| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| part of html; |
| |
| /** |
| * Internal class that does the actual calculations to determine keyCode and |
| * charCode for keydown, keypress, and keyup events for all browsers. |
| */ |
| class _KeyboardEventHandler extends EventStreamProvider<KeyEvent> { |
| // This code inspired by Closure's KeyHandling library. |
| // http://closure-library.googlecode.com/svn/docs/closure_goog_events_keyhandler.js.source.html |
| |
| /** |
| * The set of keys that have been pressed down without seeing their |
| * corresponding keyup event. |
| */ |
| final List<KeyboardEvent> _keyDownList = <KeyboardEvent>[]; |
| |
| /** The type of KeyEvent we are tracking (keyup, keydown, keypress). */ |
| final String _type; |
| |
| /** The element we are watching for events to happen on. */ |
| final EventTarget _target; |
| |
| // The distance to shift from upper case alphabet Roman letters to lower case. |
| static final int _ROMAN_ALPHABET_OFFSET = "a".codeUnits[0] - "A".codeUnits[0]; |
| |
| /** Controller to produce KeyEvents for the stream. */ |
| final StreamController _controller = new StreamController(sync: true); |
| |
| static const _EVENT_TYPE = 'KeyEvent'; |
| |
| /** |
| * An enumeration of key identifiers currently part of the W3C draft for DOM3 |
| * and their mappings to keyCodes. |
| * http://www.w3.org/TR/DOM-Level-3-Events/keyset.html#KeySet-Set |
| */ |
| static const Map<String, int> _keyIdentifier = const { |
| 'Up': KeyCode.UP, |
| 'Down': KeyCode.DOWN, |
| 'Left': KeyCode.LEFT, |
| 'Right': KeyCode.RIGHT, |
| 'Enter': KeyCode.ENTER, |
| 'F1': KeyCode.F1, |
| 'F2': KeyCode.F2, |
| 'F3': KeyCode.F3, |
| 'F4': KeyCode.F4, |
| 'F5': KeyCode.F5, |
| 'F6': KeyCode.F6, |
| 'F7': KeyCode.F7, |
| 'F8': KeyCode.F8, |
| 'F9': KeyCode.F9, |
| 'F10': KeyCode.F10, |
| 'F11': KeyCode.F11, |
| 'F12': KeyCode.F12, |
| 'U+007F': KeyCode.DELETE, |
| 'Home': KeyCode.HOME, |
| 'End': KeyCode.END, |
| 'PageUp': KeyCode.PAGE_UP, |
| 'PageDown': KeyCode.PAGE_DOWN, |
| 'Insert': KeyCode.INSERT |
| }; |
| |
| /** Return a stream for KeyEvents for the specified target. */ |
| Stream<KeyEvent> forTarget(EventTarget e, {bool useCapture: false}) { |
| return new _KeyboardEventHandler.initializeAllEventListeners( |
| _type, e).stream; |
| } |
| |
| /** |
| * Accessor to the stream associated with a particular KeyboardEvent |
| * EventTarget. |
| * |
| * [forTarget] must be called to initialize this stream to listen to a |
| * particular EventTarget. |
| */ |
| Stream<KeyEvent> get stream { |
| if(_target != null) { |
| return _controller.stream; |
| } else { |
| throw new StateError("Not initialized. Call forTarget to access a stream " |
| "initialized with a particular EventTarget."); |
| } |
| } |
| |
| /** |
| * General constructor, performs basic initialization for our improved |
| * KeyboardEvent controller. |
| */ |
| _KeyboardEventHandler(this._type) : |
| _target = null, super(_EVENT_TYPE) { |
| } |
| |
| /** |
| * Hook up all event listeners under the covers so we can estimate keycodes |
| * and charcodes when they are not provided. |
| */ |
| _KeyboardEventHandler.initializeAllEventListeners(this._type, this._target) : |
| super(_EVENT_TYPE) { |
| Element.keyDownEvent.forTarget(_target, useCapture: true).listen( |
| processKeyDown); |
| Element.keyPressEvent.forTarget(_target, useCapture: true).listen( |
| processKeyPress); |
| Element.keyUpEvent.forTarget(_target, useCapture: true).listen( |
| processKeyUp); |
| } |
| |
| /** |
| * Notify all callback listeners that a KeyEvent of the relevant type has |
| * occurred. |
| */ |
| bool _dispatch(KeyEvent event) { |
| if (event.type == _type) |
| _controller.add(event); |
| } |
| |
| /** Determine if caps lock is one of the currently depressed keys. */ |
| bool get _capsLockOn => |
| _keyDownList.any((var element) => element.keyCode == KeyCode.CAPS_LOCK); |
| |
| /** |
| * Given the previously recorded keydown key codes, see if we can determine |
| * the keycode of this keypress [event]. (Generally browsers only provide |
| * charCode information for keypress events, but with a little |
| * reverse-engineering, we can also determine the keyCode.) Returns |
| * KeyCode.UNKNOWN if the keycode could not be determined. |
| */ |
| int _determineKeyCodeForKeypress(KeyboardEvent event) { |
| // Note: This function is a work in progress. We'll expand this function |
| // once we get more information about other keyboards. |
| for (var prevEvent in _keyDownList) { |
| if (prevEvent._shadowCharCode == event.charCode) { |
| return prevEvent.keyCode; |
| } |
| if ((event.shiftKey || _capsLockOn) && event.charCode >= "A".codeUnits[0] |
| && event.charCode <= "Z".codeUnits[0] && event.charCode + |
| _ROMAN_ALPHABET_OFFSET == prevEvent._shadowCharCode) { |
| return prevEvent.keyCode; |
| } |
| } |
| return KeyCode.UNKNOWN; |
| } |
| |
| /** |
| * Given the charater code returned from a keyDown [event], try to ascertain |
| * and return the corresponding charCode for the character that was pressed. |
| * This information is not shown to the user, but used to help polyfill |
| * keypress events. |
| */ |
| int _findCharCodeKeyDown(KeyboardEvent event) { |
| if (event.keyLocation == 3) { // Numpad keys. |
| switch (event.keyCode) { |
| case KeyCode.NUM_ZERO: |
| // Even though this function returns _charCodes_, for some cases the |
| // KeyCode == the charCode we want, in which case we use the keycode |
| // constant for readability. |
| return KeyCode.ZERO; |
| case KeyCode.NUM_ONE: |
| return KeyCode.ONE; |
| case KeyCode.NUM_TWO: |
| return KeyCode.TWO; |
| case KeyCode.NUM_THREE: |
| return KeyCode.THREE; |
| case KeyCode.NUM_FOUR: |
| return KeyCode.FOUR; |
| case KeyCode.NUM_FIVE: |
| return KeyCode.FIVE; |
| case KeyCode.NUM_SIX: |
| return KeyCode.SIX; |
| case KeyCode.NUM_SEVEN: |
| return KeyCode.SEVEN; |
| case KeyCode.NUM_EIGHT: |
| return KeyCode.EIGHT; |
| case KeyCode.NUM_NINE: |
| return KeyCode.NINE; |
| case KeyCode.NUM_MULTIPLY: |
| return 42; // Char code for * |
| case KeyCode.NUM_PLUS: |
| return 43; // + |
| case KeyCode.NUM_MINUS: |
| return 45; // - |
| case KeyCode.NUM_PERIOD: |
| return 46; // . |
| case KeyCode.NUM_DIVISION: |
| return 47; // / |
| } |
| } else if (event.keyCode >= 65 && event.keyCode <= 90) { |
| // Set the "char code" for key down as the lower case letter. Again, this |
| // will not show up for the user, but will be helpful in estimating |
| // keyCode locations and other information during the keyPress event. |
| return event.keyCode + _ROMAN_ALPHABET_OFFSET; |
| } |
| switch(event.keyCode) { |
| case KeyCode.SEMICOLON: |
| return KeyCode.FF_SEMICOLON; |
| case KeyCode.EQUALS: |
| return KeyCode.FF_EQUALS; |
| case KeyCode.COMMA: |
| return 44; // Ascii value for , |
| case KeyCode.DASH: |
| return 45; // - |
| case KeyCode.PERIOD: |
| return 46; // . |
| case KeyCode.SLASH: |
| return 47; // / |
| case KeyCode.APOSTROPHE: |
| return 96; // ` |
| case KeyCode.OPEN_SQUARE_BRACKET: |
| return 91; // [ |
| case KeyCode.BACKSLASH: |
| return 92; // \ |
| case KeyCode.CLOSE_SQUARE_BRACKET: |
| return 93; // ] |
| case KeyCode.SINGLE_QUOTE: |
| return 39; // ' |
| } |
| return event.keyCode; |
| } |
| |
| /** |
| * Returns true if the key fires a keypress event in the current browser. |
| */ |
| bool _firesKeyPressEvent(KeyEvent event) { |
| if (!Device.isIE && !Device.isWebKit) { |
| return true; |
| } |
| |
| if (Device.userAgent.contains('Mac') && event.altKey) { |
| return KeyCode.isCharacterKey(event.keyCode); |
| } |
| |
| // Alt but not AltGr which is represented as Alt+Ctrl. |
| if (event.altKey && !event.ctrlKey) { |
| return false; |
| } |
| |
| // Saves Ctrl or Alt + key for IE and WebKit, which won't fire keypress. |
| if (!event.shiftKey && |
| (_keyDownList.last.keyCode == KeyCode.CTRL || |
| _keyDownList.last.keyCode == KeyCode.ALT || |
| Device.userAgent.contains('Mac') && |
| _keyDownList.last.keyCode == KeyCode.META)) { |
| return false; |
| } |
| |
| // Some keys with Ctrl/Shift do not issue keypress in WebKit. |
| if (Device.isWebKit && event.ctrlKey && event.shiftKey && ( |
| event.keyCode == KeyCode.BACKSLASH || |
| event.keyCode == KeyCode.OPEN_SQUARE_BRACKET || |
| event.keyCode == KeyCode.CLOSE_SQUARE_BRACKET || |
| event.keyCode == KeyCode.TILDE || |
| event.keyCode == KeyCode.SEMICOLON || event.keyCode == KeyCode.DASH || |
| event.keyCode == KeyCode.EQUALS || event.keyCode == KeyCode.COMMA || |
| event.keyCode == KeyCode.PERIOD || event.keyCode == KeyCode.SLASH || |
| event.keyCode == KeyCode.APOSTROPHE || |
| event.keyCode == KeyCode.SINGLE_QUOTE)) { |
| return false; |
| } |
| |
| switch (event.keyCode) { |
| case KeyCode.ENTER: |
| // IE9 does not fire keypress on ENTER. |
| return !Device.isIE; |
| case KeyCode.ESC: |
| return !Device.isWebKit; |
| } |
| |
| return KeyCode.isCharacterKey(event.keyCode); |
| } |
| |
| /** |
| * Normalize the keycodes to the IE KeyCodes (this is what Chrome, IE, and |
| * Opera all use). |
| */ |
| int _normalizeKeyCodes(KeyboardEvent event) { |
| // Note: This may change once we get input about non-US keyboards. |
| if (Device.isFirefox) { |
| switch(event.keyCode) { |
| case KeyCode.FF_EQUALS: |
| return KeyCode.EQUALS; |
| case KeyCode.FF_SEMICOLON: |
| return KeyCode.SEMICOLON; |
| case KeyCode.MAC_FF_META: |
| return KeyCode.META; |
| case KeyCode.WIN_KEY_FF_LINUX: |
| return KeyCode.WIN_KEY; |
| } |
| } |
| return event.keyCode; |
| } |
| |
| /** Handle keydown events. */ |
| void processKeyDown(KeyboardEvent e) { |
| // Ctrl-Tab and Alt-Tab can cause the focus to be moved to another window |
| // before we've caught a key-up event. If the last-key was one of these |
| // we reset the state. |
| if (_keyDownList.length > 0 && |
| (_keyDownList.last.keyCode == KeyCode.CTRL && !e.ctrlKey || |
| _keyDownList.last.keyCode == KeyCode.ALT && !e.altKey || |
| Device.userAgent.contains('Mac') && |
| _keyDownList.last.keyCode == KeyCode.META && !e.metaKey)) { |
| _keyDownList.clear(); |
| } |
| |
| var event = new KeyEvent(e); |
| event._shadowKeyCode = _normalizeKeyCodes(event); |
| // Technically a "keydown" event doesn't have a charCode. This is |
| // calculated nonetheless to provide us with more information in giving |
| // as much information as possible on keypress about keycode and also |
| // charCode. |
| event._shadowCharCode = _findCharCodeKeyDown(event); |
| if (_keyDownList.length > 0 && event.keyCode != _keyDownList.last.keyCode && |
| !_firesKeyPressEvent(event)) { |
| // Some browsers have quirks not firing keypress events where all other |
| // browsers do. This makes them more consistent. |
| processKeyPress(e); |
| } |
| _keyDownList.add(event); |
| _dispatch(event); |
| } |
| |
| /** Handle keypress events. */ |
| void processKeyPress(KeyboardEvent event) { |
| var e = new KeyEvent(event); |
| // IE reports the character code in the keyCode field for keypress events. |
| // There are two exceptions however, Enter and Escape. |
| if (Device.isIE) { |
| if (e.keyCode == KeyCode.ENTER || e.keyCode == KeyCode.ESC) { |
| e._shadowCharCode = 0; |
| } else { |
| e._shadowCharCode = e.keyCode; |
| } |
| } else if (Device.isOpera) { |
| // Opera reports the character code in the keyCode field. |
| e._shadowCharCode = KeyCode.isCharacterKey(e.keyCode) ? e.keyCode : 0; |
| } |
| // Now we guestimate about what the keycode is that was actually |
| // pressed, given previous keydown information. |
| e._shadowKeyCode = _determineKeyCodeForKeypress(e); |
| |
| // Correct the key value for certain browser-specific quirks. |
| if (e._shadowKeyIdentifier != null && |
| _keyIdentifier.containsKey(e._shadowKeyIdentifier)) { |
| // This is needed for Safari Windows because it currently doesn't give a |
| // keyCode/which for non printable keys. |
| e._shadowKeyCode = _keyIdentifier[e._shadowKeyIdentifier]; |
| } |
| e._shadowAltKey = _keyDownList.any((var element) => element.altKey); |
| _dispatch(e); |
| } |
| |
| /** Handle keyup events. */ |
| void processKeyUp(KeyboardEvent event) { |
| var e = new KeyEvent(event); |
| KeyboardEvent toRemove = null; |
| for (var key in _keyDownList) { |
| if (key.keyCode == e.keyCode) { |
| toRemove = key; |
| } |
| } |
| if (toRemove != null) { |
| _keyDownList.removeWhere((element) => element == toRemove); |
| } else if (_keyDownList.length > 0) { |
| // This happens when we've reached some international keyboard case we |
| // haven't accounted for or we haven't correctly eliminated all browser |
| // inconsistencies. Filing bugs on when this is reached is welcome! |
| _keyDownList.removeLast(); |
| } |
| _dispatch(e); |
| } |
| } |
| |
| |
| /** |
| * Records KeyboardEvents that occur on a particular element, and provides a |
| * stream of outgoing KeyEvents with cross-browser consistent keyCode and |
| * charCode values despite the fact that a multitude of browsers that have |
| * varying keyboard default behavior. |
| * |
| * Example usage: |
| * |
| * KeyboardEventStream.onKeyDown(document.body).listen( |
| * keydownHandlerTest); |
| * |
| * This class is very much a work in progress, and we'd love to get information |
| * on how we can make this class work with as many international keyboards as |
| * possible. Bugs welcome! |
| */ |
| class KeyboardEventStream { |
| |
| /** Named constructor to produce a stream for onKeyPress events. */ |
| static Stream<KeyEvent> onKeyPress(EventTarget target) => |
| new _KeyboardEventHandler('keypress').forTarget(target); |
| |
| /** Named constructor to produce a stream for onKeyUp events. */ |
| static Stream<KeyEvent> onKeyUp(EventTarget target) => |
| new _KeyboardEventHandler('keyup').forTarget(target); |
| |
| /** Named constructor to produce a stream for onKeyDown events. */ |
| static Stream<KeyEvent> onKeyDown(EventTarget target) => |
| new _KeyboardEventHandler('keydown').forTarget(target); |
| } |
