iOS Safari阅读模式分析过程
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。
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
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
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
3483 ->
0xa3d15 -[TabDocument _detectReaderAvailabilityOnWebThread]
3490 ->
0xa3f56(
0xa404b) -[TabDocument _detectReaderAvailabilityNow]
ii. 谁发起了_detectReaderAvailabilityNow
-[BrowserController stopFromAddressView:]
-[TabDocument _progressDidStall]
-[TabDocument webView:didFinishLoadForFrame:]
-> -[TabDocument detectReaderAvailabilitySoon]
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:"
$56 = 0x09a43aa0 <ReaderButtonView: 0x1a39ca50; baseClass = UIButton; frame = (276 2; 49 27); alpha = 0; opaque = NO; layer = <CALayer: 0x1a398610>>
0x08d60840: "setHidden:"
5.
b -[UIView setFrame:]
(lldb)
showParameters 3$26 = 0x0a984730 <ReaderButtonView: 0x9af39d0; baseClass = UIButton; frame = (276 2; 49 27); alpha = 0; opaque = NO; layer = <CALayer: 0x9a6fb60>>
0x07b37881: "setFrame:"
0x07b3788b: "addSubview:"
96 ->
0x6d38 (
0x6f9d
): -[AddressView _layoutReloadButtonForProgressViewFrame:forEditing:textField:showInactiveFieldWhileEditing:]
257 ->
0x126a4 (
0x1288a
): -[AddressView layoutReaderButton]
3482 ->
0xa3927 (
0xa3caf
): -[TabDocument _didDetectReaderAvailability:]
3485 ->
0xa3e3f (
0xa3e6b
)
: (MEM:didDetectReaderAvailability)
-[AddressViewaccessibility(SafeCategory) layoutReaderButton]
6. (FAILED)
根据WebKit Objective-C Programming Guide, 获取JS数据需要先获取window对象:
id win = [webview windowScriptObject];
前且所有的JS对象是使用
WebScriptObject包装起来的。
Summary: WebCore`-[WebScriptObject valueForKey:] Address: WebCore[0x00d35b30] (WebCore.__TEXT.__text + 13843984)
(lldb)
b WebCore`-[WebScriptObject valueForKey:]
Breakpoint 14: where = WebCore`-[WebScriptObject valueForKey:], address = 0x03581700
7.
TabDocument::
- (void)_detectReaderAvailabilityNow; // IMP=0x000a3f56
- (void)_detectReaderAvailabilityOnWebThread; // IMP=0x000a3d15
- (void)_didDetectReaderAvailability:(BOOL)arg1; // IMP=0x000a3927
8.
var ReaderArticleFinderJS = new ReaderArticleFinder(document);
6fdc8(6fe24) -> 1b3ba(1b3d6) -> isReaderModeAvailable
9. break at
JSObjectGetProperty
(lldb)
p/x `*(int*)($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
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
0.
a.再次确认Reader Mode
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
-> 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
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：
<body class="preloading" onload="ReaderJS.loaded();" onscroll="articleHasScrolled();">