From a829fa8f57a2063492aab564ec1f15da21eb851c Mon Sep 17 00:00:00 2001
From: Marcos Casagrande <marcoscvp90@gmail.com>
Date: Sat, 27 Jun 2020 22:55:01 +0200
Subject: feat(std/io): add fromStreamReader, fromStreamWriter (#5789)

---
 std/io/streams.ts | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 std/io/streams.ts

(limited to 'std/io/streams.ts')

diff --git a/std/io/streams.ts b/std/io/streams.ts
new file mode 100644
index 000000000..3969746ef
--- /dev/null
+++ b/std/io/streams.ts
@@ -0,0 +1,34 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+export function fromStreamWriter(
+  streamWriter: WritableStreamDefaultWriter<Uint8Array>
+): Deno.Writer {
+  return {
+    async write(p: Uint8Array): Promise<number> {
+      await streamWriter.ready;
+      await streamWriter.write(p);
+      return p.length;
+    },
+  };
+}
+
+export function fromStreamReader(
+  streamReader: ReadableStreamDefaultReader<Uint8Array>
+): Deno.Reader {
+  const buffer = new Deno.Buffer();
+
+  return {
+    async read(p: Uint8Array): Promise<number | null> {
+      if (buffer.empty()) {
+        const res = await streamReader.read();
+        if (res.done) {
+          return null; // EOF
+        }
+
+        await Deno.writeAll(buffer, res.value);
+      }
+
+      return buffer.read(p);
+    },
+  };
+}
-- 
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