accessible/atk/DOMtoATK.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "DOMtoATK.h"
   8 #include "nsUTF8Utils.h"
   9
  10 namespace mozilla {
  11 namespace a11y {
  12
  13 namespace DOMtoATK {
  14
  15 void AddBOMs(nsACString& aDest, const nsACString& aSource) {
  16   uint32_t destlength = 0;
  17
  18   // First compute how much room we will need.
  19   for (uint32_t srci = 0; srci < aSource.Length();) {
  20     int bytes = UTF8traits::bytes(aSource[srci]);
  21     if (bytes >= 4) {
  22       // Non-BMP character, will add a BOM after it.
  23       destlength += 3;
  24     }
  25     // Skip whole character encoding.
  26     srci += bytes;
  27     destlength += bytes;
  28   }
  29
  30   uint32_t desti = 0;  // Index within aDest.
  31
  32   // Add BOMs after non-BMP characters.
  33   aDest.SetLength(destlength);
  34   for (uint32_t srci = 0; srci < aSource.Length();) {
  35     uint32_t bytes = UTF8traits::bytes(aSource[srci]);
  36
  37     MOZ_ASSERT(bytes <= aSource.Length() - srci,
  38                "We should have the whole sequence");
  39
  40     // Copy whole sequence.
  41     aDest.Replace(desti, bytes, Substring(aSource, srci, bytes));
  42     desti += bytes;
  43     srci += bytes;
  44
  45     if (bytes >= 4) {
  46       // More than 4 bytes in UTF-8 encoding exactly means more than 16 encoded
  47       // bits.  This is thus a non-BMP character which needed a surrogate
  48       // pair to get encoded in UTF-16, add a BOM after it.
  49
  50       // And add a BOM after it.
  51       aDest.Replace(desti, 3, "\xEF\xBB\xBF");
  52       desti += 3;
  53     }
  54   }
  55   MOZ_ASSERT(desti == destlength,
  56              "Incoherency between computed length"
  57              "and actually translated length");
  58 }
  59
  60 void ATKStringConverterHelper::AdjustOffsets(gint* aStartOffset,
  61                                              gint* aEndOffset, gint count) {
  62   MOZ_ASSERT(!mAdjusted,
  63              "DOMtoATK::ATKStringConverterHelper::AdjustOffsets needs to be "
  64              "called only once");
  65
  66   if (*aStartOffset > 0) {
  67     (*aStartOffset)--;
  68     mStartShifted = true;
  69   }
  70
  71   if (*aEndOffset >= 0 && *aEndOffset < count) {
  72     (*aEndOffset)++;
  73     mEndShifted = true;
  74   }
  75
  76 #ifdef DEBUG
  77   mAdjusted = true;
  78 #endif
  79 }
  80
  81 gchar* ATKStringConverterHelper::FinishUTF16toUTF8(nsCString& aStr) {
  82   int skip = 0;
  83
  84   if (mStartShifted) {
  85     // AdjustOffsets added a leading character.
  86
  87     MOZ_ASSERT(aStr.Length() > 0, "There should be a leading character");
  88     MOZ_ASSERT(
  89         static_cast<int>(aStr.Length()) >= UTF8traits::bytes(aStr.CharAt(0)),
  90         "The leading character should be complete");
  91
  92     // drop first character
  93     skip = UTF8traits::bytes(aStr.CharAt(0));
  94   }
  95
  96   if (mEndShifted) {
  97     // AdjustOffsets added a trailing character.
  98
  99     MOZ_ASSERT(aStr.Length() > 0, "There should be a trailing character");
 100
 101     int trail = -1;
 102     // Find beginning of last character.
 103     for (trail = aStr.Length() - 1; trail >= 0; trail--) {
 104       if (!UTF8traits::isInSeq(aStr.CharAt(trail))) {
 105         break;
 106       }
 107     }
 108     MOZ_ASSERT(trail >= 0,
 109                "There should be at least a whole trailing character");
 110     MOZ_ASSERT(trail + UTF8traits::bytes(aStr.CharAt(trail)) ==
 111                    static_cast<int>(aStr.Length()),
 112                "The trailing character should be complete");
 113
 114     // Drop the last character.
 115     aStr.Truncate(trail);
 116   }
 117
 118   // copy and return, libspi will free it
 119   return g_strdup(aStr.get() + skip);
 120 }
 121
 122 gchar* ATKStringConverterHelper::ConvertAdjusted(const nsAString& aStr) {
 123   MOZ_ASSERT(mAdjusted,
 124              "DOMtoATK::ATKStringConverterHelper::AdjustOffsets needs to be "
 125              "called before ATKStringConverterHelper::ConvertAdjusted");
 126
 127   NS_ConvertUTF16toUTF8 cautoStr(aStr);
 128   if (!cautoStr.get()) {
 129     return nullptr;
 130   }
 131
 132   nsAutoCString cautoStrBOMs;
 133   AddBOMs(cautoStrBOMs, cautoStr);
 134   return FinishUTF16toUTF8(cautoStrBOMs);
 135 }
 136
 137 gchar* Convert(const nsAString& aStr) {
 138   NS_ConvertUTF16toUTF8 cautoStr(aStr);
 139   if (!cautoStr.get()) {
 140     return nullptr;
 141   }
 142
 143   nsAutoCString cautoStrBOMs;
 144   AddBOMs(cautoStrBOMs, cautoStr);
 145   return g_strdup(cautoStrBOMs.get());
 146 }
 147
 148 void ConvertTexttoAsterisks(nsAString& aString) {
 149   for (uint32_t i = 0; i < aString.Length(); i++) {
 150     aString.ReplaceLiteral(i, 1, u"*");
 151   }
 152 }
 153
 154 }  // namespace DOMtoATK
 155
 156 }  // namespace a11y
 157 }  // namespace mozilla