| /******************************************************************************* |
| * Copyright (c) 2000, 2018 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.compare.internal; |
| |
| import org.eclipse.compare.ICompareFilter; |
| import org.eclipse.compare.contentmergeviewer.ITokenComparator; |
| import org.eclipse.compare.rangedifferencer.IRangeComparator; |
| import org.eclipse.core.internal.expressions.util.LRUCache; |
| import org.eclipse.jface.text.BadLocationException; |
| import org.eclipse.jface.text.IDocument; |
| import org.eclipse.jface.text.IRegion; |
| |
| /** |
| * Implements the <code>IRangeComparator</code> interface for lines in a document. |
| * A <code>DocLineComparator</code> is used as the input for the <code>RangeDifferencer</code> |
| * engine to perform a line oriented compare on documents. |
| * <p> |
| * A <code>DocLineComparator</code> doesn't know anything about line separators because |
| * its notion of lines is solely defined in the underlying <code>IDocument</code>. |
| */ |
| public class DocLineComparator implements ITokenComparator { |
| |
| private IDocument fDocument; |
| private int fLineOffset; |
| private int fLineCount; |
| private int fLength; |
| private boolean fIgnoreWhiteSpace; |
| private ICompareFilter[] fCompareFilters; |
| private char fContributor; |
| private LRUCache fCompareFilterCache; |
| |
| /** |
| * Creates a <code>DocLineComparator</code> for the given document range. |
| * ignoreWhiteSpace controls whether comparing lines (in method |
| * <code>rangesEqual<code>) should ignore whitespace. |
| * |
| * @param document the document from which the lines are taken |
| * @param region if non-<code>null</code> only lines within this range are taken |
| * @param ignoreWhiteSpace if <code>true</code> white space is ignored when comparing lines |
| */ |
| public DocLineComparator(IDocument document, IRegion region, |
| boolean ignoreWhiteSpace) { |
| this(document, region, ignoreWhiteSpace, null, '?'); |
| } |
| |
| /** |
| * Creates a <code>DocLineComparator</code> for the given document range. |
| * ignoreWhiteSpace controls whether comparing lines (in method |
| * <code>rangesEqual<code>) should ignore whitespace. Compare filters may be used |
| * to affect the detection of line differences. |
| * |
| * @param document |
| * the document from which the lines are taken |
| * @param region |
| * if non-<code>null</code> only lines within this range are |
| * taken |
| * @param ignoreWhiteSpace |
| * if <code>true</code> white space is ignored when comparing |
| * lines |
| * @param compareFilters |
| * the active compare filters for the compare |
| * @param contributor |
| * contributor of document |
| */ |
| public DocLineComparator(IDocument document, IRegion region, |
| boolean ignoreWhiteSpace, ICompareFilter[] compareFilters, |
| char contributor) { |
| fDocument = document; |
| fIgnoreWhiteSpace = ignoreWhiteSpace; |
| fCompareFilters = compareFilters; |
| fContributor = contributor; |
| |
| boolean cacheFilteredLines = false; |
| if (compareFilters != null && compareFilters.length > 0) { |
| cacheFilteredLines = true; |
| for (int i = 0; i < compareFilters.length; i++) { |
| if (!compareFilters[i].canCacheFilteredRegions()) { |
| cacheFilteredLines = false; |
| break; |
| } |
| } |
| } |
| fCompareFilterCache = (cacheFilteredLines) ? new LRUCache(1024) : null; |
| |
| fLineOffset = 0; |
| if (region != null) { |
| fLength = region.getLength(); |
| int start = region.getOffset(); |
| try { |
| fLineOffset = fDocument.getLineOfOffset(start); |
| } catch (BadLocationException ex) { |
| // silently ignored |
| } |
| |
| if (fLength == 0) { |
| // optimization, empty documents have one line |
| fLineCount = 1; |
| } else { |
| int endLine = fDocument.getNumberOfLines(); |
| try { |
| endLine = fDocument.getLineOfOffset(start + fLength); |
| } catch (BadLocationException ex) { |
| // silently ignored |
| } |
| fLineCount = endLine - fLineOffset + 1; |
| } |
| } else { |
| fLength = document.getLength(); |
| fLineCount = fDocument.getNumberOfLines(); |
| } |
| } |
| |
| /** |
| * Returns the number of lines in the document. |
| * |
| * @return number of lines |
| */ |
| @Override |
| public int getRangeCount() { |
| return fLineCount; |
| } |
| |
| /* (non Javadoc) |
| * see ITokenComparator.getTokenStart |
| */ |
| @Override |
| public int getTokenStart(int line) { |
| try { |
| IRegion r= fDocument.getLineInformation(fLineOffset + line); |
| return r.getOffset(); |
| } catch (BadLocationException ex) { |
| return fDocument.getLength(); |
| } |
| } |
| |
| /* (non Javadoc) |
| * Returns the length of the given line. |
| * see ITokenComparator.getTokenLength |
| */ |
| @Override |
| public int getTokenLength(int line) { |
| return getTokenStart(line+1) - getTokenStart(line); |
| } |
| |
| /** |
| * Returns <code>true</code> if a line given by the first index |
| * matches a line specified by the other <code>IRangeComparator</code> and index. |
| * |
| * @param thisIndex the number of the line within this range comparator |
| * @param otherComparator the range comparator to compare this with |
| * @param otherIndex the number of the line within the other comparator |
| * @return <code>true</code> if the lines are equal |
| */ |
| @Override |
| public boolean rangesEqual(int thisIndex, IRangeComparator otherComparator, int otherIndex) { |
| |
| if (otherComparator != null && otherComparator.getClass() == getClass()) { |
| DocLineComparator other= (DocLineComparator) otherComparator; |
| |
| if (fIgnoreWhiteSpace) { |
| String[] linesToCompare = extract(thisIndex, otherIndex, other, false); |
| return compare(linesToCompare[0], linesToCompare[1]); |
| } |
| |
| int tlen= getTokenLength(thisIndex); |
| int olen= other.getTokenLength(otherIndex); |
| if (fCompareFilters != null && fCompareFilters.length > 0) { |
| String[] linesToCompare = extract(thisIndex, otherIndex, other, true); |
| return linesToCompare[0].equals(linesToCompare[1]); |
| } else if (tlen == olen) { |
| String[] linesToCompare = extract(thisIndex, otherIndex, other, false); |
| return linesToCompare[0].equals(linesToCompare[1]); |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Aborts the comparison if the number of tokens is too large. |
| * |
| * @param length a number on which to base the decision whether to return |
| * <code>true</code> or <code>false</code> |
| * @param maxLength another number on which to base the decision whether to return |
| * <code>true</code> or <code>false</code> |
| * @param other the other <code>IRangeComparator</code> to compare with |
| * @return <code>true</code> to avoid a too lengthy range comparison |
| */ |
| @Override |
| public boolean skipRangeComparison(int length, int maxLength, IRangeComparator other) { |
| return false; |
| } |
| |
| //---- private methods |
| |
| private String[] extract(int thisIndex, int otherIndex, |
| DocLineComparator other, boolean includeSeparator) { |
| |
| String[] extracts = new String[2]; |
| if (fCompareFilters != null && fCompareFilters.length > 0) { |
| if (fCompareFilterCache != null |
| && other.fCompareFilterCache != null) { |
| extracts[0] = (String) fCompareFilterCache.get(Integer.valueOf( |
| thisIndex)); |
| if (extracts[0] == null) { |
| extracts[0] = Utilities.applyCompareFilters( |
| extract(thisIndex, includeSeparator), fContributor, |
| other.extract(otherIndex, includeSeparator), other.fContributor, |
| fCompareFilters); |
| fCompareFilterCache |
| .put(Integer.valueOf(thisIndex), extracts[0]); |
| } |
| |
| extracts[1] = (String) other.fCompareFilterCache |
| .get(Integer.valueOf(otherIndex)); |
| if (extracts[1] == null) { |
| extracts[1] = Utilities.applyCompareFilters( |
| other.extract(otherIndex, includeSeparator), other.fContributor, |
| extract(thisIndex, includeSeparator), fContributor, fCompareFilters); |
| other.fCompareFilterCache.put(Integer.valueOf(otherIndex), |
| extracts[1]); |
| } |
| } else { |
| String thisLine = extract(thisIndex, includeSeparator); |
| String otherLine = other.extract(otherIndex, includeSeparator); |
| extracts = new String[] { |
| Utilities.applyCompareFilters(thisLine, fContributor, |
| otherLine, other.fContributor, fCompareFilters), |
| Utilities.applyCompareFilters(otherLine, |
| other.fContributor, thisLine, fContributor, |
| fCompareFilters) }; |
| } |
| } else { |
| extracts = new String[] { extract(thisIndex, includeSeparator), |
| other.extract(otherIndex, includeSeparator) }; |
| } |
| return extracts; |
| } |
| |
| /** |
| * Extract a single line from the underlying document. |
| * |
| * @param line the number of the line to extract |
| * @param whether to include the line separator |
| * @return the contents of the line as a String |
| */ |
| private String extract(int line, boolean includeSeparator) { |
| if (line < fLineCount) { |
| try { |
| if (includeSeparator) |
| return fDocument.get(fDocument.getLineOffset(line), |
| fDocument.getLineLength(line)); |
| |
| IRegion r = fDocument.getLineInformation(fLineOffset + line); |
| return fDocument.get(r.getOffset(), r.getLength()); |
| |
| } catch (BadLocationException e) { |
| // silently ignored |
| } |
| } |
| return ""; //$NON-NLS-1$ |
| } |
| |
| private boolean compare(String s1, String s2) { |
| int l1= s1.length(); |
| int l2= s2.length(); |
| int c1= 0, c2= 0; |
| int i1= 0, i2= 0; |
| |
| while (c1 != -1) { |
| |
| c1= -1; |
| while (i1 < l1) { |
| char c= s1.charAt(i1++); |
| if (! Character.isWhitespace(c)) { |
| c1= c; |
| break; |
| } |
| } |
| |
| c2= -1; |
| while (i2 < l2) { |
| char c= s2.charAt(i2++); |
| if (! Character.isWhitespace(c)) { |
| c2= c; |
| break; |
| } |
| } |
| |
| if (c1 != c2) |
| return false; |
| } |
| return true; |
| } |
| } |
| |