STREAMS-1972: Add old shell compatibility for DBRef for JS Engine

Author: LijieZhang1998

snippets/mongocompat/mongotypes.js

@@ -602,36 +602,52 @@ if (typeof (DBPointer) != "undefined") {
 // DBRef
 if (typeof (DBRef) != "undefined") {
     DBRef.prototype.fetch = function() {
-        assert(this.$ref, "need a ns");
-        assert(this.$id, "need an id");
-        var coll = this.$db ? db.getSiblingDB(this.$db).getCollection(this.$ref) : db[this.$ref];
-        return coll.findOne({_id: this.$id});
+        assert(this.collection, "need a ns");
+        assert(this.oid, "need an id");
+        var coll = this.db ? db.getSiblingDB(this.db).getCollection(this.collection) : db[this.collection];
+        return coll.findOne({_id: this.oid});
     };
 
     DBRef.prototype.tojson = function(indent) {
         return this.toString();
     };
 
     DBRef.prototype.getDb = function() {
-        return this.$db || undefined;
+        return this.db || undefined;
     };
 
     DBRef.prototype.getCollection = function() {
-        return this.$ref;
+        return this.collection;
     };
 
     DBRef.prototype.getRef = function() {
-        return this.$ref;
+        return this.collection;
     };
 
     DBRef.prototype.getId = function() {
-        return this.$id;
+        return this.oid;
     };
 
     DBRef.prototype.toString = function() {
-        return "DBRef(" + tojson(this.$ref) + ", " + tojson(this.$id) +
-            (this.$db ? ", " + tojson(this.$db) : "") + ")";
+        return `DBRef("${this.collection}", ${this.oid.tojson()}` +
+            (this.db ? `, "${this.db}"` : "") + ")";
     };
+
+    Object.defineProperty(DBRef.prototype, "$ref", {
+        get: function () {
+            return this.collection;
+        },
+    });
+    Object.defineProperty(DBRef.prototype, "$id", {
+        get: function () {
+            return this.oid;
+        },
+    });
+    Object.defineProperty(DBRef.prototype, "$db", {
+        get: function () {
+            return this.db;
+        },
+    });
 } else {
     print("warning: no DBRef");
 }

snippets/mongocompat/test.js

@@ -70,3 +70,14 @@ assert.strictEqual(tsFromStr.i, 255);
 assert.strictEqual(tsFromStr.t, 0);
 assert.strictEqual(Timestamp.MAX_VALUE._bsontype, 'Long');
 assert.strictEqual(Timestamp.MAX_VALUE, Long.MAX_UNSIGNED_VALUE); 
+
+const id = ObjectId('68ffa28b77bba38c9ddcf376');
+const dbRef = DBRef('testColl', id, 'testDb');
+assert.strictEqual(dbRef.toString(), 'DBRef("testColl", ObjectId("68ffa28b77bba38c9ddcf376"), "testDb")');
+assert.strictEqual(dbRef.tojson(), 'DBRef("testColl", ObjectId("68ffa28b77bba38c9ddcf376"), "testDb")');
+assert.strictEqual(dbRef.$ref, 'testColl');
+assert.strictEqual(dbRef.$id, id);
+assert.strictEqual(dbRef.$db, 'testDb');
+const dbRefNoDb = DBRef('testColl', id);
+assert.strictEqual(dbRefNoDb.toString(), 'DBRef("testColl", ObjectId("68ffa28b77bba38c9ddcf376"))');
+assert.strictEqual(dbRefNoDb.$db, undefined);