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编辑当前文件:/home/freeclou/app.optimyar.com/backend/node_modules/react-dnd/dist/esm/common/DndProvider.js

function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _nonIterableRest(); }

function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance"); }

function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }

import * as React from 'react';
import { memo } from 'react';
import { DndContext, createDndContext } from './DndContext';
var refCount = 0;
/**
 * A React component that provides the React-DnD context
 */

export var DndProvider = memo(function (_ref) {
  var children = _ref.children,
      props = _objectWithoutProperties(_ref, ["children"]);

var _getDndContextValue = getDndContextValue(props),
      _getDndContextValue2 = _slicedToArray(_getDndContextValue, 2),
      manager = _getDndContextValue2[0],
      isGlobalInstance = _getDndContextValue2[1]; // memoized from props

/**
   * If the global context was used to store the DND context
   * then where theres no more references to it we should
   * clean it up to avoid memory leaks
   */

React.useEffect(function () {
    if (isGlobalInstance) {
      refCount++;
    }

return function () {
      if (isGlobalInstance) {
        refCount--;

if (refCount === 0) {
          var context = getGlobalContext();
          context[instanceSymbol] = null;
        }
      }
    };
  }, []);
  return React.createElement(DndContext.Provider, {
    value: manager
  }, children);
});
DndProvider.displayName = 'DndProvider';

function getDndContextValue(props) {
  if ('manager' in props) {
    var _manager = {
      dragDropManager: props.manager
    };
    return [_manager, false];
  }

var manager = createSingletonDndContext(props.backend, props.context, props.options, props.debugMode);
  var isGlobalInstance = !props.context;
  return [manager, isGlobalInstance];
}

var instanceSymbol = Symbol.for('__REACT_DND_CONTEXT_INSTANCE__');

function createSingletonDndContext(backend) {
  var context = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : getGlobalContext();
  var options = arguments.length > 2 ? arguments[2] : undefined;
  var debugMode = arguments.length > 3 ? arguments[3] : undefined;
  var ctx = context;

if (!ctx[instanceSymbol]) {
    ctx[instanceSymbol] = createDndContext(backend, context, options, debugMode);
  }

return ctx[instanceSymbol];
}

function getGlobalContext() {
  return typeof global !== 'undefined' ? global : window;
}