Unify UUID/GUID generation code across base and blink

base/guid.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/guid.h"
 
 #include <stddef.h>
+#include <stdint.h>
 
+#include "base/rand_util.h"
 #include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 
 namespace base {
 
-bool IsValidGUID(const std::string& guid) {
+namespace {
+
+bool IsLowerHexDigit(char c) {
+  return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f');
+}
+
+bool IsValidGUIDInternal(const std::string& guid, bool strict) {
   const size_t kGUIDLength = 36U;
   if (guid.length() != kGUIDLength)
     return false;
 
   for (size_t i = 0; i < guid.length(); ++i) {
     char current = guid[i];
     if (i == 8 || i == 13 || i == 18 || i == 23) {
       if (current != '-')
         return false;
     } else {
-      if (!IsHexDigit(current))
+      if ((strict && !IsLowerHexDigit(current)) || !IsHexDigit(current))
         return false;
     }
   }
 
   return true;
 }
 
+}  // namespace
+
+std::string GenerateGUID() {
+  uint64_t sixteen_bytes[2] = {base::RandUint64(), base::RandUint64()};
+
+  // Set the GUID to version 4 as described in RFC 4122, section 4.4.
+  // The format of GUID version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx,
+  // where y is one of [8, 9, A, B].
+
+  // Clear the version bits and set the version to 4:
+  sixteen_bytes[0] &= 0xffffffffffff0fffULL;
+  sixteen_bytes[0] |= 0x0000000000004000ULL;
+
+  // Set the two most significant bits (bits 6 and 7) of the
+  // clock_seq_hi_and_reserved to zero and one, respectively:
+  sixteen_bytes[1] &= 0x3fffffffffffffffULL;
+  sixteen_bytes[1] |= 0x8000000000000000ULL;
+
+  return RandomDataToGUIDString(sixteen_bytes);
+}
+
+bool IsValidGUID(const std::string& guid) {
+  return IsValidGUIDInternal(guid, false /* strict */);
+}
+
+bool IsValidVersion4GUID(const std::string& guid) {
+  return IsValidGUIDInternal(guid, true /* strict */);
+}
+
+std::string RandomDataToGUIDString(const uint64_t bytes[2]) {
+  return StringPrintf("%08x-%04x-%04x-%01X%03x-%012llx",

[Mark Mentovai, 2016/04/22 13:01:46]

There’s a capital X in here that should be lowercase.

[kinuko, 2016/04/25 14:24:37]

Done.

+                      static_cast<unsigned int>(bytes[0] >> 32),
+                      static_cast<unsigned int>((bytes[0] >> 16) & 0x0000ffff),
+                      static_cast<unsigned int>(bytes[0] & 0x0000ffff),
+                      static_cast<unsigned int>(bytes[1] >> 60),

[Mark Mentovai, 2016/04/22 13:01:46]

I don’t see the reason to have bytes[1] >> 60 and (bytes[1] >> 48) & 0x0fff be
separated.

[kinuko, 2016/04/25 14:24:37]

Oops, you're right, done.

+                      static_cast<unsigned int>((bytes[1] >> 48) & 0x0fff),
+                      bytes[1] & 0x0000ffffffffffffULL);
+}
+
 }  // namespace base