Initial commit

2013-10-28 17:31:11 -05:00
commit d3d648a623
7 changed files with 284 additions and 0 deletions
@@ -0,0 +1,105 @@
+module.exports = function(txt) {
+  return new CopyStreamQuery(txt)
+}
+
+var Transform = require('stream').Transform
+var util = require('util')
+
+var CopyStreamQuery = function(text) {
+  Transform.call(this)
+  this.text = text
+  this._listeners = null
+  this._copyOutResponse = null
+  this.rowsRead = 0
+}
+
+util.inherits(CopyStreamQuery, Transform)
+
+CopyStreamQuery.prototype.submit = function(connection) {
+  console.log('submitting')
+  connection.query(this.text)
+  this.connection = connection
+  this._listeners = connection.stream.listeners('data')
+  connection.stream.removeAllListeners('data')
+  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.connection.stream.removeAllListeners('data')
+  var self = this
+  this._listeners.forEach(function(listener) {
+    self.connection.stream.on('data', listener)
+  })
+}
+
+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.connection.stream.unshift(chunk)
+      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
+    if(messageCode == code.c) {
+      this._detach()
+      this.connection.stream.unshift(chunk.slice(offset + 5))
+      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.rowsRead++
+      this.push(slice)
+    } 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.handleCommandComplete = function() {
+}
+
+CopyStreamQuery.prototype.handleReadyForQuery = function() {
+}