/*******************************************************************************
* Copyright (c) 2000, 2011 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
* QNX Software System
* Anton Leherbauer (Wind River Systems)
*******************************************************************************/
package org.eclipse.cdt.internal.ui.text;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.TextUtilities;
import org.eclipse.jface.text.source.DefaultCharacterPairMatcher;
import org.eclipse.jface.text.source.ICharacterPairMatcher;
import org.eclipse.cdt.core.dom.ILinkage;
import org.eclipse.cdt.core.model.ILanguage;
import org.eclipse.cdt.ui.text.ICPartitions;
/**
* Helper class to match pairs of characters.
*/
public class CPairMatcher extends DefaultCharacterPairMatcher {
private static final int ANGLE_BRACKETS_SEARCH_BOUND = 200;
private boolean fMatchAngularBrackets = true;
private int fAnchor = -1;
public CPairMatcher(char[] pairs) {
super(pairs, ICPartitions.C_PARTITIONING);
}
/* @see ICharacterPairMatcher#match(IDocument, int) */
@Override
public IRegion match(IDocument document, int offset) {
try {
return performMatch(document, offset);
} catch (BadLocationException ble) {
return null;
}
}
/*
* @see org.eclipse.jface.text.source.DefaultCharacterPairMatcher#getAnchor()
*/
@Override
public int getAnchor() {
if (fAnchor < 0) {
return super.getAnchor();
}
return fAnchor;
}
/*
* Performs the actual work of matching for #match(IDocument, int).
*/
private IRegion performMatch(IDocument document, int offset) throws BadLocationException {
if (offset < 0 || document == null)
return null;
final char prevChar = document.getChar(Math.max(offset - 1, 0));
if ((prevChar == '<' || prevChar == '>') && !fMatchAngularBrackets)
return null;
final IRegion region;
if (prevChar == '<') {
region = findClosingAngleBracket(document, offset - 1);
fAnchor = ICharacterPairMatcher.LEFT;
} else if (prevChar == '>') {
region = findOpeningAngleBracket(document, offset - 1);
fAnchor = ICharacterPairMatcher.RIGHT;
} else {
region = super.match(document, offset);
fAnchor = -1;
}
if (region != null) {
if (prevChar == '>') {
final int peer = region.getOffset();
if (isLessThanOperator(document, peer))
return null;
} else if (prevChar == '<') {
final int peer = region.getOffset() + region.getLength() - 1;
if (isGreaterThanOperator(document, peer))
return null;
}
}
return region;
}
/**
* Returns the region enclosing the matching angle brackets.
*
* @param document a document
* @param offset an offset within the document pointing after the closing angle bracket
* @return the matching region or {@link NullPointerException} if no match could be found
* @throws BadLocationException
*/
private IRegion findOpeningAngleBracket(IDocument document, int offset) throws BadLocationException {
if (offset < 0)
return null;
final String contentType = TextUtilities.getContentType(document, ICPartitions.C_PARTITIONING, offset, false);
CHeuristicScanner scanner = new CHeuristicScanner(document, ICPartitions.C_PARTITIONING, contentType);
if (isTemplateParameterCloseBracket(offset, document, scanner)) {
int pos = scanner.findOpeningPeer(offset - 1, Math.max(0, offset - ANGLE_BRACKETS_SEARCH_BOUND), '<', '>');
if (pos != CHeuristicScanner.NOT_FOUND) {
return new Region(pos, offset - pos + 1);
}
}
return null;
}
/**
* Returns the region enclosing the matching angle brackets.
*
* @param document a document
* @param offset an offset within the document pointing after the opening angle bracket
* @return the matching region or {@link NullPointerException} if no match could be found
* @throws BadLocationException
*/
private IRegion findClosingAngleBracket(IDocument document, int offset) throws BadLocationException {
if (offset < 0)
return null;
final String contentType = TextUtilities.getContentType(document, ICPartitions.C_PARTITIONING, offset, false);
CHeuristicScanner scanner = new CHeuristicScanner(document, ICPartitions.C_PARTITIONING, contentType);
if (isTemplateParameterOpenBracket(offset, document, scanner)) {
int pos = scanner.findClosingPeer(offset + 1,
Math.min(document.getLength(), offset + ANGLE_BRACKETS_SEARCH_BOUND), '<', '>');
if (pos != CHeuristicScanner.NOT_FOUND) {
return new Region(offset, pos - offset + 1);
}
}
return null;
}
/**
* Returns true if the character at the specified offset is a
* less-than sign, rather than an template parameter list open
* angle bracket.
*
* @param document a document
* @param offset an offset within the document
* @return true if the character at the specified offset is not
* a template parameter start bracket
* @throws BadLocationException
*/
private boolean isLessThanOperator(IDocument document, int offset) throws BadLocationException {
if (offset < 0)
return false;
final String contentType = TextUtilities.getContentType(document, ICPartitions.C_PARTITIONING, offset, false);
CHeuristicScanner scanner = new CHeuristicScanner(document, ICPartitions.C_PARTITIONING, contentType);
return !isTemplateParameterOpenBracket(offset, document, scanner);
}
/**
* Returns true if the character at the specified offset is a
* greater-than sign, rather than an template parameter list close
* angle bracket.
*
* @param document a document
* @param offset an offset within the document
* @return true if the character at the specified offset is not
* a template parameter end bracket
* @throws BadLocationException
*/
private boolean isGreaterThanOperator(IDocument document, int offset) throws BadLocationException {
if (offset < 0)
return false;
final String contentType = TextUtilities.getContentType(document, ICPartitions.C_PARTITIONING, offset, false);
CHeuristicScanner scanner = new CHeuristicScanner(document, ICPartitions.C_PARTITIONING, contentType);
return !isTemplateParameterCloseBracket(offset, document, scanner);
}
/**
* Checks if the angular bracket at <code>offset</code> is a template
* parameter bracket.
*
* @param offset the offset of the opening bracket
* @param document the document
* @param scanner a heuristic scanner on <code>document</code>
* @return <code>true</code> if the bracket is part of a template parameter,
* <code>false</code> otherwise
*/
private boolean isTemplateParameterOpenBracket(int offset, IDocument document, CHeuristicScanner scanner) {
int nextToken = scanner.nextToken(offset + 1,
Math.min(document.getLength(), offset + ANGLE_BRACKETS_SEARCH_BOUND));
if (nextToken == Symbols.TokenSHIFTLEFT || nextToken == Symbols.TokenLESSTHAN)
return false;
int prevToken = scanner.previousToken(offset - 1, Math.max(0, offset - ANGLE_BRACKETS_SEARCH_BOUND));
if (prevToken == Symbols.TokenIDENT || prevToken == Symbols.TokenTEMPLATE) {
return true;
}
return false;
}
/**
* Checks if the angular bracket at <code>offset</code> is a template
* parameter bracket.
*
* @param offset the offset of the closing bracket
* @param document the document
* @param scanner a heuristic scanner on <code>document</code>
* @return <code>true</code> if the bracket is part of a template parameter,
* <code>false</code> otherwise
*/
private boolean isTemplateParameterCloseBracket(int offset, IDocument document, CHeuristicScanner scanner) {
if (offset >= document.getLength() - 1)
return true;
int thisToken = scanner.previousToken(offset, Math.max(0, offset - ANGLE_BRACKETS_SEARCH_BOUND));
if (thisToken == Symbols.TokenSHIFTRIGHT)
return true;
if (thisToken != Symbols.TokenGREATERTHAN)
return false;
int prevToken = scanner.previousToken(scanner.getPosition(), Math.max(0, offset - ANGLE_BRACKETS_SEARCH_BOUND));
if (prevToken == Symbols.TokenGREATERTHAN)
return true;
int nextToken = scanner.nextToken(offset + 1,
Math.min(document.getLength(), offset + ANGLE_BRACKETS_SEARCH_BOUND));
switch (nextToken) {
case Symbols.TokenGREATERTHAN:
case Symbols.TokenCOMMA:
case Symbols.TokenSEMICOLON:
case Symbols.TokenCLASS:
case Symbols.TokenSTRUCT:
case Symbols.TokenUNION:
return true;
}
return false;
}
/**
* Configure this bracket matcher for the given language.
* @param language
*/
public void configure(ILanguage language) {
fMatchAngularBrackets = language != null && language.getLinkageID() == ILinkage.CPP_LINKAGE_ID;
}
}
