/*******************************************************************************
* Copyright (c) 2000, 2016 QNX Software Systems 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:
* QNX Software Systems - Initial API and implementation
* Anton Leherbauer (Wind River Systems)
* Sergey Prigogin (Google)
*******************************************************************************/
package org.eclipse.cdt.internal.ui.text;
import java.util.ArrayList;
import java.util.List;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.text.contentassist.IContextInformationPresenter;
import org.eclipse.jface.text.contentassist.IContextInformationValidator;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyleRange;
/**
* This class provides the function parameter parsing for the C/C++ Editor hover.
* It is based heavily on the Java class JavaParameterListValidator.
*
* @author thomasf
*/
public class CParameterListValidator implements IContextInformationValidator, IContextInformationPresenter {
private int fPosition;
private ITextViewer fViewer;
private IContextInformation fInformation;
private int fCurrentParameter;
public CParameterListValidator() {
}
/**
* @see IContextInformationValidator#install(IContextInformation, ITextViewer, int)
* @see IContextInformationPresenter#install(IContextInformation, ITextViewer, int)
*/
@Override
public void install(IContextInformation info, ITextViewer viewer, int documentPosition) {
fPosition= documentPosition;
fViewer= viewer;
fInformation= info;
fCurrentParameter= -1;
}
private int getCommentEnd(IDocument d, int pos, int end) throws BadLocationException {
while (pos < end) {
char curr= d.getChar(pos);
pos++;
if (curr == '*') {
if (pos < end && d.getChar(pos) == '/') {
return pos + 1;
}
}
}
return end;
}
private int getStringEnd(IDocument d, int pos, int end, char ch) throws BadLocationException {
while (pos < end) {
char curr= d.getChar(pos);
pos++;
if (curr == '\\') {
// Ignore escaped characters.
pos++;
} else if (curr == ch) {
return pos;
}
}
return end;
}
private int getCharCount(IDocument document, int start, int end, char increment, char decrement,
boolean considerNesting) throws BadLocationException {
Assert.isTrue((increment != 0 || decrement != 0) && increment != decrement);
int parenNestingLevel = 0;
int braceNestingLevel = 0;
int charCount = 0;
while (start < end) {
char curr = document.getChar(start++);
switch (curr) {
case '/':
if (start < end) {
char next= document.getChar(start);
if (next == '*') {
// A comment starts, advance to the comment end.
start= getCommentEnd(document, start + 1, end);
} else if (next == '/') {
// '//'-comment: nothing to do anymore on this line
start= end;
}
}
break;
case '*':
if (start < end) {
char next= document.getChar(start);
if (next == '/') {
// We have been in a comment: forget what we read before.
charCount= 0;
++ start;
}
}
break;
case '"':
case '\'':
start= getStringEnd(document, start, end, curr);
break;
default:
if (considerNesting) {
if ('(' == curr) {
++parenNestingLevel;
} else if (')' == curr) {
--parenNestingLevel;
}
if (parenNestingLevel != 0)
break;
if ('{' == curr) {
++braceNestingLevel;
} else if ('}' == curr) {
--braceNestingLevel;
}
if (braceNestingLevel != 0)
break;
}
if (increment != 0) {
if (curr == increment)
++charCount;
}
if (decrement != 0) {
if (curr == decrement)
--charCount;
}
}
}
return charCount;
}
/**
* @see IContextInformationValidator#isContextInformationValid(int)
*/
@Override
public boolean isContextInformationValid(int position) {
try {
if (position < fPosition)
return false;
IDocument document= fViewer.getDocument();
return getCharCount(document, fPosition, position, '(', ')', false) >= 0;
} catch (BadLocationException x) {
return false;
}
}
@Override
public boolean updatePresentation(int position, TextPresentation presentation) {
int currentParameter= -1;
try {
currentParameter= getCharCount(fViewer.getDocument(), fPosition, position, ',', (char) 0, true);
} catch (BadLocationException x) {
return false;
}
if (fCurrentParameter != -1) {
if (currentParameter == fCurrentParameter)
return false;
}
presentation.clear();
fCurrentParameter= currentParameter;
// Don't presume what has been done to the string, rather use as is.
String s= fInformation.getInformationDisplayString();
int[] commas= computeCommaPositions(s);
if (commas.length - 2 < fCurrentParameter) {
presentation.addStyleRange(new StyleRange(0, s.length(), null, null, SWT.NORMAL));
return true;
}
int start= commas[fCurrentParameter] + 1;
int end= commas[fCurrentParameter + 1];
if (start > 0)
presentation.addStyleRange(new StyleRange(0, start, null, null, SWT.NORMAL));
if (end > start)
presentation.addStyleRange(new StyleRange(start, end - start, null, null, SWT.BOLD));
if (end < s.length())
presentation.addStyleRange(new StyleRange(end, s.length() - end, null, null, SWT.NORMAL));
return true;
}
private int[] computeCommaPositions(String code) {
final int length= code.length();
int pos= 0;
List<Integer> positions= new ArrayList<>();
positions.add(Integer.valueOf(-1));
while (pos < length && pos != -1) {
char ch= code.charAt(pos);
switch (ch) {
case ',':
positions.add(Integer.valueOf(pos));
break;
case '(':
pos= indexOfClosingPeer(code, '(', ')', pos);
break;
case '<':
pos= indexOfClosingPeer(code, '<', '>', pos);
break;
case '[':
pos= indexOfClosingPeer(code, '[', ']', pos);
break;
case '{':
pos= indexOfClosingPeer(code, '{', '}', pos);
break;
default:
break;
}
if (pos != -1)
pos++;
}
positions.add(Integer.valueOf(length));
int[] fields= new int[positions.size()];
for (int i= 0; i < fields.length; i++)
fields[i]= positions.get(i).intValue();
return fields;
}
private int indexOfClosingPeer(String code, char left, char right, int pos) {
int level= 0;
final int length= code.length();
while (pos < length) {
char ch= code.charAt(pos);
if (ch == left) {
++level;
} else if (ch == right) {
if (--level == 0) {
return pos;
}
}
++pos;
}
return -1;
}
}