Implement an observer for the component updater.

chrome/browser/component_updater/component_updater_service.h

 // Copyright 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.
 
 #ifndef CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_
 #define CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 40 matching lines @@
   // Set |installed_file| to the full path to the installed |file|. |file| is
   // the filename of the file in this component's CRX. Returns false if this is
   // not possible (the file has been removed or modified, or its current
   // location is unknown). Otherwise, returns true.
   virtual bool GetInstalledFile(const std::string& file,
                                 base::FilePath* installed_file) = 0;
 
   virtual ~ComponentInstaller() {}
 };
 
-// Defines an interface to observe a CrxComponent.
-class ComponentObserver {
- public:
-  enum Events {
-    // Sent when the component updater starts doing update checks.
-    COMPONENT_UPDATER_STARTED,
-
-    // Sent when the component updater is going to take a long nap.
-    COMPONENT_UPDATER_SLEEPING,
-
-    // Sent when there is a new version of a registered component. After
-    // the notification is sent the component will be downloaded.
-    COMPONENT_UPDATE_FOUND,
-
-    // Sent when the new component has been downloaded and an installation
-    // or upgrade is about to be attempted.
-    COMPONENT_UPDATE_READY,
-
-    // Sent when a component has been successfully updated.
-    COMPONENT_UPDATED,
-
-    // Sent when a component has not been updated following an update check:
-    // either there was no update available, or an update failed.
-    COMPONENT_NOT_UPDATED,
-  };
-
-  virtual ~ComponentObserver() {}
-
-  // The component updater service will call this function when an interesting
-  // event happens for a specific component. |extra| is |event| dependent.
-  virtual void OnEvent(Events event, int extra) = 0;
-};
-
 // Describes a particular component that can be installed or updated. This
 // structure is required to register a component with the component updater.
 // |pk_hash| is the SHA256 hash of the component's public key. If the component
 // is to be installed then version should be "0" or "0.0", else it should be
-// the current version. |observer|, |fingerprint|, and |name| are optional.
+// the current version. |fingerprint|, and |name| are optional.
 // |allow_background_download| specifies that the component can be background
 // downloaded in some cases. The default for this value is |true| and the value
 // can be overriden at the registration time. This is a temporary change until
 // the issue 340448 is resolved.
 struct CrxComponent {
   std::vector<uint8> pk_hash;
   ComponentInstaller* installer;
-  ComponentObserver* observer;
   Version version;
   std::string fingerprint;
   std::string name;
   bool allow_background_download;
   CrxComponent();
   ~CrxComponent();
 };
 
 // Convenience structure to use with component listing / enumeration.
 struct CrxComponentInfo {
@@ skipping 60 matching lines @@
     virtual net::URLRequestContextGetter* RequestContext() = 0;
     // True means that all ops are performed in this process.
     virtual bool InProcess() = 0;
     // True means that this client can handle delta updates.
     virtual bool DeltasEnabled() const = 0;
     // True means that the background downloader can be used for downloading
     // non on-demand components.
     virtual bool UseBackgroundDownloader() const = 0;
   };
 
+  // Defines an interface to observe ComponentUpdateService. It provides
+  // notifications when state changes occur for the service or for the
+  // registered components.
+  class Observer {
+   public:
+    enum Events {
+      // Sent when the component updater starts doing update checks.
+      COMPONENT_UPDATER_STARTED,
+
+      // Sent when the component updater is going to take a long nap.
+      COMPONENT_UPDATER_SLEEPING,
+
+      // Sent when there is a new version of a registered component. After
+      // the notification is sent the component will be downloaded.
+      COMPONENT_UPDATE_FOUND,
+
+      // Sent when the new component has been downloaded and an installation
+      // or upgrade is about to be attempted.
+      COMPONENT_UPDATE_READY,
+
+      // Sent when a component has been successfully updated.
+      COMPONENT_UPDATED,
+
+      // Sent when a component has not been updated following an update check:
+      // either there was no update available, or an update failed.
+      COMPONENT_NOT_UPDATED,
+    };
+
+    virtual ~Observer() {}
+
+    // The component updater service will call this function when an interesting
+    // state change happens. If the |id| is specified, then the event is fired
+    // on behalf of a specific component. The implementors of this interface are
+    // expected to filter the relevant events based on the component id.
+    virtual void OnEvent(Events event, const std::string& id) = 0;
+  };
+
+  // Adds an observer for this class. An observer should not be added more
+  // than once. The caller retains the ownership of the observer object.
+  virtual void AddObserver(Observer* observer) = 0;
+
+  // Removes an observer. It is safe for an observer to be removed while
+  // the observers are being notified.
+  virtual void RemoveObserver(Observer* observer) = 0;
+
   // Start doing update checks and installing new versions of registered
   // components after Configurator::InitialDelay() seconds.
   virtual Status Start() = 0;
 
   // Stop doing update checks. In-flight requests and pending installations
   // will not be canceled.
   virtual Status Stop() = 0;
 
   // Add component to be checked for updates. You can call this method
   // before calling Start().
@@ skipping 16 matching lines @@
  private:
   // Ask the component updater to do an update check for a previously
   // registered component, immediately. If an update or check is already
   // in progress, returns |kInProgress|.
   // There is no guarantee that the item will actually be updated,
   // since an update may not be available. Listeners for the component will
   // know the outcome of the check.
   virtual Status OnDemandUpdate(const std::string& component_id) = 0;
 };
 
+typedef ComponentUpdateService::Observer ServiceObserver;
+
 // Creates the component updater. You must pass a valid |config| allocated on
 // the heap which the component updater will own.
 ComponentUpdateService* ComponentUpdateServiceFactory(
     ComponentUpdateService::Configurator* config);
 
 }  // namespace component_updater
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_