Adding a user list (to be consumed by GCM Client Implementation)

google_apis/gcm/engine/user_list.h

Index: google_apis/gcm/engine/user_list.h
diff --git a/google_apis/gcm/engine/user_list.h b/google_apis/gcm/engine/user_list.h
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+++ b/google_apis/gcm/engine/user_list.h
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+// Copyright 2014 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 GOOGLE_APIS_GCM_ENGINE_USER_LIST_H_
+#define GOOGLE_APIS_GCM_ENGINE_USER_LIST_H_
+
+#include <map>
+#include <string>
+
+#include "base/callback.h"
+#include "google_apis/gcm/engine/gcm_store.h"
+#include "google_apis/gcm/gcm_client.h"
+
+namespace gcm {
+
+GCM_EXPORT extern const int64 kInvalidSerialNumber;
+
+// UserList stores mappings between usernames, serial numbers and delegates to
+// enable dispatching messages to applications.
+class GCM_EXPORT UserList {
+ public:
+  // A callback used by SetDelegate method to return a |user_serial_number|
+  // assigned to the delegate identified by |username|.
+  typedef base::Callback<void(const std::string& username,
+                              int64 user_serial_number)> SetDelegateCallback;
+
+  explicit UserList(GCMStore* gcm_store);
+  ~UserList();
+
+  // Initializes the User List with a set of mappings and next serial number.
+  void Initialize(const GCMStore::SerialNumberMappings& result);
+
+  // Sets a user delegate for |username|. It will create a new entry for the
+  // user if one does not exist.
+  void SetDelegate(const std::string& username,
+                   GCMClient::Delegate* delegate,
+                   const SetDelegateCallback& callback);
+
+  // Returns a delegate for the user identified by |serial_number| or NULL, if
+  // a matching delegate was not found.
+  GCMClient::Delegate* GetDelegateBySerialNumber(int64 serial_number) const;
+
+  // Returns a delegate for the user identified by |username| or NULL, if a
+  // matching delegate was not found.
+  GCMClient::Delegate* GetDelegateByUsername(const std::string& username) const;
+
+  // Gets the serial number assigned to a specified |username|, if one is
+  // assigned, the value will be positive. If there is no matching delegate or
+  // it is not yet assigned a serial number, the result will be equal to
+  // kInvalidSerialNumber.
+  int64 GetSerialNumberForUsername(const std::string& username) const;
+
+ private:
+  friend class UserListTest;
+
+  struct UserInfo {
+    UserInfo();
+    explicit UserInfo(int64 serial_number);
+    UserInfo(GCMClient::Delegate* delegate,
+             const SetDelegateCallback& callback);
+    ~UserInfo();
+
+    int64 serial_number;
+    // Delegate related to the username. Not owned by the UserDelegate.
+    GCMClient::Delegate* delegate;
+    SetDelegateCallback callback;
+  };
+  typedef std::map<std::string, UserInfo> UserInfoMap;
+
+  // Assigns a serial number to the user identitified by |username|.
+  void AssignSerialNumber(const std::string& username);
+
+  // A callback invoked once the Backend is done updating the next serial
+  // number.
+  void IncrementSerialNumberCompleted(const std::string& username,
+                                      int64 user_serial_number,
+                                      bool success);
+
+  // Callback for serial number completion.
+  void AssignSerialNumberCompleted(const std::string& username, bool success);
+
+  // Concludes the process of setting a delegate by running a callback with
+  // |username| and |serial_number| assigned to that |username|. It will also
+  // reset the callback, so that it is not called again.
+  void OnSerialNumberReady(const UserInfoMap::iterator& iter);
+
+  // Sets the serial number related to the username. It expects the entry to not
+  // exist yet and will create it.
+  void SetSerialNumber(const std::string& username, int64 serial_number);
+
+  bool initialized_;
+  int64 next_serial_number_;
+  UserInfoMap delegates_;
+  GCMStore* gcm_store_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserList);
+};
+
+}  // namespace gcm
+
+#endif  // GOOGLE_APIS_GCM_ENGINE_USER_LIST_H_