[转]Use the IDA and LLDB explore WebCore C + + class inheritance

原文：http://www.phonesdevelopers.com/1781016/

The surgery class named PluginWidgetIOS use lldb can get:

(lldb) image lookup -r -s PluginWidgetIOS
7 symbols match the regular expression 'PluginWidgetIOS' in /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.1.sdk/System/Library/PrivateFrameworks/WebKit.framework/WebKit:
        Address: WebKit[0x0003a5a0] (WebKit.TEXT.text + 231680)
        Summary: WebKitPluginWidgetIOS::~PluginWidgetIOS()&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Address:&nbsp;WebKit[0x0003a5b0]&nbsp;(WebKit.__TEXT.__text&nbsp;+&nbsp;231696)&nbsp;&nbsp;</span> </li> <li class="alt" style="border-style: none none none solid; border-left- 3px; border-left-color: #6ce26c; list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;" data-iceapw="8" data-iceapc="1"> <span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;" data-iceapw="8">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Summary:&nbsp;WebKitPluginWidgetIOS::~PluginWidgetIOS()        Address: WebKit[0x0003a6f0] (WebKit.TEXT.text + 232016)
        Summary: WebKitPluginWidgetIOS::platformLayer()&nbsp;const&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Address:&nbsp;WebKit[0x0003a750]&nbsp;(WebKit.__TEXT.__text&nbsp;+&nbsp;232112)&nbsp;&nbsp;</span> </li> <li class="alt" style="border-style: none none none solid; border-left- 3px; border-left-color: #6ce26c; list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;" data-iceapw="9" data-iceapc="1"> <span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;" data-iceapw="9">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Summary:&nbsp;WebKitPluginWidgetIOS::willProvidePluginLayer() const        Address: WebKit[0x0003a7b0] (WebKit.TEXT.text + 232208)
        Summary: WebKitPluginWidgetIOS::attachPluginLayer()&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Address:&nbsp;WebKit[0x0003a810]&nbsp;(WebKit.__TEXT.__text&nbsp;+&nbsp;232304)&nbsp;&nbsp;</span> </li> <li class="alt" style="border-style: none none none solid; border-left- 3px; border-left-color: #6ce26c; list-style: decimal-leading-zero outside; color: inherit; line-height: 18px; margin: 0px !important; padding: 0px 3px 0px 10px !important;" data-iceapw="8" data-iceapc="1"> <span style="margin: 0px; padding: 0px; border: none; color: black; background-color: inherit;" data-iceapw="8">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Summary:&nbsp;WebKitPluginWidgetIOS::detachPluginLayer()        Address: WebKit[0x001335e0] (WebKit.DATA.data + 560)
        Summary: vtable for PluginWidgetIOS

Useful information:

Address: WebKit[0x001335e0] (WebKit.DATA.data + 560)
        Summary: vtable for PluginWidgetIOS

IDA Open WebCore static library, goto (shortcuts g) vtable address where 0x1335e0, you can see:

data:001335E0 ; `vtable for'PluginWidgetIOS
data:001335E0 ZTV15PluginWidgetIOS db    0          ; DATA XREF: nlsymbolptr:ZTV15PluginWidgetIOSptro
data:001335E1                 db    0
data:001335E2                 db    0
data:001335E3                 db    0
data:001335E4                 db    0
data:001335E5                 db    0
data:001335E6                 db    0
data:001335E7                 db    0
data:001335E8                 dd offset ZN15PluginWidgetIOSD1Ev ; PluginWidgetIOS::~PluginWidgetIOS()
data:001335EC                 dd offset ZN15PluginWidgetIOSD0Ev ; PluginWidgetIOS::~PluginWidgetIOS()
data:001335F0                 dd offset ZN7WebCore6Widget12setFrameRectERKNS7IntRectE ; WebCore::Widget::setFrameRect(WebCore::IntRect  const&)
data:001335F4                 dd offset ZN7WebCore6Widget5paintEPNS15GraphicsContextERKNS7IntRectE ; WebCore::Widget::paint(WebCore::GraphicsContext ,WebCore::IntRect  const&)
data:001335F8                 dd offset ZN12PluginWidget14invalidateRectERKN7WebCore7IntRectE ; PluginWidget::invalidateRect(WebCore::IntRect  const&)
data:001335FC                 dd offset ZN7WebCore6Widget8setFocusEb ; WebCore::Widget::setFocus(bool)
data:00133600                 dd offset ZN7WebCore6Widget4showEv ; WebCore::Widget::show(void)
data:00133604                 dd offset ZN7WebCore6Widget4hideEv ; WebCore::Widget::hide(void)
data:00133608                 dd offset ZN7WebCore6Widget16setParentVisibleEb ; WebCore::Widget::setParentVisible(bool)
data:0013360C                 dd offset ZNK7WebCore6Widget11isFrameViewEv ; WebCore::Widget::isFrameView(void)
data:00133610                 dd offset ZNK7WebCore6Widget12isPluginViewEv ; WebCore::Widget::isPluginView(void)
data:00133614                 dd offset ZNK7WebCore14PluginViewBase16isPluginViewBaseEv ; WebCore::PluginViewBase::isPluginViewBase(void)
data:00133618                 dd offset ZNK7WebCore6Widget11isScrollbarEv ; WebCore::Widget::isScrollbar(void)
data:0013361C                 dd offset ZN7WebCore6Widget9setParentEPNS_10ScrollViewE ; WebCore::Widget::setParent(WebCore::ScrollView )
data:00133620                 dd offset ZN7WebCore6Widget11handleEventEPNS5EventE ; WebCore::Widget::handleEvent(WebCore::Event *)
data:00133624                 dd offset ZN7WebCore6Widget12notifyWidgetENS18WidgetNotificationE ; WebCore::Widget::notifyWidget(WebCore::WidgetNotification)
data:00133628                 dd offset ZN7WebCore6Widget17frameRectsChangedEv ; WebCore::Widget::frameRectsChanged(void)
data:0013362C                 dd offset ZN7WebCore6Widget22widgetPositionsUpdatedEv ; WebCore::Widget::widgetPositionsUpdated(void)
data:00133630                 dd offset ZN7WebCore6Widget25transformsAffectFrameRectEv ; WebCore::Widget::transformsAffectFrameRect(void)
data:00133634                 dd offset ZNK7WebCore6Widget23convertToContainingViewERKNS7IntRectE ; WebCore::Widget::convertToContainingView(WebCore::IntRect  const&)
data:00133638                 dd offset ZNK7WebCore6Widget25convertFromContainingViewERKNS7IntRectE ; WebCore::Widget::convertFromContainingView(WebCore::IntRect  const&)
data:0013363C                 dd offset ZNK7WebCore6Widget23convertToContainingViewERKNS8IntPointE ; WebCore::Widget::convertToContainingView(WebCore::IntPoint  const&)
data:00133640                 dd offset ZNK7WebCore6Widget25convertFromContainingViewERKNS8IntPointE ; WebCore::Widget::convertFromContainingView(WebCore::IntPoint  const&)
data:00133644                 dd offset ZNK7WebCore6Widget13axObjectCacheEv ; WebCore::Widget::axObjectCache(void)
data:00133648                 dd offset ZNK15PluginWidgetIOS13platformLayerEv ; PluginWidgetIOS::platformLayer(void)
data:0013364C                 dd offset ZNK15PluginWidgetIOS22willProvidePluginLayerEv ; PluginWidgetIOS::willProvidePluginLayer(void)
data:00133650                 dd offset ZN15PluginWidgetIOS17attachPluginLayerEv ; PluginWidgetIOS::attachPluginLayer(void)
data:00133654                 dd offset ZN15PluginWidgetIOS17detachPluginLayerEv ; PluginWidgetIOS::detachPluginLayer(void)
data:00133658                 dd offset ZN7WebCore14PluginViewBase12scriptObjectEPN3JSC14JSGlobalObjectE ; WebCore::PluginViewBase::scriptObject(JSC::JSGlobalObject *)
data:0013365C                 dd offset ZN7WebCore14PluginViewBase27privateBrowsingStateChangedEb ; WebCore::PluginViewBase::privateBrowsingStateChanged(bool)
data:00133660                 dd offset ZN7WebCore14PluginViewBase12getFormValueERN3WTF6StringE ; WebCore::PluginViewBase::getFormValue(WTF::String &)
data:00133664                 dd offset ZN7WebCore14PluginViewBase6scrollENS15ScrollDirectionENS17ScrollGranularityE ; WebCore::PluginViewBase::scroll(WebCore::ScrollDirection,WebCore::ScrollGranularity)
data:00133668                 dd offset ZN7WebCore14PluginViewBase19horizontalScrollbarEv ; WebCore::PluginViewBase::horizontalScrollbar(void)
data:0013366C                 dd offset ZN7WebCore14PluginViewBase17verticalScrollbarEv ; WebCore::PluginViewBase::verticalScrollbar(void)
data:00133670                 dd offset ZN7WebCore14PluginViewBase16wantsWheelEventsEv ; WebCore::PluginViewBase::wantsWheelEvents(void)
__data:00133674                 align 10h

This is virtual function table PluginWidgetIOS. You can see from the comment after the semicolon function directly perform address point to the Widget, PluginWidget, PluginViewBase the function can the know PluginWidgetIOS is their direct or indirect subclass.

Reuse of the lldb image lookup these three classes, you can see the inheritance chain:

PluginWidgetIOS-> PluginViewBase-> PluginWidget-> Widget

The because the virtual list PluginWidget does not appear PluginViewBase the the Widget virtual table does not appear PluginWidget and PluginViewBase. Of course, these three classes in the open source can find inheritance.