blob: 95e9c1384e1e074bf9b11a8f8cbd55995712c0f7 [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 integration functions.
#include <stdlib.h>
#include <string.h>
#include "base/logging.h"
#include "third_party/icu/public/common/unicode/ucnv.h"
#include "third_party/icu/public/common/unicode/ucnv_cb.h"
#include "third_party/icu/public/common/unicode/uidna.h"
#include "url/url_canon_icu.h"
#include "url/url_canon_internal.h" // for _itoa_s
namespace url_canon {
namespace {
// Called when converting a character that can not be represented, this will
// append an escaped version of the numerical character reference for that code
// point. It is of the form "&#1234;" and we will escape the non-digits to
// "%26%231234%3B". Why? This is what Netscape did back in the olden days.
void appendURLEscapedChar(const void* context,
UConverterFromUnicodeArgs* from_args,
const UChar* code_units,
int32_t length,
UChar32 code_point,
UConverterCallbackReason reason,
UErrorCode* err) {
if (reason == UCNV_UNASSIGNED) {
*err = U_ZERO_ERROR;
const static int prefix_len = 6;
const static char prefix[prefix_len + 1] = "%26%23"; // "&#" percent-escaped
ucnv_cbFromUWriteBytes(from_args, prefix, prefix_len, 0, err);
DCHECK(code_point < 0x110000);
char number[8]; // Max Unicode code point is 7 digits.
_itoa_s(code_point, number, 10);
int number_len = static_cast<int>(strlen(number));
ucnv_cbFromUWriteBytes(from_args, number, number_len, 0, err);
const static int postfix_len = 3;
const static char postfix[postfix_len + 1] = "%3B"; // ";" percent-escaped
ucnv_cbFromUWriteBytes(from_args, postfix, postfix_len, 0, err);
}
}
// A class for scoping the installation of the invalid character callback.
class AppendHandlerInstaller {
public:
// The owner of this object must ensure that the converter is alive for the
// duration of this object's lifetime.
AppendHandlerInstaller(UConverter* converter) : converter_(converter) {
UErrorCode err = U_ZERO_ERROR;
ucnv_setFromUCallBack(converter_, appendURLEscapedChar, 0,
&old_callback_, &old_context_, &err);
}
~AppendHandlerInstaller() {
UErrorCode err = U_ZERO_ERROR;
ucnv_setFromUCallBack(converter_, old_callback_, old_context_, 0, 0, &err);
}
private:
UConverter* converter_;
UConverterFromUCallback old_callback_;
const void* old_context_;
};
} // namespace
ICUCharsetConverter::ICUCharsetConverter(UConverter* converter)
: converter_(converter) {
}
ICUCharsetConverter::~ICUCharsetConverter() {
}
void ICUCharsetConverter::ConvertFromUTF16(const base::char16* input,
int input_len,
CanonOutput* output) {
// Install our error handler. It will be called for character that can not
// be represented in the destination character set.
AppendHandlerInstaller handler(converter_);
int begin_offset = output->length();
int dest_capacity = output->capacity() - begin_offset;
output->set_length(output->length());
do {
UErrorCode err = U_ZERO_ERROR;
char* dest = &output->data()[begin_offset];
int required_capacity = ucnv_fromUChars(converter_, dest, dest_capacity,
input, input_len, &err);
if (err != U_BUFFER_OVERFLOW_ERROR) {
output->set_length(begin_offset + required_capacity);
return;
}
// Output didn't fit, expand
dest_capacity = required_capacity;
output->Resize(begin_offset + dest_capacity);
} while (true);
}
// 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.
bool IDNToASCII(const base::char16* src, int src_len, CanonOutputW* output) {
DCHECK(output->length() == 0); // Output buffer is assumed empty.
while (true) {
// Use ALLOW_UNASSIGNED to be more tolerant of hostnames that violate
// the spec (which do exist). This does not present any risk and is a
// little more future proof.
UErrorCode err = U_ZERO_ERROR;
int num_converted = uidna_IDNToASCII(src, src_len, output->data(),
output->capacity(),
UIDNA_ALLOW_UNASSIGNED, NULL, &err);
if (err == U_ZERO_ERROR) {
output->set_length(num_converted);
return true;
}
if (err != U_BUFFER_OVERFLOW_ERROR)
return false; // Unknown error, give up.
// Not enough room in our buffer, expand.
output->Resize(output->capacity() * 2);
}
}
bool ReadUTFChar(const char* str, int* begin, int length,
unsigned* code_point_out) {
int code_point; // Avoids warning when U8_NEXT writes -1 to it.
U8_NEXT(str, *begin, length, code_point);
*code_point_out = static_cast<unsigned>(code_point);
// The ICU macro above moves to the next char, we want to point to the last
// char consumed.
(*begin)--;
// Validate the decoded value.
if (U_IS_UNICODE_CHAR(code_point))
return true;
*code_point_out = kUnicodeReplacementCharacter;
return false;
}
bool ReadUTFChar(const base::char16* str, int* begin, int length,
unsigned* code_point) {
if (U16_IS_SURROGATE(str[*begin])) {
if (!U16_IS_SURROGATE_LEAD(str[*begin]) || *begin + 1 >= length ||
!U16_IS_TRAIL(str[*begin + 1])) {
// Invalid surrogate pair.
*code_point = kUnicodeReplacementCharacter;
return false;
} else {
// Valid surrogate pair.
*code_point = U16_GET_SUPPLEMENTARY(str[*begin], str[*begin + 1]);
(*begin)++;
}
} else {
// Not a surrogate, just one 16-bit word.
*code_point = str[*begin];
}
if (U_IS_UNICODE_CHAR(*code_point))
return true;
// Invalid code point.
*code_point = kUnicodeReplacementCharacter;
return false;
}
} // namespace url_canon