1/*
2 * (C) 1999-2003 Lars Knoll (knoll@kde.org)
3 * Copyright (C) 2004, 2006, 2010 Apple Inc. All rights reserved.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public License
16 * along with this library; see the file COPYING.LIB.  If not, write to
17 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
19 */
20#include "config.h"
21#include "MediaList.h"
22
23#include "CSSImportRule.h"
24#include "CSSParser.h"
25#include "CSSStyleSheet.h"
26#include "ExceptionCode.h"
27#include "MediaQuery.h"
28#include "MediaQueryExp.h"
29
30namespace WebCore {
31
32/* MediaList is used to store 3 types of media related entities which mean the same:
33 * Media Queries, Media Types and Media Descriptors.
34 * Currently MediaList always tries to parse media queries and if parsing fails,
35 * tries to fallback to Media Descriptors if m_fallback flag is set.
36 * Slight problem with syntax error handling:
37 * CSS 2.1 Spec (http://www.w3.org/TR/CSS21/media.html)
38 * specifies that failing media type parsing is a syntax error
39 * CSS 3 Media Queries Spec (http://www.w3.org/TR/css3-mediaqueries/)
40 * specifies that failing media query is a syntax error
41 * HTML 4.01 spec (http://www.w3.org/TR/REC-html40/present/styles.html#adef-media)
42 * specifies that Media Descriptors should be parsed with forward-compatible syntax
43 * DOM Level 2 Style Sheet spec (http://www.w3.org/TR/DOM-Level-2-Style/)
44 * talks about MediaList.mediaText and refers
45 *   -  to Media Descriptors of HTML 4.0 in context of StyleSheet
46 *   -  to Media Types of CSS 2.0 in context of CSSMediaRule and CSSImportRule
47 *
48 * These facts create situation where same (illegal) media specification may result in
49 * different parses depending on whether it is media attr of style element or part of
50 * css @media rule.
51 * <style media="screen and resolution > 40dpi"> ..</style> will be enabled on screen devices where as
52 * @media screen and resolution > 40dpi {..} will not.
53 * This gets more counter-intuitive in JavaScript:
54 * document.styleSheets[0].media.mediaText = "screen and resolution > 40dpi" will be ok and
55 * enabled, while
56 * document.styleSheets[0].cssRules[0].media.mediaText = "screen and resolution > 40dpi" will
57 * throw SYNTAX_ERR exception.
58 */
59
60MediaList::MediaList(CSSStyleSheet* parentSheet, bool fallbackToDescriptor)
61    : StyleBase(parentSheet)
62    , m_fallback(fallbackToDescriptor)
63{
64}
65
66MediaList::MediaList(CSSStyleSheet* parentSheet, const String& media, bool fallbackToDescriptor)
67    : StyleBase(parentSheet)
68    , m_fallback(fallbackToDescriptor)
69{
70    ExceptionCode ec = 0;
71    setMediaText(media, ec);
72    // FIXME: parsing can fail. The problem with failing constructor is that
73    // we would need additional flag saying MediaList is not valid
74    // Parse can fail only when fallbackToDescriptor == false, i.e when HTML4 media descriptor
75    // forward-compatible syntax is not in use.
76    // DOMImplementationCSS seems to mandate that media descriptors are used
77    // for both html and svg, even though svg:style doesn't use media descriptors
78    // Currently the only places where parsing can fail are
79    // creating <svg:style>, creating css media / import rules from js
80    if (ec)
81        setMediaText("invalid", ec);
82}
83
84MediaList::MediaList(CSSImportRule* parentRule, const String& media)
85    : StyleBase(parentRule)
86    , m_fallback(false)
87{
88    ExceptionCode ec = 0;
89    setMediaText(media, ec);
90    if (ec)
91        setMediaText("invalid", ec);
92}
93
94MediaList::~MediaList()
95{
96    deleteAllValues(m_queries);
97}
98
99static String parseMediaDescriptor(const String& s)
100{
101    int len = s.length();
102
103    // http://www.w3.org/TR/REC-html40/types.html#type-media-descriptors
104    // "Each entry is truncated just before the first character that isn't a
105    // US ASCII letter [a-zA-Z] (ISO 10646 hex 41-5a, 61-7a), digit [0-9] (hex 30-39),
106    // or hyphen (hex 2d)."
107    int i;
108    unsigned short c;
109    for (i = 0; i < len; ++i) {
110        c = s[i];
111        if (! ((c >= 'a' && c <= 'z')
112            || (c >= 'A' && c <= 'Z')
113            || (c >= '1' && c <= '9')
114            || (c == '-')))
115            break;
116    }
117    return s.left(i);
118}
119
120void MediaList::deleteMedium(const String& oldMedium, ExceptionCode& ec)
121{
122    RefPtr<MediaList> tempMediaList = MediaList::create();
123    CSSParser p(true);
124
125    MediaQuery* oldQuery = 0;
126    OwnPtr<MediaQuery> createdQuery;
127
128    if (p.parseMediaQuery(tempMediaList.get(), oldMedium)) {
129        if (tempMediaList->m_queries.size() > 0)
130            oldQuery = tempMediaList->m_queries[0];
131    } else if (m_fallback) {
132        String medium = parseMediaDescriptor(oldMedium);
133        if (!medium.isNull()) {
134            createdQuery = adoptPtr(new MediaQuery(MediaQuery::None, medium, 0));
135            oldQuery = createdQuery.get();
136        }
137    }
138
139    // DOM Style Sheets spec doesn't allow SYNTAX_ERR to be thrown in deleteMedium
140    ec = NOT_FOUND_ERR;
141
142    if (oldQuery) {
143        for (size_t i = 0; i < m_queries.size(); ++i) {
144            MediaQuery* a = m_queries[i];
145            if (*a == *oldQuery) {
146                m_queries.remove(i);
147                delete a;
148                ec = 0;
149                break;
150            }
151        }
152    }
153
154    if (!ec)
155        notifyChanged();
156}
157
158String MediaList::mediaText() const
159{
160    String text("");
161
162    bool first = true;
163    for (size_t i = 0; i < m_queries.size(); ++i) {
164        if (!first)
165            text += ", ";
166        else
167            first = false;
168        text += m_queries[i]->cssText();
169    }
170
171    return text;
172}
173
174void MediaList::setMediaText(const String& value, ExceptionCode& ec)
175{
176    RefPtr<MediaList> tempMediaList = MediaList::create();
177    CSSParser p(true);
178
179    Vector<String> list;
180    value.split(',', list);
181    Vector<String>::const_iterator end = list.end();
182    for (Vector<String>::const_iterator it = list.begin(); it != end; ++it) {
183        String medium = (*it).stripWhiteSpace();
184        if (!medium.isEmpty()) {
185            if (!p.parseMediaQuery(tempMediaList.get(), medium)) {
186                if (m_fallback) {
187                    String mediaDescriptor = parseMediaDescriptor(medium);
188                    if (!mediaDescriptor.isNull())
189                        tempMediaList->m_queries.append(new MediaQuery(MediaQuery::None, mediaDescriptor, 0));
190                } else {
191                    ec = SYNTAX_ERR;
192                    return;
193                }
194            }
195        } else if (!m_fallback) {
196            ec = SYNTAX_ERR;
197            return;
198        }
199    }
200    // ",,,," falls straight through, but is not valid unless fallback
201    if (!m_fallback && list.begin() == list.end()) {
202        String s = value.stripWhiteSpace();
203        if (!s.isEmpty()) {
204            ec = SYNTAX_ERR;
205            return;
206        }
207    }
208
209    ec = 0;
210    deleteAllValues(m_queries);
211    m_queries = tempMediaList->m_queries;
212    tempMediaList->m_queries.clear();
213    notifyChanged();
214}
215
216String MediaList::item(unsigned index) const
217{
218    if (index < m_queries.size()) {
219        MediaQuery* query = m_queries[index];
220        return query->cssText();
221    }
222
223    return String();
224}
225
226void MediaList::appendMedium(const String& newMedium, ExceptionCode& ec)
227{
228    ec = INVALID_CHARACTER_ERR;
229    CSSParser p(true);
230    if (p.parseMediaQuery(this, newMedium)) {
231        ec = 0;
232    } else if (m_fallback) {
233        String medium = parseMediaDescriptor(newMedium);
234        if (!medium.isNull()) {
235            m_queries.append(new MediaQuery(MediaQuery::None, medium, 0));
236            ec = 0;
237        }
238    }
239
240    if (!ec)
241        notifyChanged();
242}
243
244void MediaList::appendMediaQuery(PassOwnPtr<MediaQuery> mediaQuery)
245{
246    m_queries.append(mediaQuery.leakPtr());
247}
248
249void MediaList::notifyChanged()
250{
251    for (StyleBase* p = parent(); p; p = p->parent()) {
252        if (p->isCSSStyleSheet())
253            return static_cast<CSSStyleSheet*>(p)->styleSheetChanged();
254    }
255}
256
257}
258