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 "CrossOriginAccessControl.h"
38#include "Document.h"
39#include "Page.h"
40#include "StyleCachedImageSet.h"
41#include "StylePendingImage.h"
42#include <wtf/text/StringBuilder.h>
43
44namespace WebCore {
45
46CSSImageSetValue::CSSImageSetValue()
47    : CSSValueList(ImageSetClass, CommaSeparator)
48    , m_accessedBestFitImage(false)
49    , m_scaleFactor(1)
50{
51}
52
53inline void CSSImageSetValue::detachPendingImage()
54{
55    if (m_imageSet && m_imageSet->isPendingImage())
56        toStylePendingImage(*m_imageSet).detachFromCSSValue();
57}
58
59CSSImageSetValue::~CSSImageSetValue()
60{
61    detachPendingImage();
62
63    if (m_imageSet && m_imageSet->isCachedImageSet())
64        toStyleCachedImageSet(*m_imageSet).clearImageSetValue();
65}
66
67void CSSImageSetValue::fillImageSet()
68{
69    size_t length = this->length();
70    size_t i = 0;
71    while (i < length) {
72        CSSValue* imageValue = item(i);
73        String imageURL = toCSSImageValue(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 = toCSSPrimitiveValue(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, const ResourceLoaderOptions& options)
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)), options);
123        request.setInitiator(cachedResourceRequestInitiators().css);
124        if (options.requestOriginPolicy() == PotentiallyCrossOriginEnabled)
125            updateRequestForAccessControl(request.mutableResourceRequest(), document->securityOrigin(), options.allowCredentials());
126        if (CachedResourceHandle<CachedImage> cachedImage = loader->requestImage(request)) {
127            detachPendingImage();
128            m_imageSet = StyleCachedImageSet::create(cachedImage.get(), image.scaleFactor, this);
129            m_accessedBestFitImage = true;
130        }
131    }
132
133    return (m_imageSet && m_imageSet->isCachedImageSet()) ? toStyleCachedImageSet(m_imageSet.get()) : nullptr;
134}
135
136StyleCachedImageSet* CSSImageSetValue::cachedImageSet(CachedResourceLoader* loader)
137{
138    return cachedImageSet(loader, CachedResourceLoader::defaultCachedResourceOptions());
139}
140
141StyleImage* CSSImageSetValue::cachedOrPendingImageSet(Document& document)
142{
143    if (!m_imageSet)
144        m_imageSet = StylePendingImage::create(this);
145    else if (!m_imageSet->isPendingImage()) {
146        float deviceScaleFactor = 1;
147        if (Page* page = document.page())
148            deviceScaleFactor = page->deviceScaleFactor();
149
150        // If the deviceScaleFactor has changed, we may not have the best image loaded, so we have to re-assess.
151        if (deviceScaleFactor != m_scaleFactor) {
152            m_accessedBestFitImage = false;
153            m_imageSet = StylePendingImage::create(this);
154        }
155    }
156
157    return m_imageSet.get();
158}
159
160String CSSImageSetValue::customCSSText() const
161{
162    StringBuilder result;
163    result.appendLiteral("-webkit-image-set(");
164
165    size_t length = this->length();
166    size_t i = 0;
167    while (i < length) {
168        if (i > 0)
169            result.appendLiteral(", ");
170
171        const CSSValue* imageValue = item(i);
172        result.append(imageValue->cssText());
173        result.append(' ');
174
175        ++i;
176        ASSERT_WITH_SECURITY_IMPLICATION(i < length);
177        const CSSValue* scaleFactorValue = item(i);
178        result.append(scaleFactorValue->cssText());
179        // FIXME: Eventually the scale factor should contain it's own unit http://wkb.ug/100120.
180        // For now 'x' is hard-coded in the parser, so we hard-code it here too.
181        result.append('x');
182
183        ++i;
184    }
185
186    result.append(')');
187    return result.toString();
188}
189
190bool CSSImageSetValue::hasFailedOrCanceledSubresources() const
191{
192    if (!m_imageSet || !m_imageSet->isCachedImageSet())
193        return false;
194    CachedResource* cachedResource = toStyleCachedImageSet(*m_imageSet).cachedImage();
195    if (!cachedResource)
196        return true;
197    return cachedResource->loadFailedOrCanceled();
198}
199
200CSSImageSetValue::CSSImageSetValue(const CSSImageSetValue& cloneFrom)
201    : CSSValueList(cloneFrom)
202    , m_accessedBestFitImage(false)
203    , m_scaleFactor(1)
204{
205    // Non-CSSValueList data is not accessible through CSS OM, no need to clone.
206}
207
208PassRefPtr<CSSImageSetValue> CSSImageSetValue::cloneForCSSOM() const
209{
210    return adoptRef(new CSSImageSetValue(*this));
211}
212
213} // namespace WebCore
214
215#endif // ENABLE(CSS_IMAGE_SET)
216