126 lines
3.9 KiB
JavaScript
126 lines
3.9 KiB
JavaScript
"use strict";
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//---------------------------------------------------------------------------
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// @syndicate-lang/core, an implementation of Syndicate dataspaces for JS.
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// Copyright (C) 2016-2018 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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//---------------------------------------------------------------------------
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// Property-based "dataflow"
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var Immutable = require("immutable");
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var MapSet = require("./mapset.js");
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function Graph() {
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this.edgesForward = Immutable.Map();
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this.edgesReverse = Immutable.Map();
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this.damagedNodes = Immutable.Set();
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this.currentSubjectId = null;
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}
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Graph.prototype.withSubject = function (subjectId, f) {
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var oldSubjectId = this.currentSubjectId;
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this.currentSubjectId = subjectId;
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var result;
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try {
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result = f();
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} catch (e) {
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this.currentSubjectId = oldSubjectId;
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throw e;
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}
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this.currentSubjectId = oldSubjectId;
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return result;
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};
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Graph.prototype.recordObservation = function (objectId) {
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if (this.currentSubjectId) {
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this.edgesForward = MapSet.add(this.edgesForward, objectId, this.currentSubjectId);
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this.edgesReverse = MapSet.add(this.edgesReverse, this.currentSubjectId, objectId);
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}
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};
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Graph.prototype.recordDamage = function (objectId) {
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this.damagedNodes = this.damagedNodes.add(objectId);
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};
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Graph.prototype.forgetSubject = function (subjectId) {
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var self = this;
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var subjectObjects = self.edgesReverse.get(subjectId) || Immutable.Set();
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self.edgesReverse = self.edgesReverse.remove(subjectId);
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subjectObjects.forEach(function (objectId) {
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self.edgesForward = MapSet.remove(self.edgesForward, objectId, subjectId);
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});
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};
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Graph.prototype.repairDamage = function (repairNode) {
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var self = this;
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var repairedThisRound = Immutable.Set();
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while (true) {
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var workSet = self.damagedNodes;
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self.damagedNodes = Immutable.Set();
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var alreadyDamaged = workSet.intersect(repairedThisRound);
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if (!alreadyDamaged.isEmpty()) {
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console.warn('Cyclic dependencies involving', alreadyDamaged);
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}
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workSet = workSet.subtract(repairedThisRound);
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repairedThisRound = repairedThisRound.union(workSet);
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if (workSet.isEmpty()) break;
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workSet.forEach(function (objectId) {
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var subjects = self.edgesForward.get(objectId) || Immutable.Set();
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subjects.forEach(function (subjectId) {
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self.forgetSubject(subjectId);
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self.withSubject(subjectId, function () {
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repairNode(subjectId);
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});
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});
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});
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}
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};
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Graph.prototype.defineObservableProperty = function (obj, prop, value, maybeOptions) {
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var graph = this;
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var options = maybeOptions === void 0 ? {} : maybeOptions;
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var objectId = options.objectId || '__' + prop;
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Object.defineProperty(obj, prop, {
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configurable: true,
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enumerable: true,
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get: function () {
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graph.recordObservation(objectId);
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return value;
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},
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set: function (newValue) {
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if (!options.noopGuard || !options.noopGuard(value, newValue)) {
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graph.recordDamage(objectId);
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value = newValue;
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}
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}
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});
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graph.recordDamage(objectId);
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return objectId;
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};
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Graph.newScope = function (o) {
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function O() {}
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O.prototype = o;
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return new O();
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};
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///////////////////////////////////////////////////////////////////////////
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module.exports.Graph = Graph;
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