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b46a4fe286
* Google changed from an Inc to an LLC. This happened back in 2017 but we didn’t notice. Officially we should update files from Inc to LLC when they are changed as part of regular edits, but this is a nightmare to remember for the next decade. * Remove project description/titles from licenses This is no longer part of Google’s header requirements. Our existing descriptions were useless (“Visual Blocks Editor”) or grossly obselete (“Visual Blocks Language”). * License no longer requires URL. * Fix license regexps.
98 lines
3.5 KiB
JavaScript
98 lines
3.5 KiB
JavaScript
/**
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* @license
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* Copyright 2019 Google LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @fileoverview Fields can be created based on a JSON definition. This file
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* contains methods for registering those JSON definitions, and building the
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* fields based on JSON.
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* @author bekawestberg@gmail.com (Beka Westberg)
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*/
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'use strict';
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goog.provide('Blockly.fieldRegistry');
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/**
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* The set of all registered fields, keyed by field type as used in the JSON
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* definition of a block.
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* @type {!Object<string, !{fromJson: Function}>}
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* @private
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*/
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Blockly.fieldRegistry.typeMap_ = {};
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/**
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* Registers a field type.
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* Blockly.fieldRegistry.fromJson uses this registry to
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* find the appropriate field type.
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* @param {string} type The field type name as used in the JSON definition.
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* @param {!{fromJson: Function}} fieldClass The field class containing a
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* fromJson function that can construct an instance of the field.
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* @throws {Error} if the type name is empty, the field is already
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* registered, or the fieldClass is not an object containing a fromJson
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* function.
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*/
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Blockly.fieldRegistry.register = function(type, fieldClass) {
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if ((typeof type != 'string') || (type.trim() == '')) {
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throw Error('Invalid field type "' + type + '". The type must be a' +
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' non-empty string.');
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}
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if (Blockly.fieldRegistry.typeMap_[type]) {
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throw Error('Error: Field "' + type + '" is already registered.');
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}
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if (!fieldClass || (typeof fieldClass.fromJson != 'function')) {
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throw Error('Field "' + fieldClass + '" must have a fromJson function');
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}
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type = type.toLowerCase();
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Blockly.fieldRegistry.typeMap_[type] = fieldClass;
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};
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/**
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* Unregisters the field registered with the given type.
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* @param {string} type The field type name as used in the JSON definition.
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*/
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Blockly.fieldRegistry.unregister = function(type) {
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if (Blockly.fieldRegistry.typeMap_[type]) {
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Blockly.fieldRegistry.typeMap_[type] = undefined;
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} else {
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console.warn('No field mapping for type "' + type +
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'" found to unregister');
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}
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};
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/**
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* Construct a Field from a JSON arg object.
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* Finds the appropriate registered field by the type name as registered using
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* Blockly.fieldRegistry.register.
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* @param {!Object} options A JSON object with a type and options specific
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* to the field type.
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* @return {Blockly.Field} The new field instance or null if a field wasn't
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* found with the given type name
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* @package
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*/
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Blockly.fieldRegistry.fromJson = function(options) {
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var type = options['type'].toLowerCase();
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var fieldClass = Blockly.fieldRegistry.typeMap_[type];
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if (!fieldClass) {
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console.warn('Blockly could not create a field of type ' + options['type'] +
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'. The field is probably not being registered. This could be because' +
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' the file is not loaded, the field does not register itself (Issue' +
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' #1584), or the registration is not being reached.');
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return null;
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}
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return fieldClass.fromJson(options);
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};
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