Refactor PrefHashStore's BeginTransaction to take a rawptr

components/user_prefs/tracked/pref_hash_store_impl_unittest.cc

 // Copyright 2013 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 "components/user_prefs/tracked/pref_hash_store_impl.h"
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/values.h"
 #include "components/user_prefs/tracked/dictionary_hash_store_contents.h"
 #include "components/user_prefs/tracked/hash_store_contents.h"
 #include "components/user_prefs/tracked/pref_hash_store_impl.h"
 #include "components/user_prefs/tracked/pref_hash_store_transaction.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 class PrefHashStoreImplTest : public testing::Test {
- protected:
-  std::unique_ptr<HashStoreContents> CreateHashStoreContents() {
-    return std::unique_ptr<HashStoreContents>(
-        new DictionaryHashStoreContents(&pref_store_contents_));
+ public:
+  void SetUp() override {
+    contents_.reset(new DictionaryHashStoreContents(&pref_store_contents_));

[gab, 2016/09/01 20:31:50]

A chromium-dev discussion just concluded in favor of avoiding naked "new" and
using MakeUnique as much as possible instead :
https://groups.google.com/a/chromium.org/d/topic/chromium-dev/iQgMedVA8-k/dis...

But here, even better, initialization can be done in the constructor's
initializer list and this doesn't even need to be in a unique_ptr:

PrefHashStoreImplTest() 
    : contents_(&pref_store_contents_) {}

[proberge, 2016/09/06 19:24:10]

Done.

   }
 
+ protected:
+  HashStoreContents* GetHashStoreContents() { return contents_.get(); }
+
  private:
+  std::unique_ptr<HashStoreContents> contents_;

[gab, 2016/09/01 20:31:50]

Needs to be after |pref_store_contents_| as members are initialized in order and
destroyed in reverse order (and this one depends on |pref_store_contents_|).

Move it and add a comment like:

// Must be declared after |pref_store_contents_| as it needs to be outlived by
it.

[proberge, 2016/09/06 19:24:10]

Done.

   base::DictionaryValue pref_store_contents_;
 };

[gab, 2016/09/01 20:31:50]

DISALLOW_COPY_AND_ASSIGN(PrefHashStoreImplTest);

(this was written in days where Chromium was sloppy about
DISALLOW_COPY_AND_ASSIGN in test fixtures but we long ago decided to enforce it
everywhere, so cleaning it up here would be nice :-))

[proberge, 2016/09/06 19:24:10]

Done.

 
 TEST_F(PrefHashStoreImplTest, AtomicHashStoreAndCheck) {
   base::StringValue string_1("string1");
   base::StringValue string_2("string2");
 
   {
     // 32 NULL bytes is the seed that was used to generate the legacy hash.
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
 
     // Only NULL should be trusted in the absence of a hash.
     EXPECT_EQ(PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("path1", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_NULL_VALUE,
               transaction->CheckValue("path1", NULL));
 
     transaction->StoreHash("path1", &string_1);
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::CLEARED,
               transaction->CheckValue("path1", NULL));
     transaction->StoreHash("path1", NULL);
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", NULL));
     EXPECT_EQ(PrefHashStoreTransaction::CHANGED,
               transaction->CheckValue("path1", &string_2));
 
     base::DictionaryValue dict;
     dict.Set("a", new base::StringValue("foo"));
     dict.Set("d", new base::StringValue("bad"));
     dict.Set("b", new base::StringValue("bar"));
     dict.Set("c", new base::StringValue("baz"));
 
     transaction->StoreHash("path1", &dict);
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &dict));
   }
 
-  ASSERT_FALSE(CreateHashStoreContents()->GetSuperMac().empty());
+  ASSERT_FALSE(GetHashStoreContents()->GetSuperMac().empty());
 
   {
     // |pref_hash_store2| should trust its initial hashes dictionary and thus
     // trust new unknown values.
     PrefHashStoreImpl pref_hash_store2(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store2.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store2.BeginTransaction(GetHashStoreContents()));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("new_path", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("new_path", &string_2));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_NULL_VALUE,
               transaction->CheckValue("new_path", NULL));
   }
 
   // Manually corrupt the super MAC.
-  CreateHashStoreContents()->SetSuperMac(std::string(64, 'A'));
+  GetHashStoreContents()->SetSuperMac(std::string(64, 'A'));
 
   {
     // |pref_hash_store3| should no longer trust its initial hashes dictionary
     // and thus shouldn't trust non-NULL unknown values.
     PrefHashStoreImpl pref_hash_store3(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store3.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store3.BeginTransaction(GetHashStoreContents()));
     EXPECT_EQ(PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("new_path", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("new_path", &string_2));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_NULL_VALUE,
               transaction->CheckValue("new_path", NULL));
   }
 }
 
 TEST_F(PrefHashStoreImplTest, ImportExportOperations) {
   base::StringValue string_1("string1");
   base::StringValue string_2("string2");
 
   // Initial state: no super MAC.
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_FALSE(transaction->IsSuperMACValid());
 
     ASSERT_FALSE(transaction->HasHash("path1"));
 
     // Storing a hash will stamp the super MAC.
     transaction->StoreHash("path1", &string_1);
 
     ASSERT_TRUE(transaction->HasHash("path1"));
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::CHANGED,
               transaction->CheckValue("path1", &string_2));
   }
 
   // Make a copy of the stored hash for future use.
   const base::Value* hash = NULL;
-  ASSERT_TRUE(CreateHashStoreContents()->GetContents()->Get("path1", &hash));
+  ASSERT_TRUE(GetHashStoreContents()->GetContents()->Get("path1", &hash));
   std::unique_ptr<base::Value> path_1_string_1_hash_copy(hash->DeepCopy());
   hash = NULL;
 
   // Verify that the super MAC was stamped.
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_TRUE(transaction->IsSuperMACValid());
     ASSERT_TRUE(transaction->HasHash("path1"));
 
     // Clearing the hash should preserve validity.
     transaction->ClearHash("path1");
 
     // The effects of the clear should be immediately visible.
     ASSERT_FALSE(transaction->HasHash("path1"));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_NULL_VALUE,
               transaction->CheckValue("path1", NULL));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("path1", &string_1));
   }
 
   // Verify that validity was preserved and that the clear took effect.
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_TRUE(transaction->IsSuperMACValid());
     ASSERT_FALSE(transaction->HasHash("path1"));
   }
 
   // Invalidate the super MAC.
-  CreateHashStoreContents()->SetSuperMac(std::string());
+  GetHashStoreContents()->SetSuperMac(std::string());
 
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_FALSE(transaction->IsSuperMACValid());
     ASSERT_FALSE(transaction->HasHash("path1"));
 
     // An import should preserve invalidity.
     transaction->ImportHash("path1", path_1_string_1_hash_copy.get());
 
     ASSERT_TRUE(transaction->HasHash("path1"));
 
     // The imported hash should be usable for validating the original value.
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_1));
   }
 
   // Verify that invalidity was preserved and that the import took effect.
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_FALSE(transaction->IsSuperMACValid());
     ASSERT_TRUE(transaction->HasHash("path1"));
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_1));
 
     // After clearing the hash, non-null values are UNTRUSTED_UNKNOWN.
     transaction->ClearHash("path1");
 
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_NULL_VALUE,
               transaction->CheckValue("path1", NULL));
     EXPECT_EQ(PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("path1", &string_1));
   }
 
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_FALSE(transaction->IsSuperMACValid());
 
     // Test StampSuperMac.
     transaction->StampSuperMac();
   }
 
   // Verify that the store is now valid.
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_TRUE(transaction->IsSuperMACValid());
 
     // Store the hash of a different value to test an "over-import".
     transaction->StoreHash("path1", &string_2);
     EXPECT_EQ(PrefHashStoreTransaction::CHANGED,
               transaction->CheckValue("path1", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_2));
   }
 
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_TRUE(transaction->IsSuperMACValid());
 
     // "Over-import". An import should preserve validity.
     transaction->ImportHash("path1", path_1_string_1_hash_copy.get());
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::CHANGED,
               transaction->CheckValue("path1", &string_2));
   }
 
   // Verify that validity was preserved and the "over-import" took effect.
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
     ASSERT_TRUE(transaction->IsSuperMACValid());
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_1));
     EXPECT_EQ(PrefHashStoreTransaction::CHANGED,
               transaction->CheckValue("path1", &string_2));
   }
 }
 
 TEST_F(PrefHashStoreImplTest, SuperMACDisabled) {
   base::StringValue string_1("string1");
   base::StringValue string_2("string2");
 
   {
     // Pass |use_super_mac| => false.
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", false);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
 
     transaction->StoreHash("path1", &string_2);
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string_2));
   }
 
-  ASSERT_TRUE(CreateHashStoreContents()->GetSuperMac().empty());
+  ASSERT_TRUE(GetHashStoreContents()->GetSuperMac().empty());
 
   {
     PrefHashStoreImpl pref_hash_store2(std::string(32, 0), "device_id", false);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store2.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store2.BeginTransaction(GetHashStoreContents()));
     EXPECT_EQ(PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE,
               transaction->CheckValue("new_path", &string_1));
   }
 }
 
 TEST_F(PrefHashStoreImplTest, SplitHashStoreAndCheck) {
   base::DictionaryValue dict;
   dict.Set("a", new base::StringValue("to be replaced"));
   dict.Set("b", new base::StringValue("same"));
   dict.Set("o", new base::StringValue("old"));
 
   base::DictionaryValue modified_dict;
   modified_dict.Set("a", new base::StringValue("replaced"));
   modified_dict.Set("b", new base::StringValue("same"));
   modified_dict.Set("c", new base::StringValue("new"));
 
   base::DictionaryValue empty_dict;
 
   std::vector<std::string> invalid_keys;
 
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
 
     // No hashes stored yet and hashes dictionary is empty (and thus not
     // trusted).
     EXPECT_EQ(PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE,
               transaction->CheckSplitValue("path1", &dict, &invalid_keys));
     EXPECT_TRUE(invalid_keys.empty());
 
     transaction->StoreSplitHash("path1", &dict);
 
     // Verify match post storage.
@@ skipping 49 matching lines @@
     expected_invalid_keys2.push_back("c");
     EXPECT_EQ(expected_invalid_keys2, invalid_keys);
     invalid_keys.clear();
   }
 
   {
     // |pref_hash_store2| should trust its initial hashes dictionary and thus
     // trust new unknown values.
     PrefHashStoreImpl pref_hash_store2(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store2.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store2.BeginTransaction(GetHashStoreContents()));
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE,
               transaction->CheckSplitValue("new_path", &dict, &invalid_keys));
     EXPECT_TRUE(invalid_keys.empty());
   }
 
   // Manually corrupt the super MAC.
-  CreateHashStoreContents()->SetSuperMac(std::string(64, 'A'));
+  GetHashStoreContents()->SetSuperMac(std::string(64, 'A'));
 
   {
     // |pref_hash_store3| should no longer trust its initial hashes dictionary
     // and thus shouldn't trust unknown values.
     PrefHashStoreImpl pref_hash_store3(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store3.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store3.BeginTransaction(GetHashStoreContents()));
     EXPECT_EQ(PrefHashStoreTransaction::UNTRUSTED_UNKNOWN_VALUE,
               transaction->CheckSplitValue("new_path", &dict, &invalid_keys));
     EXPECT_TRUE(invalid_keys.empty());
   }
 }
 
 TEST_F(PrefHashStoreImplTest, EmptyAndNULLSplitDict) {
   base::DictionaryValue empty_dict;
 
   std::vector<std::string> invalid_keys;
 
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
 
     // Store hashes for a random dict to be overwritten below.
     base::DictionaryValue initial_dict;
     initial_dict.Set("a", new base::StringValue("foo"));
     transaction->StoreSplitHash("path1", &initial_dict);
 
     // Verify stored empty dictionary matches NULL and empty dictionary back.
     transaction->StoreSplitHash("path1", &empty_dict);
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckSplitValue("path1", NULL, &invalid_keys));
@@ skipping 15 matching lines @@
   }
 
   {
     // |pref_hash_store2| should trust its initial hashes dictionary (and thus
     // trust new unknown values) even though the last action done was to clear
     // the hashes for path1 by setting its value to NULL (this is a regression
     // test ensuring that the internal action of clearing some hashes does
     // update the stored hash of hashes).
     PrefHashStoreImpl pref_hash_store2(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store2.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store2.BeginTransaction(GetHashStoreContents()));
 
     base::DictionaryValue tested_dict;
     tested_dict.Set("a", new base::StringValue("foo"));
     tested_dict.Set("b", new base::StringValue("bar"));
     EXPECT_EQ(
         PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE,
         transaction->CheckSplitValue("new_path", &tested_dict, &invalid_keys));
     EXPECT_TRUE(invalid_keys.empty());
   }
 }
 
 // Test that the PrefHashStore returns TRUSTED_UNKNOWN_VALUE when checking for
 // a split preference even if there is an existing atomic preference's hash
 // stored. There is no point providing a migration path for preferences
 // switching strategies after their initial release as split preferences are
 // turned into split preferences specifically because the atomic hash isn't
 // considered useful.
 TEST_F(PrefHashStoreImplTest, TrustedUnknownSplitValueFromExistingAtomic) {
   base::StringValue string("string1");
 
   base::DictionaryValue dict;
   dict.Set("a", new base::StringValue("foo"));
   dict.Set("d", new base::StringValue("bad"));
   dict.Set("b", new base::StringValue("bar"));
   dict.Set("c", new base::StringValue("baz"));
 
   {
     PrefHashStoreImpl pref_hash_store(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store.BeginTransaction(GetHashStoreContents()));
 
     transaction->StoreHash("path1", &string);
     EXPECT_EQ(PrefHashStoreTransaction::UNCHANGED,
               transaction->CheckValue("path1", &string));
   }
 
   {
     // Load a new |pref_hash_store2| in which the hashes dictionary is trusted.
     PrefHashStoreImpl pref_hash_store2(std::string(32, 0), "device_id", true);
     std::unique_ptr<PrefHashStoreTransaction> transaction(
-        pref_hash_store2.BeginTransaction(CreateHashStoreContents()));
+        pref_hash_store2.BeginTransaction(GetHashStoreContents()));
     std::vector<std::string> invalid_keys;
     EXPECT_EQ(PrefHashStoreTransaction::TRUSTED_UNKNOWN_VALUE,
               transaction->CheckSplitValue("path1", &dict, &invalid_keys));
     EXPECT_TRUE(invalid_keys.empty());
   }
 }