001/*
002  GRANITE DATA SERVICES
003  Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004
005  This file is part of Granite Data Services.
006
007  Granite Data Services is free software; you can redistribute it and/or modify
008  it under the terms of the GNU Library General Public License as published by
009  the Free Software Foundation; either version 2 of the License, or (at your
010  option) any later version.
011
012  Granite Data Services is distributed in the hope that it will be useful, but
013  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014  FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015  for more details.
016
017  You should have received a copy of the GNU Library General Public License
018  along with this library; if not, see <http://www.gnu.org/licenses/>.
019*/
020
021package org.granite.generator.gsp;
022
023import java.io.BufferedReader;
024import java.io.IOException;
025import java.io.Reader;
026import java.io.StringReader;
027import java.util.ArrayList;
028import java.util.List;
029
030import org.granite.generator.gsp.token.Comment;
031import org.granite.generator.gsp.token.Declaration;
032import org.granite.generator.gsp.token.Directive;
033import org.granite.generator.gsp.token.Expression;
034import org.granite.generator.gsp.token.Scriplet;
035import org.granite.generator.gsp.token.TemplateText;
036import org.granite.generator.gsp.token.Token;
037
038/**
039 * @author Franck WOLFF
040 */
041public class Parser {
042
043    private final List<Token> elements = new ArrayList<Token>();
044
045    public Parser() {
046    }
047
048    public List<Token> parse(Reader reader) throws IOException, ParseException {
049        if (reader == null)
050            throw new NullPointerException("reader cannot be null");
051        if (!(reader instanceof StringReader || reader instanceof BufferedReader))
052            reader = new BufferedReader(reader);
053        return parse(read(reader));
054    }
055
056    public List<Token> getElements() {
057        return elements;
058    }
059
060    public void reset() {
061        elements.clear();
062    }
063
064    private List<Token> parse(String template) throws ParseException {
065        if (template == null)
066            throw new NullPointerException("Argument template cannot be null");
067
068        StringBuilder sb = new StringBuilder(64);
069
070        final int length = template.length();
071        boolean inText = true;
072        for (int i = 0; i < length; i++) {
073            char first = inText ? '<' : '%';
074            char last = inText ? '%' : '>';
075            char c = template.charAt(i);
076            boolean appendC = true;
077
078            if (c == first) { // '<' (template text) or '%' (gsp tag content)
079                if (i+1 < length) {
080                    c = template.charAt(i+1);
081                    if (c == last) { // "<%" (template text) or "%>" (gsp tag content)
082                        if (inText)
083                            addTemplateText(i - sb.length(), sb.toString());
084                        else
085                            addScriptingElement(i - sb.length() - 2, sb.toString());
086                        sb.setLength(0);
087                        inText = !inText;
088                        appendC = false;
089                        i++;
090                    } else if (c == '\\') { // "<\" (template text) or "%\" (gsp tag content)
091                        sb.append(first);
092                        for (i += 2; i < length && (c = template.charAt(i)) == '\\'; i++)
093                            sb.append(c);
094                        if (c != last) // add skiped first '/'
095                            sb.append('\\');
096                    } else
097                        c = first;
098                }
099            }
100
101            if (appendC)
102                sb.append(c);
103        }
104
105        if (!inText)
106            throw new ParseException("Missing script section end (\"%>\")");
107
108        addTemplateText(length - sb.length(), sb.toString());
109
110        return elements;
111    }
112
113    private String read(Reader reader) throws IOException {
114        StringBuilder sb = new StringBuilder(1024);
115
116        int pc = -1, c = -1;
117        while((c = reader.read()) != -1) {
118            switch (c) {
119            case '\r': // "\r[\n]" (Windows or Mac)
120                break;
121            case '\n': // "[\r]\n" (Windows or Unix)
122                sb.append('\n');
123                break;
124            default:
125                if (pc == '\r')  // "\r" (Mac)
126                    sb.append('\n');
127                sb.append((char)c);
128                break;
129            }
130            pc = c;
131        }
132
133        return sb.toString();
134    }
135
136    private void addTemplateText(int index, String text) {
137        if (text.length() > 0)
138            elements.add(new TemplateText(index, text));
139    }
140
141    private void addScriptingElement(int index, String text) throws ParseException {
142        if (text.length() == 0)
143            return;
144        char first = text.charAt(0);
145        switch (first) {
146        case '=': // expression
147            elements.add(new Expression(index, text.substring(1).trim()));
148            break;
149        case '!': // variable or method declaration
150            elements.add(new Declaration(index, text.substring(1).trim()));
151            break;
152        case '@': // directive
153            elements.add(new Directive(index, text.substring(1).trim()));
154            break;
155        case '-': // comment ?
156            if (text.startsWith("--") && text.endsWith("--")) {
157                elements.add(new Comment(index, text.substring(2, text.length() - 4)));
158                break;
159            }
160            // fall down (scriplet starting with '-')...
161        default: // scriplet
162            elements.add(new Scriplet(index, text));
163            break;
164        }
165    }
166}