The Tor Browser: python/lldbutils/README.txt@97036ab72558 (annotated)

python/lldbutils/README.txt@97036ab72558 (annotated)

python/lldbutils/README.txt

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 lldb debugging functionality for Gecko
 ======================================
 This directory contains a module, lldbutils, which is imported by the
 in-tree .lldbinit file.  The lldbutil modules define some lldb commands
 that are handy for debugging Gecko.
 If you want to add a new command or Python-implemented type summary, either add
 it to one of the existing broad area Python files (such as lldbutils/layout.py
 for layout-related commands) or create a new file if none of the existing files
 is appropriate.  If you add a new file, make sure you add it to __all__ in
 lldbutils/__init__.py.
 Supported commands
 ------------------
 Most commands below that can take a pointer to an object also support being
 called with a smart pointer like nsRefPtr or nsCOMPtr.
 * frametree EXPR, ft EXPR
   frametreelimited EXPR, ftl EXPR
   Shows information about a frame tree.  EXPR is an expression that
   is evaluated, and must be an nsIFrame*.  frametree displays the
   entire frame tree that contains the given frame.  frametreelimited
   displays a subtree of the frame tree rooted at the given frame.
   (lldb) p this
   (nsBlockFrame *) $4 = 0x000000011687fcb8
   (lldb) ftl this
   Block(div)(-1)@0x11687fcb8 {0,0,7380,690} [state=0002100000d04601] [content=0x11688c0c0] [sc=0x11687f990:-moz-scrolled-content]<
     line 0x116899130: count=1 state=inline,clean,prevmarginclean,not impacted,not wrapped,before:nobr,after:nobr[0x100] {60,0,0,690} vis-overflow=60,510,0,0 scr-overflow=60,510,0,0 <
       Text(0)""@0x1168990c0 {60,510,0,0} [state=0001000020404000] [content=0x11687ca10] [sc=0x11687fd88:-moz-non-element,parent=0x11687eb00] [run=0x115115e80][0,0,T]
     >
   >
   (lldb) ft this
   Viewport(-1)@0x116017430 [view=0x115efe190] {0,0,60,60} [state=000b063000002623] [sc=0x1160170f8:-moz-viewport]<
     HTMLScroll(html)(-1)@0x1160180d0 {0,0,0,0} [state=000b020000000403] [content=0x115e4d640] [sc=0x116017768:-moz-viewport-scroll]<
       ...
       Canvas(html)(-1)@0x116017e08 {0,0,60,60} vis-overflow=0,0,8340,2196 scr-overflow=0,0,8220,2196 [state=000b002000000601] [content=0x115e4d640] [sc=0x11687e0f8:-moz-scrolled-canvas]<
         Block(html)(-1)@0x11687e578 {0,0,60,2196} vis-overflow=0,0,8340,2196 scr-overflow=0,0,8220,2196 [state=000b100000d00601] [content=0x115e4d640] [sc=0x11687e4b8,parent=0x0]<
           line 0x11687ec48: count=1 state=block,clean,prevmarginclean,not impacted,not wrapped,before:nobr,after:nobr[0x48] bm=480 {480,480,0,1236} vis-overflow=360,426,7980,1410 scr-overflow=480,480,7740,1236 <
             Block(body)(1)@0x11687ebb0 {480,480,0,1236} vis-overflow=-120,-54,7980,1410 scr-overflow=0,0,7740,1236 [state=000b120000100601] [content=0x115ed8980] [sc=0x11687e990]<
               line 0x116899170: count=1 state=inline,clean,prevmarginclean,not impacted,not wrapped,before:nobr,after:nobr[0x0] {0,0,7740,1236} vis-overflow=-120,-54,7980,1410 scr-overflow=0,0,7740,1236 <
                 nsTextControlFrame@0x11687f068 {0,66,7740,1170} vis-overflow=-120,-120,7980,1410 scr-overflow=0,0,7740,1170 [state=0002000000004621] [content=0x115ca2c50] [sc=0x11687ea40]<
                   HTMLScroll(div)(-1)@0x11687f6b0 {180,240,7380,690} [state=0002000000084409] [content=0x11688c0c0] [sc=0x11687eb00]<
                     Block(div)(-1)@0x11687fcb8 {0,0,7380,690} [state=0002100000d04601] [content=0x11688c0c0] [sc=0x11687f990:-moz-scrolled-content]<
                       line 0x116899130: count=1 state=inline,clean,prevmarginclean,not impacted,not wrapped,before:nobr,after:nobr[0x100] {60,0,0,690} vis-overflow=60,510,0,0 scr-overflow=60,510,0,0 <
                         Text(0)""@0x1168990c0 {60,510,0,0} [state=0001000020404000] [content=0x11687ca10] [sc=0x11687fd88:-moz-non-element,parent=0x11687eb00] [run=0x115115e80][0,0,T]
  ...
 * js
   Dumps the current JS stack.
   (lldb) js
 anonymous(aForce = false) ["chrome://browser/content/browser.js":13414]
       this = [object Object]
 updateAppearance() ["chrome://browser/content/browser.js":13326]
       this = [object Object]
 handleEvent(aEvent = [object Event]) ["chrome://browser/content/tabbrowser.xml":3811]
       this = [object XULElement]
 * prefcnt EXPR
   Shows the refcount of a given object.  EXPR is an expression that is
   evaluated, and can be either a pointer to or an actual refcounted
   object.  The object can be a standard nsISupports-like refcounted
   object, a cycle-collected object or a mozilla::RefCounted<T> object.
   (lldb) p this
   (nsHTMLDocument *) $1 = 0x0000000116e9d800
   (lldb) prefcnt this
 
   (lldb) p mDocumentURI
   (nsCOMPtr<nsIURI>) $3 = {
     mRawPtr = 0x0000000117163e50
   }
   (lldb) prefcnt mDocumentURI
 
 * pstate EXPR
   Shows the frame state bits (using their symbolic names) of a given frame.
   EXPR is an expression that is evaluated, and must be an nsIFrame*.
   (lldb) p this
   (nsTextFrame *) $1 = 0x000000011f470b10
   (lldb) p/x mState
   (nsFrameState) $2 = 0x0000004080604000
   (lldb) pstate this
   TEXT_HAS_NONCOLLAPSED_CHARACTERS | TEXT_END_OF_LINE | TEXT_START_OF_LINE | NS_FRAME_PAINTED_THEBES | NS_FRAME_INDEPENDENT_SELECTION
 * ptag EXPR
   Shows the DOM tag name of a node.  EXPR is an expression that is
   evaluated, and can be either an nsINode pointer or a concrete DOM
   object.
   (lldb) p this
   (nsHTMLDocument *) $0 = 0x0000000116e9d800
   (lldb) ptag this
   (PermanentAtomImpl *) $1 = 0x0000000110133ac0 u"#document"
   (lldb) p this->GetRootElement()
   (mozilla::dom::HTMLSharedElement *) $2 = 0x0000000118429780
   (lldb) ptag $2
   (PermanentAtomImpl *) $3 = 0x0000000110123b80 u"html"
 Supported type summaries and synthetic children
 -----------------------------------------------
 In lldb terminology, type summaries are rules for how to display a value
 when using the "expression" command (or its familiar-to-gdb-users "p" alias),
 and synthetic children are fake member variables or array elements also
 added by custom rules.
 For objects that do have synthetic children defined for them, like nsTArray,
 the "expr -R -- EXPR" command can be used to show its actual member variables.
 * nsAString, nsACString,
   nsFixedString, nsFixedCString,
   nsAutoString, nsAutoCString
   Strings have a type summary that shows the actual string.
   (lldb) frame info
   frame #0: 0x000000010400cfea XUL`nsCSSParser::ParseProperty(this=0x00007fff5fbf5248, aPropID=eCSSProperty_margin_top, aPropValue=0x00007fff5fbf53f8, aSheetURI=0x0000000115ae8c00, aBaseURI=0x0000000115ae8c00, aSheetPrincipal=0x000000010ff9e040, aDeclaration=0x00000001826fd580, aChanged=0x00007fff5fbf5247, aIsImportant=false, aIsSVGMode=false) + 74 at nsCSSParser.cpp:12851
   (lldb) p aPropValue
   (const nsAString_internal) $16 = u"-25px"
   (lldb) p this
   (nsHTMLDocument *) $18 = 0x0000000115b56000
   (lldb) p mContentType
   (nsCString) $19 = {
     nsACString_internal = "text/html"
   }
 * nscolor
   nscolors (32-bit RGBA colors) have a type summary that shows the color as
   one of the CSS 2.1 color keywords, a six digit hex color, an rgba() color,
   or the "transparent" keyword.
   (lldb) p this
   (nsTextFrame *) $0 = 0x00000001168245e0
   (lldb) p *this->StyleColor()
   (const nsStyleColor) $1 = {
     mColor = lime
   }
   (lldb) expr -R -- *this->StyleColor()
   (const nsStyleColor) $2 = {
     mColor = 4278255360
   }
 * nsIAtom
   Atoms have a type summary that shows the string value inside the atom.
   (lldb) frame info
   frame #0: 0x00000001028b8c49 XUL`mozilla::dom::Element::GetBoolAttr(this=0x0000000115ca1c50, aAttr=0x000000011012a640) const + 25 at Element.h:907
   (lldb) p aAttr
   (PermanentAtomImpl *) $1 = 0x000000011012a640 u"readonly"
 * nsTArray and friends
   nsTArrays and their auto and fallible varieties have synthetic children
   for their elements.  This means when displaying them with "expr" (or "p"),
   they will be shown like regular arrays, rather than showing the mHdr and
   other fields.
   (lldb) frame info
   frame #0: 0x00000001043eb8a8 XUL`SVGTextFrame::DoGlyphPositioning(this=0x000000012f3f8778) + 248 at SVGTextFrame.cpp:4940
   (lldb) p charPositions
   (nsTArray<nsPoint>) $5 = {
     [0] = {
       mozilla::gfx::BasePoint<int, nsPoint> = {
         x = 0
         y = 816
       }
     }
     [1] = {
       mozilla::gfx::BasePoint<int, nsPoint> = {
         x = 426
         y = 816
       }
     }
     [2] = {
       mozilla::gfx::BasePoint<int, nsPoint> = {
         x = 906
         y = 816
       }
     }
   }
   (lldb) expr -R -- charPositions
   (nsTArray<nsPoint>) $4 = {
     nsTArray_Impl<nsPoint, nsTArrayInfallibleAllocator> = {
       nsTArray_base<nsTArrayInfallibleAllocator, nsTArray_CopyWithMemutils> = {
         mHdr = 0x000000012f3f1b80
       }
     }
   }
 * nsTextNode, nsTextFragment
   Text nodes have a type summary that shows the nsTextFragment in the
   nsTextNode, which itself has a type summary that shows the text
   content.
   (lldb) p this
   (nsTextFrame *) $14 = 0x000000011811bb10
   (lldb) p mContent
   (nsTextNode *) $15 = 0x0000000118130110 "Search or enter address"

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python/lldbutils/README.txt@97036ab72558 (annotated)

python/lldbutils/README.txt