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#ifndef URL_URL_CANON_H_
6#define URL_URL_CANON_H_
7
8#include <stdlib.h>
9#include <string.h>
10
11#include "base/strings/string16.h"
12#include "url/url_export.h"
13#include "url/url_parse.h"
14
15namespace url {
16
17// Canonicalizer output -------------------------------------------------------
18
19// Base class for the canonicalizer output, this maintains a buffer and
20// supports simple resizing and append operations on it.
21//
22// It is VERY IMPORTANT that no virtual function calls be made on the common
23// code path. We only have two virtual function calls, the destructor and a
24// resize function that is called when the existing buffer is not big enough.
25// The derived class is then in charge of setting up our buffer which we will
26// manage.
27template<typename T>
28class CanonOutputT {
29 public:
30  CanonOutputT() : buffer_(NULL), buffer_len_(0), cur_len_(0) {
31  }
32  virtual ~CanonOutputT() {
33  }
34
35  // Implemented to resize the buffer. This function should update the buffer
36  // pointer to point to the new buffer, and any old data up to |cur_len_| in
37  // the buffer must be copied over.
38  //
39  // The new size |sz| must be larger than buffer_len_.
40  virtual void Resize(int sz) = 0;
41
42  // Accessor for returning a character at a given position. The input offset
43  // must be in the valid range.
44  inline char at(int offset) const {
45    return buffer_[offset];
46  }
47
48  // Sets the character at the given position. The given position MUST be less
49  // than the length().
50  inline void set(int offset, int ch) {
51    buffer_[offset] = ch;
52  }
53
54  // Returns the number of characters currently in the buffer.
55  inline int length() const {
56    return cur_len_;
57  }
58
59  // Returns the current capacity of the buffer. The length() is the number of
60  // characters that have been declared to be written, but the capacity() is
61  // the number that can be written without reallocation. If the caller must
62  // write many characters at once, it can make sure there is enough capacity,
63  // write the data, then use set_size() to declare the new length().
64  int capacity() const {
65    return buffer_len_;
66  }
67
68  // Called by the user of this class to get the output. The output will NOT
69  // be NULL-terminated. Call length() to get the
70  // length.
71  const T* data() const {
72    return buffer_;
73  }
74  T* data() {
75    return buffer_;
76  }
77
78  // Shortens the URL to the new length. Used for "backing up" when processing
79  // relative paths. This can also be used if an external function writes a lot
80  // of data to the buffer (when using the "Raw" version below) beyond the end,
81  // to declare the new length.
82  //
83  // This MUST NOT be used to expand the size of the buffer beyond capacity().
84  void set_length(int new_len) {
85    cur_len_ = new_len;
86  }
87
88  // This is the most performance critical function, since it is called for
89  // every character.
90  void push_back(T ch) {
91    // In VC2005, putting this common case first speeds up execution
92    // dramatically because this branch is predicted as taken.
93    if (cur_len_ < buffer_len_) {
94      buffer_[cur_len_] = ch;
95      cur_len_++;
96      return;
97    }
98
99    // Grow the buffer to hold at least one more item. Hopefully we won't have
100    // to do this very often.
101    if (!Grow(1))
102      return;
103
104    // Actually do the insertion.
105    buffer_[cur_len_] = ch;
106    cur_len_++;
107  }
108
109  // Appends the given string to the output.
110  void Append(const T* str, int str_len) {
111    if (cur_len_ + str_len > buffer_len_) {
112      if (!Grow(cur_len_ + str_len - buffer_len_))
113        return;
114    }
115    for (int i = 0; i < str_len; i++)
116      buffer_[cur_len_ + i] = str[i];
117    cur_len_ += str_len;
118  }
119
120 protected:
121  // Grows the given buffer so that it can fit at least |min_additional|
122  // characters. Returns true if the buffer could be resized, false on OOM.
123  bool Grow(int min_additional) {
124    static const int kMinBufferLen = 16;
125    int new_len = (buffer_len_ == 0) ? kMinBufferLen : buffer_len_;
126    do {
127      if (new_len >= (1 << 30))  // Prevent overflow below.
128        return false;
129      new_len *= 2;
130    } while (new_len < buffer_len_ + min_additional);
131    Resize(new_len);
132    return true;
133  }
134
135  T* buffer_;
136  int buffer_len_;
137
138  // Used characters in the buffer.
139  int cur_len_;
140};
141
142// Simple implementation of the CanonOutput using new[]. This class
143// also supports a static buffer so if it is allocated on the stack, most
144// URLs can be canonicalized with no heap allocations.
145template<typename T, int fixed_capacity = 1024>
146class RawCanonOutputT : public CanonOutputT<T> {
147 public:
148  RawCanonOutputT() : CanonOutputT<T>() {
149    this->buffer_ = fixed_buffer_;
150    this->buffer_len_ = fixed_capacity;
151  }
152  virtual ~RawCanonOutputT() {
153    if (this->buffer_ != fixed_buffer_)
154      delete[] this->buffer_;
155  }
156
157  virtual void Resize(int sz) {
158    T* new_buf = new T[sz];
159    memcpy(new_buf, this->buffer_,
160           sizeof(T) * (this->cur_len_ < sz ? this->cur_len_ : sz));
161    if (this->buffer_ != fixed_buffer_)
162      delete[] this->buffer_;
163    this->buffer_ = new_buf;
164    this->buffer_len_ = sz;
165  }
166
167 protected:
168  T fixed_buffer_[fixed_capacity];
169};
170
171// Normally, all canonicalization output is in narrow characters. We support
172// the templates so it can also be used internally if a wide buffer is
173// required.
174typedef CanonOutputT<char> CanonOutput;
175typedef CanonOutputT<base::char16> CanonOutputW;
176
177template<int fixed_capacity>
178class RawCanonOutput : public RawCanonOutputT<char, fixed_capacity> {};
179template<int fixed_capacity>
180class RawCanonOutputW : public RawCanonOutputT<base::char16, fixed_capacity> {};
181
182// Character set converter ----------------------------------------------------
183//
184// Converts query strings into a custom encoding. The embedder can supply an
185// implementation of this class to interface with their own character set
186// conversion libraries.
187//
188// Embedders will want to see the unit test for the ICU version.
189
190class URL_EXPORT CharsetConverter {
191 public:
192  CharsetConverter() {}
193  virtual ~CharsetConverter() {}
194
195  // Converts the given input string from UTF-16 to whatever output format the
196  // converter supports. This is used only for the query encoding conversion,
197  // which does not fail. Instead, the converter should insert "invalid
198  // character" characters in the output for invalid sequences, and do the
199  // best it can.
200  //
201  // If the input contains a character not representable in the output
202  // character set, the converter should append the HTML entity sequence in
203  // decimal, (such as "&#20320;") with escaping of the ampersand, number
204  // sign, and semicolon (in the previous example it would be
205  // "%26%2320320%3B"). This rule is based on what IE does in this situation.
206  virtual void ConvertFromUTF16(const base::char16* input,
207                                int input_len,
208                                CanonOutput* output) = 0;
209};
210
211// Whitespace -----------------------------------------------------------------
212
213// Searches for whitespace that should be removed from the middle of URLs, and
214// removes it. Removed whitespace are tabs and newlines, but NOT spaces. Spaces
215// are preserved, which is what most browsers do. A pointer to the output will
216// be returned, and the length of that output will be in |output_len|.
217//
218// This should be called before parsing if whitespace removal is desired (which
219// it normally is when you are canonicalizing).
220//
221// If no whitespace is removed, this function will not use the buffer and will
222// return a pointer to the input, to avoid the extra copy. If modification is
223// required, the given |buffer| will be used and the returned pointer will
224// point to the beginning of the buffer.
225//
226// Therefore, callers should not use the buffer, since it may actually be empty,
227// use the computed pointer and |*output_len| instead.
228URL_EXPORT const char* RemoveURLWhitespace(const char* input, int input_len,
229                                           CanonOutputT<char>* buffer,
230                                           int* output_len);
231URL_EXPORT const base::char16* RemoveURLWhitespace(
232    const base::char16* input,
233    int input_len,
234    CanonOutputT<base::char16>* buffer,
235    int* output_len);
236
237// IDN ------------------------------------------------------------------------
238
239// Converts the Unicode input representing a hostname to ASCII using IDN rules.
240// The output must fall in the ASCII range, but will be encoded in UTF-16.
241//
242// On success, the output will be filled with the ASCII host name and it will
243// return true. Unlike most other canonicalization functions, this assumes that
244// the output is empty. The beginning of the host will be at offset 0, and
245// the length of the output will be set to the length of the new host name.
246//
247// On error, returns false. The output in this case is undefined.
248URL_EXPORT bool IDNToASCII(const base::char16* src,
249                           int src_len,
250                           CanonOutputW* output);
251
252// Piece-by-piece canonicalizers ----------------------------------------------
253//
254// These individual canonicalizers append the canonicalized versions of the
255// corresponding URL component to the given std::string. The spec and the
256// previously-identified range of that component are the input. The range of
257// the canonicalized component will be written to the output component.
258//
259// These functions all append to the output so they can be chained. Make sure
260// the output is empty when you start.
261//
262// These functions returns boolean values indicating success. On failure, they
263// will attempt to write something reasonable to the output so that, if
264// displayed to the user, they will recognise it as something that's messed up.
265// Nothing more should ever be done with these invalid URLs, however.
266
267// Scheme: Appends the scheme and colon to the URL. The output component will
268// indicate the range of characters up to but not including the colon.
269//
270// Canonical URLs always have a scheme. If the scheme is not present in the
271// input, this will just write the colon to indicate an empty scheme. Does not
272// append slashes which will be needed before any authority components for most
273// URLs.
274//
275// The 8-bit version requires UTF-8 encoding.
276URL_EXPORT bool CanonicalizeScheme(const char* spec,
277                                   const Component& scheme,
278                                   CanonOutput* output,
279                                   Component* out_scheme);
280URL_EXPORT bool CanonicalizeScheme(const base::char16* spec,
281                                   const Component& scheme,
282                                   CanonOutput* output,
283                                   Component* out_scheme);
284
285// User info: username/password. If present, this will add the delimiters so
286// the output will be "<username>:<password>@" or "<username>@". Empty
287// username/password pairs, or empty passwords, will get converted to
288// nonexistant in the canonical version.
289//
290// The components for the username and password refer to ranges in the
291// respective source strings. Usually, these will be the same string, which
292// is legal as long as the two components don't overlap.
293//
294// The 8-bit version requires UTF-8 encoding.
295URL_EXPORT bool CanonicalizeUserInfo(const char* username_source,
296                                     const Component& username,
297                                     const char* password_source,
298                                     const Component& password,
299                                     CanonOutput* output,
300                                     Component* out_username,
301                                     Component* out_password);
302URL_EXPORT bool CanonicalizeUserInfo(const base::char16* username_source,
303                                     const Component& username,
304                                     const base::char16* password_source,
305                                     const Component& password,
306                                     CanonOutput* output,
307                                     Component* out_username,
308                                     Component* out_password);
309
310// This structure holds detailed state exported from the IP/Host canonicalizers.
311// Additional fields may be added as callers require them.
312struct CanonHostInfo {
313  CanonHostInfo() : family(NEUTRAL), num_ipv4_components(0), out_host() {}
314
315  // Convenience function to test if family is an IP address.
316  bool IsIPAddress() const { return family == IPV4 || family == IPV6; }
317
318  // This field summarizes how the input was classified by the canonicalizer.
319  enum Family {
320    NEUTRAL,   // - Doesn't resemble an IP address.  As far as the IP
321               //   canonicalizer is concerned, it should be treated as a
322               //   hostname.
323    BROKEN,    // - Almost an IP, but was not canonicalized.  This could be an
324               //   IPv4 address where truncation occurred, or something
325               //   containing the special characters :[] which did not parse
326               //   as an IPv6 address.  Never attempt to connect to this
327               //   address, because it might actually succeed!
328    IPV4,      // - Successfully canonicalized as an IPv4 address.
329    IPV6,      // - Successfully canonicalized as an IPv6 address.
330  };
331  Family family;
332
333  // If |family| is IPV4, then this is the number of nonempty dot-separated
334  // components in the input text, from 1 to 4.  If |family| is not IPV4,
335  // this value is undefined.
336  int num_ipv4_components;
337
338  // Location of host within the canonicalized output.
339  // CanonicalizeIPAddress() only sets this field if |family| is IPV4 or IPV6.
340  // CanonicalizeHostVerbose() always sets it.
341  Component out_host;
342
343  // |address| contains the parsed IP Address (if any) in its first
344  // AddressLength() bytes, in network order. If IsIPAddress() is false
345  // AddressLength() will return zero and the content of |address| is undefined.
346  unsigned char address[16];
347
348  // Convenience function to calculate the length of an IP address corresponding
349  // to the current IP version in |family|, if any. For use with |address|.
350  int AddressLength() const {
351    return family == IPV4 ? 4 : (family == IPV6 ? 16 : 0);
352  }
353};
354
355
356// Host.
357//
358// The 8-bit version requires UTF-8 encoding.  Use this version when you only
359// need to know whether canonicalization succeeded.
360URL_EXPORT bool CanonicalizeHost(const char* spec,
361                                 const Component& host,
362                                 CanonOutput* output,
363                                 Component* out_host);
364URL_EXPORT bool CanonicalizeHost(const base::char16* spec,
365                                 const Component& host,
366                                 CanonOutput* output,
367                                 Component* out_host);
368
369// Extended version of CanonicalizeHost, which returns additional information.
370// Use this when you need to know whether the hostname was an IP address.
371// A successful return is indicated by host_info->family != BROKEN.  See the
372// definition of CanonHostInfo above for details.
373URL_EXPORT void CanonicalizeHostVerbose(const char* spec,
374                                        const Component& host,
375                                        CanonOutput* output,
376                                        CanonHostInfo* host_info);
377URL_EXPORT void CanonicalizeHostVerbose(const base::char16* spec,
378                                        const Component& host,
379                                        CanonOutput* output,
380                                        CanonHostInfo* host_info);
381
382// IP addresses.
383//
384// Tries to interpret the given host name as an IPv4 or IPv6 address. If it is
385// an IP address, it will canonicalize it as such, appending it to |output|.
386// Additional status information is returned via the |*host_info| parameter.
387// See the definition of CanonHostInfo above for details.
388//
389// This is called AUTOMATICALLY from the host canonicalizer, which ensures that
390// the input is unescaped and name-prepped, etc. It should not normally be
391// necessary or wise to call this directly.
392URL_EXPORT void CanonicalizeIPAddress(const char* spec,
393                                      const Component& host,
394                                      CanonOutput* output,
395                                      CanonHostInfo* host_info);
396URL_EXPORT void CanonicalizeIPAddress(const base::char16* spec,
397                                      const Component& host,
398                                      CanonOutput* output,
399                                      CanonHostInfo* host_info);
400
401// Port: this function will add the colon for the port if a port is present.
402// The caller can pass PORT_UNSPECIFIED as the
403// default_port_for_scheme argument if there is no default port.
404//
405// The 8-bit version requires UTF-8 encoding.
406URL_EXPORT bool CanonicalizePort(const char* spec,
407                                 const Component& port,
408                                 int default_port_for_scheme,
409                                 CanonOutput* output,
410                                 Component* out_port);
411URL_EXPORT bool CanonicalizePort(const base::char16* spec,
412                                 const Component& port,
413                                 int default_port_for_scheme,
414                                 CanonOutput* output,
415                                 Component* out_port);
416
417// Returns the default port for the given canonical scheme, or PORT_UNSPECIFIED
418// if the scheme is unknown.
419URL_EXPORT int DefaultPortForScheme(const char* scheme, int scheme_len);
420
421// Path. If the input does not begin in a slash (including if the input is
422// empty), we'll prepend a slash to the path to make it canonical.
423//
424// The 8-bit version assumes UTF-8 encoding, but does not verify the validity
425// of the UTF-8 (i.e., you can have invalid UTF-8 sequences, invalid
426// characters, etc.). Normally, URLs will come in as UTF-16, so this isn't
427// an issue. Somebody giving us an 8-bit path is responsible for generating
428// the path that the server expects (we'll escape high-bit characters), so
429// if something is invalid, it's their problem.
430URL_EXPORT bool CanonicalizePath(const char* spec,
431                                 const Component& path,
432                                 CanonOutput* output,
433                                 Component* out_path);
434URL_EXPORT bool CanonicalizePath(const base::char16* spec,
435                                 const Component& path,
436                                 CanonOutput* output,
437                                 Component* out_path);
438
439// Canonicalizes the input as a file path. This is like CanonicalizePath except
440// that it also handles Windows drive specs. For example, the path can begin
441// with "c|\" and it will get properly canonicalized to "C:/".
442// The string will be appended to |*output| and |*out_path| will be updated.
443//
444// The 8-bit version requires UTF-8 encoding.
445URL_EXPORT bool FileCanonicalizePath(const char* spec,
446                                     const Component& path,
447                                     CanonOutput* output,
448                                     Component* out_path);
449URL_EXPORT bool FileCanonicalizePath(const base::char16* spec,
450                                     const Component& path,
451                                     CanonOutput* output,
452                                     Component* out_path);
453
454// Query: Prepends the ? if needed.
455//
456// The 8-bit version requires the input to be UTF-8 encoding. Incorrectly
457// encoded characters (in UTF-8 or UTF-16) will be replaced with the Unicode
458// "invalid character." This function can not fail, we always just try to do
459// our best for crazy input here since web pages can set it themselves.
460//
461// This will convert the given input into the output encoding that the given
462// character set converter object provides. The converter will only be called
463// if necessary, for ASCII input, no conversions are necessary.
464//
465// The converter can be NULL. In this case, the output encoding will be UTF-8.
466URL_EXPORT void CanonicalizeQuery(const char* spec,
467                                  const Component& query,
468                                  CharsetConverter* converter,
469                                  CanonOutput* output,
470                                  Component* out_query);
471URL_EXPORT void CanonicalizeQuery(const base::char16* spec,
472                                  const Component& query,
473                                  CharsetConverter* converter,
474                                  CanonOutput* output,
475                                  Component* out_query);
476
477// Ref: Prepends the # if needed. The output will be UTF-8 (this is the only
478// canonicalizer that does not produce ASCII output). The output is
479// guaranteed to be valid UTF-8.
480//
481// This function will not fail. If the input is invalid UTF-8/UTF-16, we'll use
482// the "Unicode replacement character" for the confusing bits and copy the rest.
483URL_EXPORT void CanonicalizeRef(const char* spec,
484                                const Component& path,
485                                CanonOutput* output,
486                                Component* out_path);
487URL_EXPORT void CanonicalizeRef(const base::char16* spec,
488                                const Component& path,
489                                CanonOutput* output,
490                                Component* out_path);
491
492// Full canonicalizer ---------------------------------------------------------
493//
494// These functions replace any string contents, rather than append as above.
495// See the above piece-by-piece functions for information specific to
496// canonicalizing individual components.
497//
498// The output will be ASCII except the reference fragment, which may be UTF-8.
499//
500// The 8-bit versions require UTF-8 encoding.
501
502// Use for standard URLs with authorities and paths.
503URL_EXPORT bool CanonicalizeStandardURL(const char* spec,
504                                        int spec_len,
505                                        const Parsed& parsed,
506                                        CharsetConverter* query_converter,
507                                        CanonOutput* output,
508                                        Parsed* new_parsed);
509URL_EXPORT bool CanonicalizeStandardURL(const base::char16* spec,
510                                        int spec_len,
511                                        const Parsed& parsed,
512                                        CharsetConverter* query_converter,
513                                        CanonOutput* output,
514                                        Parsed* new_parsed);
515
516// Use for file URLs.
517URL_EXPORT bool CanonicalizeFileURL(const char* spec,
518                                    int spec_len,
519                                    const Parsed& parsed,
520                                    CharsetConverter* query_converter,
521                                    CanonOutput* output,
522                                    Parsed* new_parsed);
523URL_EXPORT bool CanonicalizeFileURL(const base::char16* spec,
524                                    int spec_len,
525                                    const Parsed& parsed,
526                                    CharsetConverter* query_converter,
527                                    CanonOutput* output,
528                                    Parsed* new_parsed);
529
530// Use for filesystem URLs.
531URL_EXPORT bool CanonicalizeFileSystemURL(const char* spec,
532                                          int spec_len,
533                                          const Parsed& parsed,
534                                          CharsetConverter* query_converter,
535                                          CanonOutput* output,
536                                          Parsed* new_parsed);
537URL_EXPORT bool CanonicalizeFileSystemURL(const base::char16* spec,
538                                          int spec_len,
539                                          const Parsed& parsed,
540                                          CharsetConverter* query_converter,
541                                          CanonOutput* output,
542                                          Parsed* new_parsed);
543
544// Use for path URLs such as javascript. This does not modify the path in any
545// way, for example, by escaping it.
546URL_EXPORT bool CanonicalizePathURL(const char* spec,
547                                    int spec_len,
548                                    const Parsed& parsed,
549                                    CanonOutput* output,
550                                    Parsed* new_parsed);
551URL_EXPORT bool CanonicalizePathURL(const base::char16* spec,
552                                    int spec_len,
553                                    const Parsed& parsed,
554                                    CanonOutput* output,
555                                    Parsed* new_parsed);
556
557// Use for mailto URLs. This "canonicalizes" the url into a path and query
558// component. It does not attempt to merge "to" fields. It uses UTF-8 for
559// the query encoding if there is a query. This is because a mailto URL is
560// really intended for an external mail program, and the encoding of a page,
561// etc. which would influence a query encoding normally are irrelevant.
562URL_EXPORT bool CanonicalizeMailtoURL(const char* spec,
563                                      int spec_len,
564                                      const Parsed& parsed,
565                                      CanonOutput* output,
566                                      Parsed* new_parsed);
567URL_EXPORT bool CanonicalizeMailtoURL(const base::char16* spec,
568                                      int spec_len,
569                                      const Parsed& parsed,
570                                      CanonOutput* output,
571                                      Parsed* new_parsed);
572
573// Part replacer --------------------------------------------------------------
574
575// Internal structure used for storing separate strings for each component.
576// The basic canonicalization functions use this structure internally so that
577// component replacement (different strings for different components) can be
578// treated on the same code path as regular canonicalization (the same string
579// for each component).
580//
581// A Parsed structure usually goes along with this. Those
582// components identify offsets within these strings, so that they can all be
583// in the same string, or spread arbitrarily across different ones.
584//
585// This structures does not own any data. It is the caller's responsibility to
586// ensure that the data the pointers point to stays in scope and is not
587// modified.
588template<typename CHAR>
589struct URLComponentSource {
590  // Constructor normally used by callers wishing to replace components. This
591  // will make them all NULL, which is no replacement. The caller would then
592  // override the components they want to replace.
593  URLComponentSource()
594      : scheme(NULL),
595        username(NULL),
596        password(NULL),
597        host(NULL),
598        port(NULL),
599        path(NULL),
600        query(NULL),
601        ref(NULL) {
602  }
603
604  // Constructor normally used internally to initialize all the components to
605  // point to the same spec.
606  explicit URLComponentSource(const CHAR* default_value)
607      : scheme(default_value),
608        username(default_value),
609        password(default_value),
610        host(default_value),
611        port(default_value),
612        path(default_value),
613        query(default_value),
614        ref(default_value) {
615  }
616
617  const CHAR* scheme;
618  const CHAR* username;
619  const CHAR* password;
620  const CHAR* host;
621  const CHAR* port;
622  const CHAR* path;
623  const CHAR* query;
624  const CHAR* ref;
625};
626
627// This structure encapsulates information on modifying a URL. Each component
628// may either be left unchanged, replaced, or deleted.
629//
630// By default, each component is unchanged. For those components that should be
631// modified, call either Set* or Clear* to modify it.
632//
633// The string passed to Set* functions DOES NOT GET COPIED AND MUST BE KEPT
634// IN SCOPE BY THE CALLER for as long as this object exists!
635//
636// Prefer the 8-bit replacement version if possible since it is more efficient.
637template<typename CHAR>
638class Replacements {
639 public:
640  Replacements() {
641  }
642
643  // Scheme
644  void SetScheme(const CHAR* s, const Component& comp) {
645    sources_.scheme = s;
646    components_.scheme = comp;
647  }
648  // Note: we don't have a ClearScheme since this doesn't make any sense.
649  bool IsSchemeOverridden() const { return sources_.scheme != NULL; }
650
651  // Username
652  void SetUsername(const CHAR* s, const Component& comp) {
653    sources_.username = s;
654    components_.username = comp;
655  }
656  void ClearUsername() {
657    sources_.username = Placeholder();
658    components_.username = Component();
659  }
660  bool IsUsernameOverridden() const { return sources_.username != NULL; }
661
662  // Password
663  void SetPassword(const CHAR* s, const Component& comp) {
664    sources_.password = s;
665    components_.password = comp;
666  }
667  void ClearPassword() {
668    sources_.password = Placeholder();
669    components_.password = Component();
670  }
671  bool IsPasswordOverridden() const { return sources_.password != NULL; }
672
673  // Host
674  void SetHost(const CHAR* s, const Component& comp) {
675    sources_.host = s;
676    components_.host = comp;
677  }
678  void ClearHost() {
679    sources_.host = Placeholder();
680    components_.host = Component();
681  }
682  bool IsHostOverridden() const { return sources_.host != NULL; }
683
684  // Port
685  void SetPort(const CHAR* s, const Component& comp) {
686    sources_.port = s;
687    components_.port = comp;
688  }
689  void ClearPort() {
690    sources_.port = Placeholder();
691    components_.port = Component();
692  }
693  bool IsPortOverridden() const { return sources_.port != NULL; }
694
695  // Path
696  void SetPath(const CHAR* s, const Component& comp) {
697    sources_.path = s;
698    components_.path = comp;
699  }
700  void ClearPath() {
701    sources_.path = Placeholder();
702    components_.path = Component();
703  }
704  bool IsPathOverridden() const { return sources_.path != NULL; }
705
706  // Query
707  void SetQuery(const CHAR* s, const Component& comp) {
708    sources_.query = s;
709    components_.query = comp;
710  }
711  void ClearQuery() {
712    sources_.query = Placeholder();
713    components_.query = Component();
714  }
715  bool IsQueryOverridden() const { return sources_.query != NULL; }
716
717  // Ref
718  void SetRef(const CHAR* s, const Component& comp) {
719    sources_.ref = s;
720    components_.ref = comp;
721  }
722  void ClearRef() {
723    sources_.ref = Placeholder();
724    components_.ref = Component();
725  }
726  bool IsRefOverridden() const { return sources_.ref != NULL; }
727
728  // Getters for the itnernal data. See the variables below for how the
729  // information is encoded.
730  const URLComponentSource<CHAR>& sources() const { return sources_; }
731  const Parsed& components() const { return components_; }
732
733 private:
734  // Returns a pointer to a static empty string that is used as a placeholder
735  // to indicate a component should be deleted (see below).
736  const CHAR* Placeholder() {
737    static const CHAR empty_string = 0;
738    return &empty_string;
739  }
740
741  // We support three states:
742  //
743  // Action                 | Source                Component
744  // -----------------------+--------------------------------------------------
745  // Don't change component | NULL                  (unused)
746  // Replace component      | (replacement string)  (replacement component)
747  // Delete component       | (non-NULL)            (invalid component: (0,-1))
748  //
749  // We use a pointer to the empty string for the source when the component
750  // should be deleted.
751  URLComponentSource<CHAR> sources_;
752  Parsed components_;
753};
754
755// The base must be an 8-bit canonical URL.
756URL_EXPORT bool ReplaceStandardURL(const char* base,
757                                   const Parsed& base_parsed,
758                                   const Replacements<char>& replacements,
759                                   CharsetConverter* query_converter,
760                                   CanonOutput* output,
761                                   Parsed* new_parsed);
762URL_EXPORT bool ReplaceStandardURL(
763    const char* base,
764    const Parsed& base_parsed,
765    const Replacements<base::char16>& replacements,
766    CharsetConverter* query_converter,
767    CanonOutput* output,
768    Parsed* new_parsed);
769
770// Filesystem URLs can only have the path, query, or ref replaced.
771// All other components will be ignored.
772URL_EXPORT bool ReplaceFileSystemURL(const char* base,
773                                     const Parsed& base_parsed,
774                                     const Replacements<char>& replacements,
775                                     CharsetConverter* query_converter,
776                                     CanonOutput* output,
777                                     Parsed* new_parsed);
778URL_EXPORT bool ReplaceFileSystemURL(
779    const char* base,
780    const Parsed& base_parsed,
781    const Replacements<base::char16>& replacements,
782    CharsetConverter* query_converter,
783    CanonOutput* output,
784    Parsed* new_parsed);
785
786// Replacing some parts of a file URL is not permitted. Everything except
787// the host, path, query, and ref will be ignored.
788URL_EXPORT bool ReplaceFileURL(const char* base,
789                               const Parsed& base_parsed,
790                               const Replacements<char>& replacements,
791                               CharsetConverter* query_converter,
792                               CanonOutput* output,
793                               Parsed* new_parsed);
794URL_EXPORT bool ReplaceFileURL(const char* base,
795                               const Parsed& base_parsed,
796                               const Replacements<base::char16>& replacements,
797                               CharsetConverter* query_converter,
798                               CanonOutput* output,
799                               Parsed* new_parsed);
800
801// Path URLs can only have the scheme and path replaced. All other components
802// will be ignored.
803URL_EXPORT bool ReplacePathURL(const char* base,
804                               const Parsed& base_parsed,
805                               const Replacements<char>& replacements,
806                               CanonOutput* output,
807                               Parsed* new_parsed);
808URL_EXPORT bool ReplacePathURL(const char* base,
809                               const Parsed& base_parsed,
810                               const Replacements<base::char16>& replacements,
811                               CanonOutput* output,
812                               Parsed* new_parsed);
813
814// Mailto URLs can only have the scheme, path, and query replaced.
815// All other components will be ignored.
816URL_EXPORT bool ReplaceMailtoURL(const char* base,
817                                 const Parsed& base_parsed,
818                                 const Replacements<char>& replacements,
819                                 CanonOutput* output,
820                                 Parsed* new_parsed);
821URL_EXPORT bool ReplaceMailtoURL(const char* base,
822                                 const Parsed& base_parsed,
823                                 const Replacements<base::char16>& replacements,
824                                 CanonOutput* output,
825                                 Parsed* new_parsed);
826
827// Relative URL ---------------------------------------------------------------
828
829// Given an input URL or URL fragment |fragment|, determines if it is a
830// relative or absolute URL and places the result into |*is_relative|. If it is
831// relative, the relevant portion of the URL will be placed into
832// |*relative_component| (there may have been trimmed whitespace, for example).
833// This value is passed to ResolveRelativeURL. If the input is not relative,
834// this value is UNDEFINED (it may be changed by the function).
835//
836// Returns true on success (we successfully determined the URL is relative or
837// not). Failure means that the combination of URLs doesn't make any sense.
838//
839// The base URL should always be canonical, therefore is ASCII.
840URL_EXPORT bool IsRelativeURL(const char* base,
841                              const Parsed& base_parsed,
842                              const char* fragment,
843                              int fragment_len,
844                              bool is_base_hierarchical,
845                              bool* is_relative,
846                              Component* relative_component);
847URL_EXPORT bool IsRelativeURL(const char* base,
848                              const Parsed& base_parsed,
849                              const base::char16* fragment,
850                              int fragment_len,
851                              bool is_base_hierarchical,
852                              bool* is_relative,
853                              Component* relative_component);
854
855// Given a canonical parsed source URL, a URL fragment known to be relative,
856// and the identified relevant portion of the relative URL (computed by
857// IsRelativeURL), this produces a new parsed canonical URL in |output| and
858// |out_parsed|.
859//
860// It also requires a flag indicating whether the base URL is a file: URL
861// which triggers additional logic.
862//
863// The base URL should be canonical and have a host (may be empty for file
864// URLs) and a path. If it doesn't have these, we can't resolve relative
865// URLs off of it and will return the base as the output with an error flag.
866// Becausee it is canonical is should also be ASCII.
867//
868// The query charset converter follows the same rules as CanonicalizeQuery.
869//
870// Returns true on success. On failure, the output will be "something
871// reasonable" that will be consistent and valid, just probably not what
872// was intended by the web page author or caller.
873URL_EXPORT bool ResolveRelativeURL(const char* base_url,
874                                   const Parsed& base_parsed,
875                                   bool base_is_file,
876                                   const char* relative_url,
877                                   const Component& relative_component,
878                                   CharsetConverter* query_converter,
879                                   CanonOutput* output,
880                                   Parsed* out_parsed);
881URL_EXPORT bool ResolveRelativeURL(const char* base_url,
882                                   const Parsed& base_parsed,
883                                   bool base_is_file,
884                                   const base::char16* relative_url,
885                                   const Component& relative_component,
886                                   CharsetConverter* query_converter,
887                                   CanonOutput* output,
888                                   Parsed* out_parsed);
889
890}  // namespace url
891
892#endif  // URL_URL_CANON_H_
893