/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @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() {
'use strict';
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() {
'use strict';
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() {
'use strict';
return /** @type {goog.fs.FileReader.ReadyState} */ (this.reader_.readyState);
};
/**
* @return {*} The result of the file read.
*/
goog.fs.FileReader.prototype.getResult = function() {
'use strict';
return this.reader_.result;
};
/**
* @return {goog.fs.Error} The error encountered while reading, if any.
*/
goog.fs.FileReader.prototype.getError = function() {
'use strict';
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) {
'use strict';
this.dispatchEvent(new goog.fs.ProgressEvent(event, this));
};
/** @override */
goog.fs.FileReader.prototype.disposeInternal = function() {
'use strict';
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) {
'use strict';
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) {
'use strict';
const reader = new goog.fs.FileReader();
const 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) {
'use strict';
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) {
'use strict';
const reader = new goog.fs.FileReader();
const 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) {
'use strict';
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) {
'use strict';
const reader = new goog.fs.FileReader();
const 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) {
'use strict';
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) {
'use strict';
const reader = new goog.fs.FileReader();
const 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) {
'use strict';
const deferred = new goog.async.Deferred();
reader.listen(
goog.fs.FileReader.EventType.LOAD_END, goog.partial(function(d, r, e) {
'use strict';
const result = r.getResult();
const error = r.getError();
if (result != null && !error) {
d.callback(result);
} else {
d.errback(error);
}
r.dispose();
}, deferred, reader));
return deferred;
};
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