TryRunPlatformWriteHelper.java

/*
 * Copyright 2003-2017 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package jetbrains.mps.smodel;

import com.intellij.openapi.application.Application;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.command.CommandProcessor;
import com.intellij.openapi.command.UndoConfirmationPolicy;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.util.Computable;
import jetbrains.mps.ide.ThreadUtils;
import jetbrains.mps.util.ComputeRunnable;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.mps.annotations.Immutable;

import java.util.concurrent.DelayQueue;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

import static java.util.concurrent.TimeUnit.MILLISECONDS;

/**
 * Since the IDEA platform seems not to have any primitive #tryWrite to invoke
 * and we sometimes experience long reads (e.g. Highlighter) we are forced to
 * start a separate thread which waits for some time and then interrupts
 *
 * @author apyshkin
 * @since 2017.2
 *
 * TODO request #tryLock method from the IDEA platform
 */
@Immutable
final class TryRunPlatformWriteHelper {
  private static final int WAIT_FOR_WRITE_LOCK_MS = 200;

  private final WriteActionTracker myWriteActionTracker;
  private final DelayQueue<DelayedInterrupt> myInterruptQueue = new DelayQueue<>();

  TryRunPlatformWriteHelper(@NotNull WriteActionTracker writeActionTracker) {
    myWriteActionTracker = writeActionTracker;
    myInterruptingThread.start();
  }

  private final Thread myInterruptingThread = new Thread(() -> {
    while (true) {
      try {
        DelayedInterrupt di = myInterruptQueue.take();
        di.timeIsUp();
      } catch (InterruptedException e) {
        Application app = ApplicationManager.getApplication();
        if (app == null || app.isDisposeInProgress() || app.isDisposed()) {
          return;
        }
      }
    }
  }, "MPS interrupting thread");

  public void dispose() {
    for (int attempt = 3; attempt > 0 && myInterruptingThread.isAlive(); --attempt) {
      myInterruptingThread.interrupt();
      try {
        myInterruptingThread.join(500);
      } catch (InterruptedException e) {
        break;
      }
    }
  }

  private void cancelInterrupt(DelayedInterrupt di) {
    myInterruptQueue.remove(di);
  }

  private DelayedInterrupt interruptLater(Thread toInterrupt, long delay, TimeUnit unit) {
    DelayedInterrupt di = new DelayedInterrupt(toInterrupt, delay, unit);
    myInterruptQueue.put(di);
    return di;
  }

  void tryCommand(@NotNull Project project, @NotNull Runnable runnable) throws WriteTimeOutException {
    ComputeRunnable<WriteTimeOutException> computable = new ComputeRunnable<>(() -> {
      TryWriteActionRunnable tryWriteAction = new TryWriteActionRunnable(runnable);
      try {
        tryWriteAction.tryWrite();
      } catch (WriteTimeOutException e) {
        return e;
      }
      return null;
    });
    executeCommand(project, computable);
    if (computable.getResult() != null) {
      throw computable.getResult();
    }
  }

  private void executeCommand(@NotNull Project project, ComputeRunnable<?> computable) {
    CommandProcessor.getInstance().executeCommand(
        project,
        computable,
        "MPS #tryCommand",
        null,
        UndoConfirmationPolicy.DO_NOT_REQUEST_CONFIRMATION);
  }

  <T> T tryWrite(Computable<T> computable) throws WriteTimeOutException {
    ComputeRunnable<T> toCompute = new ComputeRunnable<>(computable::compute);
    new TryWriteActionRunnable(toCompute).tryWrite();
    return toCompute.getResult();
  }

  @Immutable
  private final class TryWriteActionRunnable {
    private final Runnable myRunnable;

    TryWriteActionRunnable(Runnable runnable) {
      myRunnable = runnable;
    }

    void tryWrite() throws WriteTimeOutException {
      ThreadUtils.assertEDT();
      // workaround for IDEA's locks shortcoming: timeout on write action
      Thread.interrupted();
      final DelayedInterrupt delayedInterrupt = interruptLater(Thread.currentThread(), WAIT_FOR_WRITE_LOCK_MS, MILLISECONDS);
      try {
        myWriteActionTracker.writeActionScheduled();
        ApplicationManager.getApplication().runWriteAction(() -> {
          cancelInterrupt(delayedInterrupt);
          myRunnable.run();
        });
      } catch (RuntimeException re) {
        dealWithRuntimeException(delayedInterrupt, re);
      } finally {
        myWriteActionTracker.writeActionProcessed();
      }
    }

    private void dealWithRuntimeException(DelayedInterrupt delayedInterrupt, RuntimeException re) throws WriteTimeOutException {
      cancelInterrupt(delayedInterrupt);
      RuntimeException cause = getCause(re);
      if (cause.getCause() instanceof InterruptedException) {
        if (delayedInterrupt.isInterruptSuccessful()) {
          throw new WriteTimeOutException(cause.getCause());
        } else {
          throw cause;
        }
      } else {
        throw cause;
      }
    }

    @NotNull
    private RuntimeException getCause(RuntimeException re) {
      while (re.getCause() instanceof RuntimeException) {
        re = (RuntimeException) re.getCause();
      }
      return re;
    }
  }

  private static class DelayedInterrupt implements Delayed {
    private final long myAlarmTimeNanos;
    private final Thread myToInterrupt;
    private boolean myInterruptSuccess;

    private DelayedInterrupt(@NotNull Thread toInterrupt, long delay, TimeUnit unit) {
      myToInterrupt = toInterrupt;
      myAlarmTimeNanos = System.nanoTime() + unit.toNanos(delay);
    }

    private void timeIsUp() {
      myInterruptSuccess = myToInterrupt.isInterrupted();
    }

    boolean isInterruptSuccessful() {
      return myInterruptSuccess;
    }

    @Override
    public long getDelay(@NotNull TimeUnit unit) {
      return unit.convert(myAlarmTimeNanos - System.nanoTime(), TimeUnit.NANOSECONDS);
    }

    @Override
    public int compareTo(@NotNull Delayed that) {
      if (!(that instanceof DelayedInterrupt)) {
        throw new ClassCastException();
      }
      return (int) (myAlarmTimeNanos - ((DelayedInterrupt) that).myAlarmTimeNanos);
    }
  }
}