mirror of
https://github.com/google/blockly.git
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112 lines
3.9 KiB
JavaScript
112 lines
3.9 KiB
JavaScript
/**
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* AccessibleBlockly
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*
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* Copyright 2016 Google Inc.
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* https://developers.google.com/blockly/
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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 Angular2 Service for handling the mechanics of how blocks
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* get connected to each other.
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* @author sll@google.com (Sean Lip)
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*/
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blocklyApp.BlockConnectionService = ng.core.Class({
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constructor: [
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blocklyApp.NotificationsService, blocklyApp.AudioService,
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function(_notificationsService, _audioService) {
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this.notificationsService = _notificationsService;
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this.audioService = _audioService;
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// When a user "adds a link" to a block, the connection representing this
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// link is stored here.
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this.markedConnection_ = null;
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}],
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findCompatibleConnection_: function(block) {
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// Locates and returns a connection on the given block that is compatible
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// with the marked connection, if one exists. Returns null if no such
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// connection exists.
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// Note: this currently ignores input connections on the given block, since
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// one doesn't usually mark an output connection and attach a block to it.
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if (!this.markedConnection_ ||
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!this.markedConnection_.getSourceBlock().workspace) {
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return null;
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}
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var desiredType = Blockly.OPPOSITE_TYPE[this.markedConnection_.type];
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var potentialConnection = (
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desiredType == Blockly.OUTPUT_VALUE ? block.outputConnection :
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desiredType == Blockly.PREVIOUS_STATEMENT ? block.previousConnection :
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desiredType == Blockly.NEXT_STATEMENT ? block.nextConnection :
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null);
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if (potentialConnection &&
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potentialConnection.checkType_(this.markedConnection_)) {
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return potentialConnection;
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} else {
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return null;
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}
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},
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isAnyConnectionMarked: function() {
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return Boolean(this.markedConnection_);
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},
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getMarkedConnectionSourceBlock: function() {
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return this.markedConnection_ ?
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this.markedConnection_.getSourceBlock() : null;
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},
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canBeAttachedToMarkedConnection: function(block) {
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return Boolean(this.findCompatibleConnection_(block));
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},
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canBeMovedToMarkedConnection: function(block) {
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if (!this.markedConnection_) {
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return false;
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}
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// It should not be possible to move any ancestor of the block containing
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// the marked connection to the marked connection.
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var ancestorBlock = this.getMarkedConnectionSourceBlock();
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while (ancestorBlock) {
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if (ancestorBlock.id == block.id) {
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return false;
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}
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ancestorBlock = ancestorBlock.getParent();
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}
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return this.canBeAttachedToMarkedConnection(block);
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},
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markConnection: function(connection) {
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this.markedConnection_ = connection;
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this.notificationsService.speak(Blockly.Msg.ADDED_LINK_MSG);
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},
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attachToMarkedConnection: function(block) {
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var xml = Blockly.Xml.blockToDom(block);
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var reconstitutedBlock = Blockly.Xml.domToBlock(blocklyApp.workspace, xml);
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var connection = this.findCompatibleConnection_(reconstitutedBlock);
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if (connection) {
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this.markedConnection_.connect(connection);
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this.markedConnection_ = null;
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this.audioService.playConnectSound();
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return reconstitutedBlock.id;
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} else {
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// We throw an error here, because we expect any UI controls that would
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// result in a non-connection to be disabled or hidden.
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throw Error(
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'Unable to connect block to marked connection. This should not ' +
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'happen.');
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}
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}
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});
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