Changeset: Migrate from mergingOpAssembler() to squashOps()

Author: rhansen

CHANGELOG.md

@@ -24,6 +24,8 @@
   * `opIterator()`: Deprecated in favor of the new `deserializeOps()` generator
     function.
   * `opAssembler()`: Deprecated in favor of the new `serializeOps()` function.
+  * `mergingOpAssembler()`: Deprecated in favor of the new `squashOps()`
+    generator function (combined with `serializeOps()`).
   * `appendATextToAssembler()`: Deprecated in favor of the new `opsFromAText()`
     generator function.
   * `newOp()`: Deprecated in favor of the new `Op` class.

src/static/js/Changeset.js

@@ -338,7 +338,7 @@ class OpAssembler {
  * @yields {Op} The squashed operations.
  * @returns {Generator<Op>}
  */
-const squashOps = function* (ops, finalize) {
+exports.squashOps = function* (ops, finalize) {
   let prevOp = new Op();
   // If we get, for example, insertions [xxx\n,yyy], those don't merge, but if we get
   // [xxx\n,yyy,zzz\n], that merges to [xxx\nyyyzzz\n]. This variable stores the length of yyy and
@@ -402,7 +402,7 @@ class MergingOpAssembler {
   }
 
   _serialize(finalize) {
-    this._serialized = exports.serializeOps(squashOps(this._ops, finalize));
+    this._serialized = exports.serializeOps(exports.squashOps(this._ops, finalize));
   }
 
   append(op) {
@@ -465,32 +465,29 @@ const opsFromText = function* (opcode, text, attribs = '', pool = null) {
  */
 class SmartOpAssembler {
   constructor() {
-    this._minusAssem = new MergingOpAssembler();
-    this._plusAssem = new MergingOpAssembler();
-    this._keepAssem = new MergingOpAssembler();
     this._assem = exports.stringAssembler();
     this.clear();
   }
 
   clear() {
-    this._minusAssem.clear();
-    this._plusAssem.clear();
-    this._keepAssem.clear();
+    this._minusAssem = [];
+    this._plusAssem = [];
+    this._keepAssem = [];
     this._assem.clear();
     this._lastOpcode = '';
     this._lengthChange = 0;
   }
 
-  _flushKeeps() {
-    this._assem.append(this._keepAssem.toString());
-    this._keepAssem.clear();
+  _flushKeeps(finalize) {
+    this._assem.append(exports.serializeOps(exports.squashOps(this._keepAssem, finalize)));
+    this._keepAssem = [];
   }
 
   _flushPlusMinus() {
-    this._assem.append(this._minusAssem.toString());
-    this._minusAssem.clear();
-    this._assem.append(this._plusAssem.toString());
-    this._plusAssem.clear();
+    this._assem.append(exports.serializeOps(exports.squashOps(this._minusAssem, false)));
+    this._minusAssem = [];
+    this._assem.append(exports.serializeOps(exports.squashOps(this._plusAssem, false)));
+    this._plusAssem = [];
   }
 
   append(op) {
@@ -499,21 +496,21 @@ class SmartOpAssembler {
 
     if (op.opcode === '-') {
       if (this._lastOpcode === '=') {
-        this._flushKeeps();
+        this._flushKeeps(false);
       }
-      this._minusAssem.append(op);
+      this._minusAssem.push(copyOp(op));
       this._lengthChange -= op.chars;
     } else if (op.opcode === '+') {
       if (this._lastOpcode === '=') {
-        this._flushKeeps();
+        this._flushKeeps(false);
       }
-      this._plusAssem.append(op);
+      this._plusAssem.push(copyOp(op));
       this._lengthChange += op.chars;
     } else if (op.opcode === '=') {
       if (this._lastOpcode !== '=') {
         this._flushPlusMinus();
       }
-      this._keepAssem.append(op);
+      this._keepAssem.push(copyOp(op));
     }
     this._lastOpcode = op.opcode;
   }
@@ -537,12 +534,13 @@ class SmartOpAssembler {
 
   toString() {
     this._flushPlusMinus();
-    this._flushKeeps();
+    this._flushKeeps(false);
     return this._assem.toString();
   }
 
   endDocument() {
-    this._keepAssem.endDocument();
+    this._flushPlusMinus();
+    this._flushKeeps(true);
   }
 
   getLengthChange() {
@@ -608,9 +606,14 @@ exports.checkRep = (cs) => {
 exports.smartOpAssembler = () => new SmartOpAssembler();
 
 /**
+ * @deprecated Use `squashOps` with `serializeOps` instead.
  * @returns {MergingOpAssembler}
  */
-exports.mergingOpAssembler = () => new MergingOpAssembler();
+exports.mergingOpAssembler = () => {
+  padutils.warnWithStack(
+      'Changeset.mergingOpAssembler() is deprecated; use Changeset.squashOps() instead');
+  return new MergingOpAssembler();
+};
 
 /**
  * @deprecated Use `serializeOps` instead.
@@ -1322,12 +1325,12 @@ exports.mutateAttributionLines = (cs, lines, pool) => {
   let lineAssem = null;
 
   const outputMutOp = (op) => {
-    if (!lineAssem) lineAssem = new MergingOpAssembler();
-    lineAssem.append(op);
+    if (!lineAssem) lineAssem = [];
+    lineAssem.push(op);
     if (op.lines <= 0) return;
     assert(op.lines === 1, `Can't have op.lines of ${op.lines} in attribution lines`);
     // ship it to the mut
-    mut.insert(lineAssem.toString(), 1);
+    mut.insert(exports.serializeOps(exports.squashOps(lineAssem, false)), 1);
     lineAssem = null;
   };
 
@@ -1376,23 +1379,22 @@ exports.mutateAttributionLines = (cs, lines, pool) => {
  * @returns {string} joined Attribution lines
  */
 exports.joinAttributionLines = (theAlines) => {
-  const assem = new MergingOpAssembler();
-  for (const aline of theAlines) {
-    for (const op of exports.deserializeOps(aline)) assem.append(op);
-  }
-  return assem.toString();
+  const ops = (function* () {
+    for (const aline of theAlines) yield* exports.deserializeOps(aline);
+  })();
+  return exports.serializeOps(exports.squashOps(ops, false));
 };
 
 exports.splitAttributionLines = (attrOps, text) => {
-  const assem = new MergingOpAssembler();
+  let ops = [];
   const lines = [];
   let pos = 0;
 
   const appendOp = (op) => {
-    assem.append(op);
+    ops.push(op);
     if (op.lines > 0) {
-      lines.push(assem.toString());
-      assem.clear();
+      lines.push(exports.serializeOps(exports.squashOps(ops, false)));
+      ops = [];
     }
     pos += op.chars;
   };

src/static/js/changesettracker.js

@@ -143,21 +143,21 @@ const makeChangesetTracker = (scheduler, apool, aceCallbacksProvider) => {
         // Sanitize authorship: Replace all author attributes with this user's author ID in case the
         // text was copied from another author.
         const cs = Changeset.unpack(userChangeset);
-        const assem = Changeset.mergingOpAssembler();
-
-        for (const op of Changeset.deserializeOps(cs.ops)) {
-          if (op.opcode === '+') {
-            const attribs = AttributeMap.fromString(op.attribs, apool);
-            const oldAuthorId = attribs.get('author');
-            if (oldAuthorId != null && oldAuthorId !== authorId) {
-              attribs.set('author', authorId);
-              op.attribs = attribs.toString();
+        const ops = (function* () {
+          for (const op of Changeset.deserializeOps(cs.ops)) {
+            if (op.opcode === '+') {
+              const attribs = AttributeMap.fromString(op.attribs, apool);
+              const oldAuthorId = attribs.get('author');
+              if (oldAuthorId != null && oldAuthorId !== authorId) {
+                attribs.set('author', authorId);
+                op.attribs = attribs.toString();
+              }
             }
+            yield op;
           }
-          assem.append(op);
-        }
-        assem.endDocument();
-        userChangeset = Changeset.pack(cs.oldLen, cs.newLen, assem.toString(), cs.charBank);
+        })();
+        const serializedOps = Changeset.serializeOps(Changeset.squashOps(ops, true));
+        userChangeset = Changeset.pack(cs.oldLen, cs.newLen, serializedOps, cs.charBank);
         Changeset.checkRep(userChangeset);
 
         if (Changeset.isIdentity(userChangeset)) toSubmit = null;

src/tests/frontend/specs/easysync-other.js

@@ -112,16 +112,17 @@ describe('easysync-other', function () {
     describe('split/join attribution lines', function () {
       const testSplitJoinAttributionLines = (randomSeed) => {
         const stringToOps = (str) => {
-          const assem = Changeset.mergingOpAssembler();
-          const o = new Changeset.Op('+');
-          o.chars = 1;
-          for (let i = 0; i < str.length; i++) {
-            const c = str.charAt(i);
-            o.lines = (c === '\n' ? 1 : 0);
-            o.attribs = (c === 'a' || c === 'b' ? `*${c}` : '');
-            assem.append(o);
-          }
-          return assem.toString();
+          const ops = (function* () {
+            for (let i = 0; i < str.length; i++) {
+              const c = str.charAt(i);
+              const o = new Changeset.Op('+');
+              o.chars = 1;
+              o.lines = (c === '\n' ? 1 : 0);
+              o.attribs = (c === 'a' || c === 'b' ? `*${c}` : '');
+              yield o;
+            }
+          })();
+          return Changeset.serializeOps(Changeset.squashOps(ops, false));
         };
 
         it(`testSplitJoinAttributionLines#${randomSeed}`, async function () {