/*******************************************************************************
* Copyright (c) 2004, 2007 IBM Corporation 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
/*
* Created on Sep 2, 2003
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package org.eclipse.wst.jsdt.web.ui.internal.text;
import java.io.IOException;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.wst.jsdt.web.ui.internal.derived.SingleCharReader;
/**
*
* Provisional API: This class/interface is part of an interim API that is still under development and expected to
* change significantly before reaching stability. It is being made available at this early stage to solicit feedback
* from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken
* (repeatedly) as the API evolves.
*/
class JsCodeReader extends SingleCharReader {
/** The EOF character */
public static final int EOF = -1;
private int fCachedLineNumber = -1;
private int fCachedLineOffset = -1;
private IDocument fDocument;
private int fEnd = -1;
private boolean fForward = false;
private int fOffset;
private boolean fSkipComments = false;
private boolean fSkipStrings = false;
public JsCodeReader() {}
/*
* @see Reader#close()
*/
public void close() throws IOException {
fDocument = null;
}
public void configureBackwardReader(IDocument document, int offset, boolean skipComments, boolean skipStrings) throws IOException {
fDocument = document;
fOffset = offset;
fSkipComments = skipComments;
fSkipStrings = skipStrings;
fForward = false;
try {
fCachedLineNumber = fDocument.getLineOfOffset(fOffset);
} catch (BadLocationException x) {
throw new IOException(x.getMessage());
}
}
public void configureForwardReader(IDocument document, int offset, int length, boolean skipComments, boolean skipStrings) throws IOException {
fDocument = document;
fOffset = offset;
fSkipComments = skipComments;
fSkipStrings = skipStrings;
fForward = true;
fEnd = Math.min(fDocument.getLength(), fOffset + length);
}
/**
* Returns the offset of the last read character. Should only be called
* after read has been called.
*/
public int getOffset() {
return fForward ? fOffset - 1 : fOffset;
}
private void gotoCommentEnd() throws BadLocationException {
while (fOffset < fEnd) {
char current = fDocument.getChar(fOffset++);
if (current == '*') {
if (fOffset < fEnd && fDocument.getChar(fOffset) == '/') {
++fOffset;
return;
}
}
}
}
private void gotoCommentStart() throws BadLocationException {
while (0 < fOffset) {
char current = fDocument.getChar(fOffset--);
if (current == '*' && 0 <= fOffset && fDocument.getChar(fOffset) == '/') {
return;
}
}
}
private void gotoLineEnd() throws BadLocationException {
int line = fDocument.getLineOfOffset(fOffset);
fOffset = fDocument.getLineOffset(line + 1);
}
private void gotoStringEnd(char delimiter) throws BadLocationException {
while (fOffset < fEnd) {
char current = fDocument.getChar(fOffset++);
if (current == '\\') {
// ignore escaped characters
++fOffset;
} else if (current == delimiter) {
return;
}
}
}
private void gotoStringStart(char delimiter) throws BadLocationException {
while (0 < fOffset) {
char current = fDocument.getChar(fOffset);
if (current == delimiter) {
if (!(0 <= fOffset && fDocument.getChar(fOffset - 1) == '\\')) {
return;
}
}
--fOffset;
}
}
private void handleSingleLineComment() throws BadLocationException {
int line = fDocument.getLineOfOffset(fOffset);
if (line < fCachedLineNumber) {
fCachedLineNumber = line;
fCachedLineOffset = fDocument.getLineOffset(line);
int offset = fOffset;
while (fCachedLineOffset < offset) {
char current = fDocument.getChar(offset--);
if (current == '/' && fCachedLineOffset <= offset && fDocument.getChar(offset) == '/') {
fOffset = offset;
return;
}
}
}
}
/*
* @see SingleCharReader#read()
*/
public int read() throws IOException {
try {
return fForward ? readForwards() : readBackwards();
} catch (BadLocationException x) {
throw new IOException(x.getMessage());
}
}
private int readBackwards() throws BadLocationException {
while (0 < fOffset) {
--fOffset;
handleSingleLineComment();
char current = fDocument.getChar(fOffset);
switch (current) {
case '/':
if (fSkipComments && fOffset > 1) {
char next = fDocument.getChar(fOffset - 1);
if (next == '*') {
// a comment ends, advance to the comment start
fOffset -= 2;
gotoCommentStart();
continue;
}
}
return current;
case '"':
case '\'':
if (fSkipStrings) {
--fOffset;
gotoStringStart(current);
continue;
}
return current;
}
return current;
}
return JsCodeReader.EOF;
}
private int readForwards() throws BadLocationException {
while (fOffset < fEnd) {
char current = fDocument.getChar(fOffset++);
switch (current) {
case '/':
if (fSkipComments && fOffset < fEnd) {
char next = fDocument.getChar(fOffset);
if (next == '*') {
// a comment starts, advance to the comment end
++fOffset;
gotoCommentEnd();
continue;
} else if (next == '/') {
// '//'-comment starts, advance to the line end
gotoLineEnd();
continue;
}
}
return current;
case '"':
case '\'':
if (fSkipStrings) {
gotoStringEnd(current);
continue;
}
return current;
}
return current;
}
return JsCodeReader.EOF;
}
}