/*******************************************************************************
* Copyright (c) 2004, 2009 IBM Corporation and others.
* 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.core.internal.resources;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
import org.eclipse.core.filesystem.EFS;
import org.eclipse.core.filesystem.IFileStore;
import org.eclipse.core.internal.events.ILifecycleListener;
import org.eclipse.core.internal.events.LifecycleEvent;
import org.eclipse.core.internal.utils.*;
import org.eclipse.core.internal.watson.*;
import org.eclipse.core.resources.*;
import org.eclipse.core.runtime.*;
import org.eclipse.core.runtime.content.*;
import org.eclipse.core.runtime.content.IContentTypeManager.ContentTypeChangeEvent;
import org.eclipse.core.runtime.jobs.ISchedulingRule;
import org.eclipse.osgi.util.NLS;
import org.osgi.framework.Bundle;
/**
* Keeps a cache of recently read content descriptions.
*
* @since 3.0
* @see IFile#getContentDescription()
*/
public class ContentDescriptionManager implements IManager, IRegistryChangeListener, IContentTypeManager.IContentTypeChangeListener, ILifecycleListener {
/**
* This job causes the content description cache and the related flags in the resource tree to
* be flushed.
*/
private class FlushJob extends WorkspaceJob {
private final List toFlush;
private boolean fullFlush;
public FlushJob() {
super(Messages.resources_flushingContentDescriptionCache);
setSystem(true);
setUser(false);
setPriority(LONG);
setRule(workspace.getRoot());
toFlush= new ArrayList(5);
}
/* (non-Javadoc)
* See Job#belongsTo(Object)
*/
public boolean belongsTo(Object family) {
return FAMILY_DESCRIPTION_CACHE_FLUSH.equals(family);
}
/* (non-Javadoc)
* See WorkspaceJob#runInWorkspace(IProgressMonitor)
*/
public IStatus runInWorkspace(final IProgressMonitor monitor) {
if (monitor.isCanceled())
return Status.CANCEL_STATUS;
try {
monitor.beginTask("", Policy.opWork); //$NON-NLS-1$
//note that even though we are running in a workspace job, we
//must do a begin/endOperation to re-acquire the workspace lock
final ISchedulingRule rule= workspace.getRoot();
try {
workspace.prepareOperation(rule, monitor);
workspace.beginOperation(true);
//don't do anything if the system is shutting down or has been shut down
//it is too late to change the workspace at this point anyway
if (systemBundle.getState() != Bundle.STOPPING)
doFlushCache(monitor, getPathsToFlush());
} finally {
workspace.endOperation(rule, false, Policy.subMonitorFor(monitor, Policy.endOpWork));
}
} catch (OperationCanceledException e) {
return Status.CANCEL_STATUS;
} catch (CoreException e) {
return e.getStatus();
} finally {
monitor.done();
}
return Status.OK_STATUS;
}
private IPath[] getPathsToFlush() {
synchronized (toFlush) {
try {
if (fullFlush)
return null;
int size= toFlush.size();
return (size == 0) ? null : (IPath[])toFlush.toArray(new IPath[size]);
} finally {
fullFlush= false;
toFlush.clear();
}
}
}
/**
* @param project project to flush, or null for a full flush
*/
void flush(IProject project) {
if (Policy.DEBUG_CONTENT_TYPE_CACHE)
Policy.debug("Scheduling flushing of content type cache for " + (project == null ? Path.ROOT : project.getFullPath())); //$NON-NLS-1$
synchronized (toFlush) {
if (!fullFlush)
if (project == null)
fullFlush= true;
else
toFlush.add(project.getFullPath());
}
schedule(1000);
}
}
/**
* An input stream that only opens the file if bytes are actually requested.
*
* @see #readDescription(File)
*/
class LazyFileInputStream extends InputStream {
private InputStream actual;
private IFileStore target;
LazyFileInputStream(IFileStore target) {
this.target= target;
}
public int available() throws IOException {
if (actual == null)
return 0;
return actual.available();
}
public void close() throws IOException {
if (actual == null)
return;
actual.close();
}
private void ensureOpened() throws IOException {
if (actual != null)
return;
if (target == null)
throw new FileNotFoundException();
try {
actual= target.openInputStream(EFS.NONE, null);
} catch (CoreException e) {
throw new IOException(e.getMessage());
}
}
public int read() throws IOException {
ensureOpened();
return actual.read();
}
public int read(byte[] b, int off, int len) throws IOException {
ensureOpened();
return actual.read(b, off, len);
}
public long skip(long n) throws IOException {
ensureOpened();
return actual.skip(n);
}
}
private static final QualifiedName CACHE_STATE= new QualifiedName(ResourcesPlugin.PI_RESOURCES, "contentCacheState"); //$NON-NLS-1$
private static final QualifiedName CACHE_TIMESTAMP= new QualifiedName(ResourcesPlugin.PI_RESOURCES, "contentCacheTimestamp"); //$NON-NLS-1$\
public static final String FAMILY_DESCRIPTION_CACHE_FLUSH= ResourcesPlugin.PI_RESOURCES + ".contentDescriptionCacheFamily"; //$NON-NLS-1$
//possible values for the CACHE_STATE property
public static final byte EMPTY_CACHE= 1;
public static final byte USED_CACHE= 2;
public static final byte INVALID_CACHE= 3;
public static final byte FLUSHING_CACHE= 4;
// This state indicates that FlushJob is scheduled and full flush is going to be performed.
// In the meantime the cache was discarded. It is used as a temporary cache till the FlushJob start.
public static final byte ABOUT_TO_FLUSH= 5;
private static final String PT_CONTENTTYPES= "contentTypes"; //$NON-NLS-1$
private Cache cache;
private byte cacheState;
private FlushJob flushJob;
private ProjectContentTypes projectContentTypes;
Workspace workspace;
protected final Bundle systemBundle= Platform.getBundle("org.eclipse.osgi"); //$NON-NLS-1$
/**
* @see IContentTypeManager.IContentTypeChangeListener#contentTypeChanged(IContentTypeManager.ContentTypeChangeEvent)
*/
public void contentTypeChanged(ContentTypeChangeEvent event) {
if (Policy.DEBUG_CONTENT_TYPE)
Policy.debug("Content type settings changed for " + event.getContentType()); //$NON-NLS-1$
invalidateCache(true, null);
}
synchronized void doFlushCache(final IProgressMonitor monitor, IPath[] toClean) throws CoreException {
// nothing to be done if no information cached
if (getCacheState() != INVALID_CACHE && getCacheState() != ABOUT_TO_FLUSH) {
if (Policy.DEBUG_CONTENT_TYPE_CACHE)
Policy.debug("Content type cache flush not performed"); //$NON-NLS-1$
return;
}
try {
setCacheState(FLUSHING_CACHE);
// flush the MRU cache
cache.discardAll();
if (toClean == null || toClean.length == 0)
// no project was added, must be a global flush
clearContentFlags(Path.ROOT, monitor);
else {
// flush a project at a time
for (int i= 0; i < toClean.length; i++)
clearContentFlags(toClean[i], monitor);
}
} catch (CoreException ce) {
setCacheState(INVALID_CACHE);
throw ce;
}
// done cleaning (only if we didn't fail)
setCacheState(EMPTY_CACHE);
}
/**
* Clears the content related flags for every file under the given root.
*/
private void clearContentFlags(IPath root, final IProgressMonitor monitor) {
long flushStart= System.currentTimeMillis();
if (Policy.DEBUG_CONTENT_TYPE_CACHE)
Policy.debug("Flushing content type cache for " + root); //$NON-NLS-1$
// discard content type related flags for all files in the tree
IElementContentVisitor visitor= new IElementContentVisitor() {
public boolean visitElement(ElementTree tree, IPathRequestor requestor, Object elementContents) {
if (monitor.isCanceled())
throw new OperationCanceledException();
if (elementContents == null)
return false;
ResourceInfo info= (ResourceInfo)elementContents;
if (info.getType() != IResource.FILE)
return true;
info= workspace.getResourceInfo(requestor.requestPath(), false, true);
if (info == null)
return false;
info.clear(ICoreConstants.M_CONTENT_CACHE);
return true;
}
};
new ElementTreeIterator(workspace.getElementTree(), root).iterate(visitor);
if (Policy.DEBUG_CONTENT_TYPE_CACHE)
Policy.debug("Content type cache for " + root + " flushed in " + (System.currentTimeMillis() - flushStart) + " ms"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
Cache getCache() {
return cache;
}
/** Public so tests can examine it. */
public synchronized byte getCacheState() {
if (cacheState != 0)
// we have read/set it before, no nead to read property
return cacheState;
String persisted;
try {
persisted= workspace.getRoot().getPersistentProperty(CACHE_STATE);
cacheState= persisted != null ? Byte.parseByte(persisted) : INVALID_CACHE;
} catch (NumberFormatException e) {
cacheState= INVALID_CACHE;
} catch (CoreException e) {
Policy.log(e.getStatus());
cacheState= INVALID_CACHE;
}
return cacheState;
}
public long getCacheTimestamp() throws CoreException {
try {
return Long.parseLong(workspace.getRoot().getPersistentProperty(CACHE_TIMESTAMP));
} catch (NumberFormatException e) {
return 0;
}
}
public IContentTypeMatcher getContentTypeMatcher(Project project) throws CoreException {
return projectContentTypes.getMatcherFor(project);
}
public IContentDescription getDescriptionFor(File file, ResourceInfo info) throws CoreException {
if (ProjectContentTypes.usesContentTypePreferences(file.getFullPath().segment(0)))
// caching for project containing project specific settings is not supported
return readDescription(file);
if (getCacheState() == INVALID_CACHE) {
// discard the cache, so it can be used before the flush job starts
setCacheState(ABOUT_TO_FLUSH);
cache.discardAll();
// the cache is not good, flush it
flushJob.schedule(1000);
}
if (getCacheState() != ABOUT_TO_FLUSH) {
// first look for the flags in the resource info to avoid looking in the cache
// don't need to copy the info because the modified bits are not in the deltas
if (info == null)
return null;
if (info.isSet(ICoreConstants.M_NO_CONTENT_DESCRIPTION))
// presumably, this file has no known content type
return null;
if (info.isSet(ICoreConstants.M_DEFAULT_CONTENT_DESCRIPTION)) {
// this file supposedly has a default content description for an "obvious" content type
IContentTypeManager contentTypeManager= Platform.getContentTypeManager();
// try to find the obvious content type matching its name
IContentType type= contentTypeManager.findContentTypeFor(file.getName());
if (type != null)
// we found it, we are done
return type.getDefaultDescription();
// for some reason, there was no content type for this file name
// fix this and keep going
info.clear(ICoreConstants.M_CONTENT_CACHE);
}
}
synchronized (this) {
// tries to get a description from the cache
Cache.Entry entry= cache.getEntry(file.getFullPath());
if (entry != null && entry.getTimestamp() == getTimestamp(info))
// there was a description in the cache, and it was up to date
return (IContentDescription)entry.getCached();
}
// either we didn't find a description in the cache, or it was not up-to-date - has to be read again
// reading description can call 3rd party code, so don't synchronize it
IContentDescription newDescription= readDescription(file);
synchronized (this) {
// tries to get a description from the cache
Cache.Entry entry= cache.getEntry(file.getFullPath());
if (entry != null && entry.getTimestamp() == getTimestamp(info))
// there was a description in the cache, and it was up to date
return (IContentDescription)entry.getCached();
if (getCacheState() != ABOUT_TO_FLUSH) {
// we are going to add an entry to the cache or update the resource info - remember that
setCacheState(USED_CACHE);
if (newDescription == null) {
// no content type exists for this file name/contents - remember this
info.set(ICoreConstants.M_NO_CONTENT_DESCRIPTION);
return null;
}
if (newDescription.getContentType().getDefaultDescription().equals(newDescription)) {
// we got a default description
IContentType defaultForName= Platform.getContentTypeManager().findContentTypeFor(file.getName());
if (newDescription.getContentType().equals(defaultForName)) {
// it is a default description for the obvious content type given its file name, we don't have to cache
info.set(ICoreConstants.M_DEFAULT_CONTENT_DESCRIPTION);
return newDescription;
}
}
}
// we actually got a description filled by a describer (or a default description for a non-obvious type)
if (entry == null)
// there was no entry before - create one
entry= cache.addEntry(file.getFullPath(), newDescription, getTimestamp(info));
else {
// just update the existing entry
entry.setTimestamp(info.getContentId());
entry.setCached(newDescription);
}
return newDescription;
}
}
/**
* Returns a timestamp that uniquely identifies a particular content state of a particular
* resource. For use as a key in a content type cache.
*/
private long getTimestamp(ResourceInfo info) {
return info.getContentId() + info.getNodeId();
}
/**
* Marks the cache as invalid. Does not do anything if the cache is new. Optionally causes the
* cached information to be actually flushed.
*
* @param flush whether the cached information should be flushed
* @see #doFlushCache(IProgressMonitor, IPath[])
*/
public synchronized void invalidateCache(boolean flush, IProject project) {
if (getCacheState() == EMPTY_CACHE)
// cache has not been touched, nothing to do
return;
// mark the cache as invalid
try {
setCacheState(INVALID_CACHE);
} catch (CoreException e) {
Policy.log(e.getStatus());
}
if (Policy.DEBUG_CONTENT_TYPE_CACHE)
Policy.debug("Invalidated cache for " + (project == null ? Path.ROOT : project.getFullPath())); //$NON-NLS-1$
if (flush) {
try {
// discard the cache, so it can be used before the flush job starts
setCacheState(ABOUT_TO_FLUSH);
cache.discardAll();
} catch (CoreException e) {
Policy.log(e.getStatus());
}
// the cache is not good, flush it
flushJob.flush(project);
}
}
/**
* Tries to obtain a content description for the given file.
*/
private IContentDescription readDescription(File file) throws CoreException {
if (Policy.DEBUG_CONTENT_TYPE)
Policy.debug("reading contents of " + file); //$NON-NLS-1$
// tries to obtain a description for this file contents
InputStream contents= new LazyFileInputStream(file.getStore());
try {
IContentTypeMatcher matcher= getContentTypeMatcher((Project)file.getProject());
return matcher.getDescriptionFor(contents, file.getName(), IContentDescription.ALL);
} catch (IOException e) {
String message= NLS.bind(Messages.resources_errorContentDescription, file.getFullPath());
throw new ResourceException(IResourceStatus.FAILED_DESCRIBING_CONTENTS, file.getFullPath(), message, e);
} finally {
FileUtil.safeClose(contents);
}
}
/**
* @see IRegistryChangeListener#registryChanged(IRegistryChangeEvent)
*/
public void registryChanged(IRegistryChangeEvent event) {
// no changes related to the content type registry
if (event.getExtensionDeltas(Platform.PI_RUNTIME, PT_CONTENTTYPES).length == 0)
return;
invalidateCache(true, null);
}
/**
* @see ILifecycleListener#handleEvent(LifecycleEvent)
*/
public void handleEvent(LifecycleEvent event) {
//TODO are these the only events we care about?
switch (event.kind) {
case LifecycleEvent.PRE_PROJECT_CHANGE:
// if the project changes, its natures may have changed as well (content types may be associated to natures)
case LifecycleEvent.PRE_PROJECT_DELETE:
// if the project gets deleted, we may get confused if it is recreated again (content ids might match)
case LifecycleEvent.PRE_PROJECT_MOVE:
// if the project moves, resource paths (used as keys in the in-memory cache) will have changed
invalidateCache(true, (IProject)event.resource);
}
}
synchronized void setCacheState(byte newCacheState) throws CoreException {
if (cacheState == newCacheState)
return;
workspace.getRoot().setPersistentProperty(CACHE_STATE, Byte.toString(newCacheState));
cacheState= newCacheState;
}
private void setCacheTimeStamp(long timeStamp) throws CoreException {
workspace.getRoot().setPersistentProperty(CACHE_TIMESTAMP, Long.toString(timeStamp));
}
public void shutdown(IProgressMonitor monitor) throws CoreException {
if (getCacheState() != INVALID_CACHE)
// remember the platform timestamp for which we have a valid cache
setCacheTimeStamp(Platform.getStateStamp());
Platform.getContentTypeManager().removeContentTypeChangeListener(this);
Platform.getExtensionRegistry().removeRegistryChangeListener(this);
cache.dispose();
cache= null;
flushJob.cancel();
flushJob= null;
projectContentTypes= null;
}
public void startup(IProgressMonitor monitor) throws CoreException {
workspace= (Workspace)ResourcesPlugin.getWorkspace();
cache= new Cache(100, 1000, 0.1);
projectContentTypes= new ProjectContentTypes(workspace);
getCacheState();
if (cacheState == FLUSHING_CACHE || cacheState == ABOUT_TO_FLUSH)
// in case we died before completing the last flushing
setCacheState(INVALID_CACHE);
flushJob= new FlushJob();
// the cache is stale (plug-ins that might be contributing content types were added/removed)
if (getCacheTimestamp() != Platform.getStateStamp())
invalidateCache(false, null);
// register a lifecycle listener
workspace.addLifecycleListener(this);
// register a content type change listener
Platform.getContentTypeManager().addContentTypeChangeListener(this);
// register a registry change listener
Platform.getExtensionRegistry().addRegistryChangeListener(this, Platform.PI_RUNTIME);
}
public void projectPreferencesChanged(IProject project) {
if (Policy.DEBUG_CONTENT_TYPE)
Policy.debug("Project preferences changed for " + project); //$NON-NLS-1$
projectContentTypes.contentTypePreferencesChanged(project);
}
}