[FS] Use InputStream.transferTo() instead of custom transfers

This reduces the amount of code and can also improve the performance,
depending on the type of the source and target stream.
For example, since Java-18, if an 'FileInputStream' is transfered to an
'FileOutputStream' the copying is performed using FileChannels, which is
faster than just the plain read and write of the content bytes.

The only drawback of the new implementation is that precise
progress-reporting is not possible anymore. But before it wasn't
properly done anyways.

Author: HannesWell

resources/bundles/org.eclipse.core.filesystem/src/org/eclipse/core/filesystem/provider/FileStore.java

@@ -54,45 +54,6 @@ public abstract class FileStore extends PlatformObject implements IFileStore {
 	 */
 	protected static final String[] EMPTY_STRING_ARRAY = {};
 
-	/**
-	 * Transfers the contents of an input stream to an output stream, using a large
-	 * buffer.
-	 *
-	 * @param source The input stream to transfer
-	 * @param destination The destination stream of the transfer
-	 * @param length the size of the file or -1 if not known
-	 * @param path A path representing the data being transferred for use in error
-	 * messages.
-	 * @param monitor A progress monitor
-	 */
-	private static final void transferStreams(InputStream source, OutputStream destination, long length, String path, IProgressMonitor monitor) throws CoreException {
-		byte[] buffer = new byte[8192];
-		SubMonitor subMonitor = SubMonitor.convert(monitor, length >= 0 ? 1 + (int) (length / buffer.length) : 1000);
-		try (source; destination) {
-			while (true) {
-				int bytesRead = -1;
-				try {
-					bytesRead = source.read(buffer);
-				} catch (IOException e) {
-					String msg = NLS.bind(Messages.failedReadDuringWrite, path);
-					Policy.error(EFS.ERROR_READ, msg, e);
-				}
-				try {
-					if (bytesRead == -1) {
-						destination.close();
-						break;
-					}
-					destination.write(buffer, 0, bytesRead);
-				} catch (IOException e) {
-					String msg = NLS.bind(Messages.couldNotWrite, path);
-					Policy.error(EFS.ERROR_WRITE, msg, e);
-				}
-				subMonitor.worked(1);
-			}
-		} catch (IOException e) { // ignore
-		}
-	}
-
 	/**
 	 * The default implementation of {@link IFileStore#childInfos(int, IProgressMonitor)}.
 	 * Subclasses should override this method where a more efficient implementation
@@ -197,17 +158,19 @@ protected void copyDirectory(IFileInfo sourceInfo, IFileStore destination, int o
 	 * </ul>
 	 */
 	protected void copyFile(IFileInfo sourceInfo, IFileStore destination, int options, IProgressMonitor monitor) throws CoreException {
-		if ((options & EFS.OVERWRITE) == 0 && destination.fetchInfo().exists())
+		if ((options & EFS.OVERWRITE) == 0 && destination.fetchInfo().exists()) {
 			Policy.error(EFS.ERROR_EXISTS, NLS.bind(Messages.fileExists, destination));
-		long length = sourceInfo.getLength();
+		}
 		String sourcePath = toString();
 		SubMonitor subMonitor = SubMonitor.convert(monitor, NLS.bind(Messages.copying, sourcePath), 100);
 		try (InputStream in = openInputStream(EFS.NONE, subMonitor.newChild(1)); //
 				OutputStream out = destination.openOutputStream(EFS.NONE, subMonitor.newChild(1));) {
-			transferStreams(in, out, length, sourcePath, subMonitor.newChild(98));
+			in.transferTo(out);
+			subMonitor.worked(93);
 			transferAttributes(sourceInfo, destination);
+			subMonitor.worked(5);
 		} catch (IOException e) {
-			// ignore
+			Policy.error(EFS.ERROR_WRITE, NLS.bind(Messages.failedCopy, sourcePath), e);
 		} catch (CoreException e) {
 			//if we failed to write, try to cleanup the half written file
 			if (!destination.fetchInfo(0, null).exists())

resources/bundles/org.eclipse.core.filesystem/src/org/eclipse/core/internal/filesystem/Messages.java

@@ -34,7 +34,6 @@ public class Messages extends NLS {
 	public static String failedCreateAccessDenied;
 	public static String failedMove;
 	public static String failedCopy;
-	public static String failedReadDuringWrite;
 	public static String fileExists;
 	public static String fileNotFound;
 	public static String moving;

resources/bundles/org.eclipse.core.filesystem/src/org/eclipse/core/internal/filesystem/messages.properties

@@ -26,7 +26,6 @@ failedCreateAccessDenied=Cannot create file, access denied: {0}.
 failedCreateWrongType=Cannot create file because existing file of wrong type exists: {0}.
 failedMove = Critical failure moving '{0}' to '{1}'. Content is lost.
 failedCopy = Could not copy file '{0}' to '{1}'.
-failedReadDuringWrite = Could not read from source when writing file: {0}
 fileExists = File already exists on disk: {0}.
 fileNotFound = File not found: {0}.
 moving = Moving: {0}.

resources/bundles/org.eclipse.core.resources/src/org/eclipse/core/internal/localstore/FileSystemResourceManager.java

@@ -1204,7 +1204,7 @@ public void updateLocalSync(ResourceInfo info, long localSyncInfo) {
 	 * @see IResource#KEEP_HISTORY
 	 */
 	public void write(IFile target, InputStream content, IFileInfo fileInfo, int updateFlags, boolean append, IProgressMonitor monitor) throws CoreException {
-		SubMonitor subMonitor = SubMonitor.convert(monitor, 4);
+		SubMonitor subMonitor = SubMonitor.convert(monitor, 100);
 		try (content) {
 			Resource targetResource = (Resource) target;
 			IFileStore store = getStore(target);
@@ -1215,7 +1215,8 @@ public void write(IFile target, InputStream content, IFileInfo fileInfo, int upd
 				boolean opened = false;
 				try (OutputStream out = store.openOutputStream(options, subMonitor.split(1))) {
 					opened = true;
-					FileUtil.transferStreams(content, out, store.toString(), subMonitor.split(1));
+					content.transferTo(out);
+					subMonitor.worked(95);
 				} catch (CoreException e) {
 					// On Windows an attempt to open an output stream on a hidden file results in
 					// FileNotFoundException.
@@ -1231,19 +1232,20 @@ public void write(IFile target, InputStream content, IFileInfo fileInfo, int upd
 					// set hidden=false and retry:
 					fileInfo.setAttribute(EFS.ATTRIBUTE_HIDDEN, false);
 					store.putInfo(fileInfo, EFS.SET_ATTRIBUTES, subMonitor.split(1));
-					try (OutputStream out = store.openOutputStream(options, null)) {
+					try (OutputStream out = store.openOutputStream(options, subMonitor.split(1))) {
 						// restore Hidden Attribute:
 						fileInfo.setAttribute(EFS.ATTRIBUTE_HIDDEN, true);
 						store.putInfo(fileInfo, EFS.SET_ATTRIBUTES, subMonitor.split(1));
-						FileUtil.transferStreams(content, out, store.toString(), subMonitor.split(1));
+						content.transferTo(out);
+						subMonitor.worked(92);
 					}
 				}
 			} catch (IOException e) {
-				// Exception on OutputStream.close()
 				String msg = NLS.bind(Messages.localstore_couldNotWrite, store.toString());
 				throw new ResourceException(IResourceStatus.FAILED_WRITE_LOCAL, IPath.fromOSString(store.toString()), msg, e);
 			}
 			finishWrite(targetResource, store);
+			subMonitor.worked(4);
 		} catch (IOException streamCloseIgnored) {
 			// ignore Exception on InputStream.close()
 		}

resources/bundles/org.eclipse.core.resources/src/org/eclipse/core/internal/utils/FileUtil.java

@@ -16,10 +16,7 @@
  *******************************************************************************/
 package org.eclipse.core.internal.utils;
 
-import java.io.ByteArrayInputStream;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
@@ -31,18 +28,13 @@
 import org.eclipse.core.filesystem.IFileStore;
 import org.eclipse.core.filesystem.IFileSystem;
 import org.eclipse.core.filesystem.URIUtil;
-import org.eclipse.core.internal.resources.ResourceException;
 import org.eclipse.core.internal.resources.Workspace;
 import org.eclipse.core.resources.IFile;
-import org.eclipse.core.resources.IResourceStatus;
 import org.eclipse.core.resources.ResourceAttributes;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
-import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.Platform;
-import org.eclipse.core.runtime.SubMonitor;
 import org.eclipse.core.runtime.content.IContentDescription;
-import org.eclipse.osgi.util.NLS;
 
 /**
  * Static utility methods for manipulating Files and URIs.
@@ -306,39 +298,6 @@ public static IPath toPath(URI uri) {
 		return null;
 	}
 
-	public static final void transferStreams(InputStream source, OutputStream destination, String path,
-			IProgressMonitor monitor) throws CoreException {
-		SubMonitor subMonitor = SubMonitor.convert(monitor);
-		try (source) {
-			try (destination) {
-				if (source instanceof ByteArrayInputStream) {
-					// ByteArrayInputStream does overload transferTo avoiding buffering
-					((ByteArrayInputStream) source).transferTo(destination);
-					subMonitor.split(1);
-				} else {
-					byte[] buffer = new byte[8192];
-					while (true) {
-						int bytesRead = -1;
-						try {
-							bytesRead = source.read(buffer);
-						} catch (IOException e) {
-							String msg = NLS.bind(Messages.localstore_failedReadDuringWrite, path);
-							throw new ResourceException(IResourceStatus.FAILED_READ_LOCAL, IPath.fromOSString(path), msg, e);
-						}
-						if (bytesRead == -1) {
-							break;
-						}
-						destination.write(buffer, 0, bytesRead);
-						subMonitor.split(1);
-					}
-				}
-			}
-		} catch (IOException e) {
-			String msg = NLS.bind(Messages.localstore_couldNotWrite, path);
-			throw new ResourceException(IResourceStatus.FAILED_WRITE_LOCAL, IPath.fromOSString(path), msg, e);
-		}
-	}
-
 	public static char[] readAllChars(IFile file) throws CoreException {
 		byte[] content = file.readAllBytes();
 		Charset charset = getCharset(file, content);