r/org.eclipse.statet.r.core/src/org/eclipse/statet/internal/r/core/rhelp/RHelpManager.java - statet/org.eclipse.statet-r - Git at Google

 /*=============================================================================#
  # Copyright (c) 2010, 2017 Stephan Wahlbrink and others.
  #
  # This program and the accompanying materials are made available under the
  # terms of the Eclipse Public License 2.0 which is available at
  # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
  # which is available at https://www.apache.org/licenses/LICENSE-2.0.
  #
  # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
  #
  # Contributors:
  #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
  #=============================================================================*/

 package org.eclipse.statet.internal.r.core.rhelp;

 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.jobs.Job;

 import org.eclipse.statet.jcommons.collections.ImCollections;
 import org.eclipse.statet.jcommons.collections.ImIdentitySet;
 import org.eclipse.statet.jcommons.lang.Disposable;

 import org.eclipse.statet.ecommons.preferences.core.PreferenceAccess;
 import org.eclipse.statet.ecommons.preferences.core.PreferenceSetService;
 import org.eclipse.statet.ecommons.preferences.core.PreferenceSetService.ChangeEvent;
 import org.eclipse.statet.ecommons.preferences.core.util.PreferenceUtils;

 import org.eclipse.statet.internal.r.core.RCorePlugin;
 import org.eclipse.statet.internal.r.core.renv.REnvConfiguration;
 import org.eclipse.statet.internal.r.core.renv.REnvManager;
 import org.eclipse.statet.internal.r.core.rhelp.RHelpWebapp.ContentInfo;
 import org.eclipse.statet.r.core.RCore;
 import org.eclipse.statet.r.core.renv.IREnv;
 import org.eclipse.statet.r.core.renv.IREnvConfiguration;
 import org.eclipse.statet.r.core.renv.IREnvManager;
 import org.eclipse.statet.r.core.rhelp.IRHelpManager;
 import org.eclipse.statet.r.core.rhelp.IRHelpPage;
 import org.eclipse.statet.r.core.rhelp.IRHelpSearchRequestor;
 import org.eclipse.statet.r.core.rhelp.IRPkgHelp;
 import org.eclipse.statet.r.core.rhelp.RHelpSearchQuery;


 public class RHelpManager implements IRHelpManager, PreferenceSetService.ChangeListener, Disposable {
 // Compatible to dynamic R help
 // 1) With dynamic= TRUE from tools:::httpd()
 //    Here generated links are of the forms
 //    ../../pkg/help/topic
 //    file.html
 //    ../../pkg/html/file.html
 //    and links are never missing: topics are always linked as
 //    ../../pkg/help/topic for the current packages, and this means
 //    'search this package then all the others, and show all matches
 //    if we need to go outside this packages'


 	private static final ImIdentitySet<String> PREF_QUALIFIERS= ImCollections.newIdentitySet(
 			IREnvManager.PREF_QUALIFIER );


 	private static class EnvItem {

 		final String id;

 		int state;

 		REnvHelp help;
 		String indexDir;

 		final Object helpLock= new Object();
 		final Object indexLock= new Object();

 		public EnvItem(final String id) {
 			this.id= id;
 			this.state= 0;
 			this.help= null;
 			this.indexDir= null;
 		}

 	}

 	private class InitJob extends Job {

 		public InitJob() {
 			super("Prepare R help");
 			setSystem(true);
 			setPriority(Job.DECORATE);
 		}

 		@Override
 		protected IStatus run(final IProgressMonitor monitor) {
 			ensureIsRunning();

 			final IREnv rEnv= RHelpManager.this.rEnvManager.getDefault().resolve();
 			if (rEnv != null) {
 				final REnvHelp help= getHelp(rEnv);
 				if (help != null) {
 					help.unlock();
 				}
 			}

 			return Status.OK_STATUS;
 		}

 	}

 	private static final int HELP_LOADED= 1;
 	private static final int HELP_MISSING= -1;
 	private static final int RENV_DELETED= -2;

 	/**
 	 * Searches topic in library
 	 */
 	private static final String RHELP_TOPIC_PATH= "/topic"; //$NON-NLS-1$

 	/**
 	 * Shows page (package, package/name or package/topic)
 	 */
 	private static final String RHELP_PAGE_PATH= "/page"; //$NON-NLS-1$


 	private final PreferenceAccess prefAccess;

 	private final REnvManager rEnvManager= RCorePlugin.getInstance().getREnvManager();
 	private boolean running;

 	private boolean httpdStarted;
 	private JettyServer httpd;

 	private final Object indexLock= new Object();

 	private final SaveUtil saveUtil= new SaveUtil();

 	private final Map<String, EnvItem> helpIndexes= new HashMap<>();


 	public RHelpManager() {
 		this.prefAccess= PreferenceUtils.getInstancePrefs();
 		this.prefAccess.addPreferenceSetListener(this, PREF_QUALIFIERS);
 		new InitJob().schedule(1000);
 	}


 	@Override
 	public String getPageHttpUrl(final IRHelpPage page, final String target) {
 		final IRPkgHelp pkgHelp= page.getPackage();
 		return getPageHttpUrl(pkgHelp.getName(), page.getName(), pkgHelp.getREnv(), target);
 	}

 	@Override
 	public String getPageHttpUrl(final String packageName, final String pageName,
 			final IREnv rEnv, final String target) {
 		checkRunning();
 		final StringBuilder sb= new StringBuilder(64);
 		sb.append(RHelpWebapp.CONTEXT_PATH);
 		sb.append('/');
 		sb.append(target);
 		sb.append('/');
 		sb.append(rEnv.getId());
 		sb.append('/');
 		sb.append(RHelpWebapp.CAT_LIBRARY);
 		sb.append('/');
 		sb.append(packageName);
 		sb.append('/');
 		if (pageName != null) {
 			sb.append(RHelpWebapp.COMMAND_HTML_PAGE);
 			sb.append('/');
 			sb.append(pageName);
 			sb.append(".html"); //$NON-NLS-1$
 		}
 		return createUrl(sb.toString());
 	}

 	@Override
 	public String getTopicHttpUrl(final String topic, final String packageName,
 			final IREnv rEnv, final String target) {
 		checkRunning();
 		final StringBuilder sb= new StringBuilder(64);
 		sb.append(RHelpWebapp.CONTEXT_PATH);
 		sb.append('/');
 		sb.append(target);
 		sb.append('/');
 		sb.append(rEnv.getId());
 		sb.append('/');
 		sb.append(RHelpWebapp.CAT_LIBRARY);
 		sb.append('/');
 		sb.append(packageName);
 		sb.append('/');
 		sb.append(RHelpWebapp.COMMAND_HELP_TOPIC);
 		sb.append('/');
 		sb.append(topic);
 		return createUrl(sb.toString());
 	}

 	@Override
 	public String getREnvHttpUrl(final IREnv rEnv, final String target) {
 		checkRunning();
 		final StringBuilder sb= new StringBuilder(64);
 		sb.append(RHelpWebapp.CONTEXT_PATH);
 		sb.append('/');
 		sb.append(target);
 		sb.append('/');
 		sb.append(rEnv.getId());
 		sb.append('/');
 		return createUrl(sb.toString());
 	}

 	@Override
 	public String getPackageHttpUrl(final IRPkgHelp pkgHelp, final String target) {
 		return getPageHttpUrl(pkgHelp.getName(), null, pkgHelp.getREnv(), target);
 	}

 	@Override
 	public String toHttpUrl(final String url, final IREnv rEnv, final String target) {
 		checkRunning();
 		if (url.startsWith("rhelp:///")) { //$NON-NLS-1$
 			final StringBuilder sb= new StringBuilder(64);
 			sb.append(RHelpWebapp.CONTEXT_PATH);
 			sb.append('/');
 			sb.append(target);

 			final String path= url.substring(8);
 			final int idx1= (path.length() > 0) ? path.indexOf('/', 1) : -1;
 			if (idx1 > 0) {
 				final String command= path.substring(0, idx1);
 				if (command.equals(RHELP_PAGE_PATH)) {
 					sb.append('/');
 					sb.append(rEnv.getId());
 					sb.append('/');
 					sb.append(RHelpWebapp.CAT_LIBRARY);
 					final int idx2= path.indexOf('/', idx1 + 1);
 					if (idx2 > idx1 + 1 && idx2 < path.length() - 1) {
 						sb.append('/');
 						sb.append(path.substring(idx1 + 1, idx2));
 						sb.append('/');
 						sb.append(RHelpWebapp.COMMAND_HTML_PAGE);
 						sb.append('/');
 						sb.append(path.substring(idx2 + 1));
 						sb.append(".html"); //$NON-NLS-1$
 					}
 					else {
 						sb.append('/');
 						sb.append(path.substring(idx1 + 1, (idx2 > 0) ? idx2 : path.length()));
 						sb.append('/');
 					}
 					return createUrl(sb.toString());
 				}
 				else if (command.equals(RHELP_TOPIC_PATH)) {
 					sb.append('/');
 					sb.append(rEnv.getId());
 					sb.append('/');
 					sb.append(RHelpWebapp.CAT_LIBRARY);
 					sb.append('/');
 					sb.append('-');
 					sb.append('/');
 					sb.append(RHelpWebapp.COMMAND_HELP_TOPIC);
 					sb.append('/');
 					sb.append(path.substring(idx1 + 1));
 					return createUrl(sb.toString());
 				}
 			}
 			else if (path.length() == 1) { // start
 				sb.append('/');
 				sb.append(rEnv.getId());
 				sb.append('/');
 				return createUrl(sb.toString());
 			}
 			return null;
 		}
 		if (url.startsWith("http://") && (rEnv != null || target != null)) { //$NON-NLS-1$
 			try {
 				final URI uri= new URI(url);
 				if (isDynamic(uri)) {
 					final String path= uri.getPath();
 					if (path != null && path.startsWith(RHelpWebapp.CONTEXT_PATH)) {
 						final int idx2= path.indexOf('/', RHelpWebapp.CONTEXT_PATH.length() + 1);
 						if (idx2 >= 0) {
 							final StringBuilder sb= new StringBuilder(path.length() + 16);
 							sb.append(RHelpWebapp.CONTEXT_PATH);
 							sb.append('/');
 							sb.append((target != null) ? target :
 									path.substring(RHelpWebapp.CONTEXT_PATH.length() + 1, idx2));
 							final String info= path.substring(idx2 + 1);
 							if (rEnv != null) {
 								final int idx3= info.indexOf('/');
 								if (idx3 < 0) {
 									return null;
 								}
 								sb.append('/');
 								sb.append(rEnv.getId());
 								sb.append(info.substring(idx3));
 							}
 							else {
 								sb.append('/');
 								sb.append(info);
 							}
 							return new URI(uri.getScheme(), uri.getUserInfo(), uri.getHost(), uri.getPort(),
 									sb.toString(), uri.getQuery(), uri.getFragment()).toString();
 						}
 					}
 					return null;
 				}
 			}
 			catch (final Exception e) {}
 		}
 		return url;
 	}

 	@Override
 	public String toHttpUrl(final Object object, final String target) {
 		if (object == this) {
 			return "about:blank"; //$NON-NLS-1$
 		}
 		if (object instanceof IREnv) {
 			return getREnvHttpUrl((IREnv) object, target);
 		}
 		if (object instanceof IREnvConfiguration) {
 			return getREnvHttpUrl(((IREnvConfiguration) object).getReference(), target);
 		}
 		if (object instanceof IRPkgHelp) {
 			return getPackageHttpUrl((IRPkgHelp) object, target);
 		}
 		if (object instanceof IRHelpPage) {
 			return getPageHttpUrl((IRHelpPage) object, target);
 		}
 		if (object instanceof String) {
 			final String s= (String) object;
 			if (s.startsWith("http://")) { //$NON-NLS-1$
 				return s;
 			}
 		}
 		return null;
 	}

 	private String createUrl(final String path) {
 		try {
 			return new URI("http", null, this.httpd.getHost(), this.httpd.getPort(), path, null, null) //$NON-NLS-1$
 					.toASCIIString();
 		}
 		catch (final URISyntaxException e) {
 			throw new IllegalStateException(e);
 		}
 	}

 	@Override
 	public Object getContentOfUrl(final String url) {
 		try {
 			final URI uri= new URI(url);
 			final String path= uri.getPath();
 			if (uri.getScheme() != null && uri.getScheme().equals("http") //$NON-NLS-1$
 					&& path != null && path.startsWith(RHelpWebapp.CONTEXT_PATH)) {
 				final int idx2= path.indexOf('/', RHelpWebapp.CONTEXT_PATH.length() + 1);
 				if (idx2 >= 0) {
 					final ContentInfo info= RHelpWebapp.extractContent(path.substring(idx2));
 					if (info != null) {
 						final IREnv rEnv= this.rEnvManager.get(info.rEnvId, null);
 						if (rEnv != null && info.cat == RHelpWebapp.CAT_LIBRARY) {
 							final REnvHelp help= getHelp(rEnv);
 							if (help != null) {
 								try {
 									final IRPkgHelp pkgHelp= help.getPkgHelp(info.packageName);
 									if (pkgHelp != null && info.command == RHelpWebapp.COMMAND_HTML_PAGE) {
 										final IRHelpPage page= pkgHelp.getHelpPage(info.detail);
 										if (page != null) {
 											return page;
 										}
 									}
 									return pkgHelp;
 								}
 								finally {
 									help.unlock();
 								}
 							}
 							return null;
 						}
 						if (rEnv != null && info.cat == RHelpWebapp.CAT_DOC) {
 							return new Object[] { rEnv, null };
 						}
 						return rEnv;
 					}
 				}
 			}
 		} catch (final URISyntaxException e) {}
 		return null;
 	}

 	@Override
 	public boolean ensureIsRunning() {
 		if (!this.httpdStarted) {
 			startServer();
 		}
 		return this.running;
 	}

 	@Override
 	public boolean isDynamic(final URI url) {
 		checkRunning();
 		return ((this.httpd.getHost().equals(url.getHost()) && this.httpd.getPort() == url.getPort()
 				|| PORTABLE_URL_SCHEME.equals(url.getScheme()) ));
 	}

 	@Override
 	public URI toHttpUrl(final URI url) throws URISyntaxException {
 		if (isDynamic(url)) {
 			String path= url.getPath();
 			if (path != null && !path.startsWith("/rhelp")) {
 				path= "/rhelp" + path;
 			}
 			return new URI("http", null, this.httpd.getHost(), this.httpd.getPort(),
 					path, url.getQuery(), url.getFragment());
 		}
 		return url;
 	}

 	@Override
 	public URI toPortableUrl(final URI url) throws URISyntaxException {
 		if (isDynamic(url)) {
 			String path= url.getPath();
 			if (path != null && path.startsWith("/rhelp")) {
 				path= path.substring(6);
 			}
 			return new URI(PORTABLE_URL_SCHEME, null, null, -1,
 					path, url.getQuery(), url.getFragment());
 		}
 		return url;
 	}

 	private void checkRunning() {
 		if (!ensureIsRunning()) {
 			throw new UnsupportedOperationException("Help is not available.");
 		}
 	}

 	private synchronized void startServer() {
 		if (this.httpdStarted) {
 			return;
 		}
 		final JettyServer httpd= new JettyServer();
 		try {
 			httpd.startServer();
 			this.httpd= httpd;
 			this.running= true;
 		}
 		catch (final Exception e) {
 			RCorePlugin.log(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
 						"An error occured when starting webserver for R help.", e));
 			try {
 				httpd.stopServer();
 			}
 			catch (final Exception ignore) {}
 		}
 		this.httpdStarted= true;
 	}

 	private synchronized void stopServer() {
 		if (this.httpd == null) {
 			return;
 		}
 		this.running= false;
 		try {
 			this.httpd.stopServer();
 			this.httpd= null;
 		}
 		catch (final Exception e) {
 			RCorePlugin.log(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
 					"An error occured when stopping webserver for R help.", e));
 		}
 	}


 	@Override
 	public void search(final RHelpSearchQuery query, final IRHelpSearchRequestor requestor,
 			final IProgressMonitor monitor) throws CoreException {
 		if (query == null) {
 			throw new NullPointerException("query"); //$NON-NLS-1$
 		}
 		if (requestor == null) {
 			throw new NullPointerException("requestor"); //$NON-NLS-1$
 		}
 		final RHelpSearchQuery.Compiled compiledQuery= query.compile();
 		final REnvHelp help= getHelp(compiledQuery.getREnv());
 		if (help != null) {
 			try {
 				if (!help.search(compiledQuery, requestor)) {
 					throw new CoreException(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
 							"An internal error occurend when performing R help search.", null));
 				}
 			}
 			finally {
 				help.unlock();
 			}
 		}
 		else {
 			final IREnv rEnv= query.getREnv();
 			if (rEnv == null || rEnv.getConfig() == null) {
 				throw new CoreException(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
 						"The selected R environment doesn't exists.", null));
 			}
 			else {
 				throw new CoreException(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
 						"The R library of the selected R environment <code>" + compiledQuery.getREnv().getName() +
 						"</code> is not yet indexed. Please run the indexer first to enable R help support.", null));
 			}
 		}
 	}


 	@Override
 	public void preferenceChanged(final ChangeEvent event) {
 		if (event.contains(IREnvManager.PREF_QUALIFIER)) {
 			final List<IREnvConfiguration> configurations= this.rEnvManager.getConfigurations();
 			final EnvItem[] items= new EnvItem[configurations.size()];
 			synchronized (this.indexLock) {
 				for (int i= 0; i < configurations.size(); i++) {
 					items[i]= this.helpIndexes.get(configurations.get(i).getReference().getId());
 				}
 			}
 			for (int i= 0; i < configurations.size(); i++) {
 				if (items[i] != null) {
 					final EnvItem item= items[i];
 					final IREnvConfiguration config= configurations.get(i);
 					REnvHelp oldHelp= null;
 					synchronized (item.helpLock) {
 						if (!((item.indexDir != null) ?
 								item.indexDir.equals(config.getIndexDirectoryPath()) :
 								null == config.getIndexDirectoryPath() )) {
 							item.state= 0;
 							oldHelp= item.help;
 							item.help= null;
 						}
 					}
 					if (oldHelp != null) {
 						oldHelp.dispose();
 					}
 				}
 			}
 		}
 	}

 	public boolean updateHelp(final IREnvConfiguration rEnvConfig,
 			final Map<String, String> rEnvSharedProperties, final REnvHelp help) {
 		final IREnv rEnv= help.getREnv();
 		final String rEnvId= rEnv.getId();
 		EnvItem item;
 		synchronized (this.indexLock) {
 			item= this.helpIndexes.get(rEnvId);
 			if (item == null) {
 				item= new EnvItem(rEnvId);
 				this.helpIndexes.put(rEnvId, item);
 			}
 		}
 		REnvHelp oldHelp= null;
 		try {
 			synchronized (item.helpLock) {
 				if (item.state == RENV_DELETED) {
 					oldHelp= help;
 					return false;
 				}
 				item.state= HELP_LOADED;
 				item.indexDir= rEnvConfig.getIndexDirectoryPath();
 				oldHelp= item.help;
 				item.help= help;
 				this.saveUtil.save(rEnvConfig, help);
 				if (rEnvConfig instanceof REnvConfiguration) {
 					((REnvConfiguration) rEnvConfig).updateSharedProperties(rEnvSharedProperties);
 				}
 				return true;
 			}
 		}
 		finally {
 			if (oldHelp != null) {
 				oldHelp.dispose();
 			}
 		}
 	}

 	public void delete(final String id) {
 		if (id != null && id.length() > 0) {
 			EnvItem item;
 			synchronized (this.indexLock) {
 				item= this.helpIndexes.get(id);
 				if (item == null) {
 					item= new EnvItem(id);
 					this.helpIndexes.put(id, item);
 				}
 			}
 			REnvHelp oldHelp= null;
 			synchronized (item.helpLock) {
 				item.state= RENV_DELETED;
 				oldHelp= item.help;
 				item.help= null;
 			}
 			if (oldHelp != null) {
 				oldHelp.dispose();
 			}
 		}
 	}

 	@Override
 	public List<IREnv> getREnvWithHelp() {
 		final List<IREnvConfiguration> configurations= this.rEnvManager.getConfigurations();
 		final EnvItem[] items= new EnvItem[configurations.size()];
 		synchronized (this.indexLock) {
 			for (int i= 0; i < configurations.size(); i++) {
 				final String id= configurations.get(i).getReference().getId();
 				EnvItem item= this.helpIndexes.get(id);
 				if (item == null) {
 					item= new EnvItem(id);
 					this.helpIndexes.put(id, item);
 				}
 				items[i]= item;
 			}
 		}
 		final List<IREnv> withHelp= new ArrayList<>(configurations.size());
 		for (int i= 0; i < items.length; i++) {
 			final EnvItem item= items[i];
 			final IREnvConfiguration rEnvConfig= configurations.get(i);
 			if (rEnvConfig.isDeleted()) {
 				continue;
 			}
 			synchronized (item.helpLock) {
 				switch (item.state) {
 				case HELP_LOADED:
 					withHelp.add(rEnvConfig.getReference());
 					continue;
 				case 0:
 					if (this.saveUtil.hasIndex(rEnvConfig)) {
 						withHelp.add(rEnvConfig.getReference());
 					}
 					else {
 						item.state= HELP_MISSING;
 					}
 					continue;
 				default:
 					continue;
 				}
 			}
 		}
 		return withHelp;
 	}

 	@Override
 	public boolean hasHelp(IREnv rEnv) {
 		if (rEnv != null) {
 			rEnv= rEnv.resolve();

 			if (rEnv != null) {
 				final String id= rEnv.getId();
 				EnvItem item;
 				synchronized (this.indexLock) {
 					item= this.helpIndexes.get(id);
 					if (item == null) {
 						item= new EnvItem(id);
 						this.helpIndexes.put(id, item);
 					}
 				}
 				synchronized (item.helpLock) {
 					switch (item.state) {
 					case HELP_LOADED:
 						return true;
 					case 0:
 						if (this.saveUtil.hasIndex(rEnv.getConfig())) {
 							return true;
 						}
 						else {
 							item.state= HELP_MISSING;
 							return false;
 						}
 					default:
 						return false;
 					}
 				}
 			}
 		}
 		return false;
 	}

 	@Override
 	public REnvHelp getHelp(IREnv rEnv) {
 		if (rEnv != null) {
 			rEnv= rEnv.resolve();

 			if (rEnv != null) {
 				final String rEnvId= rEnv.getId();
 				EnvItem item;
 				synchronized (this.indexLock) {
 					item= this.helpIndexes.get(rEnvId);
 					if (item == null) {
 						item= new EnvItem(rEnvId);
 						this.helpIndexes.put(rEnvId, item);
 					}
 				}
 				synchronized (item.helpLock) {
 					switch (item.state) {
 					case HELP_LOADED:
 						item.help.lock();
 						return item.help;
 					case 0:
 						final IREnvConfiguration rEnvConfig= rEnv.getConfig();
 						if (rEnvConfig != null) {
 							item.indexDir= rEnvConfig.getIndexDirectoryPath();
 							item.help= this.saveUtil.load(rEnvConfig);
 						}
 						if (item.help != null) {
 							item.state= HELP_LOADED;
 							item.help.lock();
 							return item.help;
 						}
 						else {
 							item.state= HELP_MISSING;
 							return null;
 						}
 					default:
 						return null;
 					}
 				}
 			}
 		}
 		return null;
 	}

 	public Object getIndexLock(final IREnv rEnv) {
 		final String id= rEnv.getId();
 		EnvItem item;
 		synchronized (this.indexLock) {
 			item= this.helpIndexes.get(id);
 			if (item == null) {
 				item= new EnvItem(id);
 				this.helpIndexes.put(id, item);
 			}
 		}
 		return item.indexLock;
 	}

 	@Override
 	public void dispose() {
 		this.prefAccess.removePreferenceSetListener(this);

 		stopServer();
 	}

 }
	/*=============================================================================#
	# Copyright (c) 2010, 2017 Stephan Wahlbrink and others.
	#
	# This program and the accompanying materials are made available under the
	# terms of the Eclipse Public License 2.0 which is available at
	# https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
	# which is available at https://www.apache.org/licenses/LICENSE-2.0.
	#
	# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
	#
	# Contributors:
	# Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
	#=============================================================================*/

	package org.eclipse.statet.internal.r.core.rhelp;

	import java.net.URI;
	import java.net.URISyntaxException;
	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;

	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.core.runtime.jobs.Job;

	import org.eclipse.statet.jcommons.collections.ImCollections;
	import org.eclipse.statet.jcommons.collections.ImIdentitySet;
	import org.eclipse.statet.jcommons.lang.Disposable;

	import org.eclipse.statet.ecommons.preferences.core.PreferenceAccess;
	import org.eclipse.statet.ecommons.preferences.core.PreferenceSetService;
	import org.eclipse.statet.ecommons.preferences.core.PreferenceSetService.ChangeEvent;
	import org.eclipse.statet.ecommons.preferences.core.util.PreferenceUtils;

	import org.eclipse.statet.internal.r.core.RCorePlugin;
	import org.eclipse.statet.internal.r.core.renv.REnvConfiguration;
	import org.eclipse.statet.internal.r.core.renv.REnvManager;
	import org.eclipse.statet.internal.r.core.rhelp.RHelpWebapp.ContentInfo;
	import org.eclipse.statet.r.core.RCore;
	import org.eclipse.statet.r.core.renv.IREnv;
	import org.eclipse.statet.r.core.renv.IREnvConfiguration;
	import org.eclipse.statet.r.core.renv.IREnvManager;
	import org.eclipse.statet.r.core.rhelp.IRHelpManager;
	import org.eclipse.statet.r.core.rhelp.IRHelpPage;
	import org.eclipse.statet.r.core.rhelp.IRHelpSearchRequestor;
	import org.eclipse.statet.r.core.rhelp.IRPkgHelp;
	import org.eclipse.statet.r.core.rhelp.RHelpSearchQuery;


	public class RHelpManager implements IRHelpManager, PreferenceSetService.ChangeListener, Disposable {
	// Compatible to dynamic R help
	// 1) With dynamic= TRUE from tools:::httpd()
	// Here generated links are of the forms
	// ../../pkg/help/topic
	// file.html
	// ../../pkg/html/file.html
	// and links are never missing: topics are always linked as
	// ../../pkg/help/topic for the current packages, and this means
	// 'search this package then all the others, and show all matches
	// if we need to go outside this packages'


	private static final ImIdentitySet<String> PREF_QUALIFIERS= ImCollections.newIdentitySet(
	IREnvManager.PREF_QUALIFIER );


	private static class EnvItem {

	final String id;

	int state;

	REnvHelp help;
	String indexDir;

	final Object helpLock= new Object();
	final Object indexLock= new Object();

	public EnvItem(final String id) {
	this.id= id;
	this.state= 0;
	this.help= null;
	this.indexDir= null;
	}

	}

	private class InitJob extends Job {

	public InitJob() {
	super("Prepare R help");
	setSystem(true);
	setPriority(Job.DECORATE);
	}

	@Override
	protected IStatus run(final IProgressMonitor monitor) {
	ensureIsRunning();

	final IREnv rEnv= RHelpManager.this.rEnvManager.getDefault().resolve();
	if (rEnv != null) {
	final REnvHelp help= getHelp(rEnv);
	if (help != null) {
	help.unlock();
	}
	}

	return Status.OK_STATUS;
	}

	}

	private static final int HELP_LOADED= 1;
	private static final int HELP_MISSING= -1;
	private static final int RENV_DELETED= -2;

	/**
	* Searches topic in library
	*/
	private static final String RHELP_TOPIC_PATH= "/topic"; //$NON-NLS-1$

	/**
	* Shows page (package, package/name or package/topic)
	*/
	private static final String RHELP_PAGE_PATH= "/page"; //$NON-NLS-1$


	private final PreferenceAccess prefAccess;

	private final REnvManager rEnvManager= RCorePlugin.getInstance().getREnvManager();
	private boolean running;

	private boolean httpdStarted;
	private JettyServer httpd;

	private final Object indexLock= new Object();

	private final SaveUtil saveUtil= new SaveUtil();

	private final Map<String, EnvItem> helpIndexes= new HashMap<>();


	public RHelpManager() {
	this.prefAccess= PreferenceUtils.getInstancePrefs();
	this.prefAccess.addPreferenceSetListener(this, PREF_QUALIFIERS);
	new InitJob().schedule(1000);
	}


	@Override
	public String getPageHttpUrl(final IRHelpPage page, final String target) {
	final IRPkgHelp pkgHelp= page.getPackage();
	return getPageHttpUrl(pkgHelp.getName(), page.getName(), pkgHelp.getREnv(), target);
	}

	@Override
	public String getPageHttpUrl(final String packageName, final String pageName,
	final IREnv rEnv, final String target) {
	checkRunning();
	final StringBuilder sb= new StringBuilder(64);
	sb.append(RHelpWebapp.CONTEXT_PATH);
	sb.append('/');
	sb.append(target);
	sb.append('/');
	sb.append(rEnv.getId());
	sb.append('/');
	sb.append(RHelpWebapp.CAT_LIBRARY);
	sb.append('/');
	sb.append(packageName);
	sb.append('/');
	if (pageName != null) {
	sb.append(RHelpWebapp.COMMAND_HTML_PAGE);
	sb.append('/');
	sb.append(pageName);
	sb.append(".html"); //$NON-NLS-1$
	}
	return createUrl(sb.toString());
	}

	@Override
	public String getTopicHttpUrl(final String topic, final String packageName,
	final IREnv rEnv, final String target) {
	checkRunning();
	final StringBuilder sb= new StringBuilder(64);
	sb.append(RHelpWebapp.CONTEXT_PATH);
	sb.append('/');
	sb.append(target);
	sb.append('/');
	sb.append(rEnv.getId());
	sb.append('/');
	sb.append(RHelpWebapp.CAT_LIBRARY);
	sb.append('/');
	sb.append(packageName);
	sb.append('/');
	sb.append(RHelpWebapp.COMMAND_HELP_TOPIC);
	sb.append('/');
	sb.append(topic);
	return createUrl(sb.toString());
	}

	@Override
	public String getREnvHttpUrl(final IREnv rEnv, final String target) {
	checkRunning();
	final StringBuilder sb= new StringBuilder(64);
	sb.append(RHelpWebapp.CONTEXT_PATH);
	sb.append('/');
	sb.append(target);
	sb.append('/');
	sb.append(rEnv.getId());
	sb.append('/');
	return createUrl(sb.toString());
	}

	@Override
	public String getPackageHttpUrl(final IRPkgHelp pkgHelp, final String target) {
	return getPageHttpUrl(pkgHelp.getName(), null, pkgHelp.getREnv(), target);
	}

	@Override
	public String toHttpUrl(final String url, final IREnv rEnv, final String target) {
	checkRunning();
	if (url.startsWith("rhelp:///")) { //$NON-NLS-1$
	final StringBuilder sb= new StringBuilder(64);
	sb.append(RHelpWebapp.CONTEXT_PATH);
	sb.append('/');
	sb.append(target);

	final String path= url.substring(8);
	final int idx1= (path.length() > 0) ? path.indexOf('/', 1) : -1;
	if (idx1 > 0) {
	final String command= path.substring(0, idx1);
	if (command.equals(RHELP_PAGE_PATH)) {
	sb.append('/');
	sb.append(rEnv.getId());
	sb.append('/');
	sb.append(RHelpWebapp.CAT_LIBRARY);
	final int idx2= path.indexOf('/', idx1 + 1);
	if (idx2 > idx1 + 1 && idx2 < path.length() - 1) {
	sb.append('/');
	sb.append(path.substring(idx1 + 1, idx2));
	sb.append('/');
	sb.append(RHelpWebapp.COMMAND_HTML_PAGE);
	sb.append('/');
	sb.append(path.substring(idx2 + 1));
	sb.append(".html"); //$NON-NLS-1$
	}
	else {
	sb.append('/');
	sb.append(path.substring(idx1 + 1, (idx2 > 0) ? idx2 : path.length()));
	sb.append('/');
	}
	return createUrl(sb.toString());
	}
	else if (command.equals(RHELP_TOPIC_PATH)) {
	sb.append('/');
	sb.append(rEnv.getId());
	sb.append('/');
	sb.append(RHelpWebapp.CAT_LIBRARY);
	sb.append('/');
	sb.append('-');
	sb.append('/');
	sb.append(RHelpWebapp.COMMAND_HELP_TOPIC);
	sb.append('/');
	sb.append(path.substring(idx1 + 1));
	return createUrl(sb.toString());
	}
	}
	else if (path.length() == 1) { // start
	sb.append('/');
	sb.append(rEnv.getId());
	sb.append('/');
	return createUrl(sb.toString());
	}
	return null;
	}
	if (url.startsWith("http://") && (rEnv != null \|\| target != null)) { //$NON-NLS-1$
	try {
	final URI uri= new URI(url);
	if (isDynamic(uri)) {
	final String path= uri.getPath();
	if (path != null && path.startsWith(RHelpWebapp.CONTEXT_PATH)) {
	final int idx2= path.indexOf('/', RHelpWebapp.CONTEXT_PATH.length() + 1);
	if (idx2 >= 0) {
	final StringBuilder sb= new StringBuilder(path.length() + 16);
	sb.append(RHelpWebapp.CONTEXT_PATH);
	sb.append('/');
	sb.append((target != null) ? target :
	path.substring(RHelpWebapp.CONTEXT_PATH.length() + 1, idx2));
	final String info= path.substring(idx2 + 1);
	if (rEnv != null) {
	final int idx3= info.indexOf('/');
	if (idx3 < 0) {
	return null;
	}
	sb.append('/');
	sb.append(rEnv.getId());
	sb.append(info.substring(idx3));
	}
	else {
	sb.append('/');
	sb.append(info);
	}
	return new URI(uri.getScheme(), uri.getUserInfo(), uri.getHost(), uri.getPort(),
	sb.toString(), uri.getQuery(), uri.getFragment()).toString();
	}
	}
	return null;
	}
	}
	catch (final Exception e) {}
	}
	return url;
	}

	@Override
	public String toHttpUrl(final Object object, final String target) {
	if (object == this) {
	return "about:blank"; //$NON-NLS-1$
	}
	if (object instanceof IREnv) {
	return getREnvHttpUrl((IREnv) object, target);
	}
	if (object instanceof IREnvConfiguration) {
	return getREnvHttpUrl(((IREnvConfiguration) object).getReference(), target);
	}
	if (object instanceof IRPkgHelp) {
	return getPackageHttpUrl((IRPkgHelp) object, target);
	}
	if (object instanceof IRHelpPage) {
	return getPageHttpUrl((IRHelpPage) object, target);
	}
	if (object instanceof String) {
	final String s= (String) object;
	if (s.startsWith("http://")) { //$NON-NLS-1$
	return s;
	}
	}
	return null;
	}

	private String createUrl(final String path) {
	try {
	return new URI("http", null, this.httpd.getHost(), this.httpd.getPort(), path, null, null) //$NON-NLS-1$
	.toASCIIString();
	}
	catch (final URISyntaxException e) {
	throw new IllegalStateException(e);
	}
	}

	@Override
	public Object getContentOfUrl(final String url) {
	try {
	final URI uri= new URI(url);
	final String path= uri.getPath();
	if (uri.getScheme() != null && uri.getScheme().equals("http") //$NON-NLS-1$
	&& path != null && path.startsWith(RHelpWebapp.CONTEXT_PATH)) {
	final int idx2= path.indexOf('/', RHelpWebapp.CONTEXT_PATH.length() + 1);
	if (idx2 >= 0) {
	final ContentInfo info= RHelpWebapp.extractContent(path.substring(idx2));
	if (info != null) {
	final IREnv rEnv= this.rEnvManager.get(info.rEnvId, null);
	if (rEnv != null && info.cat == RHelpWebapp.CAT_LIBRARY) {
	final REnvHelp help= getHelp(rEnv);
	if (help != null) {
	try {
	final IRPkgHelp pkgHelp= help.getPkgHelp(info.packageName);
	if (pkgHelp != null && info.command == RHelpWebapp.COMMAND_HTML_PAGE) {
	final IRHelpPage page= pkgHelp.getHelpPage(info.detail);
	if (page != null) {
	return page;
	}
	}
	return pkgHelp;
	}
	finally {
	help.unlock();
	}
	}
	return null;
	}
	if (rEnv != null && info.cat == RHelpWebapp.CAT_DOC) {
	return new Object[] { rEnv, null };
	}
	return rEnv;
	}
	}
	}
	} catch (final URISyntaxException e) {}
	return null;
	}

	@Override
	public boolean ensureIsRunning() {
	if (!this.httpdStarted) {
	startServer();
	}
	return this.running;
	}

	@Override
	public boolean isDynamic(final URI url) {
	checkRunning();
	return ((this.httpd.getHost().equals(url.getHost()) && this.httpd.getPort() == url.getPort()
	\|\| PORTABLE_URL_SCHEME.equals(url.getScheme()) ));
	}

	@Override
	public URI toHttpUrl(final URI url) throws URISyntaxException {
	if (isDynamic(url)) {
	String path= url.getPath();
	if (path != null && !path.startsWith("/rhelp")) {
	path= "/rhelp" + path;
	}
	return new URI("http", null, this.httpd.getHost(), this.httpd.getPort(),
	path, url.getQuery(), url.getFragment());
	}
	return url;
	}

	@Override
	public URI toPortableUrl(final URI url) throws URISyntaxException {
	if (isDynamic(url)) {
	String path= url.getPath();
	if (path != null && path.startsWith("/rhelp")) {
	path= path.substring(6);
	}
	return new URI(PORTABLE_URL_SCHEME, null, null, -1,
	path, url.getQuery(), url.getFragment());
	}
	return url;
	}

	private void checkRunning() {
	if (!ensureIsRunning()) {
	throw new UnsupportedOperationException("Help is not available.");
	}
	}

	private synchronized void startServer() {
	if (this.httpdStarted) {
	return;
	}
	final JettyServer httpd= new JettyServer();
	try {
	httpd.startServer();
	this.httpd= httpd;
	this.running= true;
	}
	catch (final Exception e) {
	RCorePlugin.log(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
	"An error occured when starting webserver for R help.", e));
	try {
	httpd.stopServer();
	}
	catch (final Exception ignore) {}
	}
	this.httpdStarted= true;
	}

	private synchronized void stopServer() {
	if (this.httpd == null) {
	return;
	}
	this.running= false;
	try {
	this.httpd.stopServer();
	this.httpd= null;
	}
	catch (final Exception e) {
	RCorePlugin.log(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
	"An error occured when stopping webserver for R help.", e));
	}
	}


	@Override
	public void search(final RHelpSearchQuery query, final IRHelpSearchRequestor requestor,
	final IProgressMonitor monitor) throws CoreException {
	if (query == null) {
	throw new NullPointerException("query"); //$NON-NLS-1$
	}
	if (requestor == null) {
	throw new NullPointerException("requestor"); //$NON-NLS-1$
	}
	final RHelpSearchQuery.Compiled compiledQuery= query.compile();
	final REnvHelp help= getHelp(compiledQuery.getREnv());
	if (help != null) {
	try {
	if (!help.search(compiledQuery, requestor)) {
	throw new CoreException(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
	"An internal error occurend when performing R help search.", null));
	}
	}
	finally {
	help.unlock();
	}
	}
	else {
	final IREnv rEnv= query.getREnv();
	if (rEnv == null \|\| rEnv.getConfig() == null) {
	throw new CoreException(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
	"The selected R environment doesn't exists.", null));
	}
	else {
	throw new CoreException(new Status(IStatus.ERROR, RCore.BUNDLE_ID, -1,
	"The R library of the selected R environment <code>" + compiledQuery.getREnv().getName() +
	"</code> is not yet indexed. Please run the indexer first to enable R help support.", null));
	}
	}
	}


	@Override
	public void preferenceChanged(final ChangeEvent event) {
	if (event.contains(IREnvManager.PREF_QUALIFIER)) {
	final List<IREnvConfiguration> configurations= this.rEnvManager.getConfigurations();
	final EnvItem[] items= new EnvItem[configurations.size()];
	synchronized (this.indexLock) {
	for (int i= 0; i < configurations.size(); i++) {
	items[i]= this.helpIndexes.get(configurations.get(i).getReference().getId());
	}
	}
	for (int i= 0; i < configurations.size(); i++) {
	if (items[i] != null) {
	final EnvItem item= items[i];
	final IREnvConfiguration config= configurations.get(i);
	REnvHelp oldHelp= null;
	synchronized (item.helpLock) {
	if (!((item.indexDir != null) ?
	item.indexDir.equals(config.getIndexDirectoryPath()) :
	null == config.getIndexDirectoryPath() )) {
	item.state= 0;
	oldHelp= item.help;
	item.help= null;
	}
	}
	if (oldHelp != null) {
	oldHelp.dispose();
	}
	}
	}
	}
	}

	public boolean updateHelp(final IREnvConfiguration rEnvConfig,
	final Map<String, String> rEnvSharedProperties, final REnvHelp help) {
	final IREnv rEnv= help.getREnv();
	final String rEnvId= rEnv.getId();
	EnvItem item;
	synchronized (this.indexLock) {
	item= this.helpIndexes.get(rEnvId);
	if (item == null) {
	item= new EnvItem(rEnvId);
	this.helpIndexes.put(rEnvId, item);
	}
	}
	REnvHelp oldHelp= null;
	try {
	synchronized (item.helpLock) {
	if (item.state == RENV_DELETED) {
	oldHelp= help;
	return false;
	}
	item.state= HELP_LOADED;
	item.indexDir= rEnvConfig.getIndexDirectoryPath();
	oldHelp= item.help;
	item.help= help;
	this.saveUtil.save(rEnvConfig, help);
	if (rEnvConfig instanceof REnvConfiguration) {
	((REnvConfiguration) rEnvConfig).updateSharedProperties(rEnvSharedProperties);
	}
	return true;
	}
	}
	finally {
	if (oldHelp != null) {
	oldHelp.dispose();
	}
	}
	}

	public void delete(final String id) {
	if (id != null && id.length() > 0) {
	EnvItem item;
	synchronized (this.indexLock) {
	item= this.helpIndexes.get(id);
	if (item == null) {
	item= new EnvItem(id);
	this.helpIndexes.put(id, item);
	}
	}
	REnvHelp oldHelp= null;
	synchronized (item.helpLock) {
	item.state= RENV_DELETED;
	oldHelp= item.help;
	item.help= null;
	}
	if (oldHelp != null) {
	oldHelp.dispose();
	}
	}
	}

	@Override
	public List<IREnv> getREnvWithHelp() {
	final List<IREnvConfiguration> configurations= this.rEnvManager.getConfigurations();
	final EnvItem[] items= new EnvItem[configurations.size()];
	synchronized (this.indexLock) {
	for (int i= 0; i < configurations.size(); i++) {
	final String id= configurations.get(i).getReference().getId();
	EnvItem item= this.helpIndexes.get(id);
	if (item == null) {
	item= new EnvItem(id);
	this.helpIndexes.put(id, item);
	}
	items[i]= item;
	}
	}
	final List<IREnv> withHelp= new ArrayList<>(configurations.size());
	for (int i= 0; i < items.length; i++) {
	final EnvItem item= items[i];
	final IREnvConfiguration rEnvConfig= configurations.get(i);
	if (rEnvConfig.isDeleted()) {
	continue;
	}
	synchronized (item.helpLock) {
	switch (item.state) {
	case HELP_LOADED:
	withHelp.add(rEnvConfig.getReference());
	continue;
	case 0:
	if (this.saveUtil.hasIndex(rEnvConfig)) {
	withHelp.add(rEnvConfig.getReference());
	}
	else {
	item.state= HELP_MISSING;
	}
	continue;
	default:
	continue;
	}
	}
	}
	return withHelp;
	}

	@Override
	public boolean hasHelp(IREnv rEnv) {
	if (rEnv != null) {
	rEnv= rEnv.resolve();

	if (rEnv != null) {
	final String id= rEnv.getId();
	EnvItem item;
	synchronized (this.indexLock) {
	item= this.helpIndexes.get(id);
	if (item == null) {
	item= new EnvItem(id);
	this.helpIndexes.put(id, item);
	}
	}
	synchronized (item.helpLock) {
	switch (item.state) {
	case HELP_LOADED:
	return true;
	case 0:
	if (this.saveUtil.hasIndex(rEnv.getConfig())) {
	return true;
	}
	else {
	item.state= HELP_MISSING;
	return false;
	}
	default:
	return false;
	}
	}
	}
	}
	return false;
	}

	@Override
	public REnvHelp getHelp(IREnv rEnv) {
	if (rEnv != null) {
	rEnv= rEnv.resolve();

	if (rEnv != null) {
	final String rEnvId= rEnv.getId();
	EnvItem item;
	synchronized (this.indexLock) {
	item= this.helpIndexes.get(rEnvId);
	if (item == null) {
	item= new EnvItem(rEnvId);
	this.helpIndexes.put(rEnvId, item);
	}
	}
	synchronized (item.helpLock) {
	switch (item.state) {
	case HELP_LOADED:
	item.help.lock();
	return item.help;
	case 0:
	final IREnvConfiguration rEnvConfig= rEnv.getConfig();
	if (rEnvConfig != null) {
	item.indexDir= rEnvConfig.getIndexDirectoryPath();
	item.help= this.saveUtil.load(rEnvConfig);
	}
	if (item.help != null) {
	item.state= HELP_LOADED;
	item.help.lock();
	return item.help;
	}
	else {
	item.state= HELP_MISSING;
	return null;
	}
	default:
	return null;
	}
	}
	}
	}
	return null;
	}

	public Object getIndexLock(final IREnv rEnv) {
	final String id= rEnv.getId();
	EnvItem item;
	synchronized (this.indexLock) {
	item= this.helpIndexes.get(id);
	if (item == null) {
	item= new EnvItem(id);
	this.helpIndexes.put(id, item);
	}
	}
	return item.indexLock;
	}

	@Override
	public void dispose() {
	this.prefAccess.removePreferenceSetListener(this);

	stopServer();
	}

	}