node-pg-copy-streams/copy-to.js
Chris Kinsman 9d197a91e1 Add resume
2015-12-16 16:43:22 -08:00

104 lines
2.5 KiB
JavaScript

module.exports = function(txt, options) {
return new CopyStreamQuery(txt, options)
}
var Transform = require('stream').Transform
var util = require('util')
var CopyStreamQuery = function(text, options) {
Transform.call(this, options)
this.text = text
this._copyOutResponse = null
this.rowCount = 0
}
util.inherits(CopyStreamQuery, Transform)
var eventTypes = ['close', 'data', 'end', 'error']
CopyStreamQuery.prototype.submit = function(connection) {
connection.query(this.text)
this.connection = connection
this.connection.removeAllListeners('copyData')
connection.stream.pipe(this)
}
var code = {
E: 69, //Error
H: 72, //CopyOutResponse
d: 0x64, //CopyData
c: 0x63 //CopyDone
}
CopyStreamQuery.prototype._detach = function() {
this.connection.stream.unpipe(this)
// Unpipe can drop us out of flowing mode
this.connection.stream.resume()
}
CopyStreamQuery.prototype._transform = function(chunk, enc, cb) {
var offset = 0
if(this._remainder && chunk) {
chunk = Buffer.concat([this._remainder, chunk])
}
if(!this._copyOutResponse) {
this._copyOutResponse = true
if(chunk[0] == code.E) {
this._detach()
this.push(null)
return cb();
}
if(chunk[0] != code.H) {
this.emit('error', new Error('Expected copy out response'))
}
var length = chunk.readUInt32BE(1)
offset = 1
offset += length
}
while((chunk.length - offset) > 5) {
var messageCode = chunk[offset]
//complete or error
if(messageCode == code.c || messageCode == code.E) {
this._detach()
this.push(null)
return cb();
}
//something bad happened
if(messageCode != code.d) {
return this.emit('error', new Error('expected "d" (copydata message)'))
}
var length = chunk.readUInt32BE(offset + 1) - 4 //subtract length of UInt32
//can we read the next row?
if(chunk.length > (offset + length + 5)) {
offset += 5
var slice = chunk.slice(offset, offset + length)
offset += length
this.push(slice)
this.rowCount++
} else {
break;
}
}
if(chunk.length - offset) {
var slice = chunk.slice(offset)
this._remainder = slice
} else {
this._remainder = false
}
cb()
}
CopyStreamQuery.prototype.handleError = function(e) {
this.emit('error', e)
}
CopyStreamQuery.prototype.handleCopyData = function(chunk) {
}
CopyStreamQuery.prototype.handleCommandComplete = function() {
}
CopyStreamQuery.prototype.handleReadyForQuery = function() {
}