/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Detects images dragged and dropped on to the window.
*/
goog.provide('goog.ui.DragDropDetector');
goog.provide('goog.ui.DragDropDetector.EventType');
goog.provide('goog.ui.DragDropDetector.ImageDropEvent');
goog.provide('goog.ui.DragDropDetector.LinkDropEvent');
goog.require('goog.dom');
goog.require('goog.dom.InputType');
goog.require('goog.dom.TagName');
goog.require('goog.events.Event');
goog.require('goog.events.EventHandler');
goog.require('goog.events.EventTarget');
goog.require('goog.events.EventType');
goog.require('goog.math.Coordinate');
goog.require('goog.string');
goog.require('goog.style');
goog.require('goog.userAgent');
goog.requireType('goog.events.BrowserEvent');
/**
* Creates a new drag and drop detector.
* @param {string=} opt_filePath The URL of the page to use for the detector.
* It should contain the same contents as dragdropdetector_target.html in
* the demos directory.
* @constructor
* @extends {goog.events.EventTarget}
* @final
*/
goog.ui.DragDropDetector = function(opt_filePath) {
'use strict';
goog.ui.DragDropDetector.base(this, 'constructor');
var iframe = goog.dom.createDom(goog.dom.TagName.IFRAME, {'frameborder': 0});
// In Firefox, we do all drop detection with an IFRAME. In IE, we only use
// the IFRAME to capture copied, non-linked images. (When we don't need it,
// we put a text INPUT before it and push it off screen.)
iframe.className = goog.userAgent.IE ?
goog.getCssName(
goog.ui.DragDropDetector.BASE_CSS_NAME_, 'ie-editable-iframe') :
goog.getCssName(
goog.ui.DragDropDetector.BASE_CSS_NAME_, 'w3c-editable-iframe');
iframe.src = opt_filePath || goog.ui.DragDropDetector.DEFAULT_FILE_PATH_;
this.element_ = /** @type {!HTMLIFrameElement} */ (iframe);
this.handler_ = new goog.events.EventHandler(this);
this.handler_.listen(iframe, goog.events.EventType.LOAD, this.initIframe_);
if (goog.userAgent.IE) {
// In IE, we have to bounce between an INPUT for catching links and an
// IFRAME for catching images.
this.textInput_ = goog.dom.createDom(goog.dom.TagName.INPUT, {
'type': goog.dom.InputType.TEXT,
'className':
goog.getCssName(goog.ui.DragDropDetector.BASE_CSS_NAME_, 'ie-input')
});
this.root_ = goog.dom.createDom(
goog.dom.TagName.DIV,
goog.getCssName(goog.ui.DragDropDetector.BASE_CSS_NAME_, 'ie-div'),
this.textInput_, iframe);
} else {
this.root_ = iframe;
}
document.body.appendChild(this.root_);
};
goog.inherits(goog.ui.DragDropDetector, goog.events.EventTarget);
/**
* Drag and drop event types.
* @enum {string}
*/
goog.ui.DragDropDetector.EventType = {
IMAGE_DROPPED: 'onimagedrop',
LINK_DROPPED: 'onlinkdrop'
};
/**
* Browser specific drop event type.
* @type {string}
* @private
*/
goog.ui.DragDropDetector.DROP_EVENT_TYPE_ =
goog.userAgent.IE ? goog.events.EventType.DROP : 'dragdrop';
/**
* Initial value for clientX and clientY indicating that the location has
* never been updated.
*/
goog.ui.DragDropDetector.INIT_POSITION = -10000;
/**
* Prefix for all CSS names.
* @type {string}
* @private
*/
goog.ui.DragDropDetector.BASE_CSS_NAME_ = goog.getCssName('goog-dragdrop');
/**
* @desc Message shown to users to inform them that they can't drag and drop
* local files.
*/
goog.ui.DragDropDetector.MSG_DRAG_DROP_LOCAL_FILE_ERROR = goog.getMsg(
'It is not possible to drag ' +
'and drop image files at this time.\nPlease drag an image from your web ' +
'browser.');
/**
* @desc Message shown to users trying to drag and drop protected images from
* Flickr, etc.
*/
goog.ui.DragDropDetector.MSG_DRAG_DROP_PROTECTED_FILE_ERROR = goog.getMsg(
'The image you are ' +
'trying to drag has been blocked by the hosting site.');
/**
* A map of special case information for URLs that cannot be dropped. Each
* entry is of the form:
* regex: url regex
* message: user visible message about this special case
* @type {Array<{regex: RegExp, message: string}>}
* @private
*/
goog.ui.DragDropDetector.SPECIAL_CASE_URLS_ = [
{
regex: /^file:\/\/\//,
message: goog.ui.DragDropDetector.MSG_DRAG_DROP_LOCAL_FILE_ERROR
},
{
regex: /flickr(.*)spaceball.gif$/,
message: goog.ui.DragDropDetector.MSG_DRAG_DROP_PROTECTED_FILE_ERROR
}
];
/**
* Regex that matches anything that looks kind of like a URL. It matches
* nonspacechars://nonspacechars
* @type {RegExp}
* @private
*/
goog.ui.DragDropDetector.URL_LIKE_REGEX_ = /^\S+:\/\/\S*$/;
/**
* Path to the dragdrop.html file.
* @type {string}
* @private
*/
goog.ui.DragDropDetector.DEFAULT_FILE_PATH_ = 'dragdropdetector_target.html';
/**
* Our event handler object.
* @type {goog.events.EventHandler<!goog.ui.DragDropDetector>}
* @private
*/
goog.ui.DragDropDetector.prototype.handler_;
/**
* The root element (the IFRAME on most browsers, the DIV on IE).
* @type {Element}
* @private
*/
goog.ui.DragDropDetector.prototype.root_;
/**
* The text INPUT element used to detect link drops on IE. null on Firefox.
* @type {Element}
* @private
*/
goog.ui.DragDropDetector.prototype.textInput_;
/**
* The iframe element.
* @type {HTMLIFrameElement}
* @private
*/
goog.ui.DragDropDetector.prototype.element_;
/**
* The iframe's window, null if the iframe hasn't loaded yet.
* @type {?Window}
* @private
*/
goog.ui.DragDropDetector.prototype.window_ = null;
/**
* The iframe's document, null if the iframe hasn't loaded yet.
* @type {?Document}
* @private
*/
goog.ui.DragDropDetector.prototype.document_ = null;
/**
* The iframe's body, null if the iframe hasn't loaded yet.
* @type {?HTMLBodyElement}
* @private
*/
goog.ui.DragDropDetector.prototype.body_ = null;
/**
* Whether we are in "screen cover" mode in which the iframe or div is
* covering the entire screen.
* @type {boolean}
* @private
*/
goog.ui.DragDropDetector.prototype.isCoveringScreen_ = false;
/**
* The last position of the mouse while dragging.
* @type {?goog.math.Coordinate}
* @private
*/
goog.ui.DragDropDetector.prototype.mousePosition_ = null;
/**
* Initialize the iframe after it has loaded.
* @private
*/
goog.ui.DragDropDetector.prototype.initIframe_ = function() {
'use strict';
// Set up a holder for position data.
this.mousePosition_ = new goog.math.Coordinate(
goog.ui.DragDropDetector.INIT_POSITION,
goog.ui.DragDropDetector.INIT_POSITION);
// Set up pointers to the important parts of the IFrame.
this.window_ = this.element_.contentWindow;
this.document_ = this.window_.document;
this.body_ = this.document_.body;
if (goog.userAgent.GECKO) {
this.document_.designMode = 'on';
} else if (!goog.userAgent.IE) {
// Bug 1667110
// In IE, we only set the IFrame body as content-editable when we bring it
// into view at the top of the page. Otherwise it may take focus when the
// page is loaded, scrolling the user far offscreen.
// Note that this isn't easily unit-testable, since it depends on a
// browser-specific behavior with content-editable areas.
this.body_.contentEditable = true;
}
this.handler_.listen(
document.body, goog.events.EventType.DRAGENTER, this.coverScreen_);
if (goog.userAgent.IE) {
// IE only events.
// Set up events on the IFrame.
this.handler_
.listen(
this.body_,
[goog.events.EventType.DRAGENTER, goog.events.EventType.DRAGOVER],
goog.ui.DragDropDetector.enforceCopyEffect_)
.listen(this.body_, goog.events.EventType.MOUSEOUT, this.switchToInput_)
.listen(
this.body_, goog.events.EventType.DRAGLEAVE, this.uncoverScreen_)
.listen(
this.body_, goog.ui.DragDropDetector.DROP_EVENT_TYPE_,
function(e) {
'use strict';
this.trackMouse_(e);
// The drop event occurs before the content is added to the
// iframe. We setTimeout so that handleNodeInserted_ is called
// after the content is in the document.
goog.global.setTimeout(
goog.bind(this.handleNodeInserted_, this, e), 0);
return true;
})
.
// Set up events on the DIV.
listen(
this.root_,
[goog.events.EventType.DRAGENTER, goog.events.EventType.DRAGOVER],
this.handleNewDrag_)
.listen(
this.root_,
[goog.events.EventType.MOUSEMOVE, goog.events.EventType.KEYPRESS],
this.uncoverScreen_)
.
// Set up events on the text INPUT.
listen(
this.textInput_, goog.events.EventType.DRAGOVER,
goog.events.Event.preventDefault)
.listen(
this.textInput_, goog.ui.DragDropDetector.DROP_EVENT_TYPE_,
this.handleInputDrop_);
} else {
// W3C events.
this.handler_
.listen(
this.body_, goog.ui.DragDropDetector.DROP_EVENT_TYPE_,
function(e) {
'use strict';
this.trackMouse_(e);
this.uncoverScreen_();
})
.listen(
this.body_,
[goog.events.EventType.MOUSEMOVE, goog.events.EventType.KEYPRESS],
this.uncoverScreen_)
// Detect content insertion.
.listen(this.document_, 'DOMNodeInserted', this.handleNodeInserted_);
}
};
/**
* Enforce that anything dragged over the IFRAME is copied in to it, rather
* than making it navigate to a different URL.
* @param {goog.events.BrowserEvent} e The event to enforce copying on.
* @private
*/
goog.ui.DragDropDetector.enforceCopyEffect_ = function(e) {
'use strict';
var event = e.getBrowserEvent();
// This function is only called on IE.
if (event.dataTransfer.dropEffect.toLowerCase() != 'copy') {
event.dataTransfer.dropEffect = 'copy';
}
};
/**
* Cover the screen with the iframe.
* @param {goog.events.BrowserEvent} e The event that caused this function call.
* @private
*/
goog.ui.DragDropDetector.prototype.coverScreen_ = function(e) {
'use strict';
// Don't do anything if the drop effect is 'none' and we are in IE.
// It is set to 'none' in cases like dragging text inside a text area.
if (goog.userAgent.IE &&
e.getBrowserEvent().dataTransfer.dropEffect == 'none') {
return;
}
if (!this.isCoveringScreen_) {
this.isCoveringScreen_ = true;
if (goog.userAgent.IE) {
goog.style.setStyle(this.root_, 'top', '0');
this.body_.contentEditable = true;
this.switchToInput_(e);
} else {
goog.style.setStyle(this.root_, 'height', '5000px');
}
}
};
/**
* Uncover the screen.
* @private
*/
goog.ui.DragDropDetector.prototype.uncoverScreen_ = function() {
'use strict';
if (this.isCoveringScreen_) {
this.isCoveringScreen_ = false;
if (goog.userAgent.IE) {
this.body_.contentEditable = false;
goog.style.setStyle(this.root_, 'top', '-5000px');
} else {
goog.style.setStyle(this.root_, 'height', '10px');
}
}
};
/**
* Re-insert the INPUT into the DIV. Does nothing when the DIV is off screen.
* @param {goog.events.BrowserEvent} e The event that caused this function call.
* @private
*/
goog.ui.DragDropDetector.prototype.switchToInput_ = function(e) {
'use strict';
// This is only called on IE.
if (this.isCoveringScreen_) {
goog.style.setElementShown(this.textInput_, true);
}
};
/**
* Remove the text INPUT so the IFRAME is showing. Does nothing when the DIV is
* off screen.
* @param {goog.events.BrowserEvent} e The event that caused this function call.
* @private
*/
goog.ui.DragDropDetector.prototype.switchToIframe_ = function(e) {
'use strict';
// This is only called on IE.
if (this.isCoveringScreen_) {
goog.style.setElementShown(this.textInput_, false);
}
};
/**
* Handle a new drag event.
* @param {goog.events.BrowserEvent} e The event object.
* @return {boolean|undefined} Returns false in IE to cancel the event.
* @private
*/
goog.ui.DragDropDetector.prototype.handleNewDrag_ = function(e) {
'use strict';
var event = e.getBrowserEvent();
// This is only called on IE.
if (event.dataTransfer.dropEffect == 'link') {
this.switchToInput_(e);
e.preventDefault();
return false;
}
// Things that aren't links can be placed in the contentEditable iframe.
this.switchToIframe_(e);
// No need to return true since for events return true is the same as no
// return.
};
/**
* Handle mouse tracking.
* @param {goog.events.BrowserEvent} e The event object.
* @private
*/
goog.ui.DragDropDetector.prototype.trackMouse_ = function(e) {
'use strict';
this.mousePosition_.x = e.clientX;
this.mousePosition_.y = e.clientY;
// Check if the event is coming from within the iframe.
if (goog.dom.getOwnerDocument(/** @type {Node} */ (e.target)) != document) {
var iframePosition = goog.style.getClientPosition(this.element_);
this.mousePosition_.x += iframePosition.x;
this.mousePosition_.y += iframePosition.y;
}
};
/**
* Handle a drop on the IE text INPUT.
* @param {goog.events.BrowserEvent} e The event object.
* @private
*/
goog.ui.DragDropDetector.prototype.handleInputDrop_ = function(e) {
'use strict';
this.dispatchEvent(new goog.ui.DragDropDetector.LinkDropEvent(
e.getBrowserEvent().dataTransfer.getData('Text')));
this.uncoverScreen_();
e.preventDefault();
};
/**
* Clear the contents of the iframe.
* @private
*/
goog.ui.DragDropDetector.prototype.clearContents_ = function() {
'use strict';
if (goog.userAgent.WEBKIT) {
// Since this is called on a mutation event for the nodes we are going to
// clear, calling this right away crashes some versions of WebKit. Wait
// until the events are finished.
goog.global.setTimeout(goog.bind(function() {
'use strict';
goog.dom.setTextContent(this, '');
}, this.body_), 0);
} else {
this.document_.execCommand('selectAll', false, null);
this.document_.execCommand('delete', false, null);
this.document_.execCommand('selectAll', false, null);
}
};
/**
* Event handler called when the content of the iframe changes.
* @param {goog.events.BrowserEvent} e The event that caused this function call.
* @private
*/
goog.ui.DragDropDetector.prototype.handleNodeInserted_ = function(e) {
'use strict';
var uri;
if (this.body_.innerHTML.indexOf('<') == -1) {
// If the document contains no tags (i.e. is just text), try it out.
uri = goog.string.trim(goog.dom.getTextContent(this.body_));
// See if it looks kind of like a url.
if (!uri.match(goog.ui.DragDropDetector.URL_LIKE_REGEX_)) {
uri = null;
}
}
if (!uri) {
var imgs = goog.dom.getElementsByTagName(goog.dom.TagName.IMG, this.body_);
if (imgs && imgs.length) {
// TODO(robbyw): Grab all the images, instead of just the first.
var img = imgs[0];
uri = img.src;
}
}
if (uri) {
var specialCases = goog.ui.DragDropDetector.SPECIAL_CASE_URLS_;
var len = specialCases.length;
for (var i = 0; i < len; i++) {
var specialCase = specialCases[i];
if (uri.match(specialCase.regex)) {
alert(specialCase.message);
break;
}
}
// If no special cases matched, add the image.
if (i == len) {
this.dispatchEvent(
new goog.ui.DragDropDetector.ImageDropEvent(
uri, this.mousePosition_));
return;
}
}
var links = goog.dom.getElementsByTagName(goog.dom.TagName.A, this.body_);
if (links) {
for (i = 0, len = links.length; i < len; i++) {
this.dispatchEvent(
new goog.ui.DragDropDetector.LinkDropEvent(links[i].href));
}
}
this.clearContents_();
this.uncoverScreen_();
};
/** @override */
goog.ui.DragDropDetector.prototype.disposeInternal = function() {
'use strict';
goog.ui.DragDropDetector.base(this, 'disposeInternal');
this.handler_.dispose();
this.handler_ = null;
};
/**
* Creates a new image drop event object.
* @param {string} url The url of the dropped image.
* @param {goog.math.Coordinate} position The screen position where the drop
* occurred.
* @constructor
* @extends {goog.events.Event}
* @final
*/
goog.ui.DragDropDetector.ImageDropEvent = function(url, position) {
'use strict';
goog.ui.DragDropDetector.ImageDropEvent.base(
this, 'constructor', goog.ui.DragDropDetector.EventType.IMAGE_DROPPED);
/**
* The url of the image that was dropped.
* @type {string}
* @private
*/
this.url_ = url;
/**
* The screen position where the drop occurred.
* @type {goog.math.Coordinate}
* @private
*/
this.position_ = position;
};
goog.inherits(goog.ui.DragDropDetector.ImageDropEvent, goog.events.Event);
/**
* @return {string} The url of the image that was dropped.
*/
goog.ui.DragDropDetector.ImageDropEvent.prototype.getUrl = function() {
'use strict';
return this.url_;
};
/**
* @return {goog.math.Coordinate} The screen position where the drop occurred.
* This may be have x and y of goog.ui.DragDropDetector.INIT_POSITION,
* indicating the drop position is unknown.
*/
goog.ui.DragDropDetector.ImageDropEvent.prototype.getPosition = function() {
'use strict';
return this.position_;
};
/**
* Creates a new link drop event object.
* @param {string} url The url of the dropped link.
* @constructor
* @extends {goog.events.Event}
* @final
*/
goog.ui.DragDropDetector.LinkDropEvent = function(url) {
'use strict';
goog.ui.DragDropDetector.LinkDropEvent.base(
this, 'constructor', goog.ui.DragDropDetector.EventType.LINK_DROPPED);
/**
* The url of the link that was dropped.
* @type {string}
* @private
*/
this.url_ = url;
};
goog.inherits(goog.ui.DragDropDetector.LinkDropEvent, goog.events.Event);
/**
* @return {string} The url of the link that was dropped.
*/
goog.ui.DragDropDetector.LinkDropEvent.prototype.getUrl = function() {
'use strict';
return this.url_;
};
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