ltk/org.eclipse.statet.ltk.ui/src/org/eclipse/statet/ltk/ui/sourceediting/assist/PathCompletionComputor.java - statet/org.eclipse.statet-ltk - Git at Google

 /*=============================================================================#
  # Copyright (c) 2007, 2020 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.ltk.ui.sourceediting.assist;

 import java.io.File;
 import java.util.Arrays;

 import com.ibm.icu.text.Collator;

 import org.eclipse.core.filesystem.EFS;
 import org.eclipse.core.filesystem.IFileStore;
 import org.eclipse.core.filesystem.URIUtil;
 import org.eclipse.core.resources.IContainer;
 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.Position;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.ui.ISharedImages;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.statushandlers.StatusManager;

 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 import org.eclipse.statet.jcommons.lang.Nullable;
 import org.eclipse.statet.jcommons.lang.SystemUtils;
 import org.eclipse.statet.jcommons.text.core.SearchPattern;
 import org.eclipse.statet.jcommons.text.core.TextRegion;

 import org.eclipse.statet.ecommons.runtime.core.util.PathUtils;
 import org.eclipse.statet.ecommons.ui.SharedUIResources;

 import org.eclipse.statet.internal.ltk.ui.LTKUIPlugin;
 import org.eclipse.statet.ltk.ui.sourceediting.ISourceEditor;
 import org.eclipse.statet.ltk.ui.sourceediting.assist.SourceProposal.ProposalParameters;


 /**
  * Content assist processor for completion of path for local file system resources.
  */
 @NonNullByDefault
 public abstract class PathCompletionComputor implements ContentAssistComputer {


 	protected class ResourceCompletionProposal extends SourceProposal<AssistInvocationContext> {

 		private final IFileStore fileStore;
 		private final boolean isDirectory;
 		/** The parent in the workspace, if in workspace */
 		private final IContainer workspaceRef;

 		private final String name;

 		/** Final completion string */
 		private @Nullable String completion;


 		/**
 		 * Creates a new completion proposal for a resource
 		 *
 		 * @param offset the offset in the document where to insert the completion
 		 * @param fileStore the EFS resource handle
 		 * @param explicitName optional explicit name used instead of the name of the fileStore
 		 * @param prefix optional prefix to prefix before the name
 		 * @param workspaceRef the workspace resource handle, if the resource is in the workspace
 		 */
 		public ResourceCompletionProposal(final ProposalParameters<? extends AssistInvocationContext> parameters,
 				final IFileStore fileStore, final String explicitName, final String prefix, final IContainer workspaceRef) {
 			super(parameters);
 			this.fileStore= fileStore;
 			this.isDirectory= this.fileStore.fetchInfo().isDirectory();
 			this.workspaceRef= workspaceRef;
 			final StringBuilder name= new StringBuilder((explicitName != null) ? explicitName : this.fileStore.getName());
 			if (prefix != null) {
 				name.insert(0, prefix);
 			}
 			if (this.isDirectory) {
 				name.append(PathCompletionComputor.this.fileSeparator);
 			}
 			this.name= name.toString();
 		}


 		@Override
 		protected String getName() {
 			return this.name;
 		}


 		@Override
 		public String getSortingString() {
 			return this.name;
 		}


 		@Override
 		protected int computeReplacementLength(final int replacementOffset, final Point selection, final int caretOffset, final boolean overwrite) throws BadLocationException {
 			int end= Math.max(caretOffset, selection.x + selection.y);
 			if (overwrite) {
 				final IDocument document= getInvocationContext().getSourceViewer().getDocument();
 				final int length= document.getLength();
 				while (end < length) {
 					final char c= document.getChar(end);
 					if (Character.isLetterOrDigit(c) || c == '_' || c == '.') {
 						end++;
 					}
 					else {
 						break;
 					}
 				}
 				if (end >= length) {
 					end= length;
 				}
 			}
 			return (end - replacementOffset);
 		}


 		@Override
 		public Image getImage() {
 			Image image= null;
 			if (this.workspaceRef != null) {
 				final IResource member= this.workspaceRef.findMember(this.fileStore.getName(), true);
 				if (member != null) {
 					image= LTKUIPlugin.getInstance().getWorkbenchLabelProvider().getImage(member);
 				}
 			}
 			if (image == null) {
 				image= PlatformUI.getWorkbench().getSharedImages().getImage(
 					this.isDirectory ? ISharedImages.IMG_OBJ_FOLDER : ISharedImages.IMG_OBJ_FILE);
 			}
 			return image;
 		}


 		private String getCompletion() {
 			String completion= this.completion;
 			if (completion == null) {
 				final AssistInvocationContext context= getInvocationContext();
 				final IDocument document= context.getDocument();
 				completion= checkPathCompletion(document, getReplacementOffset(), this.name);
 				this.completion= completion;
 			}
 			return completion;
 		}

 		@Override
 		public CharSequence getPrefixCompletionText(final IDocument document, final int completionOffset) {
 			return getCompletion();
 		}

 		@Override
 		protected void doApply(final char trigger, final int stateMask, final int caretOffset,
 				final int replacementOffset, final int replacementLength)
 				throws BadLocationException {
 			final AssistInvocationContext context= getInvocationContext();
 			final IDocument document= context.getDocument();
 			final ApplyData applyData= getApplyData();
 //			final Point selectedRange= viewer.getSelectedRange();

 			final String replacement= getCompletion();
 			final Position newSelectionOffset= new Position(replacementOffset + replacementLength, 0);
 			try {
 				document.addPosition(newSelectionOffset);
 				document.replace(replacementOffset, newSelectionOffset.getOffset() - replacementOffset, replacement);

 				applyData.setSelection(newSelectionOffset.getOffset());
 			}
 			finally {
 				document.removePosition(newSelectionOffset);
 			}

 			if (this.isDirectory) {
 				reinvokeAssist();
 			}
 		}

 	}


 	private int searchMatchRules;

 	private char fileSeparator;
 	private char fileSeparatorBackup;

 	private boolean isWindows;


 	public PathCompletionComputor() {
 	}


 	@Override
 	public void onSessionStarted(final ISourceEditor editor, final ContentAssist assist) {
 		int matchRules= SearchPattern.PREFIX_MATCH;
 		if (assist.getShowSubstringMatches()) {
 			matchRules |= SearchPattern.SUBSTRING_MATCH;
 		}
 		this.searchMatchRules= matchRules;

 		this.isWindows= getIsWindows();
 		this.fileSeparator= getDefaultFileSeparator();
 	}

 	@Override
 	public void onSessionEnded() {
 	}


 	protected int getSearchMatchRules() {
 		return this.searchMatchRules;
 	}

 	protected boolean getIsWindows() {
 		return SystemUtils.getLocalOs() == SystemUtils.OS_WIN;
 	}

 	protected final boolean isWindows() {
 		return this.isWindows;
 	}

 	protected char getDefaultFileSeparator() {
 		return (isWindows()) ? '\\' : '/';
 	}

 	protected char getSegmentSeparator() {
 		return this.fileSeparator;
 	}


 	@Override
 	public void computeCompletionProposals(final AssistInvocationContext context, final int mode,
 			final AssistProposalCollector proposals, final IProgressMonitor monitor) {
 		try {
 			final int offset= context.getInvocationOffset();
 			final TextRegion contentRange= getContentRegion(context, mode);
 			if (contentRange == null
 					|| offset < contentRange.getStartOffset() || offset > contentRange.getEndOffset()) {
 				return;
 			}

 			String prefix= getPrefix(context, contentRange, offset);

 			if (prefix == null) {
 				return;
 			}

 			boolean needSeparatorBeforeStart= false; // including virtual separator
 			String segmentPrefix= ""; //$NON-NLS-1$
 			IFileStore baseStore= null;

 			if (prefix.length() > 0 && prefix.charAt(prefix.length() - 1) == '.') {
 				// prevent that path segments '.' and '..' at end are resolved by Path#canonicalize
 				if (prefix.equals(".") || prefix.endsWith("/.") || (isWindows() && prefix.endsWith("\\."))) { //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					prefix= prefix.substring(0, prefix.length() - 1);
 					segmentPrefix= "."; //$NON-NLS-1$
 				}
 				else if (prefix.equals("..") || prefix.endsWith("/..") || (isWindows() && prefix.endsWith("\\.."))) { // //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 					prefix= prefix.substring(0, prefix.length() - 2);
 					segmentPrefix= ".."; //$NON-NLS-1$
 				}
 			}
 			IPath path= createPath(prefix);
 			if (path == null) {
 				return;
 			}
 			if (path.segmentCount() == 0) {
 				if (isWindows() && path.getDevice() != null && !path.isRoot()) { // C: -> C:/
 					path= path.addTrailingSeparator();
 					needSeparatorBeforeStart= true;
 				}
 			}
 			else if (// path.segmentCount() > 0 &&
 					segmentPrefix.isEmpty() && !path.hasTrailingSeparator()) {
 				segmentPrefix= path.lastSegment();
 				path= path.removeLastSegments(1);
 			}
 			// on Windows, path starting with path separator are relative to the device of current directory
 			if (path.isAbsolute() && isWindows() && path.getDevice() == null && !path.isUNC()) {
 				final IPath basePath= getRelativeBasePath();
 				if (basePath != null) {
 					path= path.setDevice(basePath.getDevice());
 				}
 			}

 			baseStore= resolveStore(path);

 			updatePathSeparator(prefix);

 			String completionPrefix= (needSeparatorBeforeStart) ? Character.toString(this.fileSeparator) : null;

 			if (baseStore == null || !baseStore.fetchInfo().exists()) {
 				tryAlternative(context, path, offset - segmentPrefix.length(), segmentPrefix,
 						completionPrefix, proposals );
 				return;
 			}

 			{	final ProposalParameters<? extends AssistInvocationContext> parameters= createProposalParameters(
 						context, offset - segmentPrefix.length(), segmentPrefix);
 				doAddChildren(parameters, baseStore, completionPrefix, proposals);
 			}
 			if (!segmentPrefix.isEmpty() && !segmentPrefix.equals(".")) { //$NON-NLS-1$
 				baseStore= baseStore.getChild(segmentPrefix);
 				if (baseStore.fetchInfo().exists()) {
 					final StringBuilder prefixBuilder= new StringBuilder();
 					if (completionPrefix != null) {
 						prefixBuilder.append(completionPrefix);
 					}
 					prefixBuilder.append(baseStore.getName());
 					prefixBuilder.append(this.fileSeparator);
 					completionPrefix= prefixBuilder.toString();

 					final ProposalParameters<?> parameters= createProposalParameters(
 							context, offset - segmentPrefix.length(), ""); //$NON-NLS-1$
 					parameters.baseRelevance= 20;
 					doAddChildren(parameters, baseStore, completionPrefix, proposals);
 				}
 			}
 			return;
 		}
 		catch (final BadLocationException e) {
 			StatusManager.getManager().handle(new Status(IStatus.ERROR, SharedUIResources.BUNDLE_ID, -1,
 					"An error occurred while preparing path completions.", e), StatusManager.LOG);
 		}
 		catch (final CoreException e) {
 			StatusManager.getManager().handle(new Status(IStatus.ERROR, SharedUIResources.BUNDLE_ID, -1,
 					"An error occurred while preparing path completions.", e), StatusManager.LOG);
 		}
 		finally {
 			restorePathSeparator();
 		}
 	}

 	@Override
 	public void computeInformationProposals(final AssistInvocationContext context,
 			final AssistProposalCollector proposals, final IProgressMonitor monitor) {
 	}


 	protected @Nullable String getPrefix(final AssistInvocationContext context,
 			final TextRegion contentRegion, final int offset)
 			throws BadLocationException {
 		return checkPrefix(context.getSourceViewer().getDocument().get(
 				contentRegion.getStartOffset(), offset - contentRegion.getStartOffset() ));
 	}

 	/**
 	 * @param prefix to check
 	 * @return the prefix, if valid, otherwise <code>null</code>
 	 */
 	protected @Nullable String checkPrefix(final @Nullable String prefix) {
 		if (prefix == null) {
 			return null;
 		}
 		final char[] breakingChars= "\n\r+<>|?*\"".toCharArray(); //$NON-NLS-1$
 		for (int i= 0; i < breakingChars.length; i++) {
 			if (prefix.indexOf(breakingChars[i]) >= 0) {
 				return null;
 			}
 		}
 		return prefix;
 	}

 	private @Nullable IPath createPath(String s) {
 		if (isWindows() && File.separatorChar == '/') {
 			s= s.replace('\\', '/');
 		}
 		return PathUtils.check(new Path(s));
 	}

 	private void updatePathSeparator(final String prefix) {
 		final int lastBack= prefix.lastIndexOf('\\');
 		final int lastForw= prefix.lastIndexOf('/');
 		if (lastBack > lastForw) {
 			this.fileSeparatorBackup= this.fileSeparator;
 			this.fileSeparator= '\\';
 		}
 		else if (lastForw > lastBack) {
 			this.fileSeparatorBackup= this.fileSeparator;
 			this.fileSeparator= '/';
 		}
 		// else -1 == -1
 	}

 	private void restorePathSeparator() {
 		if (this.fileSeparatorBackup != 0) {
 			this.fileSeparator= this.fileSeparatorBackup;
 			this.fileSeparatorBackup= 0;
 		}
 	}

 	protected ProposalParameters<?> createProposalParameters(
 			final AssistInvocationContext context, final int replacementOffset,
 			final String pattern) {
 		final ProposalParameters<?> parameters= new ProposalParameters<>(
 				context, replacementOffset,
 				new SearchPattern(getSearchMatchRules(), pattern) );
 		parameters.baseRelevance= 20;
 		return parameters;
 	}

 	protected void doAddChildren(final ProposalParameters<? extends AssistInvocationContext> parameters,
 			final IFileStore baseStore,
 			final String completionPrefix,
 			final AssistProposalCollector proposals) throws CoreException {
 		final IContainer[] workspaceRefs= ResourcesPlugin.getWorkspace().getRoot().findContainersForLocationURI(baseStore.toURI());
 		final IContainer workspaceRef= (workspaceRefs.length > 0) ? workspaceRefs[0] : null;
 		final String[] names= baseStore.childNames(EFS.NONE, new NullProgressMonitor());
 		Arrays.sort(names, Collator.getInstance());
 		for (final String name : names) {
 			if (parameters.matchesNamePattern(name)) {
 				proposals.add(new ResourceCompletionProposal(parameters,
 						baseStore.getChild(name), null, completionPrefix,
 						workspaceRef ));
 			}
 		}
 	}


 	protected abstract @Nullable TextRegion getContentRegion(AssistInvocationContext context, int mode)
 			throws BadLocationException;

 	protected @Nullable IPath getRelativeBasePath() {
 		return null;
 	}

 	protected @Nullable IFileStore getRelativeBaseStore() {
 		return null;
 	}

 	protected @Nullable IFileStore resolveStore(IPath path) throws CoreException {
 		if (!path.isAbsolute()) {
 			if (!isWindows() && path.getDevice() == null && "~".equals(path.segment(0))) { //$NON-NLS-1$
 				final IPath homePath= new Path(System.getProperty(SystemUtils.USER_HOME_KEY));
 				path= PathUtils.check(homePath.append(path.removeFirstSegments(1)));
 			}
 			else {
 				final IFileStore base= getRelativeBaseStore();
 				if (base != null) {
 					return base.getFileStore(path);
 				}
 				return null;
 			}
 		}
 		return EFS.getStore(URIUtil.toURI(path));
 	}

 	protected void tryAlternative(final AssistInvocationContext context,
 			final IPath path,
 			final int startOffset, final String segmentPrefix, final @Nullable String completionPrefix,
 			final AssistProposalCollector proposals) throws CoreException {
 	}

 	/**
 	 * Final check of completion string.
 	 *
 	 * E.g. to escape special chars.
 	 *
 	 * @param document
 	 * @param completionOffset
 	 * @param completion
 	 *
 	 * @return the checked completion string
 	 * @throws BadLocationException
 	 */
 	protected String checkPathCompletion(final IDocument document, final int completionOffset,
 			final String completion) {
 		return completion;
 	}

 }
	/*=============================================================================#
	# Copyright (c) 2007, 2020 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.ltk.ui.sourceediting.assist;

	import java.io.File;
	import java.util.Arrays;

	import com.ibm.icu.text.Collator;

	import org.eclipse.core.filesystem.EFS;
	import org.eclipse.core.filesystem.IFileStore;
	import org.eclipse.core.filesystem.URIUtil;
	import org.eclipse.core.resources.IContainer;
	import org.eclipse.core.resources.IResource;
	import org.eclipse.core.resources.ResourcesPlugin;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.NullProgressMonitor;
	import org.eclipse.core.runtime.Path;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.IDocument;
	import org.eclipse.jface.text.Position;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.ui.ISharedImages;
	import org.eclipse.ui.PlatformUI;
	import org.eclipse.ui.statushandlers.StatusManager;

	import org.eclipse.statet.jcommons.lang.NonNullByDefault;
	import org.eclipse.statet.jcommons.lang.Nullable;
	import org.eclipse.statet.jcommons.lang.SystemUtils;
	import org.eclipse.statet.jcommons.text.core.SearchPattern;
	import org.eclipse.statet.jcommons.text.core.TextRegion;

	import org.eclipse.statet.ecommons.runtime.core.util.PathUtils;
	import org.eclipse.statet.ecommons.ui.SharedUIResources;

	import org.eclipse.statet.internal.ltk.ui.LTKUIPlugin;
	import org.eclipse.statet.ltk.ui.sourceediting.ISourceEditor;
	import org.eclipse.statet.ltk.ui.sourceediting.assist.SourceProposal.ProposalParameters;


	/**
	* Content assist processor for completion of path for local file system resources.
	*/
	@NonNullByDefault
	public abstract class PathCompletionComputor implements ContentAssistComputer {


	protected class ResourceCompletionProposal extends SourceProposal<AssistInvocationContext> {

	private final IFileStore fileStore;
	private final boolean isDirectory;
	/** The parent in the workspace, if in workspace */
	private final IContainer workspaceRef;

	private final String name;

	/** Final completion string */
	private @Nullable String completion;


	/**
	* Creates a new completion proposal for a resource
	*
	* @param offset the offset in the document where to insert the completion
	* @param fileStore the EFS resource handle
	* @param explicitName optional explicit name used instead of the name of the fileStore
	* @param prefix optional prefix to prefix before the name
	* @param workspaceRef the workspace resource handle, if the resource is in the workspace
	*/
	public ResourceCompletionProposal(final ProposalParameters<? extends AssistInvocationContext> parameters,
	final IFileStore fileStore, final String explicitName, final String prefix, final IContainer workspaceRef) {
	super(parameters);
	this.fileStore= fileStore;
	this.isDirectory= this.fileStore.fetchInfo().isDirectory();
	this.workspaceRef= workspaceRef;
	final StringBuilder name= new StringBuilder((explicitName != null) ? explicitName : this.fileStore.getName());
	if (prefix != null) {
	name.insert(0, prefix);
	}
	if (this.isDirectory) {
	name.append(PathCompletionComputor.this.fileSeparator);
	}
	this.name= name.toString();
	}


	@Override
	protected String getName() {
	return this.name;
	}


	@Override
	public String getSortingString() {
	return this.name;
	}


	@Override
	protected int computeReplacementLength(final int replacementOffset, final Point selection, final int caretOffset, final boolean overwrite) throws BadLocationException {
	int end= Math.max(caretOffset, selection.x + selection.y);
	if (overwrite) {
	final IDocument document= getInvocationContext().getSourceViewer().getDocument();
	final int length= document.getLength();
	while (end < length) {
	final char c= document.getChar(end);
	if (Character.isLetterOrDigit(c) \|\| c == '_' \|\| c == '.') {
	end++;
	}
	else {
	break;
	}
	}
	if (end >= length) {
	end= length;
	}
	}
	return (end - replacementOffset);
	}


	@Override
	public Image getImage() {
	Image image= null;
	if (this.workspaceRef != null) {
	final IResource member= this.workspaceRef.findMember(this.fileStore.getName(), true);
	if (member != null) {
	image= LTKUIPlugin.getInstance().getWorkbenchLabelProvider().getImage(member);
	}
	}
	if (image == null) {
	image= PlatformUI.getWorkbench().getSharedImages().getImage(
	this.isDirectory ? ISharedImages.IMG_OBJ_FOLDER : ISharedImages.IMG_OBJ_FILE);
	}
	return image;
	}


	private String getCompletion() {
	String completion= this.completion;
	if (completion == null) {
	final AssistInvocationContext context= getInvocationContext();
	final IDocument document= context.getDocument();
	completion= checkPathCompletion(document, getReplacementOffset(), this.name);
	this.completion= completion;
	}
	return completion;
	}

	@Override
	public CharSequence getPrefixCompletionText(final IDocument document, final int completionOffset) {
	return getCompletion();
	}

	@Override
	protected void doApply(final char trigger, final int stateMask, final int caretOffset,
	final int replacementOffset, final int replacementLength)
	throws BadLocationException {
	final AssistInvocationContext context= getInvocationContext();
	final IDocument document= context.getDocument();
	final ApplyData applyData= getApplyData();
	// final Point selectedRange= viewer.getSelectedRange();

	final String replacement= getCompletion();
	final Position newSelectionOffset= new Position(replacementOffset + replacementLength, 0);
	try {
	document.addPosition(newSelectionOffset);
	document.replace(replacementOffset, newSelectionOffset.getOffset() - replacementOffset, replacement);

	applyData.setSelection(newSelectionOffset.getOffset());
	}
	finally {
	document.removePosition(newSelectionOffset);
	}

	if (this.isDirectory) {
	reinvokeAssist();
	}
	}

	}


	private int searchMatchRules;

	private char fileSeparator;
	private char fileSeparatorBackup;

	private boolean isWindows;


	public PathCompletionComputor() {
	}


	@Override
	public void onSessionStarted(final ISourceEditor editor, final ContentAssist assist) {
	int matchRules= SearchPattern.PREFIX_MATCH;
	if (assist.getShowSubstringMatches()) {
	matchRules \|= SearchPattern.SUBSTRING_MATCH;
	}
	this.searchMatchRules= matchRules;

	this.isWindows= getIsWindows();
	this.fileSeparator= getDefaultFileSeparator();
	}

	@Override
	public void onSessionEnded() {
	}


	protected int getSearchMatchRules() {
	return this.searchMatchRules;
	}

	protected boolean getIsWindows() {
	return SystemUtils.getLocalOs() == SystemUtils.OS_WIN;
	}

	protected final boolean isWindows() {
	return this.isWindows;
	}

	protected char getDefaultFileSeparator() {
	return (isWindows()) ? '\\' : '/';
	}

	protected char getSegmentSeparator() {
	return this.fileSeparator;
	}


	@Override
	public void computeCompletionProposals(final AssistInvocationContext context, final int mode,
	final AssistProposalCollector proposals, final IProgressMonitor monitor) {
	try {
	final int offset= context.getInvocationOffset();
	final TextRegion contentRange= getContentRegion(context, mode);
	if (contentRange == null
	\|\| offset < contentRange.getStartOffset() \|\| offset > contentRange.getEndOffset()) {
	return;
	}

	String prefix= getPrefix(context, contentRange, offset);

	if (prefix == null) {
	return;
	}

	boolean needSeparatorBeforeStart= false; // including virtual separator
	String segmentPrefix= ""; //$NON-NLS-1$
	IFileStore baseStore= null;

	if (prefix.length() > 0 && prefix.charAt(prefix.length() - 1) == '.') {
	// prevent that path segments '.' and '..' at end are resolved by Path#canonicalize
	if (prefix.equals(".") \|\| prefix.endsWith("/.") \|\| (isWindows() && prefix.endsWith("\\."))) { //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	prefix= prefix.substring(0, prefix.length() - 1);
	segmentPrefix= "."; //$NON-NLS-1$
	}
	else if (prefix.equals("..") \|\| prefix.endsWith("/..") \|\| (isWindows() && prefix.endsWith("\\.."))) { // //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	prefix= prefix.substring(0, prefix.length() - 2);
	segmentPrefix= ".."; //$NON-NLS-1$
	}
	}
	IPath path= createPath(prefix);
	if (path == null) {
	return;
	}
	if (path.segmentCount() == 0) {
	if (isWindows() && path.getDevice() != null && !path.isRoot()) { // C: -> C:/
	path= path.addTrailingSeparator();
	needSeparatorBeforeStart= true;
	}
	}
	else if (// path.segmentCount() > 0 &&
	segmentPrefix.isEmpty() && !path.hasTrailingSeparator()) {
	segmentPrefix= path.lastSegment();
	path= path.removeLastSegments(1);
	}
	// on Windows, path starting with path separator are relative to the device of current directory
	if (path.isAbsolute() && isWindows() && path.getDevice() == null && !path.isUNC()) {
	final IPath basePath= getRelativeBasePath();
	if (basePath != null) {
	path= path.setDevice(basePath.getDevice());
	}
	}

	baseStore= resolveStore(path);

	updatePathSeparator(prefix);

	String completionPrefix= (needSeparatorBeforeStart) ? Character.toString(this.fileSeparator) : null;

	if (baseStore == null \|\| !baseStore.fetchInfo().exists()) {
	tryAlternative(context, path, offset - segmentPrefix.length(), segmentPrefix,
	completionPrefix, proposals );
	return;
	}

	{ final ProposalParameters<? extends AssistInvocationContext> parameters= createProposalParameters(
	context, offset - segmentPrefix.length(), segmentPrefix);
	doAddChildren(parameters, baseStore, completionPrefix, proposals);
	}
	if (!segmentPrefix.isEmpty() && !segmentPrefix.equals(".")) { //$NON-NLS-1$
	baseStore= baseStore.getChild(segmentPrefix);
	if (baseStore.fetchInfo().exists()) {
	final StringBuilder prefixBuilder= new StringBuilder();
	if (completionPrefix != null) {
	prefixBuilder.append(completionPrefix);
	}
	prefixBuilder.append(baseStore.getName());
	prefixBuilder.append(this.fileSeparator);
	completionPrefix= prefixBuilder.toString();

	final ProposalParameters<?> parameters= createProposalParameters(
	context, offset - segmentPrefix.length(), ""); //$NON-NLS-1$
	parameters.baseRelevance= 20;
	doAddChildren(parameters, baseStore, completionPrefix, proposals);
	}
	}
	return;
	}
	catch (final BadLocationException e) {
	StatusManager.getManager().handle(new Status(IStatus.ERROR, SharedUIResources.BUNDLE_ID, -1,
	"An error occurred while preparing path completions.", e), StatusManager.LOG);
	}
	catch (final CoreException e) {
	StatusManager.getManager().handle(new Status(IStatus.ERROR, SharedUIResources.BUNDLE_ID, -1,
	"An error occurred while preparing path completions.", e), StatusManager.LOG);
	}
	finally {
	restorePathSeparator();
	}
	}

	@Override
	public void computeInformationProposals(final AssistInvocationContext context,
	final AssistProposalCollector proposals, final IProgressMonitor monitor) {
	}


	protected @Nullable String getPrefix(final AssistInvocationContext context,
	final TextRegion contentRegion, final int offset)
	throws BadLocationException {
	return checkPrefix(context.getSourceViewer().getDocument().get(
	contentRegion.getStartOffset(), offset - contentRegion.getStartOffset() ));
	}

	/**
	* @param prefix to check
	* @return the prefix, if valid, otherwise <code>null</code>
	*/
	protected @Nullable String checkPrefix(final @Nullable String prefix) {
	if (prefix == null) {
	return null;
	}
	final char[] breakingChars= "\n\r+<>\|?*\"".toCharArray(); //$NON-NLS-1$
	for (int i= 0; i < breakingChars.length; i++) {
	if (prefix.indexOf(breakingChars[i]) >= 0) {
	return null;
	}
	}
	return prefix;
	}

	private @Nullable IPath createPath(String s) {
	if (isWindows() && File.separatorChar == '/') {
	s= s.replace('\\', '/');
	}
	return PathUtils.check(new Path(s));
	}

	private void updatePathSeparator(final String prefix) {
	final int lastBack= prefix.lastIndexOf('\\');
	final int lastForw= prefix.lastIndexOf('/');
	if (lastBack > lastForw) {
	this.fileSeparatorBackup= this.fileSeparator;
	this.fileSeparator= '\\';
	}
	else if (lastForw > lastBack) {
	this.fileSeparatorBackup= this.fileSeparator;
	this.fileSeparator= '/';
	}
	// else -1 == -1
	}

	private void restorePathSeparator() {
	if (this.fileSeparatorBackup != 0) {
	this.fileSeparator= this.fileSeparatorBackup;
	this.fileSeparatorBackup= 0;
	}
	}

	protected ProposalParameters<?> createProposalParameters(
	final AssistInvocationContext context, final int replacementOffset,
	final String pattern) {
	final ProposalParameters<?> parameters= new ProposalParameters<>(
	context, replacementOffset,
	new SearchPattern(getSearchMatchRules(), pattern) );
	parameters.baseRelevance= 20;
	return parameters;
	}

	protected void doAddChildren(final ProposalParameters<? extends AssistInvocationContext> parameters,
	final IFileStore baseStore,
	final String completionPrefix,
	final AssistProposalCollector proposals) throws CoreException {
	final IContainer[] workspaceRefs= ResourcesPlugin.getWorkspace().getRoot().findContainersForLocationURI(baseStore.toURI());
	final IContainer workspaceRef= (workspaceRefs.length > 0) ? workspaceRefs[0] : null;
	final String[] names= baseStore.childNames(EFS.NONE, new NullProgressMonitor());
	Arrays.sort(names, Collator.getInstance());
	for (final String name : names) {
	if (parameters.matchesNamePattern(name)) {
	proposals.add(new ResourceCompletionProposal(parameters,
	baseStore.getChild(name), null, completionPrefix,
	workspaceRef ));
	}
	}
	}


	protected abstract @Nullable TextRegion getContentRegion(AssistInvocationContext context, int mode)
	throws BadLocationException;

	protected @Nullable IPath getRelativeBasePath() {
	return null;
	}

	protected @Nullable IFileStore getRelativeBaseStore() {
	return null;
	}

	protected @Nullable IFileStore resolveStore(IPath path) throws CoreException {
	if (!path.isAbsolute()) {
	if (!isWindows() && path.getDevice() == null && "~".equals(path.segment(0))) { //$NON-NLS-1$
	final IPath homePath= new Path(System.getProperty(SystemUtils.USER_HOME_KEY));
	path= PathUtils.check(homePath.append(path.removeFirstSegments(1)));
	}
	else {
	final IFileStore base= getRelativeBaseStore();
	if (base != null) {
	return base.getFileStore(path);
	}
	return null;
	}
	}
	return EFS.getStore(URIUtil.toURI(path));
	}

	protected void tryAlternative(final AssistInvocationContext context,
	final IPath path,
	final int startOffset, final String segmentPrefix, final @Nullable String completionPrefix,
	final AssistProposalCollector proposals) throws CoreException {
	}

	/**
	* Final check of completion string.
	*
	* E.g. to escape special chars.
	*
	* @param document
	* @param completionOffset
	* @param completion
	*
	* @return the checked completion string
	* @throws BadLocationException
	*/
	protected String checkPathCompletion(final IDocument document, final int completionOffset,
	final String completion) {
	return completion;
	}

	}