pr feedback

Author: PavelSafronov

src/bson.ts

@@ -55,13 +55,6 @@ export const readInt32LE = (buffer: Uint8Array, offset: number): number => {
   return NumberUtils.getInt32LE(buffer, offset);
 };
 
-// readUint32LE, reads a 32-bit unsigned integer from buffer at given offset
-// throws if offset is out of bounds
-export const readUint32LE = (buffer: Uint8Array, offset: number): number => {
-  validateBufferInputs(buffer, offset, 4);
-  return NumberUtils.getUint32LE(buffer, offset);
-};
-
 /**
  * BSON Serialization options.
  * @public

src/cmap/commands.ts

@@ -5,8 +5,7 @@ import {
   type Document,
   type Long,
   NumberUtils,
-  readInt32LE,
-  readUint32LE
+  readInt32LE
 } from '../bson';
 import { MongoInvalidArgumentError, MongoRuntimeError } from '../error';
 import { type ReadPreference } from '../read_preference';
@@ -576,6 +575,9 @@ export class OpMsgRequest {
     NumberUtils.setInt32LE(header, 4, this.requestId); // requestID
     NumberUtils.setInt32LE(header, 8, 0); // responseTo
     NumberUtils.setInt32LE(header, 12, OP_MSG); // opCode
+    // The OP_MSG spec calls out that flags is uint32:
+    // https://github.com/mongodb/specifications/blob/master/source/message/OP_MSG.md#op_msg-1
+    // Flags are limited to only 16 bits, so it does not matter that we are using setInt32LE method.
     NumberUtils.setInt32LE(header, 16, flags); // flags
     return buffers;
   }
@@ -716,7 +718,9 @@ export class OpMsgResponse {
     while (this.index < this.data.length) {
       const payloadType = this.data[this.index++];
       if (payloadType === 0) {
-        const bsonSize = readUint32LE(this.data, this.index);
+        // BSON spec specifies that this is a 32-bit signed integer: https://bsonspec.org/spec.html#:~:text=%3A%3A%3D-,int32,-e_list%20unsigned_byte(0
+        // Max BSON size is 16MB, which is well below 32-bit signed or unsigned limits, so we are choosing to read the value as Uint32
+        const bsonSize = readInt32LE(this.data, this.index);
         const bin = this.data.subarray(this.index, this.index + bsonSize);
 
         this.sections.push(bin);