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      1 // Copyright 2014 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_DEPENDENCY_MANAGER_H_
      6 #define COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_DEPENDENCY_MANAGER_H_
      7 
      8 #include "base/callback_forward.h"
      9 #include "base/callback_list.h"
     10 #include "base/memory/singleton.h"
     11 #include "components/keyed_service/core/dependency_graph.h"
     12 #include "components/keyed_service/core/keyed_service_export.h"
     13 
     14 #ifndef NDEBUG
     15 #include <set>
     16 #endif
     17 
     18 class BrowserContextKeyedBaseFactory;
     19 
     20 namespace content {
     21 class BrowserContext;
     22 }
     23 
     24 namespace user_prefs {
     25 class PrefRegistrySyncable;
     26 }
     27 
     28 // A singleton that listens for context destruction notifications and
     29 // rebroadcasts them to each BrowserContextKeyedBaseFactory in a safe order
     30 // based on the stated dependencies by each service.
     31 class KEYED_SERVICE_EXPORT BrowserContextDependencyManager {
     32  public:
     33   // Adds/Removes a component from our list of live components. Removing will
     34   // also remove live dependency links.
     35   void AddComponent(BrowserContextKeyedBaseFactory* component);
     36   void RemoveComponent(BrowserContextKeyedBaseFactory* component);
     37 
     38   // Adds a dependency between two factories.
     39   void AddEdge(BrowserContextKeyedBaseFactory* depended,
     40                BrowserContextKeyedBaseFactory* dependee);
     41 
     42   // Registers profile-specific preferences for all services via |registry|.
     43   // |context| should be the BrowserContext containing |registry| and is used as
     44   // a key to prevent multiple registrations on the same BrowserContext in
     45   // tests.
     46   void RegisterProfilePrefsForServices(
     47       const content::BrowserContext* context,
     48       user_prefs::PrefRegistrySyncable* registry);
     49 
     50   // Called by each BrowserContext to alert us of its creation. Several
     51   // services want to be started when a context is created. If you want your
     52   // KeyedService to be started with the BrowserContext, override
     53   // BrowserContextKeyedBaseFactory::ServiceIsCreatedWithBrowserContext() to
     54   // return true. This method also registers any service-related preferences
     55   // for non-incognito profiles.
     56   void CreateBrowserContextServices(content::BrowserContext* context);
     57 
     58   // Similar to CreateBrowserContextServices(), except this is used for creating
     59   // test BrowserContexts - these contexts will not create services for any
     60   // BrowserContextKeyedBaseFactories that return true from
     61   // ServiceIsNULLWhileTesting().
     62   void CreateBrowserContextServicesForTest(content::BrowserContext* context);
     63 
     64   // Called by each BrowserContext to alert us that we should destroy services
     65   // associated with it.
     66   void DestroyBrowserContextServices(content::BrowserContext* context);
     67 
     68   // Registers a |callback| that will be called just before executing
     69   // CreateBrowserContextServices() or CreateBrowserContextServicesForTest().
     70   // This can be useful in browser tests which wish to substitute test or mock
     71   // builders for the keyed services.
     72   scoped_ptr<base::CallbackList<void(content::BrowserContext*)>::Subscription>
     73   RegisterWillCreateBrowserContextServicesCallbackForTesting(
     74       const base::Callback<void(content::BrowserContext*)>& callback);
     75 
     76 #ifndef NDEBUG
     77   // Debugging assertion called as part of GetServiceForBrowserContext in debug
     78   // mode. This will NOTREACHED() whenever the user is trying to access a stale
     79   // BrowserContext*.
     80   void AssertBrowserContextWasntDestroyed(content::BrowserContext* context);
     81 
     82   // Marks |context| as live (i.e., not stale). This method can be called as a
     83   // safeguard against |AssertBrowserContextWasntDestroyed()| checks going off
     84   // due to |context| aliasing a BrowserContext instance from a prior test
     85   // (i.e., 0xWhatever might be created, be destroyed, and then a new
     86   // BrowserContext object might be created at 0xWhatever).
     87   void MarkBrowserContextLiveForTesting(content::BrowserContext* context);
     88 #endif
     89 
     90   static BrowserContextDependencyManager* GetInstance();
     91 
     92  private:
     93   friend class BrowserContextDependencyManagerUnittests;
     94   friend struct DefaultSingletonTraits<BrowserContextDependencyManager>;
     95 
     96   // Helper function used by CreateBrowserContextServices[ForTest].
     97   void DoCreateBrowserContextServices(content::BrowserContext* context,
     98                                       bool is_testing_context);
     99 
    100   BrowserContextDependencyManager();
    101   virtual ~BrowserContextDependencyManager();
    102 
    103 #ifndef NDEBUG
    104   void DumpBrowserContextDependencies(content::BrowserContext* context);
    105 #endif
    106 
    107   DependencyGraph dependency_graph_;
    108 
    109   // A list of callbacks to call just before executing
    110   // CreateBrowserContextServices() or CreateBrowserContextServicesForTest().
    111   base::CallbackList<void(content::BrowserContext*)>
    112       will_create_browser_context_services_callbacks_;
    113 
    114 #ifndef NDEBUG
    115   // A list of context objects that have gone through the Shutdown()
    116   // phase. These pointers are most likely invalid, but we keep track of their
    117   // locations in memory so we can nicely assert if we're asked to do anything
    118   // with them.
    119   std::set<content::BrowserContext*> dead_context_pointers_;
    120 #endif
    121 };
    122 
    123 #endif  // COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_DEPENDENCY_MANAGER_H_
    124