Merge pull request #17642 from overleaf/mj-optimize-range-fetch

[overleaf-editor-core] Load ranges and content in parallel

GitOrigin-RevId: aa949ae7532965c5476c58bacf4bf068620791c0

libraries/overleaf-editor-core/lib/file_data/hash_file_data.js

@@ -86,14 +86,16 @@ class HashFileData extends FileData {
    * @returns {Promise<LazyStringFileData>}
    */
   async toLazy(blobStore) {
-    const blob = await blobStore.getBlob(this.hash)
+    const [blob, rangesBlob] = await Promise.all([
-    let rangesBlob
+      blobStore.getBlob(this.hash),
-    if (this.rangesHash) {
+      this.rangesHash
-      rangesBlob = await blobStore.getBlob(this.rangesHash)
+        ? blobStore.getBlob(this.rangesHash)
-      if (!rangesBlob) {
+        : Promise.resolve(undefined),
+    ])
+    if (rangesBlob === null) {
+      // We attempted to look up the blob, but none was found
       throw new Error('Failed to look up rangesHash in blobStore')
     }
-    }
     if (!blob) throw new Error('blob not found: ' + this.hash)
     return FileData.createLazyFromBlobs(blob, rangesBlob)
   }

libraries/overleaf-editor-core/lib/file_data/lazy_string_file_data.js

@@ -110,16 +110,19 @@ class LazyStringFileData extends FileData {
    * @returns {Promise<EagerStringFileData>}
    */
   async toEager(blobStore) {
-    const content = await blobStore.getString(this.hash)
+    const [content, ranges] = await Promise.all([
-    let comments
+      blobStore.getString(this.hash),
-    let trackedChanges
+      this.rangesHash
-    if (this.rangesHash) {
+        ? /** @type {Promise<RangesBlob>} */ (
-      /** @type {RangesBlob} */
+            blobStore.getObject(this.rangesHash)
-      const ranges = await blobStore.getObject(this.rangesHash)
+          )
-      comments = ranges.comments
+        : Promise.resolve(undefined),
-      trackedChanges = ranges.trackedChanges
+    ])
-    }
+    const file = new EagerStringFileData(
-    const file = new EagerStringFileData(content, comments, trackedChanges)
+      content,
+      ranges?.comments,
+      ranges?.trackedChanges
+    )
     applyOperations(this.operations, file)
     return file
   }

libraries/overleaf-editor-core/test/hash_file_data.test.js

@@ -0,0 +1,125 @@
+const HashFileData = require('../lib/file_data/hash_file_data')
+const { expect } = require('chai')
+const StringFileData = require('../lib/file_data/string_file_data')
+const sinon = require('sinon')
+const Blob = require('../lib/blob')
+
+describe('HashFileData', function () {
+  beforeEach(function () {
+    this.fileHash = 'a5675307b61ec2517330622a6e649b4ca1ee5612'
+    this.rangesHash = '380de212d09bf8498065833dbf242aaf11184316'
+    this.blobStore = {
+      getString: sinon.stub(),
+      getObject: sinon.stub(),
+      getBlob: sinon.stub(),
+    }
+  })
+
+  describe('constructor', function () {
+    it('should create a new instance of HashFileData from content hash and ranges hash', function () {
+      const fileData = new HashFileData(this.fileHash, this.rangesHash)
+
+      expect(fileData).to.be.instanceOf(HashFileData)
+      expect(fileData.getHash()).to.equal(this.fileHash)
+      expect(fileData.getRangesHash()).to.equal(this.rangesHash)
+    })
+
+    it('should create a new instance of HashFileData with no ranges hash', function () {
+      const fileData = new HashFileData(this.fileHash)
+      expect(fileData).to.be.instanceOf(HashFileData)
+      expect(fileData.getHash()).to.equal(this.fileHash)
+      expect(fileData.getRangesHash()).to.be.undefined
+    })
+  })
+
+  describe('fromRaw', function () {
+    it('should create a new instance of HashFileData from raw data', function () {
+      const raw = { hash: this.fileHash, rangesHash: this.rangesHash }
+      const fileData = HashFileData.fromRaw(raw)
+
+      expect(fileData).to.be.instanceOf(HashFileData)
+      expect(fileData.getHash()).to.equal(raw.hash)
+      expect(fileData.getRangesHash()).to.equal(raw.rangesHash)
+    })
+
+    it('should create a new instance of HashFileData from raw data without ranges hash', function () {
+      const raw = { hash: this.fileHash }
+      const fileData = HashFileData.fromRaw(raw)
+
+      expect(fileData).to.be.instanceOf(HashFileData)
+      expect(fileData.getHash()).to.equal(raw.hash)
+      expect(fileData.getRangesHash()).to.equal(undefined)
+    })
+  })
+
+  describe('toRaw', function () {
+    it('should include ranges hash when present', function () {
+      const fileData = new HashFileData(this.fileHash, this.rangesHash)
+      const raw = fileData.toRaw()
+      expect(raw).to.deep.equal({
+        hash: this.fileHash,
+        rangesHash: this.rangesHash,
+      })
+    })
+
+    it('should omit ranges hash when not present', function () {
+      const fileData = new HashFileData(this.fileHash)
+      const raw = fileData.toRaw()
+      expect(raw).to.deep.equal({
+        hash: this.fileHash,
+      })
+    })
+  })
+
+  describe('toEager', function () {
+    it('should convert HashFileData to StringFileData including ranges', async function () {
+      const trackedChanges = [
+        {
+          range: { pos: 5, length: 10 },
+          tracking: {
+            userId: 'foo',
+            type: 'insert',
+            ts: '2024-01-01T00:00:00.000Z',
+          },
+        },
+      ]
+      const comments = [
+        {
+          id: 'comment-1',
+          ranges: [{ pos: 1, length: 4 }],
+          resolved: false,
+        },
+      ]
+      const fileData = new HashFileData(this.fileHash, this.rangesHash)
+      this.blobStore.getString.withArgs(this.fileHash).resolves('content')
+      this.blobStore.getObject.withArgs(this.rangesHash).resolves({
+        trackedChanges,
+        comments,
+      })
+      this.blobStore.getBlob
+        .withArgs(this.rangesHash)
+        .resolves(new Blob(this.rangesHash, 20, 20))
+      this.blobStore.getBlob
+        .withArgs(this.fileHash)
+        .resolves(new Blob(this.fileHash, 20, 20))
+      const eagerFileData = await fileData.toEager(this.blobStore)
+      expect(eagerFileData).to.be.instanceOf(StringFileData)
+      expect(eagerFileData.getContent()).to.equal('content')
+      expect(eagerFileData.trackedChanges.toRaw()).to.deep.equal(trackedChanges)
+      expect(eagerFileData.getComments()).to.deep.equal(comments)
+    })
+
+    it('should convert HashFileData to StringFileData without ranges', async function () {
+      const fileData = new HashFileData(this.fileHash, undefined)
+      this.blobStore.getString.withArgs(this.fileHash).resolves('content')
+      this.blobStore.getBlob
+        .withArgs(this.fileHash)
+        .resolves(new Blob(this.fileHash, 20, 20))
+      const eagerFileData = await fileData.toEager(this.blobStore)
+      expect(eagerFileData).to.be.instanceOf(StringFileData)
+      expect(eagerFileData.getContent()).to.equal('content')
+      expect(eagerFileData.trackedChanges.toRaw()).to.deep.equal([])
+      expect(eagerFileData.getComments()).to.deep.equal([])
+    })
+  })
+})