Base: Make RegistryOverrideManager support sharded/parallel tests.

base/test/test_reg_util_win.cc

 // Copyright (c) 2011 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/test/test_reg_util_win.h"
 
+#include "base/guid.h"
 #include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace registry_util {
 
-const wchar_t RegistryOverrideManager::kTempTestKeyPath[] =
-    L"Software\\Chromium\\TempTestKeys";
+namespace {
+
+const wchar_t kTimestampDelimiter[] = L"$";
+const wchar_t kTempTestKeyPath[] = L"Software\\Chromium\\TempTestKeys";
+
+void DeleteStaleTestKeys(const base::Time& now, const string16& test_key_root) {
+  base::win::RegKey test_root_key;
+  if (test_root_key.Open(HKEY_CURRENT_USER,
+                         test_key_root.c_str(),
+                         KEY_ALL_ACCESS) != ERROR_SUCCESS) {
+    // This will occur on first-run, but is harmless.
+    return;
+  }
+
+  base::win::RegistryKeyIterator iterator_test_root_key(HKEY_CURRENT_USER,
+                                                        test_key_root.c_str());
+  for (; iterator_test_root_key.Valid(); ++iterator_test_root_key) {
+    string16 key_name = iterator_test_root_key.Name();
+    std::vector<string16> tokens;
+    Tokenize(key_name, string16(kTimestampDelimiter), &tokens);
+    int64 key_name_as_number = 0;
+
+    if (!base::StringToInt64(tokens[0], &key_name_as_number)) {
+      test_root_key.DeleteKey(key_name.c_str());
+      continue;
+    }
+
+    base::Time key_time = base::Time::FromInternalValue(key_name_as_number);
+    base::TimeDelta age = now - key_time;
+
+    if (age > base::TimeDelta::FromHours(24))
+      test_root_key.DeleteKey(key_name.c_str());
+  }
+}
+
+string16 GenerateTempKeyPath(const string16& test_key_root,
+                             const base::Time& timestamp) {
+  string16 key_path = test_key_root;
+  key_path += L"\\" + base::Int64ToString16(timestamp.ToInternalValue());
+  key_path += kTimestampDelimiter + base::ASCIIToWide(base::GenerateGUID());
+
+  return key_path;
+}
+
+}  // namespace
 
 RegistryOverrideManager::ScopedRegistryKeyOverride::ScopedRegistryKeyOverride(
     HKEY override,
-    const std::wstring& temp_name)
-    : override_(override),
-      temp_name_(temp_name) {
-  DCHECK(!temp_name_.empty());
-  std::wstring key_path(RegistryOverrideManager::kTempTestKeyPath);
-  key_path += L"\\" + temp_name_;
-  EXPECT_EQ(ERROR_SUCCESS,
+    const string16& key_path)
+    : override_(override) {
+  EXPECT_EQ(
+      ERROR_SUCCESS,
       temp_key_.Create(HKEY_CURRENT_USER, key_path.c_str(), KEY_ALL_ACCESS));
   EXPECT_EQ(ERROR_SUCCESS,
             ::RegOverridePredefKey(override_, temp_key_.Handle()));
 }
 
 RegistryOverrideManager::
     ScopedRegistryKeyOverride::~ScopedRegistryKeyOverride() {
   ::RegOverridePredefKey(override_, NULL);
-  // The temp key will be deleted via a call to DeleteAllTempKeys().
+  temp_key_.DeleteKey(L"");
 }
 
-RegistryOverrideManager::RegistryOverrideManager() {
-  DeleteAllTempKeys();
+RegistryOverrideManager::RegistryOverrideManager()
+    : timestamp_(base::Time::Now()), test_key_root_(kTempTestKeyPath) {
+  DeleteStaleTestKeys(timestamp_, test_key_root_);
 }
 
-RegistryOverrideManager::~RegistryOverrideManager() {
-  RemoveAllOverrides();
+RegistryOverrideManager::RegistryOverrideManager(const base::Time& timestamp,
+                                                 const string16& test_key_root)
+    : timestamp_(timestamp), test_key_root_(test_key_root) {
+  DeleteStaleTestKeys(timestamp_, test_key_root_);
 }
 
+RegistryOverrideManager::~RegistryOverrideManager() {}
+
 void RegistryOverrideManager::OverrideRegistry(HKEY override,
-                                               const std::wstring& temp_name) {
-  overrides_.push_back(new ScopedRegistryKeyOverride(override, temp_name));
+                                               const string16& override_name) {
+  string16 key_path = GenerateTempKeyPath(test_key_root_, timestamp_);
+  overrides_.push_back(new ScopedRegistryKeyOverride(override, key_path));
 }
 
-void RegistryOverrideManager::RemoveAllOverrides() {
-  while (!overrides_.empty()) {
-    delete overrides_.back();
-    overrides_.pop_back();
-  }
-
-  DeleteAllTempKeys();
-}
-
-// static
-void RegistryOverrideManager::DeleteAllTempKeys() {
-  base::win::RegKey key;
-  if (key.Open(HKEY_CURRENT_USER, L"", KEY_ALL_ACCESS) == ERROR_SUCCESS) {
-    key.DeleteKey(kTempTestKeyPath);
-  }
+string16 GenerateTempKeyPath() {
+  return GenerateTempKeyPath(string16(kTempTestKeyPath), base::Time::Now());
 }
 
 }  // namespace registry_util