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
40namespace blink {
41
42struct FetchInitiatorInfo;
43class MemoryCache;
44class CachedMetadata;
45class ResourceClient;
46class ResourcePtrBase;
47class ResourceFetcher;
48class InspectorResource;
49class ResourceLoader;
50class SecurityOrigin;
51class 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.
56class Resource : public NoBaseWillBeGarbageCollectedFinalized<Resource> {
57    WTF_MAKE_NONCOPYABLE(Resource); WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
58    friend class InspectorResource;
59
60public:
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    enum MetadataCacheType {
86        SendToPlatform, // send cache data to blink::Platform::cacheMetadata
87        CacheLocally // cache only in Resource's member variables
88    };
89
90    Resource(const ResourceRequest&, Type);
91#if ENABLE(OILPAN)
92    virtual ~Resource();
93#else
94protected:
95    // Only deleteIfPossible should delete this.
96    virtual ~Resource();
97public:
98#endif
99    virtual void dispose();
100    virtual void trace(Visitor*);
101    static unsigned instanceCount() { return s_instanceCount; }
102
103    virtual void load(ResourceFetcher*, const ResourceLoaderOptions&);
104
105    virtual void setEncoding(const String&) { }
106    virtual String encoding() const { return String(); }
107    virtual void appendData(const char*, int);
108    virtual void error(Resource::Status);
109
110    void setNeedsSynchronousCacheHit(bool needsSynchronousCacheHit) { m_needsSynchronousCacheHit = needsSynchronousCacheHit; }
111
112    void setResourceError(const ResourceError& error) { m_error = error; }
113    const ResourceError& resourceError() const { return m_error; }
114
115    void setIdentifier(unsigned long identifier) { m_identifier = identifier; }
116    unsigned long identifier() const { return m_identifier; }
117
118    virtual bool shouldIgnoreHTTPStatusCodeErrors() const { return false; }
119
120    ResourceRequest& mutableResourceRequest() { return m_resourceRequest; }
121    const ResourceRequest& resourceRequest() const { return m_resourceRequest; }
122    const ResourceRequest& lastResourceRequest() const;
123
124    const KURL& url() const { return m_resourceRequest.url();}
125    Type type() const { return static_cast<Type>(m_type); }
126    const ResourceLoaderOptions& options() const { return m_options; }
127    void setOptions(const ResourceLoaderOptions& options) { m_options = options; }
128
129    void didChangePriority(ResourceLoadPriority, int intraPriorityValue);
130
131    void addClient(ResourceClient*);
132    void removeClient(ResourceClient*);
133    bool hasClients() const { return !m_clients.isEmpty() || !m_clientsAwaitingCallback.isEmpty(); }
134    bool deleteIfPossible();
135
136    enum PreloadResult {
137        PreloadNotReferenced,
138        PreloadReferenced,
139        PreloadReferencedWhileLoading,
140        PreloadReferencedWhileComplete
141    };
142    PreloadResult preloadResult() const { return static_cast<PreloadResult>(m_preloadResult); }
143
144    virtual void didAddClient(ResourceClient*);
145    virtual void didRemoveClient(ResourceClient*) { }
146    virtual void allClientsRemoved();
147
148    unsigned count() const { return m_clients.size(); }
149
150    Status status() const { return static_cast<Status>(m_status); }
151    void setStatus(Status status) { m_status = status; }
152
153    size_t size() const { return encodedSize() + decodedSize() + overheadSize(); }
154    size_t encodedSize() const { return m_encodedSize; }
155    size_t decodedSize() const { return m_decodedSize; }
156    size_t overheadSize() const;
157
158    bool isLoaded() const { return !m_loading; } // FIXME. Method name is inaccurate. Loading might not have started yet.
159
160    bool isLoading() const { return m_loading; }
161    void setLoading(bool b) { m_loading = b; }
162    virtual bool stillNeedsLoad() const { return false; }
163
164    ResourceLoader* loader() const { return m_loader.get(); }
165
166    virtual bool isImage() const { return false; }
167    bool ignoreForRequestCount() const
168    {
169        return type() == MainResource
170            || type() == LinkPrefetch
171            || type() == LinkSubresource
172            || type() == Media
173            || type() == Raw
174            || type() == TextTrack;
175    }
176
177    // Computes the status of an object after loading.
178    // Updates the expire date on the cache entry file
179    void finish(double finishTime = 0.0);
180
181    // FIXME: Remove the stringless variant once all the callsites' error messages are updated.
182    bool passesAccessControlCheck(SecurityOrigin*);
183    bool passesAccessControlCheck(SecurityOrigin*, String& errorDescription);
184
185    void clearLoader();
186
187    SharedBuffer* resourceBuffer() const { return m_data.get(); }
188    void setResourceBuffer(PassRefPtr<SharedBuffer>);
189
190    virtual void willSendRequest(ResourceRequest&, const ResourceResponse&);
191
192    virtual void updateRequest(const ResourceRequest&) { }
193    virtual void responseReceived(const ResourceResponse&);
194    void setResponse(const ResourceResponse& response) { m_response = response; }
195    const ResourceResponse& response() const { return m_response; }
196
197    // Sets the serialized metadata retrieved from the platform's cache.
198    void setSerializedCachedMetadata(const char*, size_t);
199
200    // Caches the given metadata in association with this resource and suggests
201    // that the platform persist it. The dataTypeID is a pseudo-randomly chosen
202    // identifier that is used to distinguish data generated by the caller.
203    void setCachedMetadata(unsigned dataTypeID, const char*, size_t, MetadataCacheType = SendToPlatform);
204
205    // Reset existing metadata, to allow setting new data.
206    void clearCachedMetadata();
207
208    // Returns cached metadata of the given type associated with this resource.
209    CachedMetadata* cachedMetadata(unsigned dataTypeID) const;
210
211    bool hasOneHandle() const;
212    bool canDelete() const;
213
214    // List of acceptable MIME types separated by ",".
215    // A MIME type may contain a wildcard, e.g. "text/*".
216    AtomicString accept() const { return m_accept; }
217    void setAccept(const AtomicString& accept) { m_accept = accept; }
218
219    bool wasCanceled() const { return m_error.isCancellation(); }
220    bool errorOccurred() const { return m_status == LoadError || m_status == DecodeError; }
221    bool loadFailedOrCanceled() { return !m_error.isNull(); }
222
223    DataBufferingPolicy dataBufferingPolicy() const { return m_options.dataBufferingPolicy; }
224    void setDataBufferingPolicy(DataBufferingPolicy);
225
226    bool isUnusedPreload() const { return isPreloaded() && preloadResult() == PreloadNotReferenced; }
227    bool isPreloaded() const { return m_preloadCount; }
228    void increasePreloadCount() { ++m_preloadCount; }
229    void decreasePreloadCount() { ASSERT(m_preloadCount); --m_preloadCount; }
230
231    void registerHandle(ResourcePtrBase* h);
232    void unregisterHandle(ResourcePtrBase* h);
233
234    bool canReuseRedirectChain();
235    bool mustRevalidateDueToCacheHeaders();
236    bool canUseCacheValidator();
237    bool isCacheValidator() const { return m_resourceToRevalidate; }
238    Resource* resourceToRevalidate() const { return m_resourceToRevalidate; }
239    void setResourceToRevalidate(Resource*);
240    bool hasCacheControlNoStoreHeader();
241
242    bool isPurgeable() const;
243    bool wasPurged() const;
244    bool lock();
245
246    virtual void didSendData(unsigned long long /* bytesSent */, unsigned long long /* totalBytesToBeSent */) { }
247    virtual void didDownloadData(int) { }
248
249    double loadFinishTime() const { return m_loadFinishTime; }
250
251    virtual bool canReuse(const ResourceRequest&) const { return true; }
252
253    // Used by the MemoryCache to reduce the memory consumption of the entry.
254    void prune();
255
256    static const char* resourceTypeToString(Type, const FetchInitiatorInfo&);
257
258#ifdef ENABLE_RESOURCE_IS_DELETED_CHECK
259    void assertAlive() const { RELEASE_ASSERT(!m_deleted); }
260#else
261    void assertAlive() const { }
262#endif
263
264protected:
265    virtual void checkNotify();
266    virtual void finishOnePart();
267
268    // Normal resource pointers will silently switch what Resource* they reference when we
269    // successfully revalidated the resource. We need a way to guarantee that the Resource
270    // that received the 304 response survives long enough to switch everything over to the
271    // revalidatedresource. The normal mechanisms for keeping a Resource alive externally
272    // (ResourcePtrs and ResourceClients registering themselves) don't work in this case, so
273    // have a separate internal protector).
274    class InternalResourcePtr {
275    public:
276        explicit InternalResourcePtr(Resource* resource)
277            : m_resource(resource)
278        {
279            m_resource->incrementProtectorCount();
280        }
281
282        ~InternalResourcePtr()
283        {
284            m_resource->decrementProtectorCount();
285            m_resource->deleteIfPossible();
286        }
287    private:
288        Resource* m_resource;
289    };
290
291    void incrementProtectorCount() { m_protectorCount++; }
292    void decrementProtectorCount() { m_protectorCount--; }
293
294    void setEncodedSize(size_t);
295    void setDecodedSize(size_t);
296    void didAccessDecodedData();
297
298    virtual void switchClientsToRevalidatedResource();
299    void clearResourceToRevalidate();
300    void updateResponseAfterRevalidation(const ResourceResponse& validatingResponse);
301
302    void finishPendingClients();
303
304    HashCountedSet<ResourceClient*> m_clients;
305    HashCountedSet<ResourceClient*> m_clientsAwaitingCallback;
306
307    class ResourceCallback {
308    public:
309        static ResourceCallback* callbackHandler();
310        void schedule(Resource*);
311        void cancel(Resource*);
312        bool isScheduled(Resource*) const;
313    private:
314        ResourceCallback();
315        void timerFired(Timer<ResourceCallback>*);
316        Timer<ResourceCallback> m_callbackTimer;
317        HashSet<Resource*> m_resourcesWithPendingClients;
318    };
319
320    bool hasClient(ResourceClient* client) { return m_clients.contains(client) || m_clientsAwaitingCallback.contains(client); }
321
322    struct RedirectPair {
323    public:
324        explicit RedirectPair(const ResourceRequest& request, const ResourceResponse& redirectResponse)
325            : m_request(request)
326            , m_redirectResponse(redirectResponse)
327        {
328        }
329
330        ResourceRequest m_request;
331        ResourceResponse m_redirectResponse;
332    };
333    const Vector<RedirectPair>& redirectChain() const { return m_redirectChain; }
334
335    virtual bool isSafeToUnlock() const { return false; }
336    virtual void destroyDecodedDataIfPossible() { }
337
338    ResourceRequest m_resourceRequest;
339    AtomicString m_accept;
340    RefPtrWillBeMember<ResourceLoader> m_loader;
341    ResourceLoaderOptions m_options;
342
343    ResourceResponse m_response;
344    double m_responseTimestamp;
345
346    RefPtr<SharedBuffer> m_data;
347    Timer<Resource> m_cancelTimer;
348
349private:
350    bool addClientToSet(ResourceClient*);
351    void cancelTimerFired(Timer<Resource>*);
352
353    void revalidationSucceeded(const ResourceResponse&);
354    void revalidationFailed();
355
356    bool unlock();
357
358    bool hasRightHandleCountApartFromCache(unsigned targetCount) const;
359
360    void failBeforeStarting();
361
362    String m_fragmentIdentifierForRequest;
363
364    RefPtr<CachedMetadata> m_cachedMetadata;
365
366    ResourceError m_error;
367
368    double m_loadFinishTime;
369
370    unsigned long m_identifier;
371
372    size_t m_encodedSize;
373    size_t m_decodedSize;
374    unsigned m_handleCount;
375    unsigned m_preloadCount;
376    unsigned m_protectorCount;
377
378    unsigned m_preloadResult : 2; // PreloadResult
379    unsigned m_requestedFromNetworkingLayer : 1;
380
381    unsigned m_loading : 1;
382
383    unsigned m_switchingClientsToRevalidatedResource : 1;
384
385    unsigned m_type : 4; // Type
386    unsigned m_status : 3; // Status
387
388    unsigned m_wasPurged : 1;
389
390    unsigned m_needsSynchronousCacheHit : 1;
391
392#ifdef ENABLE_RESOURCE_IS_DELETED_CHECK
393    bool m_deleted;
394#endif
395
396    // 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
397    // using HTTP If-Modified-Since/If-None-Match headers. If the response is 304 all clients of this resource are moved
398    // to to be clients of m_resourceToRevalidate and the resource is deleted. If not, the field is zeroed and this
399    // resources becomes normal resource load.
400    RawPtrWillBeMember<Resource> m_resourceToRevalidate;
401
402    // If this field is non-null, the resource has a proxy for checking whether it is still up to date (see m_resourceToRevalidate).
403    RawPtrWillBeMember<Resource> m_proxyResource;
404
405    // These handles will need to be updated to point to the m_resourceToRevalidate in case we get 304 response.
406    HashSet<ResourcePtrBase*> m_handlesToRevalidate;
407
408    // Ordered list of all redirects followed while fetching this resource.
409    Vector<RedirectPair> m_redirectChain;
410
411    static unsigned s_instanceCount;
412};
413
414#if !LOG_DISABLED
415// Intended to be used in LOG statements.
416const char* ResourceTypeName(Resource::Type);
417#endif
418
419#define DEFINE_RESOURCE_TYPE_CASTS(typeName) \
420    DEFINE_TYPE_CASTS(typeName##Resource, Resource, resource, resource->type() == Resource::typeName, resource.type() == Resource::typeName); \
421    inline typeName##Resource* to##typeName##Resource(const ResourcePtr<Resource>& ptr) { return to##typeName##Resource(ptr.get()); }
422
423}
424
425#endif
426