Make GUID generation on POSIX compliant with GUID v4 format.

base/guid_unittest.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 <limits>
 
 #include "base/strings/string_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #if defined(OS_POSIX)
+
+namespace {
+
+bool IsGUIDv4(const std::string& guid) {
+  // The format of GUID version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx,
+  // where y is one of [8, 9, A, B].
+  return base::IsValidGUID(guid) && guid[14] == '4' &&
+         (guid[19] == '8' || guid[19] == '9' || guid[19] == 'A' ||
+          guid[19] == 'a' || guid[19] == 'B' || guid[19] == 'b');
+}
+
+}  // namespace
+
+
 TEST(GUIDTest, GUIDGeneratesAllZeroes) {
   uint64 bytes[] = { 0, 0 };
   std::string clientid = base::RandomDataToGUIDString(bytes);
   EXPECT_EQ("00000000-0000-0000-0000-000000000000", clientid);
 }
 
 TEST(GUIDTest, GUIDGeneratesCorrectly) {
   uint64 bytes[] = { 0x0123456789ABCDEFULL, 0xFEDCBA9876543210ULL };
   std::string clientid = base::RandomDataToGUIDString(bytes);
   EXPECT_EQ("01234567-89AB-CDEF-FEDC-BA9876543210", clientid);
@@ skipping 11 matching lines @@
 }
 
 TEST(GUIDTest, GUIDBasicUniqueness) {
   const int kIterations = 10;
   for (int it = 0; it < kIterations; ++it) {
     std::string guid1 = base::GenerateGUID();
     std::string guid2 = base::GenerateGUID();
     EXPECT_EQ(36U, guid1.length());
     EXPECT_EQ(36U, guid2.length());
     EXPECT_NE(guid1, guid2);
+#if defined(OS_POSIX)
+    EXPECT_TRUE(IsGUIDv4(guid1));
+    EXPECT_TRUE(IsGUIDv4(guid2));
+#endif
   }
 }