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      1 // Copyright (c) 2006-2008 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 // NOTE: based loosely on mozilla's nsDataChannel.cpp
      6 
      7 #include <algorithm>
      8 
      9 #include "net/base/data_url.h"
     10 
     11 #include "base/base64.h"
     12 #include "base/string_util.h"
     13 #include "googleurl/src/gurl.h"
     14 #include "net/base/escape.h"
     15 
     16 namespace net {
     17 
     18 // static
     19 bool DataURL::Parse(const GURL& url, std::string* mime_type,
     20                     std::string* charset, std::string* data) {
     21   std::string::const_iterator begin = url.spec().begin();
     22   std::string::const_iterator end = url.spec().end();
     23 
     24   std::string::const_iterator after_colon = std::find(begin, end, ':');
     25   if (after_colon == end)
     26     return false;
     27   ++after_colon;
     28 
     29   // first, find the start of the data
     30   std::string::const_iterator comma = std::find(after_colon, end, ',');
     31   if (comma == end)
     32     return false;
     33 
     34   const char kBase64Tag[] = ";base64";
     35   std::string::const_iterator it =
     36       std::search(after_colon, comma, kBase64Tag,
     37                   kBase64Tag + sizeof(kBase64Tag)-1);
     38 
     39   bool base64_encoded = (it != comma);
     40 
     41   if (comma != after_colon) {
     42     // everything else is content type
     43     std::string::const_iterator semi_colon = std::find(after_colon, comma, ';');
     44     if (semi_colon != after_colon) {
     45       mime_type->assign(after_colon, semi_colon);
     46       StringToLowerASCII(mime_type);
     47     }
     48     if (semi_colon != comma) {
     49       const char kCharsetTag[] = "charset=";
     50       it = std::search(semi_colon + 1, comma, kCharsetTag,
     51                        kCharsetTag + sizeof(kCharsetTag)-1);
     52       if (it != comma)
     53         charset->assign(it + sizeof(kCharsetTag)-1, comma);
     54     }
     55   }
     56 
     57   // fallback to defaults if nothing specified in the URL:
     58   if (mime_type->empty())
     59     mime_type->assign("text/plain");
     60   if (charset->empty())
     61     charset->assign("US-ASCII");
     62 
     63   // The caller may not be interested in receiving the data.
     64   if (!data)
     65     return true;
     66 
     67   // Preserve spaces if dealing with text or xml input, same as mozilla:
     68   //   https://bugzilla.mozilla.org/show_bug.cgi?id=138052
     69   // but strip them otherwise:
     70   //   https://bugzilla.mozilla.org/show_bug.cgi?id=37200
     71   // (Spaces in a data URL should be escaped, which is handled below, so any
     72   // spaces now are wrong. People expect to be able to enter them in the URL
     73   // bar for text, and it can't hurt, so we allow it.)
     74   std::string temp_data = std::string(comma + 1, end);
     75 
     76   // For base64, we may have url-escaped whitespace which is not part
     77   // of the data, and should be stripped. Otherwise, the escaped whitespace
     78   // could be part of the payload, so don't strip it.
     79   if (base64_encoded) {
     80     temp_data = UnescapeURLComponent(temp_data,
     81         UnescapeRule::SPACES | UnescapeRule::URL_SPECIAL_CHARS |
     82         UnescapeRule::CONTROL_CHARS);
     83   }
     84 
     85   // Strip whitespace.
     86   if (base64_encoded || !(mime_type->compare(0, 5, "text/") == 0 ||
     87                           mime_type->find("xml") != std::string::npos)) {
     88     temp_data.erase(std::remove_if(temp_data.begin(), temp_data.end(),
     89                                    IsAsciiWhitespace<wchar_t>),
     90                     temp_data.end());
     91   }
     92 
     93   if (!base64_encoded) {
     94     temp_data = UnescapeURLComponent(temp_data,
     95         UnescapeRule::SPACES | UnescapeRule::URL_SPECIAL_CHARS |
     96         UnescapeRule::CONTROL_CHARS);
     97   }
     98 
     99   if (base64_encoded)
    100     return base::Base64Decode(temp_data, data);
    101 
    102   temp_data.swap(*data);
    103   return true;
    104 }
    105 
    106 }  // namespace net
    107