components/password_manager/core/browser/log_router.h

   1 // Copyright 2014 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_PASSWORD_MANAGER_CORE_BROWSER_LOG_ROUTER_H_
   6 #define COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_LOG_ROUTER_H_
   7
   8 #include <set>
   9 #include <string>
  10
  11 #include "base/macros.h"
  12 #include "base/observer_list.h"
  13
  14 namespace password_manager {
  15
  16 class LogReceiver;
  17 class PasswordManagerClient;
  18
  19 // The router stands between PasswordManagerClient instances and log receivers.
  20 // During the process of saving a password, the password manager code generates
  21 // the log strings, and passes them to the router. The router distributes the
  22 // logs to the receivers for displaying.
  23 class LogRouter {
  24  public:
  25   LogRouter();
  26   virtual ~LogRouter();
  27
  28   // Passes logs to the router. Only call when there are receivers registered.
  29   void ProcessLog(const std::string& text);
  30
  31   // All four (Unr|R)egister* methods below are safe to call from the
  32   // constructor of the registered object, because they do not call that object,
  33   // and the router only runs on a single thread.
  34
  35   // The clients must register to be notified about whether there are some
  36   // receivers or not. RegisterClient adds |client| to the right observer list
  37   // and returns true iff there are some receivers registered.
  38   bool RegisterClient(PasswordManagerClient* client);
  39   // Remove |client| from the observers list.
  40   void UnregisterClient(PasswordManagerClient* client);
  41
  42   // The receivers must register to get updates with new logs in the future.
  43   // RegisterReceiver adds |receiver| to the right observer list, and returns
  44   // the logs accumulated so far. (It returns by value, not const ref, to
  45   // provide a snapshot as opposed to a link to |accumulated_logs_|.)
  46   std::string RegisterReceiver(LogReceiver* receiver);
  47   // Remove |receiver| from the observers list.
  48   void UnregisterReceiver(LogReceiver* receiver);
  49
  50  private:
  51   // Observer lists for clients and receivers. The |true| in the template
  52   // specialisation means that they will check that all observers were removed
  53   // on destruction.
  54   base::ObserverList<PasswordManagerClient, true> clients_;
  55   base::ObserverList<LogReceiver, true> receivers_;
  56
  57   // Logs accumulated since the first receiver was registered.
  58   std::string accumulated_logs_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(LogRouter);
  61 };
  62
  63 }  // namespace password_manager
  64
  65 #endif  // COMPONENTS_PASSWORD_MANAGER_CORE_BROWSER_LOG_ROUTER_H_