| /******************************************************************************* |
| * Copyright (c) 2000, 2016 IBM Corporation and others. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0. |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| *******************************************************************************/ |
| package org.eclipse.dltk.internal.core.search.processing; |
| |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| import org.eclipse.core.runtime.IProgressMonitor; |
| import org.eclipse.core.runtime.OperationCanceledException; |
| import org.eclipse.core.runtime.SubMonitor; |
| import org.eclipse.dltk.core.DLTKCore; |
| import org.eclipse.dltk.internal.core.util.Messages; |
| import org.eclipse.dltk.internal.core.util.Util; |
| import org.eclipse.osgi.util.NLS; |
| |
| public abstract class JobManager implements Runnable { |
| |
| /* enable delay between processing jobs if single core || multithreading */ |
| private static final boolean ENABLE_DELAYS = Runtime.getRuntime().availableProcessors() == 1; |
| |
| /* queue of jobs to execute */ |
| protected IJob[] awaitingJobs = new IJob[10]; |
| protected int jobStart = 0; |
| protected int jobEnd = -1; |
| protected boolean executing = false; |
| |
| /* background processing */ |
| protected Thread processingThread; |
| |
| /* |
| * counter indicating whether job execution is enabled or not, disabled if <= 0 |
| * it cannot go beyond 1 |
| */ |
| private int enableCount = 1; |
| |
| public final static boolean VERBOSE = DLTKCore.VERBOSE_JOBMANAGER; |
| /* flag indicating that the activation has completed */ |
| public boolean activated = false; |
| |
| private final AtomicInteger awaitingClients = new AtomicInteger(); |
| |
| /** |
| * Invoked exactly once, in background, before starting processing any job |
| */ |
| public void activateProcessing() { |
| this.activated = true; |
| } |
| |
| /** |
| * Answer the amount of awaiting jobs. |
| */ |
| public synchronized int awaitingJobsCount() { |
| // pretend busy in case concurrent job attempts performing before |
| // activated |
| return this.activated ? this.jobEnd - this.jobStart + 1 : 1; |
| } |
| |
| /** |
| * Answers the first job in the queue, or null if there is no job available |
| * Until the job has completed, the job manager will keep answering the same |
| * job. |
| */ |
| public synchronized IJob currentJob() { |
| if (this.enableCount > 0 && this.jobStart <= this.jobEnd) |
| return this.awaitingJobs[this.jobStart]; |
| return null; |
| } |
| |
| public void disable() { |
| this.enableCount--; |
| if (VERBOSE) |
| Util.verbose("DISABLING background indexing"); //$NON-NLS-1$ |
| } |
| |
| /** |
| * Remove the index from cache for a given project. Passing null as a job family |
| * discards them all. |
| */ |
| public void discardJobs(String jobFamily) { |
| |
| if (VERBOSE) |
| Util.verbose("DISCARD background job family - " + jobFamily); //$NON-NLS-1$ |
| |
| try { |
| IJob currentJob; |
| // cancel current job if it belongs to the given family |
| synchronized (this) { |
| currentJob = this.currentJob(); |
| disable(); |
| } |
| if (currentJob != null && (jobFamily == null || currentJob.belongsTo(jobFamily))) { |
| currentJob.cancel(); |
| |
| // wait until current active job has finished |
| while (this.processingThread != null && this.executing) { |
| try { |
| if (VERBOSE) |
| Util.verbose("-> waiting end of current background job - " + currentJob); //$NON-NLS-1$ |
| Thread.sleep(50); |
| } catch (InterruptedException e) { |
| // ignore |
| } |
| } |
| } |
| |
| // flush and compact awaiting jobs |
| int loc = -1; |
| synchronized (this) { |
| for (int i = this.jobStart; i <= this.jobEnd; i++) { |
| currentJob = this.awaitingJobs[i]; |
| if (currentJob != null) { // sanity check |
| this.awaitingJobs[i] = null; |
| if (!(jobFamily == null || currentJob.belongsTo(jobFamily))) { // copy down, |
| // compacting |
| this.awaitingJobs[++loc] = currentJob; |
| } else { |
| if (VERBOSE) |
| Util.verbose("-> discarding background job - " + currentJob); //$NON-NLS-1$ |
| currentJob.cancel(); |
| } |
| } |
| } |
| this.jobStart = 0; |
| this.jobEnd = loc; |
| } |
| } finally { |
| enable(); |
| } |
| if (VERBOSE) |
| Util.verbose("DISCARD DONE with background job family - " + jobFamily); //$NON-NLS-1$ |
| } |
| |
| public synchronized void enable() { |
| this.enableCount++; |
| if (VERBOSE) |
| Util.verbose("ENABLING background indexing"); //$NON-NLS-1$ |
| this.notifyAll(); // wake up the background thread if it is waiting |
| // (context must be synchronized) |
| } |
| |
| public synchronized boolean isJobWaiting(IJob request) { |
| for (int i = this.jobEnd; i > this.jobStart; i--) |
| // don't check job at jobStart, as it may have already started |
| if (request.equals(this.awaitingJobs[i])) |
| return true; |
| return false; |
| } |
| |
| /** |
| * Advance to the next available job, once the current one has been completed. |
| * Note: clients awaiting until the job count is zero are still waiting at this |
| * point. |
| */ |
| protected synchronized void moveToNextJob() { |
| // if (!enabled) return; |
| |
| if (this.jobStart <= this.jobEnd) { |
| this.awaitingJobs[this.jobStart++] = null; |
| if (this.jobStart > this.jobEnd) { |
| this.jobStart = 0; |
| this.jobEnd = -1; |
| } |
| } |
| } |
| |
| /** |
| * Notifies that processing thread idle state has come to an end. |
| */ |
| protected void notifyIdle(long idlingTime) { |
| // do nothing |
| } |
| |
| /** |
| * Notifies that processing thread is going to idle state. |
| */ |
| protected void notifyIdle() { |
| // do nothing |
| } |
| |
| /** |
| * This API is allowing to run one job in concurrence with background |
| * processing. Indeed since other jobs are performed in background, resource |
| * sharing might be an issue.Therefore, this functionality allows a given job to |
| * be run without colliding with background ones. Note: multiple thread might |
| * attempt to perform concurrent jobs at the same time, and should synchronize |
| * (it is deliberately left to clients to decide whether concurrent jobs might |
| * interfere or not. In general, multiple read jobs are ok). |
| * |
| * Waiting policy can be: IJobConstants.ForceImmediateSearch |
| * IJobConstants.CancelIfNotReadyToSearch IJobConstants.WaitUntilReadyToSearch |
| * |
| */ |
| public boolean performConcurrentJob(IJob searchJob, int waitingPolicy, IProgressMonitor monitor) { |
| if (VERBOSE) |
| Util.verbose("STARTING concurrent job - " + searchJob); //$NON-NLS-1$ |
| |
| boolean status = IJob.FAILED; |
| searchJob.ensureReadyToRun(); |
| try { |
| SubMonitor subMonitor = SubMonitor.convert(monitor); |
| if (awaitingJobsCount() > 0) { |
| switch (waitingPolicy) { |
| |
| case IJob.ForceImmediate: |
| if (VERBOSE) |
| Util.verbose("-> NOT READY - forcing immediate - " + searchJob);//$NON-NLS-1$ |
| try { |
| disable(); // pause indexing |
| status = searchJob.execute(subMonitor); |
| } finally { |
| enable(); |
| } |
| if (VERBOSE) |
| Util.verbose("FINISHED concurrent job - " + searchJob); //$NON-NLS-1$ |
| return status; |
| |
| case IJob.CancelIfNotReady: |
| if (VERBOSE) |
| Util.verbose("-> NOT READY - cancelling - " + searchJob); //$NON-NLS-1$ |
| if (VERBOSE) |
| Util.verbose("CANCELED concurrent job - " + searchJob); //$NON-NLS-1$ |
| throw new OperationCanceledException(); |
| |
| case IJob.WaitUntilReady: |
| SubMonitor subProgress = subMonitor.setWorkRemaining(10).split(8).setWorkRemaining(1000); |
| |
| synchronized (delaySignal) { |
| delaySignal.notify(); |
| } |
| // use local variable to avoid potential NPE (see bug 20435 NPE |
| // when searchingscriptmethod |
| // and bug 42760 NullPointerException in JobManager when |
| // searching) |
| Thread t = this.processingThread; |
| int originalPriority = t == null ? -1 : t.getPriority(); |
| try { |
| if (t != null) |
| t.setPriority(Thread.currentThread().getPriority()); |
| this.awaitingClients.incrementAndGet(); |
| IJob previousJob = null; |
| int awaitingWork; |
| while ((awaitingWork = awaitingJobsCount()) > 0) { |
| if (subProgress != null && subProgress.isCanceled()) |
| throw new OperationCanceledException(); |
| final IJob currentJob = currentJob(); |
| // currentJob can be null when jobs have been added to |
| // the queue but job manager is not enabled |
| if (currentJob != null && currentJob != previousJob) { |
| if (VERBOSE) |
| Util.verbose("-> NOT READY - waiting until ready - " + searchJob);//$NON-NLS-1$ |
| subProgress.subTask( |
| NLS.bind(Messages.manager_filesToIndex, Integer.toString(awaitingWork))); |
| subProgress.worked(1); |
| previousJob = currentJob; |
| } |
| try { |
| if (VERBOSE) |
| Util.verbose("-> GOING TO SLEEP - " + searchJob);//$NON-NLS-1$ |
| Thread.sleep(50); |
| } catch (InterruptedException e) { |
| // ignore |
| } |
| } |
| } finally { |
| this.awaitingClients.decrementAndGet(); |
| if (t != null && originalPriority > -1 && t.isAlive()) |
| t.setPriority(originalPriority); |
| } |
| } |
| } |
| status = searchJob.execute(subMonitor); |
| if (VERBOSE) |
| Util.verbose("FINISHED concurrent job - " + searchJob); //$NON-NLS-1$ |
| } finally { |
| SubMonitor.done(monitor); |
| } |
| return status; |
| } |
| |
| public abstract String processName(); |
| |
| private static final class WaitJob implements IJob { |
| @Override |
| public boolean belongsTo(String jobFamily) { |
| return false; |
| } |
| |
| @Override |
| public void cancel() { |
| } |
| |
| @Override |
| public void ensureReadyToRun() { |
| } |
| |
| @Override |
| public boolean execute(IProgressMonitor progress) { |
| return false; |
| } |
| |
| @Override |
| public String toString() { |
| return "WAIT-UNTIL-READY-JOB"; //$NON-NLS-1$ |
| } |
| } |
| |
| public void waitUntilReady() { |
| performConcurrentJob(new WaitJob(), IJob.WaitUntilReady, null); |
| } |
| |
| /** |
| * @since 2.0 |
| */ |
| public void requestIfNotWaiting(IJob job) { |
| if (!isJobWaiting(job)) { |
| request(job); |
| } |
| } |
| |
| public synchronized void request(IJob job) { |
| |
| job.ensureReadyToRun(); |
| |
| // append the job to the list of ones to process later on |
| int size = this.awaitingJobs.length; |
| if (++this.jobEnd == size) { // when growing, relocate jobs starting at |
| // position 0 |
| this.jobEnd -= this.jobStart; |
| System.arraycopy(this.awaitingJobs, this.jobStart, this.awaitingJobs = new IJob[size * 2], 0, this.jobEnd); |
| this.jobStart = 0; |
| } |
| this.awaitingJobs[this.jobEnd] = job; |
| if (VERBOSE) { |
| Util.verbose("REQUEST background job - " + job); //$NON-NLS-1$ |
| Util.verbose("AWAITING JOBS count: " + awaitingJobsCount()); //$NON-NLS-1$ |
| } |
| notifyAll(); // wake up the background thread if it is waiting |
| } |
| |
| /** |
| * Flush current state |
| */ |
| public synchronized void reset() { |
| if (VERBOSE) |
| Util.verbose("Reset"); //$NON-NLS-1$ |
| |
| if (this.processingThread != null) { |
| discardJobs(null); // discard all jobs |
| } else { |
| /* initiate background processing */ |
| this.processingThread = new Thread(this, this.processName()); |
| this.processingThread.setDaemon(true); |
| // less prioritary by default, priority is raised if clients are |
| // actively waiting on it |
| this.processingThread.setPriority(Thread.NORM_PRIORITY - 1); |
| this.processingThread.start(); |
| } |
| } |
| |
| /** |
| * is used for delaying before processing new jobs, that could be canceled by |
| * {@link #performConcurrentJob()} if called with {@link IJob#WaitUntilReady} |
| */ |
| private final Object delaySignal = new Object(); |
| |
| /** |
| * Infinite loop performing resource indexing |
| */ |
| @Override |
| public void run() { |
| long idlingStart = -1; |
| activateProcessing(); |
| try { |
| while (this.processingThread != null) { |
| try { |
| IJob job; |
| synchronized (this) { |
| // handle shutdown case when notifyAll came before the |
| // wait but after the while loop was entered |
| if (this.processingThread == null) |
| continue; |
| |
| // must check for new job inside this sync block to |
| // avoid timing hole |
| if ((job = currentJob()) == null) { |
| if (idlingStart < 0) { |
| idlingStart = System.currentTimeMillis(); |
| notifyIdle(); |
| } else |
| notifyIdle(System.currentTimeMillis() - idlingStart); |
| this.wait(); // wait until a new job is posted (or |
| // reenabled:38901) |
| } else { |
| idlingStart = -1; |
| } |
| } |
| if (job == null) { |
| notifyIdle(System.currentTimeMillis() - idlingStart); |
| // just woke up, delay before processing any new jobs, |
| // allow some time for the active thread to finish |
| synchronized (delaySignal) { |
| delaySignal.wait(50); |
| } |
| continue; |
| } |
| if (VERBOSE) { |
| Util.verbose(awaitingJobsCount() + " awaiting jobs"); //$NON-NLS-1$ |
| Util.verbose("STARTING background job - " + job); //$NON-NLS-1$ |
| } |
| try { |
| this.executing = true; |
| /* boolean status = */job.execute(null); |
| // if (status == FAILED) request(job); |
| } finally { |
| this.executing = false; |
| if (VERBOSE) |
| Util.verbose("FINISHED background job - " + job); //$NON-NLS-1$ |
| moveToNextJob(); |
| if (ENABLE_DELAYS && this.awaitingClients.get() == 0) |
| Thread.sleep(50); |
| } |
| } catch (InterruptedException e) { // background indexing was |
| // interrupted |
| } |
| } |
| } catch (RuntimeException e) { |
| if (this.processingThread != null) { // if not shutting down |
| // keep job manager alive |
| this.discardJobs(null); |
| this.processingThread = null; |
| this.reset(); // this will fork a new thread with no waiting |
| // jobs, some indexes will be inconsistent |
| |
| // log exception |
| Util.log(e, "Background Indexer Crash Recovery"); //$NON-NLS-1$ |
| } |
| throw e; |
| } catch (Error e) { |
| if (this.processingThread != null && !(e instanceof ThreadDeath)) { |
| // keep job manager alive |
| this.discardJobs(null); |
| this.processingThread = null; |
| this.reset(); // this will fork a new thread with no waiting |
| // jobs, some indexes will be inconsistent |
| |
| // log exception |
| Util.log(e, "Background Indexer Crash Recovery"); //$NON-NLS-1$ |
| } |
| throw e; |
| } |
| } |
| |
| /** |
| * Stop background processing, and wait until the current job is completed |
| * before returning |
| */ |
| public void shutdown() { |
| |
| if (VERBOSE) |
| Util.verbose("Shutdown"); //$NON-NLS-1$ |
| |
| disable(); |
| discardJobs(null); // will wait until current executing job has |
| // completed |
| Thread thread = this.processingThread; |
| try { |
| if (thread != null) { // see |
| // http://bugs.eclipse.org/bugs/show_bug.cgi |
| // ?id=31858 |
| synchronized (this) { |
| this.processingThread = null; // mark the job manager as |
| // shutting down so that the |
| // thread will stop by |
| // itself |
| this.notifyAll(); // ensure its awake so it can be shutdown |
| } |
| // in case processing thread is handling a job |
| // XXX wait not more than 1 minute |
| thread.join(60000); |
| } |
| } catch (InterruptedException e) { |
| // ignore |
| } |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder buffer = new StringBuilder(64); |
| buffer.append("Enable count:").append(this.enableCount).append('\n'); //$NON-NLS-1$ |
| int numJobs = this.jobEnd - this.jobStart + 1; |
| buffer.append("Jobs in queue:").append(numJobs).append('\n'); //$NON-NLS-1$ |
| for (int i = 0; i < numJobs && i < 15; i++) { |
| buffer.append(i).append(" - job[" + i + "]: ").append(this.awaitingJobs[this.jobStart + i]).append('\n'); //$NON-NLS-1$ //$NON-NLS-2$ |
| } |
| return buffer.toString(); |
| } |
| } |