implement attribution class that is de-duplicated in IdMap

src/index.js

@@ -103,7 +103,9 @@ export {
   equalIdSets,
   createDeleteSetFromStructStore,
   IdMap,
-  createIdMap
+  createIdMap,
+  createAttribution,
+  Attribution
 } from './internals.js'
 
 const glo = /** @type {any} */ (typeof globalThis !== 'undefined'

src/utils/IdMap.js

@@ -5,6 +5,50 @@ import {
 } from '../internals.js'
 
 import * as array from 'lib0/array'
+import * as map from 'lib0/map'
+import * as encoding from 'lib0/encoding'
+import * as buf from 'lib0/buffer'
+import * as rabin from 'lib0/hash/rabin'
+
+/**
+ * @template V
+ */
+export class Attribution {
+  /**
+   * @param {string} name
+   * @param {V} val
+   */
+  constructor (name, val) {
+    this.name = name
+    this.val = val
+  }
+
+  hash () {
+    const encoder = encoding.createEncoder()
+    encoding.writeVarString(encoder, this.name)
+    encoding.writeAny(encoder, /** @type {any} */ (this.val))
+    return buf.toBase64(rabin.fingerprint(rabin.StandardIrreducible128, encoding.toUint8Array(encoder)))
+  }
+}
+
+/**
+ * @param {Attribution<any>} attr
+ */
+const _hashAttribution = attr => {
+  const encoder = encoding.createEncoder()
+  encoding.writeVarString(encoder, attr.name)
+  encoding.writeAny(encoder, attr.val)
+  return buf.toBase64(rabin.fingerprint(rabin.StandardIrreducible128, encoding.toUint8Array(encoder)))
+}
+
+
+/**
+ * @template V
+ * @param {string} name
+ * @param {V} val
+ * @return {Attribution<V>}
+ */
+export const createAttribution = (name, val) => new Attribution(name, val)
 
 /**
  * @template T
@@ -35,7 +79,7 @@ export class AttrRange {
   /**
    * @param {number} clock
    * @param {number} len
-   * @param {Array<Attrs>} attrs
+   * @param {Array<Attribution<Attrs>>} attrs
    */
   constructor (clock, len, attrs) {
     /**
@@ -79,7 +123,7 @@ export class AttrRanges {
   /**
    * @param {number} clock
    * @param {number} length
-   * @param {Array<Attrs>} attrs
+   * @param {Array<Attribution<Attrs>>} attrs
    */
   add (clock, length, attrs) {
     this.sorted = false
@@ -168,11 +212,20 @@ export class AttrRanges {
 }
 
 /**
+ * Merge multiple idmaps. Ensures that there are no redundant attribution definitions (two
+ * Attributions that describe the same thing).
+ *
  * @template T
  * @param {Array<IdMap<T>>} ams
  * @return {IdMap<T>} A fresh IdSet
  */
 export const mergeIdMaps = ams => {
+  /**
+   * Maps attribution to the attribution of the merged idmap.
+   *
+   * @type {Map<Attribution<any>,Attribution<any>>}
+   */
+  const attrMapper = new Map()
   const merged = createIdMap()
   for (let amsI = 0; amsI < ams.length; amsI++) {
     ams[amsI].clients.forEach((rangesLeft, client) => {
@@ -186,6 +239,14 @@ export const mergeIdMaps = ams => {
             array.appendTo(ids, nextIds.getIds())
           }
         }
+        ids.forEach(id => {
+          // @ts-ignore
+          id.attrs = id.attrs.map(attr =>
+            map.setIfUndefined(attrMapper, attr, () =>
+              _ensureAttrs(merged, [attr])[0]
+            )
+          )
+        })
         merged.clients.set(client, new AttrRanges(ids))
       }
     })
@@ -202,6 +263,14 @@ export class IdMap {
      * @type {Map<number,AttrRanges<Attrs>>}
      */
     this.clients = new Map()
+    /**
+     * @type {Map<string, Attribution<Attrs>>}
+     */
+    this.attrsH = new Map()
+    /**
+     * @type {Set<Attribution<Attrs>>}
+     */
+    this.attrs = new Set()
   }
 
   /**
@@ -253,9 +322,10 @@ export class IdMap {
    * @param {number} client
    * @param {number} clock
    * @param {number} len
-   * @param {Array<Attrs>} attrs
+   * @param {Array<Attribution<Attrs>>} attrs
    */
   add (client, clock, len, attrs) {
+    attrs = _ensureAttrs(this, attrs)
     const ranges = this.clients.get(client)
     if (ranges == null) {
       this.clients.set(client, new AttrRanges([new AttrRange(clock, len, attrs)]))
@@ -265,15 +335,27 @@ export class IdMap {
   }
 }
 
+/**
+ * @template Attrs
+ * @param {IdMap<Attrs>} idmap
+ * @param {Array<Attribution<Attrs>>} attrs
+ * @return {Array<Attribution<Attrs>>}
+ */
+const _ensureAttrs = (idmap, attrs) => attrs.map(attr =>
+  idmap.attrs.has(attr) ? attr : map.setIfUndefined(idmap.attrsH, _hashAttribution(attr), () => {
+    idmap.attrs.add(attr)
+    return attr
+  }))
+
 export const createIdMap = () => new IdMap()
 
 /**
  * Remove all ranges from `exclude` from `ds`. The result is a fresh IdMap containing all ranges from `idSet` that are not
  * in `exclude`.
  *
- * @template {IdMap<any>} Set
+ * @template {IdMap<any>} ISet
- * @param {Set} set
+ * @param {ISet} set
  * @param {IdSet | IdMap<any>} exclude
- * @return {Set}
+ * @return {ISet}
  */
 export const diffIdMap = _diffSet

src/utils/StructStore.js

@@ -24,6 +24,7 @@ export class StructStore {
      */
     this.pendingDs = null
   }
+
   get ds () {
     return createDeleteSetFromStructStore(this)
   }

src/utils/Transaction.js

@@ -11,7 +11,7 @@ import {
   createID,
   cleanupYTextAfterTransaction,
   IdSet, UpdateEncoderV1, UpdateEncoderV2, GC, StructStore, AbstractType, AbstractStruct, YEvent, Doc, // eslint-disable-line
-  insertIntoIdSet
+  // insertIntoIdSet
 } from '../internals.js'
 
 import * as error from 'lib0/error'

tests/IdMap.tests.js

@@ -1,6 +1,6 @@
 import * as t from 'lib0/testing'
 import * as am from '../src/utils/IdMap.js'
-import { compareIdmaps, createIdMap, ID, createRandomIdSet, createRandomIdMap } from './testHelper.js'
+import { compareIdmaps, createIdMap, ID, createRandomIdSet, createRandomIdMap, createAttribution } from './testHelper.js'
 
 /**
  * @template T
@@ -9,7 +9,7 @@ import { compareIdmaps, createIdMap, ID, createRandomIdSet, createRandomIdMap }
 const simpleConstructAttrs = ops => {
   const attrs = createIdMap()
   ops.forEach(op => {
-    attrs.add(op[0], op[1], op[2], op[3])
+    attrs.add(op[0], op[1], op[2], op[3].map(v => createAttribution('', v)))
   })
   return attrs
 }

tests/testHelper.js

@@ -8,7 +8,7 @@ import * as map from 'lib0/map'
 import * as Y from '../src/index.js'
 import * as math from 'lib0/math'
 import {
-  idmapAttrsEqual, createIdSet, createIdMap, addToIdSet
+  createIdSet, createIdMap, addToIdSet
 } from '../src/internals.js'
 
 export * from '../src/index.js'
@@ -327,6 +327,28 @@ export const compareIdSets = (idSet1, idSet2) => {
   return true
 }
 
+/**
+ * only use for testing
+ *
+ * @template T
+ * @param {Array<Y.Attribution<T>>} attrs
+ * @param {Y.Attribution<T>} attr
+ *
+ */
+const _idmapAttrsHas = (attrs, attr) => {
+  const hash = attr.hash()
+  return attrs.find(a => a.hash() === hash)
+}
+
+/**
+ * only use for testing
+ *
+ * @template T
+ * @param {Array<Y.Attribution<T>>} a
+ * @param {Array<Y.Attribution<T>>} b
+ */
+export const _idmapAttrsEqual = (a, b) => a.length === b.length && a.every(v => _idmapAttrsHas(b, v))
+
 /**
  * @template T
  * @param {Y.IdMap<T>} am1
@@ -341,7 +363,7 @@ export const compareIdmaps = (am1, am2) => {
     for (let i = 0; i < items1.length; i++) {
       const di1 = items1[i]
       const di2 = /** @type {Array<import('../src/utils/IdMap.js').AttrRange<T>>} */ (items2)[i]
-      t.assert(di1.clock === di2.clock && di1.len === di2.len && idmapAttrsEqual(di1.attrs, di2.attrs))
+      t.assert(di1.clock === di2.clock && di1.len === di2.len && _idmapAttrsEqual(di1.attrs, di2.attrs))
     }
   }
   return true
@@ -392,7 +414,7 @@ export const createRandomIdMap = (gen, clients, clockRange, attrChoices) => {
         attrs.push(a)
       }
     }
-    idMap.add(client, clockStart, len, attrs)
+    idMap.add(client, clockStart, len, attrs.map(v => Y.createAttribution('', v)))
   }
   return idMap
 }