Copyright (c) 2000, 2015 IBM Corporation 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:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.filebuffers.manipulation;

import java.util.Map;

import org.eclipse.core.internal.filebuffers.FileBuffersPlugin;
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.OperationCanceledException;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.SubMonitor;

import org.eclipse.core.filebuffers.IFileBuffer;
import org.eclipse.core.filebuffers.IFileBufferStatusCodes;
import org.eclipse.core.filebuffers.ITextFileBuffer;

import org.eclipse.text.edits.TextEdit;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DocumentRewriteSession;
import org.eclipse.jface.text.DocumentRewriteSessionType;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IDocumentExtension4;
import org.eclipse.jface.text.IDocumentPartitioner;
import org.eclipse.jface.text.TextUtilities;

Abstraction for a file buffer operation that works on text file buffers.
Subclasses have to override the computeTextEdits method in order to provide a sequence of TextEdit objects. 
Since:
3.1/**
 * Abstraction for a file buffer operation that works on text file buffers.
 * Subclasses have to override the <code>computeTextEdits</code> method in
 * order to provide a sequence of {@link org.eclipse.text.edits.TextEdit}
 * objects.
 *
 * @since 3.1
 */
public abstract class TextFileBufferOperation implements IFileBufferOperation {


	
Computes and returns a text edit. Subclasses have to provide that method.
Params:
textFileBuffer – the text file buffer to manipulate
progressMonitor – the progress monitor
Throws:
CoreException – in case the computation failed
OperationCanceledException – in case the progress monitor has been set to canceled
Returns:
the text edits describing the content manipulation/**
	 * Computes and returns a text edit. Subclasses have to provide that method.
	 *
	 * @param textFileBuffer the text file buffer to manipulate
	 * @param progressMonitor the progress monitor
	 * @return the text edits describing the content manipulation
	 * @throws CoreException in case the computation failed
	 * @throws OperationCanceledException in case the progress monitor has been set to canceled
	 */
	protected abstract MultiTextEditWithProgress computeTextEdit(ITextFileBuffer textFileBuffer, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException;

	
Returns the rewrite session type that corresponds to the text edit sequence.
Returns:
the rewrite session type/**
	 * Returns the rewrite session type that corresponds to the text edit sequence.
	 *
	 * @return the rewrite session type
	 */
	protected abstract DocumentRewriteSessionType getDocumentRewriteSessionType();


	private String fOperationName;
	private DocumentRewriteSession fDocumentRewriteSession;

	
Creates a new operation with the given name.
Params:
operationName – the name of the operation/**
	 * Creates a new operation with the given name.
	 *
	 * @param operationName the name of the operation
	 */
	protected TextFileBufferOperation(String operationName) {
		fOperationName= operationName;
	}

	@Override
	public String getOperationName() {
		return fOperationName;
	}

	@Override
	public void run(IFileBuffer fileBuffer, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException {

		if (fileBuffer instanceof ITextFileBuffer) {
			ITextFileBuffer textFileBuffer= (ITextFileBuffer) fileBuffer;
			IPath path= textFileBuffer.getLocation();
			String taskName= path == null ? getOperationName() : path.lastSegment();
			SubMonitor subMonitor= SubMonitor.convert(progressMonitor, taskName, 100);
			MultiTextEditWithProgress edit= computeTextEdit(textFileBuffer, subMonitor.split(10));
			if (edit != null) {
				Map<String, IDocumentPartitioner> stateData= startRewriteSession(textFileBuffer);
				try {
					applyTextEdit(textFileBuffer, edit, subMonitor.split(90));
				} finally {
					stopRewriteSession(textFileBuffer, stateData);
				}
			}
		}
	}

	private Map<String, IDocumentPartitioner> startRewriteSession(ITextFileBuffer fileBuffer) {
		Map<String, IDocumentPartitioner> stateData= null;

		IDocument document= fileBuffer.getDocument();
		if (document instanceof IDocumentExtension4) {
			IDocumentExtension4 extension= (IDocumentExtension4) document;
			fDocumentRewriteSession= extension.startRewriteSession(getDocumentRewriteSessionType());
		} else
			stateData= TextUtilities.removeDocumentPartitioners(document);

		return stateData;
	}

	private void stopRewriteSession(ITextFileBuffer fileBuffer, Map<String, IDocumentPartitioner> stateData) {
		IDocument document= fileBuffer.getDocument();
		if (document instanceof IDocumentExtension4) {
			IDocumentExtension4 extension= (IDocumentExtension4) document;
			extension.stopRewriteSession(fDocumentRewriteSession);
			fDocumentRewriteSession= null;
		} else if (stateData != null)
			TextUtilities.addDocumentPartitioners(document, stateData);
	}

	private void applyTextEdit(ITextFileBuffer fileBuffer, MultiTextEditWithProgress textEdit, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException {
		try {
			textEdit.apply(fileBuffer.getDocument(), TextEdit.NONE, progressMonitor);
		} catch (BadLocationException x) {
			throw new CoreException(new Status(IStatus.ERROR, FileBuffersPlugin.PLUGIN_ID, IFileBufferStatusCodes.CONTENT_CHANGE_FAILED, "", x)); //$NON-NLS-1$
		}
	}
}