The Tor Browser: layout/style/nsLayoutStylesheetCache.cpp@97036ab72558 (annotated)

layout/style/nsLayoutStylesheetCache.cpp@97036ab72558 (annotated)

layout/style/nsLayoutStylesheetCache.cpp

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.

 /* -*- 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 "nsLayoutStylesheetCache.h"
 #include "nsAppDirectoryServiceDefs.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/css/Loader.h"
 #include "nsIFile.h"
 #include "nsNetUtil.h"
 #include "nsIObserverService.h"
 #include "nsServiceManagerUtils.h"
 #include "nsIXULRuntime.h"
 #include "nsCSSStyleSheet.h"
 using namespace mozilla;
 static bool sNumberControlEnabled;
 #define NUMBER_CONTROL_PREF "dom.forms.number"
 NS_IMPL_ISUPPORTS(
   nsLayoutStylesheetCache, nsIObserver, nsIMemoryReporter)
 nsresult
 nsLayoutStylesheetCache::Observe(nsISupports* aSubject,
                             const char* aTopic,
                             const char16_t* aData)
 {
   if (!strcmp(aTopic, "profile-before-change")) {
     mUserContentSheet = nullptr;
     mUserChromeSheet  = nullptr;
   }
   else if (!strcmp(aTopic, "profile-do-change")) {
     InitFromProfile();
   }
   else if (strcmp(aTopic, "chrome-flush-skin-caches") == 0 ||
            strcmp(aTopic, "chrome-flush-caches") == 0) {
     mScrollbarsSheet = nullptr;
     mFormsSheet = nullptr;
     mNumberControlSheet = nullptr;
   }
   else {
     NS_NOTREACHED("Unexpected observer topic.");
   }
   return NS_OK;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::ScrollbarsSheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   if (!gStyleCache->mScrollbarsSheet) {
     nsCOMPtr<nsIURI> sheetURI;
     NS_NewURI(getter_AddRefs(sheetURI),
               NS_LITERAL_CSTRING("chrome://global/skin/scrollbars.css"));
     // Scrollbars don't need access to unsafe rules
     if (sheetURI)
       LoadSheet(sheetURI, gStyleCache->mScrollbarsSheet, false);
     NS_ASSERTION(gStyleCache->mScrollbarsSheet, "Could not load scrollbars.css.");
   }
   return gStyleCache->mScrollbarsSheet;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::FormsSheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   if (!gStyleCache->mFormsSheet) {
     nsCOMPtr<nsIURI> sheetURI;
       NS_NewURI(getter_AddRefs(sheetURI),
                 NS_LITERAL_CSTRING("resource://gre-resources/forms.css"));
     // forms.css needs access to unsafe rules
     if (sheetURI)
       LoadSheet(sheetURI, gStyleCache->mFormsSheet, true);
     NS_ASSERTION(gStyleCache->mFormsSheet, "Could not load forms.css.");
   }
   return gStyleCache->mFormsSheet;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::NumberControlSheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   if (!sNumberControlEnabled) {
     return nullptr;
   }
   if (!gStyleCache->mNumberControlSheet) {
     nsCOMPtr<nsIURI> sheetURI;
     NS_NewURI(getter_AddRefs(sheetURI),
               NS_LITERAL_CSTRING("resource://gre-resources/number-control.css"));
     if (sheetURI)
       LoadSheet(sheetURI, gStyleCache->mNumberControlSheet, false);
     NS_ASSERTION(gStyleCache->mNumberControlSheet, "Could not load number-control.css");
   }
   return gStyleCache->mNumberControlSheet;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::UserContentSheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   return gStyleCache->mUserContentSheet;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::UserChromeSheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   return gStyleCache->mUserChromeSheet;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::UASheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   return gStyleCache->mUASheet;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::QuirkSheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   return gStyleCache->mQuirkSheet;
 }
 nsCSSStyleSheet*
 nsLayoutStylesheetCache::FullScreenOverrideSheet()
 {
   EnsureGlobal();
   if (!gStyleCache)
     return nullptr;
   return gStyleCache->mFullScreenOverrideSheet;
 }
 void
 nsLayoutStylesheetCache::Shutdown()
 {
   NS_IF_RELEASE(gCSSLoader);
   NS_IF_RELEASE(gStyleCache);
 }
 MOZ_DEFINE_MALLOC_SIZE_OF(LayoutStylesheetCacheMallocSizeOf)
 NS_IMETHODIMP
 nsLayoutStylesheetCache::CollectReports(nsIHandleReportCallback* aHandleReport,
                                         nsISupports* aData)
 {
   return MOZ_COLLECT_REPORT(
     "explicit/layout/style-sheet-cache", KIND_HEAP, UNITS_BYTES,
     SizeOfIncludingThis(LayoutStylesheetCacheMallocSizeOf),
     "Memory used for some built-in style sheets.");
 }
 size_t
 nsLayoutStylesheetCache::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
 {
   size_t n = aMallocSizeOf(this);
   #define MEASURE(s) n += s ? s->SizeOfIncludingThis(aMallocSizeOf) : 0;
   MEASURE(mScrollbarsSheet);
   MEASURE(mFormsSheet);
   MEASURE(mNumberControlSheet);
   MEASURE(mUserContentSheet);
   MEASURE(mUserChromeSheet);
   MEASURE(mUASheet);
   MEASURE(mQuirkSheet);
   MEASURE(mFullScreenOverrideSheet);
   // Measurement of the following members may be added later if DMD finds it is
   // worthwhile:
   // - gCSSLoader
   return n;
 }
 nsLayoutStylesheetCache::nsLayoutStylesheetCache()
 {
   nsCOMPtr<nsIObserverService> obsSvc =
     mozilla::services::GetObserverService();
   NS_ASSERTION(obsSvc, "No global observer service?");
   if (obsSvc) {
     obsSvc->AddObserver(this, "profile-before-change", false);
     obsSvc->AddObserver(this, "profile-do-change", false);
     obsSvc->AddObserver(this, "chrome-flush-skin-caches", false);
     obsSvc->AddObserver(this, "chrome-flush-caches", false);
   }
   InitFromProfile();
   // And make sure that we load our UA sheets.  No need to do this
   // per-profile, since they're profile-invariant.
   nsCOMPtr<nsIURI> uri;
   NS_NewURI(getter_AddRefs(uri), "resource://gre-resources/ua.css");
   if (uri) {
     LoadSheet(uri, mUASheet, true);
   }
   NS_ASSERTION(mUASheet, "Could not load ua.css");
   NS_NewURI(getter_AddRefs(uri), "resource://gre-resources/quirk.css");
   if (uri) {
     LoadSheet(uri, mQuirkSheet, true);
   }
   NS_ASSERTION(mQuirkSheet, "Could not load quirk.css");
   NS_NewURI(getter_AddRefs(uri), "resource://gre-resources/full-screen-override.css");
   if (uri) {
     LoadSheet(uri, mFullScreenOverrideSheet, true);
   }
   NS_ASSERTION(mFullScreenOverrideSheet, "Could not load full-screen-override.css");
 }
 nsLayoutStylesheetCache::~nsLayoutStylesheetCache()
 {
   mozilla::UnregisterWeakMemoryReporter(this);
   gStyleCache = nullptr;
 }
 void
 nsLayoutStylesheetCache::InitMemoryReporter()
 {
   mozilla::RegisterWeakMemoryReporter(this);
 }
 void
 nsLayoutStylesheetCache::EnsureGlobal()
 {
   if (gStyleCache) return;
   gStyleCache = new nsLayoutStylesheetCache();
   if (!gStyleCache) return;
   NS_ADDREF(gStyleCache);
   gStyleCache->InitMemoryReporter();
   Preferences::AddBoolVarCache(&sNumberControlEnabled, NUMBER_CONTROL_PREF,
                                true);
 }
 void
 nsLayoutStylesheetCache::InitFromProfile()
 {
   nsCOMPtr<nsIXULRuntime> appInfo = do_GetService("@mozilla.org/xre/app-info;1");
   if (appInfo) {
     bool inSafeMode = false;
     appInfo->GetInSafeMode(&inSafeMode);
     if (inSafeMode)
       return;
   }
   nsCOMPtr<nsIFile> contentFile;
   nsCOMPtr<nsIFile> chromeFile;
   NS_GetSpecialDirectory(NS_APP_USER_CHROME_DIR,
                          getter_AddRefs(contentFile));
   if (!contentFile) {
     // if we don't have a profile yet, that's OK!
     return;
   }
   contentFile->Clone(getter_AddRefs(chromeFile));
   if (!chromeFile) return;
   contentFile->Append(NS_LITERAL_STRING("userContent.css"));
   chromeFile->Append(NS_LITERAL_STRING("userChrome.css"));
   LoadSheetFile(contentFile, mUserContentSheet);
   LoadSheetFile(chromeFile, mUserChromeSheet);
 }
 void
 nsLayoutStylesheetCache::LoadSheetFile(nsIFile* aFile, nsRefPtr<nsCSSStyleSheet> &aSheet)
 {
   bool exists = false;
   aFile->Exists(&exists);
   if (!exists) return;
   nsCOMPtr<nsIURI> uri;
   NS_NewFileURI(getter_AddRefs(uri), aFile);
   LoadSheet(uri, aSheet, false);
 }
 void
 nsLayoutStylesheetCache::LoadSheet(nsIURI* aURI,
                                    nsRefPtr<nsCSSStyleSheet> &aSheet,
                                    bool aEnableUnsafeRules)
 {
   if (!aURI) {
     NS_ERROR("Null URI. Out of memory?");
     return;
   }
   if (!gCSSLoader) {
     gCSSLoader = new mozilla::css::Loader();
     NS_IF_ADDREF(gCSSLoader);
   }
   if (gCSSLoader) {
     gCSSLoader->LoadSheetSync(aURI, aEnableUnsafeRules, true,
                               getter_AddRefs(aSheet));
   }
 }
 nsLayoutStylesheetCache*
 nsLayoutStylesheetCache::gStyleCache = nullptr;
 mozilla::css::Loader*
 nsLayoutStylesheetCache::gCSSLoader = nullptr;

The Tor Browser / annotate

layout/style/nsLayoutStylesheetCache.cpp@97036ab72558 (annotated)

layout/style/nsLayoutStylesheetCache.cpp