1/*
2 * Copyright (C) 2012 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 "core/css/CSSImageSetValue.h"
28
29#include "core/FetchInitiatorTypeNames.h"
30#include "core/css/CSSImageValue.h"
31#include "core/css/CSSPrimitiveValue.h"
32#include "core/dom/Document.h"
33#include "core/fetch/FetchRequest.h"
34#include "core/fetch/ImageResource.h"
35#include "core/fetch/ResourceFetcher.h"
36#include "core/rendering/style/StyleFetchedImageSet.h"
37#include "core/rendering/style/StylePendingImage.h"
38#include "wtf/text/StringBuilder.h"
39
40namespace blink {
41
42CSSImageSetValue::CSSImageSetValue()
43    : CSSValueList(ImageSetClass, CommaSeparator)
44    , m_accessedBestFitImage(false)
45    , m_scaleFactor(1)
46{
47}
48
49CSSImageSetValue::~CSSImageSetValue()
50{
51    if (m_imageSet && m_imageSet->isImageResourceSet())
52        toStyleFetchedImageSet(m_imageSet)->clearImageSetValue();
53}
54
55void CSSImageSetValue::fillImageSet()
56{
57    size_t length = this->length();
58    size_t i = 0;
59    while (i < length) {
60        CSSImageValue* imageValue = toCSSImageValue(item(i));
61        String imageURL = imageValue->url();
62
63        ++i;
64        ASSERT_WITH_SECURITY_IMPLICATION(i < length);
65        CSSValue* scaleFactorValue = item(i);
66        float scaleFactor = toCSSPrimitiveValue(scaleFactorValue)->getFloatValue();
67
68        ImageWithScale image;
69        image.imageURL = imageURL;
70        image.referrer = imageValue->referrer();
71        image.scaleFactor = scaleFactor;
72        m_imagesInSet.append(image);
73        ++i;
74    }
75
76    // Sort the images so that they are stored in order from lowest resolution to highest.
77    std::sort(m_imagesInSet.begin(), m_imagesInSet.end(), CSSImageSetValue::compareByScaleFactor);
78}
79
80CSSImageSetValue::ImageWithScale CSSImageSetValue::bestImageForScaleFactor()
81{
82    ImageWithScale image;
83    size_t numberOfImages = m_imagesInSet.size();
84    for (size_t i = 0; i < numberOfImages; ++i) {
85        image = m_imagesInSet.at(i);
86        if (image.scaleFactor >= m_scaleFactor)
87            return image;
88    }
89    return image;
90}
91
92StyleFetchedImageSet* CSSImageSetValue::cachedImageSet(ResourceFetcher* loader, float deviceScaleFactor, const ResourceLoaderOptions& options)
93{
94    ASSERT(loader);
95
96    m_scaleFactor = deviceScaleFactor;
97
98    if (!m_imagesInSet.size())
99        fillImageSet();
100
101    if (!m_accessedBestFitImage) {
102        // FIXME: In the future, we want to take much more than deviceScaleFactor into acount here.
103        // All forms of scale should be included: Page::pageScaleFactor(), LocalFrame::pageZoomFactor(),
104        // and any CSS transforms. https://bugs.webkit.org/show_bug.cgi?id=81698
105        ImageWithScale image = bestImageForScaleFactor();
106        if (Document* document = loader->document()) {
107            FetchRequest request(ResourceRequest(document->completeURL(image.imageURL)), FetchInitiatorTypeNames::css, options);
108            request.mutableResourceRequest().setHTTPReferrer(image.referrer);
109
110            if (options.corsEnabled == IsCORSEnabled)
111                request.setCrossOriginAccessControl(loader->document()->securityOrigin(), options.allowCredentials, options.credentialsRequested);
112
113            if (ResourcePtr<ImageResource> cachedImage = loader->fetchImage(request)) {
114                m_imageSet = StyleFetchedImageSet::create(cachedImage.get(), image.scaleFactor, this);
115                m_accessedBestFitImage = true;
116            }
117        }
118    }
119
120    return (m_imageSet && m_imageSet->isImageResourceSet()) ? toStyleFetchedImageSet(m_imageSet) : 0;
121}
122
123StyleFetchedImageSet* CSSImageSetValue::cachedImageSet(ResourceFetcher* fetcher, float deviceScaleFactor)
124{
125    return cachedImageSet(fetcher, deviceScaleFactor, ResourceFetcher::defaultResourceOptions());
126}
127
128StyleImage* CSSImageSetValue::cachedOrPendingImageSet(float deviceScaleFactor)
129{
130    if (!m_imageSet) {
131        m_imageSet = StylePendingImage::create(this);
132    } else if (!m_imageSet->isPendingImage()) {
133        // If the deviceScaleFactor has changed, we may not have the best image loaded, so we have to re-assess.
134        if (deviceScaleFactor != m_scaleFactor) {
135            m_accessedBestFitImage = false;
136            m_imageSet = StylePendingImage::create(this);
137        }
138    }
139
140    return m_imageSet.get();
141}
142
143String CSSImageSetValue::customCSSText() const
144{
145    StringBuilder result;
146    result.append("-webkit-image-set(");
147
148    size_t length = this->length();
149    size_t i = 0;
150    while (i < length) {
151        if (i > 0)
152            result.appendLiteral(", ");
153
154        const CSSValue* imageValue = item(i);
155        result.append(imageValue->cssText());
156        result.append(' ');
157
158        ++i;
159        ASSERT_WITH_SECURITY_IMPLICATION(i < length);
160        const CSSValue* scaleFactorValue = item(i);
161        result.append(scaleFactorValue->cssText());
162        // FIXME: Eventually the scale factor should contain it's own unit http://wkb.ug/100120.
163        // For now 'x' is hard-coded in the parser, so we hard-code it here too.
164        result.append('x');
165
166        ++i;
167    }
168
169    result.append(')');
170    return result.toString();
171}
172
173bool CSSImageSetValue::hasFailedOrCanceledSubresources() const
174{
175    if (!m_imageSet || !m_imageSet->isImageResourceSet())
176        return false;
177    if (Resource* cachedResource = toStyleFetchedImageSet(m_imageSet)->cachedImage())
178        return cachedResource->loadFailedOrCanceled();
179    return true;
180}
181
182CSSImageSetValue::CSSImageSetValue(const CSSImageSetValue& cloneFrom)
183    : CSSValueList(cloneFrom)
184    , m_accessedBestFitImage(false)
185    , m_scaleFactor(1)
186{
187    // Non-CSSValueList data is not accessible through CSS OM, no need to clone.
188}
189
190PassRefPtrWillBeRawPtr<CSSImageSetValue> CSSImageSetValue::cloneForCSSOM() const
191{
192    return adoptRefWillBeNoop(new CSSImageSetValue(*this));
193}
194
195} // namespace blink
196