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      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 "chrome/browser/history/url_utils.h"
      6 
      7 #include <algorithm>
      8 
      9 namespace history {
     10 
     11 namespace {
     12 
     13 // Comparator to enforce '\0' < '?' < '#' < '/' < other characters.
     14 int GetURLCharPriority(char ch) {
     15   switch (ch) {
     16     case '\0': return 0;
     17     case '?': return 1;
     18     case '#': return 2;
     19     case '/': return 3;
     20   }
     21   return 4;
     22 }
     23 
     24 }  // namespace
     25 
     26 // Instead of splitting URLs and extract path components, we can implement
     27 // CanonicalURLStringCompare() using string operations only. The key idea is,
     28 // treating '/' to be less than any valid path characters would make it behave
     29 // as a separator, so e.g., "test" < "test-case" would be enforced by
     30 // "test/..." < "test-case/...". We also force "?" < "/", so "test?query" <
     31 // "test/stuff". Since the routine is merely lexicographical string comparison
     32 // with remapping of chracter ordering, so it is a valid strict-weak ordering.
     33 bool CanonicalURLStringCompare(const std::string& s1, const std::string& s2) {
     34   const std::string::value_type* ch1 = s1.c_str();
     35   const std::string::value_type* ch2 = s2.c_str();
     36   while (*ch1 && *ch2 && *ch1 == *ch2) {
     37     ++ch1;
     38     ++ch2;
     39   }
     40   int pri_diff = GetURLCharPriority(*ch1) - GetURLCharPriority(*ch2);
     41   // We want false to be returned if |pri_diff| > 0.
     42   return (pri_diff != 0) ? pri_diff < 0 : *ch1 < *ch2;
     43 }
     44 
     45 bool HaveSameSchemeHostAndPort(const GURL&url1, const GURL& url2) {
     46   return url1.scheme() == url2.scheme() && url1.host() == url2.host() &&
     47       url1.port() == url2.port();
     48 }
     49 
     50 bool IsPathPrefix(const std::string& p1, const std::string& p2) {
     51   if (p1.length() > p2.length())
     52     return false;
     53   std::pair<std::string::const_iterator, std::string::const_iterator>
     54       first_diff = std::mismatch(p1.begin(), p1.end(), p2.begin());
     55   // Necessary condition: |p1| is a string prefix of |p2|.
     56   if (first_diff.first != p1.end())
     57     return false;  // E.g.: (|p1| = "/test", |p2| = "/exam") => false.
     58 
     59   // |p1| is string prefix.
     60   if (first_diff.second == p2.end())  // Is exact match?
     61     return true;  // E.g.: ("/test", "/test") => true.
     62   // |p1| is strict string prefix, check full match of last path component.
     63   if (!p1.empty() && *p1.rbegin() == '/')  // Ends in '/'?
     64     return true;  // E.g.: ("/test/", "/test/stuff") => true.
     65 
     66   // Finally, |p1| does not end in "/": check first extra character in |p2|.
     67   // E.g.: ("/test", "/test/stuff") => true; ("/test", "/testing") => false.
     68   return *(first_diff.second) == '/';
     69 }
     70 
     71 GURL ToggleHTTPAndHTTPS(const GURL& url) {
     72   std::string new_scheme;
     73   if (url.SchemeIs("http"))
     74     new_scheme = "https";
     75   else if (url.SchemeIs("https"))
     76     new_scheme = "http";
     77   else
     78     return GURL::EmptyGURL();
     79   url_parse::Component comp;
     80   comp.len = new_scheme.length();
     81   GURL::Replacements replacement;
     82   replacement.SetScheme(new_scheme.c_str(), comp);
     83   return url.ReplaceComponents(replacement);
     84 }
     85 
     86 }  // namespace history
     87