Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3084 insertions, 0 deletions

diff --git a/gfx/thebes/gfxPlatformFontList.cpp b/gfx/thebes/gfxPlatformFontList.cpp
new file mode 100644
index 0000000000..532735c824
--- /dev/null
+++ b/gfx/thebes/gfxPlatformFontList.cpp
@@ -0,0 +1,3084 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * 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 "mozilla/Logging.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/intl/Locale.h"
+#include "mozilla/intl/LocaleService.h"
+#include "mozilla/intl/OSPreferences.h"
+
+#include "gfxPlatformFontList.h"
+#include "gfxTextRun.h"
+#include "gfxUserFontSet.h"
+#include "SharedFontList-impl.h"
+
+#include "GeckoProfiler.h"
+#include "nsCRT.h"
+#include "nsGkAtoms.h"
+#include "nsPresContext.h"
+#include "nsServiceManagerUtils.h"
+#include "nsUnicharUtils.h"
+#include "nsUnicodeProperties.h"
+#include "nsXULAppAPI.h"
+
+#include "mozilla/AppShutdown.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/BinarySearch.h"
+#include "mozilla/Likely.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/dom/BlobImpl.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/ContentProcessMessageManager.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/ipc/FileDescriptorUtils.h"
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/TextUtils.h"
+#include "mozilla/Unused.h"
+
+#include "base/eintr_wrapper.h"
+
+#include <locale.h>
+#include <numeric>
+
+using namespace mozilla;
+using mozilla::intl::Locale;
+using mozilla::intl::LocaleParser;
+using mozilla::intl::LocaleService;
+using mozilla::intl::OSPreferences;
+
+#define LOG_FONTLIST(args) \
+  MOZ_LOG(gfxPlatform::GetLog(eGfxLog_fontlist), LogLevel::Debug, args)
+#define LOG_FONTLIST_ENABLED() \
+  MOZ_LOG_TEST(gfxPlatform::GetLog(eGfxLog_fontlist), LogLevel::Debug)
+#define LOG_FONTINIT(args) \
+  MOZ_LOG(gfxPlatform::GetLog(eGfxLog_fontinit), LogLevel::Debug, args)
+#define LOG_FONTINIT_ENABLED() \
+  MOZ_LOG_TEST(gfxPlatform::GetLog(eGfxLog_fontinit), LogLevel::Debug)
+
+gfxPlatformFontList* gfxPlatformFontList::sPlatformFontList = nullptr;
+
+// Character ranges that require complex-script shaping support in the font,
+// and so should be masked out by ReadCMAP if the necessary layout tables
+// are not present.
+// Currently used by the Mac and FT2 implementations only, but probably should
+// be supported on Windows as well.
+const gfxFontEntry::ScriptRange gfxPlatformFontList::sComplexScriptRanges[] = {
+    // Actually, now that harfbuzz supports presentation-forms shaping for
+    // Arabic, we can render it without layout tables. So maybe we don't
+    // want to mask the basic Arabic block here?
+    // This affects the arabic-fallback-*.html reftests, which rely on
+    // loading a font that *doesn't* have any GSUB table.
+    {0x0600, 0x06FF, 1, {TRUETYPE_TAG('a', 'r', 'a', 'b'), 0, 0}},
+    {0x0700, 0x074F, 1, {TRUETYPE_TAG('s', 'y', 'r', 'c'), 0, 0}},
+    {0x0750, 0x077F, 1, {TRUETYPE_TAG('a', 'r', 'a', 'b'), 0, 0}},
+    {0x08A0, 0x08FF, 1, {TRUETYPE_TAG('a', 'r', 'a', 'b'), 0, 0}},
+    {0x0900,
+     0x097F,
+     2,
+     {TRUETYPE_TAG('d', 'e', 'v', '2'), TRUETYPE_TAG('d', 'e', 'v', 'a'), 0}},
+    {0x0980,
+     0x09FF,
+     2,
+     {TRUETYPE_TAG('b', 'n', 'g', '2'), TRUETYPE_TAG('b', 'e', 'n', 'g'), 0}},
+    {0x0A00,
+     0x0A7F,
+     2,
+     {TRUETYPE_TAG('g', 'u', 'r', '2'), TRUETYPE_TAG('g', 'u', 'r', 'u'), 0}},
+    {0x0A80,
+     0x0AFF,
+     2,
+     {TRUETYPE_TAG('g', 'j', 'r', '2'), TRUETYPE_TAG('g', 'u', 'j', 'r'), 0}},
+    {0x0B00,
+     0x0B7F,
+     2,
+     {TRUETYPE_TAG('o', 'r', 'y', '2'), TRUETYPE_TAG('o', 'r', 'y', 'a'), 0}},
+    {0x0B80,
+     0x0BFF,
+     2,
+     {TRUETYPE_TAG('t', 'm', 'l', '2'), TRUETYPE_TAG('t', 'a', 'm', 'l'), 0}},
+    {0x0C00,
+     0x0C7F,
+     2,
+     {TRUETYPE_TAG('t', 'e', 'l', '2'), TRUETYPE_TAG('t', 'e', 'l', 'u'), 0}},
+    {0x0C80,
+     0x0CFF,
+     2,
+     {TRUETYPE_TAG('k', 'n', 'd', '2'), TRUETYPE_TAG('k', 'n', 'd', 'a'), 0}},
+    {0x0D00,
+     0x0D7F,
+     2,
+     {TRUETYPE_TAG('m', 'l', 'm', '2'), TRUETYPE_TAG('m', 'l', 'y', 'm'), 0}},
+    {0x0D80, 0x0DFF, 1, {TRUETYPE_TAG('s', 'i', 'n', 'h'), 0, 0}},
+    {0x0E80, 0x0EFF, 1, {TRUETYPE_TAG('l', 'a', 'o', ' '), 0, 0}},
+    {0x0F00, 0x0FFF, 1, {TRUETYPE_TAG('t', 'i', 'b', 't'), 0, 0}},
+    {0x1000,
+     0x109f,
+     2,
+     {TRUETYPE_TAG('m', 'y', 'm', 'r'), TRUETYPE_TAG('m', 'y', 'm', '2'), 0}},
+    {0x1780, 0x17ff, 1, {TRUETYPE_TAG('k', 'h', 'm', 'r'), 0, 0}},
+    // Khmer Symbols (19e0..19ff) don't seem to need any special shaping
+    {0xaa60,
+     0xaa7f,
+     2,
+     {TRUETYPE_TAG('m', 'y', 'm', 'r'), TRUETYPE_TAG('m', 'y', 'm', '2'), 0}},
+    // Thai seems to be "renderable" without AAT morphing tables
+    {0, 0, 0, {0, 0, 0}}  // terminator
+};
+
+static const char* kObservedPrefs[] = {"font.", "font.name-list.",
+                                       "intl.accept_languages",  // hmmmm...
+                                       nullptr};
+
+static const char kFontSystemWhitelistPref[] = "font.system.whitelist";
+
+static const char kCJKFallbackOrderPref[] = "font.cjk_pref_fallback_order";
+
+// xxx - this can probably be eliminated by reworking pref font handling code
+static const char* gPrefLangNames[] = {
+#define FONT_PREF_LANG(enum_id_, str_, atom_id_) str_
+#include "gfxFontPrefLangList.h"
+#undef FONT_PREF_LANG
+};
+
+static_assert(MOZ_ARRAY_LENGTH(gPrefLangNames) == uint32_t(eFontPrefLang_Count),
+              "size of pref lang name array doesn't match pref lang enum size");
+
+class gfxFontListPrefObserver final : public nsIObserver {
+  ~gfxFontListPrefObserver() = default;
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+};
+
+static void FontListPrefChanged(const char* aPref, void* aData = nullptr) {
+  // XXX this could be made to only clear out the cache for the prefs that were
+  // changed but it probably isn't that big a deal.
+  gfxPlatformFontList::PlatformFontList()->ClearLangGroupPrefFonts();
+  gfxFontCache::GetCache()->Flush();
+}
+
+static gfxFontListPrefObserver* gFontListPrefObserver = nullptr;
+
+NS_IMPL_ISUPPORTS(gfxFontListPrefObserver, nsIObserver)
+
+#define LOCALES_CHANGED_TOPIC "intl:system-locales-changed"
+
+NS_IMETHODIMP
+gfxFontListPrefObserver::Observe(nsISupports* aSubject, const char* aTopic,
+                                 const char16_t* aData) {
+  NS_ASSERTION(!strcmp(aTopic, LOCALES_CHANGED_TOPIC), "invalid topic");
+  FontListPrefChanged(nullptr);
+
+  if (XRE_IsParentProcess()) {
+    gfxPlatform::ForceGlobalReflow(gfxPlatform::NeedsReframe::No);
+  }
+  return NS_OK;
+}
+
+MOZ_DEFINE_MALLOC_SIZE_OF(FontListMallocSizeOf)
+
+NS_IMPL_ISUPPORTS(gfxPlatformFontList::MemoryReporter, nsIMemoryReporter)
+
+NS_IMETHODIMP
+gfxPlatformFontList::MemoryReporter::CollectReports(
+    nsIHandleReportCallback* aHandleReport, nsISupports* aData,
+    bool aAnonymize) {
+  FontListSizes sizes;
+  sizes.mFontListSize = 0;
+  sizes.mFontTableCacheSize = 0;
+  sizes.mCharMapsSize = 0;
+  sizes.mLoaderSize = 0;
+  sizes.mSharedSize = 0;
+
+  gfxPlatformFontList::PlatformFontList()->AddSizeOfIncludingThis(
+      &FontListMallocSizeOf, &sizes);
+
+  MOZ_COLLECT_REPORT(
+      "explicit/gfx/font-list", KIND_HEAP, UNITS_BYTES, sizes.mFontListSize,
+      "Memory used to manage the list of font families and faces.");
+
+  MOZ_COLLECT_REPORT(
+      "explicit/gfx/font-charmaps", KIND_HEAP, UNITS_BYTES, sizes.mCharMapsSize,
+      "Memory used to record the character coverage of individual fonts.");
+
+  if (sizes.mFontTableCacheSize) {
+    MOZ_COLLECT_REPORT(
+        "explicit/gfx/font-tables", KIND_HEAP, UNITS_BYTES,
+        sizes.mFontTableCacheSize,
+        "Memory used for cached font metrics and layout tables.");
+  }
+
+  if (sizes.mLoaderSize) {
+    MOZ_COLLECT_REPORT("explicit/gfx/font-loader", KIND_HEAP, UNITS_BYTES,
+                       sizes.mLoaderSize,
+                       "Memory used for (platform-specific) font loader.");
+  }
+
+  if (sizes.mSharedSize) {
+    MOZ_COLLECT_REPORT(
+        "font-list-shmem", KIND_NONHEAP, UNITS_BYTES, sizes.mSharedSize,
+        "Shared memory for system font list and character coverage data.");
+  }
+
+  return NS_OK;
+}
+
+PRThread* gfxPlatformFontList::sInitFontListThread = nullptr;
+
+static void InitFontListCallback(void* aFontList) {
+  AUTO_PROFILER_REGISTER_THREAD("InitFontList");
+  PR_SetCurrentThreadName("InitFontList");
+
+  if (!static_cast<gfxPlatformFontList*>(aFontList)->InitFontList()) {
+    gfxPlatformFontList::Shutdown();
+  }
+}
+
+/* static */
+bool gfxPlatformFontList::Initialize(gfxPlatformFontList* aList) {
+  sPlatformFontList = aList;
+  if (XRE_IsParentProcess() &&
+      StaticPrefs::gfx_font_list_omt_enabled_AtStartup() &&
+      StaticPrefs::gfx_e10s_font_list_shared_AtStartup() &&
+      !gfxPlatform::InSafeMode()) {
+    sInitFontListThread = PR_CreateThread(
+        PR_USER_THREAD, InitFontListCallback, aList, PR_PRIORITY_NORMAL,
+        PR_GLOBAL_THREAD, PR_JOINABLE_THREAD, 0);
+    return true;
+  }
+  if (aList->InitFontList()) {
+    return true;
+  }
+  Shutdown();
+  return false;
+}
+
+gfxPlatformFontList::gfxPlatformFontList(bool aNeedFullnamePostscriptNames)
+    : mLock("gfxPlatformFontList lock"),
+      mFontFamilies(64),
+      mOtherFamilyNames(16),
+      mSharedCmaps(8) {
+  if (aNeedFullnamePostscriptNames) {
+    mExtraNames = MakeUnique<ExtraNames>();
+  }
+
+  mLangService = nsLanguageAtomService::GetService();
+
+  LoadBadUnderlineList();
+
+  mFontPrefs = MakeUnique<FontPrefs>();
+
+  gfxFontUtils::GetPrefsFontList(kFontSystemWhitelistPref, mEnabledFontsList);
+  mFontFamilyWhitelistActive = !mEnabledFontsList.IsEmpty();
+
+  // pref changes notification setup
+  NS_ASSERTION(!gFontListPrefObserver,
+               "There has been font list pref observer already");
+  gFontListPrefObserver = new gfxFontListPrefObserver();
+  NS_ADDREF(gFontListPrefObserver);
+
+  Preferences::RegisterPrefixCallbacks(FontListPrefChanged, kObservedPrefs);
+
+  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+  if (obs) {
+    obs->AddObserver(gFontListPrefObserver, LOCALES_CHANGED_TOPIC, false);
+  }
+
+  // Only the parent process listens for whitelist changes; it will then
+  // notify its children to rebuild their font lists.
+  if (XRE_IsParentProcess()) {
+    Preferences::RegisterCallback(FontWhitelistPrefChanged,
+                                  kFontSystemWhitelistPref);
+  }
+
+  RegisterStrongMemoryReporter(new MemoryReporter());
+
+  // initialize lang group pref font defaults (i.e. serif/sans-serif)
+  mDefaultGenericsLangGroup.AppendElements(ArrayLength(gPrefLangNames));
+  for (uint32_t i = 0; i < ArrayLength(gPrefLangNames); i++) {
+    nsAutoCString prefDefaultFontType("font.default.");
+    prefDefaultFontType.Append(GetPrefLangName(eFontPrefLang(i)));
+    nsAutoCString serifOrSans;
+    Preferences::GetCString(prefDefaultFontType.get(), serifOrSans);
+    if (serifOrSans.EqualsLiteral("sans-serif")) {
+      mDefaultGenericsLangGroup[i] = StyleGenericFontFamily::SansSerif;
+    } else {
+      mDefaultGenericsLangGroup[i] = StyleGenericFontFamily::Serif;
+    }
+  }
+}
+
+gfxPlatformFontList::~gfxPlatformFontList() {
+  // We take the lock here because it's possible the InitFontList thread is
+  // still running, in which case we need to wait for it to finish; this will
+  // block until the lock becomes available, ensuring we don't destroy things
+  // the initialization thread is using.
+  AutoLock lock(mLock);
+
+  mSharedCmaps.Clear();
+  ClearLangGroupPrefFontsLocked();
+
+  NS_ASSERTION(gFontListPrefObserver, "There is no font list pref observer");
+
+  Preferences::UnregisterPrefixCallbacks(FontListPrefChanged, kObservedPrefs);
+
+  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+  if (obs) {
+    obs->RemoveObserver(gFontListPrefObserver, LOCALES_CHANGED_TOPIC);
+  }
+
+  if (XRE_IsParentProcess()) {
+    Preferences::UnregisterCallback(FontWhitelistPrefChanged,
+                                    kFontSystemWhitelistPref);
+  }
+  NS_RELEASE(gFontListPrefObserver);
+}
+
+/* static */
+void gfxPlatformFontList::FontWhitelistPrefChanged(const char* aPref,
+                                                   void* aClosure) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  auto* pfl = gfxPlatformFontList::PlatformFontList();
+  pfl->UpdateFontList(true);
+  dom::ContentParent::NotifyUpdatedFonts(true);
+}
+
+void gfxPlatformFontList::ApplyWhitelist() {
+  uint32_t numFonts = mEnabledFontsList.Length();
+  if (!mFontFamilyWhitelistActive) {
+    return;
+  }
+  nsTHashSet<nsCString> familyNamesWhitelist;
+  for (uint32_t i = 0; i < numFonts; i++) {
+    nsAutoCString key;
+    ToLowerCase(mEnabledFontsList[i], key);
+    familyNamesWhitelist.Insert(key);
+  }
+  AutoTArray<RefPtr<gfxFontFamily>, 128> accepted;
+  bool whitelistedFontFound = false;
+  for (const auto& entry : mFontFamilies) {
+    if (entry.GetData()->IsHidden()) {
+      // Hidden system fonts are exempt from whitelisting, but don't count
+      // towards determining whether we "kept" any (user-visible) fonts
+      accepted.AppendElement(entry.GetData());
+      continue;
+    }
+    nsAutoCString fontFamilyName(entry.GetKey());
+    ToLowerCase(fontFamilyName);
+    if (familyNamesWhitelist.Contains(fontFamilyName)) {
+      accepted.AppendElement(entry.GetData());
+      whitelistedFontFound = true;
+    }
+  }
+  if (!whitelistedFontFound) {
+    // No whitelisted fonts found! Ignore the whitelist.
+    return;
+  }
+  // Replace the original full list with the accepted subset.
+  mFontFamilies.Clear();
+  for (auto& f : accepted) {
+    nsAutoCString fontFamilyName(f->Name());
+    ToLowerCase(fontFamilyName);
+    mFontFamilies.InsertOrUpdate(fontFamilyName, std::move(f));
+  }
+}
+
+void gfxPlatformFontList::ApplyWhitelist(
+    nsTArray<fontlist::Family::InitData>& aFamilies) {
+  mLock.AssertCurrentThreadIn();
+  if (!mFontFamilyWhitelistActive) {
+    return;
+  }
+  nsTHashSet<nsCString> familyNamesWhitelist;
+  for (const auto& item : mEnabledFontsList) {
+    nsAutoCString key;
+    ToLowerCase(item, key);
+    familyNamesWhitelist.Insert(key);
+  }
+  AutoTArray<fontlist::Family::InitData, 128> accepted;
+  bool keptNonHidden = false;
+  for (auto& f : aFamilies) {
+    if (f.mVisibility == FontVisibility::Hidden ||
+        familyNamesWhitelist.Contains(f.mKey)) {
+      accepted.AppendElement(f);
+      if (f.mVisibility != FontVisibility::Hidden) {
+        keptNonHidden = true;
+      }
+    }
+  }
+  if (!keptNonHidden) {
+    // No (visible) families were whitelisted: ignore the whitelist
+    // and just leave the fontlist unchanged.
+    return;
+  }
+  aFamilies = std::move(accepted);
+}
+
+bool gfxPlatformFontList::FamilyInList(const nsACString& aName,
+                                       const char* aList[], size_t aCount) {
+  size_t result;
+  return BinarySearchIf(
+      aList, 0, aCount,
+      [&](const char* const aVal) -> int {
+        return nsCaseInsensitiveUTF8StringComparator(
+            aName.BeginReading(), aVal, aName.Length(), strlen(aVal));
+      },
+      &result);
+}
+
+void gfxPlatformFontList::CheckFamilyList(const char* aList[], size_t aCount) {
+#ifdef DEBUG
+  MOZ_ASSERT(aCount > 0, "empty font family list?");
+  const char* a = aList[0];
+  uint32_t aLen = strlen(a);
+  for (size_t i = 1; i < aCount; ++i) {
+    const char* b = aList[i];
+    uint32_t bLen = strlen(b);
+    MOZ_ASSERT(nsCaseInsensitiveUTF8StringComparator(a, b, aLen, bLen) < 0,
+               "incorrectly sorted font family list!");
+    a = b;
+    aLen = bLen;
+  }
+#endif
+}
+
+bool gfxPlatformFontList::AddWithLegacyFamilyName(const nsACString& aLegacyName,
+                                                  gfxFontEntry* aFontEntry,
+                                                  FontVisibility aVisibility) {
+  mLock.AssertCurrentThreadIn();
+  bool added = false;
+  nsAutoCString key;
+  ToLowerCase(aLegacyName, key);
+  mOtherFamilyNames
+      .LookupOrInsertWith(key,
+                          [&] {
+                            RefPtr<gfxFontFamily> family =
+                                CreateFontFamily(aLegacyName, aVisibility);
+                            // We don't want the family to search for faces,
+                            // we're adding them directly here.
+                            family->SetHasStyles(true);
+                            // And we don't want it to attempt to search for
+                            // legacy names, because we've already done that
+                            // (and this is the result).
+                            family->SetCheckedForLegacyFamilyNames(true);
+                            added = true;
+                            return family;
+                          })
+      ->AddFontEntry(aFontEntry->Clone());
+  return added;
+}
+
+bool gfxPlatformFontList::InitFontList() {
+  // If the startup font-list-init thread is still running, we need to wait
+  // for it to finish before trying to reinitialize here.
+  if (sInitFontListThread && !IsInitFontListThread()) {
+    PR_JoinThread(sInitFontListThread);
+    sInitFontListThread = nullptr;
+  }
+
+  AutoLock lock(mLock);
+
+  if (LOG_FONTINIT_ENABLED()) {
+    LOG_FONTINIT(("(fontinit) system fontlist initialization\n"));
+  }
+
+  if (IsInitialized()) {
+    // Font-list reinitialization always occurs on the main thread, in response
+    // to a change notification; it's only the initial creation during startup
+    // that may be on another thread.
+    MOZ_ASSERT(NS_IsMainThread());
+
+    // Rebuilding fontlist so clear out font/word caches.
+    gfxFontCache* fontCache = gfxFontCache::GetCache();
+    if (fontCache) {
+      fontCache->FlushShapedWordCaches();
+      fontCache->Flush();
+    }
+
+    gfxPlatform::PurgeSkiaFontCache();
+
+    // There's no need to broadcast this reflow request to child processes, as
+    // ContentParent::NotifyUpdatedFonts deals with it by re-entering into this
+    // function on child processes.
+    ForceGlobalReflowLocked(gfxPlatform::NeedsReframe::Yes,
+                            gfxPlatform::BroadcastToChildren::No);
+
+    mAliasTable.Clear();
+    mLocalNameTable.Clear();
+
+    CancelLoadCmapsTask();
+    mStartedLoadingCmapsFrom = 0xffffffffu;
+
+    CancelInitOtherFamilyNamesTask();
+    mFontFamilies.Clear();
+    mOtherFamilyNames.Clear();
+    mOtherFamilyNamesInitialized = false;
+
+    if (mExtraNames) {
+      mExtraNames->mFullnames.Clear();
+      mExtraNames->mPostscriptNames.Clear();
+    }
+    mFaceNameListsInitialized = false;
+    ClearLangGroupPrefFontsLocked();
+    CancelLoader();
+
+    // Clear cached family records that will no longer be valid.
+    for (auto& f : mReplacementCharFallbackFamily) {
+      f = FontFamily();
+    }
+
+    gfxFontUtils::GetPrefsFontList(kFontSystemWhitelistPref, mEnabledFontsList);
+    mFontFamilyWhitelistActive = !mEnabledFontsList.IsEmpty();
+  }
+
+  // From here, gfxPlatformFontList::IsInitialized will return true,
+  // unless InitFontListForPlatform() fails and we reset it below.
+  mFontlistInitCount++;
+
+  InitializeCodepointsWithNoFonts();
+
+  // Try to initialize the cross-process shared font list if enabled by prefs,
+  // but not if we're running in Safe Mode.
+  if (StaticPrefs::gfx_e10s_font_list_shared_AtStartup() &&
+      !gfxPlatform::InSafeMode()) {
+    for (const auto& entry : mFontEntries.Values()) {
+      if (!entry) {
+        continue;
+      }
+      AutoWriteLock lock(entry->mLock);
+      entry->mShmemCharacterMap = nullptr;
+      entry->mShmemFace = nullptr;
+      entry->mFamilyName.Truncate();
+    }
+    mFontEntries.Clear();
+    mShmemCharMaps.Clear();
+    bool oldSharedList = mSharedFontList != nullptr;
+    mSharedFontList.reset(new fontlist::FontList(mFontlistInitCount));
+    InitSharedFontListForPlatform();
+    if (mSharedFontList && mSharedFontList->Initialized()) {
+      if (mLocalNameTable.Count()) {
+        SharedFontList()->SetLocalNames(mLocalNameTable);
+        mLocalNameTable.Clear();
+      }
+    } else {
+      // something went wrong, fall back to in-process list
+      gfxCriticalNote << "Failed to initialize shared font list, "
+                         "falling back to in-process list.";
+      mSharedFontList.reset(nullptr);
+    }
+    if (oldSharedList && XRE_IsParentProcess()) {
+      // notify all children of the change
+      if (NS_IsMainThread()) {
+        dom::ContentParent::NotifyUpdatedFonts(true);
+      } else {
+        NS_DispatchToMainThread(NS_NewRunnableFunction(
+            "NotifyUpdatedFonts callback",
+            [] { dom::ContentParent::NotifyUpdatedFonts(true); }));
+      }
+    }
+  }
+
+  if (!SharedFontList()) {
+    if (NS_FAILED(InitFontListForPlatform())) {
+      mFontlistInitCount = 0;
+      return false;
+    }
+    ApplyWhitelist();
+  }
+
+  // Set up mDefaultFontEntry as a "last resort" default that we can use
+  // to avoid crashing if the font list is otherwise unusable.
+  gfxFontStyle defStyle;
+  FontFamily fam = GetDefaultFontLocked(nullptr, &defStyle);
+  gfxFontEntry* fe;
+  if (fam.mShared) {
+    auto face = fam.mShared->FindFaceForStyle(SharedFontList(), defStyle);
+    fe = face ? GetOrCreateFontEntryLocked(face, fam.mShared) : nullptr;
+  } else {
+    fe = fam.mUnshared->FindFontForStyle(defStyle);
+  }
+  mDefaultFontEntry = fe;
+
+  return true;
+}
+
+void gfxPlatformFontList::InitializeCodepointsWithNoFonts() {
+  auto& first = mCodepointsWithNoFonts[FontVisibility(0)];
+  for (auto& bitset : mCodepointsWithNoFonts) {
+    if (&bitset == &first) {
+      bitset.reset();
+      bitset.SetRange(0, 0x1f);            // C0 controls
+      bitset.SetRange(0x7f, 0x9f);         // C1 controls
+      bitset.SetRange(0xE000, 0xF8FF);     // PUA
+      bitset.SetRange(0xF0000, 0x10FFFD);  // Supplementary PUA
+      bitset.SetRange(0xfdd0, 0xfdef);     // noncharacters
+      for (unsigned i = 0; i <= 0x100000; i += 0x10000) {
+        bitset.SetRange(i + 0xfffe, i + 0xffff);  // noncharacters
+      }
+      bitset.Compact();
+    } else {
+      bitset = first;
+    }
+  }
+}
+
+void gfxPlatformFontList::FontListChanged() {
+  MOZ_ASSERT(!XRE_IsParentProcess());
+  AutoLock lock(mLock);
+  InitializeCodepointsWithNoFonts();
+  if (SharedFontList()) {
+    // If we're using a shared local face-name list, this may have changed
+    // such that existing font entries held by user font sets are no longer
+    // safe to use: ensure they all get flushed.
+    RebuildLocalFonts(/*aForgetLocalFaces*/ true);
+  }
+  ForceGlobalReflowLocked(gfxPlatform::NeedsReframe::Yes);
+}
+
+void gfxPlatformFontList::GenerateFontListKey(const nsACString& aKeyName,
+                                              nsACString& aResult) {
+  aResult = aKeyName;
+  ToLowerCase(aResult);
+}
+
+// Used if a stylo thread wants to trigger InitOtherFamilyNames in the main
+// process: we can't do IPC from the stylo thread so we post this to the main
+// thread instead.
+class InitOtherFamilyNamesForStylo : public mozilla::Runnable {
+ public:
+  explicit InitOtherFamilyNamesForStylo(bool aDeferOtherFamilyNamesLoading)
+      : Runnable("gfxPlatformFontList::InitOtherFamilyNamesForStylo"),
+        mDefer(aDeferOtherFamilyNamesLoading) {}
+
+  NS_IMETHOD Run() override {
+    auto pfl = gfxPlatformFontList::PlatformFontList();
+    auto list = pfl->SharedFontList();
+    if (!list) {
+      return NS_OK;
+    }
+    bool initialized = false;
+    dom::ContentChild::GetSingleton()->SendInitOtherFamilyNames(
+        list->GetGeneration(), mDefer, &initialized);
+    pfl->mOtherFamilyNamesInitialized.compareExchange(false, initialized);
+    return NS_OK;
+  }
+
+ private:
+  bool mDefer;
+};
+
+#define OTHERNAMES_TIMEOUT 200
+
+bool gfxPlatformFontList::InitOtherFamilyNames(
+    bool aDeferOtherFamilyNamesLoading) {
+  if (mOtherFamilyNamesInitialized) {
+    return true;
+  }
+
+  if (SharedFontList() && !XRE_IsParentProcess()) {
+    if (NS_IsMainThread()) {
+      bool initialized;
+      dom::ContentChild::GetSingleton()->SendInitOtherFamilyNames(
+          SharedFontList()->GetGeneration(), aDeferOtherFamilyNamesLoading,
+          &initialized);
+      mOtherFamilyNamesInitialized.compareExchange(false, initialized);
+    } else {
+      NS_DispatchToMainThread(
+          new InitOtherFamilyNamesForStylo(aDeferOtherFamilyNamesLoading));
+    }
+    return mOtherFamilyNamesInitialized;
+  }
+
+  // If the font loader delay has been set to zero, we don't defer loading
+  // additional family names (regardless of the aDefer... parameter), as we
+  // take this to mean availability of font info is to be prioritized over
+  // potential startup perf or main-thread jank.
+  // (This is used so we can reliably run reftests that depend on localized
+  // font-family names being available.)
+  if (aDeferOtherFamilyNamesLoading &&
+      StaticPrefs::gfx_font_loader_delay_AtStartup() > 0) {
+    if (!mPendingOtherFamilyNameTask) {
+      RefPtr<mozilla::CancelableRunnable> task =
+          new InitOtherFamilyNamesRunnable();
+      mPendingOtherFamilyNameTask = task;
+      NS_DispatchToMainThreadQueue(task.forget(), EventQueuePriority::Idle);
+    }
+  } else {
+    InitOtherFamilyNamesInternal(false);
+  }
+  return mOtherFamilyNamesInitialized;
+}
+
+// time limit for loading facename lists (ms)
+#define NAMELIST_TIMEOUT 200
+
+gfxFontEntry* gfxPlatformFontList::SearchFamiliesForFaceName(
+    const nsACString& aFaceName) {
+  TimeStamp start = TimeStamp::Now();
+  bool timedOut = false;
+  // if mFirstChar is not 0, only load facenames for families
+  // that start with this character
+  char16_t firstChar = 0;
+  gfxFontEntry* lookup = nullptr;
+
+  // iterate over familes starting with the same letter
+  firstChar = ToLowerCase(aFaceName.CharAt(0));
+
+  for (const auto& entry : mFontFamilies) {
+    nsCStringHashKey::KeyType key = entry.GetKey();
+    const RefPtr<gfxFontFamily>& family = entry.GetData();
+
+    // when filtering, skip names that don't start with the filter character
+    if (firstChar && ToLowerCase(key.CharAt(0)) != firstChar) {
+      continue;
+    }
+
+    family->ReadFaceNames(this, NeedFullnamePostscriptNames());
+
+    TimeDuration elapsed = TimeStamp::Now() - start;
+    if (elapsed.ToMilliseconds() > NAMELIST_TIMEOUT) {
+      timedOut = true;
+      break;
+    }
+  }
+
+  lookup = FindFaceName(aFaceName);
+
+  TimeStamp end = TimeStamp::Now();
+  Telemetry::AccumulateTimeDelta(Telemetry::FONTLIST_INITFACENAMELISTS, start,
+                                 end);
+  if (LOG_FONTINIT_ENABLED()) {
+    TimeDuration elapsed = end - start;
+    LOG_FONTINIT(("(fontinit) SearchFamiliesForFaceName took %8.2f ms %s %s",
+                  elapsed.ToMilliseconds(), (lookup ? "found name" : ""),
+                  (timedOut ? "timeout" : "")));
+  }
+
+  return lookup;
+}
+
+gfxFontEntry* gfxPlatformFontList::FindFaceName(const nsACString& aFaceName) {
+  gfxFontEntry* lookup;
+
+  // lookup in name lookup tables, return null if not found
+  if (mExtraNames &&
+      ((lookup = mExtraNames->mPostscriptNames.GetWeak(aFaceName)) ||
+       (lookup = mExtraNames->mFullnames.GetWeak(aFaceName)))) {
+    return lookup;
+  }
+
+  return nullptr;
+}
+
+gfxFontEntry* gfxPlatformFontList::LookupInFaceNameLists(
+    const nsACString& aFaceName) {
+  gfxFontEntry* lookup = nullptr;
+
+  // initialize facename lookup tables if needed
+  // note: this can terminate early or time out, in which case
+  //       mFaceNameListsInitialized remains false
+  if (!mFaceNameListsInitialized) {
+    lookup = SearchFamiliesForFaceName(aFaceName);
+    if (lookup) {
+      return lookup;
+    }
+  }
+
+  // lookup in name lookup tables, return null if not found
+  if (!(lookup = FindFaceName(aFaceName))) {
+    // names not completely initialized, so keep track of lookup misses
+    if (!mFaceNameListsInitialized) {
+      if (!mFaceNamesMissed) {
+        mFaceNamesMissed = MakeUnique<nsTHashSet<nsCString>>(2);
+      }
+      mFaceNamesMissed->Insert(aFaceName);
+    }
+  }
+
+  return lookup;
+}
+
+gfxFontEntry* gfxPlatformFontList::LookupInSharedFaceNameList(
+    nsPresContext* aPresContext, const nsACString& aFaceName,
+    WeightRange aWeightForEntry, StretchRange aStretchForEntry,
+    SlantStyleRange aStyleForEntry) {
+  nsAutoCString keyName(aFaceName);
+  ToLowerCase(keyName);
+  fontlist::FontList* list = SharedFontList();
+  fontlist::Family* family = nullptr;
+  fontlist::Face* face = nullptr;
+  if (list->NumLocalFaces()) {
+    fontlist::LocalFaceRec* rec = list->FindLocalFace(keyName);
+    if (rec) {
+      auto* families = list->Families();
+      if (families) {
+        family = &families[rec->mFamilyIndex];
+        face = static_cast<fontlist::Face*>(
+            family->Faces(list)[rec->mFaceIndex].ToPtr(list));
+      }
+    }
+  } else {
+    list->SearchForLocalFace(keyName, &family, &face);
+  }
+  if (!face || !family) {
+    return nullptr;
+  }
+  FontVisibility level =
+      aPresContext ? aPresContext->GetFontVisibility() : FontVisibility::User;
+  if (!IsVisibleToCSS(*family, level)) {
+    if (aPresContext) {
+      aPresContext->ReportBlockedFontFamily(*family);
+    }
+    return nullptr;
+  }
+  gfxFontEntry* fe = CreateFontEntry(face, family);
+  if (fe) {
+    fe->mIsLocalUserFont = true;
+    fe->mWeightRange = aWeightForEntry;
+    fe->mStretchRange = aStretchForEntry;
+    fe->mStyleRange = aStyleForEntry;
+  }
+  return fe;
+}
+
+void gfxPlatformFontList::LoadBadUnderlineList() {
+  gfxFontUtils::GetPrefsFontList("font.blacklist.underline_offset",
+                                 mBadUnderlineFamilyNames);
+  for (auto& fam : mBadUnderlineFamilyNames) {
+    ToLowerCase(fam);
+  }
+  mBadUnderlineFamilyNames.Compact();
+  mBadUnderlineFamilyNames.Sort();
+}
+
+void gfxPlatformFontList::UpdateFontList(bool aFullRebuild) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (aFullRebuild) {
+    InitFontList();
+    AutoLock lock(mLock);
+    RebuildLocalFonts();
+  } else {
+    // The font list isn't being fully rebuilt, we're just being notified that
+    // character maps have been updated and so font fallback needs to be re-
+    // done. We only care about this if we have previously encountered a
+    // fallback that required cmaps that were not yet available, and so we
+    // asked for the async cmap loader to run.
+    AutoLock lock(mLock);
+    if (mStartedLoadingCmapsFrom != 0xffffffffu) {
+      InitializeCodepointsWithNoFonts();
+      mStartedLoadingCmapsFrom = 0xffffffffu;
+      ForceGlobalReflowLocked(gfxPlatform::NeedsReframe::No);
+    }
+  }
+}
+
+bool gfxPlatformFontList::IsVisibleToCSS(const gfxFontFamily& aFamily,
+                                         FontVisibility aVisibility) const {
+  return aFamily.Visibility() <= aVisibility || IsFontFamilyWhitelistActive();
+}
+
+bool gfxPlatformFontList::IsVisibleToCSS(const fontlist::Family& aFamily,
+                                         FontVisibility aVisibility) const {
+  return aFamily.Visibility() <= aVisibility || IsFontFamilyWhitelistActive();
+}
+
+void gfxPlatformFontList::GetFontList(nsAtom* aLangGroup,
+                                      const nsACString& aGenericFamily,
+                                      nsTArray<nsString>& aListOfFonts) {
+  AutoLock lock(mLock);
+
+  if (SharedFontList()) {
+    fontlist::FontList* list = SharedFontList();
+    const fontlist::Family* families = list->Families();
+    if (families) {
+      for (uint32_t i = 0; i < list->NumFamilies(); i++) {
+        auto& f = families[i];
+        if (!IsVisibleToCSS(f, FontVisibility::User) || f.IsAltLocaleFamily()) {
+          continue;
+        }
+        // XXX TODO: filter families for aGenericFamily, if supported by
+        // platform
+        aListOfFonts.AppendElement(
+            NS_ConvertUTF8toUTF16(list->LocalizedFamilyName(&f)));
+      }
+    }
+    return;
+  }
+
+  for (const RefPtr<gfxFontFamily>& family : mFontFamilies.Values()) {
+    if (!IsVisibleToCSS(*family, FontVisibility::User)) {
+      continue;
+    }
+    if (family->FilterForFontList(aLangGroup, aGenericFamily)) {
+      nsAutoCString localizedFamilyName;
+      family->LocalizedName(localizedFamilyName);
+      aListOfFonts.AppendElement(NS_ConvertUTF8toUTF16(localizedFamilyName));
+    }
+  }
+
+  aListOfFonts.Sort();
+  aListOfFonts.Compact();
+}
+
+void gfxPlatformFontList::GetFontFamilyList(
+    nsTArray<RefPtr<gfxFontFamily>>& aFamilyArray) {
+  AutoLock lock(mLock);
+  MOZ_ASSERT(aFamilyArray.IsEmpty());
+  // This doesn't use ToArray, because the caller passes an AutoTArray.
+  aFamilyArray.SetCapacity(mFontFamilies.Count());
+  for (const auto& family : mFontFamilies.Values()) {
+    aFamilyArray.AppendElement(family);
+  }
+}
+
+already_AddRefed<gfxFont> gfxPlatformFontList::SystemFindFontForChar(
+    nsPresContext* aPresContext, uint32_t aCh, uint32_t aNextCh,
+    Script aRunScript, eFontPresentation aPresentation,
+    const gfxFontStyle* aStyle, FontVisibility* aVisibility) {
+  AutoLock lock(mLock);
+  FontVisibility level =
+      aPresContext ? aPresContext->GetFontVisibility() : FontVisibility::User;
+  MOZ_ASSERT(!mCodepointsWithNoFonts[level].test(aCh),
+             "don't call for codepoints already known to be unsupported");
+
+  // Try to short-circuit font fallback for U+FFFD, used to represent
+  // encoding errors: just use cached family from last time U+FFFD was seen.
+  // This helps speed up pages with lots of encoding errors, binary-as-text,
+  // etc.
+  if (aCh == 0xFFFD) {
+    gfxFontEntry* fontEntry = nullptr;
+    auto& fallbackFamily = mReplacementCharFallbackFamily[level];
+    if (fallbackFamily.mShared) {
+      fontlist::Face* face =
+          fallbackFamily.mShared->FindFaceForStyle(SharedFontList(), *aStyle);
+      if (face) {
+        fontEntry = GetOrCreateFontEntryLocked(face, fallbackFamily.mShared);
+        *aVisibility = fallbackFamily.mShared->Visibility();
+      }
+    } else if (fallbackFamily.mUnshared) {
+      fontEntry = fallbackFamily.mUnshared->FindFontForStyle(*aStyle);
+      *aVisibility = fallbackFamily.mUnshared->Visibility();
+    }
+
+    // this should never fail, as we must have found U+FFFD in order to set
+    // mReplacementCharFallbackFamily[...] at all, but better play it safe
+    if (fontEntry && fontEntry->HasCharacter(aCh)) {
+      return fontEntry->FindOrMakeFont(aStyle);
+    }
+  }
+
+  TimeStamp start = TimeStamp::Now();
+
+  // search commonly available fonts
+  bool common = true;
+  FontFamily fallbackFamily;
+  RefPtr<gfxFont> candidate =
+      CommonFontFallback(aPresContext, aCh, aNextCh, aRunScript, aPresentation,
+                         aStyle, fallbackFamily);
+  RefPtr<gfxFont> font;
+  if (candidate) {
+    if (aPresentation == eFontPresentation::Any) {
+      font = std::move(candidate);
+    } else {
+      bool hasColorGlyph = candidate->HasColorGlyphFor(aCh, aNextCh);
+      if (hasColorGlyph == PrefersColor(aPresentation)) {
+        font = std::move(candidate);
+      }
+    }
+  }
+
+  // If we didn't find a common font, or it was not the preferred type (color
+  // or monochrome), do system-wide fallback (except for specials).
+  uint32_t cmapCount = 0;
+  if (!font) {
+    common = false;
+    font = GlobalFontFallback(aPresContext, aCh, aNextCh, aRunScript,
+                              aPresentation, aStyle, cmapCount, fallbackFamily);
+    // If the font we found doesn't match the requested type, and we also found
+    // a candidate above, prefer that one.
+    if (font && aPresentation != eFontPresentation::Any && candidate) {
+      bool hasColorGlyph = font->HasColorGlyphFor(aCh, aNextCh);
+      if (hasColorGlyph != PrefersColor(aPresentation)) {
+        font = std::move(candidate);
+      }
+    }
+  }
+  TimeDuration elapsed = TimeStamp::Now() - start;
+
+  LogModule* log = gfxPlatform::GetLog(eGfxLog_textrun);
+
+  if (MOZ_UNLIKELY(MOZ_LOG_TEST(log, LogLevel::Warning))) {
+    Script script = intl::UnicodeProperties::GetScriptCode(aCh);
+    MOZ_LOG(log, LogLevel::Warning,
+            ("(textrun-systemfallback-%s) char: u+%6.6x "
+             "script: %d match: [%s]"
+             " time: %dus cmaps: %d\n",
+             (common ? "common" : "global"), aCh, static_cast<int>(script),
+             (font ? font->GetFontEntry()->Name().get() : "<none>"),
+             int32_t(elapsed.ToMicroseconds()), cmapCount));
+  }
+
+  // no match? add to set of non-matching codepoints
+  if (!font) {
+    mCodepointsWithNoFonts[level].set(aCh);
+  } else {
+    *aVisibility = fallbackFamily.mShared
+                       ? fallbackFamily.mShared->Visibility()
+                       : fallbackFamily.mUnshared->Visibility();
+    if (aCh == 0xFFFD) {
+      mReplacementCharFallbackFamily[level] = fallbackFamily;
+    }
+  }
+
+  // track system fallback time
+  static bool first = true;
+  int32_t intElapsed =
+      int32_t(first ? elapsed.ToMilliseconds() : elapsed.ToMicroseconds());
+  Telemetry::Accumulate((first ? Telemetry::SYSTEM_FONT_FALLBACK_FIRST
+                               : Telemetry::SYSTEM_FONT_FALLBACK),
+                        intElapsed);
+  first = false;
+
+  // track the script for which fallback occurred (incremented one make it
+  // 1-based)
+  Telemetry::Accumulate(Telemetry::SYSTEM_FONT_FALLBACK_SCRIPT,
+                        int(aRunScript) + 1);
+
+  return font.forget();
+}
+
+#define NUM_FALLBACK_FONTS 8
+
+already_AddRefed<gfxFont> gfxPlatformFontList::CommonFontFallback(
+    nsPresContext* aPresContext, uint32_t aCh, uint32_t aNextCh,
+    Script aRunScript, eFontPresentation aPresentation,
+    const gfxFontStyle* aMatchStyle, FontFamily& aMatchedFamily) {
+  AutoTArray<const char*, NUM_FALLBACK_FONTS> defaultFallbacks;
+  gfxPlatform::GetPlatform()->GetCommonFallbackFonts(
+      aCh, aRunScript, aPresentation, defaultFallbacks);
+  GlobalFontMatch data(aCh, aNextCh, *aMatchStyle, aPresentation);
+  FontVisibility level =
+      aPresContext ? aPresContext->GetFontVisibility() : FontVisibility::User;
+
+  // If a color-emoji presentation is requested, we will check any font found
+  // to see if it can provide this; if not, we'll remember it as a possible
+  // candidate but search the remainder of the list for a better choice.
+  RefPtr<gfxFont> candidateFont;
+  FontFamily candidateFamily;
+  auto check = [&](gfxFontEntry* aFontEntry,
+                   FontFamily aFamily) -> already_AddRefed<gfxFont> {
+    RefPtr<gfxFont> font = aFontEntry->FindOrMakeFont(aMatchStyle);
+    if (aPresentation < eFontPresentation::EmojiDefault ||
+        font->HasColorGlyphFor(aCh, aNextCh)) {
+      aMatchedFamily = aFamily;
+      return font.forget();
+    }
+    // We want a color glyph but this font only has monochrome; remember it
+    // (unless we already have a candidate) but continue to search.
+    if (!candidateFont) {
+      candidateFont = std::move(font);
+      candidateFamily = aFamily;
+    }
+    return nullptr;
+  };
+
+  if (SharedFontList()) {
+    for (const auto name : defaultFallbacks) {
+      fontlist::Family* family =
+          FindSharedFamily(aPresContext, nsDependentCString(name));
+      if (!family || !IsVisibleToCSS(*family, level)) {
+        continue;
+      }
+      // XXX(jfkthame) Should we fire the async cmap-loader here, or let it
+      // always do a potential sync initialization of the family?
+      family->SearchAllFontsForChar(SharedFontList(), &data);
+      if (data.mBestMatch) {
+        RefPtr<gfxFont> font = check(data.mBestMatch, FontFamily(family));
+        if (font) {
+          return font.forget();
+        }
+      }
+    }
+  } else {
+    for (const auto name : defaultFallbacks) {
+      gfxFontFamily* fallback =
+          FindFamilyByCanonicalName(nsDependentCString(name));
+      if (!fallback || !IsVisibleToCSS(*fallback, level)) {
+        continue;
+      }
+      fallback->FindFontForChar(&data);
+      if (data.mBestMatch) {
+        RefPtr<gfxFont> font = check(data.mBestMatch, FontFamily(fallback));
+        if (font) {
+          return font.forget();
+        }
+      }
+    }
+  }
+
+  // If we had a candidate that supports the character, but doesn't have the
+  // desired emoji-style glyph, we'll return it anyhow as nothing better was
+  // found.
+  if (candidateFont) {
+    aMatchedFamily = candidateFamily;
+    return candidateFont.forget();
+  }
+
+  return nullptr;
+}
+
+already_AddRefed<gfxFont> gfxPlatformFontList::GlobalFontFallback(
+    nsPresContext* aPresContext, uint32_t aCh, uint32_t aNextCh,
+    Script aRunScript, eFontPresentation aPresentation,
+    const gfxFontStyle* aMatchStyle, uint32_t& aCmapCount,
+    FontFamily& aMatchedFamily) {
+  bool useCmaps = IsFontFamilyWhitelistActive() ||
+                  gfxPlatform::GetPlatform()->UseCmapsDuringSystemFallback();
+  FontVisibility level =
+      aPresContext ? aPresContext->GetFontVisibility() : FontVisibility::User;
+  if (!useCmaps) {
+    // Allow platform-specific fallback code to try and find a usable font
+    gfxFontEntry* fe = PlatformGlobalFontFallback(aPresContext, aCh, aRunScript,
+                                                  aMatchStyle, aMatchedFamily);
+    if (fe) {
+      if (aMatchedFamily.mShared) {
+        if (IsVisibleToCSS(*aMatchedFamily.mShared, level)) {
+          RefPtr<gfxFont> font = fe->FindOrMakeFont(aMatchStyle);
+          if (font) {
+            if (aPresentation == eFontPresentation::Any) {
+              return font.forget();
+            }
+            bool hasColorGlyph = font->HasColorGlyphFor(aCh, aNextCh);
+            if (hasColorGlyph == PrefersColor(aPresentation)) {
+              return font.forget();
+            }
+          }
+        }
+      } else {
+        if (IsVisibleToCSS(*aMatchedFamily.mUnshared, level)) {
+          RefPtr<gfxFont> font = fe->FindOrMakeFont(aMatchStyle);
+          if (font) {
+            if (aPresentation == eFontPresentation::Any) {
+              return font.forget();
+            }
+            bool hasColorGlyph = font->HasColorGlyphFor(aCh, aNextCh);
+            if (hasColorGlyph == PrefersColor(aPresentation)) {
+              return font.forget();
+            }
+          }
+        }
+      }
+    }
+  }
+
+  // otherwise, try to find it among local fonts
+  GlobalFontMatch data(aCh, aNextCh, *aMatchStyle, aPresentation);
+  if (SharedFontList()) {
+    fontlist::Family* families = SharedFontList()->Families();
+    if (families) {
+      for (uint32_t i = 0; i < SharedFontList()->NumFamilies(); i++) {
+        fontlist::Family& family = families[i];
+        if (!IsVisibleToCSS(family, level)) {
+          continue;
+        }
+        if (!family.IsFullyInitialized() &&
+            StaticPrefs::gfx_font_rendering_fallback_async() &&
+            !XRE_IsParentProcess()) {
+          // Start loading all the missing charmaps; but this is async,
+          // so for now we just continue, ignoring this family.
+          StartCmapLoadingFromFamily(i);
+        } else {
+          family.SearchAllFontsForChar(SharedFontList(), &data);
+          if (data.mMatchDistance == 0.0) {
+            // no better style match is possible, so stop searching
+            break;
+          }
+        }
+      }
+      if (data.mBestMatch) {
+        aMatchedFamily = FontFamily(data.mMatchedSharedFamily);
+        return data.mBestMatch->FindOrMakeFont(aMatchStyle);
+      }
+    }
+  } else {
+    // iterate over all font families to find a font that support the
+    // character
+    for (const RefPtr<gfxFontFamily>& family : mFontFamilies.Values()) {
+      if (!IsVisibleToCSS(*family, level)) {
+        continue;
+      }
+      // evaluate all fonts in this family for a match
+      family->FindFontForChar(&data);
+      if (data.mMatchDistance == 0.0) {
+        // no better style match is possible, so stop searching
+        break;
+      }
+    }
+
+    aCmapCount = data.mCmapsTested;
+    if (data.mBestMatch) {
+      aMatchedFamily = FontFamily(data.mMatchedFamily);
+      return data.mBestMatch->FindOrMakeFont(aMatchStyle);
+    }
+  }
+
+  return nullptr;
+}
+
+class StartCmapLoadingRunnable : public mozilla::Runnable {
+ public:
+  explicit StartCmapLoadingRunnable(uint32_t aStartIndex)
+      : Runnable("gfxPlatformFontList::StartCmapLoadingRunnable"),
+        mStartIndex(aStartIndex) {}
+
+  NS_IMETHOD Run() override {
+    auto* pfl = gfxPlatformFontList::PlatformFontList();
+    auto* list = pfl->SharedFontList();
+    if (!list) {
+      return NS_OK;
+    }
+    if (mStartIndex >= list->NumFamilies()) {
+      return NS_OK;
+    }
+    if (XRE_IsParentProcess()) {
+      pfl->StartCmapLoading(list->GetGeneration(), mStartIndex);
+    } else {
+      dom::ContentChild::GetSingleton()->SendStartCmapLoading(
+          list->GetGeneration(), mStartIndex);
+    }
+    return NS_OK;
+  }
+
+ private:
+  uint32_t mStartIndex;
+};
+
+void gfxPlatformFontList::StartCmapLoadingFromFamily(uint32_t aStartIndex) {
+  if (aStartIndex > mStartedLoadingCmapsFrom) {
+    // We already initiated cmap-loading from somewhere earlier in the list;
+    // no need to do it again here.
+    return;
+  }
+  mStartedLoadingCmapsFrom = aStartIndex;
+
+  // If we're already on the main thread, don't bother dispatching a runnable
+  // here to kick off the loading process, just do it directly.
+  if (NS_IsMainThread()) {
+    auto* list = SharedFontList();
+    if (XRE_IsParentProcess()) {
+      StartCmapLoading(list->GetGeneration(), aStartIndex);
+    } else {
+      dom::ContentChild::GetSingleton()->SendStartCmapLoading(
+          list->GetGeneration(), aStartIndex);
+    }
+  } else {
+    NS_DispatchToMainThread(new StartCmapLoadingRunnable(aStartIndex));
+  }
+}
+
+class LoadCmapsRunnable : public CancelableRunnable {
+  class WillShutdownObserver : public nsIObserver {
+   public:
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIOBSERVER
+
+    explicit WillShutdownObserver(LoadCmapsRunnable* aRunnable)
+        : mRunnable(aRunnable) {}
+
+    void Remove() {
+      nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+      if (obs) {
+        obs->RemoveObserver(this, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID);
+      }
+      mRunnable = nullptr;
+    }
+
+   protected:
+    virtual ~WillShutdownObserver() = default;
+
+    LoadCmapsRunnable* mRunnable;
+  };
+
+ public:
+  explicit LoadCmapsRunnable(uint32_t aGeneration, uint32_t aFamilyIndex)
+      : CancelableRunnable("gfxPlatformFontList::LoadCmapsRunnable"),
+        mGeneration(aGeneration),
+        mStartIndex(aFamilyIndex),
+        mIndex(aFamilyIndex) {
+    nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+    if (obs) {
+      mObserver = new WillShutdownObserver(this);
+      obs->AddObserver(mObserver, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID, false);
+    }
+  }
+
+  virtual ~LoadCmapsRunnable() {
+    if (mObserver) {
+      mObserver->Remove();
+    }
+  }
+
+  // Reset the current family index, if the value passed is earlier than our
+  // original starting position. We don't "reset" if it would move the current
+  // position forward, or back into the already-scanned range.
+  // We could optimize further by remembering the current position reached,
+  // and then skipping ahead from the original start, but it doesn't seem worth
+  // extra complexity for a task that usually only happens once, and already-
+  // processed families will be skipped pretty quickly in Run() anyhow.
+  void MaybeResetIndex(uint32_t aFamilyIndex) {
+    if (aFamilyIndex < mStartIndex) {
+      mStartIndex = aFamilyIndex;
+      mIndex = aFamilyIndex;
+    }
+  }
+
+  nsresult Cancel() override {
+    mIsCanceled = true;
+    return NS_OK;
+  }
+
+  NS_IMETHOD Run() override {
+    if (mIsCanceled) {
+      return NS_OK;
+    }
+    auto* pfl = gfxPlatformFontList::PlatformFontList();
+    auto* list = pfl->SharedFontList();
+    MOZ_ASSERT(list);
+    if (!list) {
+      return NS_OK;
+    }
+    if (mGeneration != list->GetGeneration()) {
+      return NS_OK;
+    }
+    uint32_t numFamilies = list->NumFamilies();
+    if (mIndex >= numFamilies) {
+      return NS_OK;
+    }
+    auto* families = list->Families();
+    // Skip any families that are already initialized.
+    while (mIndex < numFamilies && families[mIndex].IsFullyInitialized()) {
+      ++mIndex;
+    }
+    // Fully process one family, and advance index.
+    if (mIndex < numFamilies) {
+      Unused << pfl->InitializeFamily(&families[mIndex], true);
+      ++mIndex;
+    }
+    // If there are more families to initialize, post ourselves back to the
+    // idle queue to handle the next one; otherwise we're finished and we need
+    // to notify content processes to update their rendering.
+    if (mIndex < numFamilies) {
+      RefPtr<CancelableRunnable> task = this;
+      NS_DispatchToMainThreadQueue(task.forget(), EventQueuePriority::Idle);
+    } else {
+      pfl->Lock();
+      pfl->CancelLoadCmapsTask();
+      pfl->InitializeCodepointsWithNoFonts();
+      dom::ContentParent::NotifyUpdatedFonts(false);
+      pfl->Unlock();
+    }
+    return NS_OK;
+  }
+
+ private:
+  uint32_t mGeneration;
+  uint32_t mStartIndex;
+  uint32_t mIndex;
+  bool mIsCanceled = false;
+
+  RefPtr<WillShutdownObserver> mObserver;
+};
+
+NS_IMPL_ISUPPORTS(LoadCmapsRunnable::WillShutdownObserver, nsIObserver)
+
+NS_IMETHODIMP
+LoadCmapsRunnable::WillShutdownObserver::Observe(nsISupports* aSubject,
+                                                 const char* aTopic,
+                                                 const char16_t* aData) {
+  if (!nsCRT::strcmp(aTopic, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID)) {
+    if (mRunnable) {
+      mRunnable->Cancel();
+    }
+  } else {
+    MOZ_ASSERT_UNREACHABLE("unexpected notification topic");
+  }
+  return NS_OK;
+}
+
+void gfxPlatformFontList::StartCmapLoading(uint32_t aGeneration,
+                                           uint32_t aStartIndex) {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  if (aGeneration != SharedFontList()->GetGeneration()) {
+    return;
+  }
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return;
+  }
+  if (mLoadCmapsRunnable) {
+    // We already have a runnable; just make sure it covers the full range of
+    // families needed.
+    static_cast<LoadCmapsRunnable*>(mLoadCmapsRunnable.get())
+        ->MaybeResetIndex(aStartIndex);
+    return;
+  }
+  mLoadCmapsRunnable = new LoadCmapsRunnable(aGeneration, aStartIndex);
+  RefPtr<CancelableRunnable> task = mLoadCmapsRunnable;
+  NS_DispatchToMainThreadQueue(task.forget(), EventQueuePriority::Idle);
+}
+
+gfxFontFamily* gfxPlatformFontList::CheckFamily(gfxFontFamily* aFamily) {
+  if (aFamily && !aFamily->HasStyles()) {
+    aFamily->FindStyleVariations();
+  }
+
+  if (aFamily && aFamily->FontListLength() == 0) {
+    // Failed to load any faces for this family, so discard it.
+    nsAutoCString key;
+    GenerateFontListKey(aFamily->Name(), key);
+    mFontFamilies.Remove(key);
+    return nullptr;
+  }
+
+  return aFamily;
+}
+
+bool gfxPlatformFontList::FindAndAddFamiliesLocked(
+    nsPresContext* aPresContext, StyleGenericFontFamily aGeneric,
+    const nsACString& aFamily, nsTArray<FamilyAndGeneric>* aOutput,
+    FindFamiliesFlags aFlags, gfxFontStyle* aStyle, nsAtom* aLanguage,
+    gfxFloat aDevToCssSize) {
+  nsAutoCString key;
+  GenerateFontListKey(aFamily, key);
+
+  bool allowHidden = bool(aFlags & FindFamiliesFlags::eSearchHiddenFamilies);
+  FontVisibility visibilityLevel =
+      aPresContext ? aPresContext->GetFontVisibility() : FontVisibility::User;
+
+  if (SharedFontList()) {
+    fontlist::Family* family = SharedFontList()->FindFamily(key);
+    // If not found, and other family names have not yet been initialized,
+    // initialize the rest of the list and try again. This is done lazily
+    // since reading name table entries is expensive.
+    // Although ASCII localized family names are possible they don't occur
+    // in practice, so avoid pulling in names at startup.
+    if (!family && !mOtherFamilyNamesInitialized) {
+      bool triggerLoading = true;
+      bool mayDefer =
+          !(aFlags & FindFamiliesFlags::eForceOtherFamilyNamesLoading);
+      if (IsAscii(key)) {
+        // If `key` is an ASCII name, only trigger loading if it includes a
+        // space, and the "base" name (up to the last space) exists as a known
+        // family, so that this might be a legacy styled-family name.
+        const char* data = key.BeginReading();
+        int32_t index = key.Length();
+        while (--index > 0) {
+          if (data[index] == ' ') {
+            break;
+          }
+        }
+        if (index <= 0 ||
+            !SharedFontList()->FindFamily(nsAutoCString(key.get(), index))) {
+          triggerLoading = false;
+        }
+      }
+      if (triggerLoading) {
+        if (InitOtherFamilyNames(mayDefer)) {
+          family = SharedFontList()->FindFamily(key);
+        }
+      }
+      if (!family && !mOtherFamilyNamesInitialized &&
+          !(aFlags & FindFamiliesFlags::eNoAddToNamesMissedWhenSearching)) {
+        AddToMissedNames(key);
+      }
+    }
+    // Check whether the family we found is actually allowed to be looked up,
+    // according to current font-visibility prefs.
+    if (family) {
+      bool visible = IsVisibleToCSS(*family, visibilityLevel);
+      if (visible || (allowHidden && family->IsHidden())) {
+        aOutput->AppendElement(FamilyAndGeneric(family, aGeneric));
+        return true;
+      }
+      if (aPresContext) {
+        aPresContext->ReportBlockedFontFamily(*family);
+      }
+    }
+    return false;
+  }
+
+  NS_ASSERTION(mFontFamilies.Count() != 0,
+               "system font list was not initialized correctly");
+
+  auto isBlockedByVisibilityLevel = [=](gfxFontFamily* aFamily) -> bool {
+    bool visible = IsVisibleToCSS(*aFamily, visibilityLevel);
+    if (visible || (allowHidden && aFamily->IsHidden())) {
+      return false;
+    }
+    if (aPresContext) {
+      aPresContext->ReportBlockedFontFamily(*aFamily);
+    }
+    return true;
+  };
+
+  // lookup in canonical (i.e. English) family name list
+  gfxFontFamily* familyEntry = mFontFamilies.GetWeak(key);
+  if (familyEntry) {
+    if (isBlockedByVisibilityLevel(familyEntry)) {
+      return false;
+    }
+  }
+
+  // if not found, lookup in other family names list (mostly localized names)
+  if (!familyEntry) {
+    familyEntry = mOtherFamilyNames.GetWeak(key);
+  }
+  if (familyEntry) {
+    if (isBlockedByVisibilityLevel(familyEntry)) {
+      return false;
+    }
+  }
+
+  // if still not found and other family names not yet fully initialized,
+  // initialize the rest of the list and try again.  this is done lazily
+  // since reading name table entries is expensive.
+  // although ASCII localized family names are possible they don't occur
+  // in practice so avoid pulling in names at startup
+  if (!familyEntry && !mOtherFamilyNamesInitialized && !IsAscii(aFamily)) {
+    InitOtherFamilyNames(
+        !(aFlags & FindFamiliesFlags::eForceOtherFamilyNamesLoading));
+    familyEntry = mOtherFamilyNames.GetWeak(key);
+    if (!familyEntry && !mOtherFamilyNamesInitialized &&
+        !(aFlags & FindFamiliesFlags::eNoAddToNamesMissedWhenSearching)) {
+      // localized family names load timed out, add name to list of
+      // names to check after localized names are loaded
+      AddToMissedNames(key);
+    }
+    if (familyEntry) {
+      if (isBlockedByVisibilityLevel(familyEntry)) {
+        return false;
+      }
+    }
+  }
+
+  familyEntry = CheckFamily(familyEntry);
+
+  // If we failed to find the requested family, check for a space in the
+  // name; if found, and if the "base" name (up to the last space) exists
+  // as a family, then this might be a legacy GDI-style family name for
+  // an additional weight/width. Try searching the faces of the base family
+  // and create any corresponding legacy families.
+  if (!familyEntry &&
+      !(aFlags & FindFamiliesFlags::eNoSearchForLegacyFamilyNames)) {
+    // We don't have nsAString::RFindChar, so look for a space manually
+    const char* data = aFamily.BeginReading();
+    int32_t index = aFamily.Length();
+    while (--index > 0) {
+      if (data[index] == ' ') {
+        break;
+      }
+    }
+    if (index > 0) {
+      gfxFontFamily* base =
+          FindUnsharedFamily(aPresContext, Substring(aFamily, 0, index),
+                             FindFamiliesFlags::eNoSearchForLegacyFamilyNames);
+      // If we found the "base" family name, and if it has members with
+      // legacy names, this will add corresponding font-family entries to
+      // the mOtherFamilyNames list; then retry the legacy-family search.
+      if (base && base->CheckForLegacyFamilyNames(this)) {
+        familyEntry = mOtherFamilyNames.GetWeak(key);
+      }
+      if (familyEntry) {
+        if (isBlockedByVisibilityLevel(familyEntry)) {
+          return false;
+        }
+      }
+    }
+  }
+
+  if (familyEntry) {
+    aOutput->AppendElement(FamilyAndGeneric(familyEntry, aGeneric));
+    return true;
+  }
+
+  return false;
+}
+
+void gfxPlatformFontList::AddToMissedNames(const nsCString& aKey) {
+  if (!mOtherNamesMissed) {
+    mOtherNamesMissed = MakeUnique<nsTHashSet<nsCString>>(2);
+  }
+  mOtherNamesMissed->Insert(aKey);
+}
+
+fontlist::Family* gfxPlatformFontList::FindSharedFamily(
+    nsPresContext* aPresContext, const nsACString& aFamily,
+    FindFamiliesFlags aFlags, gfxFontStyle* aStyle, nsAtom* aLanguage,
+    gfxFloat aDevToCss) {
+  if (!SharedFontList()) {
+    return nullptr;
+  }
+  AutoTArray<FamilyAndGeneric, 1> families;
+  if (!FindAndAddFamiliesLocked(aPresContext, StyleGenericFontFamily::None,
+                                aFamily, &families, aFlags, aStyle, aLanguage,
+                                aDevToCss) ||
+      !families[0].mFamily.mShared) {
+    return nullptr;
+  }
+  fontlist::Family* family = families[0].mFamily.mShared;
+  if (!family->IsInitialized()) {
+    if (!InitializeFamily(family)) {
+      return nullptr;
+    }
+  }
+  return family;
+}
+
+class InitializeFamilyRunnable : public mozilla::Runnable {
+ public:
+  explicit InitializeFamilyRunnable(uint32_t aFamilyIndex, bool aLoadCmaps)
+      : Runnable("gfxPlatformFontList::InitializeFamilyRunnable"),
+        mIndex(aFamilyIndex),
+        mLoadCmaps(aLoadCmaps) {}
+
+  NS_IMETHOD Run() override {
+    auto list = gfxPlatformFontList::PlatformFontList()->SharedFontList();
+    if (!list) {
+      return NS_OK;
+    }
+    if (mIndex >= list->NumFamilies()) {
+      // Out of range? Maybe the list got reinitialized since this request
+      // was posted - just ignore it.
+      return NS_OK;
+    }
+    dom::ContentChild::GetSingleton()->SendInitializeFamily(
+        list->GetGeneration(), mIndex, mLoadCmaps);
+    return NS_OK;
+  }
+
+ private:
+  uint32_t mIndex;
+  bool mLoadCmaps;
+};
+
+bool gfxPlatformFontList::InitializeFamily(fontlist::Family* aFamily,
+                                           bool aLoadCmaps) {
+  MOZ_ASSERT(SharedFontList());
+  auto list = SharedFontList();
+  if (!XRE_IsParentProcess()) {
+    auto* families = list->Families();
+    if (!families) {
+      return false;
+    }
+    uint32_t index = aFamily - families;
+    if (index >= list->NumFamilies()) {
+      return false;
+    }
+    if (NS_IsMainThread()) {
+      dom::ContentChild::GetSingleton()->SendInitializeFamily(
+          list->GetGeneration(), index, aLoadCmaps);
+    } else {
+      NS_DispatchToMainThread(new InitializeFamilyRunnable(index, aLoadCmaps));
+    }
+    return aFamily->IsInitialized();
+  }
+
+  if (!aFamily->IsInitialized()) {
+    // The usual case: we're being asked to populate the face list.
+    AutoTArray<fontlist::Face::InitData, 16> faceList;
+    GetFacesInitDataForFamily(aFamily, faceList, aLoadCmaps);
+    aFamily->AddFaces(list, faceList);
+  } else {
+    // The family's face list was already initialized, but if aLoadCmaps is
+    // true we also want to eagerly load character maps. This is used when a
+    // child process is doing SearchAllFontsForChar, to have the parent load
+    // all the cmaps at once and reduce IPC traffic (and content-process file
+    // access overhead, which is crippling for DirectWrite on Windows).
+    if (aLoadCmaps) {
+      auto* faces = aFamily->Faces(list);
+      if (faces) {
+        for (size_t i = 0; i < aFamily->NumFaces(); i++) {
+          auto* face = static_cast<fontlist::Face*>(faces[i].ToPtr(list));
+          if (face && face->mCharacterMap.IsNull()) {
+            // We don't want to cache this font entry, as the parent will most
+            // likely never use it again; it's just to populate the charmap for
+            // the benefit of the child process.
+            RefPtr<gfxFontEntry> fe = CreateFontEntry(face, aFamily);
+            if (fe) {
+              fe->ReadCMAP();
+            }
+          }
+        }
+      }
+    }
+  }
+
+  if (aLoadCmaps && aFamily->IsInitialized()) {
+    aFamily->SetupFamilyCharMap(list);
+  }
+
+  return aFamily->IsInitialized();
+}
+
+gfxFontEntry* gfxPlatformFontList::FindFontForFamily(
+    nsPresContext* aPresContext, const nsACString& aFamily,
+    const gfxFontStyle* aStyle) {
+  AutoLock lock(mLock);
+
+  nsAutoCString key;
+  GenerateFontListKey(aFamily, key);
+
+  FontFamily family = FindFamily(aPresContext, key);
+  if (family.IsNull()) {
+    return nullptr;
+  }
+  if (family.mShared) {
+    auto face = family.mShared->FindFaceForStyle(SharedFontList(), *aStyle);
+    if (!face) {
+      return nullptr;
+    }
+    return GetOrCreateFontEntryLocked(face, family.mShared);
+  }
+  return family.mUnshared->FindFontForStyle(*aStyle);
+}
+
+gfxFontEntry* gfxPlatformFontList::GetOrCreateFontEntryLocked(
+    fontlist::Face* aFace, const fontlist::Family* aFamily) {
+  return mFontEntries
+      .LookupOrInsertWith(aFace,
+                          [=] { return CreateFontEntry(aFace, aFamily); })
+      .get();
+}
+
+void gfxPlatformFontList::AddOtherFamilyNames(
+    gfxFontFamily* aFamilyEntry, const nsTArray<nsCString>& aOtherFamilyNames) {
+  AutoLock lock(mLock);
+
+  for (const auto& name : aOtherFamilyNames) {
+    nsAutoCString key;
+    GenerateFontListKey(name, key);
+
+    mOtherFamilyNames.LookupOrInsertWith(key, [&] {
+      LOG_FONTLIST(
+          ("(fontlist-otherfamily) canonical family: %s, other family: %s\n",
+           aFamilyEntry->Name().get(), name.get()));
+      if (mBadUnderlineFamilyNames.ContainsSorted(key)) {
+        aFamilyEntry->SetBadUnderlineFamily();
+      }
+      return RefPtr{aFamilyEntry};
+    });
+  }
+}
+
+void gfxPlatformFontList::AddFullnameLocked(gfxFontEntry* aFontEntry,
+                                            const nsCString& aFullname) {
+  mExtraNames->mFullnames.LookupOrInsertWith(aFullname, [&] {
+    LOG_FONTLIST(("(fontlist-fullname) name: %s, fullname: %s\n",
+                  aFontEntry->Name().get(), aFullname.get()));
+    return RefPtr{aFontEntry};
+  });
+}
+
+void gfxPlatformFontList::AddPostscriptNameLocked(
+    gfxFontEntry* aFontEntry, const nsCString& aPostscriptName) {
+  mExtraNames->mPostscriptNames.LookupOrInsertWith(aPostscriptName, [&] {
+    LOG_FONTLIST(("(fontlist-postscript) name: %s, psname: %s\n",
+                  aFontEntry->Name().get(), aPostscriptName.get()));
+    return RefPtr{aFontEntry};
+  });
+}
+
+bool gfxPlatformFontList::GetStandardFamilyName(const nsCString& aFontName,
+                                                nsACString& aFamilyName) {
+  AutoLock lock(mLock);
+  FontFamily family = FindFamily(nullptr, aFontName);
+  if (family.IsNull()) {
+    return false;
+  }
+  return GetLocalizedFamilyName(family, aFamilyName);
+}
+
+bool gfxPlatformFontList::GetLocalizedFamilyName(const FontFamily& aFamily,
+                                                 nsACString& aFamilyName) {
+  if (aFamily.mShared) {
+    aFamilyName = SharedFontList()->LocalizedFamilyName(aFamily.mShared);
+    return true;
+  }
+  if (aFamily.mUnshared) {
+    aFamily.mUnshared->LocalizedName(aFamilyName);
+    return true;
+  }
+  return false;  // leaving the aFamilyName outparam untouched
+}
+
+FamilyAndGeneric gfxPlatformFontList::GetDefaultFontFamily(
+    const nsACString& aLangGroup, const nsACString& aGenericFamily) {
+  if (NS_WARN_IF(aLangGroup.IsEmpty()) ||
+      NS_WARN_IF(aGenericFamily.IsEmpty())) {
+    return FamilyAndGeneric();
+  }
+
+  AutoLock lock(mLock);
+
+  nsAutoCString value;
+  AutoTArray<nsCString, 4> names;
+  if (mFontPrefs->LookupNameList(PrefName(aGenericFamily, aLangGroup), value)) {
+    gfxFontUtils::ParseFontList(value, names);
+  }
+
+  for (const nsCString& name : names) {
+    FontFamily family = FindFamily(nullptr, name);
+    if (!family.IsNull()) {
+      return FamilyAndGeneric(family);
+    }
+  }
+
+  return FamilyAndGeneric();
+}
+
+ShmemCharMapHashEntry::ShmemCharMapHashEntry(const gfxSparseBitSet* aCharMap)
+    : mList(gfxPlatformFontList::PlatformFontList()->SharedFontList()),
+      mCharMap(),
+      mHash(aCharMap->GetChecksum()) {
+  size_t len = SharedBitSet::RequiredSize(*aCharMap);
+  mCharMap = mList->Alloc(len);
+  SharedBitSet::Create(mCharMap.ToPtr(mList), len, *aCharMap);
+}
+
+fontlist::Pointer gfxPlatformFontList::GetShmemCharMapLocked(
+    const gfxSparseBitSet* aCmap) {
+  auto* entry = mShmemCharMaps.GetEntry(aCmap);
+  if (!entry) {
+    entry = mShmemCharMaps.PutEntry(aCmap);
+  }
+  return entry->GetCharMap();
+}
+
+// lookup cmap in the shared cmap set, adding if not already present
+already_AddRefed<gfxCharacterMap> gfxPlatformFontList::FindCharMap(
+    gfxCharacterMap* aCmap) {
+  AutoLock lock(mLock);
+  aCmap->CalcHash();
+  gfxCharacterMap* cmap = mSharedCmaps.PutEntry(aCmap)->GetKey();
+  cmap->mShared = true;
+  return do_AddRef(cmap);
+}
+
+// remove the cmap from the shared cmap set
+void gfxPlatformFontList::RemoveCmap(const gfxCharacterMap* aCharMap) {
+  AutoLock lock(mLock);
+  // skip lookups during teardown
+  if (mSharedCmaps.Count() == 0) {
+    return;
+  }
+
+  // cmap needs to match the entry *and* be the same ptr before removing
+  CharMapHashKey* found =
+      mSharedCmaps.GetEntry(const_cast<gfxCharacterMap*>(aCharMap));
+  if (found && found->GetKey() == aCharMap) {
+    mSharedCmaps.RemoveEntry(found);
+  }
+}
+
+static void GetSystemUIFontFamilies([[maybe_unused]] nsAtom* aLangGroup,
+                                    nsTArray<nsCString>& aFamilies) {
+  // TODO: On macOS, use CTCreateUIFontForLanguage or such thing (though the
+  // code below ends up using [NSFont systemFontOfSize: 0.0].
+  nsFont systemFont;
+  gfxFontStyle fontStyle;
+  nsAutoString systemFontName;
+  if (!LookAndFeel::GetFont(StyleSystemFont::Menu, systemFontName, fontStyle)) {
+    return;
+  }
+  systemFontName.Trim("\"'");
+  CopyUTF16toUTF8(systemFontName, *aFamilies.AppendElement());
+}
+
+void gfxPlatformFontList::ResolveGenericFontNames(
+    nsPresContext* aPresContext, StyleGenericFontFamily aGenericType,
+    eFontPrefLang aPrefLang, PrefFontList* aGenericFamilies) {
+  const char* langGroupStr = GetPrefLangName(aPrefLang);
+  const char* generic = GetGenericName(aGenericType);
+
+  if (!generic) {
+    return;
+  }
+
+  AutoTArray<nsCString, 4> genericFamilies;
+
+  // load family for "font.name.generic.lang"
+  PrefName prefName(generic, langGroupStr);
+  nsAutoCString value;
+  if (mFontPrefs->LookupName(prefName, value)) {
+    gfxFontUtils::ParseFontList(value, genericFamilies);
+  }
+
+  // load fonts for "font.name-list.generic.lang"
+  if (mFontPrefs->LookupNameList(prefName, value)) {
+    gfxFontUtils::ParseFontList(value, genericFamilies);
+  }
+
+  nsAtom* langGroup = GetLangGroupForPrefLang(aPrefLang);
+  MOZ_ASSERT(langGroup, "null lang group for pref lang");
+
+  if (aGenericType == StyleGenericFontFamily::SystemUi) {
+    GetSystemUIFontFamilies(langGroup, genericFamilies);
+  }
+
+  GetFontFamiliesFromGenericFamilies(
+      aPresContext, aGenericType, genericFamilies, langGroup, aGenericFamilies);
+
+#if 0  // dump out generic mappings
+    printf("%s ===> ", NamePref(generic, langGroupStr).get());
+    for (uint32_t k = 0; k < aGenericFamilies->Length(); k++) {
+        if (k > 0) printf(", ");
+        printf("%s", (*aGenericFamilies)[k].mIsShared
+            ? (*aGenericFamilies)[k].mShared->DisplayName().AsString(SharedFontList()).get()
+            : (*aGenericFamilies)[k].mUnshared->Name().get());
+    }
+    printf("\n");
+#endif
+}
+
+void gfxPlatformFontList::ResolveEmojiFontNames(
+    nsPresContext* aPresContext, PrefFontList* aGenericFamilies) {
+  // emoji preference has no lang name
+  AutoTArray<nsCString, 4> genericFamilies;
+
+  nsAutoCString value;
+  if (mFontPrefs->LookupNameList(PrefName("emoji", ""), value)) {
+    gfxFontUtils::ParseFontList(value, genericFamilies);
+  }
+
+  GetFontFamiliesFromGenericFamilies(
+      aPresContext, StyleGenericFontFamily::MozEmoji, genericFamilies, nullptr,
+      aGenericFamilies);
+}
+
+void gfxPlatformFontList::GetFontFamiliesFromGenericFamilies(
+    nsPresContext* aPresContext, StyleGenericFontFamily aGenericType,
+    nsTArray<nsCString>& aGenericNameFamilies, nsAtom* aLangGroup,
+    PrefFontList* aGenericFamilies) {
+  // lookup and add platform fonts uniquely
+  for (const nsCString& genericFamily : aGenericNameFamilies) {
+    AutoTArray<FamilyAndGeneric, 10> families;
+    FindAndAddFamiliesLocked(aPresContext, aGenericType, genericFamily,
+                             &families, FindFamiliesFlags(0), nullptr,
+                             aLangGroup);
+    for (const FamilyAndGeneric& f : families) {
+      if (!aGenericFamilies->Contains(f.mFamily)) {
+        aGenericFamilies->AppendElement(f.mFamily);
+      }
+    }
+  }
+}
+
+gfxPlatformFontList::PrefFontList*
+gfxPlatformFontList::GetPrefFontsLangGroupLocked(
+    nsPresContext* aPresContext, StyleGenericFontFamily aGenericType,
+    eFontPrefLang aPrefLang) {
+  if (aGenericType == StyleGenericFontFamily::MozEmoji ||
+      aPrefLang == eFontPrefLang_Emoji) {
+    // Emoji font has no lang
+    PrefFontList* prefFonts = mEmojiPrefFont.get();
+    if (MOZ_UNLIKELY(!prefFonts)) {
+      prefFonts = new PrefFontList;
+      ResolveEmojiFontNames(aPresContext, prefFonts);
+      mEmojiPrefFont.reset(prefFonts);
+    }
+    return prefFonts;
+  }
+
+  auto index = static_cast<size_t>(aGenericType);
+  PrefFontList* prefFonts = mLangGroupPrefFonts[aPrefLang][index].get();
+  if (MOZ_UNLIKELY(!prefFonts)) {
+    prefFonts = new PrefFontList;
+    ResolveGenericFontNames(aPresContext, aGenericType, aPrefLang, prefFonts);
+    mLangGroupPrefFonts[aPrefLang][index].reset(prefFonts);
+  }
+  return prefFonts;
+}
+
+void gfxPlatformFontList::AddGenericFonts(
+    nsPresContext* aPresContext, StyleGenericFontFamily aGenericType,
+    nsAtom* aLanguage, nsTArray<FamilyAndGeneric>& aFamilyList) {
+  AutoLock lock(mLock);
+
+  // map lang ==> langGroup
+  nsAtom* langGroup = GetLangGroup(aLanguage);
+
+  // langGroup ==> prefLang
+  eFontPrefLang prefLang = GetFontPrefLangFor(langGroup);
+
+  // lookup pref fonts
+  PrefFontList* prefFonts =
+      GetPrefFontsLangGroupLocked(aPresContext, aGenericType, prefLang);
+
+  if (!prefFonts->IsEmpty()) {
+    aFamilyList.SetCapacity(aFamilyList.Length() + prefFonts->Length());
+    for (auto& f : *prefFonts) {
+      aFamilyList.AppendElement(FamilyAndGeneric(f, aGenericType));
+    }
+  }
+}
+
+static nsAtom* PrefLangToLangGroups(uint32_t aIndex) {
+  // static array here avoids static constructor
+  static nsAtom* gPrefLangToLangGroups[] = {
+#define FONT_PREF_LANG(enum_id_, str_, atom_id_) nsGkAtoms::atom_id_
+#include "gfxFontPrefLangList.h"
+#undef FONT_PREF_LANG
+  };
+
+  return aIndex < ArrayLength(gPrefLangToLangGroups)
+             ? gPrefLangToLangGroups[aIndex]
+             : nsGkAtoms::Unicode;
+}
+
+eFontPrefLang gfxPlatformFontList::GetFontPrefLangFor(const char* aLang) {
+  if (!aLang || !aLang[0]) {
+    return eFontPrefLang_Others;
+  }
+  for (uint32_t i = 0; i < ArrayLength(gPrefLangNames); ++i) {
+    if (!nsCRT::strcasecmp(gPrefLangNames[i], aLang)) {
+      return eFontPrefLang(i);
+    }
+  }
+  return eFontPrefLang_Others;
+}
+
+eFontPrefLang gfxPlatformFontList::GetFontPrefLangFor(nsAtom* aLang) {
+  if (!aLang) return eFontPrefLang_Others;
+  nsAutoCString lang;
+  aLang->ToUTF8String(lang);
+  return GetFontPrefLangFor(lang.get());
+}
+
+nsAtom* gfxPlatformFontList::GetLangGroupForPrefLang(eFontPrefLang aLang) {
+  // the special CJK set pref lang should be resolved into separate
+  // calls to individual CJK pref langs before getting here
+  NS_ASSERTION(aLang != eFontPrefLang_CJKSet, "unresolved CJK set pref lang");
+
+  return PrefLangToLangGroups(uint32_t(aLang));
+}
+
+const char* gfxPlatformFontList::GetPrefLangName(eFontPrefLang aLang) {
+  if (uint32_t(aLang) < ArrayLength(gPrefLangNames)) {
+    return gPrefLangNames[uint32_t(aLang)];
+  }
+  return nullptr;
+}
+
+eFontPrefLang gfxPlatformFontList::GetFontPrefLangFor(uint32_t aCh) {
+  switch (ublock_getCode(aCh)) {
+    case UBLOCK_BASIC_LATIN:
+    case UBLOCK_LATIN_1_SUPPLEMENT:
+    case UBLOCK_LATIN_EXTENDED_A:
+    case UBLOCK_LATIN_EXTENDED_B:
+    case UBLOCK_IPA_EXTENSIONS:
+    case UBLOCK_SPACING_MODIFIER_LETTERS:
+    case UBLOCK_LATIN_EXTENDED_ADDITIONAL:
+    case UBLOCK_LATIN_EXTENDED_C:
+    case UBLOCK_LATIN_EXTENDED_D:
+    case UBLOCK_LATIN_EXTENDED_E:
+    case UBLOCK_PHONETIC_EXTENSIONS:
+      return eFontPrefLang_Western;
+    case UBLOCK_GREEK:
+    case UBLOCK_GREEK_EXTENDED:
+      return eFontPrefLang_Greek;
+    case UBLOCK_CYRILLIC:
+    case UBLOCK_CYRILLIC_SUPPLEMENT:
+    case UBLOCK_CYRILLIC_EXTENDED_A:
+    case UBLOCK_CYRILLIC_EXTENDED_B:
+    case UBLOCK_CYRILLIC_EXTENDED_C:
+      return eFontPrefLang_Cyrillic;
+    case UBLOCK_ARMENIAN:
+      return eFontPrefLang_Armenian;
+    case UBLOCK_HEBREW:
+      return eFontPrefLang_Hebrew;
+    case UBLOCK_ARABIC:
+    case UBLOCK_ARABIC_PRESENTATION_FORMS_A:
+    case UBLOCK_ARABIC_PRESENTATION_FORMS_B:
+    case UBLOCK_ARABIC_SUPPLEMENT:
+    case UBLOCK_ARABIC_EXTENDED_A:
+    case UBLOCK_ARABIC_MATHEMATICAL_ALPHABETIC_SYMBOLS:
+      return eFontPrefLang_Arabic;
+    case UBLOCK_DEVANAGARI:
+    case UBLOCK_DEVANAGARI_EXTENDED:
+      return eFontPrefLang_Devanagari;
+    case UBLOCK_BENGALI:
+      return eFontPrefLang_Bengali;
+    case UBLOCK_GURMUKHI:
+      return eFontPrefLang_Gurmukhi;
+    case UBLOCK_GUJARATI:
+      return eFontPrefLang_Gujarati;
+    case UBLOCK_ORIYA:
+      return eFontPrefLang_Oriya;
+    case UBLOCK_TAMIL:
+      return eFontPrefLang_Tamil;
+    case UBLOCK_TELUGU:
+      return eFontPrefLang_Telugu;
+    case UBLOCK_KANNADA:
+      return eFontPrefLang_Kannada;
+    case UBLOCK_MALAYALAM:
+      return eFontPrefLang_Malayalam;
+    case UBLOCK_SINHALA:
+    case UBLOCK_SINHALA_ARCHAIC_NUMBERS:
+      return eFontPrefLang_Sinhala;
+    case UBLOCK_THAI:
+      return eFontPrefLang_Thai;
+    case UBLOCK_TIBETAN:
+      return eFontPrefLang_Tibetan;
+    case UBLOCK_GEORGIAN:
+    case UBLOCK_GEORGIAN_SUPPLEMENT:
+    case UBLOCK_GEORGIAN_EXTENDED:
+      return eFontPrefLang_Georgian;
+    case UBLOCK_HANGUL_JAMO:
+    case UBLOCK_HANGUL_COMPATIBILITY_JAMO:
+    case UBLOCK_HANGUL_SYLLABLES:
+    case UBLOCK_HANGUL_JAMO_EXTENDED_A:
+    case UBLOCK_HANGUL_JAMO_EXTENDED_B:
+      return eFontPrefLang_Korean;
+    case UBLOCK_ETHIOPIC:
+    case UBLOCK_ETHIOPIC_EXTENDED:
+    case UBLOCK_ETHIOPIC_SUPPLEMENT:
+    case UBLOCK_ETHIOPIC_EXTENDED_A:
+      return eFontPrefLang_Ethiopic;
+    case UBLOCK_UNIFIED_CANADIAN_ABORIGINAL_SYLLABICS:
+    case UBLOCK_UNIFIED_CANADIAN_ABORIGINAL_SYLLABICS_EXTENDED:
+      return eFontPrefLang_Canadian;
+    case UBLOCK_KHMER:
+    case UBLOCK_KHMER_SYMBOLS:
+      return eFontPrefLang_Khmer;
+    case UBLOCK_CJK_RADICALS_SUPPLEMENT:
+    case UBLOCK_KANGXI_RADICALS:
+    case UBLOCK_IDEOGRAPHIC_DESCRIPTION_CHARACTERS:
+    case UBLOCK_CJK_SYMBOLS_AND_PUNCTUATION:
+    case UBLOCK_HIRAGANA:
+    case UBLOCK_KATAKANA:
+    case UBLOCK_BOPOMOFO:
+    case UBLOCK_KANBUN:
+    case UBLOCK_BOPOMOFO_EXTENDED:
+    case UBLOCK_ENCLOSED_CJK_LETTERS_AND_MONTHS:
+    case UBLOCK_CJK_COMPATIBILITY:
+    case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A:
+    case UBLOCK_CJK_UNIFIED_IDEOGRAPHS:
+    case UBLOCK_CJK_COMPATIBILITY_IDEOGRAPHS:
+    case UBLOCK_CJK_COMPATIBILITY_FORMS:
+    case UBLOCK_SMALL_FORM_VARIANTS:
+    case UBLOCK_HALFWIDTH_AND_FULLWIDTH_FORMS:
+    case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_B:
+    case UBLOCK_CJK_COMPATIBILITY_IDEOGRAPHS_SUPPLEMENT:
+    case UBLOCK_KATAKANA_PHONETIC_EXTENSIONS:
+    case UBLOCK_CJK_STROKES:
+    case UBLOCK_VERTICAL_FORMS:
+    case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_C:
+    case UBLOCK_KANA_SUPPLEMENT:
+    case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_D:
+    case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_E:
+    case UBLOCK_IDEOGRAPHIC_SYMBOLS_AND_PUNCTUATION:
+    case UBLOCK_CJK_UNIFIED_IDEOGRAPHS_EXTENSION_F:
+    case UBLOCK_KANA_EXTENDED_A:
+      return eFontPrefLang_CJKSet;
+    case UBLOCK_MATHEMATICAL_OPERATORS:
+    case UBLOCK_MATHEMATICAL_ALPHANUMERIC_SYMBOLS:
+    case UBLOCK_MISCELLANEOUS_MATHEMATICAL_SYMBOLS_A:
+    case UBLOCK_MISCELLANEOUS_MATHEMATICAL_SYMBOLS_B:
+    case UBLOCK_SUPPLEMENTAL_MATHEMATICAL_OPERATORS:
+      return eFontPrefLang_Mathematics;
+    default:
+      return eFontPrefLang_Others;
+  }
+}
+
+bool gfxPlatformFontList::IsLangCJK(eFontPrefLang aLang) {
+  switch (aLang) {
+    case eFontPrefLang_Japanese:
+    case eFontPrefLang_ChineseTW:
+    case eFontPrefLang_ChineseCN:
+    case eFontPrefLang_ChineseHK:
+    case eFontPrefLang_Korean:
+    case eFontPrefLang_CJKSet:
+      return true;
+    default:
+      return false;
+  }
+}
+
+void gfxPlatformFontList::GetLangPrefs(eFontPrefLang aPrefLangs[],
+                                       uint32_t& aLen, eFontPrefLang aCharLang,
+                                       eFontPrefLang aPageLang) {
+  AutoLock lock(mLock);
+  if (IsLangCJK(aCharLang)) {
+    AppendCJKPrefLangs(aPrefLangs, aLen, aCharLang, aPageLang);
+  } else {
+    AppendPrefLang(aPrefLangs, aLen, aCharLang);
+  }
+
+  AppendPrefLang(aPrefLangs, aLen, eFontPrefLang_Others);
+}
+
+void gfxPlatformFontList::AppendCJKPrefLangs(eFontPrefLang aPrefLangs[],
+                                             uint32_t& aLen,
+                                             eFontPrefLang aCharLang,
+                                             eFontPrefLang aPageLang) {
+  // prefer the lang specified by the page *if* CJK
+  if (IsLangCJK(aPageLang)) {
+    AppendPrefLang(aPrefLangs, aLen, aPageLang);
+  }
+
+  // if not set up, set up the default CJK order, based on accept lang
+  // settings and locale
+  if (mCJKPrefLangs.Length() == 0) {
+    // temp array
+    eFontPrefLang tempPrefLangs[kMaxLenPrefLangList];
+    uint32_t tempLen = 0;
+
+    // Add the CJK pref fonts from accept languages, the order should be same
+    // order. We use gfxFontUtils::GetPrefsFontList to read the list even
+    // though it's not actually a list of fonts but of lang codes; the format
+    // is the same.
+    AutoTArray<nsCString, 5> list;
+    gfxFontUtils::GetPrefsFontList("intl.accept_languages", list, true);
+    for (const auto& lang : list) {
+      eFontPrefLang fpl = GetFontPrefLangFor(lang.get());
+      switch (fpl) {
+        case eFontPrefLang_Japanese:
+        case eFontPrefLang_Korean:
+        case eFontPrefLang_ChineseCN:
+        case eFontPrefLang_ChineseHK:
+        case eFontPrefLang_ChineseTW:
+          AppendPrefLang(tempPrefLangs, tempLen, fpl);
+          break;
+        default:
+          break;
+      }
+    }
+
+    // Try using app's locale
+    nsAutoCString localeStr;
+    LocaleService::GetInstance()->GetAppLocaleAsBCP47(localeStr);
+
+    {
+      Locale locale;
+      if (LocaleParser::TryParse(localeStr, locale).isOk() &&
+          locale.Canonicalize().isOk()) {
+        if (locale.Language().EqualTo("ja")) {
+          AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_Japanese);
+        } else if (locale.Language().EqualTo("zh")) {
+          if (locale.Region().EqualTo("CN")) {
+            AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseCN);
+          } else if (locale.Region().EqualTo("TW")) {
+            AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseTW);
+          } else if (locale.Region().EqualTo("HK")) {
+            AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseHK);
+          }
+        } else if (locale.Language().EqualTo("ko")) {
+          AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_Korean);
+        }
+      }
+    }
+
+    // Then add the known CJK prefs in order of system preferred locales
+    AutoTArray<nsCString, 5> prefLocales;
+    prefLocales.AppendElement("ja"_ns);
+    prefLocales.AppendElement("zh-CN"_ns);
+    prefLocales.AppendElement("zh-TW"_ns);
+    prefLocales.AppendElement("zh-HK"_ns);
+    prefLocales.AppendElement("ko"_ns);
+
+    AutoTArray<nsCString, 16> sysLocales;
+    AutoTArray<nsCString, 16> negLocales;
+    if (NS_SUCCEEDED(
+            OSPreferences::GetInstance()->GetSystemLocales(sysLocales))) {
+      LocaleService::GetInstance()->NegotiateLanguages(
+          sysLocales, prefLocales, ""_ns,
+          LocaleService::kLangNegStrategyFiltering, negLocales);
+      for (const auto& localeStr : negLocales) {
+        Locale locale;
+        if (LocaleParser::TryParse(localeStr, locale).isOk() &&
+            locale.Canonicalize().isOk()) {
+          if (locale.Language().EqualTo("ja")) {
+            AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_Japanese);
+          } else if (locale.Language().EqualTo("zh")) {
+            if (locale.Region().EqualTo("CN")) {
+              AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseCN);
+            } else if (locale.Region().EqualTo("TW")) {
+              AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseTW);
+            } else if (locale.Region().EqualTo("HK")) {
+              AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseHK);
+            }
+          } else if (locale.Language().EqualTo("ko")) {
+            AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_Korean);
+          }
+        }
+      }
+    }
+
+    // Last resort... set up CJK font prefs in the order listed by the user-
+    // configurable ordering pref.
+    gfxFontUtils::GetPrefsFontList(kCJKFallbackOrderPref, list);
+    for (const auto& item : list) {
+      eFontPrefLang fpl = GetFontPrefLangFor(item.get());
+      switch (fpl) {
+        case eFontPrefLang_Japanese:
+        case eFontPrefLang_Korean:
+        case eFontPrefLang_ChineseCN:
+        case eFontPrefLang_ChineseHK:
+        case eFontPrefLang_ChineseTW:
+          AppendPrefLang(tempPrefLangs, tempLen, fpl);
+          break;
+        default:
+          break;
+      }
+    }
+
+    // Truly-last resort... try Chinese font prefs before Japanese because
+    // they tend to have more complete character coverage, and therefore less
+    // risk of "ransom-note" effects.
+    // (If the kCJKFallbackOrderPref was fully populated, as it is by default,
+    // this will do nothing as all these values are already present.)
+    AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseCN);
+    AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseHK);
+    AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_ChineseTW);
+    AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_Japanese);
+    AppendPrefLang(tempPrefLangs, tempLen, eFontPrefLang_Korean);
+
+    // copy into the cached array
+    for (const auto lang : Span<eFontPrefLang>(tempPrefLangs, tempLen)) {
+      mCJKPrefLangs.AppendElement(lang);
+    }
+  }
+
+  // append in cached CJK langs
+  for (const auto lang : mCJKPrefLangs) {
+    AppendPrefLang(aPrefLangs, aLen, eFontPrefLang(lang));
+  }
+}
+
+void gfxPlatformFontList::AppendPrefLang(eFontPrefLang aPrefLangs[],
+                                         uint32_t& aLen,
+                                         eFontPrefLang aAddLang) {
+  if (aLen >= kMaxLenPrefLangList) {
+    return;
+  }
+
+  // If the lang is already present, just ignore the addition.
+  for (const auto lang : Span<eFontPrefLang>(aPrefLangs, aLen)) {
+    if (lang == aAddLang) {
+      return;
+    }
+  }
+
+  aPrefLangs[aLen++] = aAddLang;
+}
+
+StyleGenericFontFamily gfxPlatformFontList::GetDefaultGeneric(
+    eFontPrefLang aLang) {
+  if (aLang == eFontPrefLang_Emoji) {
+    return StyleGenericFontFamily::MozEmoji;
+  }
+
+  AutoLock lock(mLock);
+
+  if (uint32_t(aLang) < ArrayLength(gPrefLangNames)) {
+    return mDefaultGenericsLangGroup[uint32_t(aLang)];
+  }
+  return StyleGenericFontFamily::Serif;
+}
+
+FontFamily gfxPlatformFontList::GetDefaultFont(nsPresContext* aPresContext,
+                                               const gfxFontStyle* aStyle) {
+  AutoLock lock(mLock);
+  return GetDefaultFontLocked(aPresContext, aStyle);
+}
+
+FontFamily gfxPlatformFontList::GetDefaultFontLocked(
+    nsPresContext* aPresContext, const gfxFontStyle* aStyle) {
+  FontFamily family = GetDefaultFontForPlatform(aPresContext, aStyle);
+  if (!family.IsNull()) {
+    return family;
+  }
+  // Something has gone wrong and we were unable to retrieve a default font
+  // from the platform. (Likely the whitelist has blocked all potential
+  // default fonts.) As a last resort, we return the first font in our list.
+  if (SharedFontList()) {
+    MOZ_RELEASE_ASSERT(SharedFontList()->NumFamilies() > 0);
+    return FontFamily(SharedFontList()->Families());
+  }
+  MOZ_RELEASE_ASSERT(mFontFamilies.Count() > 0);
+  return FontFamily(mFontFamilies.ConstIter().Data());
+}
+
+void gfxPlatformFontList::GetFontFamilyNames(
+    nsTArray<nsCString>& aFontFamilyNames) {
+  if (SharedFontList()) {
+    fontlist::FontList* list = SharedFontList();
+    const fontlist::Family* families = list->Families();
+    if (families) {
+      for (uint32_t i = 0, n = list->NumFamilies(); i < n; i++) {
+        const fontlist::Family& family = families[i];
+        if (!family.IsHidden()) {
+          aFontFamilyNames.AppendElement(family.DisplayName().AsString(list));
+        }
+      }
+    }
+  } else {
+    for (const RefPtr<gfxFontFamily>& family : mFontFamilies.Values()) {
+      if (!family->IsHidden()) {
+        aFontFamilyNames.AppendElement(family->Name());
+      }
+    }
+  }
+}
+
+nsAtom* gfxPlatformFontList::GetLangGroup(nsAtom* aLanguage) {
+  // map lang ==> langGroup
+  nsAtom* langGroup = nullptr;
+  if (aLanguage) {
+    langGroup = mLangService->GetLanguageGroup(aLanguage);
+  }
+  if (!langGroup) {
+    langGroup = nsGkAtoms::Unicode;
+  }
+  return langGroup;
+}
+
+/* static */ const char* gfxPlatformFontList::GetGenericName(
+    StyleGenericFontFamily aGenericType) {
+  // type should be standard generic type at this point
+  // map generic type to string
+  switch (aGenericType) {
+    case StyleGenericFontFamily::Serif:
+      return "serif";
+    case StyleGenericFontFamily::SansSerif:
+      return "sans-serif";
+    case StyleGenericFontFamily::Monospace:
+      return "monospace";
+    case StyleGenericFontFamily::Cursive:
+      return "cursive";
+    case StyleGenericFontFamily::Fantasy:
+      return "fantasy";
+    case StyleGenericFontFamily::SystemUi:
+      return "system-ui";
+    case StyleGenericFontFamily::MozEmoji:
+      return "-moz-emoji";
+    case StyleGenericFontFamily::None:
+      break;
+  }
+  MOZ_ASSERT_UNREACHABLE("Unknown generic");
+  return nullptr;
+}
+
+void gfxPlatformFontList::InitLoader() {
+  GetFontFamilyNames(mFontInfo->mFontFamiliesToLoad);
+  mStartIndex = 0;
+  mNumFamilies = mFontInfo->mFontFamiliesToLoad.Length();
+  memset(&(mFontInfo->mLoadStats), 0, sizeof(mFontInfo->mLoadStats));
+}
+
+#define FONT_LOADER_MAX_TIMESLICE \
+  20  // max time for one pass through RunLoader = 20ms
+
+bool gfxPlatformFontList::LoadFontInfo() {
+  AutoLock lock(mLock);
+  TimeStamp start = TimeStamp::Now();
+  uint32_t i, endIndex = mNumFamilies;
+  fontlist::FontList* list = SharedFontList();
+  bool loadCmaps =
+      !list && (!UsesSystemFallback() ||
+                gfxPlatform::GetPlatform()->UseCmapsDuringSystemFallback());
+
+  // for each font family, load in various font info
+  for (i = mStartIndex; i < endIndex; i++) {
+    nsAutoCString key;
+    GenerateFontListKey(mFontInfo->mFontFamiliesToLoad[i], key);
+
+    if (list) {
+      fontlist::Family* family = list->FindFamily(key);
+      if (!family) {
+        continue;
+      }
+      ReadFaceNamesForFamily(family, NeedFullnamePostscriptNames());
+    } else {
+      // lookup in canonical (i.e. English) family name list
+      gfxFontFamily* familyEntry = mFontFamilies.GetWeak(key);
+      if (!familyEntry) {
+        continue;
+      }
+
+      // read in face names
+      familyEntry->ReadFaceNames(this, NeedFullnamePostscriptNames(),
+                                 mFontInfo);
+
+      // load the cmaps if needed
+      if (loadCmaps) {
+        familyEntry->ReadAllCMAPs(mFontInfo);
+      }
+    }
+
+    // Limit the time spent reading fonts in one pass, unless the font-loader
+    // delay was set to zero, in which case we run to completion even if it
+    // causes some jank.
+    if (StaticPrefs::gfx_font_loader_delay_AtStartup() > 0) {
+      TimeDuration elapsed = TimeStamp::Now() - start;
+      if (elapsed.ToMilliseconds() > FONT_LOADER_MAX_TIMESLICE &&
+          i + 1 != endIndex) {
+        endIndex = i + 1;
+        break;
+      }
+    }
+  }
+
+  mStartIndex = endIndex;
+  bool done = mStartIndex >= mNumFamilies;
+
+  if (LOG_FONTINIT_ENABLED()) {
+    TimeDuration elapsed = TimeStamp::Now() - start;
+    LOG_FONTINIT(("(fontinit) fontloader load pass %8.2f ms done %s\n",
+                  elapsed.ToMilliseconds(), (done ? "true" : "false")));
+  }
+
+  if (done) {
+    mOtherFamilyNamesInitialized = true;
+    CancelInitOtherFamilyNamesTask();
+    mFaceNameListsInitialized = true;
+  }
+
+  return done;
+}
+
+void gfxPlatformFontList::CleanupLoader() {
+  AutoLock lock(mLock);
+
+  mFontFamiliesToLoad.Clear();
+  mNumFamilies = 0;
+  bool rebuilt = false, forceReflow = false;
+
+  // if had missed face names that are now available, force reflow all
+  if (mFaceNamesMissed) {
+    rebuilt = std::any_of(mFaceNamesMissed->cbegin(), mFaceNamesMissed->cend(),
+                          [&](const auto& key) {
+                            mLock.AssertCurrentThreadIn();
+                            return FindFaceName(key);
+                          });
+    if (rebuilt) {
+      RebuildLocalFonts();
+    }
+
+    mFaceNamesMissed = nullptr;
+  }
+
+  if (mOtherNamesMissed) {
+    forceReflow = std::any_of(
+        mOtherNamesMissed->cbegin(), mOtherNamesMissed->cend(),
+        [&](const auto& key) {
+          mLock.AssertCurrentThreadIn();
+          return FindUnsharedFamily(
+              nullptr, key,
+              (FindFamiliesFlags::eForceOtherFamilyNamesLoading |
+               FindFamiliesFlags::eNoAddToNamesMissedWhenSearching));
+        });
+    if (forceReflow) {
+      ForceGlobalReflowLocked(gfxPlatform::NeedsReframe::No);
+    }
+
+    mOtherNamesMissed = nullptr;
+  }
+
+  if (LOG_FONTINIT_ENABLED() && mFontInfo) {
+    LOG_FONTINIT(
+        ("(fontinit) fontloader load thread took %8.2f ms "
+         "%d families %d fonts %d cmaps "
+         "%d facenames %d othernames %s %s",
+         mLoadTime.ToMilliseconds(), mFontInfo->mLoadStats.families,
+         mFontInfo->mLoadStats.fonts, mFontInfo->mLoadStats.cmaps,
+         mFontInfo->mLoadStats.facenames, mFontInfo->mLoadStats.othernames,
+         (rebuilt ? "(userfont sets rebuilt)" : ""),
+         (forceReflow ? "(global reflow)" : "")));
+  }
+
+  gfxFontInfoLoader::CleanupLoader();
+}
+
+void gfxPlatformFontList::ForceGlobalReflowLocked(
+    gfxPlatform::NeedsReframe aNeedsReframe,
+    gfxPlatform::BroadcastToChildren aBroadcastToChildren) {
+  if (!NS_IsMainThread()) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "gfxPlatformFontList::ForceGlobalReflowLocked",
+        [aNeedsReframe, aBroadcastToChildren] {
+          gfxPlatform::ForceGlobalReflow(aNeedsReframe, aBroadcastToChildren);
+        }));
+    return;
+  }
+
+  AutoUnlock unlock(mLock);
+  gfxPlatform::ForceGlobalReflow(aNeedsReframe, aBroadcastToChildren);
+}
+
+void gfxPlatformFontList::GetPrefsAndStartLoader() {
+  // If we're already in shutdown, there's no point in starting this, and it
+  // could trigger an assertion if we try to use the Thread Manager too late.
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return;
+  }
+  uint32_t delay = std::max(1u, StaticPrefs::gfx_font_loader_delay_AtStartup());
+  if (NS_IsMainThread()) {
+    StartLoader(delay);
+  } else {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "StartLoader callback", [delay, fontList = this] {
+          fontList->Lock();
+          fontList->StartLoader(delay);
+          fontList->Unlock();
+        }));
+  }
+}
+
+void gfxPlatformFontList::RebuildLocalFonts(bool aForgetLocalFaces) {
+  for (auto* fontset : mUserFontSetList) {
+    if (aForgetLocalFaces) {
+      fontset->ForgetLocalFaces();
+    }
+    fontset->RebuildLocalRules();
+  }
+}
+
+void gfxPlatformFontList::ClearLangGroupPrefFontsLocked() {
+  for (uint32_t i = eFontPrefLang_First;
+       i < eFontPrefLang_First + eFontPrefLang_Count; i++) {
+    auto& prefFontsLangGroup = mLangGroupPrefFonts[i];
+    for (auto& pref : prefFontsLangGroup) {
+      pref = nullptr;
+    }
+  }
+  mCJKPrefLangs.Clear();
+  mEmojiPrefFont = nullptr;
+
+  // Create a new FontPrefs and replace the existing one.
+  mFontPrefs = MakeUnique<FontPrefs>();
+}
+
+// Support for memory reporting
+
+// this is also used by subclasses that hold additional font tables
+/*static*/
+size_t gfxPlatformFontList::SizeOfFontFamilyTableExcludingThis(
+    const FontFamilyTable& aTable, MallocSizeOf aMallocSizeOf) {
+  return std::accumulate(
+      aTable.Keys().cbegin(), aTable.Keys().cend(),
+      aTable.ShallowSizeOfExcludingThis(aMallocSizeOf),
+      [&](size_t oldValue, const nsACString& key) {
+        // We don't count the size of the family here, because this is an
+        // *extra* reference to a family that will have already been counted in
+        // the main list.
+        return oldValue + key.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+      });
+}
+
+/*static*/
+size_t gfxPlatformFontList::SizeOfFontEntryTableExcludingThis(
+    const FontEntryTable& aTable, MallocSizeOf aMallocSizeOf) {
+  return std::accumulate(
+      aTable.Keys().cbegin(), aTable.Keys().cend(),
+      aTable.ShallowSizeOfExcludingThis(aMallocSizeOf),
+      [&](size_t oldValue, const nsACString& key) {
+        // The font itself is counted by its owning family; here we only care
+        // about the names stored in the hashtable keys.
+
+        return oldValue + key.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+      });
+}
+
+void gfxPlatformFontList::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
+                                                 FontListSizes* aSizes) const {
+  AutoLock lock(mLock);
+
+  aSizes->mFontListSize +=
+      mFontFamilies.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  for (const auto& entry : mFontFamilies) {
+    aSizes->mFontListSize +=
+        entry.GetKey().SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+    entry.GetData()->AddSizeOfIncludingThis(aMallocSizeOf, aSizes);
+  }
+
+  aSizes->mFontListSize +=
+      SizeOfFontFamilyTableExcludingThis(mOtherFamilyNames, aMallocSizeOf);
+
+  if (mExtraNames) {
+    aSizes->mFontListSize += SizeOfFontEntryTableExcludingThis(
+        mExtraNames->mFullnames, aMallocSizeOf);
+    aSizes->mFontListSize += SizeOfFontEntryTableExcludingThis(
+        mExtraNames->mPostscriptNames, aMallocSizeOf);
+  }
+
+  for (uint32_t i = eFontPrefLang_First;
+       i < eFontPrefLang_First + eFontPrefLang_Count; i++) {
+    auto& prefFontsLangGroup = mLangGroupPrefFonts[i];
+    for (const UniquePtr<PrefFontList>& pf : prefFontsLangGroup) {
+      if (pf) {
+        aSizes->mFontListSize += pf->ShallowSizeOfExcludingThis(aMallocSizeOf);
+      }
+    }
+  }
+
+  for (const auto& bitset : mCodepointsWithNoFonts) {
+    aSizes->mFontListSize += bitset.SizeOfExcludingThis(aMallocSizeOf);
+  }
+  aSizes->mFontListSize +=
+      mFontFamiliesToLoad.ShallowSizeOfExcludingThis(aMallocSizeOf);
+
+  aSizes->mFontListSize +=
+      mBadUnderlineFamilyNames.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  for (const auto& i : mBadUnderlineFamilyNames) {
+    aSizes->mFontListSize += i.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+  }
+
+  aSizes->mFontListSize +=
+      mSharedCmaps.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  for (const auto& entry : mSharedCmaps) {
+    aSizes->mCharMapsSize += entry.GetKey()->SizeOfIncludingThis(aMallocSizeOf);
+  }
+
+  aSizes->mFontListSize +=
+      mFontEntries.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  for (const auto& entry : mFontEntries.Values()) {
+    if (entry) {
+      entry->AddSizeOfIncludingThis(aMallocSizeOf, aSizes);
+    }
+  }
+
+  if (SharedFontList()) {
+    aSizes->mFontListSize +=
+        SharedFontList()->SizeOfIncludingThis(aMallocSizeOf);
+    if (XRE_IsParentProcess()) {
+      aSizes->mSharedSize += SharedFontList()->AllocatedShmemSize();
+    }
+  }
+}
+
+void gfxPlatformFontList::AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf,
+                                                 FontListSizes* aSizes) const {
+  aSizes->mFontListSize += aMallocSizeOf(this);
+  AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
+}
+
+void gfxPlatformFontList::InitOtherFamilyNamesInternal(
+    bool aDeferOtherFamilyNamesLoading) {
+  if (mOtherFamilyNamesInitialized) {
+    return;
+  }
+
+  AutoLock lock(mLock);
+
+  if (aDeferOtherFamilyNamesLoading) {
+    TimeStamp start = TimeStamp::Now();
+    bool timedOut = false;
+
+    auto list = SharedFontList();
+    if (list) {
+      // If the gfxFontInfoLoader task is not yet running, kick it off now so
+      // that it will load remaining names etc as soon as idle time permits.
+      if (mState == stateInitial || mState == stateTimerOnDelay) {
+        StartLoader(0);
+        timedOut = true;
+      }
+    } else {
+      for (const RefPtr<gfxFontFamily>& family : mFontFamilies.Values()) {
+        family->ReadOtherFamilyNames(this);
+        TimeDuration elapsed = TimeStamp::Now() - start;
+        if (elapsed.ToMilliseconds() > OTHERNAMES_TIMEOUT) {
+          timedOut = true;
+          break;
+        }
+      }
+    }
+
+    if (!timedOut) {
+      mOtherFamilyNamesInitialized = true;
+      CancelInitOtherFamilyNamesTask();
+    }
+    TimeStamp end = TimeStamp::Now();
+    Telemetry::AccumulateTimeDelta(Telemetry::FONTLIST_INITOTHERFAMILYNAMES,
+                                   start, end);
+
+    if (LOG_FONTINIT_ENABLED()) {
+      TimeDuration elapsed = end - start;
+      LOG_FONTINIT(("(fontinit) InitOtherFamilyNames took %8.2f ms %s",
+                    elapsed.ToMilliseconds(), (timedOut ? "timeout" : "")));
+    }
+  } else {
+    TimeStamp start = TimeStamp::Now();
+
+    auto list = SharedFontList();
+    if (list) {
+      for (auto& f : mozilla::Range<fontlist::Family>(list->Families(),
+                                                      list->NumFamilies())) {
+        ReadFaceNamesForFamily(&f, false);
+      }
+    } else {
+      for (const RefPtr<gfxFontFamily>& family : mFontFamilies.Values()) {
+        family->ReadOtherFamilyNames(this);
+      }
+    }
+
+    mOtherFamilyNamesInitialized = true;
+    CancelInitOtherFamilyNamesTask();
+
+    TimeStamp end = TimeStamp::Now();
+    Telemetry::AccumulateTimeDelta(
+        Telemetry::FONTLIST_INITOTHERFAMILYNAMES_NO_DEFERRING, start, end);
+
+    if (LOG_FONTINIT_ENABLED()) {
+      TimeDuration elapsed = end - start;
+      LOG_FONTINIT(
+          ("(fontinit) InitOtherFamilyNames without deferring took %8.2f ms",
+           elapsed.ToMilliseconds()));
+    }
+  }
+}
+
+void gfxPlatformFontList::CancelInitOtherFamilyNamesTask() {
+  if (mPendingOtherFamilyNameTask) {
+    mPendingOtherFamilyNameTask->Cancel();
+    mPendingOtherFamilyNameTask = nullptr;
+  }
+  auto list = SharedFontList();
+  if (list && XRE_IsParentProcess()) {
+    bool forceReflow = false;
+    if (!mAliasTable.IsEmpty()) {
+      list->SetAliases(mAliasTable);
+      mAliasTable.Clear();
+      forceReflow = true;
+    }
+    if (mLocalNameTable.Count()) {
+      list->SetLocalNames(mLocalNameTable);
+      mLocalNameTable.Clear();
+      forceReflow = true;
+    }
+    if (forceReflow) {
+      dom::ContentParent::BroadcastFontListChanged();
+    }
+  }
+}
+
+void gfxPlatformFontList::ShareFontListShmBlockToProcess(
+    uint32_t aGeneration, uint32_t aIndex, base::ProcessId aPid,
+    base::SharedMemoryHandle* aOut) {
+  auto list = SharedFontList();
+  if (!list) {
+    return;
+  }
+  if (!aGeneration || list->GetGeneration() == aGeneration) {
+    list->ShareShmBlockToProcess(aIndex, aPid, aOut);
+  } else {
+    *aOut = base::SharedMemory::NULLHandle();
+  }
+}
+
+void gfxPlatformFontList::ShareFontListToProcess(
+    nsTArray<base::SharedMemoryHandle>* aBlocks, base::ProcessId aPid) {
+  auto list = SharedFontList();
+  if (list) {
+    list->ShareBlocksToProcess(aBlocks, aPid);
+  }
+}
+
+base::SharedMemoryHandle gfxPlatformFontList::ShareShmBlockToProcess(
+    uint32_t aIndex, base::ProcessId aPid) {
+  MOZ_RELEASE_ASSERT(SharedFontList());
+  return SharedFontList()->ShareBlockToProcess(aIndex, aPid);
+}
+
+void gfxPlatformFontList::ShmBlockAdded(uint32_t aGeneration, uint32_t aIndex,
+                                        base::SharedMemoryHandle aHandle) {
+  if (SharedFontList()) {
+    SharedFontList()->ShmBlockAdded(aGeneration, aIndex, std::move(aHandle));
+  }
+}
+
+void gfxPlatformFontList::InitializeFamily(uint32_t aGeneration,
+                                           uint32_t aFamilyIndex,
+                                           bool aLoadCmaps) {
+  auto list = SharedFontList();
+  MOZ_ASSERT(list);
+  if (!list) {
+    return;
+  }
+  if (list->GetGeneration() != aGeneration) {
+    return;
+  }
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return;
+  }
+  if (aFamilyIndex >= list->NumFamilies()) {
+    return;
+  }
+  fontlist::Family* family = list->Families() + aFamilyIndex;
+  if (!family->IsInitialized() || aLoadCmaps) {
+    Unused << InitializeFamily(family, aLoadCmaps);
+  }
+}
+
+void gfxPlatformFontList::SetCharacterMap(uint32_t aGeneration,
+                                          const fontlist::Pointer& aFacePtr,
+                                          const gfxSparseBitSet& aMap) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  auto list = SharedFontList();
+  MOZ_ASSERT(list);
+  if (!list) {
+    return;
+  }
+  if (list->GetGeneration() != aGeneration) {
+    return;
+  }
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return;
+  }
+  fontlist::Face* face = static_cast<fontlist::Face*>(aFacePtr.ToPtr(list));
+  if (face) {
+    face->mCharacterMap = GetShmemCharMap(&aMap);
+  }
+}
+
+void gfxPlatformFontList::SetupFamilyCharMap(
+    uint32_t aGeneration, const fontlist::Pointer& aFamilyPtr) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  auto list = SharedFontList();
+  MOZ_ASSERT(list);
+  if (!list) {
+    return;
+  }
+  if (list->GetGeneration() != aGeneration) {
+    return;
+  }
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return;
+  }
+
+  // aFamilyPtr was passed from a content process which may not be trusted,
+  // so we cannot assume it is valid or safe to use. If the Pointer value is
+  // bad, we must not crash or do anything bad, just bail out.
+  // (In general, if the child process was trying to use an invalid pointer it
+  // should have hit the MOZ_DIAGNOSTIC_ASSERT in FontList::ToSharedPointer
+  // rather than passing a null or bad pointer to the parent.)
+
+  auto* family = static_cast<fontlist::Family*>(aFamilyPtr.ToPtr(list));
+  if (!family) {
+    // Unable to resolve to a native pointer (or it was null).
+    NS_WARNING("unexpected null Family pointer");
+    return;
+  }
+
+  // Validate the pointer before trying to use it: check that it points to a
+  // correctly-aligned offset within the Families() or AliasFamilies() array.
+  // We just assert (in debug builds only) on failure, and return safely.
+  // A misaligned pointer here would indicate a buggy (or compromised) child
+  // process, but crashing the parent would be unnecessary and does not yield
+  // any useful insight.
+  if (family >= list->Families() &&
+      family < list->Families() + list->NumFamilies()) {
+    size_t offset = (char*)family - (char*)list->Families();
+    if (offset % sizeof(fontlist::Family) != 0) {
+      MOZ_ASSERT(false, "misaligned Family pointer");
+      return;
+    }
+  } else if (family >= list->AliasFamilies() &&
+             family < list->AliasFamilies() + list->NumAliases()) {
+    size_t offset = (char*)family - (char*)list->AliasFamilies();
+    if (offset % sizeof(fontlist::Family) != 0) {
+      MOZ_ASSERT(false, "misaligned Family pointer");
+      return;
+    }
+  } else {
+    MOZ_ASSERT(false, "not a valid Family or AliasFamily pointer");
+    return;
+  }
+
+  family->SetupFamilyCharMap(list);
+}
+
+bool gfxPlatformFontList::InitOtherFamilyNames(uint32_t aGeneration,
+                                               bool aDefer) {
+  auto list = SharedFontList();
+  MOZ_ASSERT(list);
+  if (!list) {
+    return false;
+  }
+  if (list->GetGeneration() != aGeneration) {
+    return false;
+  }
+  if (AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed)) {
+    return false;
+  }
+  return InitOtherFamilyNames(aDefer);
+}
+
+uint32_t gfxPlatformFontList::GetGeneration() const {
+  return SharedFontList() ? SharedFontList()->GetGeneration() : 0;
+}
+
+gfxPlatformFontList::FontPrefs::FontPrefs() {
+  // This must be created on the main thread, so that we can safely use the
+  // Preferences service. Once created, it can be read from any thread.
+  MOZ_ASSERT(NS_IsMainThread());
+  Init();
+}
+
+void gfxPlatformFontList::FontPrefs::Init() {
+  nsIPrefBranch* prefRootBranch = Preferences::GetRootBranch();
+  if (!prefRootBranch) {
+    return;
+  }
+  nsTArray<nsCString> prefNames;
+  if (NS_SUCCEEDED(prefRootBranch->GetChildList(kNamePrefix, prefNames))) {
+    for (auto& prefName : prefNames) {
+      nsAutoCString value;
+      if (NS_SUCCEEDED(Preferences::GetCString(prefName.get(), value))) {
+        nsAutoCString pref(Substring(prefName, sizeof(kNamePrefix) - 1));
+        mFontName.InsertOrUpdate(pref, value);
+      }
+    }
+  }
+  if (NS_SUCCEEDED(prefRootBranch->GetChildList(kNameListPrefix, prefNames))) {
+    for (auto& prefName : prefNames) {
+      nsAutoCString value;
+      if (NS_SUCCEEDED(Preferences::GetCString(prefName.get(), value))) {
+        nsAutoCString pref(Substring(prefName, sizeof(kNameListPrefix) - 1));
+        mFontNameList.InsertOrUpdate(pref, value);
+      }
+    }
+  }
+  mEmojiHasUserValue = Preferences::HasUserValue("font.name-list.emoji");
+}
+
+bool gfxPlatformFontList::FontPrefs::LookupName(const nsACString& aPref,
+                                                nsACString& aValue) const {
+  if (const auto& value = mFontName.Lookup(aPref)) {
+    aValue = *value;
+    return true;
+  }
+  return false;
+}
+
+bool gfxPlatformFontList::FontPrefs::LookupNameList(const nsACString& aPref,
+                                                    nsACString& aValue) const {
+  if (const auto& value = mFontNameList.Lookup(aPref)) {
+    aValue = *value;
+    return true;
+  }
+  return false;
+}
+
+#undef LOG
+#undef LOG_ENABLED