@graffy/common/esm/ops/sieve.js

Common libraries that used by various Graffy modules.

import _extends from "@babel/runtime/helpers/esm/extends";

function _createForOfIteratorHelperLoose(o, allowArrayLike) { var it; if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) { if (Array.isArray(o) || (it = _unsupportedIterableToArray(o)) || allowArrayLike && o && typeof o.length === "number") { if (it) o = it; var i = 0; return function () { if (i >= o.length) return { done: true }; return { done: false, value: o[i++] }; }; } throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); } it = o[Symbol.iterator](); return it.next.bind(it); }

function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(o); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }

function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }

import { isBranch, isRange, findFirst, findLast } from '../node';
import { keyAfter, keyBefore } from './step';
export default function sieve(current, changes, result) {
  if (result === void 0) {
    result = [];
  }

  var index = 0;

  for (var _iterator = _createForOfIteratorHelperLoose(changes), _step; !(_step = _iterator()).done;) {
    var change = _step.value;
    index = isRange(change) ? insertRange(current, change, result, index) : insertNode(current, change, result, index);
  }

  return result;
}
export function insertRange(current, change, result, start) {
  if (start === void 0) {
    start = 0;
  }

  var key = change.key,
      end = change.end;
  var keyIx = findFirst(current, key, start);
  var endIx = findLast(current, end, keyIx);

  if (keyIx === endIx && !(current[keyIx] && current[keyIx].key <= key && current[keyIx].end >= end)) {
    // This range does not overlap with any existing data. Ignore it.
    return keyIx;
  }

  var appliedChange = [];
  var currentKey = change.key;

  for (var i = keyIx; i < endIx; i++) {
    var node = current[i]; // We treat a negative version as a non-existent node
    // as this is a hack used by subscribe.

    if (isRange(node) && node.version >= 0) {
      if (node.key > currentKey) {
        appliedChange.push({
          key: currentKey,
          end: keyBefore(node.key),
          version: change.version
        });
      }

      currentKey = keyAfter(node.end);
    } else {
      if (getNewerChange(node, change)) {
        appliedChange.push({
          key: currentKey,
          end: keyBefore(node.key),
          version: change.version
        });
        currentKey = keyAfter(node.key);
      }
    }

    if (currentKey >= change.end) {
      break;
    }
  }

  if (currentKey <= change.end) {
    appliedChange.push({
      key: currentKey,
      end: change.end,
      version: change.version
    });
  }

  if (appliedChange.length) result.push.apply(result, appliedChange); // If current contains nodes that are newer than this range, keep them.
  // We do this by merging them back into insertions first.

  var insertions = [change];

  for (var _i = keyIx; _i < endIx; _i++) {
    var _node = current[_i];

    if (isRange(_node)) {
      // console.log('Sieve Range-Range', debug(change), debug(node));
      insertions.push.apply(insertions, mergeRanges(insertions.pop(), _node));
    } else {
      // console.log('Sieve Change-Node', debug(change), debug(node));
      insertNode(insertions, _node, [], insertions.length - 1);
    }
  } // console.log('Sieve:insertions', debug(insertions));


  current.splice.apply(current, [keyIx, endIx - keyIx].concat(insertions));
  return keyIx + insertions.length;
}

function mergeRanges(base, node) {
  // assertVersion(node, base.version);
  // eslint-disable-next-line no-param-reassign
  if (node.version < base.version) {
    var _ref = [base, node];
    node = _ref[0];
    base = _ref[1];
  } // Ensure node is newer than base


  return [base.key < node.key && _extends({}, base, {
    end: keyBefore(node.key)
  }), node, base.end > node.end && _extends({}, base, {
    key: keyAfter(node.end)
  })].filter(Boolean);
}

export function insertNode(current, change, result, start) {
  if (start === void 0) {
    start = 0;
  }

  var key = change.key;
  var index = findFirst(current, key, start);
  var node = current[index];

  if (node && node.key <= key) {
    // This change overlaps with something that exists.
    return isRange(node) ? insertNodeIntoRange(current, index, change, result) : updateNode(current, index, change, result);
  } else {
    // This change does not overlap with any existing knowledge. Skip it
    // current.splice(index, 0, change);
    return index;
  }
}

function insertNodeIntoRange(current, index, change, result) {
  var key = change.key;
  var range = current[index];
  var newChange = getNewerChange(change, range);
  var newNode = getNewerNode(change, range);
  if (!newChange) return;
  result.push(newChange);
  var insertions = [range.key < key && _extends({}, range, {
    end: keyBefore(key)
  }), newNode, range.end > key && _extends({}, range, {
    key: keyAfter(key)
  })].filter(Boolean);
  current.splice.apply(current, [index, 1].concat(insertions));
  return index + insertions.length;
}

function updateNode(current, index, change, result) {
  var node = current[index];

  if (isBranch(change) && isBranch(node)) {
    // Both are branches: Recursively merge children.
    var nextResult = [];
    node.version = change.version;
    sieve(node.children, change.children, nextResult);
    if (nextResult.length) result.push(_extends({}, change, {
      children: nextResult
    }));
  } else if (isBranch(node)) {
    // Current node is a branch but the change is a leaf; if the branch
    // has newer children, ignore the change and keep only those children;
    // Otherwise, discard the branch and keep the change.
    var newNode = getNewerNode(node, change);
    current[index] = newNode || change;
    if (!newNode) result.push(change); // TODO: In the case of partial removal, what should result be?
  } else {
    // Current node is a leaf. Replace with the change if it is newer.
    var newChange = getNewerChange(change, node);

    var _newNode = getNewerNode(change, node);

    if (_newNode) current[index] = _newNode; // console.log(current);

    if (newChange && (change.value !== node.value || !isPathEqual(change.path, node.path))) {
      result.push(newChange);
    }
  }

  return index + 1;
}

function isPathEqual(first, second) {
  if (!first && !second) return true;
  if (!first || !second) return false;
  if (first.length !== second.length) return false;

  for (var i = 0; i < first.length; i++) {
    if (first[i] !== second[i]) return false;
  }

  return true;
}

function getNewerNode(node, base) {
  if (isBranch(node)) {
    var emptyNode = {
      key: '',
      end: "\uFFFF",
      version: base.version
    };
    var children = [emptyNode];
    sieve(children, node.children);
    return children.length === 1 && children[0] === emptyNode ? null : _extends({}, node, {
      children: children
    });
  } else {
    // assertVersion(node, version);
    return node.version >= base.version ? node : null;
  }
}

function getNewerChange(node, base) {
  if (isBranch(node)) {
    var children = node.children.filter(function (child) {
      return getNewerChange(child, base);
    });
    return children.length && _extends({}, node, {
      children: children
    });
  } else {
    // assertVersion(node, version);
    return node.version >= base.version ? node : null;
  }
} // function assertVersion(node, version) {
//   // if (node.version === version) {
//   //   throw Error('merge.version_collision ' + [node.key, version].join(' '));
//   // }
// }