| // Copyright 2011 The Closure Library Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS-IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| /** |
| * @fileoverview A wrapper for the HTML5 FileReader object. |
| * |
| */ |
| |
| goog.provide('goog.fs.FileReader'); |
| goog.provide('goog.fs.FileReader.EventType'); |
| goog.provide('goog.fs.FileReader.ReadyState'); |
| |
| goog.require('goog.async.Deferred'); |
| goog.require('goog.events.EventTarget'); |
| goog.require('goog.fs.Error'); |
| goog.require('goog.fs.ProgressEvent'); |
| |
| |
| |
| /** |
| * An object for monitoring the reading of files. This emits ProgressEvents of |
| * the types listed in {@link goog.fs.FileReader.EventType}. |
| * |
| * @constructor |
| * @extends {goog.events.EventTarget} |
| * @final |
| */ |
| goog.fs.FileReader = function() { |
| goog.fs.FileReader.base(this, 'constructor'); |
| |
| /** |
| * The underlying FileReader object. |
| * |
| * @type {!FileReader} |
| * @private |
| */ |
| this.reader_ = new FileReader(); |
| |
| this.reader_.onloadstart = goog.bind(this.dispatchProgressEvent_, this); |
| this.reader_.onprogress = goog.bind(this.dispatchProgressEvent_, this); |
| this.reader_.onload = goog.bind(this.dispatchProgressEvent_, this); |
| this.reader_.onabort = goog.bind(this.dispatchProgressEvent_, this); |
| this.reader_.onerror = goog.bind(this.dispatchProgressEvent_, this); |
| this.reader_.onloadend = goog.bind(this.dispatchProgressEvent_, this); |
| }; |
| goog.inherits(goog.fs.FileReader, goog.events.EventTarget); |
| |
| |
| /** |
| * Possible states for a FileReader. |
| * |
| * @enum {number} |
| */ |
| goog.fs.FileReader.ReadyState = { |
| /** |
| * The object has been constructed, but there is no pending read. |
| */ |
| INIT: 0, |
| /** |
| * Data is being read. |
| */ |
| LOADING: 1, |
| /** |
| * The data has been read from the file, the read was aborted, or an error |
| * occurred. |
| */ |
| DONE: 2 |
| }; |
| |
| |
| /** |
| * Events emitted by a FileReader. |
| * |
| * @enum {string} |
| */ |
| goog.fs.FileReader.EventType = { |
| /** |
| * Emitted when the reading begins. readyState will be LOADING. |
| */ |
| LOAD_START: 'loadstart', |
| /** |
| * Emitted when progress has been made in reading the file. readyState will be |
| * LOADING. |
| */ |
| PROGRESS: 'progress', |
| /** |
| * Emitted when the data has been successfully read. readyState will be |
| * LOADING. |
| */ |
| LOAD: 'load', |
| /** |
| * Emitted when the reading has been aborted. readyState will be LOADING. |
| */ |
| ABORT: 'abort', |
| /** |
| * Emitted when an error is encountered or the reading has been aborted. |
| * readyState will be LOADING. |
| */ |
| ERROR: 'error', |
| /** |
| * Emitted when the reading is finished, whether successfully or not. |
| * readyState will be DONE. |
| */ |
| LOAD_END: 'loadend' |
| }; |
| |
| |
| /** |
| * Abort the reading of the file. |
| */ |
| goog.fs.FileReader.prototype.abort = function() { |
| try { |
| this.reader_.abort(); |
| } catch (e) { |
| throw new goog.fs.Error(e, 'aborting read'); |
| } |
| }; |
| |
| |
| /** |
| * @return {goog.fs.FileReader.ReadyState} The current state of the FileReader. |
| */ |
| goog.fs.FileReader.prototype.getReadyState = function() { |
| return /** @type {goog.fs.FileReader.ReadyState} */ (this.reader_.readyState); |
| }; |
| |
| |
| /** |
| * @return {*} The result of the file read. |
| */ |
| goog.fs.FileReader.prototype.getResult = function() { |
| return this.reader_.result; |
| }; |
| |
| |
| /** |
| * @return {goog.fs.Error} The error encountered while reading, if any. |
| */ |
| goog.fs.FileReader.prototype.getError = function() { |
| return this.reader_.error && |
| new goog.fs.Error(this.reader_.error, 'reading file'); |
| }; |
| |
| |
| /** |
| * Wrap a progress event emitted by the underlying file reader and re-emit it. |
| * |
| * @param {!ProgressEvent} event The underlying event. |
| * @private |
| */ |
| goog.fs.FileReader.prototype.dispatchProgressEvent_ = function(event) { |
| this.dispatchEvent(new goog.fs.ProgressEvent(event, this)); |
| }; |
| |
| |
| /** @override */ |
| goog.fs.FileReader.prototype.disposeInternal = function() { |
| goog.fs.FileReader.base(this, 'disposeInternal'); |
| delete this.reader_; |
| }; |
| |
| |
| /** |
| * Starts reading a blob as a binary string. |
| * @param {!Blob} blob The blob to read. |
| */ |
| goog.fs.FileReader.prototype.readAsBinaryString = function(blob) { |
| this.reader_.readAsBinaryString(blob); |
| }; |
| |
| |
| /** |
| * Reads a blob as a binary string. |
| * @param {!Blob} blob The blob to read. |
| * @return {!goog.async.Deferred} The deferred Blob contents as a binary string. |
| * If an error occurs, the errback is called with a {@link goog.fs.Error}. |
| */ |
| goog.fs.FileReader.readAsBinaryString = function(blob) { |
| var reader = new goog.fs.FileReader(); |
| var d = goog.fs.FileReader.createDeferred_(reader); |
| reader.readAsBinaryString(blob); |
| return d; |
| }; |
| |
| |
| /** |
| * Starts reading a blob as an array buffer. |
| * @param {!Blob} blob The blob to read. |
| */ |
| goog.fs.FileReader.prototype.readAsArrayBuffer = function(blob) { |
| this.reader_.readAsArrayBuffer(blob); |
| }; |
| |
| |
| /** |
| * Reads a blob as an array buffer. |
| * @param {!Blob} blob The blob to read. |
| * @return {!goog.async.Deferred} The deferred Blob contents as an array buffer. |
| * If an error occurs, the errback is called with a {@link goog.fs.Error}. |
| */ |
| goog.fs.FileReader.readAsArrayBuffer = function(blob) { |
| var reader = new goog.fs.FileReader(); |
| var d = goog.fs.FileReader.createDeferred_(reader); |
| reader.readAsArrayBuffer(blob); |
| return d; |
| }; |
| |
| |
| /** |
| * Starts reading a blob as text. |
| * @param {!Blob} blob The blob to read. |
| * @param {string=} opt_encoding The name of the encoding to use. |
| */ |
| goog.fs.FileReader.prototype.readAsText = function(blob, opt_encoding) { |
| this.reader_.readAsText(blob, opt_encoding); |
| }; |
| |
| |
| /** |
| * Reads a blob as text. |
| * @param {!Blob} blob The blob to read. |
| * @param {string=} opt_encoding The name of the encoding to use. |
| * @return {!goog.async.Deferred} The deferred Blob contents as text. |
| * If an error occurs, the errback is called with a {@link goog.fs.Error}. |
| */ |
| goog.fs.FileReader.readAsText = function(blob, opt_encoding) { |
| var reader = new goog.fs.FileReader(); |
| var d = goog.fs.FileReader.createDeferred_(reader); |
| reader.readAsText(blob, opt_encoding); |
| return d; |
| }; |
| |
| |
| /** |
| * Starts reading a blob as a data URL. |
| * @param {!Blob} blob The blob to read. |
| */ |
| goog.fs.FileReader.prototype.readAsDataUrl = function(blob) { |
| this.reader_.readAsDataURL(blob); |
| }; |
| |
| |
| /** |
| * Reads a blob as a data URL. |
| * @param {!Blob} blob The blob to read. |
| * @return {!goog.async.Deferred} The deferred Blob contents as a data URL. |
| * If an error occurs, the errback is called with a {@link goog.fs.Error}. |
| */ |
| goog.fs.FileReader.readAsDataUrl = function(blob) { |
| var reader = new goog.fs.FileReader(); |
| var d = goog.fs.FileReader.createDeferred_(reader); |
| reader.readAsDataUrl(blob); |
| return d; |
| }; |
| |
| |
| /** |
| * Creates a new deferred object for the results of a read method. |
| * @param {goog.fs.FileReader} reader The reader to create a deferred for. |
| * @return {!goog.async.Deferred} The deferred results. |
| * @private |
| */ |
| goog.fs.FileReader.createDeferred_ = function(reader) { |
| var deferred = new goog.async.Deferred(); |
| reader.listen(goog.fs.FileReader.EventType.LOAD_END, |
| goog.partial(function(d, r, e) { |
| var result = r.getResult(); |
| var error = r.getError(); |
| if (result != null && !error) { |
| d.callback(result); |
| } else { |
| d.errback(error); |
| } |
| r.dispose(); |
| }, deferred, reader)); |
| return deferred; |
| }; |