avor parser offset fix; Readable interface update

sdk/storage/storage-internal-avro/src/AvroReadableFromStream.ts

@@ -1,11 +1,18 @@
-import { Readable } from "stream";
-import { AvroReadable } from './AvroReadable';
+import { AvroReadable } from "./AvroReadable";
 
 export class AvroReadableFromStream extends AvroReadable {
   private _position: number;
-  private _readable: Readable;
+  private _readable: NodeJS.ReadableStream;
+
+  private toUint8Array(data: string | Buffer): Uint8Array {
+    if (typeof data === "string") {
+      return Buffer.from(data);
+    }
+    return data;
+  }
+
   // private _stillReadable: boolean;
-  constructor(readable: Readable) {
+  constructor(readable: NodeJS.ReadableStream) {
     super();
     this._readable = readable;
     this._position = 0;
@@ -22,9 +29,14 @@ export class AvroReadableFromStream extends AvroReadable {
     return this._position;
   }
   public async read(size: number): Promise<Uint8Array> {
-    if (size <= 0) {
+    if (size < 0) {
       throw new Error(`size parameter should be positive: ${size}`);
     }
+
+    if (size === 0) {
+      return new Uint8Array();
+    }
+
     // readable is true if it is safe to call readable.read(), which means the stream has not been destroyed or emitted 'error' or 'end'.
     // if (!this._stillReadable || this._readable.destroyed) {
     if (!this._readable.readable) {
@@ -35,17 +47,16 @@ export class AvroReadableFromStream extends AvroReadable {
     if (chunk) {
       this._position += chunk.length;
       // chunk.lenght maybe less than desired size if the stream ends.
-      return chunk;
-    }
-    else {
+      return this.toUint8Array(chunk);
+    } else {
       // register callback to wait for enough data to read
       return new Promise((resolve, reject) => {
         const callback = () => {
           let chunk = this._readable.read(size);
           if (chunk) {
             this._position += chunk.length;
             // chunk.lenght maybe less than desired size if the stream ends.
-            resolve(chunk);
+            resolve(this.toUint8Array(chunk));
             this._readable.removeListener("readable", callback);
           }
         };