@langchain/langgraph
Version:
LangGraph
207 lines • 7.01 kB
JavaScript
import { EmptyChannelError, InvalidUpdateError } from "../errors.js";
import { BaseChannel } from "./base.js";
import { areSetsEqual } from "./named_barrier_value.js";
function isWaitForNames(v) {
return v.__names !== undefined;
}
/**
* A channel that switches between two states
*
* - in the "priming" state it can't be read from.
* - if it receives a WaitForNames update, it switches to the "waiting" state.
* - in the "waiting" state it collects named values until all are received.
* - once all named values are received, it can be read once, and it switches
* back to the "priming" state.
* @internal
*/
export class DynamicBarrierValue extends BaseChannel {
constructor() {
super();
Object.defineProperty(this, "lc_graph_name", {
enumerable: true,
configurable: true,
writable: true,
value: "DynamicBarrierValue"
});
Object.defineProperty(this, "names", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
}); // Names of nodes that we want to wait for.
Object.defineProperty(this, "seen", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
this.names = undefined;
this.seen = new Set();
}
fromCheckpoint(checkpoint) {
const empty = new DynamicBarrierValue();
if (typeof checkpoint !== "undefined") {
empty.names = new Set(checkpoint[0]);
empty.seen = new Set(checkpoint[1]);
}
return empty;
}
update(values) {
const waitForNames = values.filter(isWaitForNames);
if (waitForNames.length > 0) {
if (waitForNames.length > 1) {
throw new InvalidUpdateError("Received multiple WaitForNames updates in the same step.");
}
this.names = new Set(waitForNames[0].__names);
return true;
}
else if (this.names !== undefined) {
let updated = false;
for (const value of values) {
if (isWaitForNames(value)) {
throw new Error("Assertion Error: Received unexpected WaitForNames instance.");
}
if (this.names.has(value) && !this.seen.has(value)) {
this.seen.add(value);
updated = true;
}
}
return updated;
}
return false;
}
consume() {
if (this.seen && this.names && areSetsEqual(this.seen, this.names)) {
this.seen = new Set();
this.names = undefined;
return true;
}
return false;
}
// If we have not yet seen all the node names we want to wait for,
// throw an error to prevent continuing.
get() {
if (!this.names || !areSetsEqual(this.names, this.seen)) {
throw new EmptyChannelError();
}
return undefined;
}
checkpoint() {
return [this.names ? [...this.names] : undefined, [...this.seen]];
}
isAvailable() {
return !!this.names && areSetsEqual(this.names, this.seen);
}
}
/**
* A channel that switches between two states with an additional finished flag
*
* - in the "priming" state it can't be read from.
* - if it receives a WaitForNames update, it switches to the "waiting" state.
* - in the "waiting" state it collects named values until all are received.
* - once all named values are received, and the finished flag is set, it can be read once, and it switches
* back to the "priming" state.
* @internal
*/
export class DynamicBarrierValueAfterFinish extends BaseChannel {
constructor() {
super();
Object.defineProperty(this, "lc_graph_name", {
enumerable: true,
configurable: true,
writable: true,
value: "DynamicBarrierValueAfterFinish"
});
Object.defineProperty(this, "names", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
}); // Names of nodes that we want to wait for.
Object.defineProperty(this, "seen", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "finished", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
this.names = undefined;
this.seen = new Set();
this.finished = false;
}
fromCheckpoint(checkpoint) {
const empty = new DynamicBarrierValueAfterFinish();
if (typeof checkpoint !== "undefined") {
const [names, seen, finished] = checkpoint;
empty.names = names ? new Set(names) : undefined;
empty.seen = new Set(seen);
empty.finished = finished;
}
return empty;
}
update(values) {
const waitForNames = values.filter(isWaitForNames);
if (waitForNames.length > 0) {
if (waitForNames.length > 1) {
throw new InvalidUpdateError("Received multiple WaitForNames updates in the same step.");
}
this.names = new Set(waitForNames[0].__names);
return true;
}
else if (this.names !== undefined) {
let updated = false;
for (const value of values) {
if (isWaitForNames(value)) {
throw new Error("Assertion Error: Received unexpected WaitForNames instance.");
}
if (this.names.has(value) && !this.seen.has(value)) {
this.seen.add(value);
updated = true;
}
}
return updated;
}
return false;
}
consume() {
if (this.finished &&
this.seen &&
this.names &&
areSetsEqual(this.seen, this.names)) {
this.seen = new Set();
this.names = undefined;
this.finished = false;
return true;
}
return false;
}
finish() {
if (!this.finished && this.names && areSetsEqual(this.names, this.seen)) {
this.finished = true;
return true;
}
return false;
}
get() {
if (!this.finished || !this.names || !areSetsEqual(this.names, this.seen)) {
throw new EmptyChannelError();
}
return undefined;
}
checkpoint() {
return [
this.names ? [...this.names] : undefined,
[...this.seen],
this.finished,
];
}
isAvailable() {
return this.finished && !!this.names && areSetsEqual(this.names, this.seen);
}
}
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