[GRC] Coordination Unit Graph Observer

services/resource_coordinator/coordination_unit/coordination_unit_impl.h

 // Copyright 2017 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.
 
 #ifndef SERVICES_RESOURCE_COORDINATOR_COORDINATION_UNIT_COORDINATION_UNIT_IMPL_H_
 #define SERVICES_RESOURCE_COORDINATOR_COORDINATION_UNIT_COORDINATION_UNIT_IMPL_H_
 
 #include <list>
 #include <map>
 #include <memory>
 #include <set>
 #include <unordered_map>
 #include <utility>
 #include <vector>
 
 #include "base/callback.h"
+#include "base/observer_list.h"
 #include "base/optional.h"
 #include "base/values.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "mojo/public/cpp/bindings/interface_request.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 #include "services/resource_coordinator/public/cpp/coordination_unit_id.h"
 #include "services/resource_coordinator/public/cpp/coordination_unit_types.h"
 #include "services/resource_coordinator/public/interfaces/coordination_unit.mojom.h"
 #include "services/resource_coordinator/public/interfaces/coordination_unit_provider.mojom.h"
 #include "services/service_manager/public/cpp/service_context_ref.h"
 
 namespace resource_coordinator {
 
 class CoordinationUnitGraphObserver;
 
-// Collection to manage CoordinationUnitEvent listeners.
-template <typename Filter>
-class CoordinationUnitGraphObserverRegistry {
- public:
-  CoordinationUnitGraphObserverRegistry() = default;
-  ~CoordinationUnitGraphObserverRegistry() = default;
-
-  // callbacks paired with this kNoFilter will always be invoked
-  static const Filter kNoFilter = static_cast<Filter>(0);
-
-  void AddObserver(CoordinationUnitGraphObserver* observer, Filter filter) {
-    registry_[filter].push_back(observer);
-  }
-
-  void AddObserver(CoordinationUnitGraphObserver* observer) {
-    AddObserver(observer, kNoFilter);
-  }
-
-  // Get the observers who are are either registered to be invoked for
-  // a specific filter or were registered with the kNoFilter.
-  // TODO(matthalp) add iterator support to replace this call and
-  // avoid excessive copying that currently occurs
-  std::vector<CoordinationUnitGraphObserver*> GetObserversForFilter(
-      Filter filter) {
-    std::vector<CoordinationUnitGraphObserver*> observers;
-
-    // Get listeners registered with a listener first.
-    AppendObservers(&observers, filter);
-
-    // Get listeners registered without a filter after.
-    if (filter != kNoFilter) {
-      AppendObservers(&observers, kNoFilter);
-    }
-
-    return observers;
-  }
-
-  std::vector<CoordinationUnitGraphObserver*> GetObserversWithoutAFilter() {
-    return GetObserversForFilter(kNoFilter);
-  }
-
- private:
-  void AppendObservers(std::vector<CoordinationUnitGraphObserver*>* observers,
-                       Filter filter) {
-    observers->insert(observers->end(), registry_[filter].begin(),
-                      registry_[filter].end());
-  }
-
-  // TODO(matthalp) Consider using a std::unordered_map instead.
-  std::map<Filter, std::vector<CoordinationUnitGraphObserver*>> registry_;
-
-  DISALLOW_COPY_AND_ASSIGN(CoordinationUnitGraphObserverRegistry);
-};
-
 class CoordinationUnitImpl : public mojom::CoordinationUnit {
  public:
   CoordinationUnitImpl(
       const CoordinationUnitID& id,
       std::unique_ptr<service_manager::ServiceContextRef> service_ref);
   ~CoordinationUnitImpl() override;
 
   // Overridden from mojom::CoordinationUnit:
   void SendEvent(mojom::EventPtr event) override;
   void GetID(const GetIDCallback& callback) override;
@@ skipping 16 matching lines @@
   static const double kCPUUsageUnmeasuredForTesting;
   virtual double GetCPUUsageForTesting();
 
   // Clear property from internal key-value store
   void ClearProperty(mojom::PropertyType property);
   // Retrieve property from internal key-value store
   base::Value GetProperty(mojom::PropertyType property) const;
   // Set property from internal key-value store
   void SetProperty(mojom::PropertyType property, base::Value value);
 
-  // Notify an instance it will be destroyed before its destructor is
-  // actually called.
-  void WillBeDestroyed();
-
-  void ObserveOnChildAddedEvent(CoordinationUnitGraphObserver* observer,
-                                CoordinationUnitType child_filter);
-  void ObserveOnChildAddedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnParentAddedEvent(CoordinationUnitGraphObserver* observer,
-                                 CoordinationUnitType parent_filter);
-  void ObserveOnParentAddedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnPropertyChangedEvent(CoordinationUnitGraphObserver* observer,
-                                     mojom::PropertyType property_filter);
-  void ObserveOnPropertyChangedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnChildRemovedEvent(CoordinationUnitGraphObserver* observer,
-                                  CoordinationUnitType child_filter);
-  void ObserveOnChildRemovedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnParentRemovedEvent(CoordinationUnitGraphObserver* observer,
-                                   CoordinationUnitType parent_filter);
-  void ObserveOnParentRemovedEvent(CoordinationUnitGraphObserver* observer);
-  void ObserveOnWillBeDestroyedEvent(CoordinationUnitGraphObserver* observer);
+  void AddObserver(CoordinationUnitGraphObserver* observer);
+  void RemoveObserver(CoordinationUnitGraphObserver* observer);
 
  protected:
   const CoordinationUnitID id_;
   std::set<CoordinationUnitImpl*> children_;
   std::set<CoordinationUnitImpl*> parents_;
 
  private:
   bool AddChild(CoordinationUnitImpl* child);
   bool RemoveChild(CoordinationUnitImpl* child);
   void AddParent(CoordinationUnitImpl* parent);
@@ skipping 14 matching lines @@
     kNumStateFlags
   };
   bool SelfOrParentHasFlagSet(StateFlags state);
 
   std::unique_ptr<service_manager::ServiceContextRef> service_ref_;
   mojo::BindingSet<mojom::CoordinationUnit> bindings_;
 
   mojom::CoordinationPolicyCallbackPtr policy_callback_;
   mojom::CoordinationPolicyPtr current_policy_;
 
+  base::ObserverList<CoordinationUnitGraphObserver> observers_;
+
   base::Optional<bool> state_flags_[kNumStateFlags];
 
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_child_added_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_parent_added_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_child_removed_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_parent_removed_event_observer_registry_;
-  CoordinationUnitGraphObserverRegistry<mojom::PropertyType>
-      on_property_changed_event_observer_registry_;
-  // There is nothing to filter WillBeDestroyedEventCallbacks on so the
-  // CoordinationUnitType is used as a filter placeholder
-  CoordinationUnitGraphObserverRegistry<CoordinationUnitType>
-      on_will_be_destroyed_event_observer_registry_;
-
   DISALLOW_COPY_AND_ASSIGN(CoordinationUnitImpl);
 };
 
 }  // namespace resource_coordinator
 
 #endif  // SERVICES_RESOURCE_COORDINATOR_COORDINATION_UNIT_COORDINATION_UNIT_IMPL_H_