feat: send w/ fast header

Author: ronag

src/message/message-builder.js

@@ -1,25 +1,104 @@
 import * as C from '../constants/constants.js'
+import * as utils from '../utils/utils.js'
+import varint from 'varint'
 
-const SEP = C.MESSAGE_PART_SEPERATOR
+const poolEncoder = new globalThis.TextEncoder()
+
+// TODO (fix): Don't assume maxMesageSize is 1MB
+const maxMessageSize = 1024 * 1024
+const poolSize = maxMessageSize * 8
+
+let poolBuffer
+let poolView
+let poolOffset
+
+function reallocPool() {
+  poolBuffer = utils.isNode
+    ? globalThis.Buffer.allocUnsafe(poolSize)
+    : new Uint8Array(new ArrayBuffer(poolSize))
+  poolView = new DataView(poolBuffer.buffer)
+  poolOffset = 0
+}
+
+function alignPool() {
+  // Ensure aligned slices
+  if (poolOffset & 0x7) {
+    poolOffset |= 0x7
+    poolOffset++
+  }
+}
+
+function writeString(dst, str, offset) {
+  if (utils.isNode) {
+    return dst.write(str, offset)
+  } else {
+    const res = poolEncoder.encodeInto(str, new Uint8Array(dst.buffer, offset))
+    return res.written
+  }
+}
 
 export function getMsg(topic, action, data) {
   if (data && !(data instanceof Array)) {
     throw new Error('data must be an array')
   }
 
-  const sendData = [topic, action]
+  if (!poolBuffer || poolOffset + maxMessageSize > poolSize) {
+    reallocPool()
+  } else {
+    alignPool()
+  }
+
+  const start = poolOffset
+
+  const headerSize = 8
+  for (let n = 0; n < headerSize; n++) {
+    poolBuffer[poolOffset++] = 0
+  }
+
+  let headerPos = start
+  poolBuffer[headerPos++] = 128 + headerSize
+
+  poolBuffer[poolOffset++] = topic.charCodeAt(0)
+  poolBuffer[poolOffset++] = 31
+  for (let n = 0; n < action.length; n++) {
+    poolBuffer[poolOffset++] = action.charCodeAt(n)
+  }
 
   if (data) {
     for (let i = 0; i < data.length; i++) {
-      if (typeof data[i] === 'object') {
-        sendData.push(JSON.stringify(data[i]))
+      const type = typeof data[i]
+      let len
+      if (data[i] == null) {
+        poolBuffer[poolOffset++] = 31
+        len = 0
+      } else if (type === 'object') {
+        poolBuffer[poolOffset++] = 31
+        len = writeString(poolBuffer, JSON.stringify(data[i]), poolOffset)
+      } else if (type === 'bigint') {
+        poolBuffer[poolOffset++] = 31
+        poolView.setBigUint64(poolOffset, data[i], false)
+        len = 8
+      } else if (type === 'string') {
+        poolBuffer[poolOffset++] = 31
+        len = writeString(poolBuffer, data[i], poolOffset)
       } else {
-        sendData.push(data[i])
+        throw new Error('invalid data')
+      }
+      poolOffset += len
+
+      varint.encode(len + 1, poolBuffer, headerPos)
+      headerPos += varint.encode.bytes
+      if (headerPos - start >= headerSize) {
+        throw new Error('header too large')
+      }
+
+      if (poolOffset >= poolSize) {
+        throw new Error('message too large')
       }
     }
   }
 
-  return sendData.join(SEP)
+  return new Uint8Array(poolBuffer.buffer, start, poolOffset - start)
 }
 
 export function typed(value) {