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index.js
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index.js
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var Result = require('./pg').Result
var prepare = require('./pg').prepareValue
var Cursor = function(text, values) {
this.text = text
this.values = values ? values.map(prepare) : null
this.connection = null
this._queue = []
this.state = 'initialized'
this._result = new Result()
this._cb = null
this._rows = null
}
Cursor.prototype.submit = function(connection) {
this.connection = connection
var con = connection
var self = this
con.parse({
text: this.text
}, true)
con.bind({
values: this.values
}, true)
con.describe({
type: 'P',
name: '' //use unamed portal
}, true)
con.flush()
con.once('noData', ifNoData)
con.once('rowDescription', function () {
con.removeListener('noData', ifNoData);
});
function ifNoData () {
self.state = 'idle'
self._shiftQueue();
}
}
Cursor.prototype._shiftQueue = function () {
if(this._queue.length) {
this._getRows.apply(this, this._queue.shift())
}
}
Cursor.prototype.handleRowDescription = function(msg) {
this._result.addFields(msg.fields)
this.state = 'idle'
this._shiftQueue();
}
Cursor.prototype.handleDataRow = function(msg) {
var row = this._result.parseRow(msg.fields)
this._rows.push(row)
}
Cursor.prototype._sendRows = function() {
this.state = 'idle'
setImmediate(function() {
var cb = this._cb
//remove callback before calling it
//because likely a new one will be added
//within the call to this callback
this._cb = null
if(cb) {
cb(null, this._rows)
}
this._rows = []
}.bind(this))
}
Cursor.prototype.handleCommandComplete = function() {
this.connection.sync()
}
Cursor.prototype.handlePortalSuspended = function() {
this._sendRows()
}
Cursor.prototype.handleReadyForQuery = function() {
this._sendRows()
this.state = 'done'
}
Cursor.prototype.handleError = function(msg) {
this.state = 'error'
this._error = msg
//satisfy any waiting callback
if(this._cb) {
this._cb(msg)
}
//dispatch error to all waiting callbacks
for(var i = 0; i < this._queue.length; i++) {
this._queue.pop()[1](msg)
}
//call sync to keep this connection from hanging
this.connection.sync()
}
Cursor.prototype._getRows = function(rows, cb) {
this.state = 'busy'
this._cb = cb
this._rows = []
var msg = {
portal: '',
rows: rows
}
this.connection.execute(msg, true)
this.connection.flush()
}
Cursor.prototype.end = function(cb) {
if(this.state != 'initialized') {
this.connection.sync()
}
this.connection.end()
this.connection.stream.once('end', cb)
}
Cursor.prototype.close = function(cb) {
this.connection.close({type: 'P'})
this.connection.sync()
this.state = 'done'
if(cb) {
this.connection.once('closeComplete', function() {
cb()
})
}
}
Cursor.prototype.read = function(rows, cb) {
var self = this
if(this.state == 'idle') {
return this._getRows(rows, cb)
}
if(this.state == 'busy' || this.state == 'initialized') {
return this._queue.push([rows, cb])
}
if(this.state == 'error') {
return cb(this._error)
}
if(this.state == 'done') {
return cb(null, [])
}
else {
throw new Error("Unknown state: " + this.state)
}
}
module.exports = Cursor