1/*
2    Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
3    Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
4    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
5    Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
6
7    This library is free software; you can redistribute it and/or
8    modify it under the terms of the GNU Library General Public
9    License as published by the Free Software Foundation; either
10    version 2 of the License, or (at your option) any later version.
11
12    This library is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15    Library General Public License for more details.
16
17    You should have received a copy of the GNU Library General Public License
18    along with this library; see the file COPYING.LIB.  If not, write to
19    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
20    Boston, MA 02110-1301, USA.
21
22    This class provides all functionality needed for loading images, style sheets and html
23    pages from the web. It has a memory cache for these objects.
24*/
25
26#ifndef CachedResourceLoader_h
27#define CachedResourceLoader_h
28
29#include "CachePolicy.h"
30#include "CachedResource.h"
31#include "CachedResourceHandle.h"
32#include "CachedResourceRequest.h"
33#include "ResourceLoadPriority.h"
34#include "Timer.h"
35#include <wtf/Deque.h>
36#include <wtf/HashMap.h>
37#include <wtf/HashSet.h>
38#include <wtf/ListHashSet.h>
39#include <wtf/text/StringHash.h>
40
41namespace WebCore {
42
43class CachedCSSStyleSheet;
44class CachedSVGDocument;
45class CachedFont;
46class CachedImage;
47class CachedRawResource;
48class CachedScript;
49class CachedShader;
50class CachedTextTrack;
51class CachedXSLStyleSheet;
52class Document;
53class DocumentLoader;
54class Frame;
55class ImageLoader;
56class KURL;
57
58// The CachedResourceLoader provides a per-context interface to the MemoryCache
59// and enforces a bunch of security checks and rules for resource revalidation.
60// Its lifetime is roughly per-DocumentLoader, in that it is generally created
61// in the DocumentLoader constructor and loses its ability to generate network
62// requests when the DocumentLoader is destroyed. Documents also hold a
63// RefPtr<CachedResourceLoader> for their lifetime (and will create one if they
64// are initialized without a Frame), so a Document can keep a CachedResourceLoader
65// alive past detach if scripts still reference the Document.
66class CachedResourceLoader : public RefCounted<CachedResourceLoader> {
67    WTF_MAKE_NONCOPYABLE(CachedResourceLoader); WTF_MAKE_FAST_ALLOCATED;
68friend class ImageLoader;
69friend class ResourceCacheValidationSuppressor;
70
71public:
72    static PassRefPtr<CachedResourceLoader> create(DocumentLoader* documentLoader) { return adoptRef(new CachedResourceLoader(documentLoader)); }
73    ~CachedResourceLoader();
74
75    CachedResourceHandle<CachedImage> requestImage(CachedResourceRequest&);
76    CachedResourceHandle<CachedCSSStyleSheet> requestCSSStyleSheet(CachedResourceRequest&);
77    CachedResourceHandle<CachedCSSStyleSheet> requestUserCSSStyleSheet(CachedResourceRequest&);
78    CachedResourceHandle<CachedScript> requestScript(CachedResourceRequest&);
79    CachedResourceHandle<CachedFont> requestFont(CachedResourceRequest&);
80    CachedResourceHandle<CachedRawResource> requestRawResource(CachedResourceRequest&);
81    CachedResourceHandle<CachedRawResource> requestMainResource(CachedResourceRequest&);
82
83#if ENABLE(SVG)
84    CachedResourceHandle<CachedSVGDocument> requestSVGDocument(CachedResourceRequest&);
85#endif
86#if ENABLE(XSLT)
87    CachedResourceHandle<CachedXSLStyleSheet> requestXSLStyleSheet(CachedResourceRequest&);
88#endif
89#if ENABLE(LINK_PREFETCH)
90    CachedResourceHandle<CachedResource> requestLinkResource(CachedResource::Type, CachedResourceRequest&);
91#endif
92#if ENABLE(VIDEO_TRACK)
93    CachedResourceHandle<CachedTextTrack> requestTextTrack(CachedResourceRequest&);
94#endif
95#if ENABLE(CSS_SHADERS)
96    CachedResourceHandle<CachedShader> requestShader(CachedResourceRequest&);
97#endif
98
99    // Logs an access denied message to the console for the specified URL.
100    void printAccessDeniedMessage(const KURL& url) const;
101
102    CachedResource* cachedResource(const String& url) const;
103    CachedResource* cachedResource(const KURL& url) const;
104
105    typedef HashMap<String, CachedResourceHandle<CachedResource> > DocumentResourceMap;
106    const DocumentResourceMap& allCachedResources() const { return m_documentResources; }
107
108    bool autoLoadImages() const { return m_autoLoadImages; }
109    void setAutoLoadImages(bool);
110
111    void setImagesEnabled(bool);
112
113    bool shouldDeferImageLoad(const KURL&) const;
114
115    CachePolicy cachePolicy(CachedResource::Type) const;
116
117    Frame* frame() const; // Can be null
118    Document* document() const { return m_document; } // Can be null
119    void setDocument(Document* document) { m_document = document; }
120    void clearDocumentLoader() { m_documentLoader = 0; }
121
122    void removeCachedResource(CachedResource*) const;
123    void loadDone(CachedResource*);
124    void garbageCollectDocumentResources();
125
126    void incrementRequestCount(const CachedResource*);
127    void decrementRequestCount(const CachedResource*);
128    int requestCount() const { return m_requestCount; }
129
130    bool isPreloaded(const String& urlString) const;
131    void clearPreloads();
132    void clearPendingPreloads();
133    void preload(CachedResource::Type, CachedResourceRequest&, const String& charset);
134    void checkForPendingPreloads();
135    void printPreloadStats();
136    bool canRequest(CachedResource::Type, const KURL&, bool forPreload = false);
137
138    static const ResourceLoaderOptions& defaultCachedResourceOptions();
139
140private:
141    explicit CachedResourceLoader(DocumentLoader*);
142
143    CachedResourceHandle<CachedResource> requestResource(CachedResource::Type, CachedResourceRequest&);
144    CachedResourceHandle<CachedResource> revalidateResource(const CachedResourceRequest&, CachedResource*);
145    CachedResourceHandle<CachedResource> loadResource(CachedResource::Type, CachedResourceRequest&, const String& charset);
146#if ENABLE(RESOURCE_TIMING)
147    void storeResourceTimingInitiatorInformation(const CachedResourceHandle<CachedResource>&, const CachedResourceRequest&);
148#endif
149    void requestPreload(CachedResource::Type, CachedResourceRequest&, const String& charset);
150
151    enum RevalidationPolicy { Use, Revalidate, Reload, Load };
152    RevalidationPolicy determineRevalidationPolicy(CachedResource::Type, ResourceRequest&, bool forPreload, CachedResource* existingResource, CachedResourceRequest::DeferOption) const;
153
154    bool shouldContinueAfterNotifyingLoadedFromMemoryCache(const CachedResourceRequest&, CachedResource*);
155    bool checkInsecureContent(CachedResource::Type, const KURL&) const;
156
157    void garbageCollectDocumentResourcesTimerFired(Timer<CachedResourceLoader>*);
158    void performPostLoadActions();
159
160    bool clientDefersImage(const KURL&) const;
161    void reloadImagesIfNotDeferred();
162
163    HashSet<String> m_validatedURLs;
164    mutable DocumentResourceMap m_documentResources;
165    Document* m_document;
166    DocumentLoader* m_documentLoader;
167
168    int m_requestCount;
169
170    OwnPtr<ListHashSet<CachedResource*> > m_preloads;
171    struct PendingPreload {
172        CachedResource::Type m_type;
173        CachedResourceRequest m_request;
174        String m_charset;
175    };
176    Deque<PendingPreload> m_pendingPreloads;
177
178    Timer<CachedResourceLoader> m_garbageCollectDocumentResourcesTimer;
179
180#if ENABLE(RESOURCE_TIMING)
181    struct InitiatorInfo {
182        AtomicString name;
183        double startTime;
184    };
185    HashMap<CachedResource*, InitiatorInfo> m_initiatorMap;
186#endif
187
188    // 29 bits left
189    bool m_autoLoadImages : 1;
190    bool m_imagesEnabled : 1;
191    bool m_allowStaleResources : 1;
192};
193
194class ResourceCacheValidationSuppressor {
195    WTF_MAKE_NONCOPYABLE(ResourceCacheValidationSuppressor);
196    WTF_MAKE_FAST_ALLOCATED;
197public:
198    ResourceCacheValidationSuppressor(CachedResourceLoader* loader)
199        : m_loader(loader)
200        , m_previousState(false)
201    {
202        if (m_loader) {
203            m_previousState = m_loader->m_allowStaleResources;
204            m_loader->m_allowStaleResources = true;
205        }
206    }
207    ~ResourceCacheValidationSuppressor()
208    {
209        if (m_loader)
210            m_loader->m_allowStaleResources = m_previousState;
211    }
212private:
213    CachedResourceLoader* m_loader;
214    bool m_previousState;
215};
216
217} // namespace WebCore
218
219#endif
220