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, 2006, 2007, 2008 Apple Inc. All rights reserved.
5    Copyright (C) 2010 Google 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 ResourceLoadScheduler_h
24#define ResourceLoadScheduler_h
25
26#include "FrameLoaderTypes.h"
27#include "ResourceLoaderOptions.h"
28#include "ResourceLoadPriority.h"
29#include "Timer.h"
30#include <wtf/Deque.h>
31#include <wtf/HashMap.h>
32#include <wtf/HashSet.h>
33#include <wtf/Noncopyable.h>
34#include <wtf/text/StringHash.h>
35#include <wtf/text/WTFString.h>
36
37namespace WebCore {
38
39class CachedResource;
40class Frame;
41class KURL;
42class NetscapePlugInStreamLoader;
43class NetscapePlugInStreamLoaderClient;
44class ResourceLoader;
45class ResourceRequest;
46class SubresourceLoader;
47
48class ResourceLoadScheduler {
49    WTF_MAKE_NONCOPYABLE(ResourceLoadScheduler); WTF_MAKE_FAST_ALLOCATED;
50public:
51    friend ResourceLoadScheduler* resourceLoadScheduler();
52
53    virtual PassRefPtr<SubresourceLoader> scheduleSubresourceLoad(Frame*, CachedResource*, const ResourceRequest&, ResourceLoadPriority, const ResourceLoaderOptions&);
54    virtual PassRefPtr<NetscapePlugInStreamLoader> schedulePluginStreamLoad(Frame*, NetscapePlugInStreamLoaderClient*, const ResourceRequest&);
55    virtual void remove(ResourceLoader*);
56    virtual void crossOriginRedirectReceived(ResourceLoader*, const KURL& redirectURL);
57
58    virtual void servePendingRequests(ResourceLoadPriority minimumPriority = ResourceLoadPriorityVeryLow);
59    virtual void suspendPendingRequests();
60    virtual void resumePendingRequests();
61
62    bool isSerialLoadingEnabled() const { return m_isSerialLoadingEnabled; }
63    virtual void setSerialLoadingEnabled(bool b) { m_isSerialLoadingEnabled = b; }
64
65    class Suspender {
66    public:
67        explicit Suspender(ResourceLoadScheduler& scheduler) : m_scheduler(scheduler) { m_scheduler.suspendPendingRequests(); }
68        ~Suspender() { m_scheduler.resumePendingRequests(); }
69    private:
70        ResourceLoadScheduler& m_scheduler;
71    };
72
73protected:
74    ResourceLoadScheduler();
75    virtual ~ResourceLoadScheduler();
76
77    void notifyDidScheduleResourceRequest(ResourceLoader*);
78
79private:
80    void scheduleLoad(ResourceLoader*, ResourceLoadPriority);
81    void scheduleServePendingRequests();
82    void requestTimerFired(Timer<ResourceLoadScheduler>*);
83
84    bool isSuspendingPendingRequests() const { return !!m_suspendPendingRequestsCount; }
85
86    class HostInformation {
87        WTF_MAKE_NONCOPYABLE(HostInformation); WTF_MAKE_FAST_ALLOCATED;
88    public:
89        HostInformation(const String&, unsigned);
90        ~HostInformation();
91
92        const String& name() const { return m_name; }
93        void schedule(ResourceLoader*, ResourceLoadPriority = ResourceLoadPriorityVeryLow);
94        void addLoadInProgress(ResourceLoader*);
95        void remove(ResourceLoader*);
96        bool hasRequests() const;
97        bool limitRequests(ResourceLoadPriority) const;
98
99        typedef Deque<RefPtr<ResourceLoader> > RequestQueue;
100        RequestQueue& requestsPending(ResourceLoadPriority priority) { return m_requestsPending[priority]; }
101
102    private:
103        RequestQueue m_requestsPending[ResourceLoadPriorityHighest + 1];
104        typedef HashSet<RefPtr<ResourceLoader> > RequestMap;
105        RequestMap m_requestsLoading;
106        const String m_name;
107        const int m_maxRequestsInFlight;
108    };
109
110    enum CreateHostPolicy {
111        CreateIfNotFound,
112        FindOnly
113    };
114
115    HostInformation* hostForURL(const KURL&, CreateHostPolicy = FindOnly);
116    void servePendingRequests(HostInformation*, ResourceLoadPriority);
117
118    typedef HashMap<String, HostInformation*, StringHash> HostMap;
119    HostMap m_hosts;
120    HostInformation* m_nonHTTPProtocolHost;
121
122    Timer<ResourceLoadScheduler> m_requestTimer;
123
124    unsigned m_suspendPendingRequestsCount;
125    bool m_isSerialLoadingEnabled;
126};
127
128ResourceLoadScheduler* resourceLoadScheduler();
129
130}
131
132#endif
133