Cleanup PushMessagingAppIdentifier

chrome/browser/push_messaging/push_messaging_app_identifier.h

 // 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 CHROME_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_APP_IDENTIFIER_H_
 #define CHROME_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_APP_IDENTIFIER_H_
 
+#include <stdint.h>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/logging.h"
 #include "url/gurl.h"
 
 class Profile;
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 // The prefix used for all push messaging application ids.
 extern const char kPushMessagingAppIdentifierPrefix[];
 
-// Type used to identify a web app from a Push API perspective.
-// These can be persisted to disk, in a 1:1 mapping between app_id and
-// pair<origin, service_worker_registration_id>.
+// Type used to identify a Service Worker registration from a Push API
+// perspective. These can be persisted to prefs, in a 1:1 mapping between
+// app_id and pair<origin, service_worker_registration_id>.
 class PushMessagingAppIdentifier {
  public:
   // Register profile-specific prefs.
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // Generates a new app identifier with random app_id.
   static PushMessagingAppIdentifier Generate(
       const GURL& origin,
-      int64 service_worker_registration_id);
+      int64_t service_worker_registration_id);
 
-  // Looks up an app identifier by app_id. Will be invalid if not found.
+  // Looks up an app identifier by app_id. If not found, is_null() will be true.
   static PushMessagingAppIdentifier Get(Profile* profile,
                                         const std::string& app_id);
 
   // Looks up an app identifier by origin & service worker registration id.
-  // Will be invalid if not found.
+  // If not found, is_null() will be true.
   static PushMessagingAppIdentifier Get(Profile* profile,
                                         const GURL& origin,
-                                        int64 service_worker_registration_id);
+                                        int64_t service_worker_registration_id);
 
   // Returns all the PushMessagingAppIdentifiers currently registered for the
   // given |profile|.
   static std::vector<PushMessagingAppIdentifier> GetAll(Profile* profile);
 
   ~PushMessagingAppIdentifier();
 
-  // Persist this app identifier to disk.
-  void PersistToDisk(Profile* profile) const;
+  // Persist this app identifier to prefs.
+  void PersistToPrefs(Profile* profile) const;
 
-  // Delete this app identifier from disk.
-  void DeleteFromDisk(Profile* profile) const; // TODO: Does const make sense?
+  // Delete this app identifier from prefs.
+  void DeleteFromPrefs(Profile* profile) const;
 
-  bool IsValid() const;
+  // Returns true if this identifier does not represent an app (i.e. this was
+  // returned by a failed call to Get).
+  bool is_null() const { return service_worker_registration_id_ < 0; }
 
-  const std::string& app_id() const { return app_id_; }
-  const GURL& origin() const { return origin_; }
-  int64 service_worker_registration_id() const {
+  // String that should be passed to push services like GCM to identify a
+  // particular Service Worker (so we can route incoming messages). Example:
+  // wp:9CC55CCE-B8F9-4092-A364-3B0F73A3AB5F
+  const std::string& app_id() const {
+    DCHECK(!is_null());
+    return app_id_;
+  }
+
+  const GURL& origin() const {
+    DCHECK(!is_null());
+    return origin_;
+  }
+
+  int64_t service_worker_registration_id() const {
+    DCHECK(!is_null());
     return service_worker_registration_id_;
   }
 
  private:
   friend class PushMessagingAppIdentifierTest;
 
   // Constructs an invalid app identifier.
   PushMessagingAppIdentifier();
   // Constructs a valid app identifier.
   PushMessagingAppIdentifier(const std::string& app_id,
                              const GURL& origin,
-                             int64 service_worker_registration_id);
+                             int64_t service_worker_registration_id);
+
+  // Validates that all the fields contain valid values.
+  void DCheckValid() const;
 
   std::string app_id_;
   GURL origin_;
-  int64 service_worker_registration_id_;
+  int64_t service_worker_registration_id_;
 };
 
 #endif  // CHROME_BROWSER_PUSH_MESSAGING_PUSH_MESSAGING_APP_IDENTIFIER_H_