iOS Safari阅读模式分析过程

太过爱你忘了你带给我的痛 2022-07-27 13:56 171阅读 0赞

本文为Safari阅读模式分析过程记录，没有做很好的整理。最终的输出见另一篇[iOS Safari阅读模式研究][iOS Safari]。

1. Break on evaluate

b JSC::evaluate(JSC::ExecState\*, JSC::ScopeChainNode\*, JSC::SourceCode const&, JSC::JSValue, JSC::JSValue\*)

dump the source content from JSC::SourceCode

![Center][]  
 Printing description of source.m\_provider.m\_ptr->m\_url:  
(WTF::String) m\_url = \{ length = 0, contents = '' \} \{  
  m\_impl = \{  
    m\_ptr = 0x0000000000000000 \{ length = 0, is8bit = 0, contents = '' \}  
  \}

Printing description of source.m\_provider.m\_ptr->m\_source:  
(WTF::String) m\_source = \{ length = 66370, contents = '/\*  
 \* Copyright © 2010 Apple Inc. All rights reserved.  
 \*/

……

2. Call Stack

![Center 1][]

3.  **(lldb)** **image list**

\[  0\] 396DF4E9-18D6-3C39-B1FB-E783D7F9B947 **0x00001000** /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.1.sdk/Applications/MobileSafari.app/MobileSafari

\-> JSEvaluateScript

0x70224( 0x702a5 ) ->

0x6fdc8( 0x6fe19 ) ->

0x6fd9a( 0x6fdb5 ) -> XREF:\-\[ReaderTestProcessor \_processReaderTestResult:tabDocument:\] & -\[ReaderContext isReaderAvailable\]

0x6eac5( 0x6eae5 ) -> \-\[ReaderContext isReaderAvailable\]

0xa3d84( 0xa3dd3)  -> XREF:\-\[TabDocument \_detectReaderAvailabilityOnWebThread\]

HandleRunSource

i. 查找起点

![Center 2][]

3483 ->  0xa3d15  \-\[TabDocument \_detectReaderAvailabilityOnWebThread\]

3490 ->  0xa3f56( 0xa404b)  -\[TabDocument \_detectReaderAvailabilityNow\]

ii. 谁发起了\_detectReaderAvailabilityNow

\-\[BrowserController stopFromAddressView:\]

\-\[TabDocument \_progressDidStall\]

\-\[TabDocument webView:didFinishLoadForFrame:\]

->   -\[TabDocument detectReaderAvailabilitySoon\]

![Center 3][]

3496-> 0xa4279  -\[TabDocument detectReaderAvailabilitySoon\]

3274->  0x9c16b ( 0x9c1ad) -\[TabDocument webView:didFinishLoadForFrame:\]

4. (FAILED)

**b -\[UIView setHidden:\]**

**(lldb)** **showParameters 3**  
$56 = 0x09a43aa0 <ReaderButtonView: 0x1a39ca50; baseClass = UIButton; frame = (276 2; 49 27); alpha = 0; opaque = NO; layer = <CALayer: 0x1a398610>>  
0x08d60840: "setHidden:"

b -\[UIView setFrame:\]

**(lldb)** **showParameters 3**  
$26 = 0x0a984730 <ReaderButtonView: 0x9af39d0; baseClass = UIButton; frame = (276 2; 49 27); alpha = 0; opaque = NO; layer = <CALayer: 0x9a6fb60>>  
0x07b37881: "setFrame:"

0x07b3788b: "addSubview:"

![Center 4][]

96 ->  0x6d38 ( 0x6f9d ):  -\[AddressView \_layoutReloadButtonForProgressViewFrame:forEditing:textField:showInactiveFieldWhileEditing:\]

257 ->  0x126a4 ( 0x1288a ): \-\[AddressView layoutReaderButton\]

3482 ->  0xa3927 ( 0xa3caf ): \-\[TabDocument \_didDetectReaderAvailability:\]

3485 ->  0xa3e3f ( 0xa3e6b ) : (MEM:didDetectReaderAvailability)

\-\[AddressViewaccessibility(SafeCategory) layoutReaderButton\]

6. (FAILED)

根据WebKit Objective-C Programming Guide, 获取JS数据需要先获取window对象:

**id win =  \[webview windowScriptObject\];**

前且所有的JS对象是使用 WebScriptObject包装起来的。

Summary: WebCore\`-\[WebScriptObject valueForKey:\]        Address: WebCore\[0x00d35b30\] (WebCore.\_\_TEXT.\_\_text + 13843984)

**(lldb)** **b WebCore\`-\[WebScriptObject valueForKey:\]**

Breakpoint 14: where = WebCore\`-\[WebScriptObject valueForKey:\], address = 0x03581700

TabDocument::

\- (void)\_detectReaderAvailabilityNow;     // IMP=0x000a3f56

\- (void)\_detectReaderAvailabilityOnWebThread;     // IMP=0x000a3d15

\- (void)\_didDetectReaderAvailability:(BOOL)arg1;     // IMP=0x000a3927

var ReaderArticleFinderJS = new ReaderArticleFinder(document);

![Center 5][]

**6fdc8(6fe24) -> 1b3ba(1b3d6) -> isReaderModeAvailable**

**9. break at ** JSObjectGetProperty

**(lldb)** **p/x \`\*(int\*)($ebp+16)\`**  
(int) $33 = 0x000debdf  
 **(lldb)** **mem read \`$33\`**  
0x000debdf: 69 73 52 65 61 64 65 72 4d 6f 64 65 41 76 61 69  isReaderModeAvai

0x000debef: 6c 61 62 6c 65 00 70 72 65 70 61 72 65 54 6f 54  lable.prepareToT

10. 还需要再获取对象

![Center 6][]

450 ->  0x1b774( 0x1b777 ) ->  return ReaderArticleFinderJS

1656 ->  0x5a70c ( 0x5a76e ) ->

2193 ->  0x70224 ( 0x70315 ) ->

2186 ->  0x6fdc8 ( 0x6fe19) ->

2185 ->0x6fd9a( 0x6fdb5 ) -> XREF:\-\[ReaderTestProcessor \_processReaderTestResult:tabDocument:\] & -\[ReaderContext isReaderAvailable\]

2125 ->0x6eac5( 0x6eae5 ) -> \-\[ReaderContext isReaderAvailable\]

3484 -> 0xa3d84( 0xa3dd3)  -> XREF:\-\[TabDocument \_detectReaderAvailabilityOnWebThread\]

11. click the "Reader" button

a.再次确认Reader Mode

![Center 7][]

2193-> 0x70224 ( 0x702a5)

2186-> 0x6fdc8( 0x6fe19)

2195-> 0x70372( 0x70387) WebThreadLock, call 6fdc8.

2146-> 0x6f3cd( 0x6f3f1) -> -\[ReaderContext createArticleFinder\]

978->  0x38445( 0x384f5) \[BrowserController setShowingReader:animated\]

122 ->  0x995c( 0x99bc) ->

bShowing = \[\[ BrowserController sharedBrowserController\]  isShowingReader\];

\[\[ BrowserController sharedBrowserController\]  setShowingReader:bShowing animated:YES\]

b. 显示出内容

i.加载html文件

![Center 8][]

\-> loadRequest ( Reader~ipad.html)

2132 -> 0x6ee1e ( 0x6ee96) \[ReaderContext loadReaderDocument\]

2118 -> 0x6e85b ( 0x6e959) \[ReaderContext createWebViewIfNeeded\]

3491-> 0xa4053 ( 0xa4097) \[TabDocument createBrowserReaderViewIfNeeded\]

979 -> 0x38549 ( 0x38610) \[BrowserController showReaderForTabDocument\]

978->  0x38445( 0x38526)  \[BrowserController setShowingReader:animated\]

122 -> 0x995c( 0x99bc)

bShowing = \[\[ BrowserController sharedBrowserController\]  isShowingReader\];

\[\[ BrowserController sharedBrowserController\]  setShowingReader:bShowing animated:YES\]

ii. 在WebView允许修改window object时，执行阅读模式处理脚本

![Center 9][]

2205 ->  0x705ce ( 0x7066f)

2127 ->  0x6eb17 ( 0x6eb62) -\[ReaderContext initReaderJSController:\]

1296 ->  0x4952c ( 0x49588) \[BrowserReaderView uiWebView:didClearWindowObject:forFrame\]

iii. 页面加载后会执行JS：

[iOS Safari]: http://blog.csdn.net/horkychen/article/details/50959771
[Center]: /images/20220727/2f8c7d84611f40589b786dbb718359b3.png
[Center 1]: /images/20220727/e58f269522eb41329ed55aa9bfabede8.png
[Center 2]: /images/20220727/54933264907b422589a5cb61d8085fe8.png
[Center 3]: /images/20220727/c9060e1e8fe349f4a5207af9fffb06eb.png
[Center 4]: /images/20220727/7d955880dc684c908ef10586747ff8e4.png
[Center 5]: /images/20220727/f7727cf20d084a6b962c290ff353e4b4.png
[Center 6]: /images/20220727/db10a336b61048f89b437f64cd9cc675.png
[Center 7]: /images/20220727/e1ffa8b9f093448b8b5709ef65dda4da.png
[Center 8]: /images/20220727/a196d3b99c674e0081b0fe5165bfd4b8.png
[Center 9]: /images/20220727/c73bee89440946cdbc1fd67b2af2b31a.png