558 lines
16 KiB
JavaScript
558 lines
16 KiB
JavaScript
var Route = require("./route.js");
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///////////////////////////////////////////////////////////////////////////
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// TODO: trigger-guards as per minimart
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/*---------------------------------------------------------------------------*/
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/* Events and Actions */
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var __ = Route.__;
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var _$ = Route._$;
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function sub(pattern, metaLevel, level) {
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return Route.simpleGestalt(false, pattern, metaLevel, level);
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}
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function pub(pattern, metaLevel, level) {
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return Route.simpleGestalt(true, pattern, metaLevel, level);
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}
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function spawn(behavior, initialGestalts) {
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return { type: "spawn",
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behavior: behavior,
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initialGestalt: Route.gestaltUnion(initialGestalts || []) };
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}
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function updateRoutes(gestalts) {
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return { type: "routes", gestalt: Route.gestaltUnion(gestalts) };
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}
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function pendingRoutingUpdate(aggregate, affectedSubgestalt, knownTarget) {
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return { type: "pendingRoutingUpdate",
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aggregate: aggregate,
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affectedSubgestalt: affectedSubgestalt,
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knownTarget: knownTarget };
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}
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function sendMessage(m, metaLevel, isFeedback) {
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return { type: "message",
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metaLevel: (metaLevel === undefined) ? 0 : metaLevel,
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message: m,
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isFeedback: (isFeedback === undefined) ? false : isFeedback };
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}
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function shutdownWorld() {
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return { type: "shutdownWorld" };
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}
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/*---------------------------------------------------------------------------*/
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/* Configurations */
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function World(bootFn) {
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this.alive = true;
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this.eventQueue = [];
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this.runnablePids = {};
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this.partialGestalt = Route.emptyGestalt; // Only gestalt from local processes
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this.fullGestalt = Route.emptyGestalt ;; // partialGestalt unioned with downwardGestalt
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this.processTable = {};
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this.tombstones = {};
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this.downwardGestalt = Route.emptyGestalt;
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this.processActions = [];
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this.asChild(-1, bootFn, true);
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}
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/* Class state / methods */
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World.nextPid = 0;
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World.stack = [];
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World.current = function () {
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return World.stack[World.stack.length - 1][0];
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};
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World.activePid = function () {
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return World.stack[World.stack.length - 1][1];
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};
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World.send = function (m, metaLevel, isFeedback) {
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World.current().enqueueAction(World.activePid(), sendMessage(m, metaLevel, isFeedback));
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};
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World.updateRoutes = function (gestalts) {
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World.current().enqueueAction(World.activePid(), updateRoutes(gestalts));
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};
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World.spawn = function (behavior, initialGestalts) {
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World.current().enqueueAction(World.activePid(), spawn(behavior, initialGestalts));
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};
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World.exit = function (exn) {
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World.current().kill(World.activePid(), exn);
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};
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World.shutdownWorld = function () {
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World.current().enqueueAction(World.activePid(), shutdownWorld());
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};
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World.withWorldStack = function (stack, f) {
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var oldStack = World.stack;
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World.stack = stack;
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var result = null;
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try {
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result = f();
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} catch (e) {
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World.stack = oldStack;
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throw e;
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}
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World.stack = oldStack;
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return result;
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};
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World.wrap = function (f) {
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var savedStack = World.stack.slice();
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return function () {
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var actuals = arguments;
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return World.withWorldStack(savedStack, function () {
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var result = World.current().asChild(World.activePid(), function () {
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return f.apply(null, actuals);
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});
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for (var i = World.stack.length - 1; i >= 0; i--) {
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World.stack[i][0].markPidRunnable(World.stack[i][1]);
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}
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return result;
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});
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};
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};
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/* Instance methods */
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World.prototype.enqueueAction = function (pid, action) {
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this.processActions.push([pid, action]);
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};
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// The code is written to maintain the runnablePids set carefully, to
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// ensure we can locally decide whether we're inert or not without
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// having to search the whole deep process tree.
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World.prototype.isInert = function () {
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return this.eventQueue.length === 0
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&& this.processActions.length === 0
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&& Route.is_emptySet(this.runnablePids);
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};
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World.prototype.markPidRunnable = function (pid) {
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this.runnablePids[pid] = [pid];
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};
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World.prototype.step = function () {
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this.dispatchEvents();
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this.performActions();
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this.stepChildren();
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return this.alive && !this.isInert();
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};
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World.prototype.asChild = function (pid, f, omitLivenessCheck) {
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if (!(pid in this.processTable) && !omitLivenessCheck) {
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console.warn("World.asChild eliding invocation of dead process", pid);
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return;
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}
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World.stack.push([this, pid]);
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var result = null;
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try {
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result = f();
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} catch (e) {
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this.kill(pid, e);
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}
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if (World.stack.pop()[0] !== this) {
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throw new Error("Internal error: World stack imbalance");
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}
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return result;
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};
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World.prototype.kill = function (pid, exn) {
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if (exn && exn.stack) {
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console.log("Process exited", pid, exn, exn.stack);
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} else {
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console.log("Process exited", pid, exn);
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}
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var p = this.processTable[pid];
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if (p && p.behavior.trapexit) {
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this.asChild(pid, function () { return p.behavior.trapexit(exn); });
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}
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delete this.processTable[pid];
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if (p) {
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if (exn) {
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p.exitReason = exn;
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this.tombstones[pid] = p;
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}
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this.applyAndIssueRoutingUpdate(p.gestalt, Route.emptyGestalt);
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}
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};
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World.prototype.stepChildren = function () {
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var pids = this.runnablePids;
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this.runnablePids = {};
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for (var pid in pids) {
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var p = this.processTable[pid];
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if (p && p.behavior.step /* exists, haven't called it yet */) {
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var childBusy = this.asChild(pid | 0, function () { return p.behavior.step() });
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if (childBusy) this.markPidRunnable(pid);
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}
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}
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};
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World.prototype.performActions = function () {
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var queue = this.processActions;
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this.processActions = [];
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var item;
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while ((item = queue.shift()) && this.alive) {
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this.performAction(item[0], item[1]);
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}
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};
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World.prototype.dispatchEvents = function () {
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var queue = this.eventQueue;
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this.eventQueue = [];
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var item;
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while ((item = queue.shift())) {
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this.dispatchEvent(item);
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}
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};
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World.prototype.performAction = function (pid, action) {
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switch (action.type) {
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case "spawn":
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var pid = World.nextPid++;
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var newGestalt = action.initialGestalt.label(pid);
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this.processTable[pid] = { gestalt: newGestalt, behavior: action.behavior };
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if (action.behavior.boot) {
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this.asChild(pid, function () { action.behavior.boot() });
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this.markPidRunnable(pid);
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}
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this.applyAndIssueRoutingUpdate(Route.emptyGestalt, newGestalt, pid);
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break;
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case "routes":
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if (pid in this.processTable) {
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// it may not be: this might be the routing update from a
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// kill of the process
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var oldGestalt = this.processTable[pid].gestalt;
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var newGestalt = action.gestalt.label(pid|0);
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// ^ pid|0: convert pid from string (table key!) to integer
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this.processTable[pid].gestalt = newGestalt;
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this.applyAndIssueRoutingUpdate(oldGestalt, newGestalt, pid);
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}
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break;
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case "message":
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if (action.metaLevel === 0) {
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this.eventQueue.push(action);
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} else {
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World.send(action.message, action.metaLevel - 1, action.isFeedback);
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}
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break;
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case "shutdownWorld":
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this.alive = false; // force us to stop doing things immediately
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World.exit();
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break;
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default:
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var exn = new Error("Action type " + action.type + " not understood");
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exn.action = action;
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throw exn;
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}
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};
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World.prototype.updateFullGestalt = function () {
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this.fullGestalt = this.partialGestalt.union(this.downwardGestalt);
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};
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World.prototype.issueLocalRoutingUpdate = function (affectedSubgestalt, knownTarget) {
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this.eventQueue.push(pendingRoutingUpdate(this.fullGestalt,
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affectedSubgestalt,
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knownTarget));
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};
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World.prototype.applyAndIssueRoutingUpdate = function (oldg, newg, knownTarget) {
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knownTarget = typeof knownTarget === 'undefined' ? null : knownTarget;
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this.partialGestalt = this.partialGestalt.erasePath(oldg).union(newg);
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this.updateFullGestalt();
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this.issueLocalRoutingUpdate(oldg.union(newg), knownTarget);
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World.updateRoutes([this.partialGestalt.drop()]);
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};
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World.prototype.dispatchEvent = function (e) {
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switch (e.type) {
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case "pendingRoutingUpdate":
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var pids = e.affectedSubgestalt.match(e.aggregate);
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if (e.knownTarget !== null) pids.unshift(e.knownTarget);
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for (var i = 0; i < pids.length; i++) {
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var pid = pids[i];
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if (pid === "out") console.warn("Would have delivered a routing update to environment");
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var p = this.processTable[pid];
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if (p) {
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var g = e.aggregate.filter(p.gestalt);
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this.asChild(pid, function () { p.behavior.handleEvent(updateRoutes([g])) });
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this.markPidRunnable(pid);
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}
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}
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break;
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case "message":
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var pids = this.partialGestalt.matchValue(e.message, e.metaLevel, e.isFeedback);
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for (var i = 0; i < pids.length; i++) {
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var pid = pids[i];
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var p = this.processTable[pid];
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this.asChild(pid, function () { p.behavior.handleEvent(e) });
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this.markPidRunnable(pid);
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}
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break;
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default:
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var exn = new Error("Event type " + e.type + " not dispatchable");
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exn.event = e;
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throw exn;
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}
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};
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World.prototype.handleEvent = function (e) {
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switch (e.type) {
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case "routes":
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var oldDownward = this.downwardGestalt;
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this.downwardGestalt = e.gestalt.label("out").lift();
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this.updateFullGestalt();
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this.issueLocalRoutingUpdate(oldDownward.union(this.downwardGestalt), null);
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break;
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case "message":
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this.eventQueue.push(sendMessage(e.message, e.metaLevel + 1, e.isFeedback));
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break;
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default:
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var exn = new Error("Event type " + e.type + " not understood");
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exn.event = e;
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throw exn;
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}
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};
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/* Debugging, management, and monitoring */
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World.prototype.processTree = function () {
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var kids = [];
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for (var pid in this.processTable) {
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var p = this.processTable[pid];
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if (p.behavior instanceof World) {
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kids.push([pid, p.behavior.processTree()]);
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} else {
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kids.push([pid, p]);
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}
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}
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for (var pid in this.tombstones) {
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kids.push([pid, this.tombstones[pid]]);
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}
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kids.sort();
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return kids;
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};
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World.prototype.textProcessTree = function (ownPid) {
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var lines = [];
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function dumpProcess(prefix, pid, p) {
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if (p instanceof Array) {
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lines.push(prefix + '--+ ' + pid);
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for (var i = 0; i < p.length; i++) {
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dumpProcess(prefix + ' |', p[i][0], p[i][1]);
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}
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lines.push(prefix);
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} else {
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var label = p.behavior.name || p.behavior.constructor.name || '';
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var tombstoneString = p.exitReason ? ' (EXITED: ' + p.exitReason + ') ' : '';
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lines.push(prefix + '-- ' + pid + ': ' + label +
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tombstoneString +
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JSON.stringify(p.behavior, function (k, v) {
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return k === 'name' ? undefined : v;
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}));
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}
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}
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dumpProcess('', ownPid || '', this.processTree());
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return lines.join('\n');
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};
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World.prototype.clearTombstones = function () {
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this.tombstones = {};
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for (var pid in this.processTable) {
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var p = this.processTable[pid];
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if (p.behavior instanceof World) {
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p.behavior.clearTombstones();
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}
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}
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};
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/*---------------------------------------------------------------------------*/
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/* Utilities: matching demand for some service */
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function DemandMatcher(projection, metaLevel, options) {
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options = $.extend({
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demandLevel: 0,
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supplyLevel: 0,
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demandSideIsSubscription: false
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}, options);
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this.pattern = Route.projectionToPattern(projection);
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this.projectionSpec = Route.compileProjection(projection);
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this.metaLevel = metaLevel | 0;
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this.demandLevel = options.demandLevel;
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this.supplyLevel = options.supplyLevel;
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this.demandSideIsSubscription = options.demandSideIsSubscription;
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this.onDemandIncrease = function (captures) {
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console.error("Unhandled increase in demand for route", captures);
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};
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this.onSupplyDecrease = function (captures) {
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console.error("Unhandled decrease in supply for route", captures);
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};
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this.currentDemand = {};
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this.currentSupply = {};
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}
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DemandMatcher.prototype.boot = function () {
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var observerLevel = 1 + Math.max(this.demandLevel, this.supplyLevel);
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World.updateRoutes([sub(this.pattern, this.metaLevel, observerLevel),
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pub(this.pattern, this.metaLevel, observerLevel)]);
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};
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DemandMatcher.prototype.handleEvent = function (e) {
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if (e.type === "routes") {
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this.handleGestalt(e.gestalt);
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}
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};
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DemandMatcher.prototype.handleGestalt = function (gestalt) {
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var newDemandMatcher = gestalt.project(this.projectionSpec,
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!this.demandSideIsSubscription,
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this.metaLevel,
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this.demandLevel);
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var newSupplyMatcher = gestalt.project(this.projectionSpec,
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this.demandSideIsSubscription,
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this.metaLevel,
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this.supplyLevel);
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var newDemand = Route.arrayToSet(Route.matcherKeys(newDemandMatcher));
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var newSupply = Route.arrayToSet(Route.matcherKeys(newSupplyMatcher));
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var demandDelta = Route.setSubtract(newDemand, this.currentDemand);
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var supplyDelta = Route.setSubtract(this.currentSupply, newSupply);
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var demandIncr = Route.setSubtract(demandDelta, newSupply);
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var supplyDecr = Route.setIntersect(supplyDelta, newDemand);
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this.currentDemand = newDemand;
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this.currentSupply = newSupply;
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for (var k in demandIncr) this.onDemandIncrease(demandIncr[k]);
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for (var k in supplyDecr) this.onSupplyDecrease(supplyDecr[k]);
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};
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/*---------------------------------------------------------------------------*/
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/* Utilities: deduplicator */
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function Deduplicator(ttl_ms) {
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this.ttl_ms = ttl_ms || 10000;
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this.queue = [];
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this.map = {};
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this.timerId = null;
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}
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Deduplicator.prototype.accept = function (m) {
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var s = JSON.stringify(m);
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if (s in this.map) return false;
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var entry = [(+new Date()) + this.ttl_ms, s, m];
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this.map[s] = entry;
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this.queue.push(entry);
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if (this.timerId === null) {
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var self = this;
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this.timerId = setInterval(function () { self.expireMessages(); },
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this.ttl_ms > 1000 ? 1000 : this.ttl_ms);
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}
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return true;
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};
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Deduplicator.prototype.expireMessages = function () {
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var now = +new Date();
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while (this.queue.length > 0 && this.queue[0][0] <= now) {
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var entry = this.queue.shift();
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delete this.map[entry[1]];
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}
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if (this.queue.length === 0) {
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clearInterval(this.timerId);
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this.timerId = null;
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}
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};
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/*---------------------------------------------------------------------------*/
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/* Ground interface */
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function Ground(bootFn) {
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var self = this;
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this.stepperId = null;
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World.withWorldStack([[this, -1]], function () {
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self.world = new World(bootFn);
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});
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}
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Ground.prototype.step = function () {
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var self = this;
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return World.withWorldStack([[this, -1]], function () {
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return self.world.step();
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});
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};
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Ground.prototype.checkPid = function (pid) {
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if (pid !== -1) console.error("Weird pid in Ground markPidRunnable", pid);
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};
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Ground.prototype.markPidRunnable = function (pid) {
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this.checkPid(pid);
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this.startStepping();
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};
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Ground.prototype.startStepping = function () {
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var self = this;
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if (this.stepperId) return;
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if (this.step()) {
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this.stepperId = setTimeout(function () {
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self.stepperId = null;
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self.startStepping();
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}, 0);
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}
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};
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Ground.prototype.stopStepping = function () {
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if (this.stepperId) {
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clearTimeout(this.stepperId);
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this.stepperId = null;
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}
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};
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Ground.prototype.enqueueAction = function (pid, action) {
|
|
this.checkPid(pid);
|
|
if (action.type === 'routes') {
|
|
if (!action.gestalt.isEmpty()) {
|
|
console.error("You have subscribed to a nonexistent event source.",
|
|
action.gestalt.pretty());
|
|
}
|
|
} else {
|
|
console.error("You have sent a message into the outer void.", action);
|
|
}
|
|
};
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
|
|
module.exports.__ = __;
|
|
module.exports._$ = _$;
|
|
|
|
module.exports.sub = sub;
|
|
module.exports.pub = pub;
|
|
module.exports.spawn = spawn;
|
|
module.exports.updateRoutes = updateRoutes;
|
|
module.exports.sendMessage = sendMessage;
|
|
module.exports.shutdownWorld = shutdownWorld;
|
|
|
|
module.exports.World = World;
|
|
module.exports.DemandMatcher = DemandMatcher;
|
|
module.exports.Deduplicator = Deduplicator;
|
|
module.exports.Ground = Ground;
|
|
module.exports.Route = Route;
|