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- // Copyright 2013 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- // ICU-based IDNA converter.
- #include <stdint.h>
- #include <stdlib.h>
- #include <string.h>
- #include <ostream>
- #include "base/check_op.h"
- #include "third_party/icu/source/common/unicode/uidna.h"
- #include "third_party/icu/source/common/unicode/utypes.h"
- #include "url/url_canon_icu.h"
- #include "url/url_canon_internal.h" // for _itoa_s
- namespace url {
- // Use UIDNA, a C pointer to a UTS46/IDNA 2008 handling object opened with
- // uidna_openUTS46().
- //
- // We use UTS46 with BiDiCheck to migrate from IDNA 2003 (with unassigned
- // code points allowed) to IDNA 2008 with
- // the backward compatibility in mind. What it does:
- //
- // 1. Use the up-to-date Unicode data.
- // 2. Define a case folding/mapping with the up-to-date Unicode data as
- // in IDNA 2003.
- // 3. Use transitional mechanism for 4 deviation characters (sharp-s,
- // final sigma, ZWJ and ZWNJ) for now.
- // 4. Continue to allow symbols and punctuations.
- // 5. Apply new BiDi check rules more permissive than the IDNA 2003 BiDI rules.
- // 6. Do not apply STD3 rules
- // 7. Do not allow unassigned code points.
- //
- // It also closely matches what IE 10 does except for the BiDi check (
- // http://goo.gl/3XBhqw ).
- // See http://http://unicode.org/reports/tr46/ and references therein
- // for more details.
- UIDNA* GetUIDNA() {
- static UIDNA* uidna = [] {
- UErrorCode err = U_ZERO_ERROR;
- // TODO(jungshik): Change options as different parties (browsers,
- // registrars, search engines) converge toward a consensus.
- UIDNA* value = uidna_openUTS46(UIDNA_CHECK_BIDI, &err);
- if (U_FAILURE(err)) {
- CHECK(false) << "failed to open UTS46 data with error: "
- << u_errorName(err)
- << ". If you see this error message in a test environment "
- << "your test environment likely lacks the required data "
- << "tables for libicu. See https://crbug.com/778929.";
- value = nullptr;
- }
- return value;
- }();
- return uidna;
- }
- // Converts the Unicode input representing a hostname to ASCII using IDN rules.
- // The output must be ASCII, but is represented as wide characters.
- //
- // On success, the output will be filled with the ASCII host name and it will
- // return true. Unlike most other canonicalization functions, this assumes that
- // the output is empty. The beginning of the host will be at offset 0, and
- // the length of the output will be set to the length of the new host name.
- //
- // On error, this will return false. The output in this case is undefined.
- // TODO(jungshik): use UTF-8/ASCII version of nameToASCII.
- // Change the function signature and callers accordingly to avoid unnecessary
- // conversions in our code. In addition, consider using icu::IDNA's UTF-8/ASCII
- // version with StringByteSink. That way, we can avoid C wrappers and additional
- // string conversion.
- bool IDNToASCII(const char16_t* src, int src_len, CanonOutputW* output) {
- DCHECK(output->length() == 0); // Output buffer is assumed empty.
- UIDNA* uidna = GetUIDNA();
- DCHECK(uidna != nullptr);
- while (true) {
- UErrorCode err = U_ZERO_ERROR;
- UIDNAInfo info = UIDNA_INFO_INITIALIZER;
- int output_length = uidna_nameToASCII(uidna, src, src_len, output->data(),
- output->capacity(), &info, &err);
- // Ignore various errors for web compatibility. The options are specified
- // by the WHATWG URL Standard. See
- // - https://unicode.org/reports/tr46/
- // - https://url.spec.whatwg.org/#concept-domain-to-ascii
- // (we set beStrict to false)
- // Disable the "CheckHyphens" option in UTS #46. See
- // - https://crbug.com/804688
- // - https://github.com/whatwg/url/issues/267
- info.errors &= ~UIDNA_ERROR_HYPHEN_3_4;
- info.errors &= ~UIDNA_ERROR_LEADING_HYPHEN;
- info.errors &= ~UIDNA_ERROR_TRAILING_HYPHEN;
- // Disable the "VerifyDnsLength" option in UTS #46.
- info.errors &= ~UIDNA_ERROR_EMPTY_LABEL;
- info.errors &= ~UIDNA_ERROR_LABEL_TOO_LONG;
- info.errors &= ~UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
- if (U_SUCCESS(err) && info.errors == 0) {
- // Per WHATWG URL, it is a failure if the ToASCII output is empty.
- //
- // ICU would usually return UIDNA_ERROR_EMPTY_LABEL in this case, but we
- // want to continue allowing http://abc..def/ while forbidding http:///.
- //
- if (output_length == 0) {
- return false;
- }
- output->set_length(output_length);
- return true;
- }
- if (err != U_BUFFER_OVERFLOW_ERROR || info.errors != 0)
- return false; // Unknown error, give up.
- // Not enough room in our buffer, expand.
- output->Resize(output_length);
- }
- }
- } // namespace url
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