Add "x"s in the end of a stripped IPv6 address string.

webrtc/base/ipaddress.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #if defined(WEBRTC_POSIX)
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #ifdef OPENBSD
 #include <netinet/in_systm.h>
 #endif
 #ifndef __native_client__
 #include <netinet/ip.h>
 #endif
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <unistd.h>
 #endif
 
 #include <stdio.h>
 
 #include "webrtc/base/ipaddress.h"
 #include "webrtc/base/byteorder.h"
+#include "webrtc/base/checks.h"
 #include "webrtc/base/nethelpers.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/win32.h"
 
 namespace rtc {
 
 // Prefixes used for categorizing IPv6 addresses.
 static const in6_addr kV4MappedPrefix = {{{0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                                            0xFF, 0xFF, 0}}};
 static const in6_addr k6To4Prefix = {{{0x20, 0x02, 0}}};
@@ skipping 110 matching lines @@
     case AF_INET: {
       std::string address = ToString();
       size_t find_pos = address.rfind('.');
       if (find_pos == std::string::npos)
         return std::string();
       address.resize(find_pos);
       address += ".x";
       return address;
     }
     case AF_INET6: {
-      // TODO(grunell): Return a string of format 1:2:3:x:x:x:x:x or such
-      // instead of zeroing out.
-      return TruncateIP(*this, 128 - 80).ToString();
+      // Remove the last 5 groups (80 bits).
+      std::string address = TruncateIP(*this, 128 - 80).ToString();
+
+      // If all three remaining groups are written out explicitly in the string,
+      // remove one of the two trailing colons before appending the stripped
+      // groups as "x"s. There should be max 4 colons (2 between the 3 groups +
+      // 2 trailing) in the truncated address string.
+      size_t number_of_colons = std::count(address.begin(), address.end(), ':');
+      RTC_CHECK_LE(number_of_colons, 4u);
+      if (number_of_colons > 3)
+        address.resize(address.length() - 1);
+
+      return address + "x:x:x:x:x";
     }
   }
   return std::string();
 #endif
 }
 
 IPAddress IPAddress::Normalized() const {
   if (family_ != AF_INET6) {
     return *this;
   }
@@ skipping 334 matching lines @@
   if (family == AF_INET) {
     return rtc::IPAddress(INADDR_ANY);
   }
   if (family == AF_INET6) {
     return rtc::IPAddress(in6addr_any);
   }
   return rtc::IPAddress();
 }
 
 }  // Namespace rtc