informix/lib/cursor.js

A node.js native client for IBM Informix

'use strict';

var uuid = require( 'uuid' );


/**
*   Class representing a cursor to a resultset
*
*   @constructor
*   @param {Connection} conn - Connection object
*   @param {Statement} stmt - Statement object
*   @param {object} [opts] - Constructor options
*   @param {string} [opts.id] - Cursor id to use
*/
var Cursor = function ( conn, stmt, opts ) {

	// privileged data
	this.$ = {
		conn : conn,
		ifx  : conn.ifx(),
		stmt : stmt
	};

	this.options( opts );

};


/**
*   Return the context ID associated with this cursor
*
*   @return {string} - Context ID
*/
Cursor.prototype.context = function () {
	return this.$.stmt.context();
};


/**
*   Return cursor ID
*
*   @return {string} - ID generated for this cursor object.
*/
Cursor.prototype.id = function () {
	return this.$.id;
};


/**
*   Close the results cursor
*
*   @return {Promise.<string, Error>} - A promise to string which would contain
*           the ID of the closed cursor or an Error if rejected.
*/
Cursor.prototype.close = function () {

	var self = this;

	return self.$.conn.acquire( self.context() )
		.then( function ( conn ) {
			return new Promise( function ( resolve, reject ) {
				self.$.ifx.close( self.$.id, function ( err, curid ) {
					if ( err ) {
						return reject( err );
					}

					self.$.conn.release( self.context() );

					if ( self.$.stmt && ( self.$.stmt.flags().reusable === false ) ) {
						self.$.stmt.free()
							.then( function ( stmtid ) {
								resolve( curid );
							} )
							.catch( reject );
					} else {
						resolve( curid );
					}
				} );
			} );
		} )
		.catch( function ( err ) {
			self.$.conn.release( self.context() );
			throw err;
		} );

};


/**
*   Fetch a result
*
*   @return {Promise.<Array|null, Error>} A promise to a results array (or null
*           if no more results) or an Error if rejected.
*/
Cursor.prototype.fetch = function () {

	var self = this;

	return self.$.conn.acquire( self.context() )
		.then( function ( conn ) {
			return new Promise( function ( resolve, reject ) {
				self.$.ifx.fetch( self.$.id, function ( err, result ) {
					if ( err ) {
						return reject( err );
					}

					self.$.conn.release( self.context() );
					resolve( result );
				} );
			} );
		} )
		.catch( function ( err ) {
			self.$.conn.release( self.context() );
			throw err;
		} );

};


/**
*   Fetch all results
*
*   @param {object} [opts] - Options
*   @param {boolean} [opts.close=false] - Flag indicating to close the cursor after
*          fetching all results.
*
*   @return {Promise.<Array, Error>} A promise to an array of results or an
*           Error if rejected.
*/
Cursor.prototype.fetchAll = function ( opts ) {

	var self = this;

	if (! opts ) { opts = {}; }

	return self.$.conn.acquire( self.context() )
		.then( function ( conn ) {
			return new Promise( function ( resolve, reject ) {
				var results = [];
				var fetcher = function ( err, result ) {
					if ( err ) {
						return reject( err );
					}

					if ( result ) {
						results.push( result );
						return self.$.ifx.fetch( self.$.id, fetcher );
					}

					self.$.conn.release( self.context() );
					resolve( results );
				};

				self.$.ifx.fetch( self.$.id, fetcher );
			} );
		} )
		.catch( function ( err ) {
			self.$.conn.release( self.context() );
			throw err;
		} )
		.then( function ( results ) {
			if ( opts.close === true ) {
				return self.close()
					.then( function ( curid ) {
						return results;
					} );
			}

			return results;
		} );

};


/**
*   Set options
*
*   @param {object} opts - Options
*/
Cursor.prototype.options = function ( opts ) {
	this.$.opts = opts || {};

	if ( (typeof this.$.opts.id) === 'string' ) {
		this.$.id = this.$.opts.id;
	} else {
		this.$.id = '_' + uuid.v4().replace( /\-/g, 's' );
	}
};


/**
*   Return the serial value generated after executing an insert statement.
*
*   @return {number} - Generated serial value
*/
Cursor.prototype.serial = function () {
	return this.$.ifx.serial( this.$.id );
};



module.exports = Cursor;