WebKit内核分析之FrameLoader

参考地址：http://blog.csdn.net/dlmu2001/article/details/6168545

FrameLoader类负责一个Frame的加载，在Frame的流程中起到非常重要的作用，同很多组件都有交互，本文将分析FrameLoader类的代码

1. 概述

顾名思义，FrameLoader是一个Frame的loader，它的作用就是为客户端提供一个下载一个Frame的一系列的接口。这里的客户指的是类的客户，比如Frame类，间接客户是上层应用，比如 qwebframe

从它的定义看，最容易想到的是一个load接口，用来将一个frame load下来。任何一个页面都需要一个mainframe，因此一个页面的下载一般就是从load 一个 mainframe开始

在 load frame的过程中，通过FrameLoaderClient接口将load过程的不同阶段告知客户

FrameLoader通过 setDocumentLoader相当于把load的工作委托给了 DocumentLoader类

FrameLoader同 DocumentLoader是has-a的关系。一般在load的时候创建 DocumentLoader。Frame调用DocumentLoader的startLoadingMainResource开始 load frame

类数据代码：

 1 class FrameLoader {
 2     WTF_MAKE_NONCOPYABLE(FrameLoader);
 3 private:
 4     Frame* m_frame;
 5     FrameLoaderClient* m_client;
 6
 7     mutable PolicyChecker m_policyChecker;
 8     mutable HistoryController m_history;
 9     mutable ResourceLoadNotifier m_notifer;
10     mutable SubframeLoader m_subframeLoader;
11     mutable FrameLoaderStateMachine m_stateMachine;
12
13     FrameState m_state;
14     FrameLoadType m_loadType;
15
16     // Document loaders for the three phases of frame loading. Note that while
17     // a new request is being loaded, the old document loader may still be referenced.
18     // E.g. while a new request is in the "policy" state, the old document loader may
19     // be consulted in particular as it makes sense to imply certain settings on the new loader.
20     RefPtr<DocumentLoader> m_documentLoader;
21     RefPtr<DocumentLoader> m_provisionalDocumentLoader;
22     RefPtr<DocumentLoader> m_policyDocumentLoader;
23
24     bool m_delegateIsHandlingProvisionalLoadError;
25
26     bool m_quickRedirectComing;
27     bool m_sentRedirectNotification;
28     bool m_inStopAllLoaders;
29
30     String m_outgoingReferrer;
31
32     bool m_isExecutingJavaScriptFormAction;
33
34     bool m_didCallImplicitClose;
35     bool m_wasUnloadEventEmitted;
36     bool m_pageDismissalEventBeingDispatched;
37     bool m_isComplete;
38     bool m_isLoadingMainResource;
39
40     RefPtr<SerializedScriptValue> m_pendingStateObject;
41
42     KURL m_workingURL;
43
44     OwnPtr<IconLoader> m_iconLoader;
45     bool m_mayLoadIconLater;
46
47     bool m_needsClear;
48
49     KURL m_submittedFormURL;
50
51     Timer<FrameLoader> m_checkTimer;
52     bool m_shouldCallCheckCompleted;
53     bool m_shouldCallCheckLoadComplete;
54
55     Frame* m_opener;
56     HashSet<Frame*> m_openedFrames;
57
58     bool m_didPerformFirstNavigation;
59     bool m_loadingFromCachedPage;
60     bool m_suppressOpenerInNewFrame;
61
62     SandboxFlags m_sandboxFlags;
63     SandboxFlags m_forcedSandboxFlags;
64
65     RefPtr<FrameNetworkingContext> m_networkingContext;
66
67     KURL m_previousUrl;
68 }

2. 类关系