Make a JsonPrefStore readable while mid-interception.

base/prefs/json_pref_store_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/prefs/json_pref_store.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/ref_counted.h"
@@ skipping 19 matching lines @@
 // A PrefFilter that will intercept all calls to FilterOnLoad() and hold on
 // to the |prefs| until explicitly asked to release them.
 class InterceptingPrefFilter : public PrefFilter {
  public:
   InterceptingPrefFilter();
   virtual ~InterceptingPrefFilter();
 
   // PrefFilter implementation:
   virtual void FilterOnLoad(
       const PostFilterOnLoadCallback& post_filter_on_load_callback,
-      scoped_ptr<base::DictionaryValue> pref_store_contents) OVERRIDE;
+      base::DictionaryValue* pref_store_contents) OVERRIDE;
   virtual void FilterUpdate(const std::string& path) OVERRIDE {}
   virtual void FilterSerializeData(
       const base::DictionaryValue* pref_store_contents) OVERRIDE {}
 
   bool has_intercepted_prefs() const { return intercepted_prefs_ != NULL; }
 
   // Finalize an intercepted read, handing |intercept_prefs_| back to its
   // JsonPrefStore.
   void ReleasePrefs();
 
  private:
   PostFilterOnLoadCallback post_filter_on_load_callback_;
-  scoped_ptr<base::DictionaryValue> intercepted_prefs_;
+  base::DictionaryValue* intercepted_prefs_;
 
   DISALLOW_COPY_AND_ASSIGN(InterceptingPrefFilter);
 };
 
-InterceptingPrefFilter::InterceptingPrefFilter() {}
+InterceptingPrefFilter::InterceptingPrefFilter() : intercepted_prefs_(NULL) {}
 InterceptingPrefFilter::~InterceptingPrefFilter() {}
 
 void InterceptingPrefFilter::FilterOnLoad(
     const PostFilterOnLoadCallback& post_filter_on_load_callback,
-    scoped_ptr<base::DictionaryValue> pref_store_contents) {
+    base::DictionaryValue* pref_store_contents) {
   post_filter_on_load_callback_ = post_filter_on_load_callback;
-  intercepted_prefs_ = pref_store_contents.Pass();
+  intercepted_prefs_ = pref_store_contents;
 }
 
 void InterceptingPrefFilter::ReleasePrefs() {

[gab, 2014/06/11 21:12:55]

"ReleasePrefs" is technically wrong now that this object is no longer holding on
to prefs..

   EXPECT_FALSE(post_filter_on_load_callback_.is_null());
-  post_filter_on_load_callback_.Run(intercepted_prefs_.Pass(), false);
+  intercepted_prefs_ = NULL;
+  post_filter_on_load_callback_.Run(false);
   post_filter_on_load_callback_.Reset();
 }
 
 class MockPrefStoreObserver : public PrefStore::Observer {
  public:
   MOCK_METHOD1(OnPrefValueChanged, void (const std::string&));
   MOCK_METHOD1(OnInitializationCompleted, void (bool));
 };
 
 class MockReadErrorDelegate : public PersistentPrefStore::ReadErrorDelegate {
@@ skipping 293 matching lines @@
                         intercepting_pref_filter.PassAs<PrefFilter>());
 
   ASSERT_EQ(PersistentPrefStore::PREF_READ_ERROR_ASYNCHRONOUS_TASK_INCOMPLETE,
             pref_store->ReadPrefs());
   EXPECT_FALSE(pref_store->ReadOnly());
 
   // The store shouldn't be considered initialized until the interceptor
   // returns.
   EXPECT_TRUE(raw_intercepting_pref_filter_->has_intercepted_prefs());
   EXPECT_FALSE(pref_store->IsInitializationComplete());
-  EXPECT_FALSE(pref_store->GetValue(kHomePage, NULL));
+
+  // The store should be readable while mid-interception.
+  EXPECT_TRUE(pref_store->GetValue(kHomePage, NULL));
 
   raw_intercepting_pref_filter_->ReleasePrefs();
 
   EXPECT_FALSE(raw_intercepting_pref_filter_->has_intercepted_prefs());
   EXPECT_TRUE(pref_store->IsInitializationComplete());
   EXPECT_TRUE(pref_store->GetValue(kHomePage, NULL));
 
   // The JSON file looks like this:
   // {
   //   "homepage": "http://www.cnn.com",
@@ skipping 35 matching lines @@
     pref_store->ReadPrefsAsync(mock_error_delegate);
 
     EXPECT_CALL(mock_observer, OnInitializationCompleted(true)).Times(0);
     // EXPECT_CALL(*mock_error_delegate,
     //             OnError(PersistentPrefStore::PREF_READ_ERROR_NONE)).Times(0);
     RunLoop().RunUntilIdle();
 
     EXPECT_FALSE(pref_store->ReadOnly());
     EXPECT_TRUE(raw_intercepting_pref_filter_->has_intercepted_prefs());
     EXPECT_FALSE(pref_store->IsInitializationComplete());
-    EXPECT_FALSE(pref_store->GetValue(kHomePage, NULL));
+    EXPECT_TRUE(pref_store->GetValue(kHomePage, NULL));
   }
 
   {
     EXPECT_CALL(mock_observer, OnInitializationCompleted(true)).Times(1);
     // EXPECT_CALL(*mock_error_delegate,
     //             OnError(PersistentPrefStore::PREF_READ_ERROR_NONE)).Times(0);
 
     raw_intercepting_pref_filter_->ReleasePrefs();
 
     EXPECT_FALSE(pref_store->ReadOnly());
@@ skipping 12 matching lines @@
   //     "new_windows_in_tabs": true,
   //     "max_tabs": 20
   //   }
   // }
 
   RunBasicJsonPrefStoreTest(
       pref_store.get(), input_file, data_dir_.AppendASCII("write.golden.json"));
 }
 
 }  // namespace base