path: root/org.eclipse.core.filebuffers/src/org/eclipse/core/internal/filebuffers/ExtensionsRegistry.java

/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.filebuffers;



import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.ILog;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.content.IContentDescription;
import org.eclipse.core.runtime.content.IContentType;
import org.eclipse.core.runtime.content.IContentTypeManager;

import org.eclipse.core.filebuffers.FileBuffers;
import org.eclipse.core.filebuffers.IAnnotationModelFactory;
import org.eclipse.core.filebuffers.IDocumentFactory;
import org.eclipse.core.filebuffers.IDocumentSetupParticipant;

import org.eclipse.jface.text.Assert;


/**
 * This registry manages sharable document factories. Document factories are specified 
 * in <code>plugin.xml</code> per file name extension.
 */
public class ExtensionsRegistry {
	
	/**
	 * Adapts IContentType with the ability to check
	 * equality. This allows to use them in a collection.
	 */
	private static class ContentTypeAdapter {
		
		/** The adapted content type. */
		private IContentType fContentType;

		/**
		 * Creates a new content type adapter for the
		 * given content type.
		 * 
		 * @param contentType the content type to be adapted
		 */
		public ContentTypeAdapter(IContentType  contentType) {
			Assert.isNotNull(contentType);
			fContentType= contentType;
		}
		
		/**
		 * Return the adapted content type.
		 * 
		 * @return the content type
		 */
		public IContentType getContentType() {
			return fContentType;
		}

		/**
		 * Return the Id of the adapted content type.
		 * 
		 * @return the Id
		 */
		public String getId() {
			return fContentType.getId();
		}

		/*
		 * @see java.lang.Object#equals(java.lang.Object)
		 */
		public boolean equals(Object obj) {
			return obj instanceof ContentTypeAdapter && fContentType.getId().equals(((ContentTypeAdapter)obj).getId());
		}
		
		/*
		 * @see java.lang.Object#hashCode()
		 */
		public int hashCode() {
			return fContentType.getId().hashCode();
		}
	}
	
	private final static String WILDCARD= "*";  //$NON-NLS-1$
	
	/** The mapping between file attributes and configuration elements describing document factories. */
	private Map fFactoryDescriptors= new HashMap();
	/** The mapping between configuration elements for document factories and instantiated document factories. */
	private Map fFactories= new HashMap();
	/** The mapping between file attributes and configuration elements describing document setup participants. */
	private Map fSetupParticipantDescriptors= new HashMap();
	/** The mapping between configuration elements for setup participants and instantiated setup participants. */
	private Map fSetupParticipants= new HashMap();
	/** The mapping between file attributes and configuration elements describing annotation model factories. */
	private Map fAnnotationModelFactoryDescriptors= new HashMap();
	/** The mapping between configuration elements for annotation model factories */
	private Map fAnnotationModelFactories= new HashMap();
	/** The content type manager. */
	private IContentTypeManager fContentTypeManager= Platform.getContentTypeManager();
	
	
	/**
	 * Creates a new document factory registry and initializes it with the information
	 * found in the plug-in registry.
	 */
	public ExtensionsRegistry() {
		initialize("documentCreation", "contentTypeId", true,  fFactoryDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("documentCreation", "fileNames", false, fFactoryDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("documentCreation", "extensions",  false, fFactoryDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("documentSetup", "contentTypeId", true, fSetupParticipantDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("documentSetup", "fileNames", false, fSetupParticipantDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("documentSetup", "extensions", false, fSetupParticipantDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("annotationModelCreation", "contentTypeId", true, fAnnotationModelFactoryDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("annotationModelCreation", "fileNames", false, fAnnotationModelFactoryDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		initialize("annotationModelCreation", "extensions", false, fAnnotationModelFactoryDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
		
	}
	
	/**
	 * Reads the comma-separated value from the given configuration element for the given attribute name and remembers
	 * the configuration element in the given map under the individual tokens of the attribute value.
	 * 
	 * @param attributeName the name of the attribute
	 * @param element the configuration element
	 * @param map the map which remembers the configuration element 
	 */
	private void read(String attributeName, IConfigurationElement element, Map map) {
		String value= element.getAttribute(attributeName);
		if (value != null) {
			StringTokenizer tokenizer= new StringTokenizer(value, ","); //$NON-NLS-1$
			while (tokenizer.hasMoreTokens()) {
				String token= tokenizer.nextToken().trim();
				
				Set s= (Set) map.get(token);
				if (s == null) {
					s= new HashSet();
					map.put(token, s);
				}
				s.add(element);
			}
		}
	}
	
	/**
	 * Reads the value from the given configuration element for the given attribute name and remembers
	 * the configuration element in the given map under the individual content type of the attribute value.
	 * 
	 * @param attributeName the name of the attribute
	 * @param element the configuration element
	 * @param map the map which remembers the configuration element 
	 */
	private void readContentType(String attributeName, IConfigurationElement element, Map map) {
		String value= element.getAttribute(attributeName);
		if (value != null) {
			IContentType contentType= fContentTypeManager.getContentType(value);
			if (contentType == null) {
				log(new Status(IStatus.ERROR, FileBuffersPlugin.PLUGIN_ID, 0, FileBuffersMessages.getFormattedString("ExtensionsRegistry.error.contentTypeDoesNotExist", new Object[] { value }), null)); //$NON-NLS-1$
				return;
			}
			ContentTypeAdapter adapter= new ContentTypeAdapter(contentType);
			Set s= (Set) map.get(adapter);
			if (s == null) {
				s= new HashSet();
				map.put(adapter, s);
			}
			s.add(element);
		}
	}
	
	/**
	 * Adds an entry to the log of this plug-in for the given status
	 * @param status the status to log
	 */
	private void log(IStatus status) {
		ILog log= FileBuffersPlugin.getDefault().getLog();
		log.log(status);
	}
	
	/**
	 * Initializes this registry. It retrieves all implementers of the given
	 * extension point and remembers those implementers based on the
	 * file name extensions in the given map.
	 * 
	 * @param extensionPointName the name of the extension point
	 * @param childElementName the name of the child elements
	 * @param isContentTypeId the child element is a content type id
	 * @param descriptors the map to be filled 
	 */
	private void initialize(String extensionPointName, String childElementName, boolean isContentTypeId, Map descriptors) {
		
		IExtensionPoint extensionPoint= Platform.getExtensionRegistry().getExtensionPoint(FileBuffersPlugin.PLUGIN_ID, extensionPointName);
		if (extensionPoint == null) {
			log(new Status(IStatus.ERROR, FileBuffersPlugin.PLUGIN_ID, 0, FileBuffersMessages.getFormattedString("ExtensionsRegistry.error.extensionPointNotFound", new Object[] { extensionPointName}), null)); //$NON-NLS-1$
			return;
		}
		
		IConfigurationElement[] elements= extensionPoint.getConfigurationElements();
		for (int i= 0; i < elements.length; i++) {
			if (isContentTypeId)
				readContentType(childElementName, elements[i], descriptors);
			else
				read(childElementName, elements[i], descriptors);
		}
	}
	
	/**
	 * Returns the executable extension for the given configuration element.
	 * If there is no instantiated extension remembered for this
	 * element, a new extension is created and put into the cache if it is of the requested type.
	 * 
	 * @param entry the configuration element
	 * @param extensions the map of instantiated extensions
	 * @param extensionType the requested result type
	 * @return the executable extension for the given configuration element.
	 */
	private Object getExtension(IConfigurationElement entry, Map extensions, Class extensionType) {
		Object extension= extensions.get(entry);
		if (extension != null)
			return extension;
			
		try {
			extension= entry.createExecutableExtension("class"); //$NON-NLS-1$
		} catch (CoreException x) {
			log(x.getStatus());
		}
		
		if (extensionType.isInstance(extension)) {
			extensions.put(entry, extension);
			return extension;
		}
		
		return null;
	}
	
	/**
	 * Returns the first enumerated element of the given set.
	 * 
	 * @param set the set from which to choose
	 * @return the selected configuration element
	 */
	private IConfigurationElement selectConfigurationElement(Set set) {
		if (set != null && !set.isEmpty()) {
			Iterator e= set.iterator();
			return (IConfigurationElement) e.next();
		}
		return null;
	}

	/**
	 * Returns a sharable document factory for the given file name or file extension.
	 *
	 * @param nameOrExtension the name or extension to be used for lookup
	 * @return the sharable document factory or <code>null</code>
	 */
	private IDocumentFactory getDocumentFactory(String nameOrExtension) {
		Set set= (Set) fFactoryDescriptors.get(nameOrExtension);
		if (set != null) {
			IConfigurationElement entry= selectConfigurationElement(set);
			return (IDocumentFactory) getExtension(entry, fFactories, IDocumentFactory.class);
		}
		return null;
	}
	
	/**
	 * Returns a sharable document factory for the given content types.
	 *
	 * @param contentTypes the content types used to find the factory
	 * @return the sharable document factory or <code>null</code>
	 */
	private IDocumentFactory getDocumentFactory(IContentType[] contentTypes) {
		Set set= null;
		int i= 0;
		while (i < contentTypes.length && set == null) {
			set= (Set) fFactoryDescriptors.get(new ContentTypeAdapter(contentTypes[i++]));
		}

		if (set != null) {
			IConfigurationElement entry= selectConfigurationElement(set);
			return (IDocumentFactory) getExtension(entry, fFactories, IDocumentFactory.class);
		}
		return null;
	}
	
	/**
	 * Returns the set of setup participants for the given file name or extension.
	 * 
	 * @param nameOrExtension the name or extension to be used for lookup
	 * @return the sharable set of document setup participants
	 */
	private List getDocumentSetupParticipants(String nameOrExtension) {
		Set set= (Set) fSetupParticipantDescriptors.get(nameOrExtension);
		if (set == null)
			return null;
		
		List participants= new ArrayList();
		Iterator e= set.iterator();
		while (e.hasNext()) {
			IConfigurationElement entry= (IConfigurationElement) e.next();
			Object participant= getExtension(entry, fSetupParticipants, IDocumentSetupParticipant.class);
			if (participant != null)
				participants.add(participant);
		}
		
		return participants;
	}
	
	/**
	 * Returns the set of setup participants for the given content types.
	 * 
	 * @param contentTypes the contentTypes to be used for lookup
	 * @return the sharable set of document setup participants
	 */
	private List getDocumentSetupParticipants(IContentType[] contentTypes) {
		Set resultSet= new HashSet();
		int i= 0;
		while (i < contentTypes.length) {
			Set set= (Set) fFactoryDescriptors.get(new ContentTypeAdapter(contentTypes[i++]));
			if (set != null)
				resultSet.addAll(set);
		}
		
		List participants= new ArrayList();
		Iterator e= resultSet.iterator();
		while (e.hasNext()) {
			IConfigurationElement entry= (IConfigurationElement) e.next();
			Object participant= getExtension(entry, fSetupParticipants, IDocumentSetupParticipant.class);
			if (participant != null)
				participants.add(participant);
		}
		
		return participants;
	}
	
	/**
	 * Returns a sharable annotation model factory for the given content types.
	 *
	 * @param contentTypes the content types used to find the factory
	 * @return the sharable annotation model factory or <code>null</code>
	 */
	private IAnnotationModelFactory getAnnotationModelFactory(IContentType[] contentTypes) {
		Set set= null;
		int i= 0;
		while (i < contentTypes.length && set == null) {
			set= (Set) fAnnotationModelFactoryDescriptors.get(new ContentTypeAdapter(contentTypes[i++]));
		}

		if (set != null) {
			IConfigurationElement entry= selectConfigurationElement(set);
			return (IAnnotationModelFactory) getExtension(entry, fAnnotationModelFactories, IAnnotationModelFactory.class);
		}
		return null;
	}
	
	/**
	 * Returns a sharable annotation model factory for the given file name or file extension.
	 *
	 * @param extension the name or extension to be used for lookup
	 * @return the sharable document factory or <code>null</code>
	 */
	private IAnnotationModelFactory getAnnotationModelFactory(String extension) {
		Set set= (Set) fAnnotationModelFactoryDescriptors.get(extension);
		if (set != null) {
			IConfigurationElement entry= selectConfigurationElement(set);
			return (IAnnotationModelFactory) getExtension(entry, fAnnotationModelFactories, IAnnotationModelFactory.class);
		}
		return null;
	}
	
	private IContentType[] findContentTypes(IPath path) {
		IFile file= FileBuffers.getWorkspaceFileAtLocation(path);
		if (file == null)
			return new IContentType[0];
		
		IContentDescription contentDescription;
		try {
			contentDescription= file.getContentDescription();
		} catch (CoreException ex) {
			contentDescription= null;
		}
		
		if (contentDescription != null) {
			IContentType contentType= contentDescription.getContentType();
			if (contentType != null)
				return new IContentType[] {contentType};
		}
		
		return fContentTypeManager.findContentTypesFor(path.lastSegment());
	}
	
	/**
	 * Returns the sharable document factory for the given location.
	 *
	 * @param location the location for which to looked up the factory
	 * @return the sharable document factory
	 */
	public IDocumentFactory getDocumentFactory(IPath location) {
		IDocumentFactory factory= getDocumentFactory(findContentTypes(location));
		if (factory == null)
			factory= getDocumentFactory(location.lastSegment());
		if (factory == null)
			factory= getDocumentFactory(location.getFileExtension());
		if (factory == null)
			factory= getDocumentFactory(WILDCARD);
		return factory;
	}
	
	/**
	 * Returns the sharable set of document setup participants for the given location.
	 * 
	 * @param location the location for which to look up the setup participants
	 * @return the sharable set of document setup participants
	 */
	public IDocumentSetupParticipant[] getDocumentSetupParticipants(IPath location) {
		List participants= new ArrayList();
		
		List p= getDocumentSetupParticipants(findContentTypes(location));
		if (p != null)
			participants.addAll(p);
		
		p= getDocumentSetupParticipants(location.lastSegment());
		if (p != null)
			participants.addAll(p);
		
		p= getDocumentSetupParticipants(location.getFileExtension());
		if (p != null)
			participants.addAll(p);
			
		p= getDocumentSetupParticipants(WILDCARD);
		if (p != null)
			participants.addAll(p);
			
		IDocumentSetupParticipant[] result= new IDocumentSetupParticipant[participants.size()];
		participants.toArray(result);
		return result;
	}
	
	/**
	 * Returns the sharable annotation model factory for the given location.
	 * 
	 * @param location the location for which to look up the factory
	 * @return the sharable annotation model factory
	 */
	public IAnnotationModelFactory getAnnotationModelFactory(IPath location) {
		IAnnotationModelFactory factory= getAnnotationModelFactory(findContentTypes(location));
		if (factory == null)
			factory= getAnnotationModelFactory(location.lastSegment());
		if (factory == null)
			factory= getAnnotationModelFactory(location.getFileExtension());
		if (factory == null)
			factory= getAnnotationModelFactory(WILDCARD);
		return factory;
	}
}