url/url_util.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "url/url_util.h"
   6
   7 #include <string.h>
   8 #include <vector>
   9
  10 #include "base/debug/leak_annotations.h"
  11 #include "base/logging.h"
  12 #include "url/url_canon_internal.h"
  13 #include "url/url_file.h"
  14 #include "url/url_util_internal.h"
  15
  16 namespace url {
  17
  18 namespace {
  19
  20 // ASCII-specific tolower.  The standard library's tolower is locale sensitive,
  21 // so we don't want to use it here.
  22 template<class Char>
  23 inline Char ToLowerASCII(Char c) {
  24   return (c >= 'A' && c <= 'Z') ? (c + ('a' - 'A')) : c;
  25 }
  26
  27 // Backend for LowerCaseEqualsASCII.
  28 template<typename Iter>
  29 inline bool DoLowerCaseEqualsASCII(Iter a_begin, Iter a_end, const char* b) {
  30   for (Iter it = a_begin; it != a_end; ++it, ++b) {
  31     if (!*b || ToLowerASCII(*it) != *b)
  32       return false;
  33   }
  34   return *b == 0;
  35 }
  36
  37 const int kNumStandardURLSchemes = 8;
  38 const char* kStandardURLSchemes[kNumStandardURLSchemes] = {
  39   kHttpScheme,
  40   kHttpsScheme,
  41   kFileScheme,  // Yes, file urls can have a hostname!
  42   kFtpScheme,
  43   kGopherScheme,
  44   kWsScheme,    // WebSocket.
  45   kWssScheme,   // WebSocket secure.
  46   kFileSystemScheme,
  47 };
  48
  49 // List of the currently installed standard schemes. This list is lazily
  50 // initialized by InitStandardSchemes and is leaked on shutdown to prevent
  51 // any destructors from being called that will slow us down or cause problems.
  52 std::vector<const char*>* standard_schemes = NULL;
  53
  54 // See the LockStandardSchemes declaration in the header.
  55 bool standard_schemes_locked = false;
  56
  57 // Ensures that the standard_schemes list is initialized, does nothing if it
  58 // already has values.
  59 void InitStandardSchemes() {
  60   if (standard_schemes)
  61     return;
  62   standard_schemes = new std::vector<const char*>;
  63   for (int i = 0; i < kNumStandardURLSchemes; i++)
  64     standard_schemes->push_back(kStandardURLSchemes[i]);
  65 }
  66
  67 // Given a string and a range inside the string, compares it to the given
  68 // lower-case |compare_to| buffer.
  69 template<typename CHAR>
  70 inline bool DoCompareSchemeComponent(const CHAR* spec,
  71                                      const Component& component,
  72                                      const char* compare_to) {
  73   if (!component.is_nonempty())
  74     return compare_to[0] == 0;  // When component is empty, match empty scheme.
  75   return LowerCaseEqualsASCII(&spec[component.begin],
  76                               &spec[component.end()],
  77                               compare_to);
  78 }
  79
  80 // Returns true if the given scheme identified by |scheme| within |spec| is one
  81 // of the registered "standard" schemes.
  82 template<typename CHAR>
  83 bool DoIsStandard(const CHAR* spec, const Component& scheme) {
  84   if (!scheme.is_nonempty())
  85     return false;  // Empty or invalid schemes are non-standard.
  86
  87   InitStandardSchemes();
  88   for (size_t i = 0; i < standard_schemes->size(); i++) {
  89     if (LowerCaseEqualsASCII(&spec[scheme.begin], &spec[scheme.end()],
  90                              standard_schemes->at(i)))
  91       return true;
  92   }
  93   return false;
  94 }
  95
  96 template<typename CHAR>
  97 bool DoFindAndCompareScheme(const CHAR* str,
  98                             int str_len,
  99                             const char* compare,
 100                             Component* found_scheme) {
 101   // Before extracting scheme, canonicalize the URL to remove any whitespace.
 102   // This matches the canonicalization done in DoCanonicalize function.
 103   RawCanonOutputT<CHAR> whitespace_buffer;
 104   int spec_len;
 105   const CHAR* spec = RemoveURLWhitespace(str, str_len,
 106                                          &whitespace_buffer, &spec_len);
 107
 108   Component our_scheme;
 109   if (!ExtractScheme(spec, spec_len, &our_scheme)) {
 110     // No scheme.
 111     if (found_scheme)
 112       *found_scheme = Component();
 113     return false;
 114   }
 115   if (found_scheme)
 116     *found_scheme = our_scheme;
 117   return DoCompareSchemeComponent(spec, our_scheme, compare);
 118 }
 119
 120 template<typename CHAR>
 121 bool DoCanonicalize(const CHAR* in_spec,
 122                     int in_spec_len,
 123                     bool trim_path_end,
 124                     CharsetConverter* charset_converter,
 125                     CanonOutput* output,
 126                     Parsed* output_parsed) {
 127   // Remove any whitespace from the middle of the relative URL, possibly
 128   // copying to the new buffer.
 129   RawCanonOutputT<CHAR> whitespace_buffer;
 130   int spec_len;
 131   const CHAR* spec = RemoveURLWhitespace(in_spec, in_spec_len,
 132                                          &whitespace_buffer, &spec_len);
 133
 134   Parsed parsed_input;
 135 #ifdef WIN32
 136   // For Windows, we allow things that look like absolute Windows paths to be
 137   // fixed up magically to file URLs. This is done for IE compatability. For
 138   // example, this will change "c:/foo" into a file URL rather than treating
 139   // it as a URL with the protocol "c". It also works for UNC ("\\foo\bar.txt").
 140   // There is similar logic in url_canon_relative.cc for
 141   //
 142   // For Max & Unix, we don't do this (the equivalent would be "/foo/bar" which
 143   // has no meaning as an absolute path name. This is because browsers on Mac
 144   // & Unix don't generally do this, so there is no compatibility reason for
 145   // doing so.
 146   if (DoesBeginUNCPath(spec, 0, spec_len, false) ||
 147       DoesBeginWindowsDriveSpec(spec, 0, spec_len)) {
 148     ParseFileURL(spec, spec_len, &parsed_input);
 149     return CanonicalizeFileURL(spec, spec_len, parsed_input, charset_converter,
 150                                output, output_parsed);
 151   }
 152 #endif
 153
 154   Component scheme;
 155   if (!ExtractScheme(spec, spec_len, &scheme))
 156     return false;
 157
 158   // This is the parsed version of the input URL, we have to canonicalize it
 159   // before storing it in our object.
 160   bool success;
 161   if (DoCompareSchemeComponent(spec, scheme, url::kFileScheme)) {
 162     // File URLs are special.
 163     ParseFileURL(spec, spec_len, &parsed_input);
 164     success = CanonicalizeFileURL(spec, spec_len, parsed_input,
 165                                   charset_converter, output, output_parsed);
 166   } else if (DoCompareSchemeComponent(spec, scheme, url::kFileSystemScheme)) {
 167     // Filesystem URLs are special.
 168     ParseFileSystemURL(spec, spec_len, &parsed_input);
 169     success = CanonicalizeFileSystemURL(spec, spec_len, parsed_input,
 170                                         charset_converter, output,
 171                                         output_parsed);
 172
 173   } else if (DoIsStandard(spec, scheme)) {
 174     // All "normal" URLs.
 175     ParseStandardURL(spec, spec_len, &parsed_input);
 176     success = CanonicalizeStandardURL(spec, spec_len, parsed_input,
 177                                       charset_converter, output, output_parsed);
 178
 179   } else if (DoCompareSchemeComponent(spec, scheme, url::kMailToScheme)) {
 180     // Mailto are treated like a standard url with only a scheme, path, query
 181     ParseMailtoURL(spec, spec_len, &parsed_input);
 182     success = CanonicalizeMailtoURL(spec, spec_len, parsed_input, output,
 183                                     output_parsed);
 184
 185   } else {
 186     // "Weird" URLs like data: and javascript:
 187     ParsePathURL(spec, spec_len, trim_path_end, &parsed_input);
 188     success = CanonicalizePathURL(spec, spec_len, parsed_input, output,
 189                                   output_parsed);
 190   }
 191   return success;
 192 }
 193
 194 template<typename CHAR>
 195 bool DoResolveRelative(const char* base_spec,
 196                        int base_spec_len,
 197                        const Parsed& base_parsed,
 198                        const CHAR* in_relative,
 199                        int in_relative_length,
 200                        CharsetConverter* charset_converter,
 201                        CanonOutput* output,
 202                        Parsed* output_parsed) {
 203   // Remove any whitespace from the middle of the relative URL, possibly
 204   // copying to the new buffer.
 205   RawCanonOutputT<CHAR> whitespace_buffer;
 206   int relative_length;
 207   const CHAR* relative = RemoveURLWhitespace(in_relative, in_relative_length,
 208                                              &whitespace_buffer,
 209                                              &relative_length);
 210   bool base_is_authority_based = false;
 211   bool base_is_hierarchical = false;
 212   if (base_spec &&
 213       base_parsed.scheme.is_nonempty()) {
 214     int after_scheme = base_parsed.scheme.end() + 1;  // Skip past the colon.
 215     int num_slashes = CountConsecutiveSlashes(base_spec, after_scheme,
 216                                               base_spec_len);
 217     base_is_authority_based = num_slashes > 1;
 218     base_is_hierarchical = num_slashes > 0;
 219   }
 220
 221   bool standard_base_scheme =
 222       base_parsed.scheme.is_nonempty() &&
 223       DoIsStandard(base_spec, base_parsed.scheme);
 224
 225   bool is_relative;
 226   Component relative_component;
 227   if (!IsRelativeURL(base_spec, base_parsed, relative, relative_length,
 228                      (base_is_hierarchical || standard_base_scheme),
 229                      &is_relative, &relative_component)) {
 230     // Error resolving.
 231     return false;
 232   }
 233
 234   // Pretend for a moment that |base_spec| is a standard URL. Normally
 235   // non-standard URLs are treated as PathURLs, but if the base has an
 236   // authority we would like to preserve it.
 237   if (is_relative && base_is_authority_based && !standard_base_scheme) {
 238     Parsed base_parsed_authority;
 239     ParseStandardURL(base_spec, base_spec_len, &base_parsed_authority);
 240     if (base_parsed_authority.host.is_nonempty()) {
 241       bool did_resolve_succeed =
 242           ResolveRelativeURL(base_spec, base_parsed_authority, false, relative,
 243                              relative_component, charset_converter, output,
 244                              output_parsed);
 245       // The output_parsed is incorrect at this point (because it was built
 246       // based on base_parsed_authority instead of base_parsed) and needs to be
 247       // re-created.
 248       ParsePathURL(output->data(), output->length(), true,
 249                    output_parsed);
 250       return did_resolve_succeed;
 251     }
 252   } else if (is_relative) {
 253     // Relative, resolve and canonicalize.
 254     bool file_base_scheme = base_parsed.scheme.is_nonempty() &&
 255         DoCompareSchemeComponent(base_spec, base_parsed.scheme, kFileScheme);
 256     return ResolveRelativeURL(base_spec, base_parsed, file_base_scheme, relative,
 257                               relative_component, charset_converter, output,
 258                               output_parsed);
 259   }
 260
 261   // Not relative, canonicalize the input.
 262   return DoCanonicalize(relative, relative_length, true, charset_converter,
 263                         output, output_parsed);
 264 }
 265
 266 template<typename CHAR>
 267 bool DoReplaceComponents(const char* spec,
 268                          int spec_len,
 269                          const Parsed& parsed,
 270                          const Replacements<CHAR>& replacements,
 271                          CharsetConverter* charset_converter,
 272                          CanonOutput* output,
 273                          Parsed* out_parsed) {
 274   // If the scheme is overridden, just do a simple string substitution and
 275   // reparse the whole thing. There are lots of edge cases that we really don't
 276   // want to deal with. Like what happens if I replace "http://e:8080/foo"
 277   // with a file. Does it become "file:///E:/8080/foo" where the port number
 278   // becomes part of the path? Parsing that string as a file URL says "yes"
 279   // but almost no sane rule for dealing with the components individually would
 280   // come up with that.
 281   //
 282   // Why allow these crazy cases at all? Programatically, there is almost no
 283   // case for replacing the scheme. The most common case for hitting this is
 284   // in JS when building up a URL using the location object. In this case, the
 285   // JS code expects the string substitution behavior:
 286   //   http://www.w3.org/TR/2008/WD-html5-20080610/structured.html#common3
 287   if (replacements.IsSchemeOverridden()) {
 288     // Canonicalize the new scheme so it is 8-bit and can be concatenated with
 289     // the existing spec.
 290     RawCanonOutput<128> scheme_replaced;
 291     Component scheme_replaced_parsed;
 292     CanonicalizeScheme(replacements.sources().scheme,
 293                        replacements.components().scheme,
 294                        &scheme_replaced, &scheme_replaced_parsed);
 295
 296     // We can assume that the input is canonicalized, which means it always has
 297     // a colon after the scheme (or where the scheme would be).
 298     int spec_after_colon = parsed.scheme.is_valid() ? parsed.scheme.end() + 1
 299                                                     : 1;
 300     if (spec_len - spec_after_colon > 0) {
 301       scheme_replaced.Append(&spec[spec_after_colon],
 302                              spec_len - spec_after_colon);
 303     }
 304
 305     // We now need to completely re-parse the resulting string since its meaning
 306     // may have changed with the different scheme.
 307     RawCanonOutput<128> recanonicalized;
 308     Parsed recanonicalized_parsed;
 309     DoCanonicalize(scheme_replaced.data(), scheme_replaced.length(), true,
 310                    charset_converter,
 311                    &recanonicalized, &recanonicalized_parsed);
 312
 313     // Recurse using the version with the scheme already replaced. This will now
 314     // use the replacement rules for the new scheme.
 315     //
 316     // Warning: this code assumes that ReplaceComponents will re-check all
 317     // components for validity. This is because we can't fail if DoCanonicalize
 318     // failed above since theoretically the thing making it fail could be
 319     // getting replaced here. If ReplaceComponents didn't re-check everything,
 320     // we wouldn't know if something *not* getting replaced is a problem.
 321     // If the scheme-specific replacers are made more intelligent so they don't
 322     // re-check everything, we should instead recanonicalize the whole thing
 323     // after this call to check validity (this assumes replacing the scheme is
 324     // much much less common than other types of replacements, like clearing the
 325     // ref).
 326     Replacements<CHAR> replacements_no_scheme = replacements;
 327     replacements_no_scheme.SetScheme(NULL, Component());
 328     return DoReplaceComponents(recanonicalized.data(), recanonicalized.length(),
 329                                recanonicalized_parsed, replacements_no_scheme,
 330                                charset_converter, output, out_parsed);
 331   }
 332
 333   // If we get here, then we know the scheme doesn't need to be replaced, so can
 334   // just key off the scheme in the spec to know how to do the replacements.
 335   if (DoCompareSchemeComponent(spec, parsed.scheme, url::kFileScheme)) {
 336     return ReplaceFileURL(spec, parsed, replacements, charset_converter, output,
 337                           out_parsed);
 338   }
 339   if (DoCompareSchemeComponent(spec, parsed.scheme, url::kFileSystemScheme)) {
 340     return ReplaceFileSystemURL(spec, parsed, replacements, charset_converter,
 341                                 output, out_parsed);
 342   }
 343   if (DoIsStandard(spec, parsed.scheme)) {
 344     return ReplaceStandardURL(spec, parsed, replacements, charset_converter,
 345                               output, out_parsed);
 346   }
 347   if (DoCompareSchemeComponent(spec, parsed.scheme, url::kMailToScheme)) {
 348     return ReplaceMailtoURL(spec, parsed, replacements, output, out_parsed);
 349   }
 350
 351   // Default is a path URL.
 352   return ReplacePathURL(spec, parsed, replacements, output, out_parsed);
 353 }
 354
 355 }  // namespace
 356
 357 void Initialize() {
 358   InitStandardSchemes();
 359 }
 360
 361 void Shutdown() {
 362   if (standard_schemes) {
 363     delete standard_schemes;
 364     standard_schemes = NULL;
 365   }
 366 }
 367
 368 void AddStandardScheme(const char* new_scheme) {
 369   // If this assert triggers, it means you've called AddStandardScheme after
 370   // LockStandardSchemes have been called (see the header file for
 371   // LockStandardSchemes for more).
 372   //
 373   // This normally means you're trying to set up a new standard scheme too late
 374   // in your application's init process. Locate where your app does this
 375   // initialization and calls LockStandardScheme, and add your new standard
 376   // scheme there.
 377   DCHECK(!standard_schemes_locked) <<
 378       "Trying to add a standard scheme after the list has been locked.";
 379
 380   size_t scheme_len = strlen(new_scheme);
 381   if (scheme_len == 0)
 382     return;
 383
 384   // Dulicate the scheme into a new buffer and add it to the list of standard
 385   // schemes. This pointer will be leaked on shutdown.
 386   char* dup_scheme = new char[scheme_len + 1];
 387   ANNOTATE_LEAKING_OBJECT_PTR(dup_scheme);
 388   memcpy(dup_scheme, new_scheme, scheme_len + 1);
 389
 390   InitStandardSchemes();
 391   standard_schemes->push_back(dup_scheme);
 392 }
 393
 394 void LockStandardSchemes() {
 395   standard_schemes_locked = true;
 396 }
 397
 398 bool IsStandard(const char* spec, const Component& scheme) {
 399   return DoIsStandard(spec, scheme);
 400 }
 401
 402 bool IsStandard(const base::char16* spec, const Component& scheme) {
 403   return DoIsStandard(spec, scheme);
 404 }
 405
 406 bool FindAndCompareScheme(const char* str,
 407                           int str_len,
 408                           const char* compare,
 409                           Component* found_scheme) {
 410   return DoFindAndCompareScheme(str, str_len, compare, found_scheme);
 411 }
 412
 413 bool FindAndCompareScheme(const base::char16* str,
 414                           int str_len,
 415                           const char* compare,
 416                           Component* found_scheme) {
 417   return DoFindAndCompareScheme(str, str_len, compare, found_scheme);
 418 }
 419
 420 bool Canonicalize(const char* spec,
 421                   int spec_len,
 422                   bool trim_path_end,
 423                   CharsetConverter* charset_converter,
 424                   CanonOutput* output,
 425                   Parsed* output_parsed) {
 426   return DoCanonicalize(spec, spec_len, trim_path_end, charset_converter,
 427                         output, output_parsed);
 428 }
 429
 430 bool Canonicalize(const base::char16* spec,
 431                   int spec_len,
 432                   bool trim_path_end,
 433                   CharsetConverter* charset_converter,
 434                   CanonOutput* output,
 435                   Parsed* output_parsed) {
 436   return DoCanonicalize(spec, spec_len, trim_path_end, charset_converter,
 437                         output, output_parsed);
 438 }
 439
 440 bool ResolveRelative(const char* base_spec,
 441                      int base_spec_len,
 442                      const Parsed& base_parsed,
 443                      const char* relative,
 444                      int relative_length,
 445                      CharsetConverter* charset_converter,
 446                      CanonOutput* output,
 447                      Parsed* output_parsed) {
 448   return DoResolveRelative(base_spec, base_spec_len, base_parsed,
 449                            relative, relative_length,
 450                            charset_converter, output, output_parsed);
 451 }
 452
 453 bool ResolveRelative(const char* base_spec,
 454                      int base_spec_len,
 455                      const Parsed& base_parsed,
 456                      const base::char16* relative,
 457                      int relative_length,
 458                      CharsetConverter* charset_converter,
 459                      CanonOutput* output,
 460                      Parsed* output_parsed) {
 461   return DoResolveRelative(base_spec, base_spec_len, base_parsed,
 462                            relative, relative_length,
 463                            charset_converter, output, output_parsed);
 464 }
 465
 466 bool ReplaceComponents(const char* spec,
 467                        int spec_len,
 468                        const Parsed& parsed,
 469                        const Replacements<char>& replacements,
 470                        CharsetConverter* charset_converter,
 471                        CanonOutput* output,
 472                        Parsed* out_parsed) {
 473   return DoReplaceComponents(spec, spec_len, parsed, replacements,
 474                              charset_converter, output, out_parsed);
 475 }
 476
 477 bool ReplaceComponents(const char* spec,
 478                        int spec_len,
 479                        const Parsed& parsed,
 480                        const Replacements<base::char16>& replacements,
 481                        CharsetConverter* charset_converter,
 482                        CanonOutput* output,
 483                        Parsed* out_parsed) {
 484   return DoReplaceComponents(spec, spec_len, parsed, replacements,
 485                              charset_converter, output, out_parsed);
 486 }
 487
 488 // Front-ends for LowerCaseEqualsASCII.
 489 bool LowerCaseEqualsASCII(const char* a_begin,
 490                           const char* a_end,
 491                           const char* b) {
 492   return DoLowerCaseEqualsASCII(a_begin, a_end, b);
 493 }
 494
 495 bool LowerCaseEqualsASCII(const char* a_begin,
 496                           const char* a_end,
 497                           const char* b_begin,
 498                           const char* b_end) {
 499   while (a_begin != a_end && b_begin != b_end &&
 500          ToLowerASCII(*a_begin) == *b_begin) {
 501     a_begin++;
 502     b_begin++;
 503   }
 504   return a_begin == a_end && b_begin == b_end;
 505 }
 506
 507 bool LowerCaseEqualsASCII(const base::char16* a_begin,
 508                           const base::char16* a_end,
 509                           const char* b) {
 510   return DoLowerCaseEqualsASCII(a_begin, a_end, b);
 511 }
 512
 513 void DecodeURLEscapeSequences(const char* input,
 514                               int length,
 515                               CanonOutputW* output) {
 516   RawCanonOutputT<char> unescaped_chars;
 517   for (int i = 0; i < length; i++) {
 518     if (input[i] == '%') {
 519       unsigned char ch;
 520       if (DecodeEscaped(input, &i, length, &ch)) {
 521         unescaped_chars.push_back(ch);
 522       } else {
 523         // Invalid escape sequence, copy the percent literal.
 524         unescaped_chars.push_back('%');
 525       }
 526     } else {
 527       // Regular non-escaped 8-bit character.
 528       unescaped_chars.push_back(input[i]);
 529     }
 530   }
 531
 532   // Convert that 8-bit to UTF-16. It's not clear IE does this at all to
 533   // JavaScript URLs, but Firefox and Safari do.
 534   for (int i = 0; i < unescaped_chars.length(); i++) {
 535     unsigned char uch = static_cast<unsigned char>(unescaped_chars.at(i));
 536     if (uch < 0x80) {
 537       // Non-UTF-8, just append directly
 538       output->push_back(uch);
 539     } else {
 540       // next_ch will point to the last character of the decoded
 541       // character.
 542       int next_character = i;
 543       unsigned code_point;
 544       if (ReadUTFChar(unescaped_chars.data(), &next_character,
 545                       unescaped_chars.length(), &code_point)) {
 546         // Valid UTF-8 character, convert to UTF-16.
 547         AppendUTF16Value(code_point, output);
 548         i = next_character;
 549       } else {
 550         // If there are any sequences that are not valid UTF-8, we keep
 551         // invalid code points and promote to UTF-16. We copy all characters
 552         // from the current position to the end of the identified sequence.
 553         while (i < next_character) {
 554           output->push_back(static_cast<unsigned char>(unescaped_chars.at(i)));
 555           i++;
 556         }
 557         output->push_back(static_cast<unsigned char>(unescaped_chars.at(i)));
 558       }
 559     }
 560   }
 561 }
 562
 563 void EncodeURIComponent(const char* input, int length, CanonOutput* output) {
 564   for (int i = 0; i < length; ++i) {
 565     unsigned char c = static_cast<unsigned char>(input[i]);
 566     if (IsComponentChar(c))
 567       output->push_back(c);
 568     else
 569       AppendEscapedChar(c, output);
 570   }
 571 }
 572
 573 bool CompareSchemeComponent(const char* spec,
 574                             const Component& component,
 575                             const char* compare_to) {
 576   return DoCompareSchemeComponent(spec, component, compare_to);
 577 }
 578
 579 bool CompareSchemeComponent(const base::char16* spec,
 580                             const Component& component,
 581                             const char* compare_to) {
 582   return DoCompareSchemeComponent(spec, component, compare_to);
 583 }
 584
 585 }  // namespace url