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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.
- #include "url/url_canon.h"
- #include "url/url_canon_internal.h"
- // Query canonicalization in IE
- // ----------------------------
- // IE is very permissive for query parameters specified in links on the page
- // (in contrast to links that it constructs itself based on form data). It does
- // not unescape any character. It does not reject any escape sequence (be they
- // invalid like "%2y" or freaky like %00).
- //
- // IE only escapes spaces and nothing else. Embedded NULLs, tabs (0x09),
- // LF (0x0a), and CR (0x0d) are removed (this probably happens at an earlier
- // layer since they are removed from all portions of the URL). All other
- // characters are passed unmodified. Invalid UTF-16 sequences are preserved as
- // well, with each character in the input being converted to UTF-8. It is the
- // server's job to make sense of this invalid query.
- //
- // Invalid multibyte sequences (for example, invalid UTF-8 on a UTF-8 page)
- // are converted to the invalid character and sent as unescaped UTF-8 (0xef,
- // 0xbf, 0xbd). This may not be canonicalization, the parser may generate these
- // strings before the URL handler ever sees them.
- //
- // Our query canonicalization
- // --------------------------
- // We escape all non-ASCII characters and control characters, like Firefox.
- // This is more conformant to the URL spec, and there do not seem to be many
- // problems relating to Firefox's behavior.
- //
- // Like IE, we will never unescape (although the application may want to try
- // unescaping to present the user with a more understandable URL). We will
- // replace all invalid sequences (including invalid UTF-16 sequences, which IE
- // doesn't) with the "invalid character," and we will escape it.
- namespace url {
- namespace {
- // Returns true if the characters starting at |begin| and going until |end|
- // (non-inclusive) are all representable in 7-bits.
- template<typename CHAR, typename UCHAR>
- bool IsAllASCII(const CHAR* spec, const Component& query) {
- int end = query.end();
- for (int i = query.begin; i < end; i++) {
- if (static_cast<UCHAR>(spec[i]) >= 0x80)
- return false;
- }
- return true;
- }
- // Appends the given string to the output, escaping characters that do not
- // match the given |type| in SharedCharTypes. This version will accept 8 or 16
- // bit characters, but assumes that they have only 7-bit values. It also assumes
- // that all UTF-8 values are correct, so doesn't bother checking
- template<typename CHAR>
- void AppendRaw8BitQueryString(const CHAR* source, int length,
- CanonOutput* output) {
- for (int i = 0; i < length; i++) {
- if (!IsQueryChar(static_cast<unsigned char>(source[i])))
- AppendEscapedChar(static_cast<unsigned char>(source[i]), output);
- else // Doesn't need escaping.
- output->push_back(static_cast<char>(source[i]));
- }
- }
- // Runs the converter on the given UTF-8 input. Since the converter expects
- // UTF-16, we have to convert first. The converter must be non-NULL.
- void RunConverter(const char* spec,
- const Component& query,
- CharsetConverter* converter,
- CanonOutput* output) {
- DCHECK(query.is_valid());
- // This function will replace any misencoded values with the invalid
- // character. This is what we want so we don't have to check for error.
- RawCanonOutputW<1024> utf16;
- ConvertUTF8ToUTF16(&spec[query.begin], static_cast<size_t>(query.len),
- &utf16);
- converter->ConvertFromUTF16(utf16.data(), utf16.length(), output);
- }
- // Runs the converter with the given UTF-16 input. We don't have to do
- // anything, but this overridden function allows us to use the same code
- // for both UTF-8 and UTF-16 input.
- void RunConverter(const char16_t* spec,
- const Component& query,
- CharsetConverter* converter,
- CanonOutput* output) {
- DCHECK(query.is_valid());
- converter->ConvertFromUTF16(&spec[query.begin],
- static_cast<size_t>(query.len), output);
- }
- template<typename CHAR, typename UCHAR>
- void DoConvertToQueryEncoding(const CHAR* spec,
- const Component& query,
- CharsetConverter* converter,
- CanonOutput* output) {
- if (IsAllASCII<CHAR, UCHAR>(spec, query)) {
- // Easy: the input can just appended with no character set conversions.
- AppendRaw8BitQueryString(&spec[query.begin], query.len, output);
- } else {
- // Harder: convert to the proper encoding first.
- if (converter) {
- // Run the converter to get an 8-bit string, then append it, escaping
- // necessary values.
- RawCanonOutput<1024> eight_bit;
- RunConverter(spec, query, converter, &eight_bit);
- AppendRaw8BitQueryString(eight_bit.data(), eight_bit.length(), output);
- } else {
- // No converter, do our own UTF-8 conversion.
- AppendStringOfType(&spec[query.begin], static_cast<size_t>(query.len),
- CHAR_QUERY, output);
- }
- }
- }
- template<typename CHAR, typename UCHAR>
- void DoCanonicalizeQuery(const CHAR* spec,
- const Component& query,
- CharsetConverter* converter,
- CanonOutput* output,
- Component* out_query) {
- if (query.len < 0) {
- *out_query = Component();
- return;
- }
- output->push_back('?');
- out_query->begin = output->length();
- DoConvertToQueryEncoding<CHAR, UCHAR>(spec, query, converter, output);
- out_query->len = output->length() - out_query->begin;
- }
- } // namespace
- void CanonicalizeQuery(const char* spec,
- const Component& query,
- CharsetConverter* converter,
- CanonOutput* output,
- Component* out_query) {
- DoCanonicalizeQuery<char, unsigned char>(spec, query, converter,
- output, out_query);
- }
- void CanonicalizeQuery(const char16_t* spec,
- const Component& query,
- CharsetConverter* converter,
- CanonOutput* output,
- Component* out_query) {
- DoCanonicalizeQuery<char16_t, char16_t>(spec, query, converter, output,
- out_query);
- }
- void ConvertUTF16ToQueryEncoding(const char16_t* input,
- const Component& query,
- CharsetConverter* converter,
- CanonOutput* output) {
- DoConvertToQueryEncoding<char16_t, char16_t>(input, query, converter, output);
- }
- } // namespace url
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