summaryrefslogtreecommitdiff
path: root/dom/encoding/FallbackEncoding.cpp
blob: 93fe0f8cb9aeee042b97315650275b80b793ff08 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/* -*- 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/dom/EncodingUtils.h"
#include "nsUConvPropertySearch.h"
#include "nsIChromeRegistry.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"

namespace mozilla {
namespace dom {

static const nsUConvProp localesFallbacks[] = {
#include "localesfallbacks.properties.h"
};

static const nsUConvProp domainsFallbacks[] = {
#include "domainsfallbacks.properties.h"
};

static const nsUConvProp nonParticipatingDomains[] = {
#include "nonparticipatingdomains.properties.h"
};

FallbackEncoding* FallbackEncoding::sInstance = nullptr;
bool FallbackEncoding::sGuessFallbackFromTopLevelDomain = true;

FallbackEncoding::FallbackEncoding()
{
  MOZ_COUNT_CTOR(FallbackEncoding);
  MOZ_ASSERT(!FallbackEncoding::sInstance,
             "Singleton already exists.");
}

FallbackEncoding::~FallbackEncoding()
{
  MOZ_COUNT_DTOR(FallbackEncoding);
}

void
FallbackEncoding::Get(nsACString& aFallback)
{
  if (!mFallback.IsEmpty()) {
    aFallback = mFallback;
    return;
  }

  const nsAdoptingCString& override =
    Preferences::GetCString("intl.charset.fallback.override");
  // Don't let the user break things by setting the override to unreasonable
  // values via about:config
  if (!EncodingUtils::FindEncodingForLabel(override, mFallback) ||
      !EncodingUtils::IsAsciiCompatible(mFallback) ||
      mFallback.EqualsLiteral("UTF-8")) {
    mFallback.Truncate();
  }

  if (!mFallback.IsEmpty()) {
    aFallback = mFallback;
    return;
  }

  nsAutoCString locale;
  nsCOMPtr<nsIXULChromeRegistry> registry =
    mozilla::services::GetXULChromeRegistryService();
  if (registry) {
    registry->GetSelectedLocale(NS_LITERAL_CSTRING("global"), false, 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.AssignLiteral("Big5");
    aFallback = mFallback;
    return;
  }

  // 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);
  }

  if (NS_FAILED(nsUConvPropertySearch::SearchPropertyValue(
      localesFallbacks, ArrayLength(localesFallbacks), locale, mFallback))) {
    mFallback.AssignLiteral("windows-1252");
  }

  aFallback = mFallback;
}

void
FallbackEncoding::FromLocale(nsACString& aFallback)
{
  MOZ_ASSERT(FallbackEncoding::sInstance,
             "Using uninitialized fallback cache.");
  FallbackEncoding::sInstance->Get(aFallback);
}

// PrefChangedFunc
void
FallbackEncoding::PrefChanged(const char*, void*)
{
  MOZ_ASSERT(FallbackEncoding::sInstance,
             "Pref callback called with null fallback cache.");
  FallbackEncoding::sInstance->Invalidate();
}

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::RegisterCallback(FallbackEncoding::PrefChanged,
                                "general.useragent.locale",
                                nullptr);
  Preferences::AddBoolVarCache(&sGuessFallbackFromTopLevelDomain,
                               "intl.charset.fallback.tld");
}

void
FallbackEncoding::Shutdown()
{
  MOZ_ASSERT(FallbackEncoding::sInstance,
             "Releasing non-existent fallback cache.");
  delete FallbackEncoding::sInstance;
  FallbackEncoding::sInstance = nullptr;
}

bool
FallbackEncoding::IsParticipatingTopLevelDomain(const nsACString& aTLD)
{
  nsAutoCString dummy;
  return NS_FAILED(nsUConvPropertySearch::SearchPropertyValue(
      nonParticipatingDomains,
      ArrayLength(nonParticipatingDomains),
      aTLD,
      dummy));
}

void
FallbackEncoding::FromTopLevelDomain(const nsACString& aTLD,
                                     nsACString& aFallback)
{
  if (NS_FAILED(nsUConvPropertySearch::SearchPropertyValue(
      domainsFallbacks, ArrayLength(domainsFallbacks), aTLD, aFallback))) {
    aFallback.AssignLiteral("windows-1252");
  }
}

} // namespace dom
} // namespace mozilla