1/*
2 * Copyright (C) 2012, 2013 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "CSSImageSetValue.h"
28
29#if ENABLE(CSS_IMAGE_SET)
30
31#include "CSSImageValue.h"
32#include "CSSPrimitiveValue.h"
33#include "CachedImage.h"
34#include "CachedResourceLoader.h"
35#include "CachedResourceRequest.h"
36#include "CachedResourceRequestInitiators.h"
37#include "Document.h"
38#include "Page.h"
39#include "StyleCachedImageSet.h"
40#include "StylePendingImage.h"
41#include <wtf/text/StringBuilder.h>
42
43namespace WebCore {
44
45CSSImageSetValue::CSSImageSetValue()
46    : CSSValueList(ImageSetClass, CommaSeparator)
47    , m_accessedBestFitImage(false)
48    , m_scaleFactor(1)
49{
50}
51
52inline void CSSImageSetValue::detachPendingImage()
53{
54    if (m_imageSet && m_imageSet->isPendingImage())
55        static_cast<StylePendingImage&>(*m_imageSet).detachFromCSSValue();
56}
57
58CSSImageSetValue::~CSSImageSetValue()
59{
60    detachPendingImage();
61
62    if (m_imageSet && m_imageSet->isCachedImageSet())
63        static_cast<StyleCachedImageSet*>(m_imageSet.get())->clearImageSetValue();
64}
65
66void CSSImageSetValue::fillImageSet()
67{
68    size_t length = this->length();
69    size_t i = 0;
70    while (i < length) {
71        CSSValue* imageValue = item(i);
72        ASSERT_WITH_SECURITY_IMPLICATION(imageValue->isImageValue());
73        String imageURL = static_cast<CSSImageValue*>(imageValue)->url();
74
75        ++i;
76        ASSERT_WITH_SECURITY_IMPLICATION(i < length);
77        CSSValue* scaleFactorValue = item(i);
78        ASSERT_WITH_SECURITY_IMPLICATION(scaleFactorValue->isPrimitiveValue());
79        float scaleFactor = static_cast<CSSPrimitiveValue*>(scaleFactorValue)->getFloatValue();
80
81        ImageWithScale image;
82        image.imageURL = imageURL;
83        image.scaleFactor = scaleFactor;
84        m_imagesInSet.append(image);
85        ++i;
86    }
87
88    // Sort the images so that they are stored in order from lowest resolution to highest.
89    std::sort(m_imagesInSet.begin(), m_imagesInSet.end(), CSSImageSetValue::compareByScaleFactor);
90}
91
92CSSImageSetValue::ImageWithScale CSSImageSetValue::bestImageForScaleFactor()
93{
94    ImageWithScale image;
95    size_t numberOfImages = m_imagesInSet.size();
96    for (size_t i = 0; i < numberOfImages; ++i) {
97        image = m_imagesInSet.at(i);
98        if (image.scaleFactor >= m_scaleFactor)
99            return image;
100    }
101    return image;
102}
103
104StyleCachedImageSet* CSSImageSetValue::cachedImageSet(CachedResourceLoader* loader)
105{
106    ASSERT(loader);
107
108    Document* document = loader->document();
109    if (Page* page = document->page())
110        m_scaleFactor = page->deviceScaleFactor();
111    else
112        m_scaleFactor = 1;
113
114    if (!m_imagesInSet.size())
115        fillImageSet();
116
117    if (!m_accessedBestFitImage) {
118        // FIXME: In the future, we want to take much more than deviceScaleFactor into acount here.
119        // All forms of scale should be included: Page::pageScaleFactor(), Frame::pageZoomFactor(),
120        // and any CSS transforms. https://bugs.webkit.org/show_bug.cgi?id=81698
121        ImageWithScale image = bestImageForScaleFactor();
122        CachedResourceRequest request(ResourceRequest(document->completeURL(image.imageURL)));
123        request.setInitiator(cachedResourceRequestInitiators().css);
124        if (CachedResourceHandle<CachedImage> cachedImage = loader->requestImage(request)) {
125            detachPendingImage();
126            m_imageSet = StyleCachedImageSet::create(cachedImage.get(), image.scaleFactor, this);
127            m_accessedBestFitImage = true;
128        }
129    }
130
131    return (m_imageSet && m_imageSet->isCachedImageSet()) ? static_cast<StyleCachedImageSet*>(m_imageSet.get()) : 0;
132}
133
134StyleImage* CSSImageSetValue::cachedOrPendingImageSet(Document* document)
135{
136    if (!m_imageSet)
137        m_imageSet = StylePendingImage::create(this);
138    else if (document && !m_imageSet->isPendingImage()) {
139        float deviceScaleFactor = 1;
140        if (Page* page = document->page())
141            deviceScaleFactor = page->deviceScaleFactor();
142
143        // If the deviceScaleFactor has changed, we may not have the best image loaded, so we have to re-assess.
144        if (deviceScaleFactor != m_scaleFactor) {
145            m_accessedBestFitImage = false;
146            m_imageSet = StylePendingImage::create(this);
147        }
148    }
149
150    return m_imageSet.get();
151}
152
153String CSSImageSetValue::customCssText() const
154{
155    StringBuilder result;
156    result.appendLiteral("-webkit-image-set(");
157
158    size_t length = this->length();
159    size_t i = 0;
160    while (i < length) {
161        if (i > 0)
162            result.appendLiteral(", ");
163
164        const CSSValue* imageValue = item(i);
165        result.append(imageValue->cssText());
166        result.append(' ');
167
168        ++i;
169        ASSERT_WITH_SECURITY_IMPLICATION(i < length);
170        const CSSValue* scaleFactorValue = item(i);
171        result.append(scaleFactorValue->cssText());
172        // FIXME: Eventually the scale factor should contain it's own unit http://wkb.ug/100120.
173        // For now 'x' is hard-coded in the parser, so we hard-code it here too.
174        result.append('x');
175
176        ++i;
177    }
178
179    result.append(')');
180    return result.toString();
181}
182
183bool CSSImageSetValue::hasFailedOrCanceledSubresources() const
184{
185    if (!m_imageSet || !m_imageSet->isCachedImageSet())
186        return false;
187    CachedResource* cachedResource = static_cast<StyleCachedImageSet*>(m_imageSet.get())->cachedImage();
188    if (!cachedResource)
189        return true;
190    return cachedResource->loadFailedOrCanceled();
191}
192
193CSSImageSetValue::CSSImageSetValue(const CSSImageSetValue& cloneFrom)
194    : CSSValueList(cloneFrom)
195    , m_accessedBestFitImage(false)
196    , m_scaleFactor(1)
197{
198    // Non-CSSValueList data is not accessible through CSS OM, no need to clone.
199}
200
201PassRefPtr<CSSImageSetValue> CSSImageSetValue::cloneForCSSOM() const
202{
203    return adoptRef(new CSSImageSetValue(*this));
204}
205
206} // namespace WebCore
207
208#endif // ENABLE(CSS_IMAGE_SET)
209