/*
* Copyright (C) 2007-2010 Júlio Vilmar Gesser.
* Copyright (C) 2011, 2013-2015 The JavaParser Team.
*
* This file is part of JavaParser.
*
* JavaParser can be used either under the terms of
* a) the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* b) the terms of the Apache License
*
* You should have received a copy of both licenses in LICENCE.LGPL and
* LICENCE.APACHE. Please refer to those files for details.
*
* JavaParser is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*/
package com.github.javaparser.ast.comments;
import java.io.*;
import java.nio.charset.Charset;
import java.util.*;
/**
* This parser cares exclusively about comments.
*/
public class CommentsParser {
private enum State {
CODE,
IN_LINE_COMMENT,
IN_BLOCK_COMMENT,
IN_STRING,
IN_CHAR
}
private static final int COLUMNS_PER_TAB = 4;
public CommentsCollection parse(final String source) throws IOException, UnsupportedEncodingException {
InputStream in = new ByteArrayInputStream(source.getBytes(Charset.defaultCharset()));
return parse(in, Charset.defaultCharset().name());
}
/**
* Track the internal state of the parser, remembering the last characters observed.
*/
class ParserState {
private Deque prevTwoChars = new LinkedList<Character>();
/**
* Is the last character the one expected?
*/
boolean isLastChar(char expectedChar) {
return prevTwoChars.size() >= 1 && prevTwoChars.peekLast().equals(expectedChar);
}
/**
* Is the character before the last one the same as expectedChar?
*/
public boolean isSecondToLastChar(char expectedChar) {
return prevTwoChars.size() >= 1 && prevTwoChars.peekFirst().equals(expectedChar);
}
/**
* Record a new character. It will be the last one. The character that was the last one will
* become the second to last one.
*/
public void update(char c) {
if (prevTwoChars.size() == 2) {
prevTwoChars.remove();
}
prevTwoChars.add(c);
}
/**
* Remove all the characters observed.
*/
public void reset() {
while (!prevTwoChars.isEmpty()) {
prevTwoChars.removeFirst();
}
}
}
public CommentsCollection parse(final InputStream in, final String charsetName) throws IOException, UnsupportedEncodingException {
boolean lastWasASlashR = false;
BufferedReader br = new BufferedReader(new InputStreamReader(in, charsetName));
CommentsCollection comments = new CommentsCollection();
int r;
ParserState parserState = new ParserState();
State state = State.CODE;
LineComment currentLineComment = null;
BlockComment currentBlockComment = null;
StringBuffer currentContent = null;
int currLine = 1;
int currCol = 1;
while ((r=br.read()) != -1){
char c = (char)r;
if (c=='\r'){
lastWasASlashR = true;
} else if (c=='\n'&&lastWasASlashR){
lastWasASlashR=false;
continue;
} else {
lastWasASlashR=false;
}
switch (state) {
case CODE:
if (parserState.isLastChar('/') && c == '/') {
currentLineComment = new LineComment();
currentLineComment.setBeginLine(currLine);
currentLineComment.setBeginColumn(currCol - 1);
state = State.IN_LINE_COMMENT;
currentContent = new StringBuffer();
} else if (parserState.isLastChar('/') && c == '*') {
currentBlockComment = new BlockComment();
currentBlockComment.setBeginLine(currLine);
currentBlockComment.setBeginColumn(currCol - 1);
state = State.IN_BLOCK_COMMENT;
currentContent = new StringBuffer();
} else if (c == '"') {
state = State.IN_STRING;
} else if (c == '\'') {
state = State.IN_CHAR;
} else {
// nothing to do
}
break;
case IN_LINE_COMMENT:
if (c=='\n' || c=='\r'){
currentLineComment.setContent(currentContent.toString());
currentLineComment.setEndLine(currLine);
currentLineComment.setEndColumn(currCol);
comments.addComment(currentLineComment);
state = State.CODE;
} else {
currentContent.append(c);
}
break;
case IN_BLOCK_COMMENT:
// '/*/' is not a valid block comment: it starts the block comment but it does not close it
// However this sequence can be contained inside a comment and in that case it close the comment
// For example:
// /* blah blah /*/
// At the previous line we had a valid block comment
if (parserState.isLastChar('*') && c=='/' && (!parserState.isSecondToLastChar('/') || currentContent.length() > 0)){
// delete last character
String content = currentContent.deleteCharAt(currentContent.toString().length()-1).toString();
if (content.startsWith("*")){
JavadocComment javadocComment = new JavadocComment();
javadocComment.setContent(content.substring(1));
javadocComment.setBeginLine(currentBlockComment.getBeginLine());
javadocComment.setBeginColumn(currentBlockComment.getBeginColumn());
javadocComment.setEndLine(currLine);
javadocComment.setEndColumn(currCol+1);
comments.addComment(javadocComment);
} else {
currentBlockComment.setContent(content);
currentBlockComment.setEndLine(currLine);
currentBlockComment.setEndColumn(currCol+1);
comments.addComment(currentBlockComment);
}
state = State.CODE;
} else {
currentContent.append(c=='\r'?'\n':c);
}
break;
case IN_STRING:
if (!parserState.isLastChar('\\') && c == '"') {
state = State.CODE;
}
break;
case IN_CHAR:
if (!parserState.isLastChar('\\') && c == '\'') {
state = State.CODE;
}
break;
default:
throw new RuntimeException("Unexpected");
}
switch (c){
case '\n':
case '\r':
currLine+=1;
currCol = 1;
break;
case '\t':
currCol+=COLUMNS_PER_TAB;
break;
default:
currCol+=1;
}
// ok we have two slashes in a row inside a string
// we want to replace them with... anything else, to not confuse
// the parser
if (state==State.IN_STRING && parserState.isLastChar('\\') && c == '\\') {
parserState.reset();
} else {
parserState.update(c);
}
}
if (state==State.IN_LINE_COMMENT){
currentLineComment.setContent(currentContent.toString());
currentLineComment.setEndLine(currLine);
currentLineComment.setEndColumn(currCol);
comments.addComment(currentLineComment);
}
return comments;
}
}