Improve performance for packstream in browser. (#809)

The buffer and utf-8 encoding implementation in browser was using the heap and `text-encoding-utf-8` library respectively. This process was really slower than in nodejs. For example, a string with 85000 length was taking 180 seconds to serialize in the browser, the same string takes milliseconds to be serialised in nodejs.

This performance issue was resolved by using the libraries `buffer` and `string_decoder`, libraries which is already available in nodejs, also in browser. This substitution bring the serialisation of the 85000 length string to take only 350 ms when it's done in browser.

The `text-encoding-utf-8` was removed from the project dependency in the process.

Author: bigmontz

packages/bolt-connection/package-lock.json

@@ -38,7 +38,8 @@
     "typescript": "^4.4.4"
   },
   "dependencies": {
+    "buffer": "^6.0.3",
     "neo4j-driver-core": "^4.4.0-dev",
-    "text-encoding-utf-8": "^1.0.2"
+    "string_decoder": "^1.3.0"
   }
 }

packages/bolt-connection/package.json

@@ -17,7 +17,7 @@
  * limitations under the License.
  */
 
-import HeapBuffer from './browser-buf'
+import ChannelBuffer from '../channel-buf'
 import { newError, internal } from 'neo4j-driver-core'
 
 const {
@@ -83,7 +83,7 @@ export default class WebSocketChannel {
     }
     this._ws.onmessage = event => {
       if (self.onmessage) {
-        const b = new HeapBuffer(event.data)
+        const b = new ChannelBuffer(event.data)
         self.onmessage(b)
       }
     }
@@ -130,14 +130,14 @@ export default class WebSocketChannel {
 
   /**
    * Write the passed in buffer to connection
-   * @param {HeapBuffer} buffer - Buffer to write
+   * @param {ChannelBuffer} buffer - Buffer to write
    */
   write (buffer) {
     // If there is a pending queue, push this on that queue. This means
     // we are not yet connected, so we queue things locally.
     if (this._pending !== null) {
       this._pending.push(buffer)
-    } else if (buffer instanceof HeapBuffer) {
+    } else if (buffer instanceof ChannelBuffer) {
       try {
         this._ws.send(buffer._buffer)
       } catch (error) {

packages/bolt-connection/src/channel/browser/browser-buf.js

@@ -17,10 +17,8 @@
  * limitations under the License.
  */
 
-import HeapBuffer from './browser-buf'
 import WebSocketChannel from './browser-channel'
 import BrowserHosNameResolver from './browser-host-name-resolver'
-import utf8Codec from './browser-utf8'
 
 /*
 
@@ -32,8 +30,5 @@ Such imports are replaced at build time with `browser/index.js` when building a
 NOTE: exports in this module should have exactly the same names/structure as exports in `node/index.js`.
 
  */
-
-export const alloc = arg => new HeapBuffer(arg)
 export const Channel = WebSocketChannel
 export const HostNameResolver = BrowserHosNameResolver
-export const utf8 = utf8Codec

packages/bolt-connection/src/channel/browser/browser-channel.js

@@ -17,12 +17,12 @@
  * limitations under the License.
  */
 
-import node from 'buffer'
-import BaseBuffer from '../../buf'
+import buffer from 'buffer'
+import BaseBuffer from '../buf'
 
-export default class NodeBuffer extends BaseBuffer {
+export default class ChannelBuffer extends BaseBuffer {
   constructor (arg) {
-    const buffer = newNodeJSBuffer(arg)
+    const buffer = newChannelJSBuffer(arg)
     super(buffer.length)
     this._buffer = buffer
   }
@@ -52,7 +52,7 @@ export default class NodeBuffer extends BaseBuffer {
   }
 
   putBytes (position, val) {
-    if (val instanceof NodeBuffer) {
+    if (val instanceof ChannelBuffer) {
       const bytesToCopy = Math.min(
         val.length - val.position,
         this.length - position
@@ -70,22 +70,33 @@ export default class NodeBuffer extends BaseBuffer {
   }
 
   getSlice (start, length) {
-    return new NodeBuffer(this._buffer.slice(start, start + length))
+    return new ChannelBuffer(this._buffer.slice(start, start + length))
   }
 }
 
-function newNodeJSBuffer (arg) {
-  if (arg instanceof node.Buffer) {
+/**
+ * Allocate a buffer
+ * 
+ * @param {number} size The buffer sizzer
+ * @returns {BaseBuffer} The buffer
+ */
+export function alloc (size) {
+  return new ChannelBuffer(size)
+}
+
+
+function newChannelJSBuffer (arg) {
+  if (arg instanceof buffer.Buffer) {
     return arg
   } else if (
     typeof arg === 'number' &&
-    typeof node.Buffer.alloc === 'function'
+    typeof buffer.Buffer.alloc === 'function'
   ) {
     // use static factory function present in newer NodeJS versions to allocate new buffer with specified size
-    return node.Buffer.alloc(arg)
+    return buffer.Buffer.alloc(arg)
   } else {
     // fallback to the old, potentially deprecated constructor
     // eslint-disable-next-line node/no-deprecated-api
-    return new node.Buffer(arg)
+    return new buffer.Buffer(arg)
   }
 }

packages/bolt-connection/src/channel/browser/browser-utf8.js

@@ -18,7 +18,7 @@
  */
 
 import BaseBuffer from '../buf/base-buf'
-import { alloc } from './node'
+import { alloc } from './channel-buf'
 import CombinedBuffer from './combined-buf'
 
 const _CHUNK_HEADER_SIZE = 2

packages/bolt-connection/src/channel/browser/index.js

@@ -18,7 +18,7 @@
  */
 
 import { BaseBuffer } from '../buf'
-import { alloc } from './node'
+import { alloc } from './channel-buf'
 
 /**
  * Buffer that combines multiple buffers, exposing them as one single buffer.

packages/bolt-connection/src/channel/node/node-buf.js renamed to packages/bolt-connection/src/channel/channel-buf.js

@@ -1,5 +1,3 @@
-import ChannelConfig from './channel-config'
-
 /**
  * Copyright (c) "Neo4j"
  * Neo4j Sweden AB [http://neo4j.com]
@@ -18,6 +16,9 @@ import ChannelConfig from './channel-config'
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 export * from './node'
 export * from './chunking'
 export { default as ChannelConfig } from './channel-config'
+export { alloc } from './channel-buf'
+export { default as utf8 } from './utf8'