chrome/browser/task_management/providers/task_provider.h

   1 // Copyright 2015 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 CHROME_BROWSER_TASK_MANAGEMENT_PROVIDERS_TASK_PROVIDER_H_
   6 #define CHROME_BROWSER_TASK_MANAGEMENT_PROVIDERS_TASK_PROVIDER_H_
   7
   8 #include "chrome/browser/task_management/providers/task_provider_observer.h"
   9
  10 namespace task_management {
  11
  12 // Defines the interface for task providers. A concrete task provider must be
  13 // able to collect all the tasks of a particular type which this provider
  14 // supports as well as track any tasks addition / removal. Once StartUpdating()
  15 // is called, the provider is responsible for notifying the observer about the
  16 // tasks it's tracking. The TaskProviders own the tasks they provide.
  17 class TaskProvider {
  18  public:
  19   TaskProvider();
  20   virtual ~TaskProvider();
  21
  22   // Should return the task associated to the specified IDs from a
  23   // |content::ResourceRequestInfo| that represents a |URLRequest|. A value of
  24   // nullptr will be returned if the desired task does not belong to this
  25   // provider.
  26   //
  27   // |origin_pid| is the PID of the originating process of the URLRequest, if
  28   // the request is sent on behalf of another process. Otherwise it's 0.
  29   // |child_id| is the unique ID of the host of the child process requestor.
  30   // |route_id| is the ID of the IPC route for the URLRequest (this identifies
  31   // the RenderView or like-thing in the renderer that the request gets routed
  32   // to).
  33   virtual Task* GetTaskOfUrlRequest(int origin_pid,
  34                                     int child_id,
  35                                     int route_id) = 0;
  36
  37   // Set the sole observer of this provider. It's an error to set an observer
  38   // if there's already one there.
  39   void SetObserver(TaskProviderObserver* observer);
  40
  41   // Clears the currently set observer for this provider. It's an error to clear
  42   // the observer if there's no one set.
  43   void ClearObserver();
  44
  45  protected:
  46   // Used by concrete task providers to notify the observer of tasks addition/
  47   // removal. These methods should only be called after StartUpdating() has been
  48   // called and before StopUpdating() is called.
  49   void NotifyObserverTaskAdded(Task* task) const;
  50   void NotifyObserverTaskRemoved(Task* task) const;
  51
  52  private:
  53   // This will be called once an observer is set for this provider. When it is
  54   // called, the concrete provider must notify the observer of all pre-existing
  55   // tasks as well as track new addition and terminations and notify the
  56   // observer of these changes.
  57   virtual void StartUpdating() = 0;
  58
  59   // This will be called once the observer is cleared, at which point the
  60   // provider can stop tracking tasks addition / removal and can clear its own
  61   // resources.
  62   virtual void StopUpdating() = 0;
  63
  64   // We support only one single obsever which will be the sampler in this case.
  65   TaskProviderObserver* observer_;
  66
  67   DISALLOW_COPY_AND_ASSIGN(TaskProvider);
  68 };
  69
  70 }  // namespace task_management
  71
  72 #endif  // CHROME_BROWSER_TASK_MANAGEMENT_PROVIDERS_TASK_PROVIDER_H_