onioncollab/src/onion/version_parser.ts

import {Buffer} from "buffer"; // NodeJS library

import {Delta} from "./delta";
import {VersionRegistry} from "./version";
import {DeltaParser} from "./delta_parser";

export class VersionParser {
  readonly deltaParser: DeltaParser;
  readonly versionRegistry: VersionRegistry;

  constructor(deltaParser: DeltaParser, versionRegistry: VersionRegistry) {
    this.deltaParser = deltaParser;
    this.versionRegistry = versionRegistry;
  }

  load({externalDependencies, deltas, versions}, onLoadDelta: (Delta) => void, onLoadVersion: (Version) => void) {
    for (const e of externalDependencies) {
      if (this.versionRegistry.lookupOptional(Buffer.from(e, 'hex')) === undefined) {
        throw new Error("Cannot load versions: missing dependency: " + e);
      }
    }
    for (const d of deltas) {
      const loadedDelta = this.deltaParser.loadDelta(d);
      onLoadDelta(loadedDelta);
    }

    for (const {id, delta, parent, embeddings} of versions) {
      const parentVersion = this.versionRegistry.lookup(Buffer.from(parent, 'hex'));
      const parentDelta = this.deltaParser.deltaRegistry.deltas.get(delta)!;
      const theEmbeddings = new Map();
      const selfEmbeddingKeys = new Set<string>();
      for (const {guestId, v, ovr} of embeddings) {
        console.log({guestId, v, id})
        if (v === id) {
          selfEmbeddingKeys.add(guestId);
        }
        else {
          const guestVersion = this.versionRegistry.lookupOptional(Buffer.from(v, 'hex'));
          for (const [key,val] of Object.entries(ovr)) {
            const guestDelta = this.deltaParser.deltaRegistry.deltas.get(key as string);
            const hostDelta = this.deltaParser.deltaRegistry.deltas.get(val as string);
            theEmbeddings.set(guestDelta, hostDelta);
          }
        }
      }
      const loadedVersion = this.versionRegistry.createVersion(parentVersion, parentDelta, newVersion => {
        for (const guestId of selfEmbeddingKeys) {
          theEmbeddings.set(guestId, {version: newVersion, overridings: new Map()});
        }
        return theEmbeddings;
      });
      onLoadVersion(loadedVersion);
    }
  }
}