nsMsgDatabaseEnumerators.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* 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 _nsMsgDatabaseEnumerators_H_

#define _nsMsgDatabaseEnumerators_H_

/*

 * This file provides some enumerator classes, private to nsMsgDatabase.

 * The outside world would only ever see these as nsIMsgEnumerator or

 * nsIMsgThreadEnumerator.

 * These enumerators automatically register themselves with the nsMsgDatabase

 * during construction/destruction. This lets the database track all

 * outstanding enumerators, so they can be invalidated if the database is

 * destroyed or ForceClosed().

 * Due to this lifecycle coupling, we try to avoid using refcounted pointers

 * here, as we don't want outstanding enumerators to lock an otherwise unused

 * database in existence.

*/

#include "nsMsgEnumerator.h"

#include "nsCOMPtr.h"

#include "nsTArray.h"

#include "mdb.h"

#include "nsIDBChangeListener.h"

#include "nsIMsgSearchTerm.h"

#include "nsIMsgSearchSession.h"

class nsMsgDatabase;

class nsIMdbTable;

class nsIMdbTableRowCursor;

class nsIMsgFolder;

/**

 * Enumerates over messages, forwards or backward, with an optional filter fn.

*/

class nsMsgDBEnumerator : public nsBaseMsgEnumerator {

 public:

  // nsIMsgEnumerator support.

  NS_IMETHOD GetNext(nsIMsgDBHdr** aItem) override;

  NS_IMETHOD HasMoreElements(bool* aResult) override;

  // Function type for filtering which messages are enumerated.

  typedef nsresult (*nsMsgDBEnumeratorFilter)(nsIMsgDBHdr* hdr, void* closure);

  nsMsgDBEnumerator(nsMsgDatabase* db, nsIMdbTable* table,

                    nsMsgDBEnumeratorFilter filter, void* closure,

                    bool iterateForwards = true);

  // Called by db when no longer valid (db is being destroyed or ForcedClosed).

  void Invalidate();

 protected:

  // internals

  nsresult GetRowCursor();

  // Returns next message or nullptr if none more.

  virtual nsresult InternalGetNext(nsIMsgDBHdr** nextHdr);

  // Our source DB. Not refcounted, because we don't want to lock the DB

  // in existence. The enumerator is registered with the DB, and the DB will

  // call Invalidate() if it is destroyed or ForceClosed().

  nsMsgDatabase* mDB;

  nsCOMPtr<nsIMdbTableRowCursor> mRowCursor;

  mdb_pos mRowPos;

  nsCOMPtr<nsIMsgDBHdr> mResultHdr;

  bool mDone;

  bool mIterateForwards;

  nsMsgDBEnumeratorFilter mFilter;

  nsIMdbTable* mTable;

  void* mClosure;

  virtual ~nsMsgDBEnumerator() override;

};

/**

 * Enumerate over messages which match the given search terms.

*/

class nsMsgFilteredDBEnumerator : public nsMsgDBEnumerator {

 public:

  nsMsgFilteredDBEnumerator(nsMsgDatabase* db, nsIMdbTable* table,

                            bool reverse);

  virtual ~nsMsgFilteredDBEnumerator() override;

  nsresult InitSearchSession(

      const nsTArray<RefPtr<nsIMsgSearchTerm>>& searchTerms,

      nsIMsgFolder* folder);

 protected:

  virtual nsresult InternalGetNext(nsIMsgDBHdr** nextHdr) override;

  nsCOMPtr<nsIMsgSearchSession> m_searchSession;

};

/**

 * Helper class for fetching message threads from a database.

 * This enumerator automatically registers itself with the nsMsgDatabase.

 * If the DB is destroyed or ForceClosed() it will call the enumerators

 * Invalidate() method.

*/

class nsMsgDBThreadEnumerator : public nsBaseMsgThreadEnumerator {

 public:

  // nsIMsgThreadEnumerator support.

  NS_IMETHOD GetNext(nsIMsgThread** aItem) override;

  NS_IMETHOD HasMoreElements(bool* aResult) override;

  // Function type for filtering threads that appear in the enumeration.

  typedef nsresult (*nsMsgDBThreadEnumeratorFilter)(nsIMsgThread* thread);

  nsMsgDBThreadEnumerator(nsMsgDatabase* db,

                          nsMsgDBThreadEnumeratorFilter filter);

  // Called by DB when being destroyed or ForcedClosed.

  void Invalidate();

 protected:

  virtual ~nsMsgDBThreadEnumerator();

  nsresult GetTableCursor(void);

  nsresult PrefetchNext();

  // Our source DB. Not refcounted, because we don't want to lock the DB

  // in existence. The enumerator is registered with the DB, and the DB will

  // call Invalidate() if it is destroyed or ForceClosed().

  nsMsgDatabase* mDB;

  nsCOMPtr<nsIMdbPortTableCursor> mTableCursor;

  RefPtr<nsIMsgThread> mResultThread;

  bool mDone;

  bool mNextPrefetched;

  nsMsgDBThreadEnumeratorFilter mFilter;

};

#endif  // _nsMsgDatabaseEnumerators_H_