Move googleurl into the Chrome repo.

url/url_canon.h

Index: url/url_canon.h
===================================================================
--- url/url_canon.h	(revision 0)
+++ url/url_canon.h	(revision 0)
@@ -0,0 +1,912 @@
+// 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.
+#ifndef GOOGLEURL_SRC_URL_CANON_H__
+#define GOOGLEURL_SRC_URL_CANON_H__
+
+#include <string.h>
+#include <stdlib.h>
+
+#include "base/string16.h"
+#include "googleurl/src/url_common.h"
+#include "googleurl/src/url_parse.h"
+
+namespace url_canon {
+
+// Canonicalizer output -------------------------------------------------------
+
+// Base class for the canonicalizer output, this maintains a buffer and
+// supports simple resizing and append operations on it.
+//
+// It is VERY IMPORTANT that no virtual function calls be made on the common
+// code path. We only have two virtual function calls, the destructor and a
+// resize function that is called when the existing buffer is not big enough.
+// The derived class is then in charge of setting up our buffer which we will
+// manage.
+template<typename T>
+class CanonOutputT {
+ public:
+  CanonOutputT() : buffer_(NULL), buffer_len_(0), cur_len_(0) {
+  }
+  virtual ~CanonOutputT() {
+  }
+
+  // Implemented to resize the buffer. This function should update the buffer
+  // pointer to point to the new buffer, and any old data up to |cur_len_| in
+  // the buffer must be copied over.
+  //
+  // The new size |sz| must be larger than buffer_len_.
+  virtual void Resize(int sz) = 0;
+
+  // Accessor for returning a character at a given position. The input offset
+  // must be in the valid range.
+  inline char at(int offset) const {
+    return buffer_[offset];
+  }
+
+  // Sets the character at the given position. The given position MUST be less
+  // than the length().
+  inline void set(int offset, int ch) {
+    buffer_[offset] = ch;
+  }
+
+  // Returns the number of characters currently in the buffer.
+  inline int length() const {
+    return cur_len_;
+  }
+
+  // Returns the current capacity of the buffer. The length() is the number of
+  // characters that have been declared to be written, but the capacity() is
+  // the number that can be written without reallocation. If the caller must
+  // write many characters at once, it can make sure there is enough capacity,
+  // write the data, then use set_size() to declare the new length().
+  int capacity() const {
+    return buffer_len_;
+  }
+
+  // Called by the user of this class to get the output. The output will NOT
+  // be NULL-terminated. Call length() to get the
+  // length.
+  const T* data() const {
+    return buffer_;
+  }
+  T* data() {
+    return buffer_;
+  }
+
+  // Shortens the URL to the new length. Used for "backing up" when processing
+  // relative paths. This can also be used if an external function writes a lot
+  // of data to the buffer (when using the "Raw" version below) beyond the end,
+  // to declare the new length.
+  //
+  // This MUST NOT be used to expand the size of the buffer beyond capacity().
+  void set_length(int new_len) {
+    cur_len_ = new_len;
+  }
+
+  // This is the most performance critical function, since it is called for
+  // every character.
+  void push_back(T ch) {
+    // In VC2005, putting this common case first speeds up execution
+    // dramatically because this branch is predicted as taken.
+    if (cur_len_ < buffer_len_) {
+      buffer_[cur_len_] = ch;
+      cur_len_++;
+      return;
+    }
+
+    // Grow the buffer to hold at least one more item. Hopefully we won't have
+    // to do this very often.
+    if (!Grow(1))
+      return;
+
+    // Actually do the insertion.
+    buffer_[cur_len_] = ch;
+    cur_len_++;
+  }
+
+  // Appends the given string to the output.
+  void Append(const T* str, int str_len) {
+    if (cur_len_ + str_len > buffer_len_) {
+      if (!Grow(cur_len_ + str_len - buffer_len_))
+        return;
+    }
+    for (int i = 0; i < str_len; i++)
+      buffer_[cur_len_ + i] = str[i];
+    cur_len_ += str_len;
+  }
+
+ protected:
+  // Grows the given buffer so that it can fit at least |min_additional|
+  // characters. Returns true if the buffer could be resized, false on OOM.
+  bool Grow(int min_additional) {
+    static const int kMinBufferLen = 16;
+    int new_len = (buffer_len_ == 0) ? kMinBufferLen : buffer_len_;
+    do {
+      if (new_len >= (1 << 30))  // Prevent overflow below.
+        return false;
+      new_len *= 2;
+    } while (new_len < buffer_len_ + min_additional);
+    Resize(new_len);
+    return true;
+  }
+
+  T* buffer_;
+  int buffer_len_;
+
+  // Used characters in the buffer.
+  int cur_len_;
+};
+
+// Simple implementation of the CanonOutput using new[]. This class
+// also supports a static buffer so if it is allocated on the stack, most
+// URLs can be canonicalized with no heap allocations.
+template<typename T, int fixed_capacity = 1024>
+class RawCanonOutputT : public CanonOutputT<T> {
+ public:
+  RawCanonOutputT() : CanonOutputT<T>() {
+    this->buffer_ = fixed_buffer_;
+    this->buffer_len_ = fixed_capacity;
+  }
+  virtual ~RawCanonOutputT() {
+    if (this->buffer_ != fixed_buffer_)
+      delete[] this->buffer_;
+  }
+
+  virtual void Resize(int sz) {
+    T* new_buf = new T[sz];
+    memcpy(new_buf, this->buffer_,
+           sizeof(T) * (this->cur_len_ < sz ? this->cur_len_ : sz));
+    if (this->buffer_ != fixed_buffer_)
+      delete[] this->buffer_;
+    this->buffer_ = new_buf;
+    this->buffer_len_ = sz;
+  }
+
+ protected:
+  T fixed_buffer_[fixed_capacity];
+};
+
+// Normally, all canonicalization output is in narrow characters. We support
+// the templates so it can also be used internally if a wide buffer is
+// required.
+typedef CanonOutputT<char> CanonOutput;
+typedef CanonOutputT<char16> CanonOutputW;
+
+template<int fixed_capacity>
+class RawCanonOutput : public RawCanonOutputT<char, fixed_capacity> {};
+template<int fixed_capacity>
+class RawCanonOutputW : public RawCanonOutputT<char16, fixed_capacity> {};
+
+// Character set converter ----------------------------------------------------
+//
+// Converts query strings into a custom encoding. The embedder can supply an
+// implementation of this class to interface with their own character set
+// conversion libraries.
+//
+// Embedders will want to see the unit test for the ICU version.
+
+class CharsetConverter {
+ public:
+  CharsetConverter() {}
+  virtual ~CharsetConverter() {}
+
+  // Converts the given input string from UTF-16 to whatever output format the
+  // converter supports. This is used only for the query encoding conversion,
+  // which does not fail. Instead, the converter should insert "invalid
+  // character" characters in the output for invalid sequences, and do the
+  // best it can.
+  //
+  // If the input contains a character not representable in the output
+  // character set, the converter should append the HTML entity sequence in
+  // decimal, (such as "&#20320;") with escaping of the ampersand, number
+  // sign, and semicolon (in the previous example it would be
+  // "%26%2320320%3B"). This rule is based on what IE does in this situation.
+  virtual void ConvertFromUTF16(const char16* input,
+                                int input_len,
+                                CanonOutput* output) = 0;
+};
+
+// Whitespace -----------------------------------------------------------------
+
+// Searches for whitespace that should be removed from the middle of URLs, and
+// removes it. Removed whitespace are tabs and newlines, but NOT spaces. Spaces
+// are preserved, which is what most browsers do. A pointer to the output will
+// be returned, and the length of that output will be in |output_len|.
+//
+// This should be called before parsing if whitespace removal is desired (which
+// it normally is when you are canonicalizing).
+//
+// If no whitespace is removed, this function will not use the buffer and will
+// return a pointer to the input, to avoid the extra copy. If modification is
+// required, the given |buffer| will be used and the returned pointer will
+// point to the beginning of the buffer.
+//
+// Therefore, callers should not use the buffer, since it may actuall be empty,
+// use the computed pointer and |*output_len| instead.
+GURL_API const char* RemoveURLWhitespace(const char* input, int input_len,
+                                         CanonOutputT<char>* buffer,
+                                         int* output_len);
+GURL_API const char16* RemoveURLWhitespace(const char16* input, int input_len,
+                                           CanonOutputT<char16>* buffer,
+                                           int* output_len);
+
+// IDN ------------------------------------------------------------------------
+
+// Converts the Unicode input representing a hostname to ASCII using IDN rules.
+// The output must fall in the ASCII range, but will be encoded in UTF-16.
+//
+// On success, the output will be filled with the ASCII host name and it will
+// return true. Unlike most other canonicalization functions, this assumes that
+// the output is empty. The beginning of the host will be at offset 0, and
+// the length of the output will be set to the length of the new host name.
+//
+// On error, returns false. The output in this case is undefined.
+GURL_API bool IDNToASCII(const char16* src, int src_len, CanonOutputW* output);
+
+// Piece-by-piece canonicalizers ----------------------------------------------
+//
+// These individual canonicalizers append the canonicalized versions of the
+// corresponding URL component to the given std::string. The spec and the
+// previously-identified range of that component are the input. The range of
+// the canonicalized component will be written to the output component.
+//
+// These functions all append to the output so they can be chained. Make sure
+// the output is empty when you start.
+//
+// These functions returns boolean values indicating success. On failure, they
+// will attempt to write something reasonable to the output so that, if
+// displayed to the user, they will recognise it as something that's messed up.
+// Nothing more should ever be done with these invalid URLs, however.
+
+// Scheme: Appends the scheme and colon to the URL. The output component will
+// indicate the range of characters up to but not including the colon.
+//
+// Canonical URLs always have a scheme. If the scheme is not present in the
+// input, this will just write the colon to indicate an empty scheme. Does not
+// append slashes which will be needed before any authority components for most
+// URLs.
+//
+// The 8-bit version requires UTF-8 encoding.
+GURL_API bool CanonicalizeScheme(const char* spec,
+                                 const url_parse::Component& scheme,
+                                 CanonOutput* output,
+                                 url_parse::Component* out_scheme);
+GURL_API bool CanonicalizeScheme(const char16* spec,
+                                 const url_parse::Component& scheme,
+                                 CanonOutput* output,
+                                 url_parse::Component* out_scheme);
+
+// User info: username/password. If present, this will add the delimiters so
+// the output will be "<username>:<password>@" or "<username>@". Empty
+// username/password pairs, or empty passwords, will get converted to
+// nonexistant in the canonical version.
+//
+// The components for the username and password refer to ranges in the
+// respective source strings. Usually, these will be the same string, which
+// is legal as long as the two components don't overlap.
+//
+// The 8-bit version requires UTF-8 encoding.
+GURL_API bool CanonicalizeUserInfo(const char* username_source,
+                                   const url_parse::Component& username,
+                                   const char* password_source,
+                                   const url_parse::Component& password,
+                                   CanonOutput* output,
+                                   url_parse::Component* out_username,
+                                   url_parse::Component* out_password);
+GURL_API bool CanonicalizeUserInfo(const char16* username_source,
+                                   const url_parse::Component& username,
+                                   const char16* password_source,
+                                   const url_parse::Component& password,
+                                   CanonOutput* output,
+                                   url_parse::Component* out_username,
+                                   url_parse::Component* out_password);
+
+
+// This structure holds detailed state exported from the IP/Host canonicalizers.
+// Additional fields may be added as callers require them.
+struct CanonHostInfo {
+  CanonHostInfo() : family(NEUTRAL), num_ipv4_components(0), out_host() {}
+
+  // Convenience function to test if family is an IP address.
+  bool IsIPAddress() const { return family == IPV4 || family == IPV6; }
+
+  // This field summarizes how the input was classified by the canonicalizer.
+  enum Family {
+    NEUTRAL,   // - Doesn't resemble an IP address.  As far as the IP
+               //   canonicalizer is concerned, it should be treated as a
+               //   hostname.
+    BROKEN,    // - Almost an IP, but was not canonicalized.  This could be an
+               //   IPv4 address where truncation occurred, or something
+               //   containing the special characters :[] which did not parse
+               //   as an IPv6 address.  Never attempt to connect to this
+               //   address, because it might actually succeed!
+    IPV4,      // - Successfully canonicalized as an IPv4 address.
+    IPV6,      // - Successfully canonicalized as an IPv6 address.
+  };
+  Family family;
+
+  // If |family| is IPV4, then this is the number of nonempty dot-separated
+  // components in the input text, from 1 to 4.  If |family| is not IPV4,
+  // this value is undefined.
+  int num_ipv4_components;
+
+  // Location of host within the canonicalized output.
+  // CanonicalizeIPAddress() only sets this field if |family| is IPV4 or IPV6.
+  // CanonicalizeHostVerbose() always sets it.
+  url_parse::Component out_host;
+
+  // |address| contains the parsed IP Address (if any) in its first
+  // AddressLength() bytes, in network order. If IsIPAddress() is false
+  // AddressLength() will return zero and the content of |address| is undefined.
+  unsigned char address[16];
+
+  // Convenience function to calculate the length of an IP address corresponding
+  // to the current IP version in |family|, if any. For use with |address|.
+  int AddressLength() const {
+    return family == IPV4 ? 4 : (family == IPV6 ? 16 : 0);
+  }
+};
+
+
+// Host.
+//
+// The 8-bit version requires UTF-8 encoding.  Use this version when you only
+// need to know whether canonicalization succeeded.
+GURL_API bool CanonicalizeHost(const char* spec,
+                               const url_parse::Component& host,
+                               CanonOutput* output,
+                               url_parse::Component* out_host);
+GURL_API bool CanonicalizeHost(const char16* spec,
+                               const url_parse::Component& host,
+                               CanonOutput* output,
+                               url_parse::Component* out_host);
+
+// Extended version of CanonicalizeHost, which returns additional information.
+// Use this when you need to know whether the hostname was an IP address.
+// A successful return is indicated by host_info->family != BROKEN.  See the
+// definition of CanonHostInfo above for details.
+GURL_API void CanonicalizeHostVerbose(const char* spec,
+                                      const url_parse::Component& host,
+                                      CanonOutput* output,
+                                      CanonHostInfo* host_info);
+GURL_API void CanonicalizeHostVerbose(const char16* spec,
+                                      const url_parse::Component& host,
+                                      CanonOutput* output,
+                                      CanonHostInfo* host_info);
+
+
+// IP addresses.
+//
+// Tries to interpret the given host name as an IPv4 or IPv6 address. If it is
+// an IP address, it will canonicalize it as such, appending it to |output|.
+// Additional status information is returned via the |*host_info| parameter.
+// See the definition of CanonHostInfo above for details.
+//
+// This is called AUTOMATICALLY from the host canonicalizer, which ensures that
+// the input is unescaped and name-prepped, etc. It should not normally be
+// necessary or wise to call this directly.
+GURL_API void CanonicalizeIPAddress(const char* spec,
+                                    const url_parse::Component& host,
+                                    CanonOutput* output,
+                                    CanonHostInfo* host_info);
+GURL_API void CanonicalizeIPAddress(const char16* spec,
+                                    const url_parse::Component& host,
+                                    CanonOutput* output,
+                                    CanonHostInfo* host_info);
+
+// Port: this function will add the colon for the port if a port is present.
+// The caller can pass url_parse::PORT_UNSPECIFIED as the
+// default_port_for_scheme argument if there is no default port.
+//
+// The 8-bit version requires UTF-8 encoding.
+GURL_API bool CanonicalizePort(const char* spec,
+                               const url_parse::Component& port,
+                               int default_port_for_scheme,
+                               CanonOutput* output,
+                               url_parse::Component* out_port);
+GURL_API bool CanonicalizePort(const char16* spec,
+                               const url_parse::Component& port,
+                               int default_port_for_scheme,
+                               CanonOutput* output,
+                               url_parse::Component* out_port);
+
+// Returns the default port for the given canonical scheme, or PORT_UNSPECIFIED
+// if the scheme is unknown.
+GURL_API int DefaultPortForScheme(const char* scheme, int scheme_len);
+
+// Path. If the input does not begin in a slash (including if the input is
+// empty), we'll prepend a slash to the path to make it canonical.
+//
+// The 8-bit version assumes UTF-8 encoding, but does not verify the validity
+// of the UTF-8 (i.e., you can have invalid UTF-8 sequences, invalid
+// characters, etc.). Normally, URLs will come in as UTF-16, so this isn't
+// an issue. Somebody giving us an 8-bit path is responsible for generating
+// the path that the server expects (we'll escape high-bit characters), so
+// if something is invalid, it's their problem.
+GURL_API bool CanonicalizePath(const char* spec,
+                               const url_parse::Component& path,
+                               CanonOutput* output,
+                               url_parse::Component* out_path);
+GURL_API bool CanonicalizePath(const char16* spec,
+                               const url_parse::Component& path,
+                               CanonOutput* output,
+                               url_parse::Component* out_path);
+
+// Canonicalizes the input as a file path. This is like CanonicalizePath except
+// that it also handles Windows drive specs. For example, the path can begin
+// with "c|\" and it will get properly canonicalized to "C:/".
+// The string will be appended to |*output| and |*out_path| will be updated.
+//
+// The 8-bit version requires UTF-8 encoding.
+GURL_API bool FileCanonicalizePath(const char* spec,
+                                   const url_parse::Component& path,
+                                   CanonOutput* output,
+                                   url_parse::Component* out_path);
+GURL_API bool FileCanonicalizePath(const char16* spec,
+                                   const url_parse::Component& path,
+                                   CanonOutput* output,
+                                   url_parse::Component* out_path);
+
+// Query: Prepends the ? if needed.
+//
+// The 8-bit version requires the input to be UTF-8 encoding. Incorrectly
+// encoded characters (in UTF-8 or UTF-16) will be replaced with the Unicode
+// "invalid character." This function can not fail, we always just try to do
+// our best for crazy input here since web pages can set it themselves.
+//
+// This will convert the given input into the output encoding that the given
+// character set converter object provides. The converter will only be called
+// if necessary, for ASCII input, no conversions are necessary.
+//
+// The converter can be NULL. In this case, the output encoding will be UTF-8.
+GURL_API void CanonicalizeQuery(const char* spec,
+                                const url_parse::Component& query,
+                                CharsetConverter* converter,
+                                CanonOutput* output,
+                                url_parse::Component* out_query);
+GURL_API void CanonicalizeQuery(const char16* spec,
+                                const url_parse::Component& query,
+                                CharsetConverter* converter,
+                                CanonOutput* output,
+                                url_parse::Component* out_query);
+
+// Ref: Prepends the # if needed. The output will be UTF-8 (this is the only
+// canonicalizer that does not produce ASCII output). The output is
+// guaranteed to be valid UTF-8.
+//
+// This function will not fail. If the input is invalid UTF-8/UTF-16, we'll use
+// the "Unicode replacement character" for the confusing bits and copy the rest.
+GURL_API void CanonicalizeRef(const char* spec,
+                              const url_parse::Component& path,
+                              CanonOutput* output,
+                              url_parse::Component* out_path);
+GURL_API void CanonicalizeRef(const char16* spec,
+                              const url_parse::Component& path,
+                              CanonOutput* output,
+                              url_parse::Component* out_path);
+
+// Full canonicalizer ---------------------------------------------------------
+//
+// These functions replace any string contents, rather than append as above.
+// See the above piece-by-piece functions for information specific to
+// canonicalizing individual components.
+//
+// The output will be ASCII except the reference fragment, which may be UTF-8.
+//
+// The 8-bit versions require UTF-8 encoding.
+
+// Use for standard URLs with authorities and paths.
+GURL_API bool CanonicalizeStandardURL(const char* spec,
+                                      int spec_len,
+                                      const url_parse::Parsed& parsed,
+                                      CharsetConverter* query_converter,
+                                      CanonOutput* output,
+                                      url_parse::Parsed* new_parsed);
+GURL_API bool CanonicalizeStandardURL(const char16* spec,
+                                      int spec_len,
+                                      const url_parse::Parsed& parsed,
+                                      CharsetConverter* query_converter,
+                                      CanonOutput* output,
+                                      url_parse::Parsed* new_parsed);
+
+// Use for file URLs.
+GURL_API bool CanonicalizeFileURL(const char* spec,
+                                  int spec_len,
+                                  const url_parse::Parsed& parsed,
+                                  CharsetConverter* query_converter,
+                                  CanonOutput* output,
+                                  url_parse::Parsed* new_parsed);
+GURL_API bool CanonicalizeFileURL(const char16* spec,
+                                  int spec_len,
+                                  const url_parse::Parsed& parsed,
+                                  CharsetConverter* query_converter,
+                                  CanonOutput* output,
+                                  url_parse::Parsed* new_parsed);
+
+// Use for filesystem URLs.
+GURL_API bool CanonicalizeFileSystemURL(const char* spec,
+                                        int spec_len,
+                                        const url_parse::Parsed& parsed,
+                                        CharsetConverter* query_converter,
+                                        CanonOutput* output,
+                                        url_parse::Parsed* new_parsed);
+GURL_API bool CanonicalizeFileSystemURL(const char16* spec,
+                                        int spec_len,
+                                        const url_parse::Parsed& parsed,
+                                        CharsetConverter* query_converter,
+                                        CanonOutput* output,
+                                        url_parse::Parsed* new_parsed);
+
+// Use for path URLs such as javascript. This does not modify the path in any
+// way, for example, by escaping it.
+GURL_API bool CanonicalizePathURL(const char* spec,
+                                  int spec_len,
+                                  const url_parse::Parsed& parsed,
+                                  CanonOutput* output,
+                                  url_parse::Parsed* new_parsed);
+GURL_API bool CanonicalizePathURL(const char16* spec,
+                                  int spec_len,
+                                  const url_parse::Parsed& parsed,
+                                  CanonOutput* output,
+                                  url_parse::Parsed* new_parsed);
+
+// Use for mailto URLs. This "canonicalizes" the url into a path and query
+// component. It does not attempt to merge "to" fields. It uses UTF-8 for
+// the query encoding if there is a query. This is because a mailto URL is
+// really intended for an external mail program, and the encoding of a page,
+// etc. which would influence a query encoding normally are irrelevant.
+GURL_API bool CanonicalizeMailtoURL(const char* spec,
+                                    int spec_len,
+                                    const url_parse::Parsed& parsed,
+                                    CanonOutput* output,
+                                    url_parse::Parsed* new_parsed);
+GURL_API bool CanonicalizeMailtoURL(const char16* spec,
+                                    int spec_len,
+                                    const url_parse::Parsed& parsed,
+                                    CanonOutput* output,
+                                    url_parse::Parsed* new_parsed);
+
+// Part replacer --------------------------------------------------------------
+
+// Internal structure used for storing separate strings for each component.
+// The basic canonicalization functions use this structure internally so that
+// component replacement (different strings for different components) can be
+// treated on the same code path as regular canonicalization (the same string
+// for each component).
+//
+// A url_parse::Parsed structure usually goes along with this. Those
+// components identify offsets within these strings, so that they can all be
+// in the same string, or spread arbitrarily across different ones.
+//
+// This structures does not own any data. It is the caller's responsibility to
+// ensure that the data the pointers point to stays in scope and is not
+// modified.
+template<typename CHAR>
+struct URLComponentSource {
+  // Constructor normally used by callers wishing to replace components. This
+  // will make them all NULL, which is no replacement. The caller would then
+  // override the components they want to replace.
+  URLComponentSource()
+      : scheme(NULL),
+        username(NULL),
+        password(NULL),
+        host(NULL),
+        port(NULL),
+        path(NULL),
+        query(NULL),
+        ref(NULL) {
+  }
+
+  // Constructor normally used internally to initialize all the components to
+  // point to the same spec.
+  explicit URLComponentSource(const CHAR* default_value)
+      : scheme(default_value),
+        username(default_value),
+        password(default_value),
+        host(default_value),
+        port(default_value),
+        path(default_value),
+        query(default_value),
+        ref(default_value) {
+  }
+
+  const CHAR* scheme;
+  const CHAR* username;
+  const CHAR* password;
+  const CHAR* host;
+  const CHAR* port;
+  const CHAR* path;
+  const CHAR* query;
+  const CHAR* ref;
+};
+
+// This structure encapsulates information on modifying a URL. Each component
+// may either be left unchanged, replaced, or deleted.
+//
+// By default, each component is unchanged. For those components that should be
+// modified, call either Set* or Clear* to modify it.
+//
+// The string passed to Set* functions DOES NOT GET COPIED AND MUST BE KEPT
+// IN SCOPE BY THE CALLER for as long as this object exists!
+//
+// Prefer the 8-bit replacement version if possible since it is more efficient.
+template<typename CHAR>
+class Replacements {
+ public:
+  Replacements() {
+  }
+
+  // Scheme
+  void SetScheme(const CHAR* s, const url_parse::Component& comp) {
+    sources_.scheme = s;
+    components_.scheme = comp;
+  }
+  // Note: we don't have a ClearScheme since this doesn't make any sense.
+  bool IsSchemeOverridden() const { return sources_.scheme != NULL; }
+
+  // Username
+  void SetUsername(const CHAR* s, const url_parse::Component& comp) {
+    sources_.username = s;
+    components_.username = comp;
+  }
+  void ClearUsername() {
+    sources_.username = Placeholder();
+    components_.username = url_parse::Component();
+  }
+  bool IsUsernameOverridden() const { return sources_.username != NULL; }
+
+  // Password
+  void SetPassword(const CHAR* s, const url_parse::Component& comp) {
+    sources_.password = s;
+    components_.password = comp;
+  }
+  void ClearPassword() {
+    sources_.password = Placeholder();
+    components_.password = url_parse::Component();
+  }
+  bool IsPasswordOverridden() const { return sources_.password != NULL; }
+
+  // Host
+  void SetHost(const CHAR* s, const url_parse::Component& comp) {
+    sources_.host = s;
+    components_.host = comp;
+  }
+  void ClearHost() {
+    sources_.host = Placeholder();
+    components_.host = url_parse::Component();
+  }
+  bool IsHostOverridden() const { return sources_.host != NULL; }
+
+  // Port
+  void SetPort(const CHAR* s, const url_parse::Component& comp) {
+    sources_.port = s;
+    components_.port = comp;
+  }
+  void ClearPort() {
+    sources_.port = Placeholder();
+    components_.port = url_parse::Component();
+  }
+  bool IsPortOverridden() const { return sources_.port != NULL; }
+
+  // Path
+  void SetPath(const CHAR* s, const url_parse::Component& comp) {
+    sources_.path = s;
+    components_.path = comp;
+  }
+  void ClearPath() {
+    sources_.path = Placeholder();
+    components_.path = url_parse::Component();
+  }
+  bool IsPathOverridden() const { return sources_.path != NULL; }
+
+  // Query
+  void SetQuery(const CHAR* s, const url_parse::Component& comp) {
+    sources_.query = s;
+    components_.query = comp;
+  }
+  void ClearQuery() {
+    sources_.query = Placeholder();
+    components_.query = url_parse::Component();
+  }
+  bool IsQueryOverridden() const { return sources_.query != NULL; }
+
+  // Ref
+  void SetRef(const CHAR* s, const url_parse::Component& comp) {
+    sources_.ref = s;
+    components_.ref = comp;
+  }
+  void ClearRef() {
+    sources_.ref = Placeholder();
+    components_.ref = url_parse::Component();
+  }
+  bool IsRefOverridden() const { return sources_.ref != NULL; }
+
+  // Getters for the itnernal data. See the variables below for how the
+  // information is encoded.
+  const URLComponentSource<CHAR>& sources() const { return sources_; }
+  const url_parse::Parsed& components() const { return components_; }
+
+ private:
+  // Returns a pointer to a static empty string that is used as a placeholder
+  // to indicate a component should be deleted (see below).
+  const CHAR* Placeholder() {
+    static const CHAR empty_string = 0;
+    return &empty_string;
+  }
+
+  // We support three states:
+  //
+  // Action                 | Source                Component
+  // -----------------------+--------------------------------------------------
+  // Don't change component | NULL                  (unused)
+  // Replace component      | (replacement string)  (replacement component)
+  // Delete component       | (non-NULL)            (invalid component: (0,-1))
+  //
+  // We use a pointer to the empty string for the source when the component
+  // should be deleted.
+  URLComponentSource<CHAR> sources_;
+  url_parse::Parsed components_;
+};
+
+// The base must be an 8-bit canonical URL.
+GURL_API bool ReplaceStandardURL(const char* base,
+                                 const url_parse::Parsed& base_parsed,
+                                 const Replacements<char>& replacements,
+                                 CharsetConverter* query_converter,
+                                 CanonOutput* output,
+                                 url_parse::Parsed* new_parsed);
+GURL_API bool ReplaceStandardURL(const char* base,
+                                 const url_parse::Parsed& base_parsed,
+                                 const Replacements<char16>& replacements,
+                                 CharsetConverter* query_converter,
+                                 CanonOutput* output,
+                                 url_parse::Parsed* new_parsed);
+
+// Filesystem URLs can only have the path, query, or ref replaced.
+// All other components will be ignored.
+GURL_API bool ReplaceFileSystemURL(const char* base,
+                                   const url_parse::Parsed& base_parsed,
+                                   const Replacements<char>& replacements,
+                                   CharsetConverter* query_converter,
+                                   CanonOutput* output,
+                                   url_parse::Parsed* new_parsed);
+GURL_API bool ReplaceFileSystemURL(const char* base,
+                                   const url_parse::Parsed& base_parsed,
+                                   const Replacements<char16>& replacements,
+                                   CharsetConverter* query_converter,
+                                   CanonOutput* output,
+                                   url_parse::Parsed* new_parsed);
+
+// Replacing some parts of a file URL is not permitted. Everything except
+// the host, path, query, and ref will be ignored.
+GURL_API bool ReplaceFileURL(const char* base,
+                             const url_parse::Parsed& base_parsed,
+                             const Replacements<char>& replacements,
+                             CharsetConverter* query_converter,
+                             CanonOutput* output,
+                             url_parse::Parsed* new_parsed);
+GURL_API bool ReplaceFileURL(const char* base,
+                             const url_parse::Parsed& base_parsed,
+                             const Replacements<char16>& replacements,
+                             CharsetConverter* query_converter,
+                             CanonOutput* output,
+                             url_parse::Parsed* new_parsed);
+
+// Path URLs can only have the scheme and path replaced. All other components
+// will be ignored.
+GURL_API bool ReplacePathURL(const char* base,
+                             const url_parse::Parsed& base_parsed,
+                             const Replacements<char>& replacements,
+                             CanonOutput* output,
+                             url_parse::Parsed* new_parsed);
+GURL_API bool ReplacePathURL(const char* base,
+                             const url_parse::Parsed& base_parsed,
+                             const Replacements<char16>& replacements,
+                             CanonOutput* output,
+                             url_parse::Parsed* new_parsed);
+
+// Mailto URLs can only have the scheme, path, and query replaced.
+// All other components will be ignored.
+GURL_API bool ReplaceMailtoURL(const char* base,
+                               const url_parse::Parsed& base_parsed,
+                               const Replacements<char>& replacements,
+                               CanonOutput* output,
+                               url_parse::Parsed* new_parsed);
+GURL_API bool ReplaceMailtoURL(const char* base,
+                               const url_parse::Parsed& base_parsed,
+                               const Replacements<char16>& replacements,
+                               CanonOutput* output,
+                               url_parse::Parsed* new_parsed);
+
+// Relative URL ---------------------------------------------------------------
+
+// Given an input URL or URL fragment |fragment|, determines if it is a
+// relative or absolute URL and places the result into |*is_relative|. If it is
+// relative, the relevant portion of the URL will be placed into
+// |*relative_component| (there may have been trimmed whitespace, for example).
+// This value is passed to ResolveRelativeURL. If the input is not relative,
+// this value is UNDEFINED (it may be changed by the function).
+//
+// Returns true on success (we successfully determined the URL is relative or
+// not). Failure means that the combination of URLs doesn't make any sense.
+//
+// The base URL should always be canonical, therefore is ASCII.
+GURL_API bool IsRelativeURL(const char* base,
+                            const url_parse::Parsed& base_parsed,
+                            const char* fragment,
+                            int fragment_len,
+                            bool is_base_hierarchical,
+                            bool* is_relative,
+                            url_parse::Component* relative_component);
+GURL_API bool IsRelativeURL(const char* base,
+                            const url_parse::Parsed& base_parsed,
+                            const char16* fragment,
+                            int fragment_len,
+                            bool is_base_hierarchical,
+                            bool* is_relative,
+                            url_parse::Component* relative_component);
+
+// Given a canonical parsed source URL, a URL fragment known to be relative,
+// and the identified relevant portion of the relative URL (computed by
+// IsRelativeURL), this produces a new parsed canonical URL in |output| and
+// |out_parsed|.
+//
+// It also requires a flag indicating whether the base URL is a file: URL
+// which triggers additional logic.
+//
+// The base URL should be canonical and have a host (may be empty for file
+// URLs) and a path. If it doesn't have these, we can't resolve relative
+// URLs off of it and will return the base as the output with an error flag.
+// Becausee it is canonical is should also be ASCII.
+//
+// The query charset converter follows the same rules as CanonicalizeQuery.
+//
+// Returns true on success. On failure, the output will be "something
+// reasonable" that will be consistent and valid, just probably not what
+// was intended by the web page author or caller.
+GURL_API bool ResolveRelativeURL(const char* base_url,
+                                 const url_parse::Parsed& base_parsed,
+                                 bool base_is_file,
+                                 const char* relative_url,
+                                 const url_parse::Component& relative_component,
+                                 CharsetConverter* query_converter,
+                                 CanonOutput* output,
+                                 url_parse::Parsed* out_parsed);
+GURL_API bool ResolveRelativeURL(const char* base_url,
+                                 const url_parse::Parsed& base_parsed,
+                                 bool base_is_file,
+                                 const char16* relative_url,
+                                 const url_parse::Component& relative_component,
+                                 CharsetConverter* query_converter,
+                                 CanonOutput* output,
+                                 url_parse::Parsed* out_parsed);
+
+}  // namespace url_canon
+
+#endif  // GOOGLEURL_SRC_URL_CANON_H__
Property changes on: url/url_canon.h
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Added: svn:eol-style
   + LF