The Tor Browser: dom/base/nsWindowMemoryReporter.cpp@6474c204b198 (annotated)

dom/base/nsWindowMemoryReporter.cpp@6474c204b198 (annotated)

dom/base/nsWindowMemoryReporter.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "amIAddonManager.h"
 #include "nsWindowMemoryReporter.h"
 #include "nsGlobalWindow.h"
 #include "nsIDocument.h"
 #include "nsIDOMWindowCollection.h"
 #include "nsIEffectiveTLDService.h"
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Services.h"
 #include "mozilla/StaticPtr.h"
 #include "nsNetCID.h"
 #include "nsPrintfCString.h"
 #include "XPCJSMemoryReporter.h"
 #include "js/MemoryMetrics.h"
 #include "nsServiceManagerUtils.h"
 using namespace mozilla;
 StaticRefPtr<nsWindowMemoryReporter> sWindowReporter;
 /**
  * Don't trigger a ghost window check when a DOM window is detached if we've
  * run it this recently.
  */
 const int32_t kTimeBetweenChecks = 45; /* seconds */
 nsWindowMemoryReporter::nsWindowMemoryReporter()
   : mLastCheckForGhostWindows(TimeStamp::NowLoRes()),
     mCycleCollectorIsRunning(false),
     mCheckTimerWaitingForCCEnd(false)
 {
 }
 nsWindowMemoryReporter::~nsWindowMemoryReporter()
 {
   KillCheckTimer();
 }
 NS_IMPL_ISUPPORTS(nsWindowMemoryReporter, nsIMemoryReporter, nsIObserver,
                   nsISupportsWeakReference)
 static nsresult
 AddNonJSSizeOfWindowAndItsDescendents(nsGlobalWindow* aWindow,
                                       nsTabSizes* aSizes)
 {
   // Measure the window.
   nsWindowSizes windowSizes(moz_malloc_size_of);
   aWindow->AddSizeOfIncludingThis(&windowSizes);
   windowSizes.addToTabSizes(aSizes);
   // Measure the inner window, if there is one.
   nsWindowSizes innerWindowSizes(moz_malloc_size_of);
   nsGlobalWindow* inner = aWindow->GetCurrentInnerWindowInternal();
   if (inner) {
     inner->AddSizeOfIncludingThis(&innerWindowSizes);
     innerWindowSizes.addToTabSizes(aSizes);
   }
   nsCOMPtr<nsIDOMWindowCollection> frames;
   nsresult rv = aWindow->GetFrames(getter_AddRefs(frames));
   NS_ENSURE_SUCCESS(rv, rv);
   uint32_t length;
   rv = frames->GetLength(&length);
   NS_ENSURE_SUCCESS(rv, rv);
   // Measure this window's descendents.
   for (uint32_t i = 0; i < length; i++) {
       nsCOMPtr<nsIDOMWindow> child;
       rv = frames->Item(i, getter_AddRefs(child));
       NS_ENSURE_SUCCESS(rv, rv);
       NS_ENSURE_STATE(child);
       nsGlobalWindow* childWin =
         static_cast<nsGlobalWindow*>(static_cast<nsIDOMWindow *>(child.get()));
       rv = AddNonJSSizeOfWindowAndItsDescendents(childWin, aSizes);
       NS_ENSURE_SUCCESS(rv, rv);
   }
   return NS_OK;
 }
 static nsresult
 NonJSSizeOfTab(nsPIDOMWindow* aWindow, size_t* aDomSize, size_t* aStyleSize, size_t* aOtherSize)
 {
   nsGlobalWindow* window = static_cast<nsGlobalWindow*>(aWindow);
   nsTabSizes sizes;
   nsresult rv = AddNonJSSizeOfWindowAndItsDescendents(window, &sizes);
   NS_ENSURE_SUCCESS(rv, rv);
   *aDomSize   = sizes.mDom;
   *aStyleSize = sizes.mStyle;
   *aOtherSize = sizes.mOther;
   return NS_OK;
 }
 /* static */ void
 nsWindowMemoryReporter::Init()
 {
   MOZ_ASSERT(!sWindowReporter);
   sWindowReporter = new nsWindowMemoryReporter();
   ClearOnShutdown(&sWindowReporter);
   RegisterStrongMemoryReporter(sWindowReporter);
   RegisterNonJSSizeOfTab(NonJSSizeOfTab);
   nsCOMPtr<nsIObserverService> os = services::GetObserverService();
   if (os) {
     // DOM_WINDOW_DESTROYED_TOPIC announces what we call window "detachment",
     // when a window's docshell is set to nullptr.
     os->AddObserver(sWindowReporter, DOM_WINDOW_DESTROYED_TOPIC,
                     /* weakRef = */ true);
     os->AddObserver(sWindowReporter, "after-minimize-memory-usage",
                     /* weakRef = */ true);
     os->AddObserver(sWindowReporter, "cycle-collector-begin",
                     /* weakRef = */ true);
     os->AddObserver(sWindowReporter, "cycle-collector-end",
                     /* weakRef = */ true);
   }
   RegisterStrongMemoryReporter(new GhostWindowsReporter());
   RegisterGhostWindowsDistinguishedAmount(GhostWindowsReporter::DistinguishedAmount);
 }
 static already_AddRefed<nsIURI>
 GetWindowURI(nsIDOMWindow *aWindow)
 {
   nsCOMPtr<nsPIDOMWindow> pWindow = do_QueryInterface(aWindow);
   NS_ENSURE_TRUE(pWindow, nullptr);
   nsCOMPtr<nsIDocument> doc = pWindow->GetExtantDoc();
   nsCOMPtr<nsIURI> uri;
   if (doc) {
     uri = doc->GetDocumentURI();
   }
   if (!uri) {
     nsCOMPtr<nsIScriptObjectPrincipal> scriptObjPrincipal =
       do_QueryInterface(aWindow);
     NS_ENSURE_TRUE(scriptObjPrincipal, nullptr);
     // GetPrincipal() will print a warning if the window does not have an outer
     // window, so check here for an outer window first.  This code is
     // functionally correct if we leave out the GetOuterWindow() check, but we
     // end up printing a lot of warnings during debug mochitests.
     if (pWindow->GetOuterWindow()) {
       nsIPrincipal* principal = scriptObjPrincipal->GetPrincipal();
       if (principal) {
         principal->GetURI(getter_AddRefs(uri));
       }
     }
   }
   return uri.forget();
 }
 static void
 AppendWindowURI(nsGlobalWindow *aWindow, nsACString& aStr)
 {
   nsCOMPtr<nsIURI> uri = GetWindowURI(aWindow);
   if (uri) {
     nsCString spec;
     uri->GetSpec(spec);
     // A hack: replace forward slashes with '\\' so they aren't
     // treated as path separators.  Users of the reporters
     // (such as about:memory) have to undo this change.
     spec.ReplaceChar('/', '\\');
     aStr += spec;
   } else {
     // If we're unable to find a URI, we're dealing with a chrome window with
     // no document in it (or somesuch), so we call this a "system window".
     aStr += NS_LITERAL_CSTRING("[system]");
   }
 }
 MOZ_DEFINE_MALLOC_SIZE_OF(WindowsMallocSizeOf)
 // The key is the window ID.
 typedef nsDataHashtable<nsUint64HashKey, nsCString> WindowPaths;
 static nsresult
 ReportAmount(const nsCString& aBasePath, const char* aPathTail,
              size_t aAmount, const nsCString& aDescription,
              uint32_t aKind, uint32_t aUnits,
              nsIMemoryReporterCallback* aCb,
              nsISupports* aClosure)
 {
   if (aAmount == 0) {
     return NS_OK;
   }
   nsAutoCString path(aBasePath);
   path += aPathTail;
   return aCb->Callback(EmptyCString(), path, aKind, aUnits,
                        aAmount, aDescription, aClosure);
 }
 static nsresult
 ReportSize(const nsCString& aBasePath, const char* aPathTail,
            size_t aAmount, const nsCString& aDescription,
            nsIMemoryReporterCallback* aCb,
            nsISupports* aClosure)
 {
   return ReportAmount(aBasePath, aPathTail, aAmount, aDescription,
                       nsIMemoryReporter::KIND_HEAP,
                       nsIMemoryReporter::UNITS_BYTES, aCb, aClosure);
 }
 static nsresult
 ReportCount(const nsCString& aBasePath, const char* aPathTail,
             size_t aAmount, const nsCString& aDescription,
             nsIMemoryReporterCallback* aCb,
             nsISupports* aClosure)
 {
   return ReportAmount(aBasePath, aPathTail, aAmount, aDescription,
                       nsIMemoryReporter::KIND_OTHER,
                       nsIMemoryReporter::UNITS_COUNT, aCb, aClosure);
 }
 static nsresult
 CollectWindowReports(nsGlobalWindow *aWindow,
                      amIAddonManager *addonManager,
                      nsWindowSizes *aWindowTotalSizes,
                      nsTHashtable<nsUint64HashKey> *aGhostWindowIDs,
                      WindowPaths *aWindowPaths,
                      WindowPaths *aTopWindowPaths,
                      nsIMemoryReporterCallback *aCb,
                      nsISupports *aClosure)
 {
   nsAutoCString windowPath("explicit/");
   // Avoid calling aWindow->GetTop() if there's no outer window.  It will work
   // just fine, but will spew a lot of warnings.
   nsGlobalWindow *top = nullptr;
   nsCOMPtr<nsIURI> location;
   if (aWindow->GetOuterWindow()) {
     // Our window should have a null top iff it has a null docshell.
     MOZ_ASSERT(!!aWindow->GetTop() == !!aWindow->GetDocShell());
     top = aWindow->GetTop();
     if (top) {
       location = GetWindowURI(top);
     }
   }
   if (!location) {
     location = GetWindowURI(aWindow);
   }
   if (addonManager && location) {
     bool ok;
     nsAutoCString id;
     if (NS_SUCCEEDED(addonManager->MapURIToAddonID(location, id, &ok)) && ok) {
       windowPath += NS_LITERAL_CSTRING("add-ons/") + id +
                     NS_LITERAL_CSTRING("/");
     }
   }
   windowPath += NS_LITERAL_CSTRING("window-objects/");
   if (top) {
     windowPath += NS_LITERAL_CSTRING("top(");
     AppendWindowURI(top, windowPath);
     windowPath += NS_LITERAL_CSTRING(", id=");
     windowPath.AppendInt(top->WindowID());
     windowPath += NS_LITERAL_CSTRING(")");
     aTopWindowPaths->Put(aWindow->WindowID(), windowPath);
     windowPath += aWindow->IsFrozen() ? NS_LITERAL_CSTRING("/cached/")
                                       : NS_LITERAL_CSTRING("/active/");
   } else {
     if (aGhostWindowIDs->Contains(aWindow->WindowID())) {
       windowPath += NS_LITERAL_CSTRING("top(none)/ghost/");
     } else {
       windowPath += NS_LITERAL_CSTRING("top(none)/detached/");
     }
   }
   windowPath += NS_LITERAL_CSTRING("window(");
   AppendWindowURI(aWindow, windowPath);
   windowPath += NS_LITERAL_CSTRING(")");
   // Use |windowPath|, but replace "explicit/" with "event-counts/".
   nsCString censusWindowPath(windowPath);
   censusWindowPath.Replace(0, strlen("explicit"), "event-counts");
   // Remember the path for later.
   aWindowPaths->Put(aWindow->WindowID(), windowPath);
 #define REPORT_SIZE(_pathTail, _amount, _desc)                                \
   do {                                                                        \
     nsresult rv = ReportSize(windowPath, _pathTail, _amount,                  \
                              NS_LITERAL_CSTRING(_desc), aCb, aClosure);       \
     NS_ENSURE_SUCCESS(rv, rv);                                                \
   } while (0)
 #define REPORT_COUNT(_pathTail, _amount, _desc)                               \
   do {                                                                        \
     nsresult rv = ReportCount(censusWindowPath, _pathTail, _amount,           \
                               NS_LITERAL_CSTRING(_desc), aCb, aClosure);      \
     NS_ENSURE_SUCCESS(rv, rv);                                                \
   } while (0)
   nsWindowSizes windowSizes(WindowsMallocSizeOf);
   aWindow->AddSizeOfIncludingThis(&windowSizes);
   REPORT_SIZE("/dom/element-nodes", windowSizes.mDOMElementNodesSize,
               "Memory used by the element nodes in a window's DOM.");
   aWindowTotalSizes->mDOMElementNodesSize += windowSizes.mDOMElementNodesSize;
   REPORT_SIZE("/dom/text-nodes", windowSizes.mDOMTextNodesSize,
               "Memory used by the text nodes in a window's DOM.");
   aWindowTotalSizes->mDOMTextNodesSize += windowSizes.mDOMTextNodesSize;
   REPORT_SIZE("/dom/cdata-nodes", windowSizes.mDOMCDATANodesSize,
               "Memory used by the CDATA nodes in a window's DOM.");
   aWindowTotalSizes->mDOMCDATANodesSize += windowSizes.mDOMCDATANodesSize;
   REPORT_SIZE("/dom/comment-nodes", windowSizes.mDOMCommentNodesSize,
               "Memory used by the comment nodes in a window's DOM.");
   aWindowTotalSizes->mDOMCommentNodesSize += windowSizes.mDOMCommentNodesSize;
   REPORT_SIZE("/dom/event-targets", windowSizes.mDOMEventTargetsSize,
               "Memory used by the event targets table in a window's DOM, and "
               "the objects it points to, which include XHRs.");
   aWindowTotalSizes->mDOMEventTargetsSize += windowSizes.mDOMEventTargetsSize;
   REPORT_COUNT("/dom/event-targets", windowSizes.mDOMEventTargetsCount,
                "Number of non-node event targets in the event targets table "
                "in a window's DOM, such as XHRs.");
   aWindowTotalSizes->mDOMEventTargetsCount +=
     windowSizes.mDOMEventTargetsCount;
   REPORT_COUNT("/dom/event-listeners", windowSizes.mDOMEventListenersCount,
                "Number of event listeners in a window, including event "
                "listeners on nodes and other event targets.");
   aWindowTotalSizes->mDOMEventListenersCount +=
     windowSizes.mDOMEventListenersCount;
   REPORT_SIZE("/dom/other", windowSizes.mDOMOtherSize,
               "Memory used by a window's DOM that isn't measured by the "
               "other 'dom/' numbers.");
   aWindowTotalSizes->mDOMOtherSize += windowSizes.mDOMOtherSize;
   REPORT_SIZE("/property-tables",
               windowSizes.mPropertyTablesSize,
               "Memory used for the property tables within a window.");
   aWindowTotalSizes->mPropertyTablesSize += windowSizes.mPropertyTablesSize;
   REPORT_SIZE("/style-sheets", windowSizes.mStyleSheetsSize,
               "Memory used by style sheets within a window.");
   aWindowTotalSizes->mStyleSheetsSize += windowSizes.mStyleSheetsSize;
   REPORT_SIZE("/layout/pres-shell", windowSizes.mLayoutPresShellSize,
               "Memory used by layout's PresShell, along with any structures "
               "allocated in its arena and not measured elsewhere, "
               "within a window.");
   aWindowTotalSizes->mLayoutPresShellSize += windowSizes.mLayoutPresShellSize;
   REPORT_SIZE("/layout/line-boxes", windowSizes.mArenaStats.mLineBoxes,
               "Memory used by line boxes within a window.");
   aWindowTotalSizes->mArenaStats.mLineBoxes
     += windowSizes.mArenaStats.mLineBoxes;
   REPORT_SIZE("/layout/rule-nodes", windowSizes.mArenaStats.mRuleNodes,
               "Memory used by CSS rule nodes within a window.");
   aWindowTotalSizes->mArenaStats.mRuleNodes
     += windowSizes.mArenaStats.mRuleNodes;
   REPORT_SIZE("/layout/style-contexts", windowSizes.mArenaStats.mStyleContexts,
               "Memory used by style contexts within a window.");
   aWindowTotalSizes->mArenaStats.mStyleContexts
     += windowSizes.mArenaStats.mStyleContexts;
   REPORT_SIZE("/layout/style-sets", windowSizes.mLayoutStyleSetsSize,
               "Memory used by style sets within a window.");
   aWindowTotalSizes->mLayoutStyleSetsSize += windowSizes.mLayoutStyleSetsSize;
   REPORT_SIZE("/layout/text-runs", windowSizes.mLayoutTextRunsSize,
               "Memory used for text-runs (glyph layout) in the PresShell's "
               "frame tree, within a window.");
   aWindowTotalSizes->mLayoutTextRunsSize += windowSizes.mLayoutTextRunsSize;
   REPORT_SIZE("/layout/pres-contexts", windowSizes.mLayoutPresContextSize,
          "Memory used for the PresContext in the PresShell's frame "
          "within a window.");
   aWindowTotalSizes->mLayoutPresContextSize +=
     windowSizes.mLayoutPresContextSize;
   // There are many different kinds of frames, but it is very likely
   // that only a few matter.  Implement a cutoff so we don't bloat
   // about:memory with many uninteresting entries.
   const size_t FRAME_SUNDRIES_THRESHOLD =
     js::MemoryReportingSundriesThreshold();
   size_t frameSundriesSize = 0;
 #define FRAME_ID(classname)                                             \
   {                                                                     \
     size_t frameSize                                                    \
       = windowSizes.mArenaStats.FRAME_ID_STAT_FIELD(classname);         \
     if (frameSize < FRAME_SUNDRIES_THRESHOLD) {                         \
       frameSundriesSize += frameSize;                                   \
     } else {                                                            \
       REPORT_SIZE("/layout/frames/" # classname, frameSize,             \
                   "Memory used by frames of "                           \
                   "type " #classname " within a window.");              \
     }                                                                   \
     aWindowTotalSizes->mArenaStats.FRAME_ID_STAT_FIELD(classname)       \
       += frameSize;                                                     \
   }
 #include "nsFrameIdList.h"
 #undef FRAME_ID
   if (frameSundriesSize > 0) {
     REPORT_SIZE("/layout/frames/sundries", frameSundriesSize,
                 "The sum of all memory used by frames which were too small "
                 "to be shown individually.");
   }
 #undef REPORT_SIZE
 #undef REPORT_COUNT
   return NS_OK;
 }
 typedef nsTArray< nsRefPtr<nsGlobalWindow> > WindowArray;
 static
 PLDHashOperator
 GetWindows(const uint64_t& aId, nsGlobalWindow*& aWindow, void* aClosure)
 {
   ((WindowArray *)aClosure)->AppendElement(aWindow);
   return PL_DHASH_NEXT;
 }
 struct ReportGhostWindowsEnumeratorData
 {
   nsIMemoryReporterCallback* callback;
   nsISupports* closure;
   nsresult rv;
 };
 static PLDHashOperator
 ReportGhostWindowsEnumerator(nsUint64HashKey* aIDHashKey, void* aClosure)
 {
   ReportGhostWindowsEnumeratorData *data =
     static_cast<ReportGhostWindowsEnumeratorData*>(aClosure);
   nsGlobalWindow::WindowByIdTable* windowsById =
     nsGlobalWindow::GetWindowsTable();
   if (!windowsById) {
     NS_WARNING("Couldn't get window-by-id hashtable?");
     return PL_DHASH_NEXT;
   }
   nsGlobalWindow* window = windowsById->Get(aIDHashKey->GetKey());
   if (!window) {
     NS_WARNING("Could not look up window?");
     return PL_DHASH_NEXT;
   }
   nsAutoCString path;
   path.AppendLiteral("ghost-windows/");
   AppendWindowURI(window, path);
   nsresult rv = data->callback->Callback(
     /* process = */ EmptyCString(),
     path,
     nsIMemoryReporter::KIND_OTHER,
     nsIMemoryReporter::UNITS_COUNT,
     /* amount = */ 1,
     /* description = */ NS_LITERAL_CSTRING("A ghost window."),
     data->closure);
   if (NS_FAILED(rv) && NS_SUCCEEDED(data->rv)) {
     data->rv = rv;
   }
   return PL_DHASH_NEXT;
 }
 NS_IMETHODIMP
 nsWindowMemoryReporter::CollectReports(nsIMemoryReporterCallback* aCb,
                                        nsISupports* aClosure)
 {
   nsGlobalWindow::WindowByIdTable* windowsById =
     nsGlobalWindow::GetWindowsTable();
   NS_ENSURE_TRUE(windowsById, NS_OK);
   // Hold on to every window in memory so that window objects can't be
   // destroyed while we're calling the memory reporter callback.
   WindowArray windows;
   windowsById->Enumerate(GetWindows, &windows);
   // Get the IDs of all the "ghost" windows, and call aCb->Callback() for each
   // one.
   nsTHashtable<nsUint64HashKey> ghostWindows;
   CheckForGhostWindows(&ghostWindows);
   ReportGhostWindowsEnumeratorData reportGhostWindowsEnumData =
     { aCb, aClosure, NS_OK };
   ghostWindows.EnumerateEntries(ReportGhostWindowsEnumerator,
                                 &reportGhostWindowsEnumData);
   nsresult rv = reportGhostWindowsEnumData.rv;
   NS_ENSURE_SUCCESS(rv, rv);
   WindowPaths windowPaths;
   WindowPaths topWindowPaths;
   // Collect window memory usage.
   nsWindowSizes windowTotalSizes(nullptr);
   nsCOMPtr<amIAddonManager> addonManager;
   if (XRE_GetProcessType() == GeckoProcessType_Default) {
     // Only try to access the service from the main process.
     addonManager = do_GetService("@mozilla.org/addons/integration;1");
   }
   for (uint32_t i = 0; i < windows.Length(); i++) {
     rv = CollectWindowReports(windows[i], addonManager,
                               &windowTotalSizes, &ghostWindows,
                               &windowPaths, &topWindowPaths, aCb,
                               aClosure);
     NS_ENSURE_SUCCESS(rv, rv);
   }
   // Report JS memory usage.  We do this from here because the JS memory
   // reporter needs to be passed |windowPaths|.
   rv = xpc::JSReporter::CollectReports(&windowPaths, &topWindowPaths,
                                        aCb, aClosure);
   NS_ENSURE_SUCCESS(rv, rv);
 #define REPORT(_path, _amount, _desc)                                         \
   do {                                                                        \
     nsresult rv;                                                              \
     rv = aCb->Callback(EmptyCString(), NS_LITERAL_CSTRING(_path),             \
                        KIND_OTHER, UNITS_BYTES, _amount,                      \
                        NS_LITERAL_CSTRING(_desc), aClosure);                  \
     NS_ENSURE_SUCCESS(rv, rv);                                                \
   } while (0)
   REPORT("window-objects/dom/element-nodes", windowTotalSizes.mDOMElementNodesSize,
          "This is the sum of all windows' 'dom/element-nodes' numbers.");
   REPORT("window-objects/dom/text-nodes", windowTotalSizes.mDOMTextNodesSize,
          "This is the sum of all windows' 'dom/text-nodes' numbers.");
   REPORT("window-objects/dom/cdata-nodes", windowTotalSizes.mDOMCDATANodesSize,
          "This is the sum of all windows' 'dom/cdata-nodes' numbers.");
   REPORT("window-objects/dom/comment-nodes", windowTotalSizes.mDOMCommentNodesSize,
          "This is the sum of all windows' 'dom/comment-nodes' numbers.");
   REPORT("window-objects/dom/event-targets", windowTotalSizes.mDOMEventTargetsSize,
          "This is the sum of all windows' 'dom/event-targets' numbers.");
   REPORT("window-objects/dom/other", windowTotalSizes.mDOMOtherSize,
          "This is the sum of all windows' 'dom/other' numbers.");
   REPORT("window-objects/property-tables",
          windowTotalSizes.mPropertyTablesSize,
          "This is the sum of all windows' 'property-tables' numbers.");
   REPORT("window-objects/style-sheets", windowTotalSizes.mStyleSheetsSize,
          "This is the sum of all windows' 'style-sheets' numbers.");
   REPORT("window-objects/layout/pres-shell", windowTotalSizes.mLayoutPresShellSize,
          "This is the sum of all windows' 'layout/arenas' numbers.");
   REPORT("window-objects/layout/line-boxes",
          windowTotalSizes.mArenaStats.mLineBoxes,
          "This is the sum of all windows' 'layout/line-boxes' numbers.");
   REPORT("window-objects/layout/rule-nodes",
          windowTotalSizes.mArenaStats.mRuleNodes,
          "This is the sum of all windows' 'layout/rule-nodes' numbers.");
   REPORT("window-objects/layout/style-contexts",
          windowTotalSizes.mArenaStats.mStyleContexts,
          "This is the sum of all windows' 'layout/style-contexts' numbers.");
   REPORT("window-objects/layout/style-sets", windowTotalSizes.mLayoutStyleSetsSize,
          "This is the sum of all windows' 'layout/style-sets' numbers.");
   REPORT("window-objects/layout/text-runs", windowTotalSizes.mLayoutTextRunsSize,
          "This is the sum of all windows' 'layout/text-runs' numbers.");
   REPORT("window-objects/layout/pres-contexts", windowTotalSizes.mLayoutPresContextSize,
          "This is the sum of all windows' 'layout/pres-contexts' numbers.");
   size_t frameTotal = 0;
 #define FRAME_ID(classname)                \
   frameTotal += windowTotalSizes.mArenaStats.FRAME_ID_STAT_FIELD(classname);
 #include "nsFrameIdList.h"
 #undef FRAME_ID
   REPORT("window-objects/layout/frames", frameTotal,
          "Memory used for layout frames within windows. "
          "This is the sum of all windows' 'layout/frames/' numbers.");
 #undef REPORT
   return NS_OK;
 }
 uint32_t
 nsWindowMemoryReporter::GetGhostTimeout()
 {
   return Preferences::GetUint("memory.ghost_window_timeout_seconds", 60);
 }
 NS_IMETHODIMP
 nsWindowMemoryReporter::Observe(nsISupports *aSubject, const char *aTopic,
                                 const char16_t *aData)
 {
   if (!strcmp(aTopic, DOM_WINDOW_DESTROYED_TOPIC)) {
     ObserveDOMWindowDetached(aSubject);
   } else if (!strcmp(aTopic, "after-minimize-memory-usage")) {
     ObserveAfterMinimizeMemoryUsage();
   } else if (!strcmp(aTopic, "cycle-collector-begin")) {
     if (mCheckTimer) {
       mCheckTimerWaitingForCCEnd = true;
       KillCheckTimer();
     }
     mCycleCollectorIsRunning = true;
   } else if (!strcmp(aTopic, "cycle-collector-end")) {
     mCycleCollectorIsRunning = false;
     if (mCheckTimerWaitingForCCEnd) {
       mCheckTimerWaitingForCCEnd = false;
       AsyncCheckForGhostWindows();
     }
   } else {
     MOZ_ASSERT(false);
   }
   return NS_OK;
 }
 void
 nsWindowMemoryReporter::ObserveDOMWindowDetached(nsISupports* aWindow)
 {
   nsWeakPtr weakWindow = do_GetWeakReference(aWindow);
   if (!weakWindow) {
     NS_WARNING("Couldn't take weak reference to a window?");
     return;
   }
   mDetachedWindows.Put(weakWindow, TimeStamp());
   AsyncCheckForGhostWindows();
 }
 // static
 void
 nsWindowMemoryReporter::CheckTimerFired(nsITimer* aTimer, void* aClosure)
 {
   if (sWindowReporter) {
     MOZ_ASSERT(!sWindowReporter->mCycleCollectorIsRunning);
     sWindowReporter->CheckForGhostWindows();
   }
 }
 void
 nsWindowMemoryReporter::AsyncCheckForGhostWindows()
 {
   if (mCheckTimer) {
     return;
   }
   if (mCycleCollectorIsRunning) {
     mCheckTimerWaitingForCCEnd = true;
     return;
   }
   // If more than kTimeBetweenChecks seconds have elapsed since the last check,
   // timerDelay is 0.  Otherwise, it is kTimeBetweenChecks, reduced by the time
   // since the last check.  Reducing the delay by the time since the last check
   // prevents the timer from being completely starved if it is repeatedly killed
   // and restarted.
   int32_t timeSinceLastCheck = (TimeStamp::NowLoRes() - mLastCheckForGhostWindows).ToSeconds();
   int32_t timerDelay = (kTimeBetweenChecks - std::min(timeSinceLastCheck, kTimeBetweenChecks)) * PR_MSEC_PER_SEC;
   CallCreateInstance<nsITimer>("@mozilla.org/timer;1", getter_AddRefs(mCheckTimer));
   if (mCheckTimer) {
     mCheckTimer->InitWithFuncCallback(CheckTimerFired, nullptr,
                                       timerDelay, nsITimer::TYPE_ONE_SHOT);
   }
 }
 static PLDHashOperator
 BackdateTimeStampsEnumerator(nsISupports *aKey, TimeStamp &aTimeStamp,
                              void* aClosure)
 {
   TimeStamp *minTimeStamp = static_cast<TimeStamp*>(aClosure);
   if (!aTimeStamp.IsNull() && aTimeStamp > *minTimeStamp) {
     aTimeStamp = *minTimeStamp;
   }
   return PL_DHASH_NEXT;
 }
 void
 nsWindowMemoryReporter::ObserveAfterMinimizeMemoryUsage()
 {
   // Someone claims they've done enough GC/CCs so that all eligible windows
   // have been free'd.  So we deem that any windows which satisfy ghost
   // criteria (1) and (2) now satisfy criterion (3) as well.
   //
   // To effect this change, we'll backdate some of our timestamps.
   TimeStamp minTimeStamp = TimeStamp::Now() -
                            TimeDuration::FromSeconds(GetGhostTimeout());
   mDetachedWindows.Enumerate(BackdateTimeStampsEnumerator,
                              &minTimeStamp);
 }
 struct CheckForGhostWindowsEnumeratorData
 {
   nsTHashtable<nsCStringHashKey> *nonDetachedDomains;
   nsTHashtable<nsUint64HashKey> *ghostWindowIDs;
   nsIEffectiveTLDService *tldService;
   uint32_t ghostTimeout;
   TimeStamp now;
 };
 static PLDHashOperator
 CheckForGhostWindowsEnumerator(nsISupports *aKey, TimeStamp& aTimeStamp,
                                void* aClosure)
 {
   CheckForGhostWindowsEnumeratorData *data =
     static_cast<CheckForGhostWindowsEnumeratorData*>(aClosure);
   nsWeakPtr weakKey = do_QueryInterface(aKey);
   nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(weakKey);
   if (!window) {
     // The window object has been destroyed.  Stop tracking its weak ref in our
     // hashtable.
     return PL_DHASH_REMOVE;
   }
   // Avoid calling GetTop() if we have no outer window.  Nothing will break if
   // we do, but it will spew debug output, which can cause our test logs to
   // overflow.
   nsCOMPtr<nsIDOMWindow> top;
   if (window->GetOuterWindow()) {
     window->GetTop(getter_AddRefs(top));
   }
   if (top) {
     // The window is no longer detached, so we no longer want to track it.
     return PL_DHASH_REMOVE;
   }
   nsCOMPtr<nsIURI> uri = GetWindowURI(window);
   nsAutoCString domain;
   if (uri) {
     // GetBaseDomain works fine if |uri| is null, but it outputs a warning
     // which ends up overrunning the mochitest logs.
     data->tldService->GetBaseDomain(uri, 0, domain);
   }
   if (data->nonDetachedDomains->Contains(domain)) {
     // This window shares a domain with a non-detached window, so reset its
     // clock.
     aTimeStamp = TimeStamp();
   } else {
     // This window does not share a domain with a non-detached window, so it
     // meets ghost criterion (2).
     if (aTimeStamp.IsNull()) {
       // This may become a ghost window later; start its clock.
       aTimeStamp = data->now;
     } else if ((data->now - aTimeStamp).ToSeconds() > data->ghostTimeout) {
       // This definitely is a ghost window, so add it to ghostWindowIDs, if
       // that is not null.
       if (data->ghostWindowIDs) {
         nsCOMPtr<nsPIDOMWindow> pWindow = do_QueryInterface(window);
         if (pWindow) {
           data->ghostWindowIDs->PutEntry(pWindow->WindowID());
         }
       }
     }
   }
   return PL_DHASH_NEXT;
 }
 struct GetNonDetachedWindowDomainsEnumeratorData
 {
   nsTHashtable<nsCStringHashKey> *nonDetachedDomains;
   nsIEffectiveTLDService *tldService;
 };
 static PLDHashOperator
 GetNonDetachedWindowDomainsEnumerator(const uint64_t& aId, nsGlobalWindow* aWindow,
                                       void* aClosure)
 {
   GetNonDetachedWindowDomainsEnumeratorData *data =
     static_cast<GetNonDetachedWindowDomainsEnumeratorData*>(aClosure);
   // Null outer window implies null top, but calling GetTop() when there's no
   // outer window causes us to spew debug warnings.
   if (!aWindow->GetOuterWindow() || !aWindow->GetTop()) {
     // This window is detached, so we don't care about its domain.
     return PL_DHASH_NEXT;
   }
   nsCOMPtr<nsIURI> uri = GetWindowURI(aWindow);
   nsAutoCString domain;
   if (uri) {
     data->tldService->GetBaseDomain(uri, 0, domain);
   }
   data->nonDetachedDomains->PutEntry(domain);
   return PL_DHASH_NEXT;
 }
 /**
  * Iterate over mDetachedWindows and update it to reflect the current state of
  * the world.  In particular:
  *
  *   - Remove weak refs to windows which no longer exist.
  *
  *   - Remove references to windows which are no longer detached.
  *
  *   - Reset the timestamp on detached windows which share a domain with a
  *     non-detached window (they no longer meet ghost criterion (2)).
  *
  *   - If a window now meets ghost criterion (2) but didn't before, set its
  *     timestamp to now.
  *
  * Additionally, if aOutGhostIDs is not null, fill it with the window IDs of
  * all ghost windows we found.
  */
 void
 nsWindowMemoryReporter::CheckForGhostWindows(
   nsTHashtable<nsUint64HashKey> *aOutGhostIDs /* = nullptr */)
 {
   nsCOMPtr<nsIEffectiveTLDService> tldService = do_GetService(
     NS_EFFECTIVETLDSERVICE_CONTRACTID);
   if (!tldService) {
     NS_WARNING("Couldn't get TLDService.");
     return;
   }
   nsGlobalWindow::WindowByIdTable *windowsById =
     nsGlobalWindow::GetWindowsTable();
   if (!windowsById) {
     NS_WARNING("GetWindowsTable returned null");
     return;
   }
   mLastCheckForGhostWindows = TimeStamp::NowLoRes();
   KillCheckTimer();
   nsTHashtable<nsCStringHashKey> nonDetachedWindowDomains;
   // Populate nonDetachedWindowDomains.
   GetNonDetachedWindowDomainsEnumeratorData nonDetachedEnumData =
     { &nonDetachedWindowDomains, tldService };
   windowsById->EnumerateRead(GetNonDetachedWindowDomainsEnumerator,
                              &nonDetachedEnumData);
   // Update mDetachedWindows and write the ghost window IDs into aOutGhostIDs,
   // if it's not null.
   CheckForGhostWindowsEnumeratorData ghostEnumData =
     { &nonDetachedWindowDomains, aOutGhostIDs, tldService,
       GetGhostTimeout(), mLastCheckForGhostWindows };
   mDetachedWindows.Enumerate(CheckForGhostWindowsEnumerator,
                              &ghostEnumData);
 }
 NS_IMPL_ISUPPORTS(nsWindowMemoryReporter::GhostWindowsReporter,
                   nsIMemoryReporter)
 /* static */ int64_t
 nsWindowMemoryReporter::GhostWindowsReporter::DistinguishedAmount()
 {
   nsTHashtable<nsUint64HashKey> ghostWindows;
   sWindowReporter->CheckForGhostWindows(&ghostWindows);
   return ghostWindows.Count();
 }
 void
 nsWindowMemoryReporter::KillCheckTimer()
 {
   if (mCheckTimer) {
     mCheckTimer->Cancel();
     mCheckTimer = nullptr;
   }
 }
 #ifdef DEBUG
 static PLDHashOperator
 UnlinkGhostWindowsEnumerator(nsUint64HashKey* aIDHashKey, void *)
 {
   nsGlobalWindow::WindowByIdTable* windowsById =
     nsGlobalWindow::GetWindowsTable();
   if (!windowsById) {
     return PL_DHASH_NEXT;
   }
   nsRefPtr<nsGlobalWindow> window = windowsById->Get(aIDHashKey->GetKey());
   if (window) {
     window->RiskyUnlink();
   }
   return PL_DHASH_NEXT;
 }
 /* static */ void
 nsWindowMemoryReporter::UnlinkGhostWindows()
 {
   if (!sWindowReporter) {
     return;
   }
   nsGlobalWindow::WindowByIdTable* windowsById =
     nsGlobalWindow::GetWindowsTable();
   if (!windowsById) {
     return;
   }
   // Hold on to every window in memory so that window objects can't be
   // destroyed while we're calling the UnlinkGhostWindows callback.
   WindowArray windows;
   windowsById->Enumerate(GetWindows, &windows);
   // Get the IDs of all the "ghost" windows, and unlink them all.
   nsTHashtable<nsUint64HashKey> ghostWindows;
   sWindowReporter->CheckForGhostWindows(&ghostWindows);
   ghostWindows.EnumerateEntries(UnlinkGhostWindowsEnumerator, nullptr);
 }
 #endif

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dom/base/nsWindowMemoryReporter.cpp