/*******************************************************************************
* Copyright (c) 2016 Red Hat Inc. 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:
* - Mickael Istria (Red Hat Inc.)
*******************************************************************************/
package org.eclipse.ui.internal.genericeditor;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.eclipse.core.filebuffers.FileBuffers;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IRegistryChangeEvent;
import org.eclipse.core.runtime.IRegistryChangeListener;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.content.IContentType;
import org.eclipse.core.runtime.content.IContentTypeManager;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.contentassist.ICompletionProposal;
import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.text.contentassist.IContextInformationValidator;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.ui.PlatformUI;
/**
* A registry of content assist processors provided by extension <code>org.eclipse.ui.genericeditor.contentAssistProcessors</code>.
* Those extensions are specific to a given {@link IContentType}.
*
* @since 1.0
*/
public class ContentAssistProcessorRegistry {
private static final String EXTENSION_POINT_ID = GenericEditorPlugin.BUNDLE_ID + ".contentAssistProcessors"; //$NON-NLS-1$
/**
* This class wraps and proxies an {@link IContentAssistProcessor} provided through extensions
* and loads it lazily when it can contribute to the editor, then delegates all operations to
* actual processor.
* When the contribution cannot contribute to the editor, this wrapper will return neutral values
* that don't affect editor behavior.
*/
private static class ContentAssistProcessorExtension implements IContentAssistProcessor {
private static final String CONTENT_TYPE_ATTRIBUTE = "contentType"; //$NON-NLS-1$
private static final String CLASS_ATTRIBUTE = "class"; //$NON-NLS-1$
private IConfigurationElement extension;
private IContentType targetContentType;
private IContentAssistProcessor delegate;
private ContentAssistProcessorExtension(IConfigurationElement element) throws Exception {
this.extension = element;
this.targetContentType = Platform.getContentTypeManager().getContentType(element.getAttribute(CONTENT_TYPE_ATTRIBUTE));
}
private IContentAssistProcessor getDelegate() {
if (this.delegate == null) {
try {
this.delegate = (IContentAssistProcessor) extension.createExecutableExtension(CLASS_ATTRIBUTE);
} catch (CoreException e) {
e.printStackTrace();
}
}
return delegate;
}
/**
* @return whether the referenced contribution should contribute to the current editor.
*/
public boolean isActive(ITextViewer viewer) {
String fileName = null;
if (viewer != null && viewer.getDocument() != null) {
IPath location = FileBuffers.getTextFileBufferManager().getTextFileBuffer(viewer.getDocument()).getLocation();
fileName = location.segment(location.segmentCount() - 1);
}
if (fileName == null) {
fileName = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getActiveEditor().getEditorInput().getName();
}
if (fileName != null) {
IContentTypeManager contentTypeManager= Platform.getContentTypeManager();
for (IContentType currentContentType : contentTypeManager.findContentTypesFor(fileName)) {
if (currentContentType.isKindOf(targetContentType)) {
return true;
}
}
}
return false;
}
@Override
public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int offset) {
if (isActive(viewer)) {
return getDelegate().computeCompletionProposals(viewer, offset);
}
return new ICompletionProposal[0];
}
@Override
public IContextInformation[] computeContextInformation(ITextViewer viewer, int offset) {
if (isActive(viewer)) {
return getDelegate().computeContextInformation(viewer, offset);
}
return new IContextInformation[0];
}
@Override
public char[] getCompletionProposalAutoActivationCharacters() {
if (isActive(null)) {
return getDelegate().getCompletionProposalAutoActivationCharacters();
}
return null;
}
@Override
public char[] getContextInformationAutoActivationCharacters() {
if (isActive(null)) {
return getDelegate().getContextInformationAutoActivationCharacters();
}
return null;
}
@Override
public String getErrorMessage() {
if (isActive(null)) {
return getDelegate().getErrorMessage();
}
return null;
}
@Override
public IContextInformationValidator getContextInformationValidator() {
if (isActive(null)) {
return getDelegate().getContextInformationValidator();
}
return null;
}
}
private Map<IConfigurationElement, ContentAssistProcessorExtension> extensions = new HashMap<>();
private boolean outOfSync = true;
/**
* Creates the registry and binds it to the extension point.
*/
public ContentAssistProcessorRegistry() {
Platform.getExtensionRegistry().addRegistryChangeListener(new IRegistryChangeListener() {
@Override
public void registryChanged(IRegistryChangeEvent event) {
outOfSync = true;
}
}, EXTENSION_POINT_ID);
}
/**
* Get the contributed {@link IContentAssistProcessor}s that are relevant to hook on source viewer according
* to document content types.
* @param sourceViewer the source viewer we're hooking completion to.
* @param contentTypes the content types of the document we're editing.
* @return the list of {@link IContentAssistProcessor} contributed for at least one of the content types.
*/
public List<IContentAssistProcessor> getContentAssistProcessors(ISourceViewer sourceViewer, Set<IContentType> contentTypes) {
if (this.outOfSync) {
sync();
}
List<IContentAssistProcessor> res = new ArrayList<>();
for (ContentAssistProcessorExtension ext : this.extensions.values()) {
if (contentTypes.contains(ext.targetContentType)) {
res.add(ext);
}
}
return res;
}
private void sync() {
Set<IConfigurationElement> toRemoveExtensions = new HashSet<>(this.extensions.keySet());
for (IConfigurationElement extension : Platform.getExtensionRegistry().getConfigurationElementsFor(EXTENSION_POINT_ID)) {
toRemoveExtensions.remove(extension);
if (!this.extensions.containsKey(extension)) {
try {
this.extensions.put(extension, new ContentAssistProcessorExtension(extension));
} catch (Exception ex) {
GenericEditorPlugin.getDefault().getLog().log(new Status(IStatus.ERROR, GenericEditorPlugin.BUNDLE_ID, ex.getMessage(), ex));
}
}
}
for (IConfigurationElement toRemove : toRemoveExtensions) {
this.extensions.remove(toRemove);
}
this.outOfSync = false;
}
}