Prevent duplicate concurrent installs of the same extension

chrome/browser/extensions/install_tracker.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_INSTALL_TRACKER_H_
 #define CHROME_BROWSER_EXTENSIONS_INSTALL_TRACKER_H_
 
+#include <map>
+
 #include "base/observer_list.h"
 #include "base/prefs/pref_change_registrar.h"
+#include "base/scoped_observer.h"
 #include "chrome/browser/extensions/install_observer.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
+#include "extensions/browser/extension_registry_observer.h"
 
 class Profile;
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 
 class ExtensionPrefs;
+class ExtensionRegistry;
 
 class InstallTracker : public KeyedService,
-                       public content::NotificationObserver {
+                       public content::NotificationObserver,
+                       public ExtensionRegistryObserver {
  public:
+  // Details of an active installation.
+  struct InstallProgressData {
+   public:
+    InstallProgressData();
+    explicit InstallProgressData(const std::string& extension_id);
+
+    std::string extension_id;
+    int percent_downloaded;
+    bool is_ephemeral;
+  };
+
   InstallTracker(Profile* profile,
                  extensions::ExtensionPrefs* prefs);
   virtual ~InstallTracker();
 
   static InstallTracker* Get(content::BrowserContext* context);
 
   void AddObserver(InstallObserver* observer);
   void RemoveObserver(InstallObserver* observer);
 
+  // If an install is currently in progress for |extension_id|, returns details
+  // of the installation. This instance retains ownership of the returned
+  // pointer. Returns NULL if the extension is not currently being installed.
+  const InstallProgressData* GetActiveInstall(
+      const std::string& extension_id) const;
+
+  // Registers an install initiated by the user to allow checking of duplicate
+  // installs. Download of the extension has not necessarily started.
+  // RemoveActiveInstall() must be called when install is complete regardless of
+  // success or failure.
+  void AddActiveInstall(const InstallProgressData& install_data);
+
+  // Deregisters an active install.
+  void RemoveActiveInstall(const std::string& extension_id);
+
   void OnBeginExtensionInstall(
       const InstallObserver::ExtensionInstallParams& params);
   void OnBeginExtensionDownload(const std::string& extension_id);
   void OnDownloadProgress(const std::string& extension_id,
                           int percent_downloaded);
   void OnBeginCrxInstall(const std::string& extension_id);
   void OnFinishCrxInstall(const std::string& extension_id, bool success);
   void OnInstallFailure(const std::string& extension_id);
 
   // NOTE(limasdf): For extension [un]load and [un]installed, use
   //                ExtensionRegistryObserver.
 
   // Overriddes for KeyedService.
   virtual void Shutdown() OVERRIDE;
 
  private:
   void OnAppsReordered();
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // ExtensionRegistryObserver implementation.
+  virtual void OnExtensionInstalled(content::BrowserContext* browser_context,
+                                    const Extension* extension) OVERRIDE;
+
+  // Maps extension id to the details of an active install.
+  typedef std::map<std::string, InstallProgressData> ActiveInstallsMap;
+  ActiveInstallsMap active_installs_;
+
   ObserverList<InstallObserver> observers_;
   content::NotificationRegistrar registrar_;
   PrefChangeRegistrar pref_change_registrar_;
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
+      extension_registry_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(InstallTracker);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_INSTALL_TRACKER_H_