Created encoding provider for project properties, which is required for running workflows that load resources with different encodings

Change-Id: I7fb9963e4fbd418855a574d11b811a4c0b177e58
Signed-off-by: Miro Spönemann <miro.spoenemann@itemis.de>

plugins/org.eclipse.xtext/src/org/eclipse/xtext/mwe/AbstractReader.java

@@ -49,6 +49,9 @@ public abstract class AbstractReader extends AbstractWorkflowComponent2 {
 
 	private List<Injector> injectors = Lists.newArrayList();
 
+	/**
+	 * Register a language setup. Only the first registered setup is used to inject the resource set.
+	 */
 	public void addRegister(ISetup setup) {
 		injectors.add(setup.createInjectorAndDoEMFRegistration());
 	}

plugins/org.eclipse.xtext/src/org/eclipse/xtext/parser/EclipseProjectPropertiesEncodingProvider.java

@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright (c) 2014 itemis AG (http://www.itemis.eu) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.xtext.parser;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.Properties;
+
+import org.eclipse.emf.common.util.URI;
+
+/**
+ * Use this class to retrieve resource encodings from Eclipse project properties. The provider can be used
+ * without a running Eclipse context, but depends on resources being stored in Eclipse projects.
+ * Parts of the implementation are copied from {@link org.eclipse.core.internal.preferences.EclipsePreferences}.
+ * 
+ * @author Miro Spoenemann - Initial contribution and API
+ * @since 2.8
+ */
+public class EclipseProjectPropertiesEncodingProvider extends IEncodingProvider.Runtime {
+	
+	private static final String PROPERTIES_DIRNAME = ".settings";
+	private static final String PREFS_FILE_EXTENSION = "prefs";
+	private static final String PROJECT_PROPERTIES = "<project>";
+	private static final String ENCODING_PREFIX = "encoding/";
+	
+	@Override
+	public String getEncoding(URI uri) {
+		// If a default encoding is explicitly set, use that one
+		String result = getDefaultEncoding();
+		if (result != null)
+			return result;
+		
+		// Read the project properties
+		try {
+			result = getFromProperties(uri);
+			if (result != null)
+				return result;
+		} catch (IOException e) {
+		}
+		
+		// Fall back to the standard encoding
+		return super.getEncoding(uri);
+	}
+	
+	protected String getFromProperties(URI uri) throws IOException {
+		if (!uri.isHierarchical())
+			return null;
+		
+		URI projectURI = uri;
+		boolean projectFound = false;
+		do {
+			projectURI = projectURI.trimSegments(1);
+			if (new File(projectURI.path(), ".project").exists()) {
+				projectFound = true;
+			}
+			if (!projectFound && projectURI.segmentCount() == 0)
+				// The resource is not contained in a project
+				return null;
+		} while (!projectFound);
+		
+		Properties properties = loadProperties(projectURI);
+		URI resourceUri = URI.createHierarchicalURI(Arrays.copyOfRange(uri.segments(),
+				projectURI.segmentCount(), uri.segmentCount()), null, null);
+		return getValue(properties, resourceUri, ENCODING_PREFIX);
+	}
+
+	protected Properties loadProperties(URI projectURI) throws IOException {
+		URI propertiesUri = projectURI.appendSegment(PROPERTIES_DIRNAME).appendSegment("org.eclipse.core.resources")
+				.appendFileExtension(PREFS_FILE_EXTENSION);
+		InputStream input = null;
+		Properties result = new Properties();
+		try {
+			input = new FileInputStream(propertiesUri.path());
+			result.load(input);
+		} catch (FileNotFoundException e) {
+			// File doesn't exist but that's ok
+		} finally {
+			if (input != null) {
+				try {
+					input.close();
+				} catch (IOException e) {
+				}
+			}
+		}
+		return result;
+	}
+	
+	protected String getValue(Properties properties, URI resourceUri, String prefix) {
+		URI path = resourceUri;
+		do {
+			String value = properties.getProperty(prefix + path.path());
+			if (value != null)
+				return value;
+			path = path.trimSegments(1);
+		} while (path.segmentCount() > 0);
+		String value = properties.getProperty(prefix + PROJECT_PROPERTIES);
+		if (value != null)
+			return value;
+		return null;
+	}
+	
+}

plugins/org.eclipse.xtext/src/org/eclipse/xtext/service/DefaultRuntimeModule.java

@@ -25,6 +25,7 @@ import org.eclipse.xtext.linking.lazy.LazyURIEncoder;
 import org.eclipse.xtext.naming.IQualifiedNameProvider;
 import org.eclipse.xtext.naming.SimpleNameProvider;
 import org.eclipse.xtext.parser.IEncodingProvider;
+import org.eclipse.xtext.parser.EclipseProjectPropertiesEncodingProvider;
 import org.eclipse.xtext.parser.antlr.AntlrTokenToStringConverter;
 import org.eclipse.xtext.parser.antlr.ITokenDefProvider;
 import org.eclipse.xtext.parser.antlr.NullTokenDefProvider;
@@ -204,7 +205,7 @@ public abstract class DefaultRuntimeModule extends AbstractGenericModule {
 	}
 	
 	public void configureRuntimeEncodingProvider(Binder binder) {
-		binder.bind(IEncodingProvider.class).annotatedWith(DispatchingProvider.Runtime.class).to(IEncodingProvider.Runtime.class);
+		binder.bind(IEncodingProvider.class).annotatedWith(DispatchingProvider.Runtime.class).to(EclipseProjectPropertiesEncodingProvider.class);
 	}
 
 	public Class<? extends Provider<IEncodingProvider>> provideIEncodingProvider() {