Add TooLarge error code for buffers (#1298)

In collaboration with @yushimatenjin

3 files changed, 26 insertions, 2 deletions

diff --git a/js/buffer.ts b/js/buffer.ts
index 4e9cd6eb2..9e06eecd4 100644
--- a/js/buffer.ts
+++ b/js/buffer.ts
@@ -6,6 +6,7 @@
 import { Reader, Writer, ReadResult } from "./io";
 import { assert } from "./util";
 import { TextDecoder } from "./text_encoding";
+import { DenoError, ErrorKind } from "./errors";
 
 // MIN_READ is the minimum ArrayBuffer size passed to a read call by
 // buffer.ReadFrom. As long as the Buffer has at least MIN_READ bytes beyond
@@ -170,7 +171,10 @@ export class Buffer implements Reader, Writer {
       // don't spend all our time copying.
       copyBytes(this.buf, this.buf.subarray(this.off));
     } else if (c > MAX_SIZE - c - n) {
-      throw Error("ErrTooLarge"); // TODO DenoError(TooLarge)
+      throw new DenoError(
+        ErrorKind.TooLarge,
+        "The buffer cannot be grown beyond the maximum size."
+      );
     } else {
       // Not enough space anywhere, we need to allocate.
       const buf = new Uint8Array(2 * c + n);
diff --git a/js/buffer_test.ts b/js/buffer_test.ts
index 58668de26..2683b3862 100644
--- a/js/buffer_test.ts
+++ b/js/buffer_test.ts
@@ -1,9 +1,9 @@
 import { Buffer, readAll } from "deno";
+import * as deno from "deno";
 // This code has been ported almost directly from Go's src/bytes/buffer_test.go
 // Copyright 2009 The Go Authors. All rights reserved. BSD license.
 // https://github.com/golang/go/blob/master/LICENSE
 import { assert, assertEqual, test } from "./test_util.ts";
-
 // N controls how many iterations of certain checks are performed.
 const N = 100;
 let testBytes: Uint8Array | null;
@@ -130,6 +130,25 @@ test(async function bufferLargeByteWrites() {
   check(buf, "");
 });
 
+test(async function bufferTooLargeByteWrites() {
+  init();
+  const tmp = new Uint8Array(72);
+  const growLen = Number.MAX_VALUE;
+  const xBytes = repeat("x", 0);
+  const buf = new Buffer(xBytes.buffer as ArrayBuffer);
+  const { nread, eof } = await buf.read(tmp);
+
+  let err;
+  try {
+    buf.grow(growLen);
+  } catch (e) {
+    err = e;
+  }
+
+  assertEqual(err.kind, deno.ErrorKind.TooLarge);
+  assertEqual(err.name, "TooLarge");
+});
+
 test(async function bufferLargeByteReads() {
   init();
   const buf = new Buffer();
diff --git a/src/msg.fbs b/src/msg.fbs
index d6bbc220e..ecfb9e50c 100644
--- a/src/msg.fbs
+++ b/src/msg.fbs
@@ -105,6 +105,7 @@ enum ErrorKind: byte {
   HttpCanceled,
   HttpParse,
   HttpOther,
+  TooLarge,
 }
 
 table Cwd {}