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1 /*
2     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
3     Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
4     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
5     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
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 
23 #ifndef Resource_h
24 #define Resource_h
25 
26 #include "core/fetch/ResourceLoaderOptions.h"
27 #include "platform/Timer.h"
28 #include "platform/network/ResourceError.h"
29 #include "platform/network/ResourceLoadPriority.h"
30 #include "platform/network/ResourceRequest.h"
31 #include "platform/network/ResourceResponse.h"
32 #include "wtf/HashCountedSet.h"
33 #include "wtf/HashSet.h"
34 #include "wtf/OwnPtr.h"
35 #include "wtf/text/WTFString.h"
36 
37 // FIXME(crbug.com/352043): This is temporarily enabled even on RELEASE to diagnose a wild crash.
38 #define ENABLE_RESOURCE_IS_DELETED_CHECK
39 
40 namespace WebCore {
41 
42 struct FetchInitiatorInfo;
43 class MemoryCache;
44 class CachedMetadata;
45 class ResourceClient;
46 class ResourcePtrBase;
47 class ResourceFetcher;
48 class InspectorResource;
49 class ResourceLoader;
50 class SecurityOrigin;
51 class SharedBuffer;
52 
53 // A resource that is held in the cache. Classes who want to use this object should derive
54 // from ResourceClient, to get the function calls in case the requested data has arrived.
55 // This class also does the actual communication with the loader to obtain the resource from the network.
56 class Resource {
57     WTF_MAKE_NONCOPYABLE(Resource); WTF_MAKE_FAST_ALLOCATED;
58     friend class InspectorResource;
59 
60 public:
61     enum Type {
62         MainResource,
63         Image,
64         CSSStyleSheet,
65         Script,
66         Font,
67         Raw,
68         SVGDocument,
69         XSLStyleSheet,
70         LinkPrefetch,
71         LinkSubresource,
72         TextTrack,
73         ImportResource,
74         Media // Audio or video file requested by a HTML5 media element
75     };
76 
77     enum Status {
78         Unknown, // let cache decide what to do with it
79         Pending, // only partially loaded
80         Cached, // regular case
81         LoadError,
82         DecodeError
83     };
84 
85     Resource(const ResourceRequest&, Type);
86     virtual ~Resource();
87 
88     virtual void load(ResourceFetcher*, const ResourceLoaderOptions&);
89 
setEncoding(const String &)90     virtual void setEncoding(const String&) { }
encoding()91     virtual String encoding() const { return String(); }
92     virtual void appendData(const char*, int);
93     virtual void error(Resource::Status);
94 
setNeedsSynchronousCacheHit(bool needsSynchronousCacheHit)95     void setNeedsSynchronousCacheHit(bool needsSynchronousCacheHit) { m_needsSynchronousCacheHit = needsSynchronousCacheHit; }
96 
setResourceError(const ResourceError & error)97     void setResourceError(const ResourceError& error) { m_error = error; }
resourceError()98     const ResourceError& resourceError() const { return m_error; }
99 
setIdentifier(unsigned long identifier)100     void setIdentifier(unsigned long identifier) { m_identifier = identifier; }
identifier()101     unsigned long identifier() const { return m_identifier; }
102 
shouldIgnoreHTTPStatusCodeErrors()103     virtual bool shouldIgnoreHTTPStatusCodeErrors() const { return false; }
104 
resourceRequest()105     ResourceRequest& resourceRequest() { return m_resourceRequest; }
106     const ResourceRequest& lastResourceRequest();
url()107     const KURL& url() const { return m_resourceRequest.url();}
type()108     Type type() const { return static_cast<Type>(m_type); }
options()109     const ResourceLoaderOptions& options() const { return m_options; }
setOptions(const ResourceLoaderOptions & options)110     void setOptions(const ResourceLoaderOptions& options) { m_options = options; }
111 
112     void didChangePriority(ResourceLoadPriority, int intraPriorityValue);
113 
114     void addClient(ResourceClient*);
115     void removeClient(ResourceClient*);
hasClients()116     bool hasClients() const { return !m_clients.isEmpty() || !m_clientsAwaitingCallback.isEmpty(); }
117     bool deleteIfPossible();
118 
119     enum PreloadResult {
120         PreloadNotReferenced,
121         PreloadReferenced,
122         PreloadReferencedWhileLoading,
123         PreloadReferencedWhileComplete
124     };
preloadResult()125     PreloadResult preloadResult() const { return static_cast<PreloadResult>(m_preloadResult); }
126 
127     virtual void didAddClient(ResourceClient*);
didRemoveClient(ResourceClient *)128     virtual void didRemoveClient(ResourceClient*) { }
129     virtual void allClientsRemoved();
130 
count()131     unsigned count() const { return m_clients.size(); }
132 
status()133     Status status() const { return static_cast<Status>(m_status); }
setStatus(Status status)134     void setStatus(Status status) { m_status = status; }
135 
size()136     size_t size() const { return encodedSize() + decodedSize() + overheadSize(); }
encodedSize()137     size_t encodedSize() const { return m_encodedSize; }
decodedSize()138     size_t decodedSize() const { return m_decodedSize; }
139     size_t overheadSize() const;
140 
isLoaded()141     bool isLoaded() const { return !m_loading; } // FIXME. Method name is inaccurate. Loading might not have started yet.
142 
isLoading()143     bool isLoading() const { return m_loading; }
setLoading(bool b)144     void setLoading(bool b) { m_loading = b; }
stillNeedsLoad()145     virtual bool stillNeedsLoad() const { return false; }
146 
loader()147     ResourceLoader* loader() const { return m_loader.get(); }
148 
isImage()149     virtual bool isImage() const { return false; }
ignoreForRequestCount()150     bool ignoreForRequestCount() const
151     {
152         return type() == MainResource
153             || type() == LinkPrefetch
154             || type() == LinkSubresource
155             || type() == Media
156             || type() == Raw
157             || type() == TextTrack;
158     }
159 
160     // Computes the status of an object after loading.
161     // Updates the expire date on the cache entry file
162     void finish(double finishTime = 0.0);
163 
164     // FIXME: Remove the stringless variant once all the callsites' error messages are updated.
165     bool passesAccessControlCheck(SecurityOrigin*);
166     bool passesAccessControlCheck(SecurityOrigin*, String& errorDescription);
167 
168     void clearLoader();
169 
resourceBuffer()170     SharedBuffer* resourceBuffer() const { return m_data.get(); }
171     void setResourceBuffer(PassRefPtr<SharedBuffer>);
172 
173     virtual void willSendRequest(ResourceRequest&, const ResourceResponse&);
174 
updateRequest(const ResourceRequest &)175     virtual void updateRequest(const ResourceRequest&) { }
176     virtual void responseReceived(const ResourceResponse&);
setResponse(const ResourceResponse & response)177     void setResponse(const ResourceResponse& response) { m_response = response; }
response()178     const ResourceResponse& response() const { return m_response; }
179 
180     // Sets the serialized metadata retrieved from the platform's cache.
181     void setSerializedCachedMetadata(const char*, size_t);
182 
183     // Caches the given metadata in association with this resource and suggests
184     // that the platform persist it. The dataTypeID is a pseudo-randomly chosen
185     // identifier that is used to distinguish data generated by the caller.
186     void setCachedMetadata(unsigned dataTypeID, const char*, size_t);
187 
188     // Returns cached metadata of the given type associated with this resource.
189     CachedMetadata* cachedMetadata(unsigned dataTypeID) const;
190 
191     bool hasOneHandle() const;
192     bool canDelete() const;
193 
194     // List of acceptable MIME types separated by ",".
195     // A MIME type may contain a wildcard, e.g. "text/*".
accept()196     AtomicString accept() const { return m_accept; }
setAccept(const AtomicString & accept)197     void setAccept(const AtomicString& accept) { m_accept = accept; }
198 
wasCanceled()199     bool wasCanceled() const { return m_error.isCancellation(); }
errorOccurred()200     bool errorOccurred() const { return m_status == LoadError || m_status == DecodeError; }
loadFailedOrCanceled()201     bool loadFailedOrCanceled() { return !m_error.isNull(); }
202 
dataBufferingPolicy()203     DataBufferingPolicy dataBufferingPolicy() const { return m_options.dataBufferingPolicy; }
204     void setDataBufferingPolicy(DataBufferingPolicy);
205 
isPreloaded()206     bool isPreloaded() const { return m_preloadCount; }
increasePreloadCount()207     void increasePreloadCount() { ++m_preloadCount; }
decreasePreloadCount()208     void decreasePreloadCount() { ASSERT(m_preloadCount); --m_preloadCount; }
209 
210     void registerHandle(ResourcePtrBase* h);
211     void unregisterHandle(ResourcePtrBase* h);
212 
213     bool canReuseRedirectChain();
214     bool mustRevalidateDueToCacheHeaders();
215     bool canUseCacheValidator();
isCacheValidator()216     bool isCacheValidator() const { return m_resourceToRevalidate; }
resourceToRevalidate()217     Resource* resourceToRevalidate() const { return m_resourceToRevalidate; }
218     void setResourceToRevalidate(Resource*);
219     bool hasCacheControlNoStoreHeader();
220 
221     bool isPurgeable() const;
222     bool wasPurged() const;
223     bool lock();
224 
didSendData(unsigned long long,unsigned long long)225     virtual void didSendData(unsigned long long /* bytesSent */, unsigned long long /* totalBytesToBeSent */) { }
didDownloadData(int)226     virtual void didDownloadData(int) { }
227 
loadFinishTime()228     double loadFinishTime() const { return m_loadFinishTime; }
229 
canReuse(const ResourceRequest &)230     virtual bool canReuse(const ResourceRequest&) const { return true; }
231 
232     // Used by the MemoryCache to reduce the memory consumption of the entry.
233     void prune();
234 
235     static const char* resourceTypeToString(Type, const FetchInitiatorInfo&);
236 
237 #ifdef ENABLE_RESOURCE_IS_DELETED_CHECK
assertAlive()238     void assertAlive() const { RELEASE_ASSERT(!m_deleted); }
239 #else
assertAlive()240     void assertAlive() const { }
241 #endif
242 
243 protected:
244     virtual void checkNotify();
245     virtual void finishOnePart();
246 
247     // Normal resource pointers will silently switch what Resource* they reference when we
248     // successfully revalidated the resource. We need a way to guarantee that the Resource
249     // that received the 304 response survives long enough to switch everything over to the
250     // revalidatedresource. The normal mechanisms for keeping a Resource alive externally
251     // (ResourcePtrs and ResourceClients registering themselves) don't work in this case, so
252     // have a separate internal protector).
253     class InternalResourcePtr {
254     public:
InternalResourcePtr(Resource * resource)255         explicit InternalResourcePtr(Resource* resource)
256             : m_resource(resource)
257         {
258             m_resource->incrementProtectorCount();
259         }
260 
~InternalResourcePtr()261         ~InternalResourcePtr()
262         {
263             m_resource->decrementProtectorCount();
264             m_resource->deleteIfPossible();
265         }
266     private:
267         Resource* m_resource;
268     };
269 
incrementProtectorCount()270     void incrementProtectorCount() { m_protectorCount++; }
decrementProtectorCount()271     void decrementProtectorCount() { m_protectorCount--; }
272 
273     void setEncodedSize(size_t);
274     void setDecodedSize(size_t);
275     void didAccessDecodedData();
276 
277     virtual void switchClientsToRevalidatedResource();
278     void clearResourceToRevalidate();
279     void updateResponseAfterRevalidation(const ResourceResponse& validatingResponse);
280 
281     void finishPendingClients();
282 
283     HashCountedSet<ResourceClient*> m_clients;
284     HashCountedSet<ResourceClient*> m_clientsAwaitingCallback;
285 
286     class ResourceCallback {
287     public:
288         static ResourceCallback* callbackHandler();
289         void schedule(Resource*);
290         void cancel(Resource*);
291         bool isScheduled(Resource*) const;
292     private:
293         ResourceCallback();
294         void timerFired(Timer<ResourceCallback>*);
295         Timer<ResourceCallback> m_callbackTimer;
296         HashSet<Resource*> m_resourcesWithPendingClients;
297     };
298 
hasClient(ResourceClient * client)299     bool hasClient(ResourceClient* client) { return m_clients.contains(client) || m_clientsAwaitingCallback.contains(client); }
300 
301     struct RedirectPair {
302     public:
RedirectPairRedirectPair303         explicit RedirectPair(const ResourceRequest& request, const ResourceResponse& redirectResponse)
304             : m_request(request)
305             , m_redirectResponse(redirectResponse)
306         {
307         }
308 
309         ResourceRequest m_request;
310         ResourceResponse m_redirectResponse;
311     };
redirectChain()312     const Vector<RedirectPair>& redirectChain() const { return m_redirectChain; }
313 
isSafeToUnlock()314     virtual bool isSafeToUnlock() const { return false; }
destroyDecodedDataIfPossible()315     virtual void destroyDecodedDataIfPossible() { }
316 
317     ResourceRequest m_resourceRequest;
318     AtomicString m_accept;
319     RefPtr<ResourceLoader> m_loader;
320     ResourceLoaderOptions m_options;
321 
322     ResourceResponse m_response;
323     double m_responseTimestamp;
324 
325     RefPtr<SharedBuffer> m_data;
326     Timer<Resource> m_cancelTimer;
327 
328 private:
329     bool addClientToSet(ResourceClient*);
330     void cancelTimerFired(Timer<Resource>*);
331 
332     void revalidationSucceeded(const ResourceResponse&);
333     void revalidationFailed();
334 
335     bool unlock();
336 
337     bool hasRightHandleCountApartFromCache(unsigned targetCount) const;
338 
339     void failBeforeStarting();
340 
341     String m_fragmentIdentifierForRequest;
342 
343     RefPtr<CachedMetadata> m_cachedMetadata;
344 
345     ResourceError m_error;
346 
347     double m_loadFinishTime;
348 
349     unsigned long m_identifier;
350 
351     size_t m_encodedSize;
352     size_t m_decodedSize;
353     unsigned m_handleCount;
354     unsigned m_preloadCount;
355     unsigned m_protectorCount;
356 
357     unsigned m_preloadResult : 2; // PreloadResult
358     unsigned m_requestedFromNetworkingLayer : 1;
359 
360     unsigned m_loading : 1;
361 
362     unsigned m_switchingClientsToRevalidatedResource : 1;
363 
364     unsigned m_type : 4; // Type
365     unsigned m_status : 3; // Status
366 
367     unsigned m_wasPurged : 1;
368 
369     unsigned m_needsSynchronousCacheHit : 1;
370 
371 #ifdef ENABLE_RESOURCE_IS_DELETED_CHECK
372     bool m_deleted;
373 #endif
374 
375     // If this field is non-null we are using the resource as a proxy for checking whether an existing resource is still up to date
376     // using HTTP If-Modified-Since/If-None-Match headers. If the response is 304 all clients of this resource are moved
377     // to to be clients of m_resourceToRevalidate and the resource is deleted. If not, the field is zeroed and this
378     // resources becomes normal resource load.
379     Resource* m_resourceToRevalidate;
380 
381     // If this field is non-null, the resource has a proxy for checking whether it is still up to date (see m_resourceToRevalidate).
382     Resource* m_proxyResource;
383 
384     // These handles will need to be updated to point to the m_resourceToRevalidate in case we get 304 response.
385     HashSet<ResourcePtrBase*> m_handlesToRevalidate;
386 
387     // Ordered list of all redirects followed while fetching this resource.
388     Vector<RedirectPair> m_redirectChain;
389 };
390 
391 #if !LOG_DISABLED
392 // Intended to be used in LOG statements.
393 const char* ResourceTypeName(Resource::Type);
394 #endif
395 
396 #define DEFINE_RESOURCE_TYPE_CASTS(typeName) \
397     DEFINE_TYPE_CASTS(typeName##Resource, Resource, resource, resource->type() == Resource::typeName, resource.type() == Resource::typeName); \
398     inline typeName##Resource* to##typeName##Resource(const ResourcePtr<Resource>& ptr) { return to##typeName##Resource(ptr.get()); }
399 
400 }
401 
402 #endif
403