blob: 601736ee93cc809ac31f416400758e6e6ed8cd2e [file] [log] [blame]
// 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 "base/lazy_instance.h"
#include "base/logging.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 {
namespace {
// A wrapper to use LazyInstance<>::Leaky with ICU's 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 (
// ).
// See http:// and references therein
// for more details.
struct UIDNAWrapper {
UIDNAWrapper() {
UErrorCode err = U_ZERO_ERROR;
// TODO(jungshik): Change options as different parties (browsers,
// registrars, search engines) converge toward a consensus.
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";
value = NULL;
UIDNA* value;
} // namespace
static base::LazyInstance<UIDNAWrapper>::Leaky g_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 base::char16* src, int src_len, CanonOutputW* output) {
DCHECK(output->length() == 0); // Output buffer is assumed empty.
UIDNA* uidna = g_uidna.Get().value;
DCHECK(uidna != NULL);
while (true) {
UErrorCode err = U_ZERO_ERROR;
int output_length = uidna_nameToASCII(uidna, src, src_len, output->data(),
output->capacity(), &info, &err);
if (U_SUCCESS(err) && info.errors == 0) {
return true;
// TODO(jungshik): Look at info.errors to handle them case-by-case basis
// if necessary.
if (err != U_BUFFER_OVERFLOW_ERROR || info.errors != 0)
return false; // Unknown error, give up.
// Not enough room in our buffer, expand.
} // namespace url