a != null ? a.equals(b) : a == b);
  }
}