bundles/org.eclipse.e4.ui.css.swt.theme/src/org/eclipse/e4/ui/css/swt/internal/theme/ThemeEngine.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2010, 2018 Tom Schindl and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation
  *     Brian de Alwis - added support for multiple CSS engines
  *     Lars Vogel <Lars.Vogel@gmail.com> - Bug 422702
  *     IBM Corporation - initial API and implementation
  *     Lucas Bullen (Red Hat Inc.) - [Bug 527806] Ship all themes for all OS & WS
  *******************************************************************************/
 package org.eclipse.e4.ui.css.swt.internal.theme;

 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.FileLocator;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtension;
 import org.eclipse.core.runtime.IExtensionPoint;
 import org.eclipse.core.runtime.IExtensionRegistry;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.RegistryFactory;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
 import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.e4.ui.css.core.engine.CSSElementContext;
 import org.eclipse.e4.ui.css.core.engine.CSSEngine;
 import org.eclipse.e4.ui.css.core.util.impl.resources.FileResourcesLocatorImpl;
 import org.eclipse.e4.ui.css.core.util.impl.resources.OSGiResourceLocator;
 import org.eclipse.e4.ui.css.core.util.resources.IResourceLocator;
 import org.eclipse.e4.ui.css.swt.helpers.EclipsePreferencesHelper;
 import org.eclipse.e4.ui.css.swt.theme.ITheme;
 import org.eclipse.e4.ui.css.swt.theme.IThemeEngine;
 import org.eclipse.osgi.service.datalocation.Location;
 import org.eclipse.swt.widgets.Display;
 import org.osgi.framework.Bundle;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.FrameworkUtil;
 import org.osgi.framework.ServiceReference;
 import org.osgi.service.event.Event;
 import org.osgi.service.event.EventAdmin;
 import org.osgi.service.prefs.BackingStoreException;
 import org.w3c.css.sac.InputSource;
 import org.w3c.dom.Element;
 import org.w3c.dom.css.CSSStyleDeclaration;

 public class ThemeEngine implements IThemeEngine {
 	private List<Theme> themes = new ArrayList<>();
 	private List<CSSEngine> cssEngines = new ArrayList<>();

 	// kept for theme notifications only
 	private Display display;

 	private ITheme currentTheme;

 	private List<String> globalStyles = new ArrayList<>();
 	private List<IResourceLocator> globalSourceLocators = new ArrayList<>();

 	private HashMap<String, List<String>> stylesheets = new HashMap<>();
 	private HashMap<String, List<String>> modifiedStylesheets = new HashMap<>();
 	private HashMap<String, List<IResourceLocator>> sourceLocators = new HashMap<>();

 	private static final String THEMEID_KEY = "themeid";

 	public static final String THEME_PLUGIN_ID = "org.eclipse.e4.ui.css.swt.theme";

 	public static final String E4_DARK_THEME_ID = "org.eclipse.e4.ui.css.theme.e4_dark";

 	public ThemeEngine(Display display) {
 		this.display = display;

 		IExtensionRegistry registry = RegistryFactory.getRegistry();
 		IExtensionPoint extPoint = registry.getExtensionPoint(THEME_PLUGIN_ID);

 		//load any modified style sheets
 		Location configLocation = org.eclipse.core.runtime.Platform.getConfigurationLocation();
 		String e4CSSPath = null;
 		try {
 			URL locationURL = new URL(configLocation.getDataArea(ThemeEngine.THEME_PLUGIN_ID).toString());
 			File locationFile = new File(locationURL.getFile());
 			e4CSSPath = locationFile.getPath();
 		} catch (IOException e1) {
 		}

 		IPath path = new Path(e4CSSPath + File.separator);
 		File modDir= new File(path.toFile().toURI());
 		if (!modDir.exists()) {
 			modDir.mkdirs();
 		}

 		File[] modifiedFiles = modDir.listFiles();
 		String currentOS = Platform.getOS();
 		boolean e4_dark_mac_found = false;

 		for (IExtension e : extPoint.getExtensions()) {
 			for (IConfigurationElement ce : getPlatformMatches(e.getConfigurationElements())) {
 					if (ce.getName().equals("theme")) {
 						try {
 							String id = ce.getAttribute("id");
 							String os = ce.getAttribute("os");
 							String version = ce.getAttribute("os_version");

 							/*
 							 * Code to support e4 dark theme on Mac 10.13 and older. For e4 dark theme on
 							 * Mac, register the theme with matching OS version if specified.
 							 */
 							if (E4_DARK_THEME_ID.equals(id) && Platform.OS_MACOSX.equals(currentOS) && os != null
 									&& os.equals(currentOS)) {
 								// If e4 dark theme on Mac was already registered, don't try to match or
 								// register again.
 								if (e4_dark_mac_found) {
 									continue;
 								}
 								if (version != null && !isOsVersionMatch(version)) {
 									continue;
 								} else {
 									e4_dark_mac_found = true;
 									version = "";
 								}
 							}

 							if (version == null) {
 								version = "";
 							}

 							final String themeBaseId = id + version;
 							String themeId = themeBaseId;
 							String label = ce.getAttribute("label");
 							String originalCSSFile;
 							String basestylesheeturi = originalCSSFile = ce.getAttribute("basestylesheeturi");
 							if (!basestylesheeturi.startsWith("platform:/plugin/")) {
 								basestylesheeturi = "platform:/plugin/" + ce.getContributor().getName() + "/"
 										+ basestylesheeturi;
 							}
 							registerTheme(themeId, label, basestylesheeturi, version);

 							//check for modified files
 							if (modifiedFiles != null) {
 								int slash = originalCSSFile.lastIndexOf('/');
 								if (slash != -1) {
 									originalCSSFile = originalCSSFile.substring(slash + 1);
 									for (File modifiedFile : modifiedFiles) {
 										String modifiedFileName = modifiedFile.getName();
 										if (modifiedFileName.contains(".css") && modifiedFileName.equals(originalCSSFile)) {  //$NON-NLS-1$
 											//								modifiedStylesheets
 											ArrayList<String> styleSheets = new ArrayList<>();
 											styleSheets.add(modifiedFile.toURI().toString());
 											modifiedStylesheets.put(themeId, styleSheets);
 										}
 									}
 								}
 							}
 						} catch (IllegalArgumentException e1) {
 							ThemeEngineManager.logError(e1.getMessage(), e1);
 						}
 					}
 				}
 			}

 			for (IExtension e : extPoint.getExtensions()) {
 				for (IConfigurationElement ce : getPlatformMatches(e.getConfigurationElements())) {
 					if (ce.getName().equals("stylesheet")) {
 						IConfigurationElement[] cces = ce.getChildren("themeid");
 						if (cces.length == 0) {
 							registerStylesheet("platform:/plugin/"
 									+ ce.getContributor().getName() + "/"
 									+ ce.getAttribute("uri"));

 							for (IConfigurationElement resourceEl : ce
 									.getChildren("osgiresourcelocator")) {
 								String uri = resourceEl.getAttribute("uri");
 								if (uri != null) {
 									registerResourceLocator(new OSGiResourceLocator(
 											uri));
 								}
 							}
 						} else {
 							String[] themes = new String[cces.length];
 							for (int i = 0; i < cces.length; i++) {
 								themes[i] = cces[i].getAttribute("refid");
 							}
 							registerStylesheet(
 									"platform:/plugin/" + ce.getContributor().getName() + "/" + ce.getAttribute("uri"),
 									themes);

 							for (IConfigurationElement resourceEl : ce
 									.getChildren("osgiresourcelocator")) {
 								String uri = resourceEl.getAttribute("uri");
 								if (uri != null) {
 									registerResourceLocator(new OSGiResourceLocator(
 											uri));
 								}
 							}
 						}
 					}
 				}
 			}

 			// register a default resolver for platform uri's
 			registerResourceLocator(new OSGiResourceLocator(
 					"platform:/plugin/org.eclipse.ui.themes/css/"));
 			// register a default resolver for file uri's
 			registerResourceLocator(new FileResourcesLocatorImpl());
 			// FIXME: perhaps ResourcesLocatorManager shouldn't have a default?
 			// registerResourceLocator(new HttpResourcesLocatorImpl());
 		}


 		private boolean isOsVersionMatch(String osVersionList) {
 			boolean found = false;
 			String osVersion = System.getProperty("os.version");
 			if (osVersion != null) {
 				if (osVersionList != null) {
 					String[] osVersions = osVersionList.split(","); //$NON-NLS-1$
 					for (String osVersionFromTheme : osVersions) {
 						if (osVersionFromTheme != null) {
 							if (osVersion.contains(osVersionFromTheme)) {
 								found = true;
 								break;
 							}
 						}
 					}
 				}
 			}
 			return found;
 		}

 		@Override
 		public synchronized ITheme registerTheme(String id, String label, String basestylesheetURI)
 				throws IllegalArgumentException {
 			return  registerTheme(id, label, basestylesheetURI, "");
 		}

 		public synchronized ITheme registerTheme(String id, String label,
 				String basestylesheetURI, String osVersion) throws IllegalArgumentException {
 			for (Theme t : themes) {
 				if (t.getId().equals(id)) {
 					throw new IllegalArgumentException("A theme with the id '" + id
 							+ "' is already registered");
 				}
 			}
 			Theme theme = new Theme(id, label);
 			if (osVersion != "") {
 				theme.setOsVersion(osVersion);
 			}
 			themes.add(theme);
 			registerStyle(id, basestylesheetURI);
 			return theme;
 		}

 		@Override
 		public synchronized void registerStylesheet(String uri, String... themes) {
 			Bundle bundle = FrameworkUtil.getBundle(ThemeEngine.class);
 			String osname = bundle.getBundleContext().getProperty("osgi.os");
 			String wsname = bundle.getBundleContext().getProperty("osgi.ws");

 			uri = uri.replaceAll("\\$os\\$", osname).replaceAll("\\$ws\\$", wsname);

 			if (themes.length == 0) {
 				globalStyles.add(uri);
 			} else {
 				for (String t : themes) {
 					registerStyle(t, uri);
 				}
 			}
 		}

 		@Override
 		public synchronized void registerResourceLocator(IResourceLocator locator,
 				String... themes) {
 			if (themes.length == 0) {
 				globalSourceLocators.add(locator);
 			} else {
 				for (String t : themes) {
 					List<IResourceLocator> list = sourceLocators.get(t);
 					if (list == null) {
 						list = new ArrayList<>();
 						sourceLocators.put(t, list);
 					}
 					list.add(locator);
 				}
 			}
 		}

 		private void registerStyle(String id, String stylesheet) {
 			List<String> s = stylesheets.get(id);
 			if (s == null) {
 				s = new ArrayList<>();
 				stylesheets.put(id, s);
 			}
 			s.add(stylesheet);
 		}

 		private List<String> getAllStyles(String id) {
 			// check for any modifications first
 			List<String> m = modifiedStylesheets.get(id);
 			if (m != null) {
 				m = new ArrayList<>(m);
 				m.addAll(globalStyles);
 				return m;
 			}

 			List<String> s = stylesheets.get(id);
 			if (s == null) {
 				s = Collections.emptyList();
 			}

 			s = new ArrayList<>(s);
 			s.addAll(globalStyles);
 			return s;

 		}

 		private List<IResourceLocator> getResourceLocators(String id) {
 			List<IResourceLocator> list = new ArrayList<>(
 					globalSourceLocators);
 			List<IResourceLocator> s = sourceLocators.get(id);
 			if (s != null) {
 				list.addAll(s);
 			}

 			return list;
 		}

 		/**
 		 * Get all elements that have os/ws attributes that best match the current
 		 * platform.
 		 *
 		 * @param elements the elements to check
 		 * @return the best matches, if any
 		 */
 		private IConfigurationElement[] getPlatformMatches(IConfigurationElement[] elements) {
 			Bundle bundle = FrameworkUtil.getBundle(ThemeEngine.class);
 			String osname = bundle.getBundleContext().getProperty("osgi.os");
 			// TODO: Need to differentiate win32 versions
 			String wsname = bundle.getBundleContext().getProperty("osgi.ws");
 			ArrayList<IConfigurationElement> matchingElements = new ArrayList<>();
 			for (IConfigurationElement element : elements) {
 				String elementOs = element.getAttribute("os");
 				String elementWs = element.getAttribute("ws");
 				if (osname != null && (elementOs == null || elementOs.contains(osname))) {
 					matchingElements.add(element);
 				} else if (wsname != null && wsname.equalsIgnoreCase(elementWs)) {
 					matchingElements.add(element);
 				}
 			}
 			return matchingElements.toArray(new IConfigurationElement[matchingElements.size()]);
 		}

 		@Override
 		public void setTheme(String themeId, boolean restore) {
 			String osVersion = System.getProperty("os.version");
 			if (osVersion != null) {
 				boolean found = false;
 				for (Theme t : themes) {
 					String osVersionList = t.getOsVersion();
 					if (osVersionList != null) {
 						String[] osVersions = osVersionList.split(","); //$NON-NLS-1$
 						for (String osVersionFromTheme : osVersions) {
 							if (osVersionFromTheme != null && osVersion.contains(osVersionFromTheme)) {
 								String themeVersion = themeId + osVersionList;
 								if (t.getId().equals(themeVersion)) {
 									setTheme(t, restore);
 									found = true;
 									break;
 								}
 							}
 						}
 					}
 				}
 				if (found) {
 					return;
 				}
 			}
 			//try generic
 			for (Theme t : themes) {
 				if (t.getId().equals(themeId)) {
 					setTheme(t, restore);
 					break;
 				}
 			}
 		}

 		@Override
 		public void setTheme(ITheme theme, boolean restore) {
 			setTheme(theme, restore, false);
 		}

 		public void setTheme(ITheme theme, boolean restore, boolean force) {
 			Assert.isNotNull(theme, "The theme must not be null");

 			if (this.currentTheme != theme || force) {
 				if (currentTheme != null) {
 					for (IResourceLocator l : getResourceLocators(currentTheme
 							.getId())) {
 						for (CSSEngine engine : cssEngines) {
 							engine.getResourcesLocatorManager()
 							.unregisterResourceLocator(l);
 						}
 					}
 				}

 				this.currentTheme = theme;
 				for (CSSEngine engine : cssEngines) {
 					engine.reset();
 				}

 				for (IResourceLocator l : getResourceLocators(theme.getId())) {
 					for (CSSEngine engine : cssEngines) {
 						engine.getResourcesLocatorManager()
 						.registerResourceLocator(l);
 					}
 				}
 				for (String stylesheet : getAllStyles(theme.getId())) {
 					URL url;
 					InputStream stream = null;
 					try {
 						url = FileLocator.resolve(new URL(stylesheet));
 						for (CSSEngine engine : cssEngines) {
 							try {
 								stream = url.openStream();
 								InputSource source = new InputSource();
 								source.setByteStream(stream);
 								source.setURI(url.toString());
 								engine.parseStyleSheet(source);
 							} catch (IOException e) {
 								ThemeEngineManager.logError(e.getMessage(), e);
 							} finally {
 								if (stream != null) {
 									try {
 										stream.close();
 									} catch (IOException e) {
 										ThemeEngineManager.logError(e.getMessage(), e);
 									}
 								}
 							}
 						}
 					} catch (IOException e) {
 						ThemeEngineManager.logError(e.getMessage(), e);
 					}
 				}
 			}

 			if (restore) {
 				IEclipsePreferences pref = getPreferences();
 				EclipsePreferencesHelper.setPreviousThemeId(pref.get(THEMEID_KEY, null));
 				EclipsePreferencesHelper.setCurrentThemeId(theme.getId());

 				pref.put(THEMEID_KEY, theme.getId());
 				try {
 					pref.flush();
 				} catch (BackingStoreException e) {
 					ThemeEngineManager.logError(e.getMessage(), e);
 				}
 			}
 			sendThemeChangeEvent(restore);

 			for (CSSEngine engine : cssEngines) {
 				engine.reapply();
 			}
 		}

 		/**
 		 * Broadcast theme-change event using OSGi Event Admin.
 		 */
 		private void sendThemeChangeEvent(boolean restore) {
 			EventAdmin eventAdmin = getEventAdmin();
 			if (eventAdmin == null) {
 				return;
 			}
 			Map<String, Object> data = new HashMap<>();
 			data.put(IThemeEngine.Events.THEME_ENGINE, this);
 			data.put(IThemeEngine.Events.THEME, currentTheme);
 			data.put(IThemeEngine.Events.DEVICE, display);
 			data.put(IThemeEngine.Events.RESTORE, restore);
 			Event event = new Event(IThemeEngine.Events.THEME_CHANGED, data);
 			eventAdmin.sendEvent(event); // synchronous
 		}

 		public List<IResourceLocator> getCurrentResourceLocators() {
 			if(currentTheme == null) { return Collections.emptyList(); }
 			return getResourceLocators(currentTheme.getId());
 		}

 		private EventAdmin getEventAdmin() {
 			Bundle bundle = FrameworkUtil.getBundle(this.getClass());
 			if (bundle == null) {
 				return null;
 			}
 			BundleContext context = bundle.getBundleContext();
 			ServiceReference<EventAdmin> eventAdminRef = context.getServiceReference(EventAdmin.class);
 			return context.getService(eventAdminRef);
 		}

 		@Override
 		public synchronized List<ITheme> getThemes() {
 			return Collections.unmodifiableList(new ArrayList<ITheme>(themes));
 		}

 		@Override
 		public void applyStyles(Object widget, boolean applyStylesToChildNodes) {
 			for (CSSEngine engine : cssEngines) {
 				Element element = engine.getElement(widget);
 				if (element != null) {
 					engine.applyStyles(element, applyStylesToChildNodes);
 				}
 			}
 		}

 		private String getPreferenceThemeId() {
 			return getPreferences().get(THEMEID_KEY, null);
 		}

 		private IEclipsePreferences getPreferences() {
 			return InstanceScope.INSTANCE.getNode(FrameworkUtil.getBundle(ThemeEngine.class).getSymbolicName());
 		}

 		void copyFile(String from, String to) throws IOException {
 			FileInputStream fStream = null;
 			BufferedOutputStream outputStream = null;
 			try {
 				fStream = new FileInputStream(from);
 				outputStream = new BufferedOutputStream(new FileOutputStream(to));
 				byte[] buffer = new byte[4096];
 				int c;
 				while ((c = fStream.read(buffer)) != -1) {
 					outputStream.write(buffer, 0, c);
 				}

 			} finally {
 				if (fStream != null) {
 					fStream.close();
 				}
 				if (outputStream != null) {
 					outputStream.close();
 				}
 			}
 		}

 		@Override
 		public void restore(String alternateTheme) {
 			String prefThemeId = getPreferenceThemeId();
 			boolean flag = true;
 			if (prefThemeId != null) {
 				for (ITheme t : getThemes()) {
 					if (prefThemeId.equals(t.getId())) {
 						setTheme(t, false);
 						flag = false;
 						break;
 					}
 				}
 			}

 			// For Mac & GTK, if the system has Dark appearance set and Eclipse is using the
 			// default settings, then start Eclipse in Dark theme.

 			// Check that there is a dark theme present
 			boolean hasDarkTheme = getThemes().stream().anyMatch(t -> t.getId().startsWith(E4_DARK_THEME_ID));

 			String os = Platform.getOS();
 			String themeToRestore = (Platform.OS_LINUX.equals(os) || Platform.OS_MACOSX.equals(os))
 					&& Display.isSystemDarkTheme() && hasDarkTheme ? E4_DARK_THEME_ID : alternateTheme;
 			if (themeToRestore != null && flag) {
 				setTheme(themeToRestore, false);
 			}
 		}

 		@Override
 		public ITheme getActiveTheme() {
 			return currentTheme;
 		}

 		@Override
 		public CSSStyleDeclaration getStyle(Object widget) {
 			for (CSSEngine engine : cssEngines) {
 				CSSElementContext context = engine.getCSSElementContext(widget);
 				if (context != null) {
 					Element e = context.getElement();
 					if (e != null) {
 						return engine.getViewCSS().getComputedStyle(e, null);
 					}
 				}
 			}
 			return null;
 		}

 		public List<String> getStylesheets(ITheme selection) {
 			List<String> ss  = stylesheets.get(selection.getId());
 			return ss == null ? new ArrayList<>() : ss;
 		}

 		public void themeModified(ITheme theme, List<String> paths) {
 			modifiedStylesheets.put(theme.getId(), paths);
 			setTheme(theme, false, true);
 		}

 		public void resetCurrentTheme() {
 			if (currentTheme != null) {
 				setTheme(currentTheme, false, true);
 			}
 		}

 		public List<String> getModifiedStylesheets(ITheme selection) {
 			List<String> ss  = modifiedStylesheets.get(selection.getId());
 			return ss == null ? new ArrayList<>() : ss;
 		}

 		public void resetModifiedStylesheets(ITheme selection) {
 			modifiedStylesheets.remove(selection.getId());
 		}

 		@Override
 		public void addCSSEngine(CSSEngine cssEngine) {
 			cssEngines.add(cssEngine);
 			resetCurrentTheme();
 		}

 		public Collection<CSSEngine> getCSSEngines() {
 			return cssEngines;
 		}

 		@Override
 		public void removeCSSEngine(CSSEngine cssEngine) {
 			cssEngines.remove(cssEngine);
 		}
 	}
	/*******************************************************************************
	* Copyright (c) 2010, 2018 Tom Schindl and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation
	* Brian de Alwis - added support for multiple CSS engines
	* Lars Vogel <Lars.Vogel@gmail.com> - Bug 422702
	* IBM Corporation - initial API and implementation
	* Lucas Bullen (Red Hat Inc.) - [Bug 527806] Ship all themes for all OS & WS
	*******************************************************************************/
	package org.eclipse.e4.ui.css.swt.internal.theme;

	import java.io.BufferedOutputStream;
	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.net.URL;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;

	import org.eclipse.core.runtime.Assert;
	import org.eclipse.core.runtime.FileLocator;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IExtension;
	import org.eclipse.core.runtime.IExtensionPoint;
	import org.eclipse.core.runtime.IExtensionRegistry;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.Path;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.core.runtime.RegistryFactory;
	import org.eclipse.core.runtime.preferences.IEclipsePreferences;
	import org.eclipse.core.runtime.preferences.InstanceScope;
	import org.eclipse.e4.ui.css.core.engine.CSSElementContext;
	import org.eclipse.e4.ui.css.core.engine.CSSEngine;
	import org.eclipse.e4.ui.css.core.util.impl.resources.FileResourcesLocatorImpl;
	import org.eclipse.e4.ui.css.core.util.impl.resources.OSGiResourceLocator;
	import org.eclipse.e4.ui.css.core.util.resources.IResourceLocator;
	import org.eclipse.e4.ui.css.swt.helpers.EclipsePreferencesHelper;
	import org.eclipse.e4.ui.css.swt.theme.ITheme;
	import org.eclipse.e4.ui.css.swt.theme.IThemeEngine;
	import org.eclipse.osgi.service.datalocation.Location;
	import org.eclipse.swt.widgets.Display;
	import org.osgi.framework.Bundle;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.FrameworkUtil;
	import org.osgi.framework.ServiceReference;
	import org.osgi.service.event.Event;
	import org.osgi.service.event.EventAdmin;
	import org.osgi.service.prefs.BackingStoreException;
	import org.w3c.css.sac.InputSource;
	import org.w3c.dom.Element;
	import org.w3c.dom.css.CSSStyleDeclaration;

	public class ThemeEngine implements IThemeEngine {
	private List<Theme> themes = new ArrayList<>();
	private List<CSSEngine> cssEngines = new ArrayList<>();

	// kept for theme notifications only
	private Display display;

	private ITheme currentTheme;

	private List<String> globalStyles = new ArrayList<>();
	private List<IResourceLocator> globalSourceLocators = new ArrayList<>();

	private HashMap<String, List<String>> stylesheets = new HashMap<>();
	private HashMap<String, List<String>> modifiedStylesheets = new HashMap<>();
	private HashMap<String, List<IResourceLocator>> sourceLocators = new HashMap<>();

	private static final String THEMEID_KEY = "themeid";

	public static final String THEME_PLUGIN_ID = "org.eclipse.e4.ui.css.swt.theme";

	public static final String E4_DARK_THEME_ID = "org.eclipse.e4.ui.css.theme.e4_dark";

	public ThemeEngine(Display display) {
	this.display = display;

	IExtensionRegistry registry = RegistryFactory.getRegistry();
	IExtensionPoint extPoint = registry.getExtensionPoint(THEME_PLUGIN_ID);

	//load any modified style sheets
	Location configLocation = org.eclipse.core.runtime.Platform.getConfigurationLocation();
	String e4CSSPath = null;
	try {
	URL locationURL = new URL(configLocation.getDataArea(ThemeEngine.THEME_PLUGIN_ID).toString());
	File locationFile = new File(locationURL.getFile());
	e4CSSPath = locationFile.getPath();
	} catch (IOException e1) {
	}

	IPath path = new Path(e4CSSPath + File.separator);
	File modDir= new File(path.toFile().toURI());
	if (!modDir.exists()) {
	modDir.mkdirs();
	}

	File[] modifiedFiles = modDir.listFiles();
	String currentOS = Platform.getOS();
	boolean e4_dark_mac_found = false;

	for (IExtension e : extPoint.getExtensions()) {
	for (IConfigurationElement ce : getPlatformMatches(e.getConfigurationElements())) {
	if (ce.getName().equals("theme")) {
	try {
	String id = ce.getAttribute("id");
	String os = ce.getAttribute("os");
	String version = ce.getAttribute("os_version");

	/*
	* Code to support e4 dark theme on Mac 10.13 and older. For e4 dark theme on
	* Mac, register the theme with matching OS version if specified.
	*/
	if (E4_DARK_THEME_ID.equals(id) && Platform.OS_MACOSX.equals(currentOS) && os != null
	&& os.equals(currentOS)) {
	// If e4 dark theme on Mac was already registered, don't try to match or
	// register again.
	if (e4_dark_mac_found) {
	continue;
	}
	if (version != null && !isOsVersionMatch(version)) {
	continue;
	} else {
	e4_dark_mac_found = true;
	version = "";
	}
	}

	if (version == null) {
	version = "";
	}

	final String themeBaseId = id + version;
	String themeId = themeBaseId;
	String label = ce.getAttribute("label");
	String originalCSSFile;
	String basestylesheeturi = originalCSSFile = ce.getAttribute("basestylesheeturi");
	if (!basestylesheeturi.startsWith("platform:/plugin/")) {
	basestylesheeturi = "platform:/plugin/" + ce.getContributor().getName() + "/"
	+ basestylesheeturi;
	}
	registerTheme(themeId, label, basestylesheeturi, version);

	//check for modified files
	if (modifiedFiles != null) {
	int slash = originalCSSFile.lastIndexOf('/');
	if (slash != -1) {
	originalCSSFile = originalCSSFile.substring(slash + 1);
	for (File modifiedFile : modifiedFiles) {
	String modifiedFileName = modifiedFile.getName();
	if (modifiedFileName.contains(".css") && modifiedFileName.equals(originalCSSFile)) { //$NON-NLS-1$
	// modifiedStylesheets
	ArrayList<String> styleSheets = new ArrayList<>();
	styleSheets.add(modifiedFile.toURI().toString());
	modifiedStylesheets.put(themeId, styleSheets);
	}
	}
	}
	}
	} catch (IllegalArgumentException e1) {
	ThemeEngineManager.logError(e1.getMessage(), e1);
	}
	}
	}
	}

	for (IExtension e : extPoint.getExtensions()) {
	for (IConfigurationElement ce : getPlatformMatches(e.getConfigurationElements())) {
	if (ce.getName().equals("stylesheet")) {
	IConfigurationElement[] cces = ce.getChildren("themeid");
	if (cces.length == 0) {
	registerStylesheet("platform:/plugin/"
	+ ce.getContributor().getName() + "/"
	+ ce.getAttribute("uri"));

	for (IConfigurationElement resourceEl : ce
	.getChildren("osgiresourcelocator")) {
	String uri = resourceEl.getAttribute("uri");
	if (uri != null) {
	registerResourceLocator(new OSGiResourceLocator(
	uri));
	}
	}
	} else {
	String[] themes = new String[cces.length];
	for (int i = 0; i < cces.length; i++) {
	themes[i] = cces[i].getAttribute("refid");
	}
	registerStylesheet(
	"platform:/plugin/" + ce.getContributor().getName() + "/" + ce.getAttribute("uri"),
	themes);

	for (IConfigurationElement resourceEl : ce
	.getChildren("osgiresourcelocator")) {
	String uri = resourceEl.getAttribute("uri");
	if (uri != null) {
	registerResourceLocator(new OSGiResourceLocator(
	uri));
	}
	}
	}
	}
	}
	}

	// register a default resolver for platform uri's
	registerResourceLocator(new OSGiResourceLocator(
	"platform:/plugin/org.eclipse.ui.themes/css/"));
	// register a default resolver for file uri's
	registerResourceLocator(new FileResourcesLocatorImpl());
	// FIXME: perhaps ResourcesLocatorManager shouldn't have a default?
	// registerResourceLocator(new HttpResourcesLocatorImpl());
	}


	private boolean isOsVersionMatch(String osVersionList) {
	boolean found = false;
	String osVersion = System.getProperty("os.version");
	if (osVersion != null) {
	if (osVersionList != null) {
	String[] osVersions = osVersionList.split(","); //$NON-NLS-1$
	for (String osVersionFromTheme : osVersions) {
	if (osVersionFromTheme != null) {
	if (osVersion.contains(osVersionFromTheme)) {
	found = true;
	break;
	}
	}
	}
	}
	}
	return found;
	}

	@Override
	public synchronized ITheme registerTheme(String id, String label, String basestylesheetURI)
	throws IllegalArgumentException {
	return registerTheme(id, label, basestylesheetURI, "");
	}

	public synchronized ITheme registerTheme(String id, String label,
	String basestylesheetURI, String osVersion) throws IllegalArgumentException {
	for (Theme t : themes) {
	if (t.getId().equals(id)) {
	throw new IllegalArgumentException("A theme with the id '" + id
	+ "' is already registered");
	}
	}
	Theme theme = new Theme(id, label);
	if (osVersion != "") {
	theme.setOsVersion(osVersion);
	}
	themes.add(theme);
	registerStyle(id, basestylesheetURI);
	return theme;
	}

	@Override
	public synchronized void registerStylesheet(String uri, String... themes) {
	Bundle bundle = FrameworkUtil.getBundle(ThemeEngine.class);
	String osname = bundle.getBundleContext().getProperty("osgi.os");
	String wsname = bundle.getBundleContext().getProperty("osgi.ws");

	uri = uri.replaceAll("\\$os\\$", osname).replaceAll("\\$ws\\$", wsname);

	if (themes.length == 0) {
	globalStyles.add(uri);
	} else {
	for (String t : themes) {
	registerStyle(t, uri);
	}
	}
	}

	@Override
	public synchronized void registerResourceLocator(IResourceLocator locator,
	String... themes) {
	if (themes.length == 0) {
	globalSourceLocators.add(locator);
	} else {
	for (String t : themes) {
	List<IResourceLocator> list = sourceLocators.get(t);
	if (list == null) {
	list = new ArrayList<>();
	sourceLocators.put(t, list);
	}
	list.add(locator);
	}
	}
	}

	private void registerStyle(String id, String stylesheet) {
	List<String> s = stylesheets.get(id);
	if (s == null) {
	s = new ArrayList<>();
	stylesheets.put(id, s);
	}
	s.add(stylesheet);
	}

	private List<String> getAllStyles(String id) {
	// check for any modifications first
	List<String> m = modifiedStylesheets.get(id);
	if (m != null) {
	m = new ArrayList<>(m);
	m.addAll(globalStyles);
	return m;
	}

	List<String> s = stylesheets.get(id);
	if (s == null) {
	s = Collections.emptyList();
	}

	s = new ArrayList<>(s);
	s.addAll(globalStyles);
	return s;

	}

	private List<IResourceLocator> getResourceLocators(String id) {
	List<IResourceLocator> list = new ArrayList<>(
	globalSourceLocators);
	List<IResourceLocator> s = sourceLocators.get(id);
	if (s != null) {
	list.addAll(s);
	}

	return list;
	}

	/**
	* Get all elements that have os/ws attributes that best match the current
	* platform.
	*
	* @param elements the elements to check
	* @return the best matches, if any
	*/
	private IConfigurationElement[] getPlatformMatches(IConfigurationElement[] elements) {
	Bundle bundle = FrameworkUtil.getBundle(ThemeEngine.class);
	String osname = bundle.getBundleContext().getProperty("osgi.os");
	// TODO: Need to differentiate win32 versions
	String wsname = bundle.getBundleContext().getProperty("osgi.ws");
	ArrayList<IConfigurationElement> matchingElements = new ArrayList<>();
	for (IConfigurationElement element : elements) {
	String elementOs = element.getAttribute("os");
	String elementWs = element.getAttribute("ws");
	if (osname != null && (elementOs == null \|\| elementOs.contains(osname))) {
	matchingElements.add(element);
	} else if (wsname != null && wsname.equalsIgnoreCase(elementWs)) {
	matchingElements.add(element);
	}
	}
	return matchingElements.toArray(new IConfigurationElement[matchingElements.size()]);
	}

	@Override
	public void setTheme(String themeId, boolean restore) {
	String osVersion = System.getProperty("os.version");
	if (osVersion != null) {
	boolean found = false;
	for (Theme t : themes) {
	String osVersionList = t.getOsVersion();
	if (osVersionList != null) {
	String[] osVersions = osVersionList.split(","); //$NON-NLS-1$
	for (String osVersionFromTheme : osVersions) {
	if (osVersionFromTheme != null && osVersion.contains(osVersionFromTheme)) {
	String themeVersion = themeId + osVersionList;
	if (t.getId().equals(themeVersion)) {
	setTheme(t, restore);
	found = true;
	break;
	}
	}
	}
	}
	}
	if (found) {
	return;
	}
	}
	//try generic
	for (Theme t : themes) {
	if (t.getId().equals(themeId)) {
	setTheme(t, restore);
	break;
	}
	}
	}

	@Override
	public void setTheme(ITheme theme, boolean restore) {
	setTheme(theme, restore, false);
	}

	public void setTheme(ITheme theme, boolean restore, boolean force) {
	Assert.isNotNull(theme, "The theme must not be null");

	if (this.currentTheme != theme \|\| force) {
	if (currentTheme != null) {
	for (IResourceLocator l : getResourceLocators(currentTheme
	.getId())) {
	for (CSSEngine engine : cssEngines) {
	engine.getResourcesLocatorManager()
	.unregisterResourceLocator(l);
	}
	}
	}

	this.currentTheme = theme;
	for (CSSEngine engine : cssEngines) {
	engine.reset();
	}

	for (IResourceLocator l : getResourceLocators(theme.getId())) {
	for (CSSEngine engine : cssEngines) {
	engine.getResourcesLocatorManager()
	.registerResourceLocator(l);
	}
	}
	for (String stylesheet : getAllStyles(theme.getId())) {
	URL url;
	InputStream stream = null;
	try {
	url = FileLocator.resolve(new URL(stylesheet));
	for (CSSEngine engine : cssEngines) {
	try {
	stream = url.openStream();
	InputSource source = new InputSource();
	source.setByteStream(stream);
	source.setURI(url.toString());
	engine.parseStyleSheet(source);
	} catch (IOException e) {
	ThemeEngineManager.logError(e.getMessage(), e);
	} finally {
	if (stream != null) {
	try {
	stream.close();
	} catch (IOException e) {
	ThemeEngineManager.logError(e.getMessage(), e);
	}
	}
	}
	}
	} catch (IOException e) {
	ThemeEngineManager.logError(e.getMessage(), e);
	}
	}
	}

	if (restore) {
	IEclipsePreferences pref = getPreferences();
	EclipsePreferencesHelper.setPreviousThemeId(pref.get(THEMEID_KEY, null));
	EclipsePreferencesHelper.setCurrentThemeId(theme.getId());

	pref.put(THEMEID_KEY, theme.getId());
	try {
	pref.flush();
	} catch (BackingStoreException e) {
	ThemeEngineManager.logError(e.getMessage(), e);
	}
	}
	sendThemeChangeEvent(restore);

	for (CSSEngine engine : cssEngines) {
	engine.reapply();
	}
	}

	/**
	* Broadcast theme-change event using OSGi Event Admin.
	*/
	private void sendThemeChangeEvent(boolean restore) {
	EventAdmin eventAdmin = getEventAdmin();
	if (eventAdmin == null) {
	return;
	}
	Map<String, Object> data = new HashMap<>();
	data.put(IThemeEngine.Events.THEME_ENGINE, this);
	data.put(IThemeEngine.Events.THEME, currentTheme);
	data.put(IThemeEngine.Events.DEVICE, display);
	data.put(IThemeEngine.Events.RESTORE, restore);
	Event event = new Event(IThemeEngine.Events.THEME_CHANGED, data);
	eventAdmin.sendEvent(event); // synchronous
	}

	public List<IResourceLocator> getCurrentResourceLocators() {
	if(currentTheme == null) { return Collections.emptyList(); }
	return getResourceLocators(currentTheme.getId());
	}

	private EventAdmin getEventAdmin() {
	Bundle bundle = FrameworkUtil.getBundle(this.getClass());
	if (bundle == null) {
	return null;
	}
	BundleContext context = bundle.getBundleContext();
	ServiceReference<EventAdmin> eventAdminRef = context.getServiceReference(EventAdmin.class);
	return context.getService(eventAdminRef);
	}

	@Override
	public synchronized List<ITheme> getThemes() {
	return Collections.unmodifiableList(new ArrayList<ITheme>(themes));
	}

	@Override
	public void applyStyles(Object widget, boolean applyStylesToChildNodes) {
	for (CSSEngine engine : cssEngines) {
	Element element = engine.getElement(widget);
	if (element != null) {
	engine.applyStyles(element, applyStylesToChildNodes);
	}
	}
	}

	private String getPreferenceThemeId() {
	return getPreferences().get(THEMEID_KEY, null);
	}

	private IEclipsePreferences getPreferences() {
	return InstanceScope.INSTANCE.getNode(FrameworkUtil.getBundle(ThemeEngine.class).getSymbolicName());
	}

	void copyFile(String from, String to) throws IOException {
	FileInputStream fStream = null;
	BufferedOutputStream outputStream = null;
	try {
	fStream = new FileInputStream(from);
	outputStream = new BufferedOutputStream(new FileOutputStream(to));
	byte[] buffer = new byte[4096];
	int c;
	while ((c = fStream.read(buffer)) != -1) {
	outputStream.write(buffer, 0, c);
	}

	} finally {
	if (fStream != null) {
	fStream.close();
	}
	if (outputStream != null) {
	outputStream.close();
	}
	}
	}

	@Override
	public void restore(String alternateTheme) {
	String prefThemeId = getPreferenceThemeId();
	boolean flag = true;
	if (prefThemeId != null) {
	for (ITheme t : getThemes()) {
	if (prefThemeId.equals(t.getId())) {
	setTheme(t, false);
	flag = false;
	break;
	}
	}
	}

	// For Mac & GTK, if the system has Dark appearance set and Eclipse is using the
	// default settings, then start Eclipse in Dark theme.

	// Check that there is a dark theme present
	boolean hasDarkTheme = getThemes().stream().anyMatch(t -> t.getId().startsWith(E4_DARK_THEME_ID));

	String os = Platform.getOS();
	String themeToRestore = (Platform.OS_LINUX.equals(os) \|\| Platform.OS_MACOSX.equals(os))
	&& Display.isSystemDarkTheme() && hasDarkTheme ? E4_DARK_THEME_ID : alternateTheme;
	if (themeToRestore != null && flag) {
	setTheme(themeToRestore, false);
	}
	}

	@Override
	public ITheme getActiveTheme() {
	return currentTheme;
	}

	@Override
	public CSSStyleDeclaration getStyle(Object widget) {
	for (CSSEngine engine : cssEngines) {
	CSSElementContext context = engine.getCSSElementContext(widget);
	if (context != null) {
	Element e = context.getElement();
	if (e != null) {
	return engine.getViewCSS().getComputedStyle(e, null);
	}
	}
	}
	return null;
	}

	public List<String> getStylesheets(ITheme selection) {
	List<String> ss = stylesheets.get(selection.getId());
	return ss == null ? new ArrayList<>() : ss;
	}

	public void themeModified(ITheme theme, List<String> paths) {
	modifiedStylesheets.put(theme.getId(), paths);
	setTheme(theme, false, true);
	}

	public void resetCurrentTheme() {
	if (currentTheme != null) {
	setTheme(currentTheme, false, true);
	}
	}

	public List<String> getModifiedStylesheets(ITheme selection) {
	List<String> ss = modifiedStylesheets.get(selection.getId());
	return ss == null ? new ArrayList<>() : ss;
	}

	public void resetModifiedStylesheets(ITheme selection) {
	modifiedStylesheets.remove(selection.getId());
	}

	@Override
	public void addCSSEngine(CSSEngine cssEngine) {
	cssEngines.add(cssEngine);
	resetCurrentTheme();
	}

	public Collection<CSSEngine> getCSSEngines() {
	return cssEngines;
	}

	@Override
	public void removeCSSEngine(CSSEngine cssEngine) {
	cssEngines.remove(cssEngine);
	}
	}