dom/encoding/EncodingUtils.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "mozilla/dom/EncodingUtils.h"
   6
   7 #include "mozilla/ArrayUtils.h" // ArrayLength
   8 #include "nsUConvPropertySearch.h"
   9 #include "nsIUnicodeDecoder.h"
  10 #include "nsIUnicodeEncoder.h"
  11 #include "nsComponentManagerUtils.h"
  12
  13 namespace mozilla {
  14 namespace dom {
  15
  16 static const char* labelsEncodings[][3] = {
  17 #include "labelsencodings.properties.h"
  18 };
  19
  20 static const char* encodingsGroups[][3] = {
  21 #include "encodingsgroups.properties.h"
  22 };
  23
  24 bool
  25 EncodingUtils::FindEncodingForLabel(const nsACString& aLabel,
  26                                     nsACString& aOutEncoding)
  27 {
  28   // Save aLabel first because it may refer the same string as aOutEncoding.
  29   nsCString label(aLabel);
  30
  31   EncodingUtils::TrimSpaceCharacters(label);
  32   if (label.IsEmpty()) {
  33     aOutEncoding.Truncate();
  34     return false;
  35   }
  36
  37   ToLowerCase(label);
  38   return NS_SUCCEEDED(nsUConvPropertySearch::SearchPropertyValue(
  39       labelsEncodings, ArrayLength(labelsEncodings), label, aOutEncoding));
  40 }
  41
  42 bool
  43 EncodingUtils::FindEncodingForLabelNoReplacement(const nsACString& aLabel,
  44                                                  nsACString& aOutEncoding)
  45 {
  46   if(!FindEncodingForLabel(aLabel, aOutEncoding)) {
  47     return false;
  48   }
  49   if (aOutEncoding.EqualsLiteral("replacement")) {
  50     aOutEncoding.Truncate();
  51     return false;
  52   }
  53   return true;
  54 }
  55
  56 bool
  57 EncodingUtils::IsAsciiCompatible(const nsACString& aPreferredName)
  58 {
  59   return !(aPreferredName.LowerCaseEqualsLiteral("utf-16") ||
  60            aPreferredName.LowerCaseEqualsLiteral("utf-16be") ||
  61            aPreferredName.LowerCaseEqualsLiteral("utf-16le") ||
  62            aPreferredName.LowerCaseEqualsLiteral("replacement") ||
  63            aPreferredName.LowerCaseEqualsLiteral("hz-gb-2312") ||
  64            aPreferredName.LowerCaseEqualsLiteral("utf-7") ||
  65            aPreferredName.LowerCaseEqualsLiteral("x-imap4-modified-utf7"));
  66 }
  67
  68 already_AddRefed<nsIUnicodeDecoder>
  69 EncodingUtils::DecoderForEncoding(const nsACString& aEncoding)
  70 {
  71   nsAutoCString contractId(NS_UNICODEDECODER_CONTRACTID_BASE);
  72   contractId.Append(aEncoding);
  73
  74   nsCOMPtr<nsIUnicodeDecoder> decoder = do_CreateInstance(contractId.get());
  75   MOZ_ASSERT(decoder, "Tried to create decoder for unknown encoding.");
  76   return decoder.forget();
  77 }
  78
  79 already_AddRefed<nsIUnicodeEncoder>
  80 EncodingUtils::EncoderForEncoding(const nsACString& aEncoding)
  81 {
  82   nsAutoCString contractId(NS_UNICODEENCODER_CONTRACTID_BASE);
  83   contractId.Append(aEncoding);
  84
  85   nsCOMPtr<nsIUnicodeEncoder> encoder = do_CreateInstance(contractId.get());
  86   MOZ_ASSERT(encoder, "Tried to create encoder for unknown encoding.");
  87   return encoder.forget();
  88 }
  89
  90 void
  91 EncodingUtils::LangGroupForEncoding(const nsACString& aEncoding,
  92                                     nsACString& aOutGroup)
  93 {
  94   if (NS_FAILED(nsUConvPropertySearch::SearchPropertyValue(
  95       encodingsGroups, ArrayLength(encodingsGroups), aEncoding, aOutGroup))) {
  96     aOutGroup.AssignLiteral("x-unicode");
  97   }
  98 }
  99
 100 } // namespace dom
 101 } // namespace mozilla