1 files changed, 86 insertions, 0 deletions
diff --git a/netwerk/dns/IDNBlocklistUtils.cpp b/netwerk/dns/IDNBlocklistUtils.cpp
new file mode 100644
index 0000000000..92c73d0997
--- /dev/null
+++ b/netwerk/dns/IDNBlocklistUtils.cpp
@@ -0,0 +1,86 @@
+/* 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 "IDNBlocklistUtils.h"
+
+#include "mozilla/Preferences.h"
+#include "nsStringFwd.h"
+
+namespace mozilla {
+namespace net {
+
+static constexpr char16_t sBlocklistPairs[][2] = {
+#include "IDNCharacterBlocklist.inc"
+};
+
+void RemoveCharFromBlocklist(char16_t aChar,
+                             nsTArray<BlocklistRange>& aBlocklist) {
+  auto pos = aBlocklist.BinaryIndexOf(aChar, BlocklistPairToCharComparator());
+  if (pos == nsTArray<BlocklistRange>::NoIndex) {
+    return;
+  }
+
+  auto& pair = aBlocklist[pos];
+
+  // If the matched range has a length of one, we can just remove it
+  if (pair.second == pair.first) {
+    aBlocklist.RemoveElementAt(pos);
+    return;
+  }
+
+  // If the character matches the first element in the range, just update
+  // the range.
+  if (aChar == pair.first) {
+    pair.first = pair.first + 1;
+    return;
+  }
+
+  // Also if it matches the last character in the range, we just update it.
+  if (aChar == pair.second) {
+    pair.second = pair.second - 1;
+    return;
+  }
+
+  // Our character is in the middle of the range, splitting it in two.
+  // We update the matched range to reflect the values before the character,
+  // and insert a new range that represents the values after.
+  char16_t lastElement = pair.second;
+  pair.second = aChar - 1;
+  aBlocklist.InsertElementAt(pos + 1,
+                             std::make_pair(char16_t(aChar + 1), lastElement));
+}
+
+void InitializeBlocklist(nsTArray<BlocklistRange>& aBlocklist) {
+  aBlocklist.Clear();
+  for (auto const& arr : sBlocklistPairs) {
+    // The hardcoded pairs are already sorted.
+    aBlocklist.AppendElement(std::make_pair(arr[0], arr[1]));
+  }
+
+  nsAutoString extraAllowed;
+  nsresult rv =
+      Preferences::GetString("network.IDN.extra_allowed_chars", extraAllowed);
+  if (NS_SUCCEEDED(rv) && !extraAllowed.IsEmpty()) {
+    const char16_t* cur = extraAllowed.BeginReading();
+    const char16_t* end = extraAllowed.EndReading();
+    // Characters in the allowed list are removed from the blocklist.
+    for (; cur < end; ++cur) {
+      RemoveCharFromBlocklist(*cur, aBlocklist);
+    }
+  }
+
+  nsAutoString extraBlocked;
+  rv = Preferences::GetString("network.IDN.extra_blocked_chars", extraBlocked);
+  // We add each extra blocked character to the blocklist as a separate range.
+  if (NS_SUCCEEDED(rv) && !extraBlocked.IsEmpty()) {
+    for (size_t i = 0; i < extraBlocked.Length(); ++i) {
+      aBlocklist.AppendElement(
+          std::make_pair(extraBlocked[i], extraBlocked[i]));
+    }
+    aBlocklist.Sort(BlocklistEntryComparator());
+  }
+}
+
+}  // namespace net
+}  // namespace mozilla