components/update_client/action.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 COMPONENTS_UPDATE_CLIENT_ACTION_H_
   6 #define COMPONENTS_UPDATE_CLIENT_ACTION_H_
   7
   8 #include <string>
   9
  10 #include "base/callback.h"
  11 #include "base/macros.h"
  12 #include "base/threading/thread_checker.h"
  13 #include "components/update_client/crx_update_item.h"
  14 #include "components/update_client/update_client.h"
  15
  16 namespace update_client {
  17
  18 class Configurator;
  19 struct CrxUpdateItem;
  20 struct UpdateContext;
  21
  22 // Any update can be broken down as a sequence of discrete steps, such as
  23 // checking for updates, downloading patches, updating, and waiting between
  24 // successive updates. An action is the smallest unit of work executed by
  25 // the update engine.
  26 //
  27 // Defines an abstract interface for a unit of work, executed by the
  28 // update engine as part of an update.
  29 class Action {
  30  public:
  31   enum class ErrorCategory {
  32     kErrorNone = 0,
  33     kNetworkError,
  34     kUnpackError,
  35     kInstallError,
  36     kServiceError,  // Runtime errors which occur in the service itself.
  37   };
  38
  39   enum class ServiceError {
  40     ERROR_WAIT = 1,
  41   };
  42
  43   using Callback = base::Callback<void(int error)>;
  44   virtual ~Action() {}
  45
  46   // Runs the code encapsulated by the action. When an action completes, it can
  47   // chain up and transfer the execution flow to another action or it can
  48   // invoke the |callback| when this function has completed and there is nothing
  49   // else to do.
  50   virtual void Run(UpdateContext* update_context, Callback callback) = 0;
  51 };
  52
  53 // Provides a reusable implementation of common functions needed by actions.
  54 class ActionImpl {
  55  protected:
  56   ActionImpl();
  57   ~ActionImpl();
  58
  59   void Run(UpdateContext* update_context, Action::Callback callback);
  60
  61   // Changes the current state of the |item| to the new state |to|.
  62   void ChangeItemState(CrxUpdateItem* item, CrxUpdateItem::State to);
  63
  64   // Changes the state of all items in |update_context_|. Returns the count
  65   // of items affected by the call.
  66   size_t ChangeAllItemsState(CrxUpdateItem::State from,
  67                              CrxUpdateItem::State to);
  68
  69   // Returns the item associated with the component |id| or nullptr in case
  70   // of errors.
  71   CrxUpdateItem* FindUpdateItemById(const std::string& id) const;
  72
  73   void NotifyObservers(UpdateClient::Observer::Events event,
  74                        const std::string& id);
  75
  76   // Updates the CRX at the front of the CRX queue in this update context.
  77   void UpdateCrx();
  78
  79   // Completes updating the CRX at the front of the queue, and initiates
  80   // the update for the next CRX in the queue, if the queue is not empty.
  81   void UpdateCrxComplete(CrxUpdateItem* item);
  82
  83   // Called when the updates for all CRXs have finished and the execution
  84   // flow must return back to the update engine.
  85   void UpdateComplete(int error);
  86
  87   base::ThreadChecker thread_checker_;
  88
  89   UpdateContext* update_context_;  // Not owned by this class.
  90   Action::Callback callback_;
  91
  92  private:
  93   DISALLOW_COPY_AND_ASSIGN(ActionImpl);
  94 };
  95
  96 }  // namespace update_client
  97
  98 #endif  // COMPONENTS_UPDATE_CLIENT_ACTION_H_