152 lines
3.1 KiB
JavaScript
152 lines
3.1 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule DocumentSelectionState
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* @typechecks
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*/
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'use strict';
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var mixInEventEmitter = require('mixInEventEmitter');
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/**
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* DocumentSelectionState is responsible for maintaining selection information
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* for a document.
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*
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* It is intended for use by AbstractTextEditor-based components for
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* identifying the appropriate start/end positions to modify the
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* DocumentContent, and for programatically setting browser selection when
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* components re-render.
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*/
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class DocumentSelectionState {
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/**
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* @param {number} anchor
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* @param {number} focus
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*/
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constructor(anchor, focus) {
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this._anchorOffset = anchor;
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this._focusOffset = focus;
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this._hasFocus = false;
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}
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/**
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* Apply an update to the state. If either offset value has changed,
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* set the values and emit the `change` event. Otherwise no-op.
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*
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* @param {number} anchor
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* @param {number} focus
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*/
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update(anchor, focus) {
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if (this._anchorOffset !== anchor || this._focusOffset !== focus) {
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this._anchorOffset = anchor;
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this._focusOffset = focus;
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this.emit('update');
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}
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}
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/**
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* Given a max text length, constrain our selection offsets to ensure
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* that the selection remains strictly within the text range.
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*
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* @param {number} maxLength
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*/
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constrainLength(maxLength) {
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this.update(
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Math.min(this._anchorOffset, maxLength),
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Math.min(this._focusOffset, maxLength)
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);
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}
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focus() {
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if (!this._hasFocus) {
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this._hasFocus = true;
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this.emit('focus');
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}
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}
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blur() {
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if (this._hasFocus) {
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this._hasFocus = false;
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this.emit('blur');
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}
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}
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/**
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* @return {boolean}
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*/
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hasFocus() {
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return this._hasFocus;
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}
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/**
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* @return {boolean}
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*/
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isCollapsed() {
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return this._anchorOffset === this._focusOffset;
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}
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/**
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* @return {boolean}
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*/
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isBackward() {
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return this._anchorOffset > this._focusOffset;
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}
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/**
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* @return {?number}
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*/
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getAnchorOffset() {
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return this._hasFocus ? this._anchorOffset : null;
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}
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/**
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* @return {?number}
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*/
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getFocusOffset() {
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return this._hasFocus ? this._focusOffset : null;
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}
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/**
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* @return {?number}
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*/
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getStartOffset() {
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return (
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this._hasFocus ? Math.min(this._anchorOffset, this._focusOffset) : null
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);
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}
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/**
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* @return {?number}
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*/
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getEndOffset() {
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return (
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this._hasFocus ? Math.max(this._anchorOffset, this._focusOffset) : null
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);
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}
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/**
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* @param {number} start
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* @param {number} end
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* @return {boolean}
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*/
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overlaps(start, end) {
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return (
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this.hasFocus() &&
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this.getStartOffset() <= end && start <= this.getEndOffset()
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);
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}
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}
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mixInEventEmitter(DocumentSelectionState, {
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'blur': true,
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'focus': true,
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'update': true
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});
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module.exports = DocumentSelectionState;
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