org.aspectj.ajde/source/org/aspectj/org/eclipse/jdt/internal/core/nd/java/FileFingerprint.java - ajdt/org.eclipse.ajdt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2015, 2016 Google, Inc 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
  *
  * Contributors:
  *   Stefan Xenos (Google) - Initial implementation
  *******************************************************************************/
 package org.aspectj.org.eclipse.jdt.internal.core.nd.java;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;

 import org.eclipse.core.filesystem.EFS;
 import org.eclipse.core.filesystem.IFileInfo;
 import org.eclipse.core.filesystem.IFileStore;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.SubMonitor;
 import org.aspectj.org.eclipse.jdt.internal.core.nd.StreamHasher;

 public class FileFingerprint {
 	/**
 	 * Sentinel value for {@link #time} indicating a nonexistent fingerprint. This is used for the timestamp of
 	 * nonexistent files and for the {@link #getEmpty()} singleton.
 	 */
 	public static final long NEVER_MODIFIED = 0;

 	/**
 	 * Sentinel value for {@link #time} indicating that the timestamp was not recorded as part of the fingerprint.
 	 * This is normally used to indicate that the file's timestamp was so close to the current system time at the time
 	 * the fingerprint was computed that subsequent changes in the file might not be detected. In such cases, timestamps
 	 * are an unreliable method for determining if the file has changed and so are not included as part of the fingerprint.
 	 */
 	public static final long UNKNOWN = 1;

 	/**
 	 * Worst-case accuracy of filesystem timestamps, among all supported platforms (this is currently 1s on linux, 2s on
 	 * FAT systems).
 	 */
 	private static final long WORST_FILESYSTEM_TIMESTAMP_ACCURACY_MS = 2000;

 	private long time;
 	private long hash;
 	private long size;

 	private static final FileFingerprint EMPTY = new FileFingerprint(NEVER_MODIFIED,0,0);

 	public static final FileFingerprint getEmpty() {
 		return EMPTY;
 	}

 	public static final FileFingerprint create(IPath path, IProgressMonitor monitor) throws CoreException {
 		return getEmpty().test(path, monitor).getNewFingerprint();
 	}

 	public FileFingerprint(long time, long size, long hash) {
 		super();
 		this.time = time;
 		this.size = size;
 		this.hash = hash;
 	}

 	public long getTime() {
 		return this.time;
 	}

 	public long getHash() {
 		return this.hash;
 	}

 	public long getSize() {
 		return this.size;
 	}

 	@Override
 	public int hashCode() {
 		final int prime = 31;
 		int result = 1;
 		result = prime * result + (int) (this.hash ^ (this.hash >>> 32));
 		result = prime * result + (int) (this.size ^ (this.size >>> 32));
 		result = prime * result + (int) (this.time ^ (this.time >>> 32));
 		return result;
 	}

 	@Override
 	public boolean equals(Object obj) {
 		if (this == obj)
 			return true;
 		if (obj == null)
 			return false;
 		if (getClass() != obj.getClass())
 			return false;
 		FileFingerprint other = (FileFingerprint) obj;
 		if (this.hash != other.hash)
 			return false;
 		if (this.size != other.size)
 			return false;
 		if (this.time != other.time)
 			return false;
 		return true;
 	}

 	public static class FingerprintTestResult {
 		private boolean matches;
 		private boolean needsNewFingerprint;
 		private FileFingerprint newFingerprint;

 		public FingerprintTestResult(boolean matches, boolean needsNewFingerprint, FileFingerprint newFingerprint) {
 			super();
 			this.matches = matches;
 			this.newFingerprint = newFingerprint;
 			this.needsNewFingerprint = needsNewFingerprint;
 		}

 		public boolean needsNewFingerprint() {
 			return this.needsNewFingerprint;
 		}

 		public boolean matches() {
 			return this.matches;
 		}

 		public FileFingerprint getNewFingerprint() {
 			return this.newFingerprint;
 		}

 		@Override
 		public String toString() {
 			return "FingerprintTestResult [matches=" + this.matches + ", needsNewFingerprint="  //$NON-NLS-1$//$NON-NLS-2$
 					+ this.needsNewFingerprint + ", newFingerprint=" + this.newFingerprint + "]";  //$NON-NLS-1$//$NON-NLS-2$
 		}
 	}

 	/**
 	 * Returns true iff the file existed at the time the fingerprint was computed.
 	 *
 	 * @return true iff the file existed at the time the fingerprint was computed.
 	 */
 	public boolean fileExists() {
 		return !equals(EMPTY);
 	}

 	/**
 	 * Compares the given File with the receiver. If the fingerprint matches (ie: the file
 	 */
 	public FingerprintTestResult test(IPath path, IProgressMonitor monitor) throws CoreException {
 		SubMonitor subMonitor = SubMonitor.convert(monitor, 100);
 		long currentTime = System.currentTimeMillis();
 		IFileStore store = EFS.getLocalFileSystem().getStore(path);
 		IFileInfo fileInfo = store.fetchInfo();

 		long lastModified = fileInfo.getLastModified();
 		if (Math.abs(currentTime - lastModified) < WORST_FILESYSTEM_TIMESTAMP_ACCURACY_MS) {
 			// If the file was modified so recently that it's within our ability to measure it, don't include
 			// the timestamp as part of the fingerprint. If another change were to happen to the file immediately
 			// afterward, we might not be able to detect it using the timestamp.
 			lastModified = UNKNOWN;
 		}
 		subMonitor.split(5);

 		long fileSize = fileInfo.getLength();
 		subMonitor.split(5);
 		if (lastModified != UNKNOWN && lastModified == this.time && fileSize == this.size) {
 			return new FingerprintTestResult(true, false, this);
 		}

 		long hashCode;
 		try {
 			hashCode = fileSize == 0 ? 0 : computeHashCode(path.toFile(), fileSize, subMonitor.split(90));
 		} catch (IOException e) {
 			throw new CoreException(Package.createStatus("An error occurred computing a hash code", e)); //$NON-NLS-1$
 		}
 		boolean matches = (hashCode == this.hash && fileSize == this.size);

 		FileFingerprint newFingerprint = new FileFingerprint(lastModified, fileSize, hashCode);
 		return new FingerprintTestResult(matches, !equals(newFingerprint), newFingerprint);
 	}

 	private long computeHashCode(File toTest, long fileSize, IProgressMonitor monitor) throws IOException {
 		final int BUFFER_SIZE = 2048;
 		char[] charBuffer = new char[BUFFER_SIZE];
 		byte[] byteBuffer = new byte[BUFFER_SIZE * 2];

 		SubMonitor subMonitor = SubMonitor.convert(monitor, (int) (fileSize / (BUFFER_SIZE * 2)));
 		StreamHasher hasher = new StreamHasher();
 		try {
 			InputStream inputStream = new FileInputStream(toTest);
 			try {
 				while (true) {
 					subMonitor.split(1);
 					int bytesRead = readUntilBufferFull(inputStream, byteBuffer);

 					if (bytesRead < byteBuffer.length) {
 						charBuffer = new char[(bytesRead + 1) / 2];
 						copyByteArrayToCharArray(charBuffer, byteBuffer, bytesRead);
 						hasher.addChunk(charBuffer);
 						break;
 					}

 					copyByteArrayToCharArray(charBuffer, byteBuffer, bytesRead);
 					hasher.addChunk(charBuffer);
 				}
 			} finally {
 				inputStream.close();
 			}

 		} catch (FileNotFoundException e) {
 			return 0;
 		}

 		return hasher.computeHash();
 	}

 	private void copyByteArrayToCharArray(char[] charBuffer, byte[] byteBuffer, int bytesToCopy) {
 		for (int ch = 0; ch < bytesToCopy / 2; ch++) {
 			char next = (char) (byteBuffer[ch * 2] + byteBuffer[ch * 2 + 1]);
 			charBuffer[ch] = next;
 		}

 		if (bytesToCopy % 2 != 0) {
 			charBuffer[bytesToCopy / 2] = (char) byteBuffer[bytesToCopy - 1];
 		}
 	}

 	int readUntilBufferFull(InputStream inputStream, byte[] buffer) throws IOException {
 		int bytesRead = 0;
 		while (bytesRead < buffer.length) {
 			int thisRead = inputStream.read(buffer, bytesRead, buffer.length - bytesRead);

 			if (thisRead == -1) {
 				return bytesRead;
 			}

 			bytesRead += thisRead;
 		}
 		return bytesRead;
 	}

 	private static String getTimeString(long timestamp) {
 		if (timestamp == UNKNOWN) {
 			return "UNKNOWN"; //$NON-NLS-1$
 		} else if (timestamp == NEVER_MODIFIED) {
 			return "NEVER_MODIFIED"; //$NON-NLS-1$
 		}
 		return Long.toString(timestamp);
 	}

 	@Override
 	public String toString() {
 		return "FileFingerprint [time=" + getTimeString(this.time) + ", size=" + this.size + ", hash=" + this.hash + "]";    //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$//$NON-NLS-4$
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2015, 2016 Google, Inc 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
	*
	* Contributors:
	* Stefan Xenos (Google) - Initial implementation
	*******************************************************************************/
	package org.aspectj.org.eclipse.jdt.internal.core.nd.java;

	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.io.InputStream;

	import org.eclipse.core.filesystem.EFS;
	import org.eclipse.core.filesystem.IFileInfo;
	import org.eclipse.core.filesystem.IFileStore;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.SubMonitor;
	import org.aspectj.org.eclipse.jdt.internal.core.nd.StreamHasher;

	public class FileFingerprint {
	/**
	* Sentinel value for {@link #time} indicating a nonexistent fingerprint. This is used for the timestamp of
	* nonexistent files and for the {@link #getEmpty()} singleton.
	*/
	public static final long NEVER_MODIFIED = 0;

	/**
	* Sentinel value for {@link #time} indicating that the timestamp was not recorded as part of the fingerprint.
	* This is normally used to indicate that the file's timestamp was so close to the current system time at the time
	* the fingerprint was computed that subsequent changes in the file might not be detected. In such cases, timestamps
	* are an unreliable method for determining if the file has changed and so are not included as part of the fingerprint.
	*/
	public static final long UNKNOWN = 1;

	/**
	* Worst-case accuracy of filesystem timestamps, among all supported platforms (this is currently 1s on linux, 2s on
	* FAT systems).
	*/
	private static final long WORST_FILESYSTEM_TIMESTAMP_ACCURACY_MS = 2000;

	private long time;
	private long hash;
	private long size;

	private static final FileFingerprint EMPTY = new FileFingerprint(NEVER_MODIFIED,0,0);

	public static final FileFingerprint getEmpty() {
	return EMPTY;
	}

	public static final FileFingerprint create(IPath path, IProgressMonitor monitor) throws CoreException {
	return getEmpty().test(path, monitor).getNewFingerprint();
	}

	public FileFingerprint(long time, long size, long hash) {
	super();
	this.time = time;
	this.size = size;
	this.hash = hash;
	}

	public long getTime() {
	return this.time;
	}

	public long getHash() {
	return this.hash;
	}

	public long getSize() {
	return this.size;
	}

	@Override
	public int hashCode() {
	final int prime = 31;
	int result = 1;
	result = prime * result + (int) (this.hash ^ (this.hash >>> 32));
	result = prime * result + (int) (this.size ^ (this.size >>> 32));
	result = prime * result + (int) (this.time ^ (this.time >>> 32));
	return result;
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj)
	return true;
	if (obj == null)
	return false;
	if (getClass() != obj.getClass())
	return false;
	FileFingerprint other = (FileFingerprint) obj;
	if (this.hash != other.hash)
	return false;
	if (this.size != other.size)
	return false;
	if (this.time != other.time)
	return false;
	return true;
	}

	public static class FingerprintTestResult {
	private boolean matches;
	private boolean needsNewFingerprint;
	private FileFingerprint newFingerprint;

	public FingerprintTestResult(boolean matches, boolean needsNewFingerprint, FileFingerprint newFingerprint) {
	super();
	this.matches = matches;
	this.newFingerprint = newFingerprint;
	this.needsNewFingerprint = needsNewFingerprint;
	}

	public boolean needsNewFingerprint() {
	return this.needsNewFingerprint;
	}

	public boolean matches() {
	return this.matches;
	}

	public FileFingerprint getNewFingerprint() {
	return this.newFingerprint;
	}

	@Override
	public String toString() {
	return "FingerprintTestResult [matches=" + this.matches + ", needsNewFingerprint=" //$NON-NLS-1$//$NON-NLS-2$
	+ this.needsNewFingerprint + ", newFingerprint=" + this.newFingerprint + "]"; //$NON-NLS-1$//$NON-NLS-2$
	}
	}

	/**
	* Returns true iff the file existed at the time the fingerprint was computed.
	*
	* @return true iff the file existed at the time the fingerprint was computed.
	*/
	public boolean fileExists() {
	return !equals(EMPTY);
	}

	/**
	* Compares the given File with the receiver. If the fingerprint matches (ie: the file
	*/
	public FingerprintTestResult test(IPath path, IProgressMonitor monitor) throws CoreException {
	SubMonitor subMonitor = SubMonitor.convert(monitor, 100);
	long currentTime = System.currentTimeMillis();
	IFileStore store = EFS.getLocalFileSystem().getStore(path);
	IFileInfo fileInfo = store.fetchInfo();

	long lastModified = fileInfo.getLastModified();
	if (Math.abs(currentTime - lastModified) < WORST_FILESYSTEM_TIMESTAMP_ACCURACY_MS) {
	// If the file was modified so recently that it's within our ability to measure it, don't include
	// the timestamp as part of the fingerprint. If another change were to happen to the file immediately
	// afterward, we might not be able to detect it using the timestamp.
	lastModified = UNKNOWN;
	}
	subMonitor.split(5);

	long fileSize = fileInfo.getLength();
	subMonitor.split(5);
	if (lastModified != UNKNOWN && lastModified == this.time && fileSize == this.size) {
	return new FingerprintTestResult(true, false, this);
	}

	long hashCode;
	try {
	hashCode = fileSize == 0 ? 0 : computeHashCode(path.toFile(), fileSize, subMonitor.split(90));
	} catch (IOException e) {
	throw new CoreException(Package.createStatus("An error occurred computing a hash code", e)); //$NON-NLS-1$
	}
	boolean matches = (hashCode == this.hash && fileSize == this.size);

	FileFingerprint newFingerprint = new FileFingerprint(lastModified, fileSize, hashCode);
	return new FingerprintTestResult(matches, !equals(newFingerprint), newFingerprint);
	}

	private long computeHashCode(File toTest, long fileSize, IProgressMonitor monitor) throws IOException {
	final int BUFFER_SIZE = 2048;
	char[] charBuffer = new char[BUFFER_SIZE];
	byte[] byteBuffer = new byte[BUFFER_SIZE * 2];

	SubMonitor subMonitor = SubMonitor.convert(monitor, (int) (fileSize / (BUFFER_SIZE * 2)));
	StreamHasher hasher = new StreamHasher();
	try {
	InputStream inputStream = new FileInputStream(toTest);
	try {
	while (true) {
	subMonitor.split(1);
	int bytesRead = readUntilBufferFull(inputStream, byteBuffer);

	if (bytesRead < byteBuffer.length) {
	charBuffer = new char[(bytesRead + 1) / 2];
	copyByteArrayToCharArray(charBuffer, byteBuffer, bytesRead);
	hasher.addChunk(charBuffer);
	break;
	}

	copyByteArrayToCharArray(charBuffer, byteBuffer, bytesRead);
	hasher.addChunk(charBuffer);
	}
	} finally {
	inputStream.close();
	}

	} catch (FileNotFoundException e) {
	return 0;
	}

	return hasher.computeHash();
	}

	private void copyByteArrayToCharArray(char[] charBuffer, byte[] byteBuffer, int bytesToCopy) {
	for (int ch = 0; ch < bytesToCopy / 2; ch++) {
	char next = (char) (byteBuffer[ch * 2] + byteBuffer[ch * 2 + 1]);
	charBuffer[ch] = next;
	}

	if (bytesToCopy % 2 != 0) {
	charBuffer[bytesToCopy / 2] = (char) byteBuffer[bytesToCopy - 1];
	}
	}

	int readUntilBufferFull(InputStream inputStream, byte[] buffer) throws IOException {
	int bytesRead = 0;
	while (bytesRead < buffer.length) {
	int thisRead = inputStream.read(buffer, bytesRead, buffer.length - bytesRead);

	if (thisRead == -1) {
	return bytesRead;
	}

	bytesRead += thisRead;
	}
	return bytesRead;
	}

	private static String getTimeString(long timestamp) {
	if (timestamp == UNKNOWN) {
	return "UNKNOWN"; //$NON-NLS-1$
	} else if (timestamp == NEVER_MODIFIED) {
	return "NEVER_MODIFIED"; //$NON-NLS-1$
	}
	return Long.toString(timestamp);
	}

	@Override
	public String toString() {
	return "FileFingerprint [time=" + getTimeString(this.time) + ", size=" + this.size + ", hash=" + this.hash + "]"; //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$//$NON-NLS-4$
	}
	}