gecko-dev/dom/encoding/FallbackEncoding.cpp

200 строки
5.7 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/dom/FallbackEncoding.h"
#include "mozilla/Encoding.h"
#include "mozilla/intl/LocaleService.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"
#include "nsIObserverService.h"
#include "nsUConvPropertySearch.h"
using mozilla::intl::LocaleService;
namespace mozilla {
namespace dom {
struct EncodingProp
{
const char* const mKey;
NotNull<const Encoding*> mValue;
};
template <int32_t N>
static NotNull<const Encoding*>
SearchEncodingProp(const EncodingProp (&aProperties)[N],
const nsACString& aKey)
{
const nsCString& flat = PromiseFlatCString(aKey);
size_t index;
if (!BinarySearchIf(aProperties, 0, ArrayLength(aProperties),
[&flat](const EncodingProp& aProperty)
{ return flat.Compare(aProperty.mKey); }, &index)) {
return WINDOWS_1252_ENCODING;
}
return aProperties[index].mValue;
}
static const EncodingProp localesFallbacks[] = {
#include "localesfallbacks.properties.h"
};
static const EncodingProp domainsFallbacks[] = {
#include "domainsfallbacks.properties.h"
};
static constexpr nsUConvProp nonParticipatingDomains[] = {
#include "nonparticipatingdomains.properties.h"
};
NS_IMPL_ISUPPORTS(FallbackEncoding, nsIObserver)
FallbackEncoding* FallbackEncoding::sInstance = nullptr;
bool FallbackEncoding::sGuessFallbackFromTopLevelDomain = true;
bool FallbackEncoding::sFallbackToUTF8ForFile = false;
FallbackEncoding::FallbackEncoding()
: mFallback(nullptr)
{
MOZ_ASSERT(!FallbackEncoding::sInstance,
"Singleton already exists.");
}
NotNull<const Encoding*>
FallbackEncoding::Get()
{
if (mFallback) {
return WrapNotNull(mFallback);
}
nsAutoCString override;
Preferences::GetCString("intl.charset.fallback.override", override);
// Don't let the user break things by setting the override to unreasonable
// values via about:config
auto encoding = Encoding::ForLabel(override);
if (!encoding || !encoding->IsAsciiCompatible() ||
encoding == UTF_8_ENCODING) {
mFallback = nullptr;
} else {
mFallback = encoding;
}
if (mFallback) {
return WrapNotNull(mFallback);
}
nsAutoCString locale;
LocaleService::GetInstance()->GetAppLocaleAsLangTag(locale);
// Let's lower case the string just in case unofficial language packs
// don't stick to conventions.
ToLowerCase(locale); // ASCII lowercasing with CString input!
// Special case Traditional Chinese before throwing away stuff after the
// language itself. Today we only ship zh-TW, but be defensive about
// possible future values.
if (locale.EqualsLiteral("zh-tw") ||
locale.EqualsLiteral("zh-hk") ||
locale.EqualsLiteral("zh-mo") ||
locale.EqualsLiteral("zh-hant")) {
mFallback = BIG5_ENCODING;
return WrapNotNull(mFallback);
}
// Throw away regions and other variants to accommodate weird stuff seen
// in telemetry--apparently unofficial language packs.
int32_t index = locale.FindChar('-');
if (index >= 0) {
locale.Truncate(index);
}
auto fallback = SearchEncodingProp(localesFallbacks, locale);
mFallback = fallback;
return fallback;
}
NotNull<const Encoding*>
FallbackEncoding::FromLocale()
{
MOZ_ASSERT(FallbackEncoding::sInstance,
"Using uninitialized fallback cache.");
return FallbackEncoding::sInstance->Get();
}
// PrefChangedFunc
void
FallbackEncoding::PrefChanged(const char*, void*)
{
MOZ_ASSERT(FallbackEncoding::sInstance,
"Pref callback called with null fallback cache.");
FallbackEncoding::sInstance->Invalidate();
}
NS_IMETHODIMP
FallbackEncoding::Observe(nsISupports *aSubject, const char *aTopic,
const char16_t *aData)
{
MOZ_ASSERT(FallbackEncoding::sInstance,
"Observe callback called with null fallback cache.");
FallbackEncoding::sInstance->Invalidate();
return NS_OK;
}
void
FallbackEncoding::Initialize()
{
MOZ_ASSERT(!FallbackEncoding::sInstance,
"Initializing pre-existing fallback cache.");
FallbackEncoding::sInstance = new FallbackEncoding;
Preferences::RegisterCallback(FallbackEncoding::PrefChanged,
"intl.charset.fallback.override",
nullptr);
Preferences::AddBoolVarCache(&sGuessFallbackFromTopLevelDomain,
"intl.charset.fallback.tld");
Preferences::AddBoolVarCache(&sFallbackToUTF8ForFile,
"intl.charset.fallback.utf8_for_file");
nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
if (obs) {
obs->AddObserver(sInstance, "intl:requested-locales-changed", true);
}
}
void
FallbackEncoding::Shutdown()
{
MOZ_ASSERT(FallbackEncoding::sInstance,
"Releasing non-existent fallback cache.");
nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
if (obs) {
obs->RemoveObserver(sInstance, "intl:requested-locales-changed");
}
delete FallbackEncoding::sInstance;
FallbackEncoding::sInstance = nullptr;
}
bool
FallbackEncoding::IsParticipatingTopLevelDomain(const nsACString& aTLD)
{
nsAutoCString dummy;
return NS_FAILED(nsUConvPropertySearch::SearchPropertyValue(
nonParticipatingDomains,
ArrayLength(nonParticipatingDomains),
aTLD,
dummy));
}
NotNull<const Encoding*>
FallbackEncoding::FromTopLevelDomain(const nsACString& aTLD)
{
return SearchEncodingProp(domainsFallbacks, aTLD);
}
} // namespace dom
} // namespace mozilla