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 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* vim: set ts=8 sts=2 et sw=2 tw=80: */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #ifndef mozilla_places_History_h_

 #define mozilla_places_History_h_

 #include "mozilla/IHistory.h"

 #include "mozilla/MemoryReporting.h"

 #include "mozilla/Mutex.h"

 #include "mozIAsyncHistory.h"

 #include "nsIDownloadHistory.h"

 #include "Database.h"

 #include "mozilla/dom/Link.h"

 #include "nsTHashtable.h"

 #include "nsString.h"

 #include "nsURIHashKey.h"

 #include "nsTObserverArray.h"

 #include "nsDeque.h"

 #include "nsIMemoryReporter.h"

 #include "nsIObserver.h"

 #include "mozIStorageConnection.h"

 namespace mozilla {

 namespace places {

 struct VisitData;

 #define NS_HISTORYSERVICE_CID \

   {0x0937a705, 0x91a6, 0x417a, {0x82, 0x92, 0xb2, 0x2e, 0xb1, 0x0d, 0xa8, 0x6c}}

 // Max size of History::mRecentlyVisitedURIs

 #define RECENTLY_VISITED_URI_SIZE 8

 class History : public IHistory

               , public nsIDownloadHistory

               , public mozIAsyncHistory

               , public nsIObserver

               , public nsIMemoryReporter

 {

 public:

   NS_DECL_THREADSAFE_ISUPPORTS

   NS_DECL_IHISTORY

   NS_DECL_NSIDOWNLOADHISTORY

   NS_DECL_MOZIASYNCHISTORY

   NS_DECL_NSIOBSERVER

   NS_DECL_NSIMEMORYREPORTER

   History();

   /**

    * Obtains the statement to use to check if a URI is visited or not.

    */

   mozIStorageAsyncStatement* GetIsVisitedStatement();

   /**

    * Adds an entry in moz_places with the data in aVisitData.

    *

    * @param aVisitData

    *        The visit data to use to populate a new row in moz_places.

    */

   nsresult InsertPlace(const VisitData& aVisitData);

   /**

    * Updates an entry in moz_places with the data in aVisitData.

    *

    * @param aVisitData

    *        The visit data to use to update the existing row in moz_places.

    */

   nsresult UpdatePlace(const VisitData& aVisitData);

   /**

    * Loads information about the page into _place from moz_places.

    *

    * @param _place

    *        The VisitData for the place we need to know information about.

    * @param [out] _exists

    *        Whether or the page was recorded in moz_places, false otherwise.

    */

   nsresult FetchPageInfo(VisitData& _place, bool* _exists);

   /**

    * Get the number of bytes of memory this History object is using,

    * including sizeof(*this))

    */

   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);

   /**

    * Obtains a pointer to this service.

    */

   static History* GetService();

   /**

    * Obtains a pointer that has had AddRef called on it.  Used by the service

    * manager only.

    */

   static History* GetSingleton();

   template<int N>

   already_AddRefed<mozIStorageStatement>

   GetStatement(const char (&aQuery)[N])

   {

     mozIStorageConnection* dbConn = GetDBConn();

     NS_ENSURE_TRUE(dbConn, nullptr);

     return mDB->GetStatement(aQuery);

   }

   already_AddRefed<mozIStorageStatement>

   GetStatement(const nsACString& aQuery)

   {

     mozIStorageConnection* dbConn = GetDBConn();

     NS_ENSURE_TRUE(dbConn, nullptr);

     return mDB->GetStatement(aQuery);

   }

   bool IsShuttingDown() const {

     return mShuttingDown;

   }

   Mutex& GetShutdownMutex() {

     return mShutdownMutex;

   }

   /**

    * Helper function to append a new URI to mRecentlyVisitedURIs. See

    * mRecentlyVisitedURIs.

    */

   void AppendToRecentlyVisitedURIs(nsIURI* aURI);

 private:

   virtual ~History();

   void InitMemoryReporter();

   /**

    * Obtains a read-write database connection.

    */

   mozIStorageConnection* GetDBConn();

   /**

    * The database handle.  This is initialized lazily by the first call to

    * GetDBConn(), so never use it directly, or, if you really need, always

    * invoke GetDBConn() before.

    */

   nsRefPtr<mozilla::places::Database> mDB;

   /**

    * A read-only database connection used for checking if a URI is visited.

    *

    * @note this should only be accessed by GetIsVisistedStatement and Shutdown.

    */

   nsCOMPtr<mozIStorageConnection> mReadOnlyDBConn;

   /**

    * An asynchronous statement to query if a URI is visited or not.

    *

    * @note this should only be accessed by GetIsVisistedStatement and Shutdown.

    */

   nsCOMPtr<mozIStorageAsyncStatement> mIsVisitedStatement;

   /**

    * Remove any memory references to tasks and do not take on any more.

    */

   void Shutdown();

   static History* gService;

   // Ensures new tasks aren't started on destruction.

   bool mShuttingDown;

   // This mutex guards mShuttingDown. Code running in other threads that might

   // schedule tasks that use the database should grab it and check the value of

   // mShuttingDown. If we are already shutting down, the code must gracefully

   // avoid using the db. If we are not, the lock will prevent shutdown from

   // starting in an unexpected moment.

   Mutex mShutdownMutex;

   typedef nsTObserverArray<mozilla::dom::Link* > ObserverArray;

   class KeyClass : public nsURIHashKey

   {

   public:

     KeyClass(const nsIURI* aURI)

     : nsURIHashKey(aURI)

     {

     }

     KeyClass(const KeyClass& aOther)

     : nsURIHashKey(aOther)

     {

       NS_NOTREACHED("Do not call me!");

     }

     ObserverArray array;

   };

   /**

    * Helper function for nsTHashtable::SizeOfExcludingThis call in

    * SizeOfIncludingThis().

    */

   static size_t SizeOfEntryExcludingThis(KeyClass* aEntry,

                                          mozilla::MallocSizeOf aMallocSizeOf,

                                          void*);

   nsTHashtable<KeyClass> mObservers;

   /**

    * mRecentlyVisitedURIs remembers URIs which are recently added to the DB,

    * to avoid saving these locations repeatedly in a short period.

    */

   typedef nsAutoTArray<nsCOMPtr<nsIURI>, RECENTLY_VISITED_URI_SIZE>

           RecentlyVisitedArray;

   RecentlyVisitedArray mRecentlyVisitedURIs;

   RecentlyVisitedArray::index_type mRecentlyVisitedURIsNextIndex;

   bool IsRecentlyVisitedURI(nsIURI* aURI);

 };

 } // namespace places

 } // namespace mozilla

 #endif // mozilla_places_History_h_