gecko-dev/storage/public/mozIStorageConnection.idl

/* -*- Mode: idl; tab-width: 2; 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/. */

#include "nsISupports.idl"

interface mozIStorageAggregateFunction;
interface mozIStorageCompletionCallback;
interface mozIStorageFunction;
interface mozIStorageProgressHandler;
interface mozIStorageBaseStatement;
interface mozIStorageStatement;
interface mozIStorageAsyncStatement;
interface mozIStorageStatementCallback;
interface mozIStoragePendingStatement;
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.
 *
 * @threadsafe
 */
[scriptable, uuid(b2a4b534-f92e-4387-9bd9-d10408173925)]
interface mozIStorageConnection : nsISupports {
  /**
   * The default size for SQLite database pages used by mozStorage for new
   * databases.
   * This value must stay in sync with the SQLITE_DEFAULT_PAGE_SIZE define in
   * /db/sqlite3/src/Makefile.in
   */
  const long DEFAULT_PAGE_SIZE = 32768;

  /**
   * Closes a database connection.  Callers must finalize all statements created
   * for this connection prior to calling this method.  It is illegal to use
   * call this method if any asynchronous statements have been executed on this
   * connection.
   *
   * @throws NS_ERROR_UNEXPECTED
   *         If any statement has been executed asynchronously on this object.
   * @throws NS_ERROR_UNEXPECTED
   *         If is called on a thread other than the one that opened it.
   */
  void close();

  /**
   * Asynchronously closes a database connection, allowing all pending
   * asynchronous statements to complete first.
   *
   * @param aCallback [optional]
   *        A callback that will be notified when the close is completed.
   *
   * @throws NS_ERROR_UNEXPECTED
   *         If is called on a thread other than the one that opened it.
   */
  void asyncClose([optional] in mozIStorageCompletionCallback aCallback);

  /**
   * Clones a database and makes the clone read only if needed.
   *
   * @note If your connection is already read-only, you will get a read-only
   *       clone.
   * @note Due to a bug in SQLite, if you use the shared cache (openDatabase),
   *       you end up with the same privileges as the first connection opened
   *       regardless of what is specified in aReadOnly.
   * @note The following pragmas are copied over to a read-only clone:
   *        - cache_size
   *        - temp_store
   *       The following pragmas are copied over to a writeable clone:
   *        - cache_size
   *        - temp_store
   *        - foreign_keys
   *        - journal_size_limit
   *        - synchronous
   *        - wal_autocheckpoint
   *
   * @throws NS_ERROR_UNEXPECTED
   *         If this connection is a memory database.
   *
   * @param aReadOnly
   *        If true, the returned database should be put into read-only mode.
   *        Defaults to false.
   * @return the cloned database connection.
   */
  mozIStorageConnection clone([optional] in boolean aReadOnly);

  /**
   * Indicates if the connection is open and ready to use.  This will be false
   * if the connection failed to open, or it has been closed.
   */
  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;

  /**
   * affectedRows returns the number of database rows that were changed or
   * inserted or deleted by last operation.
   */
  readonly attribute long affectedRows;

  /**
   * 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,
   * ?1, ?2 etc. to indicate specific numbered arguments or :name and 
   * $var to indicate named arguments.
   *
   * @param aSQLStatement
   *        The SQL statement to execute.
   * @return a new mozIStorageStatement
   */
  mozIStorageStatement createStatement(in AUTF8String aSQLStatement);

  /**
   * Create an asynchronous statement (mozIStorageAsyncStatement) for the given
   * SQL expression.  An asynchronous statement can only be used to dispatch
   * asynchronous requests to the asynchronous execution thread and cannot be
   * used to take any synchronous actions on the database.
   *
   * The expression may use ? to indicate sequential numbered arguments,
   * ?1, ?2 etc. to indicate specific numbered arguments or :name and
   * $var to indicate named arguments.
   *
   * @param aSQLStatement
   *        The SQL statement to execute.
   * @return a new mozIStorageAsyncStatement
   */
  mozIStorageAsyncStatement createAsyncStatement(in AUTF8String aSQLStatement);

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

  /**
   * Execute an array of queries created with this connection asynchronously
   * using any currently bound parameters.  The statements are ran wrapped in a
   * transaction.  These statements 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 aStatements
   *        The array of statements to execute asynchronously, in the order they
   *        are given in the array.
   * @param aNumStatements
   *        The number of statements in aStatements.
   * @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(
    [array, size_is(aNumStatements)] in mozIStorageBaseStatement aStatements,
    in unsigned long aNumStatements,
    [optional] in mozIStorageStatementCallback aCallback
  );

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

  /**
   * Check if the given index exists.
   *
   * @param aIndexName   The index to check
   * @return 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 int32_t TRANSACTION_DEFERRED = 0;
  const int32_t TRANSACTION_IMMEDIATE = 1;
  const int32_t TRANSACTION_EXCLUSIVE = 2;
  void beginTransactionAs(in int32_t transactionType);

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

  /**
   * Rolls back the current transaction.  If no transaction is active,
   * @throws NS_ERROR_UNEXPECTED.
   * @throws NS_ERROR_NOT_INITIALIZED.
   */
  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 SQL function.  If you use your connection on multiple threads,
   * your function needs to be threadsafe, or it should only be called on one
   * thread.
   *
   * @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 SQL aggregate function.  If you use your connection on
   * multiple threads, your function needs to be threadsafe, or it should only
   * be called on one thread.
   *
   * @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 SQL 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.  This progress
   * handler should be threadsafe if you use this connection object on more than
   * one thread.
   *
   * @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 int32_t aGranularity,
                                                in mozIStorageProgressHandler aHandler);

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

  /**
   * Controls SQLITE_FCNTL_CHUNK_SIZE setting in sqlite. This helps avoid fragmentation
   * by growing/shrinking the database file in SQLITE_FCNTL_CHUNK_SIZE increments. To
   * conserve memory on systems short on storage space, this function will have no effect
   * on mobile devices or if less than 500MiB of space is left available.
   *
   * @param aIncrement
   *        The database file will grow in multiples of chunkSize.
   * @param aDatabaseName
   *        Sqlite database name. "" means pass NULL for zDbName to sqlite3_file_control.
   *        See http://sqlite.org/c3ref/file_control.html for more details.
   * @throws NS_ERROR_FILE_TOO_BIG
   *         If the system is short on storage space.
   */
  void setGrowthIncrement(in int32_t aIncrement, in AUTF8String aDatabaseName);

  /**
   * Enable a predefined virtual table implementation.
   *
   * @param aModuleName
   *        The module to enable. Only "filesystem" is currently supported.
   *
   * @throws NS_ERROR_FAILURE
   *         For unknown module names.
   */
  [noscript] void enableModule(in ACString aModuleName);
};