From 4f8c9369744bfa4b1223cec916cb0e5b261831dc Mon Sep 17 00:00:00 2001
From: Yoshiya Hinosawa <stibium121@gmail.com>
Date: Thu, 31 Oct 2019 23:57:09 +0900
Subject: [PATCH] Make EOF unique symbol (#3244)

---
 cli/js/io.ts                 |  7 ++-----
 cli/js/lib.deno_runtime.d.ts | 12 +++++-------
 cli/js/tls_test.ts           |  9 ++++++++-
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/cli/js/io.ts b/cli/js/io.ts
index 1a7bf8c4c2..15a4ad09ba 100644
--- a/cli/js/io.ts
+++ b/cli/js/io.ts
@@ -3,11 +3,8 @@
 // Documentation liberally lifted from them too.
 // Thank you! We love Go!
 
-// TODO(kt3k): EOF should be `unique symbol` type.
-// That might require some changes of ts_library_builder.
-// See #2591 for more details.
-export const EOF = null;
-export type EOF = null;
+export const EOF: unique symbol = Symbol("EOF");
+export type EOF = typeof EOF;
 
 // Seek whence values.
 // https://golang.org/pkg/io/#pkg-constants
diff --git a/cli/js/lib.deno_runtime.d.ts b/cli/js/lib.deno_runtime.d.ts
index c0bebf4616..4331319bf5 100644
--- a/cli/js/lib.deno_runtime.d.ts
+++ b/cli/js/lib.deno_runtime.d.ts
@@ -83,8 +83,8 @@ declare namespace Deno {
 
   // @url js/io.d.ts
 
-  export const EOF: null;
-  export type EOF = null;
+  export const EOF: unique symbol;
+  export type EOF = typeof EOF;
   export enum SeekMode {
     SEEK_START = 0,
     SEEK_CURRENT = 1,
@@ -2283,8 +2283,6 @@ declare namespace eventTarget {
 declare namespace io {
   // @url js/io.d.ts
 
-  export const EOF: null;
-  export type EOF = null;
   export enum SeekMode {
     SEEK_START = 0,
     SEEK_CURRENT = 1,
@@ -2308,10 +2306,10 @@ declare namespace io {
      *
      * Implementations must not retain `p`.
      */
-    read(p: Uint8Array): Promise<number | EOF>;
+    read(p: Uint8Array): Promise<number | Deno.EOF>;
   }
   export interface SyncReader {
-    readSync(p: Uint8Array): number | EOF;
+    readSync(p: Uint8Array): number | Deno.EOF;
   }
   export interface Writer {
     /** Writes `p.byteLength` bytes from `p` to the underlying data
@@ -2387,7 +2385,7 @@ declare namespace fetchTypes {
     formData(): Promise<domTypes.FormData>;
     json(): Promise<any>;
     text(): Promise<string>;
-    read(p: Uint8Array): Promise<number | io.EOF>;
+    read(p: Uint8Array): Promise<number | Deno.EOF>;
     close(): void;
     cancel(): Promise<void>;
     getReader(): domTypes.ReadableStreamReader;
diff --git a/cli/js/tls_test.ts b/cli/js/tls_test.ts
index 58cafd23e7..6966a69112 100644
--- a/cli/js/tls_test.ts
+++ b/cli/js/tls_test.ts
@@ -184,7 +184,10 @@ testPerm({ read: true, net: true }, async function dialAndListenTLS(): Promise<
   await w.flush();
   const tpr = new TextProtoReader(r);
   const statusLine = await tpr.readLine();
-  assert(!!statusLine, "line must be read: " + statusLine);
+  assert(statusLine !== Deno.EOF, `line must be read: ${String(statusLine)}`);
+  if (statusLine === Deno.EOF) {
+    return;
+  }
   const m = statusLine.match(/^(.+?) (.+?) (.+?)$/);
   assert(m !== null, "must be matched");
   const [_, proto, status, ok] = m;
@@ -192,6 +195,10 @@ testPerm({ read: true, net: true }, async function dialAndListenTLS(): Promise<
   assertEquals(status, "200");
   assertEquals(ok, "OK");
   const headers = await tpr.readMIMEHeader();
+  assert(headers !== Deno.EOF);
+  if (headers === Deno.EOF) {
+    return;
+  }
   const contentLength = parseInt(headers.get("content-length"));
   const bodyBuf = new Uint8Array(contentLength);
   await r.readFull(bodyBuf);