/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=2 sts=2 et
 * 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/. */

#include "nsISupports.idl"
#include "mozIStorageBindingParams.idl"

interface mozIStorageConnection;
interface mozIStorageStatementCallback;
interface mozIStoragePendingStatement;
interface mozIStorageBindingParams;
interface mozIStorageBindingParamsArray;

/**
 * The base interface for both pure asynchronous storage statements 
 * (mozIStorageAsyncStatement) and 'classic' storage statements
 * (mozIStorageStatement) that can be used for both synchronous and asynchronous
 * purposes.
 */
[scriptable, uuid(16ca67aa-1325-43e2-aac7-859afd1590b2)]
interface mozIStorageBaseStatement : mozIStorageBindingParams {
  /**
   * Finalizes a statement so you can successfully close a database connection.
   * Once a statement has been finalized it can no longer be used for any
   * purpose.
   * 
   * Statements are implicitly finalized when their reference counts hits zero.
   * If you are a native (C++) caller this is accomplished by setting all of
   * your nsCOMPtr instances to be NULL.  If you are operating from JavaScript
   * code then you cannot rely on this behavior because of the involvement of
   * garbage collection.
   *
   * When finalizing an asynchronous statement you do not need to worry about
   * whether the statement has actually been executed by the asynchronous
   * thread; you just need to call finalize after your last call to executeAsync
   * involving the statement.  However, you do need to use asyncClose instead of
   * close on the connection if any statements have been used asynchronously.
   */
  void finalize();

  /**
   * Binds the array of parameters to the statement.  When executeAsync is
   * called, all the parameters in aParameters are bound and then executed.
   *
   * @param aParameters
   *        The array of parameters to bind to the statement upon execution.
   *
   * @note This is only works on statements being used asynchronously.
   */
  void bindParameters(in mozIStorageBindingParamsArray aParameters);

  /**
   * Creates a new mozIStorageBindingParamsArray that can be used to bind
   * multiple sets of data to a statement with bindParameters.
   *
   * @return a mozIStorageBindingParamsArray that multiple sets of parameters
   *         can be bound to.
   *
   * @note This is only useful for statements being used asynchronously.
   */
  mozIStorageBindingParamsArray newBindingParamsArray();

  /**
   * Execute a query asynchronously using any currently bound parameters.  This
   * statement can be reused immediately, and reset does not need to be called.
   *
   * @note If you have any custom defined functions, they must be re-entrant
   *       since they can be called on multiple threads.
   *
   * @param aCallback [optional]
   *        The callback object that will be notified of progress, errors, and
   *        completion.
   * @return an object that can be used to cancel the statements execution.
   */
  mozIStoragePendingStatement executeAsync(
    [optional] in mozIStorageStatementCallback aCallback
  );

  /**
   * The statement is not usable, either because it failed to initialize or
   * was explicitly finalized.
   */
  const long MOZ_STORAGE_STATEMENT_INVALID = 0;
  /**
   * The statement is usable.
   */
  const long MOZ_STORAGE_STATEMENT_READY = 1;
  /**
   * Indicates that the statement is executing and the row getters may be used.
   *
   * @note This is only relevant for mozIStorageStatement instances being used
   *       in a synchronous fashion.
   */
  const long MOZ_STORAGE_STATEMENT_EXECUTING = 2;

  /**
   * Find out whether the statement is usable (has not been finalized).
   */
  readonly attribute long state;

  /**
   * Escape a string for SQL LIKE search.
   *
   * @note Consumers will have to use same escape char when doing statements
   *       such as:   ...LIKE '?1' ESCAPE '/'...
   *
   * @param aValue
   *        The string to escape for SQL LIKE.
   * @param aEscapeChar
   *        The escape character.
   * @return an AString of an escaped version of aValue
   *         (%, _ and the escape char are escaped with the escape char)
   *         For example, we will convert "foo/bar_baz%20cheese" 
   *         into "foo//bar/_baz/%20cheese" (if the escape char is '/').
   */
  AString escapeStringForLIKE(in AString aValue, in wchar aEscapeChar);
};