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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef mozilla_StaticPresData_h
#define mozilla_StaticPresData_h
#include "mozilla/StaticPtr.h"
#include "mozilla/UniquePtr.h"
#include "nsCoord.h"
#include "nsCOMPtr.h"
#include "nsFont.h"
#include "nsAtom.h"
#include "nsLanguageAtomService.h"
namespace mozilla {
struct LangGroupFontPrefs {
// Font sizes default to zero; they will be set in GetFontPreferences
: mLangGroup(nullptr),
mDefaultVariableFont(StyleGenericFontFamily::Serif, {0}),
mDefaultSerifFont(StyleGenericFontFamily::Serif, {0}),
mDefaultSansSerifFont(StyleGenericFontFamily::SansSerif, {0}),
mDefaultMonospaceFont(StyleGenericFontFamily::Monospace, {0}),
mDefaultCursiveFont(StyleGenericFontFamily::Cursive, {0}),
mDefaultFantasyFont(StyleGenericFontFamily::Fantasy, {0}),
mDefaultSystemUiFont(StyleGenericFontFamily::SystemUi, {0}) {}
StyleGenericFontFamily GetDefaultGeneric() const {
void Reset() {
// Throw away any other LangGroupFontPrefs objects:
mNext = nullptr;
// Make GetFontPreferences reinitialize mLangGroupFontPrefs:
mLangGroup = nullptr;
// Initialize this with the data for a given language
void Initialize(nsStaticAtom* aLangGroupAtom);
* Get the default font for the given language and generic font ID.
* aLanguage may not be nullptr.
* This object is read-only, you must copy the font to modify it.
* For aFontID corresponding to a CSS Generic, the nsFont returned has
* its name set to that generic font's name, and its size set to
* the user's preference for font size for that generic and the
* given language.
const nsFont* GetDefaultFont(StyleGenericFontFamily aFamily) const {
switch (aFamily) {
// Special (our default variable width font and fixed width font)
case StyleGenericFontFamily::None:
return &mDefaultVariableFont;
// CSS
case StyleGenericFontFamily::Serif:
return &mDefaultSerifFont;
case StyleGenericFontFamily::SansSerif:
return &mDefaultSansSerifFont;
case StyleGenericFontFamily::Monospace:
return &mDefaultMonospaceFont;
case StyleGenericFontFamily::Cursive:
return &mDefaultCursiveFont;
case StyleGenericFontFamily::Fantasy:
return &mDefaultFantasyFont;
case StyleGenericFontFamily::SystemUi:
return &mDefaultSystemUiFont;
case StyleGenericFontFamily::MozEmoji:
// This shouldn't appear in font family names.
MOZ_ASSERT_UNREACHABLE("invalid font id");
return nullptr;
nsStaticAtom* mLangGroup;
Length mMinimumFontSize;
nsFont mDefaultVariableFont;
nsFont mDefaultSerifFont;
nsFont mDefaultSansSerifFont;
nsFont mDefaultMonospaceFont;
nsFont mDefaultCursiveFont;
nsFont mDefaultFantasyFont;
nsFont mDefaultSystemUiFont;
UniquePtr<LangGroupFontPrefs> mNext;
* Some functionality that has historically lived on nsPresContext does not
* actually need to be per-document. This singleton class serves as a host
* for that functionality. We delegate to it from nsPresContext where
* appropriate, and use it standalone in some cases as well.
class StaticPresData {
// Initialization and shutdown of the singleton. Called exactly once.
static void Init();
static void Shutdown();
// Gets an instance of the singleton. Infallible between the calls to Init
// and Shutdown.
static StaticPresData* Get();
* Given a language, get the language group name, which can
* be used as an argument to LangGroupFontPrefs::Initialize()
* aNeedsToCache is used for two things. If null, it indicates that
* the nsLanguageAtomService is safe to cache the result of the
* language group lookup, either because we're on the main thread,
* or because we're on a style worker thread but the font lock has
* been acquired. If non-null, it indicates that it's not safe to
* cache the result of the language group lookup (because we're on
* a style worker thread without the lock acquired). In this case,
* GetLanguageGroup will store true in *aNeedsToCache true if we
* would have cached the result of a new lookup, and false if we
* were able to use an existing cached result. Thus, callers that
* get a true *aNeedsToCache outparam value should make an effort
* to re-call GetLanguageGroup when it is safe to cache, to avoid
* recomputing the language group again later.
nsStaticAtom* GetLangGroup(nsAtom* aLanguage,
bool* aNeedsToCache = nullptr) const;
* Same as GetLangGroup, but will not cache the result
nsStaticAtom* GetUncachedLangGroup(nsAtom* aLanguage) const;
* Fetch the user's font preferences for the given aLanguage's
* langugage group.
* The original code here is pretty old, and includes an optimization
* whereby language-specific prefs are read per-document, and the
* results are stored in a linked list, which is assumed to be very short
* since most documents only ever use one language.
* Storing this per-session rather than per-document would almost certainly
* be fine. But just to be on the safe side, we leave the old mechanism as-is,
* with an additional per-session cache that new callers can use if they don't
* have a PresContext.
* See comment on GetLangGroup for the usage of aNeedsToCache.
const LangGroupFontPrefs* GetFontPrefsForLang(nsAtom* aLanguage,
bool* aNeedsToCache = nullptr);
const nsFont* GetDefaultFont(uint8_t aFontID, nsAtom* aLanguage,
const LangGroupFontPrefs* aPrefs) const;
void InvalidateFontPrefs() { mLangGroupFontPrefs.Reset(); }
// Private constructor/destructor, to prevent other code from inadvertently
// instantiating or deleting us. (Though we need to declare StaticAutoPtr as
// a friend to give it permission.)
~StaticPresData() = default;
friend class StaticAutoPtr<StaticPresData>;
nsLanguageAtomService* mLangService;
LangGroupFontPrefs mLangGroupFontPrefs;
} // namespace mozilla
#endif // mozilla_StaticPresData_h