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 URL;
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 setDefersLoading(ResourceLoader*, bool);
57    virtual void crossOriginRedirectReceived(ResourceLoader*, const URL& redirectURL);
58
59    virtual void servePendingRequests(ResourceLoadPriority minimumPriority = ResourceLoadPriorityVeryLow);
60    virtual void suspendPendingRequests();
61    virtual void resumePendingRequests();
62
63    bool isSerialLoadingEnabled() const { return m_isSerialLoadingEnabled; }
64    virtual void setSerialLoadingEnabled(bool b) { m_isSerialLoadingEnabled = b; }
65
66    class Suspender {
67    public:
68        explicit Suspender(ResourceLoadScheduler& scheduler) : m_scheduler(scheduler) { m_scheduler.suspendPendingRequests(); }
69        ~Suspender() { m_scheduler.resumePendingRequests(); }
70    private:
71        ResourceLoadScheduler& m_scheduler;
72    };
73
74protected:
75    ResourceLoadScheduler();
76    virtual ~ResourceLoadScheduler();
77
78    void notifyDidScheduleResourceRequest(ResourceLoader*);
79
80#if USE(QUICK_LOOK)
81    bool maybeLoadQuickLookResource(ResourceLoader&);
82#endif
83
84private:
85    void scheduleLoad(ResourceLoader*, ResourceLoadPriority);
86    void scheduleServePendingRequests();
87    void requestTimerFired(Timer<ResourceLoadScheduler>&);
88
89    bool isSuspendingPendingRequests() const { return !!m_suspendPendingRequestsCount; }
90
91    class HostInformation {
92        WTF_MAKE_NONCOPYABLE(HostInformation); WTF_MAKE_FAST_ALLOCATED;
93    public:
94        HostInformation(const String&, unsigned);
95        ~HostInformation();
96
97        const String& name() const { return m_name; }
98        void schedule(ResourceLoader*, ResourceLoadPriority = ResourceLoadPriorityVeryLow);
99        void addLoadInProgress(ResourceLoader*);
100        void remove(ResourceLoader*);
101        bool hasRequests() const;
102        bool limitRequests(ResourceLoadPriority) const;
103
104        typedef Deque<RefPtr<ResourceLoader>> RequestQueue;
105        RequestQueue& requestsPending(ResourceLoadPriority priority) { return m_requestsPending[priority]; }
106
107    private:
108        RequestQueue m_requestsPending[ResourceLoadPriorityHighest + 1];
109        typedef HashSet<RefPtr<ResourceLoader>> RequestMap;
110        RequestMap m_requestsLoading;
111        const String m_name;
112        const int m_maxRequestsInFlight;
113    };
114
115    enum CreateHostPolicy {
116        CreateIfNotFound,
117        FindOnly
118    };
119
120    HostInformation* hostForURL(const URL&, CreateHostPolicy = FindOnly);
121    void servePendingRequests(HostInformation*, ResourceLoadPriority);
122
123    typedef HashMap<String, HostInformation*, StringHash> HostMap;
124    HostMap m_hosts;
125    HostInformation* m_nonHTTPProtocolHost;
126
127    Timer<ResourceLoadScheduler> m_requestTimer;
128
129    unsigned m_suspendPendingRequestsCount;
130    bool m_isSerialLoadingEnabled;
131};
132
133ResourceLoadScheduler* resourceLoadScheduler();
134
135}
136
137#endif
138