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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 character set converter.
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "base/logging.h"
#include "third_party/icu/source/common/unicode/ucnv.h"
#include "third_party/icu/source/common/unicode/ucnv_cb.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 {
// 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() = default;
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);
}
} // namespace url