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diff --git a/intl/components/src/IDNA.h b/intl/components/src/IDNA.h
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+++ b/intl/components/src/IDNA.h
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+/* 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/. */
+#ifndef intl_components_IDNA_h_
+#define intl_components_IDNA_h_
+
+#include "mozilla/intl/ICU4CGlue.h"
+
+#include "unicode/uidna.h"
+
+namespace mozilla::intl {
+
+/**
+ * This component is a Mozilla-focused API for the Internationalizing Domain
+ * Names in Applications (IDNA).
+ *
+ * See UTS #46 for details.
+ * http://unicode.org/reports/tr46/
+ */
+class IDNA final {
+ public:
+  ~IDNA();
+
+  /**
+   * UTS #46 specifies two specific types of processing: Transitional Processing
+   * and NonTransitional Processing.
+   *
+   * See http://unicode.org/reports/tr46/#Compatibility_Processing
+   */
+  enum class ProcessingType {
+    Transitional,
+    NonTransitional,
+  };
+
+  /**
+   * Create an IDNA object, with specifying the type of processing by enum
+   * ProcessingType.
+   *
+   * Currently the implementation enables CheckBidi flag and CheckJoiners by
+   * default.
+   *
+   * See UTS #46, '4 Processing' for details.
+   * http://unicode.org/reports/tr46/#Processing
+   */
+  static Result<UniquePtr<IDNA>, ICUError> TryCreate(
+      ProcessingType aProcessing);
+
+  /**
+   * This class contains the error code information of IDNA processing.
+   */
+  class Info final {
+   public:
+    /**
+     * Check if there's any error.
+     */
+    bool HasErrors() const { return mErrorCode != 0; }
+
+    /**
+     * If the domain name label starts with "xn--", then the label contains
+     * Punycode. This checks if the domain name label has invalid Punycode.
+     *
+     * See https://www.rfc-editor.org/rfc/rfc3492.html
+     */
+    bool HasInvalidPunycode() const {
+      return (mErrorCode & UIDNA_ERROR_PUNYCODE) != 0;
+    }
+
+    /* The label was successfully ACE (Punycode) decoded but the resulting
+     * string had severe validation errors. For example,
+     * it might contain characters that are not allowed in ACE labels,
+     * or it might not be normalized.
+     */
+    bool HasInvalidAceLabel() const {
+      return (mErrorCode & UIDNA_ERROR_INVALID_ACE_LABEL) != 0;
+    }
+
+    /**
+     * Checks if the domain name label has any invalid hyphen characters.
+     *
+     * See CheckHyphens flag for details in UTS #46[1].
+     * - The label must not contain a U+002D HYPHEN-MINUS character in both the
+     *   third and fourth positions.
+     * - The label must neither begin nor end with a U+002D HYPHEN-MINUS
+     *   character.
+     *
+     * [1]: http://unicode.org/reports/tr46/#Validity_Criteria
+     */
+    bool HasInvalidHyphen() const {
+      uint32_t hyphenErrors = UIDNA_ERROR_LEADING_HYPHEN |
+                              UIDNA_ERROR_TRAILING_HYPHEN |
+                              UIDNA_ERROR_HYPHEN_3_4;
+      return (mErrorCode & hyphenErrors) != 0;
+    }
+
+   private:
+    friend class IDNA;
+    explicit Info(const UIDNAInfo* aUinfo) : mErrorCode(aUinfo->errors) {}
+
+    uint32_t mErrorCode = 0;
+  };
+
+  /**
+   * Converts a domain name label to its Unicode form for human-readable
+   * display, and writes the Unicode form into buffer, and returns IDNA::Info
+   * object.
+   * The IDNA::Info object contains the detail information about the processing
+   * result of IDNA call, caller should check the result by calling
+   * IDNA::Info::HasErrors() as well.
+   */
+  template <typename Buffer>
+  Result<Info, ICUError> LabelToUnicode(Span<const char16_t> aLabel,
+                                        Buffer& aBuffer) {
+    UIDNAInfo uinfo = UIDNA_INFO_INITIALIZER;
+    MOZ_TRY(FillBufferWithICUCall(
+        aBuffer, [&](UChar* target, int32_t length, UErrorCode* status) {
+          return uidna_labelToUnicode(mIDNA.GetConst(), aLabel.data(),
+                                      aLabel.size(), target, length, &uinfo,
+                                      status);
+        }));
+
+    return Info{&uinfo};
+  }
+
+ private:
+  explicit IDNA(UIDNA* aIDNA) : mIDNA(aIDNA) {}
+
+  ICUPointer<UIDNA> mIDNA = ICUPointer<UIDNA>(nullptr);
+};
+}  // namespace mozilla::intl
+#endif  // intl_components_IDNA_h_