Copyright (c) 2000, 2008 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, 2008 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.internal.filebuffers;

import org.eclipse.core.filesystem.EFS;
import org.eclipse.core.filesystem.IFileInfo;
import org.eclipse.core.filesystem.IFileStore;
import org.eclipse.core.filesystem.URIUtil;

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.jobs.ISchedulingRule;

import org.eclipse.jface.text.IDocumentExtension4;

Since:
3.3 (previously available as JavaFileBuffer since 3.0)/**
 * @since 3.3 (previously available as JavaFileBuffer since 3.0)
 */
public abstract class FileStoreFileBuffer extends AbstractFileBuffer  {

	
The location /** The location */
	protected IPath fLocation;
	
How often the element has been connected /** How often the element has been connected */
	protected int fReferenceCount;
	
Can the element be saved /** Can the element be saved */
	protected boolean fCanBeSaved= false;
	
The status of this element /** The status of this element */
	protected IStatus fStatus;
	
The time stamp at which this buffer synchronized with the underlying file. /** The time stamp at which this buffer synchronized with the underlying file. */
	protected long fSynchronizationStamp= IDocumentExtension4.UNKNOWN_MODIFICATION_STAMP;
	
How often the synchronization context has been requested /** How often the synchronization context has been requested */
	protected int fSynchronizationContextCount;


	public FileStoreFileBuffer(TextFileBufferManager manager) {
		super(manager);
	}

	abstract protected void addFileBufferContentListeners();

	abstract protected void removeFileBufferContentListeners();

	abstract protected void initializeFileBufferContent(IProgressMonitor monitor) throws CoreException;

	abstract protected void commitFileBufferContent(IProgressMonitor monitor, boolean overwrite) throws CoreException;

	public void create(IFileStore fileStore, IProgressMonitor monitor) throws CoreException {
		IFileInfo info= fileStore.fetchInfo();
		fFileStore= fileStore;
		if (fLocation == null)
			fLocation= URIUtil.toPath(fileStore.toURI());

		initializeFileBufferContent(monitor);
		if (info.exists())
			fSynchronizationStamp= info.getLastModified();

		addFileBufferContentListeners();
	}

	@Override
	public void create(IPath location, IProgressMonitor monitor) throws CoreException {
		fLocation= location;
		create(EFS.getStore(URIUtil.toURI(getLocation())), monitor);
	}

	@Override
	public void connect() {
		++ fReferenceCount;
		if (fReferenceCount == 1)
			connected();
	}

	
Called when this file buffer has been connected. This is the case when
there is exactly one connection.

Clients may extend this method.
/**
	 * Called when this file buffer has been connected. This is the case when
	 * there is exactly one connection.
	 * <p>
	 * Clients may extend this method.
	 */
	protected void connected() {
	}

	@Override
	public void disconnect() throws CoreException {
		--fReferenceCount;
		if (fReferenceCount <= 0)
			disconnected();
	}

	
Called when this file buffer has been disconnected. This is the case when
the number of connections drops below 1.

Clients may extend this method.
/**
	 * Called when this file buffer has been disconnected. This is the case when
	 * the number of connections drops below <code>1</code>.
	 * <p>
	 * Clients may extend this method.
	 */
	protected void disconnected() {
	}

	@Override
	protected boolean isDisconnected() {
		return fReferenceCount <= 0;
	}

	@Override
	public IPath getLocation() {
		return fLocation;
	}

	@Override
	public void commit(IProgressMonitor monitor, boolean overwrite) throws CoreException {
		if (!isDisconnected() && fCanBeSaved) {

			fManager.fireStateChanging(this);

			try {
				commitFileBufferContent(monitor, overwrite);
			} catch (CoreException | RuntimeException x) {
				fManager.fireStateChangeFailed(this);
				throw x;
			}

			fCanBeSaved= false;
			addFileBufferContentListeners();
			fManager.fireDirtyStateChanged(this, fCanBeSaved);
		}
	}

	@Override
	public ISchedulingRule computeCommitRule() {
		return null;
	}

	@Override
	public boolean isDirty() {
		return fCanBeSaved;
	}

	@Override
	public void setDirty(boolean isDirty) {
		fCanBeSaved= isDirty;
	}

	@Override
	public boolean isShared() {
		return fReferenceCount > 1;
	}

	@Override
	public ISchedulingRule computeValidateStateRule() {
		return null;
	}

	@Override
	public void validateState(IProgressMonitor monitor, Object computationContext) throws CoreException {
		// nop
	}

	@Override
	public boolean isStateValidated() {
		return true;
	}

	@Override
	public void resetStateValidation() {
		// nop
	}

	@Override
	public boolean isSynchronized() {
		return fSynchronizationStamp == getModificationStamp();
	}

	@Override
	public void requestSynchronizationContext() {
		++ fSynchronizationContextCount;
	}

	@Override
	public void releaseSynchronizationContext() {
		-- fSynchronizationContextCount;
	}

	@Override
	public boolean isSynchronizationContextRequested() {
		return fSynchronizationContextCount > 0;
	}

	@Override
	public boolean isCommitable() {
		IFileInfo info= fFileStore.fetchInfo();
		return info.exists() && !info.getAttribute(EFS.ATTRIBUTE_READ_ONLY);
	}

	@Override
	public void validationStateChanged(boolean validationState, IStatus status) {
		//nop
	}
}