Move googleurl into the Chrome repo.

url/url_util.cc

+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <string.h>
+#include <vector>
+
+#include "googleurl/src/url_util.h"
+
+#include "base/logging.h"
+#include "googleurl/src/url_canon_internal.h"
+#include "googleurl/src/url_file.h"
+#include "googleurl/src/url_util_internal.h"
+
+namespace url_util {
+
+const char kFileScheme[] = "file";
+const char kFileSystemScheme[] = "filesystem";
+const char kMailtoScheme[] = "mailto";
+
+namespace {
+
+// ASCII-specific tolower.  The standard library's tolower is locale sensitive,
+// so we don't want to use it here.
+template <class Char> inline Char ToLowerASCII(Char c) {
+  return (c >= 'A' && c <= 'Z') ? (c + ('a' - 'A')) : c;
+}
+
+// Backend for LowerCaseEqualsASCII.
+template<typename Iter>
+inline bool DoLowerCaseEqualsASCII(Iter a_begin, Iter a_end, const char* b) {
+  for (Iter it = a_begin; it != a_end; ++it, ++b) {
+    if (!*b || ToLowerASCII(*it) != *b)
+      return false;
+  }
+  return *b == 0;
+}
+
+const int kNumStandardURLSchemes = 8;
+const char* kStandardURLSchemes[kNumStandardURLSchemes] = {
+  "http",
+  "https",
+  kFileScheme,  // Yes, file urls can have a hostname!
+  "ftp",
+  "gopher",
+  "ws",  // WebSocket.
+  "wss",  // WebSocket secure.
+  kFileSystemScheme,
+};
+
+// List of the currently installed standard schemes. This list is lazily
+// initialized by InitStandardSchemes and is leaked on shutdown to prevent
+// any destructors from being called that will slow us down or cause problems.
+std::vector<const char*>* standard_schemes = NULL;
+
+// See the LockStandardSchemes declaration in the header.
+bool standard_schemes_locked = false;
+
+// Ensures that the standard_schemes list is initialized, does nothing if it
+// already has values.
+void InitStandardSchemes() {
+  if (standard_schemes)
+    return;
+  standard_schemes = new std::vector<const char*>;
+  for (int i = 0; i < kNumStandardURLSchemes; i++)
+    standard_schemes->push_back(kStandardURLSchemes[i]);
+}
+
+// Given a string and a range inside the string, compares it to the given
+// lower-case |compare_to| buffer.
+template<typename CHAR>
+inline bool DoCompareSchemeComponent(const CHAR* spec,
+                                     const url_parse::Component& component,
+                                     const char* compare_to) {
+  if (!component.is_nonempty())
+    return compare_to[0] == 0;  // When component is empty, match empty scheme.
+  return LowerCaseEqualsASCII(&spec[component.begin],
+                              &spec[component.end()],
+                              compare_to);
+}
+
+// Returns true if the given scheme identified by |scheme| within |spec| is one
+// of the registered "standard" schemes.
+template<typename CHAR>
+bool DoIsStandard(const CHAR* spec, const url_parse::Component& scheme) {
+  if (!scheme.is_nonempty())
+    return false;  // Empty or invalid schemes are non-standard.
+
+  InitStandardSchemes();
+  for (size_t i = 0; i < standard_schemes->size(); i++) {
+    if (LowerCaseEqualsASCII(&spec[scheme.begin], &spec[scheme.end()],
+                             standard_schemes->at(i)))
+      return true;
+  }
+  return false;
+}
+
+template<typename CHAR>
+bool DoFindAndCompareScheme(const CHAR* str,
+                            int str_len,
+                            const char* compare,
+                            url_parse::Component* found_scheme) {
+  // Before extracting scheme, canonicalize the URL to remove any whitespace.
+  // This matches the canonicalization done in DoCanonicalize function.
+  url_canon::RawCanonOutputT<CHAR> whitespace_buffer;
+  int spec_len;
+  const CHAR* spec = RemoveURLWhitespace(str, str_len,
+                                         &whitespace_buffer, &spec_len);
+
+  url_parse::Component our_scheme;
+  if (!url_parse::ExtractScheme(spec, spec_len, &our_scheme)) {
+    // No scheme.
+    if (found_scheme)
+      *found_scheme = url_parse::Component();
+    return false;
+  }
+  if (found_scheme)
+    *found_scheme = our_scheme;
+  return DoCompareSchemeComponent(spec, our_scheme, compare);
+}
+
+template<typename CHAR>
+bool DoCanonicalize(const CHAR* in_spec, int in_spec_len,
+                    url_canon::CharsetConverter* charset_converter,
+                    url_canon::CanonOutput* output,
+                    url_parse::Parsed* output_parsed) {
+  // Remove any whitespace from the middle of the relative URL, possibly
+  // copying to the new buffer.
+  url_canon::RawCanonOutputT<CHAR> whitespace_buffer;
+  int spec_len;
+  const CHAR* spec = RemoveURLWhitespace(in_spec, in_spec_len,
+                                         &whitespace_buffer, &spec_len);
+
+  url_parse::Parsed parsed_input;
+#ifdef WIN32
+  // For Windows, we allow things that look like absolute Windows paths to be
+  // fixed up magically to file URLs. This is done for IE compatability. For
+  // example, this will change "c:/foo" into a file URL rather than treating
+  // it as a URL with the protocol "c". It also works for UNC ("\\foo\bar.txt").
+  // There is similar logic in url_canon_relative.cc for
+  //
+  // For Max & Unix, we don't do this (the equivalent would be "/foo/bar" which
+  // has no meaning as an absolute path name. This is because browsers on Mac
+  // & Unix don't generally do this, so there is no compatibility reason for
+  // doing so.
+  if (url_parse::DoesBeginUNCPath(spec, 0, spec_len, false) ||
+      url_parse::DoesBeginWindowsDriveSpec(spec, 0, spec_len)) {
+    url_parse::ParseFileURL(spec, spec_len, &parsed_input);
+    return url_canon::CanonicalizeFileURL(spec, spec_len, parsed_input,
+                                          charset_converter,
+                                          output, output_parsed);
+  }
+#endif
+
+  url_parse::Component scheme;
+  if (!url_parse::ExtractScheme(spec, spec_len, &scheme))
+    return false;
+
+  // This is the parsed version of the input URL, we have to canonicalize it
+  // before storing it in our object.
+  bool success;
+  if (DoCompareSchemeComponent(spec, scheme, kFileScheme)) {
+    // File URLs are special.
+    url_parse::ParseFileURL(spec, spec_len, &parsed_input);
+    success = url_canon::CanonicalizeFileURL(spec, spec_len, parsed_input,
+                                             charset_converter, output,
+                                             output_parsed);
+  } else if (DoCompareSchemeComponent(spec, scheme, kFileSystemScheme)) {
+    // Filesystem URLs are special.
+    url_parse::ParseFileSystemURL(spec, spec_len, &parsed_input);
+    success = url_canon::CanonicalizeFileSystemURL(spec, spec_len,
+                                                   parsed_input,
+                                                   charset_converter,
+                                                   output, output_parsed);
+
+  } else if (DoIsStandard(spec, scheme)) {
+    // All "normal" URLs.
+    url_parse::ParseStandardURL(spec, spec_len, &parsed_input);
+    success = url_canon::CanonicalizeStandardURL(spec, spec_len, parsed_input,
+                                                 charset_converter,
+                                                 output, output_parsed);
+
+  } else if (DoCompareSchemeComponent(spec, scheme, kMailtoScheme)) {
+    // Mailto are treated like a standard url with only a scheme, path, query
+    url_parse::ParseMailtoURL(spec, spec_len, &parsed_input);
+    success = url_canon::CanonicalizeMailtoURL(spec, spec_len, parsed_input,
+                                               output, output_parsed);
+
+  } else {
+    // "Weird" URLs like data: and javascript:
+    url_parse::ParsePathURL(spec, spec_len, &parsed_input);
+    success = url_canon::CanonicalizePathURL(spec, spec_len, parsed_input,
+                                             output, output_parsed);
+  }
+  return success;
+}
+
+template<typename CHAR>
+bool DoResolveRelative(const char* base_spec,
+                       int base_spec_len,
+                       const url_parse::Parsed& base_parsed,
+                       const CHAR* in_relative,
+                       int in_relative_length,
+                       url_canon::CharsetConverter* charset_converter,
+                       url_canon::CanonOutput* output,
+                       url_parse::Parsed* output_parsed) {
+  // Remove any whitespace from the middle of the relative URL, possibly
+  // copying to the new buffer.
+  url_canon::RawCanonOutputT<CHAR> whitespace_buffer;
+  int relative_length;
+  const CHAR* relative = RemoveURLWhitespace(in_relative, in_relative_length,
+                                             &whitespace_buffer,
+                                             &relative_length);
+  bool base_is_authority_based = false;
+  bool base_is_hierarchical = false;
+  if (base_spec &&
+      base_parsed.scheme.is_nonempty()) {
+    int after_scheme = base_parsed.scheme.end() + 1;  // Skip past the colon.
+    int num_slashes = url_parse::CountConsecutiveSlashes(
+        base_spec, after_scheme, base_spec_len);
+    base_is_authority_based = num_slashes > 1;
+    base_is_hierarchical = num_slashes > 0;
+  }
+
+  bool standard_base_scheme =
+      base_parsed.scheme.is_nonempty() &&
+      DoIsStandard(base_spec, base_parsed.scheme);
+
+  bool is_relative;
+  url_parse::Component relative_component;
+  if (!url_canon::IsRelativeURL(base_spec, base_parsed,
+                                relative, relative_length,
+                                (base_is_hierarchical || standard_base_scheme),
+                                &is_relative,
+                                &relative_component)) {
+    // Error resolving.
+    return false;
+  }
+
+  // Pretend for a moment that |base_spec| is a standard URL. Normally
+  // non-standard URLs are treated as PathURLs, but if the base has an
+  // authority we would like to preserve it.
+  if (is_relative && base_is_authority_based && !standard_base_scheme) {
+    url_parse::Parsed base_parsed_authority;
+    ParseStandardURL(base_spec, base_spec_len, &base_parsed_authority);
+    if (base_parsed_authority.host.is_nonempty()) {
+      bool did_resolve_succeed =
+          url_canon::ResolveRelativeURL(base_spec, base_parsed_authority,
+                                        false, relative,
+                                        relative_component, charset_converter,
+                                        output, output_parsed);
+      // The output_parsed is incorrect at this point (because it was built
+      // based on base_parsed_authority instead of base_parsed) and needs to be
+      // re-created.
+      ParsePathURL(output->data(), output->length(), output_parsed);
+      return did_resolve_succeed;
+    }
+  } else if (is_relative) {
+    // Relative, resolve and canonicalize.
+    bool file_base_scheme = base_parsed.scheme.is_nonempty() &&
+        DoCompareSchemeComponent(base_spec, base_parsed.scheme, kFileScheme);
+    return url_canon::ResolveRelativeURL(base_spec, base_parsed,
+                                         file_base_scheme, relative,
+                                         relative_component, charset_converter,
+                                         output, output_parsed);
+  }
+
+  // Not relative, canonicalize the input.
+  return DoCanonicalize(relative, relative_length, charset_converter,
+                        output, output_parsed);
+}
+
+template<typename CHAR>
+bool DoReplaceComponents(const char* spec,
+                         int spec_len,
+                         const url_parse::Parsed& parsed,
+                         const url_canon::Replacements<CHAR>& replacements,
+                         url_canon::CharsetConverter* charset_converter,
+                         url_canon::CanonOutput* output,
+                         url_parse::Parsed* out_parsed) {
+  // If the scheme is overridden, just do a simple string substitution and
+  // reparse the whole thing. There are lots of edge cases that we really don't
+  // want to deal with. Like what happens if I replace "http://e:8080/foo"
+  // with a file. Does it become "file:///E:/8080/foo" where the port number
+  // becomes part of the path? Parsing that string as a file URL says "yes"
+  // but almost no sane rule for dealing with the components individually would
+  // come up with that.
+  //
+  // Why allow these crazy cases at all? Programatically, there is almost no
+  // case for replacing the scheme. The most common case for hitting this is
+  // in JS when building up a URL using the location object. In this case, the
+  // JS code expects the string substitution behavior:
+  //   http://www.w3.org/TR/2008/WD-html5-20080610/structured.html#common3
+  if (replacements.IsSchemeOverridden()) {
+    // Canonicalize the new scheme so it is 8-bit and can be concatenated with
+    // the existing spec.
+    url_canon::RawCanonOutput<128> scheme_replaced;
+    url_parse::Component scheme_replaced_parsed;
+    url_canon::CanonicalizeScheme(
+        replacements.sources().scheme,
+        replacements.components().scheme,
+        &scheme_replaced, &scheme_replaced_parsed);
+
+    // We can assume that the input is canonicalized, which means it always has
+    // a colon after the scheme (or where the scheme would be).
+    int spec_after_colon = parsed.scheme.is_valid() ? parsed.scheme.end() + 1
+                                                    : 1;
+    if (spec_len - spec_after_colon > 0) {
+      scheme_replaced.Append(&spec[spec_after_colon],
+                             spec_len - spec_after_colon);
+    }
+
+    // We now need to completely re-parse the resulting string since its meaning
+    // may have changed with the different scheme.
+    url_canon::RawCanonOutput<128> recanonicalized;
+    url_parse::Parsed recanonicalized_parsed;
+    DoCanonicalize(scheme_replaced.data(), scheme_replaced.length(),
+                   charset_converter,
+                   &recanonicalized, &recanonicalized_parsed);
+
+    // Recurse using the version with the scheme already replaced. This will now
+    // use the replacement rules for the new scheme.
+    //
+    // Warning: this code assumes that ReplaceComponents will re-check all
+    // components for validity. This is because we can't fail if DoCanonicalize
+    // failed above since theoretically the thing making it fail could be
+    // getting replaced here. If ReplaceComponents didn't re-check everything,
+    // we wouldn't know if something *not* getting replaced is a problem.
+    // If the scheme-specific replacers are made more intelligent so they don't
+    // re-check everything, we should instead recanonicalize the whole thing
+    // after this call to check validity (this assumes replacing the scheme is
+    // much much less common than other types of replacements, like clearing the
+    // ref).
+    url_canon::Replacements<CHAR> replacements_no_scheme = replacements;
+    replacements_no_scheme.SetScheme(NULL, url_parse::Component());
+    return DoReplaceComponents(recanonicalized.data(), recanonicalized.length(),
+                               recanonicalized_parsed, replacements_no_scheme,
+                               charset_converter, output, out_parsed);
+  }
+
+  // If we get here, then we know the scheme doesn't need to be replaced, so can
+  // just key off the scheme in the spec to know how to do the replacements.
+  if (DoCompareSchemeComponent(spec, parsed.scheme, kFileScheme)) {
+    return url_canon::ReplaceFileURL(spec, parsed, replacements,
+                                     charset_converter, output, out_parsed);
+  }
+  if (DoCompareSchemeComponent(spec, parsed.scheme, kFileSystemScheme)) {
+    return url_canon::ReplaceFileSystemURL(spec, parsed, replacements,
+                                           charset_converter, output,
+                                           out_parsed);
+  }
+  if (DoIsStandard(spec, parsed.scheme)) {
+    return url_canon::ReplaceStandardURL(spec, parsed, replacements,
+                                         charset_converter, output, out_parsed);
+  }
+  if (DoCompareSchemeComponent(spec, parsed.scheme, kMailtoScheme)) {
+     return url_canon::ReplaceMailtoURL(spec, parsed, replacements,
+                                        output, out_parsed);
+  }
+
+  // Default is a path URL.
+  return url_canon::ReplacePathURL(spec, parsed, replacements,
+                                   output, out_parsed);
+}
+
+}  // namespace
+
+void Initialize() {
+  InitStandardSchemes();
+}
+
+void Shutdown() {
+  if (standard_schemes) {
+    delete standard_schemes;
+    standard_schemes = NULL;
+  }
+}
+
+void AddStandardScheme(const char* new_scheme) {
+  // If this assert triggers, it means you've called AddStandardScheme after
+  // LockStandardSchemes have been called (see the header file for
+  // LockStandardSchemes for more).
+  //
+  // This normally means you're trying to set up a new standard scheme too late
+  // in your application's init process. Locate where your app does this
+  // initialization and calls LockStandardScheme, and add your new standard
+  // scheme there.
+  DCHECK(!standard_schemes_locked) <<
+      "Trying to add a standard scheme after the list has been locked.";
+
+  size_t scheme_len = strlen(new_scheme);
+  if (scheme_len == 0)
+    return;
+
+  // Dulicate the scheme into a new buffer and add it to the list of standard
+  // schemes. This pointer will be leaked on shutdown.
+  char* dup_scheme = new char[scheme_len + 1];
+  memcpy(dup_scheme, new_scheme, scheme_len + 1);
+
+  InitStandardSchemes();
+  standard_schemes->push_back(dup_scheme);
+}
+
+void LockStandardSchemes() {
+  standard_schemes_locked = true;
+}
+
+bool IsStandard(const char* spec, const url_parse::Component& scheme) {
+  return DoIsStandard(spec, scheme);
+}
+
+bool IsStandard(const char16* spec, const url_parse::Component& scheme) {
+  return DoIsStandard(spec, scheme);
+}
+
+bool FindAndCompareScheme(const char* str,
+                          int str_len,
+                          const char* compare,
+                          url_parse::Component* found_scheme) {
+  return DoFindAndCompareScheme(str, str_len, compare, found_scheme);
+}
+
+bool FindAndCompareScheme(const char16* str,
+                          int str_len,
+                          const char* compare,
+                          url_parse::Component* found_scheme) {
+  return DoFindAndCompareScheme(str, str_len, compare, found_scheme);
+}
+
+bool Canonicalize(const char* spec,
+                  int spec_len,
+                  url_canon::CharsetConverter* charset_converter,
+                  url_canon::CanonOutput* output,
+                  url_parse::Parsed* output_parsed) {
+  return DoCanonicalize(spec, spec_len, charset_converter,
+                        output, output_parsed);
+}
+
+bool Canonicalize(const char16* spec,
+                  int spec_len,
+                  url_canon::CharsetConverter* charset_converter,
+                  url_canon::CanonOutput* output,
+                  url_parse::Parsed* output_parsed) {
+  return DoCanonicalize(spec, spec_len, charset_converter,
+                        output, output_parsed);
+}
+
+bool ResolveRelative(const char* base_spec,
+                     int base_spec_len,
+                     const url_parse::Parsed& base_parsed,
+                     const char* relative,
+                     int relative_length,
+                     url_canon::CharsetConverter* charset_converter,
+                     url_canon::CanonOutput* output,
+                     url_parse::Parsed* output_parsed) {
+  return DoResolveRelative(base_spec, base_spec_len, base_parsed,
+                           relative, relative_length,
+                           charset_converter, output, output_parsed);
+}
+
+bool ResolveRelative(const char* base_spec,
+                     int base_spec_len,
+                     const url_parse::Parsed& base_parsed,
+                     const char16* relative,
+                     int relative_length,
+                     url_canon::CharsetConverter* charset_converter,
+                     url_canon::CanonOutput* output,
+                     url_parse::Parsed* output_parsed) {
+  return DoResolveRelative(base_spec, base_spec_len, base_parsed,
+                           relative, relative_length,
+                           charset_converter, output, output_parsed);
+}
+
+bool ReplaceComponents(const char* spec,
+                       int spec_len,
+                       const url_parse::Parsed& parsed,
+                       const url_canon::Replacements<char>& replacements,
+                       url_canon::CharsetConverter* charset_converter,
+                       url_canon::CanonOutput* output,
+                       url_parse::Parsed* out_parsed) {
+  return DoReplaceComponents(spec, spec_len, parsed, replacements,
+                             charset_converter, output, out_parsed);
+}
+
+bool ReplaceComponents(const char* spec,
+                       int spec_len,
+                       const url_parse::Parsed& parsed,
+                       const url_canon::Replacements<char16>& replacements,
+                       url_canon::CharsetConverter* charset_converter,
+                       url_canon::CanonOutput* output,
+                       url_parse::Parsed* out_parsed) {
+  return DoReplaceComponents(spec, spec_len, parsed, replacements,
+                             charset_converter, output, out_parsed);
+}
+
+// Front-ends for LowerCaseEqualsASCII.
+bool LowerCaseEqualsASCII(const char* a_begin,
+                          const char* a_end,
+                          const char* b) {
+  return DoLowerCaseEqualsASCII(a_begin, a_end, b);
+}
+
+bool LowerCaseEqualsASCII(const char* a_begin,
+                          const char* a_end,
+                          const char* b_begin,
+                          const char* b_end) {
+  while (a_begin != a_end && b_begin != b_end &&
+         ToLowerASCII(*a_begin) == *b_begin) {
+    a_begin++;
+    b_begin++;
+  }
+  return a_begin == a_end && b_begin == b_end;
+}
+
+bool LowerCaseEqualsASCII(const char16* a_begin,
+                          const char16* a_end,
+                          const char* b) {
+  return DoLowerCaseEqualsASCII(a_begin, a_end, b);
+}
+
+void DecodeURLEscapeSequences(const char* input, int length,
+                              url_canon::CanonOutputW* output) {
+  url_canon::RawCanonOutputT<char> unescaped_chars;
+  for (int i = 0; i < length; i++) {
+    if (input[i] == '%') {
+      unsigned char ch;
+      if (url_canon::DecodeEscaped(input, &i, length, &ch)) {
+        unescaped_chars.push_back(ch);
+      } else {
+        // Invalid escape sequence, copy the percent literal.
+        unescaped_chars.push_back('%');
+      }
+    } else {
+      // Regular non-escaped 8-bit character.
+      unescaped_chars.push_back(input[i]);
+    }
+  }
+
+  // Convert that 8-bit to UTF-16. It's not clear IE does this at all to
+  // JavaScript URLs, but Firefox and Safari do.
+  for (int i = 0; i < unescaped_chars.length(); i++) {
+    unsigned char uch = static_cast<unsigned char>(unescaped_chars.at(i));
+    if (uch < 0x80) {
+      // Non-UTF-8, just append directly
+      output->push_back(uch);
+    } else {
+      // next_ch will point to the last character of the decoded
+      // character.
+      int next_character = i;
+      unsigned code_point;
+      if (url_canon::ReadUTFChar(unescaped_chars.data(), &next_character,
+                                 unescaped_chars.length(), &code_point)) {
+        // Valid UTF-8 character, convert to UTF-16.
+        url_canon::AppendUTF16Value(code_point, output);
+        i = next_character;
+      } else {
+        // If there are any sequences that are not valid UTF-8, we keep
+        // invalid code points and promote to UTF-16. We copy all characters
+        // from the current position to the end of the identified sequence.
+        while (i < next_character) {
+          output->push_back(static_cast<unsigned char>(unescaped_chars.at(i)));
+          i++;
+        }
+        output->push_back(static_cast<unsigned char>(unescaped_chars.at(i)));
+      }
+    }
+  }
+}
+
+void EncodeURIComponent(const char* input, int length,
+                        url_canon::CanonOutput* output) {
+  for (int i = 0; i < length; ++i) {
+    unsigned char c = static_cast<unsigned char>(input[i]);
+    if (url_canon::IsComponentChar(c))
+      output->push_back(c);
+    else
+      AppendEscapedChar(c, output);
+  }
+}
+
+bool CompareSchemeComponent(const char* spec,
+                            const url_parse::Component& component,
+                            const char* compare_to) {
+  return DoCompareSchemeComponent(spec, component, compare_to);
+}
+
+bool CompareSchemeComponent(const char16* spec,
+                            const url_parse::Component& component,
+                            const char* compare_to) {
+  return DoCompareSchemeComponent(spec, component, compare_to);
+}
+
+}  // namespace url_util