idz: Port userdb/ onto common/

src/idz/userdb/decoder/index.ts

@@ -1,5 +1,4 @@
 import logger from "debug";
-import { Transform } from "stream";
 
 import { checkTeamName } from "./checkTeamName";
 import { createProfile } from "./createProfile";
@@ -49,6 +48,8 @@ import { updateTeamPoints } from "./updateTeamPoints";
 import { updateUiReport } from "./updateUiReport";
 import { updateUserLog } from "./updateUserLog";
 import { lockProfileExtend } from "./lockProfileExtend";
+import { BLOCK_SIZE } from "../../common";
+import { ByteStream } from "../../../util/stream";
 
 const debug = logger("app:idz:userdb:decoder");
 
@@ -119,88 +120,53 @@ for (const fn of funcList) {
   msgLengths.set(fn.msgCode, fn.msgLen);
 }
 
-function readHeader(buf: Buffer) {
-  return {
-    blah: "blah",
-  };
-}
+async function readRequest(stm: ByteStream): Promise<Request | undefined> {
+  const head = await stm.read(BLOCK_SIZE);
 
-export class Decoder extends Transform {
-  state: Buffer;
-
-  constructor() {
-    super({
-      readableObjectMode: true,
-      writableObjectMode: true,
-    });
-
-    this.state = Buffer.alloc(0);
+  if (head.length === 0) {
+    // Connection closed
+    return undefined;
   }
 
-  _transform(chunk: Buffer, encoding, callback) {
-    this.state = Buffer.concat([this.state, chunk]);
+  const msgCode = head.readUInt16LE(0x0000);
+  const msgLen = msgLengths.get(msgCode);
 
-    // Read header
+  if (msgLen === undefined) {
+    throw new Error(`Message ${msgCode.toString(16)}: Unknown command code`);
+  }
 
-    if (this.state.length < 0x04) {
-      return callback(null);
+  const tail = await stm.read(msgLen - BLOCK_SIZE);
+  const msg = Buffer.concat([head, tail]);
+
+  if (msg.length < msgLen) {
+    throw new Error(`Message ${msgCode.toString(16)}: Truncated read`);
+  }
+
+  if (debug.enabled) {
+    debug("Raw: %s", msg.toString("hex"));
+  }
+
+  const reader = readerFns.get(msgCode);
+
+  if (reader === undefined) {
+    throw new Error(`Message ${msgCode.toString(16)}: No read handler`);
+  }
+
+  const payload = reader(msg);
+
+  debug("Payload: %j", payload);
+
+  return payload;
+}
+
+export default async function* readRequestStream(stm: ByteStream) {
+  while (true) {
+    const req = await readRequest(stm);
+
+    if (req === undefined) {
+      return;
     }
 
-    const magic = this.state.readUInt32LE(0);
-
-    if (magic !== 0x01020304) {
-      return callback(
-        new Error(
-          "Invalid magic number, cryptographic processing probably incorrect."
-        )
-      );
-    }
-
-    if (this.state.length < 0x30) {
-      return callback(null);
-    }
-
-    const header = readHeader(this.state);
-
-    if (this.state.length < 0x32) {
-      return callback(null);
-    }
-
-    const msgCode = this.state.readUInt16LE(0x30);
-    const msgLen = msgLengths.get(msgCode);
-
-    if (msgLen === undefined) {
-      return callback(
-        new Error(
-          `Unknown command code ${msgCode.toString(16)}, cannot continue`
-        )
-      );
-    }
-
-    if (this.state.length < 0x30 + msgLen) {
-      return callback(null);
-    }
-
-    const reqBuf = this.state.slice(0, 0x30 + msgLen);
-    const payloadBuf = reqBuf.slice(0x30);
-
-    if (debug.enabled) {
-      debug("Raw: %s", reqBuf.toString("hex"));
-      debug("Header: %j", header);
-    }
-
-    const reader = readerFns.get(msgCode);
-
-    if (reader === undefined) {
-      return callback(
-        new Error(`No reader for command code ${msgCode.toString(16)}`)
-      );
-    }
-
-    const payload = reader(payloadBuf);
-
-    debug("Payload: %j", payload);
-
-    return callback(null, payload);
+    yield req;
   }
 }