1 files changed, 151 insertions, 0 deletions
diff --git a/www/external/screwdriver.js b/www/external/screwdriver.js
new file mode 100644
index 00000000..c6733776
--- /dev/null
+++ b/www/external/screwdriver.js
@@ -0,0 +1,151 @@
+;(function() {
+
+	if(typeof Blob === 'undefined')
+		return console.warn('Screw-FileReader is only meant to work in those' +
+	'engine who already has some basic support for blob')
+
+	var blob = Blob.prototype
+	var fullStreamSupport = false
+	var basicStreamSupport = false
+	var fetchTransform = false
+	var URL = window.URL || window.webkitURL
+
+	function promisify(obj) {
+		return new Promise(function(resolve, reject) {
+			obj.onload =
+			obj.onerror = function(evt) {
+				obj.onload =
+				obj.onerror = null
+
+				evt.type === 'load'
+					? resolve(obj.result || obj)
+					: reject(obj.error)
+			}
+		})
+	}
+
+	function toImage(url) {
+		var img = new Image
+		img.src = url
+		return promisify(img)
+	}
+
+	try {
+		new ReadableStream({})
+		basicStreamSupport = true
+	} catch (e) {}
+
+	try {
+		new ReadableStream({type: 'bytes'})
+		fullStreamSupport = true
+	} catch (e) {}
+
+	try {
+		(new Response(new Blob)).getReader()
+		fetchTransform = true
+	} catch (e) {}
+
+	if(!blob.arrayBuffer) {
+		blob.arrayBuffer = function arrayBuffer() {
+			var fr = new FileReader
+			fr.readAsArrayBuffer(this)
+			return promisify(fr)
+		}
+	}
+
+	if(!blob.text) {
+		blob.text = function text() {
+			var fr = new FileReader
+			fr.readAsText(this)
+			return promisify(fr)
+		}
+	}
+
+	if(!blob.dataURL) {
+		blob.dataURL = function dataURL() {
+			var fr = new FileReader
+			fr.readAsDataURL(this)
+			return promisify(fr)
+		}
+	}
+
+	if(!blob.url) {
+		blob.url = function url() {
+			return URL ? URL.createObjectURL(this) : null
+		}
+	}
+
+	if(!blob.json) {
+		blob.json = function json() {
+			return this.text().then(JSON.parse)
+		}
+	}
+
+	if(!blob.image) {
+		blob.image = function image() {
+			return Promise.resolve(this.url() || this.dataURL()).then(toImage)
+		}
+	}
+
+	if(!blob.stream) {
+		blob.stream =
+
+		fullStreamSupport ? function stream() {
+			var position = 0
+			var blob = this
+
+			return new ReadableStream({
+				type: 'bytes',
+				autoAllocateChunkSize: 524288,
+
+				pull: function (controller) {
+					var v = controller.byobRequest.view
+					var chunk = blob.slice(position, position + v.byteLength)
+					return chunk.arrayBuffer()
+					.then(function (buffer) {
+						let uint8array = new Uint8Array(buffer)
+						let bytesRead = uint8array.byteLength
+
+						position += bytesRead
+						v.set(uint8array)
+							controller.byobRequest.respond(bytesRead)
+
+						if(position >= blob.size)
+							controller.close()
+					})
+				}
+			})
+		}:
+
+		// basic stream support
+		basicStreamSupport ? function stream(blob){
+			var position = 0
+			var blob = this
+
+			return new ReadableStream({
+				pull: function (controller) {
+					var chunk = blob.slice(position, position + 524288)
+
+					return chunk.arrayBuffer().then(function (buffer) {
+						position += buffer.byteLength
+						let uint8array = new Uint8Array(buffer)
+						controller.enqueue(uint8array)
+
+						if(position == blob.size)
+							controller.close()
+					})
+				}
+			})
+		}:
+
+		// fetchTransform
+		fetchTransform ? function stream() {
+			return (new Response(this)).body
+		}:
+
+		function stream() {
+			throw new Error('Include https://github.com/creatorrr/web-streams-polyfill')
+		}
+	}
+
+}());