#28: Removing transaction hashing from core

src/engine/ControlMessage.ts

@@ -1,4 +1,3 @@
-import { Hash } from './hash';
 import { TreeClock } from './clocks';
 import { MeldError, MeldErrorStatus } from './MeldError';
 const inspect = Symbol.for('nodejs.util.inspect.custom');
@@ -76,19 +75,17 @@ export namespace Response {
     constructor(
       readonly lastTime: TreeClock,
       readonly quadsAddress: string,
-      readonly lastHash: Hash,
       readonly updatesAddress: string) {
     }
 
     readonly toJson = () => ({
       '@type': 'http://control.m-ld.org/response/snapshot',
       lastTime: this.lastTime.toJson(),
       quadsAddress: this.quadsAddress,
-      lastHash: this.lastHash.encode(),
       updatesAddress: this.updatesAddress
     });
 
-    toString = () => `Snapshot at ${this.lastTime} with ${this.lastHash}`;
+    toString = () => `Snapshot at ${this.lastTime}`;
     [inspect] = () => this.toString();
   }
 
@@ -145,7 +142,6 @@ export namespace Response {
           if (lastTime)
             return new Snapshot(
               lastTime, json.quadsAddress,
-              Hash.decode(json.lastHash),
               json.updatesAddress);
           break;
         case 'http://control.m-ld.org/response/revup':

src/engine/MeldEncoding.ts

@@ -1,13 +1,11 @@
 import { MeldDelta, EncodedDelta, UUID } from '.';
 import { NamedNode, Quad } from 'rdf-js';
 import { literal, namedNode, blankNode, triple as newTriple, defaultGraph, quad as newQuad } from '@rdfjs/data-model';
-import { HashBagBlock } from './blocks';
-import { Hash } from './hash';
 import { compact } from 'jsonld';
 import { flatten } from './util';
 import { Context, ExpandedTermDef } from '../jrql-support';
 import { Iri } from 'jsonld/jsonld-spec';
-import { Triple, tripleKey, TripleMap } from './quads';
+import { Triple, TripleMap } from './quads';
 import { rdfToJson, jsonToRdf } from "./jsonld";
 
 export class DomainContext implements Context {
@@ -39,10 +37,6 @@ namespace rdf {
   export const object = namedNode($id + 'object');
 }
 
-export function hashTriple(triple: Triple): Hash {
-  return Hash.digest(...tripleKey(triple));
-}
-
 export function reifyTriplesTids(triplesTids: TripleMap<UUID[]>): Triple[] {
   return flatten([...triplesTids].map(([triple, tids]) => {
     const rid = blankNode();
@@ -80,17 +74,6 @@ export function unreify(reifications: Triple[]): [Triple, UUID[]][] {
   }, {} as { [rid: string]: [Triple, UUID[]] }));
 }
 
-export class JsonDeltaBagBlock extends HashBagBlock<EncodedDelta> {
-  constructor(id: Hash, data?: EncodedDelta) { super(id, data); }
-  protected construct = (id: Hash, data: EncodedDelta) => new JsonDeltaBagBlock(id, data);
-  protected hash = (data: EncodedDelta) => {
-    const [ver, tid, del, ins] = data;
-    if (ver !== 0)
-      throw new Error(`Encoded delta version ${ver} not supported`);
-    return Hash.digest(tid, ins, del); // Note delete insert reversed (historical)
-  };
-}
-
 /**
  * TODO: re-sync with Java
  * @see m-ld/m-ld-core/src/main/java/org/m_ld/MeldResource.java

src/engine/PubsubRemotes.ts

@@ -1,4 +1,4 @@
-import { Snapshot, DeltaMessage, MeldRemotes, MeldLocal, UUID, Revup } from '.';
+import { Snapshot, DeltaMessage, MeldRemotes, MeldLocal, Revup } from '.';
 import { Observable, Subject as Source, BehaviorSubject, identity } from 'rxjs';
 import { TreeClock } from './clocks';
 import { generate as uuid } from 'short-uuid';
@@ -157,7 +157,7 @@ export abstract class PubsubRemotes extends AbstractMeld implements MeldRemotes
     // Ack the response to start the streams
     ack.resolve();
     sw.stop();
-    return { lastTime: res.lastTime, lastHash: res.lastHash, quads, updates };
+    return { lastTime: res.lastTime, quads, updates };
   }
 
   private triplesFromBuffer = (payload: Buffer) =>
@@ -365,10 +365,10 @@ export abstract class PubsubRemotes extends AbstractMeld implements MeldRemotes
   }
 
   private async replySnapshot(sentParams: DirectParams, snapshot: Snapshot): Promise<void> {
-    const { lastTime, lastHash, quads, updates } = snapshot;
+    const { lastTime, quads, updates } = snapshot;
     const quadsAddress = uuid(), updatesAddress = uuid();
     await this.reply(sentParams, new Response.Snapshot(
-      lastTime, quadsAddress, lastHash, updatesAddress
+      lastTime, quadsAddress, updatesAddress
     ), 'expectAck');
     // Ack has been sent, start streaming the data and updates concurrently
     await Promise.all([

src/engine/dataset/DatasetEngine.ts

@@ -130,9 +130,9 @@ export class DatasetEngine extends AbstractMeld implements CloneEngine, MeldLoca
     if (this.newClone)
       // For a new non-genesis clone, the first connect is essential.
       await comesAlive(this);
-    else
-      // For any other clone, just wait for decided liveness.
-      await comesAlive(this, 'notNull');
+    // else
+    //   // For any other clone, just wait for decided liveness.
+    //   await comesAlive(this, 'notNull');
   }
 
   private reconnectDelayer = (style: ConnectStyle): Observable<number> => {

src/engine/dataset/SuSetDataset.ts

@@ -2,21 +2,20 @@ import { MeldUpdate, MeldConstraint, MeldReadState, readResult, Resource, ReadRe
 import { Snapshot, UUID, DeltaMessage, MeldDelta } from '..';
 import { Quad } from 'rdf-js';
 import { TreeClock } from '../clocks';
-import { Hash } from '../hash';
 import { Subject } from '../../jrql-support';
 import { Dataset, PatchQuads } from '.';
 import { flatten as flatJsonLd } from 'jsonld';
 import { Iri } from 'jsonld/jsonld-spec';
 import { JrqlGraph } from './JrqlGraph';
-import { MeldEncoding, unreify, hashTriple, toDomainQuad, reifyTriplesTids } from '../MeldEncoding';
+import { MeldEncoding, unreify, toDomainQuad, reifyTriplesTids } from '../MeldEncoding';
 import { Observable, from, Subject as Source, EMPTY } from 'rxjs';
 import { bufferCount, mergeMap, reduce, map, filter, takeWhile, expand } from 'rxjs/operators';
 import { flatten, Future, tapComplete, getIdLogger, check } from '../util';
 import { generate as uuid } from 'short-uuid';
 import { Logger } from 'loglevel';
 import { MeldError } from '../MeldError';
 import { LocalLock } from '../local';
-import { SUSET_CONTEXT, qsName, toPrefixedId } from './SuSetGraph';
+import { SUSET_CONTEXT, qsName, tripleId } from './SuSetGraph';
 import { SuSetJournalGraph, SuSetJournalEntry } from './SuSetJournal';
 import { MeldConfig, Read } from '../..';
 import { QuadMap, TripleMap, Triple } from '../quads';
@@ -135,15 +134,6 @@ export class SuSetDataset extends JrqlGraph {
     });
   }
 
-  /**
-   * @return the last hash seen in the journal.
-   */
-  @SuSetDataset.checkNotClosed.async
-  async lastHash(): Promise<Hash> {
-    const journal = await this.journalGraph.journal();
-    return (await journal.tail()).hash;
-  }
-
   /**
    * Emits entries from the journal since a time given as a clock or a tick.
    * The clock variant accepts a remote or local clock and provides operations
@@ -432,7 +422,7 @@ export class SuSetDataset extends JrqlGraph {
     const dataReset = this.dataset.transact({
       id: 'suset-reset',
       prepare: async () =>
-        ({ patch: await this.journalGraph.reset(snapshot.lastHash, snapshot.lastTime, localTime) })
+        ({ patch: await this.journalGraph.reset(snapshot.lastTime, localTime) })
     });
 
     const quadsApplied = snapshot.quads.pipe(
@@ -469,7 +459,6 @@ export class SuSetDataset extends JrqlGraph {
           const tail = await journal.tail();
           resolve({
             lastTime: tail.gwc,
-            lastHash: tail.hash,
             quads: this.graph.match().pipe(
               bufferCount(10), // TODO batch size config
               mergeMap(async batch => reifyTriplesTids(
@@ -483,7 +472,3 @@ export class SuSetDataset extends JrqlGraph {
     });
   }
 }
-
-function tripleId(triple: Triple): string {
-  return toPrefixedId('thash', hashTriple(triple).encode());
-}

src/engine/dataset/SuSetGraph.ts

@@ -1,6 +1,9 @@
 import { Context } from '../../jrql-support';
 import { namedNode } from '@rdfjs/data-model';
 import { NamedNode } from 'rdf-js';
+import { Iri } from 'jsonld/jsonld-spec';
+import { Triple, tripleKey } from '../quads';
+import { createHash } from 'crypto';
 
 /**
  * Context for SU-Set Dataset code to manipulate control content.
@@ -25,6 +28,16 @@ export function qsName(name: string): NamedNode {
   return namedNode(SUSET_CONTEXT.qs + name);
 }
 
-export function toPrefixedId(prefix: string, ...path: string[]) {
+export function toPrefixedId(prefix: string, ...path: string[]): Iri {
   return `${prefix}:${path.map(encodeURIComponent).join('/')}`;
-}
+}
+
+export function fromPrefixedId(prefix: string, id: Iri): string[] {
+  return id.match(`^${prefix}:(.+)`)?.[1]?.split('/').map(decodeURIComponent) ?? [];
+}
+
+export function tripleId(triple: Triple): string {
+  const hash = createHash('sha1'); // Fastest
+  tripleKey(triple).forEach(key => hash.update(key));
+  return toPrefixedId('thash', hash.digest('base64'));
+}