gecko/storage/public/mozIStorageConnection.idl

/* -*- Mode: idl; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Oracle Corporation code.
 *
 * The Initial Developer of the Original Code is
 *  Oracle Corporation
 * Portions created by the Initial Developer are Copyright (C) 2004
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Vladimir Vukicevic <vladimir.vukicevic@oracle.com>
 *   Brett Wilson <brettw@gmail.com>
 *   Shawn Wilsher <me@shawnwilsher.com>
 *   Lev Serebryakov <lev@serebryakov.spb.ru>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
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 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsISupports.idl"

interface mozIStorageAggregateFunction;
interface mozIStorageFunction;
interface mozIStorageProgressHandler;
interface mozIStorageStatement;
interface nsIFile;

/**
 * mozIStorageConnection represents a database connection attached to
 * a specific file or to the in-memory data storage.  It is the
 * primary interface for interacting with a database, including
 * creating prepared statements, executing SQL, and examining database
 * errors.
 */
[scriptable, uuid(9f36de9d-6471-4249-afed-1ee7760e325c)]
interface mozIStorageConnection : nsISupports {
  /*
   * Initialization and status
   */

  /**
   * whether the database is open or not
   */
  readonly attribute boolean connectionReady;

  /**
   * The current database nsIFile.  Null if the database
   * connection refers to an in-memory database.
   */
  readonly attribute nsIFile databaseFile;

  /**
   * lastInsertRowID returns the row ID from the last INSERT
   * operation.
   */
  readonly attribute long long lastInsertRowID;

  /**
   * The last error SQLite error code.
   */
  readonly attribute long lastError;

  /**
   * The last SQLite error as a string (in english, straight from the
   * sqlite library).
   */
  readonly attribute AUTF8String lastErrorString;

  /**
   * The schema version of the database.  This should not be used until the 
   * database is ready.  The schema will be reported as zero if it is not set.
   */
  attribute long schemaVersion;

  /*
   * Statement creation
   */

  /**
   * Create a mozIStorageStatement for the given SQL expression.  The
   * expression may use ? to indicate sequential numbered arguments,
   * or :name and $var to indicate named arguments.
   *
   * @param aSQLStatement  The SQL statement to execute
   *
   * @returns a new mozIStorageStatement
   */
  mozIStorageStatement createStatement(in AUTF8String aSQLStatement);

  /**
   * Execute a SQL expression, expecting no arguments.
   *
   * @param aSQLStatement  The SQL statement to execute
   */
  void executeSimpleSQL(in AUTF8String aSQLStatement);

  /**
   * Check if the given table exists.
   *
   * @param aTableName   The table to check
   * @returns TRUE if table exists, FALSE otherwise.
   */
  boolean tableExists(in AUTF8String aTableName);

  /**
   * Check if the given index exists.
   *
   * @param aIndexName   The index to check
   * @returns TRUE if the index exists, FALSE otherwise.
   */
  boolean indexExists(in AUTF8String aIndexName);


  /*
   * Transactions
   */

  /**
   * Returns true if a transaction is active on this connection.
   */
  readonly attribute boolean transactionInProgress;

  /**
   * Begin a new transaction.  sqlite default transactions are deferred.
   * If a transaction is active, throws an error.
   */
  void beginTransaction();

  /**
   * Begins a new transaction with the given type.
   */
  const PRInt32 TRANSACTION_DEFERRED = 0;
  const PRInt32 TRANSACTION_IMMEDIATE = 1;
  const PRInt32 TRANSACTION_EXCLUSIVE = 2;
  void beginTransactionAs(in PRInt32 transactionType);

  /**
   * Commits the current transaction.  If no transaction is active,
   * @throws NS_ERROR_STORAGE_NO_TRANSACTION.
   */
  void commitTransaction();

  /**
   * Rolls back the current transaction.  If no transaction is active,
   * @throws NS_ERROR_STORAGE_NO_TRANSACTION.
   */
  void rollbackTransaction();

  /*
   * Tables
   */

  /**
   * Create the table with the given name and schema.
   *
   * If the table already exists, NS_ERROR_FAILURE is thrown.
   * (XXX at some point in the future it will check if the schema is
   * the same as what is specified, but that doesn't happen currently.)
   *
   * @param aTableName the table name to be created, consisting of
   * [A-Za-z0-9_], and beginning with a letter.
   *
   * @param aTableSchema the schema of the table; what would normally
   * go between the parens in a CREATE TABLE statement: e.g., "foo
   * INTEGER, bar STRING".
   *
   * @throws NS_ERROR_FAILURE if the table already exists or could not
   * be created for any other reason.
   *
   */
  void createTable(in string aTableName,
                   in string aTableSchema);

  /*
   * Functions
   */

  /**
   * Create a new SQLite function
   *
   * @param aFunctionName  The name of function to create, as seen in SQL.
   * @param aNumArguments  The number of arguments the function takes. Pass
   *                       -1 for variable-argument functions.
   * @param aFunction      The instance of mozIStorageFunction, which implements
   *                       the function in question.
   */
  void createFunction(in AUTF8String aFunctionName,
                      in long aNumArguments,
                      in mozIStorageFunction aFunction);

  /**
   * Create a new SQLite aggregate function
   *
   * @param aFunctionName  The name of aggregate function to create, as seen
   *                       in SQL.
   * @param aNumArguments  The number of arguments the function takes. Pass
   *                       -1 for variable-argument functions.
   * @param aFunction      The instance of mozIStorageAggreagteFunction,
   *                       which implements the function in question.
   */
  void createAggregateFunction(in AUTF8String aFunctionName,
                               in long aNumArguments,
                               in mozIStorageAggregateFunction aFunction);
  /**
   * Delete custom SQLite function (simple or aggregate one)
   *
   * @param aFunctionName  The name of function to remove.
   */
  void removeFunction(in AUTF8String aFunctionName);

  /**
   * Sets a progress handler. Only one handler can be registered at a time.
   * If you need more than one, you need to chain them yourself.
   *
   * @param aGranularity   The number of SQL virtual machine steps between
   *                       progress handler callbacks.
   * @param aHandler       The instance of mozIStorageProgressHandler.
   *
   * @return previous registered handler.
   */
  mozIStorageProgressHandler setProgressHandler(in PRInt32 aGranularity,
                                                in mozIStorageProgressHandler aHandler);

  /**
   * Remove a progress handler.
   *
   * @return previous registered handler.
   */
  mozIStorageProgressHandler removeProgressHandler();

  /*
   * Utilities
   */

  /**
   * Copies the current database file to the specified parent directory with the
   * specified file name.  If the parent directory is not specified, it places
   * the backup in the same directory as the current file.  This function
   * ensures that the file being created is unique.
   *
   * @param aFileName
   *        The name of the new file to create.
   * @param [optional] aParentDirectory
   *        The directory you'd like the file to be placed.
   * @return The nsIFile representing the backup file.
   */
  nsIFile backupDB(in AString aFileName,
                   [optional] in nsIFile aParentDirectory);

  /**
   * This is used to preload the database cache. It loads pages from the
   * start of the database file until the memory cache (specified by
   * "PRAGMA cache_size=") is full or the entire file is read.
   *
   * The cache MUST be active on the database for this to work. This means
   * that you must have a transaction open on the connection, or have a
   * transaction open on another connection that shares the same pager cache.
   * This cached data will go away when the transaction is closed.
   *
   * This preload operation can dramatically speed up read operations because
   * the data is loaded as one large block. Normally, pages are read in on
   * demand, which can cause many disk seeks.
   */
  void preload();
};