crypto: address review feedback for randomUUIDv7

- Make version/variant required params in serializeUUID
- Share buffer pools (uuidData/uuidNotBuffered) between v4 and v7

Author: nabeel378

lib/internal/crypto/random.js

@@ -360,7 +360,7 @@ function getHexBytes() {
   return hexBytesCache;
 }
 
-function serializeUUID(buf, offset = 0, version = 0x40, variant = 0x80) {
+function serializeUUID(buf, version, variant, offset = 0) {
   const kHexBytes = getHexBytes();
   // xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
   return kHexBytes[buf[offset]] +
@@ -392,15 +392,15 @@ function getBufferedUUID() {
 
   if (uuidBatch === 0) randomFillSync(uuidData);
   uuidBatch = (uuidBatch + 1) % kBatchSize;
-  return serializeUUID(uuidData, uuidBatch * 16);
+  return serializeUUID(uuidData, 0x40, 0x80, uuidBatch * 16);
 }
 
 function getUnbufferedUUID() {
   uuidNotBuffered ??= secureBuffer(16);
   if (uuidNotBuffered === undefined)
     throw new ERR_OPERATION_FAILED('Out of memory');
   randomFillSync(uuidNotBuffered);
-  return serializeUUID(uuidNotBuffered);
+  return serializeUUID(uuidNotBuffered, 0x40, 0x80);
 }
 
 function randomUUID(options) {
@@ -415,10 +415,6 @@ function randomUUID(options) {
   return disableEntropyCache ? getUnbufferedUUID() : getBufferedUUID();
 }
 
-let uuidV7Data;
-let uuidV7NotBuffered;
-let uuidV7Batch = 0;
-
 function writeTimestamp(buf, offset) {
   const now = DateNow();
   const msb = now / (2 ** 32);
@@ -431,24 +427,24 @@ function writeTimestamp(buf, offset) {
 }
 
 function getBufferedUUIDv7() {
-  uuidV7Data ??= secureBuffer(16 * kBatchSize);
-  if (uuidV7Data === undefined)
+  uuidData ??= secureBuffer(16 * kBatchSize);
+  if (uuidData === undefined)
     throw new ERR_OPERATION_FAILED('Out of memory');
 
-  if (uuidV7Batch === 0) randomFillSync(uuidV7Data);
-  uuidV7Batch = (uuidV7Batch + 1) % kBatchSize;
-  const offset = uuidV7Batch * 16;
-  writeTimestamp(uuidV7Data, offset);
-  return serializeUUID(uuidV7Data, offset, 0x70);
+  if (uuidBatch === 0) randomFillSync(uuidData);
+  uuidBatch = (uuidBatch + 1) % kBatchSize;
+  const offset = uuidBatch * 16;
+  writeTimestamp(uuidData, offset);
+  return serializeUUID(uuidData, 0x70, 0x80, offset);
 }
 
 function getUnbufferedUUIDv7() {
-  uuidV7NotBuffered ??= secureBuffer(16);
-  if (uuidV7NotBuffered === undefined)
+  uuidNotBuffered ??= secureBuffer(16);
+  if (uuidNotBuffered === undefined)
     throw new ERR_OPERATION_FAILED('Out of memory');
-  randomFillSync(uuidV7NotBuffered, 6);
-  writeTimestamp(uuidV7NotBuffered, 0);
-  return serializeUUID(uuidV7NotBuffered, 0, 0x70);
+  randomFillSync(uuidNotBuffered, 6);
+  writeTimestamp(uuidNotBuffered, 0);
+  return serializeUUID(uuidNotBuffered, 0x70, 0x80);
 }
 
 function randomUUIDv7(options) {