/*******************************************************************************
* Copyright (c) 2014 Red Hat, Inc.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Red Hat - initial API and implementation
*******************************************************************************/
package org.eclipse.linuxtools.internal.systemtap.ui.ide.structures.tparsers;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.jobs.IJobChangeListener;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.linuxtools.internal.systemtap.ui.ide.structures.Messages;
import org.eclipse.linuxtools.systemtap.structures.TreeNode;
/**
* A base abstract class to be used for extensions of {@link TapsetParser}
* that construct a displayable {@link TreeNode}.
*/
public abstract class TreeTapsetParser extends TapsetParser {
private class TapsetChanges {
private String[] additions;
private String[] deletions;
private TapsetChanges(String[] additions, String[] deletions) {
this.additions = new String[additions.length];
this.deletions = new String[deletions.length];
System.arraycopy(additions, 0, this.additions, 0, additions.length);
System.arraycopy(deletions, 0, this.deletions, 0, deletions.length);
}
}
private final Object lock = new Object();
protected TreeNode tree = new TreeNode(null, false);
private TreeNode forcedTree = null;
private TapsetChanges tapsetChanges = null;
protected TreeTapsetParser(String jobTitle) {
super(jobTitle);
}
/**
* Adds a listener to this job and returns this job's latest result, which will
* not be pre-empted by another job completing. Clients should call this instead of
* {@link #addJobChangeListener(IJobChangeListener)} only when knowing the previous
* job result is required for synchronization purposes (such as UI updating).
* @param listener the listener to be added.
* @return The result of {@link #getLatestResult()}.
* @see #addJobChangeListener(IJobChangeListener)
* @see #getLatestResult()
*/
public IStatus safelyAddJobChangeListener(IJobChangeListener listener) {
synchronized (lock) {
super.addJobChangeListener(listener);
return getLatestResult();
}
}
/**
* Gets the result of the last job that was started, rather than the last job
* that was finished. This should only be used when a {@link IJobChangeListener}
* is already registered with this job, so true job completion can be caught.
* @return The result of this job's last run, or null if this job has either
* never finished running or is currently running.
* @see #getResult()
*/
public IStatus getLatestResult() {
synchronized (lock) {
return getState() != Job.RUNNING ? getResult() : null;
}
}
/**
* Prepares the parser for a run. Clients must override this method to perform
* actions during the run; a call to super.run() is necessary.
*/
@Override
protected final synchronized IStatus run(IProgressMonitor monitor) {
IStatus result;
if (forcedTree != null) {
if (isValidTree(forcedTree)) {
tree = forcedTree;
result = createStatus(IStatus.OK);
} else {
result = createStatus(IStatus.ERROR, Messages.TapsetParser_ErrorInvalidTapsetTree);
}
forcedTree = null;
} else if (tapsetChanges != null) {
result = performUpdate(monitor);
} else {
tree = new TreeNode(null, false);
result = createStatus(runAction(monitor));
}
synchronized (lock) {
return result;
}
}
/**
* Loads the tapset contents and saves them.
* @param monitor The progress monitor for the operation.
* @return An {@link IStatus} severity level for the result of the operation.
*/
protected abstract int runAction(IProgressMonitor monitor);
/**
* After adding / removing tapsets, schedule the job that
* loads in / discards the tapsets that were added / removed.
* @param additions The list of added tapset directories.
* @param deletions The list of removed tapset directories.
*/
public synchronized void runUpdate(String[] additions, String[] deletions) {
tapsetChanges = new TapsetChanges(additions, deletions);
schedule();
}
/**
* Performs both stages of a tapset update operation, ensuring that the new
* tapset contents will be available when they are necessary.
* @param monitor The operation's progress monitor.
* @return The status of the operation's outcome.
*/
private IStatus performUpdate(IProgressMonitor monitor) {
int result = IStatus.OK;
if (tapsetChanges.deletions.length > 0) {
result = delTapsets(tapsetChanges.deletions, monitor);
}
if (result == IStatus.OK && tapsetChanges.additions.length > 0) {
if (monitor.isCanceled()) {
result = IStatus.CANCEL;
} else {
String tapsetContents = SharedParser.getInstance().getTapsetContents();
result = verifyRunResult(tapsetContents);
if (result == IStatus.OK) {
result = addTapsets(tapsetContents, tapsetChanges.additions, monitor);
}
}
}
tapsetChanges = null;
return createStatus(result);
}
/**
* After changing the list of imported tapsets, discards the tapsets that were removed.
* @param deletions A non-empty list of removed tapset directories.
* @param monitor The progress monitor for the operation.
* @return An {@link IStatus} severity level for the result of the operation.
*/
protected abstract int delTapsets(String[] deletions, IProgressMonitor monitor);
/**
* After changing the list of imported tapsets, loads in the tapsets that were added.
* Tapset contents are guaranteed to be loaded at the time this method is called.
* @param tapsetContents the set of tapset contents as generated by {@link SharedParser#getTapsetContents()}.
* Included as a parameter to have the caller manage the tapset instead of the callee.
* @param additions A non-empty list of added tapset directories.
* @param monitor The progress monitor for the operation.
* @return An {@link IStatus} severity level for the result of the operation.
*/
protected abstract int addTapsets(String tapsetContents, String[] additions, IProgressMonitor monitor);
/**
* @return The tree that this parser constructs. Guaranteed not be null.
*/
public final TreeNode getTree() {
return tree;
}
/**
* Forcefully set this parser's tree, and subsequently fire update events
* that normally get called when a parse operation completes.
* @param tree The tree to put into this parser.
*/
public final void setTree(TreeNode tree) {
cancel();
forcedTree = tree;
schedule();
}
/**
* Check if the provided tree a valid tree for this parser.
* Called internally by {@link #setTree(TreeNode)}.
* @param tree The tree to check for validity.
* @return <code>true</code> if the tree is valid, <code>false</code> otherwise.
*/
protected boolean isValidTree(TreeNode tree) {
return tree != null;
}
}