CSSPreloadScanner.cpp revision cad810f21b803229eb11403f9209855525a25d57 
1/*
2 * Copyright (C) 2008, 2010 Apple Inc. All Rights Reserved.
3 * Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
4 * Copyright (C) 2010 Google Inc. All Rights Reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
23 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include "config.h"
29#include "CSSPreloadScanner.h"
30
31#include "CachedCSSStyleSheet.h"
32#include "CachedResourceLoader.h"
33#include "Document.h"
34#include "HTMLParserIdioms.h"
35#include "HTMLToken.h"
36
37namespace WebCore {
38
39CSSPreloadScanner::CSSPreloadScanner(Document* document)
40    : m_state(Initial)
41    , m_document(document)
42{
43}
44
45void CSSPreloadScanner::reset()
46{
47    m_state = Initial;
48    m_rule.clear();
49    m_ruleValue.clear();
50}
51
52void CSSPreloadScanner::scan(const HTMLToken& token, bool scanningBody)
53{
54    m_scanningBody = scanningBody;
55
56    const HTMLToken::DataVector& characters = token.characters();
57    for (HTMLToken::DataVector::const_iterator iter = characters.begin(); iter != characters.end(); ++iter)
58        tokenize(*iter);
59}
60
61inline void CSSPreloadScanner::tokenize(UChar c)
62{
63    // We are just interested in @import rules, no need for real tokenization here
64    // Searching for other types of resources is probably low payoff.
65    switch (m_state) {
66    case Initial:
67        if (c == '@')
68            m_state = RuleStart;
69        else if (c == '/')
70            m_state = MaybeComment;
71        break;
72    case MaybeComment:
73        if (c == '*')
74            m_state = Comment;
75        else
76            m_state = Initial;
77        break;
78    case Comment:
79        if (c == '*')
80            m_state = MaybeCommentEnd;
81        break;
82    case MaybeCommentEnd:
83        if (c == '/')
84            m_state = Initial;
85        else if (c == '*')
86            ;
87        else
88            m_state = Comment;
89        break;
90    case RuleStart:
91        if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')) {
92            m_rule.clear();
93            m_ruleValue.clear();
94            m_rule.append(c);
95            m_state = Rule;
96        } else
97            m_state = Initial;
98        break;
99    case Rule:
100        if (isHTMLSpace(c))
101            m_state = AfterRule;
102        else if (c == ';')
103            m_state = Initial;
104        else
105            m_rule.append(c);
106        break;
107    case AfterRule:
108        if (isHTMLSpace(c))
109            ;
110        else if (c == ';')
111            m_state = Initial;
112        else {
113            m_state = RuleValue;
114            m_ruleValue.append(c);
115        }
116        break;
117    case RuleValue:
118        if (isHTMLSpace(c))
119            m_state = AfterRuleValue;
120        else if (c == ';') {
121            emitRule();
122            m_state = Initial;
123        } else
124            m_ruleValue.append(c);
125        break;
126    case AfterRuleValue:
127        if (isHTMLSpace(c))
128            ;
129        else if (c == ';') {
130            emitRule();
131            m_state = Initial;
132        } else {
133            // FIXME: media rules
134            m_state = Initial;
135        }
136        break;
137    }
138}
139
140static String parseCSSStringOrURL(const UChar* characters, size_t length)
141{
142    size_t offset = 0;
143    size_t reducedLength = length;
144
145    while (reducedLength && isHTMLSpace(characters[offset])) {
146        ++offset;
147        --reducedLength;
148    }
149    while (reducedLength && isHTMLSpace(characters[offset + reducedLength - 1]))
150        --reducedLength;
151
152    if (reducedLength >= 5
153            && (characters[offset] == 'u' || characters[offset] == 'U')
154            && (characters[offset + 1] == 'r' || characters[offset + 1] == 'R')
155            && (characters[offset + 2] == 'l' || characters[offset + 2] == 'L')
156            && characters[offset + 3] == '('
157            && characters[offset + reducedLength - 1] == ')') {
158        offset += 4;
159        reducedLength -= 5;
160    }
161
162    while (reducedLength && isHTMLSpace(characters[offset])) {
163        ++offset;
164        --reducedLength;
165    }
166    while (reducedLength && isHTMLSpace(characters[offset + reducedLength - 1]))
167        --reducedLength;
168
169    if (reducedLength < 2 || characters[offset] != characters[offset + reducedLength - 1] || !(characters[offset] == '\'' || characters[offset] == '"'))
170        return String();
171    offset++;
172    reducedLength -= 2;
173
174    while (reducedLength && isHTMLSpace(characters[offset])) {
175        ++offset;
176        --reducedLength;
177    }
178    while (reducedLength && isHTMLSpace(characters[offset + reducedLength - 1]))
179        --reducedLength;
180
181    return String(characters + offset, reducedLength);
182}
183
184void CSSPreloadScanner::emitRule()
185{
186    if (equalIgnoringCase("import", m_rule.data(), m_rule.size())) {
187        String value = parseCSSStringOrURL(m_ruleValue.data(), m_ruleValue.size());
188        if (!value.isEmpty())
189            m_document->cachedResourceLoader()->preload(CachedResource::CSSStyleSheet, value, String(), m_scanningBody);
190    }
191    m_rule.clear();
192    m_ruleValue.clear();
193}
194
195}
196